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1
Ahmed, Ibrahim Saad M. "Voltage breakdown in polluted insulators." Thesis, University of Exeter, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236513.
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Coaker, Brian M. "Mechanisms for triggering high-voltage breakdown in vacuum." Thesis, Aston University, 1995. http://publications.aston.ac.uk/8236/.
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The electrical and optical characteristics of a cylindrical alumina insulator (94% Al203) have been measured under ultra-high vacuum (P < 10-8 mBar) conditions. A high-resolution CCD camera was used to make real-time optical recordings of DC prebreakdown luminescence from the ceramic, under conditions where DC current magnitudes were limited to less than 50μA. Two concentric metallized rings formed a pair of co-axial electrodes, on the end-face of the alumina tube; a third 'transparent' electrode was employed to study the effect of an orthogonal electric field upon the radial conduction processes within the metallized alumina specimen. The wavelength-spectra of the emitted light was quantified using a high-speed scanning monochromator and photo-multiplier tube detector. Concurrent electrical measurements were made alongside the recording of optical-emission images. An observed time-dependence of the photon-emission is correlated with a time-variation observed in the DC current-voltage characteristics of the alumina. Optical images were also recorded of pulsed-field surface-flashover events on the alumina ceramic. An intensified high-speed video technique provided 1ms frames of surface-flashover events, whilst 100ns frames were achieved using an ultra high-speed fast-framing camera. By coupling this fast-frame camera to a digital storage oscilloscope, it was possible to establish a temporal correlation between the application of a voltage-pulse to the ceramic and the evolution of photonic emissions from the subsequent surface-flashover event. The electro-optical DC prebreakdown characteristics of the alumina are discussed in terms of solid-state photon-emission processes, that are believed to arise from radiative electron-recombination at vacancy-defects and substitutional impurity centres within the surface-layers of the ceramic. The physical nature of vacancy-defects within an alumina dielectric is extensively explored, with a particular focus placed upon the trapped electron energy-levels that may be present at these defect centres. Finally, consideration is given to the practical application of alumina in the trigger-ceramic of a sealed triggered vacuum gap (TVG) switch. For this purpose, a physical model describing the initiation of electrical breakdown within the TVG regime is proposed, and is based upon the explosive destabilisation of trapped charge within the alumina ceramic, triggering the onset of surface-flashover along the insulator. In the main-gap prebreakdown phase, it is suggested that the electrical-breakdown of the TVG is initiated by the low-field 'stripping' of prebreakdown electrons from vacancy-defects in the ceramic under the influence of an orthogonal main-gap electric field.
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Milošević, Borka. "On voltage stability monitoring and control using multiagent systems." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/16355.
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Boudjelthia, H. "Corona suppression on high voltage direct current systems." Thesis, University of Southampton, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235291.
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Hasan, Samil Mukhlisin Yauma 1967. "Neutron irradiation effects on the breakdown voltage of power MOSFETs." Thesis, The University of Arizona, 1993. http://hdl.handle.net/10150/278361.
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The effect of neutron irradiation on power metal-oxide-semiconductor field effect transistors (power MOSFETs) breakdown voltage has been investigated. Power MOSFETs of both n- and p-channel with manufacturer's rated breakdown voltage between 100 to 500V were radiated up to accumulated neutron fluence of 5x10¹⁴ neutron/cm² Considerable increase in the breakdown voltages were observed in n-type MOSFETs after 10¹³ neutron/cm² and to p-type MOSFETs after 10¹² neutron/cm² The increase in breakdown voltages is due to the decrease in the mean free path caused by the neutron-irradiation-induced defects. The effect of positive trapped charge oxide and the termination structure to the breakdown voltage were considered. S-PISCES 2B device simulation was used to investigate the change in the b coefficient of Chynoweth's law that relates to the mean free path. Two empirical models are presented: one predicts the power MOSFET breakdown voltage after a certain amount of neutron fluence and the other considers the change in the b coefficient after some amount of neutron radiation to predict the change of breakdown voltage in a device simulation.
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Okubo, Hitoshi, Tetsu Shioiri, Mitsutaka Homma, Hiroki Kojima, Ryouki Nishimura, and Keita Aoki. "Enhancement of Breakdown Strength by Microdischarge under Impulse Voltage Applications in Vacuum." IEEE, 2010. http://hdl.handle.net/2237/14534.
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Suchanek, Richard Donald III. "Breakdown Voltage Performances of Aluminum and Copper Conductor Wire Under Compression Stresses." TopSCHOLAR®, 2016. http://digitalcommons.wku.edu/theses/1606.
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In the global, competitive market of energy transformation, increased operational expenses and depletion of raw materials have resulted in companies pursuing alternate materials to reduce consumer costs. In electrical applications, energy is transformed using materials with high electrical conductive properties. The conductive material used to transmit a signal is called conductor wire and is comprised of any material that has the ability to move charged particles from one point to another without propagation or delay. The conductor wire in many applications is encapsulated in epoxy resin called enamel. The enamel is the insulation system that provides necessary dielectric clearances to prevent voltage leakage. The most common form of energy transformation is the electric motor. Both copper and aluminum conductor wire are commonly used in electric motors, but copper is preferred due to thermal and electrical properties. However, there is a significant economic incentive to convert to aluminum conductor wire. Limited white papers are available comparing the performances of the two materials; the research is limited to physical and electrical performances of the raw material and does not take into considering the insulation. The conductor wire, which includes the insulation, is susceptible to damage during the manufacturing process and is an inherent risk if not fully understood. During the blocking process, the conductor wire is pushed and compressed into lamination slots. This process changes the conductor wire outer diameter to accommodate void spaces within the lamination slots. The percentage of slot area occupied by the conductor wire is known as slot fill. The higher the slot fill, the more wire occupying the available space. The higher the slot fill, the more force required to fill the slots. High slot fill motor designs provide a performance advantage with little associated cost. The more wire pressed into the slot, the higher the potential efficiency gains. However, high slot fill motors are more susceptible to damage.
The study is designed to evaluate and measure the durability of aluminum and copper conductor wire under simulated compression stresses. Utilizing this information, electric motor manufacturers can push current design limits without affecting conductor wire quality and reliability.
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Meng, Wentao. "Simulation Studies of High Breakdown-Voltage GaN and β-Ga2O3 Vertical Device." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu155558352423293.
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Ghosh, Gargi. "Dependence of Set, Reset and Breakdown Voltages of a MIM Resistive Memory Device on the Input Voltage Waveform." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/52704.
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Owing to its excellent scaling potential, low power consumption, high switching speed, and good retention, and endurance properties, Resistive Random Access Memory (RRAM) is one of the prime candidates to supplant current Nonvolatile Memory (NVM) based on the floating gate (FG) MOSFET transistor, which is at the end of its scaling capability. The RRAM technology comprises two subcategories: 1) the resistive phase change memory (PCM), which has been very recently deployed commercially, and 2) the filamentary conductive bridge RAM (CBRAM) which holds the promise of even better scaling potential, less power consumption, and faster access times. This thesis focuses on several aspects of the CBRAM technology. CBRAM devices are based on nanoionics transport and chemo-physical reactions to create filamentary conductive paths across a dielectric sandwiched between two metal electrodes. These nano-size filaments can be formed and ruptured reliably and repeatedly by application of appropriate voltages. Although, there exists a large body of literature on this topic, many aspects of the CBRAM mechanisms and are still poorly understood. In the next paragraph, the aspects of CBRAM studied in this thesis are spelled out in more detail.
CBRAM cell is not only an attractive candidate for a memory cell but is also a good implementation of a new circuit element, called memristor, as postulated by Leon Chua. Basically, a memristor, is a resistor with a memory. Such an element holds the promise to mimic neurological switching of neuron and synapses in human brain that are much more efficient than the Neuman computer architecture with its current CMOS logic technology. A memristive circuitry can possibly lead to much more powerful neural computers in the future. In the course of the research undertaken in this thesis, many memristive properties of the resistive cells have been found and used in models to describe the behavior of the resistive switching devices.
The research performed in this study has also an immediate commercial application. Currently, the semiconductor industry is faced with so-called latency scaling dilemma. In the past, the bottleneck for the signal propagation was the time delay of the transistor. Today, the transistors became so fast that the bottleneck for the signal propagation is now the RC time delay of the interconnecting metal lines. Scaling drives both, resistance and parasitic capacitance of the metal lines to very high values.
In this context, one observes that resistive switching memory does not require a Si substrate. It is therefore an excellent candidate for its implementation as an o n-chip memory above the logic circuits in the CMOS back-end, thus making the signal paths between logic and memory extremely short. In the framework of a Semiconductor Research Corporation (SRC) project with Intel Corporation, this thesis investigated the breakdown and resistive switching properties of currently deployed low k interlayer dielectrics to understand the mechanisms and potential of different material choices for a realization of an RRAM memory to be implemented in the back-end of a CMOS process flow.Master of Science
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Lipham, Mark Lawrence Kirkici Hulya. "Electrical breakdown studies of partial pressure argon under Khz range pulse voltages." Auburn, Ala., 2010. http://hdl.handle.net/10415/2044.
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Niwa, Hiroki. "Breakdown Characteristics in SiC and Improvement of PiN Diodes toward Ultrahigh-Voltage Applications." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/215548.
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Kutty, Karan. "CLASS-E CASCODE POWER AMPLIFIER ANALYSIS AND DESIGN FOR LONG TERM RELIABILITY." Master's thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2703.
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This study investigated the Class-E power amplifier operating at 5.2 GHz. Since the operation of this amplifier applies a lot of stress on the switching transistor, a cascode topology was applied in order to reduce the drain-source voltage stress. Such an amplifier was designed and optimized in order to improve stability, power added efficiency, and matching. A layout for the said design was then created to be fabrication-ready using the TSMC 0.18 um technology. Post-layout simulations were performed in order to realize a more realistic circuit performance with the layout design in mind. Long-term stress effects, such as oxide breakdown, on the key transistors were modeled and simulated in order to achieve an understanding of how leakage currents affect the overall circuit performance. Simulated results were compared and contrasted against theoretical understanding using derived equations. Recommendations for future advancements were made for modification and optimization of the circuit by the application of other stress reduction strategies, variation in the class-E topology, and improvement of the driver stage.M.S.E.E.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering MSEE
13
Bobkov, Volodymyr. "Studies of high voltage breakdown phenomena on ICRF (ion cyclotron range of frequencies) antennas." [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968917844.
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Fujishima, Naoto. "A novel trench lateral power MOSFET with high breakdown voltage and low on-resistance." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0025/MQ34132.pdf.
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Kosier, Steven Louie 1966. "The effects of ionizing radiation on the breakdown voltage of p-channel power MOSFETs." Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/277798.
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The effects of ionizing radiation on the breakdown voltage of p-channel power MOSFETs were examined through two-dimensional simulation. The response of a reverse-biased n+-p junction to positive oxide-trapped charge, Not, is examined in detail, and analytical expressions for its characteristics are derived. These results provide insight into the breakdown performance of p-channel power MOSFETs in ionizing radiation environments, whose performance was found to be very different from corresponding n-channel power MOSFETs. Insights gained through analysis of p-channel devices suggest a termination/isolation scheme, the VLD-FRR, that will enhance p-channel device reliability in radiation environments. Two introductory chapters, which also serve as literature reviews, are provided. The buildup of Not in thick oxides and breakdown voltage of the power DMOS transistor are both reviewed, with attention focused on p-channel devices in both cases. Finally, suggestions for future work are given.
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Li, Xiaoyong. "Added CFO voltages from fiberglass poles and its electrical degradation." Master's thesis, Mississippi State : Mississippi State University, 2001. http://library.msstate.edu/etd/show.asp?etd=etd-11092001-113706.
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Hayakawa, Naoki, 直樹 早川, Hitoshi Okubo, and 仁. 大久保. "Feature article - Lifetime Characteristics of Nanocomposite Enameled Wire Under Surge Voltage Application." IEEE, 2008. http://hdl.handle.net/2237/11172.
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Vogelsang, Ruben. "Time to breakdown of high voltage winding insulations with respect to microscopic properties and manufacturing qualities /." [S.l.] : [s.n.], 2004. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=15656.
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Wang, Yong. "Research on improvement of breakdown voltage of AlGaN/GaN HEMTs grown on Si(111) substrates by MOCVD /." View abstract or full-text, 2009. http://library.ust.hk/cgi/db/thesis.pl?ECED%202009%20WANGY.
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Hayakawa, Naoki, Hiroshi Inano, Yusuke Nakamura, and Hitoshi Okubo. "Time Variation of Partial Discharge Activity Leading to Breakdown of Magnet Wire under Repetitive Surge Voltage Application." IEEE, 2008. http://hdl.handle.net/2237/12126.
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Mossor, Charles W. "Electrical Breakdown of Thermal Spray Alumina Ceramic Applied to AlSiC Baseplates Used in Power Module Packaging." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/33543.
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Thermal spray coatings offer new alternatives in the production of electronic power modules that use alumina ceramic as an isolation layer. Current processes use direct bond copper (DBC) soldered to a nickel plated copper heat spreader. A coefficient of thermal expansion (CTE) mismatch exists between copper and alumina and leads to reliability issues that arise due to product failure during thermal cycling and lifetime operation. The substitution of an AlSiC metal matrix composite (MMC) heat spreader baseplate addresses the problem of CTE mismatch and will reduce the number of product failures related to cracking and delamination caused by this pronounced mismatch in the thermal expansion coefficient..
The substitution of an AlSiC (MMC) heat spreader baseplate also allows the production process to be achieved with a fewer number of metallization layers. Thermal spray can apply alumina ceramic coatings directly to the AlSiC (MMC) baseplates. A reduction in process steps will lead to a reduction in manufacturing costs, the main driving objective in Microelectronics Industries.
Thermal spray coatings have a major problem since they have a porous microstructure which can trap undesired moisture. The moisture basically causes the coatings to have a lower dielectric breakdown voltage and a higher leakage current at normal operating voltages. This problem can be eliminated by manufacturing the electronic power modules in a controlled environment and packaging the devices in a hermetically sealed package.
This thesis analyzes the data obtained from direct-voltage dielectric breakdown and direct-voltage leakage current tests conducted on coupons manufactured using the thermal plasma spray coating process and the thermal high-velocity oxyfuel (HVOF) coating process. ASTM specifications defining appropriate testing procedures are used in testing the dielectric strength of these coupons.
Issues relating to the dielectric strength and dielectric leakage current are evaluated and validated at the Microelectronics Laboratory at Virginia Polytechnic Institute & State University. The objective to conduct this research study using plasma and HVOF alumina coatings as dielectric isolation layers is to support the Microelectronics Industries in developing a product with increased reliability at a lower manufacturing cost.Master of Science
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Davidson, Andrew John. "High voltage breakdown in the Ramsey cell of the CryoEDM experiment : an experimental study of some relevant parameters." Thesis, University of Sussex, 2013. http://sro.sussex.ac.uk/id/eprint/44797/.
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A pressure cell apparatus has been designed, constructed and commissioned to measure the dielectric strength of liquid helium as a function of pressure for various temperatures in He I and He II. Breakdown experiments between a set of stainless steel parallel plate Rogowski profile electrodes with a separation of 1.27 mm have been made for temperatures ranging between 1.7 K to 4.2 K and applied pressures of SVP to ~ 2.2 bar. All pressure data taken above and below the λ-point exhibit similar features. At low pressure, near the SVP, breakdown voltage rapidly increases with applied pressure. This behaviour is linear for all temperatures and has an average gradient of 0.176 ± 0.0096 kVtorr-1. This regime changes at a pressure dependant kink point. Above this point a more gradual increase in breakdown voltage with pressure is observed. Data for all temperatures normalised to 50 kV and 1200 torr have an average gradient of 0.01693 ± 0.00092 kVtorr-1 with an average intercept of 29.69 ± 0.88 kV. A linear relationship is observed between the normalised kink pressure and the density of the helium (-34.4 ± 1.4 kg m-3torr-1 and intercept of 5130 ± 200 kg m-3). The normalised kink pressure as a function of SVP produces a linear relationship with a gradient consistent with unity (0.97 ± 0.04 torr2 with an intercept of 88 ± 13 torr). High voltage breakdown initiating at the cathode triple junction (CTJ) has been investigated in He I, He II and LN2 under SVP. Breakdown tests were made between parallel plate Rogowski profile electrodes with an Al2O3 ceramic spacer between them. Chips, cracks and tracks across the ceramic have been observed. LN2 breakdown tests cause catastrophic damage. Calculations of the E-fields in any gap between the ceramic and electrode show E-field enhancements of up to a factor of ~ 4.5. The end of a ceramic sample was sputtered with Gold in an attempted to prevent any E-field in the gap. This work has been carried out within the UK CryoEDM Collaboration and was aimed at understanding better the parameters which will ultimately limit the E-field in the Ramsey Cell of the main experiment.
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Norgard, Peter. "Development of a gigawatt repetitive pulse modulator and high-pressure switch test stand and results from high-pressure switch tests." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4584.
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Thesis (M.S.)--University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 22, 2009) Includes bibliographical references.
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Saadati, Hassan [Verfasser]. "Partial Discharge and Breakdown of Solid Dielectrics under AC, DC, and Combined AD/DC High Voltage Stresses / Hassan Saadati." Garbsen : TEWISS - Technik und Wissen GmbH, 2020. https://www.tewiss-verlag.de/.
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Liu, Qiang. "Electrical performance of ester liquids under impulse voltage for application in power transformers." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/electrical-performance-of-ester-liquids-under-impulse-voltage-for-application-in-power-transformers(3702b3a2-ec5f-4674-ab11-1032906e8c0c).html.
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Ester liquids including both natural ester and synthetic ester are being considered as potential alternatives to mineral oil, due to their better environmental performance and for some liquids their higher fire point. Although these liquids have been widely used in distribution and traction transformers, it is still a significant step to adopt ester liquids in high-voltage power transformers because the high cost and severe consequence of a factory test failure and the high level of safety and reliability required in service for these units, tend to lead to a cautious approach to any step change in technology. Lightning impulse strength as basic insulation level is of importance for insulation design of power transformers and lightning impulse test is commonly required in the factory routine tests for high-voltage power transformers, so this thesis is aimed to investigate the electrical performances including pre-breakdown and breakdown of natural ester and synthetic ester under impulse voltage. Two types of field geometry were considered in the study, one is sphere-sphere configuration which represents the quasi-uniform fields inside a transformer and another is strongly non-uniform point-plane configuration which represents the situation of a defect or a source of discharge. In quasi-uniform field study, standard breakdown tests were carried out under negative lightning and switching impulse voltages. Influence of various testing methods on the measured lightning breakdown voltage was studied and the 1% lightning withstand voltage was obtained based on Weibull distribution fitting on the cumulative probability plot built up using the approximately 1000 impulse shots. As for strongly non-uniform field study, streamer propagation and breakdown event in ester liquids either with or without pressboard interface were investigated at various gap distances under both positive and negative lightning impulse voltages. A relationship between the results under lightning impulse and previously published results under step voltage was built up to predict the lightning breakdown voltage of ester liquids at very large gaps. The results indicated that impulse strengths of ester liquids for both breakdown and withstand in a quasi-uniform field, are comparable to those of mineral oil. In a strongly non-uniform field, streamers in ester liquids propagate faster and further, than in mineral oil at the same voltage level. Thus breakdown voltages of ester liquids are generally lower than those of mineral oil, which could be as low as 40% at a large gap distance of approximately 1000 mm. Introduction of parallel pressboard interface has no influence on the streamer propagation and thus does not weaken the breakdown voltage, but it tends to reduce the acceleration voltage particularly for mineral oil under positive polarity. Last but not least, a unique phenomenon of secondary reverse streamer (SRS) was observed in ester liquids, which occurs subsequently and well after the extinction of the primary streamer (PS) propagation within a single shot of impulse voltage and has the reverse polarity to the PS. The formation mechanism of SRS is explained mainly due to the reverse electric field induced by the residual space charges left by the PS.
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Toufani, Kamran. "Experimental studies of breakdown characteristics of SF¦6/CF¦4 mixtures in highly non-uniform fields for high-voltage applications." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq23532.pdf.
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Fulper, Jacob C. "THE EFFECTS OF SWITCHING IMPULSES ON THE PARTIAL DISCHARGE ACTIVITY AND BREAKDOWN VOLTAGE OF 15 KV XLPE AND EPR CABLES." MSSTATE, 2009. http://sun.library.msstate.edu/ETD-db/theses/available/etd-11052009-131823/.
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A growing trend in the electrical industry is to move away from overhead lines and towards underground distribution. The cables necessary for underground distribution are stressed in various ways, and one of the most ignored stresses is that of overvoltage caused by switching. The focus of this research is to determine the effects that high voltage switching impulses have on the electrical strength of medium voltage cable insulation. Accelerated aging was performed on multiple samples of XLPE and EPR cables by applying multitudes of switching impulses. At various stages of the aging process, partial discharge measurements were taken. At the end of the aging process, the ac breakdown voltage of each cable sample was determined. While more testing is necessary to gain a greater understanding of this subject, the results obtained in this study show that switching impulses weaken cable insulation, which may lead to premature failure of distribution cables.
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Buono, Benedetto. "Simulation and Characterization of Silicon Carbide Power Bipolar Junction Transistors." Doctoral thesis, KTH, Integrerade komponenter och kretsar, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-95320.
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The superior characteristics of silicon carbide, compared with silicon, have suggested considering this material for the next generation of power semiconductor devices. Among the different power switches, the bipolar junction transistor (BJT) can provide a very low forward voltage drop, a high current capability and a fast switching speed. However, in order to compete on the market, it is crucial to a have high current gain and a breakdown voltage close to ideal. Moreover, the absence of conductivity modulation and long-term stability has to be solved. In this thesis, these topics are investigated comparing simulations and measurements. Initially, an efficient etched JTE has been simulated and fabricated. In agreement with the simulations, the fabricated diodes exhibit the highest BV of around 4.3 kV when a two-zone JTE is implemented. Furthermore, the simulations and measurements demonstrate a good agreement between the electric field distribution inside the device and the optical luminescence measured at breakdown. Additionally, an accurate model to simulate the forward characteristics of 4H-SiC BJTs is presented. In order to validate the model, the simulated current gains are compared with measurements at different temperatures and different base-emitter geometries. Moreover, the simulations and measurements of the on-resistance are compared at different base currents and different temperatures. This comparison, coupled with a detailed analysis of the carrier concentration inside the BJT, indicates that internal forward biasing of the base-collector junction limits the BJT to operate at high current density and low forward voltage drop simultaneously. In agreement with the measurements, a design with a highly-doped extrinsic base is proposed to alleviate this problem. In addition to the static characteristics, the comparison of measured and simulated switching waveforms demonstrates that the SiC BJT can provide fast switching speed when it acts as a unipolar device. This is crucial to have low power losses during transient. Finally, the long-term stability is investigated. It is observed that the electrical stress of the base-emitter diode produces current gain degradation; however, the degradation mechanisms are still unclear. In fact, the analysis of the measured Gummel plot suggests that the reduction of the carrier lifetime in the base-emitter region might be only one of the causes of this degradation. In addition, the current gain degradation due to ionizing radiation is investigated comparing the simulations and measurements. The simulations suggest that the creation of positive charge in the passivation layer can increase the base current; this increase is also observed in the electrical measurements.QC 20120522
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Jaoul, Mathieu. "Study of HBT operation beyond breakdown voltage : Definition of a Safe Operating Area in this operation regime including the aging laws." Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0029.
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Le développement de nouvelles filières BiCMOS permettra, grâce aux améliorations technologiques apportées aux TBH (Transistor Bipolaire à Hétérojonction) SiGe:C, d’atteindre des performance dynamiques au-delà de 0.5 THz. Un aspect important doit être investigué : il s’agit de l’aire de sécurité de fonctionnement (SOA : Safe operating area) au-delà du classique BVCEO. En effet, de par la complexité des futures architectures de TBH(comme la B55X de chez STMicroelectronics) et de par leur taille nanométrique, il est attendu une augmentation des effets physiques présents dans ces transistors. Par ailleurs,en raison de la dépendance croissante de la conception de circuits vis-à-vis des outils logiciels, on s’attend à devoir développer des efforts supplémentaires pour concevoir des modèles compacts davantage prédictifs. Ainsi, le sous-projet SOA est conçu pour décrire l’aire de sécurité de fonctionnement des TBH SiGe :C de taille nanométrique en vue de son intégration dans le modèle compact en tenant compte des aspects critiques.Dans le premier chapitre, une description précise des régimes de fonctionnement au delà de la tension de claquage BVCEO est développée. Le modèle compact HICUM est amélioré pour prendre en compte les mécanismes se produisant dans cette région afin de modéliser précisément le phénomène d’avalanche et l’effet de focalisation du courant au centre de l’émetteur. Une validation de ce nouveau modèle est réalisée au travers de simulations TCAD mais aussi par des caractérisations électriques de différents TBH de tailles variées et pour de multiples températures.Dans le second chapitre, le comportement des transistors bipolaires proche des limites de fonctionnement a été étudié. Une étude de l’effet de focalisation du courant et du phénomène de “snapback” est réalisée pour en définir précisement les limites de fonctionnementà forts courants et tensions et une zone de stabilité est définie.Dans de troisième chapitre, le vieillissement accéléré de TBH est réalisé pour des régimes de fonctionnement aux frontières de la zone de sécurité de fonctionnement. Un modèle de vieillissement est alors développé pour prendre en compte les mécanismes d’usure se produisant dans ces régimes de fonctionnement.En conclusion, ce travail a permis de modéliser de manière précise les TBH SiGe àforts courant et tensions tout en prenant en compte les mécanismes d’usure se produisant dans ces régimes de polarisationThe development of new BiCMOS technology will be possible, thanks to the SiGe:CHBTs technological improvements to reach dynamic performance beyond 0.5 THz. Animportant aspect to be investigated is the Safe Operating Area (SOA) beyond the traditionalBVCEO. In fact, due to the complexity of future architectures of HBTs (likethe B55X from STMicroelectronics) and their nanoscale size, an increase of the wear-outmechanisms occurring in these transistors is expected. In addition, because of the increasingdependence of circuit design on software tools, it is expected that additional effortswill be required to develop more predictive compact models. Thus, the SOA sub-projectis designed to describe the functional safety area of nanoscale SiGe:C HBTs allowing thecompact model to take into account critical aspects.After a short introduction, a precise description of the transistor operations beyondthe breakdown voltage is detailed in the second chapter. The compact model HICUM isimproved to account for the mechanisms occurring in this region to accurately model theavalanche regime and the pinch-in effect. This new model is validated on TCAD simulationsand through electrical measurements on different devices, architecture, geometriesand temperatures.In the third chapter, the investigation is deepen towards the device border’s operation.A study of the pinch-in effect and the snapback behavior is therefore realized to understandthe operation limitations at high currents and voltages and a stable operation regime isintroduced.In the fourth chapter, accelerated aging tests are carried out at the boundaries of thesafe operating area to submit the transistor to thermal and hot carriers stresses during itsoperation. An aging model is developed to account for the wear-out mechanism occurringin that regime.To conclude, this work allowed to increase the modeling of SiGe HBTs at high voltagesand currents accounting for the wear-out mechanisms occurring in that operation regime
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Nobeen, Nadeesh. "Design and reliability of polymeric packages for high voltage power semiconductors." Thesis, Loughborough University, 2011. https://dspace.lboro.ac.uk/2134/8957.
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This thesis focuses on the development of a novel polymer based housing for power thyristor devices typically used in long distance high voltage direct current (HVDC) transmission. Power thyristor devices used in HVDC power conversion stations are typically packaged in a hermetically sealed ceramic housing and have demonstrated an excellent history of reliability and performance. However, to avoid increasing the number of thyristors in future higher powered HVDC schemes thyristors having higher power ratings at 8.5 kV and sizes at 125 mm and 150 mm diameters are sought for implementation to achieve higher transmission ratings of, for example, 4000 A at +/- 800 kV. The main disadvantages of such large ceramic-based packages are higher processing cost and weight whilst robustness is also a concern. To overcome these issues, replacing the current ceramic housing with a polymeric material has been investigated in this project. The advantages it is anticipated such packages will provide include lower cost, less weight, robustness, recyclability, etc. However, some challenges it will also offer are: non-hermeticity i.e. polymers are moisture and gas permeable, potentially more complex manufacturing routes, and different electrical, mechanical and thermal properties compared to ceramic materials. The work presented in this thesis was part of a larger project where these challenges have been addressed by developing and testing a prototype polymeric thyristor housing. The prototype is aimed at demonstrating that polymer packages can deliver performance and reliability comparable to, if not better than, current ceramic packages. In this thesis, it is the package development and reliability related studies that are discussed. Because the housings will experience severe electrical stresses and various thermal excursions during their service life, the electrical and thermo-mechanical behaviour of the polymer housing was studied using finite element analysis to gain an understanding of the effects of various design variables and materials properties on performance and the tradeoffs between performance and manufacturability. From these modelling studies, design guidelines have been established for the future development of polymer housings. On the other hand, to identify the physics-of-failure of the prototype that was manufactured as part of the project, accelerated life tests were performed to study its reliability. The knowledge gained from the polymer prototype development was then applied to the design of a larger 125 mm diameter housing using the Taguchi method of experimental design.
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Jaberansari, Ahmad. "The variation of breakdown voltage with temperature for several low-flammability transformer fluids and building of an optimal design using one fluid." Thesis, University of Salford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303754.
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Ehlers, Richard. "Determining the switching impulse breakdown voltage over large air gaps with an application to tower-conductor window configurations." Thesis, 1998. http://hdl.handle.net/10539/22712.
Full textAbstract:
A dissertation submitted to the Faculty of Engineering,
University of the Witwatersrand, in fulfilment of the
requirements for the degree of Master of Sclenice in
Engineering
February 20th, 1998All available model used to determine the 50% breakdown voltage for rod-type ami conductor-type gaps subject to switching is impulse wave forms has been applied to a tower-conductor window gap configurution. The results for rod-plane, conductor-piane and tower-conductor window gaps have all been compared and correspond well with practical data. III order to app(v the model, a charge simulation technique has been adopted ill conjunction with the 'Coulomb 3D' charge simulation package. Additional tests have been performed where parameters of'the charge simulation method am! the electrode geometl:p hare been adjusted and consequent conclusions made. Recommendations for further application of tile model have been suggested.
MT2017
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Chen, Yeong-Jia, and 陳永嘉. "High breakdown voltage doubleδ-doping InGaP/InGaAs HFETs." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/61878494949631972955.
Full textAbstract:
碩士國立成功大學
電機工程學系
88
In this thesis, the doubleδ-doping InGaP/InGaAs heterojuction field-effect transistors (HFET) have been successfully fabricated by low-pressure metalorganic chemical vapor deposition ( LP-MOCVD ) system. There is a large conduction band discontinuity (ΔEc) between InGaP and InGaAs and then the electrons in the channel would be confined well. Furthermore, InGaP has a wide bandgap (~1.92eV) and hence can be used to fabricate high breakdown voltage devices. High gate-to-drain breakdown voltage surpasses 60V in our studying structure. This high breakdown voltage is suitable for high power application. The maximal transconductance is 61mS/mm and the saturation drain current density is about 125mA/mm with a gate geometry 1.5´125 mm2 at 300K. The maximal extrinsic transconductance is 86mS/mm at 77K. In addition, the AlGaAs barrier layer creates an energy barrier in the conduction band to reduce electron injection into the buffer and we can obtain better pinch-off characteristic. The voltage gain as high as 71 was found. Therefore, the device has amplification capability
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Hsieh, Yu-En, and 謝於恩. "Analysis of short-channel power device breakdown voltage." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/68808087731263493805.
Full textAbstract:
碩士國立勤益科技大學
電子工程系
101
Power device plays an important role in the development of technology. Everyday electronic device such as PCs, smartphones and power-saving LED always used Power devices. The design of the power device in this research can be used for devices that require 90nm and 130nm, which is suitable for consumer electronic products. It is also an important direction for the development of future power component design. In this paper, a small power component designed to explore the basis. First, the differences in aspect ratio of the STI produce different power components. Then the length of the narrow channel power components to produce 90nm power components, and comparative analysis of the different structure of the STI process breakdown voltage characteristics. However, due to the limit of current manufacturing technology and the voltage withstandability of the 130 nm power component, there is not a very well integrated production process. According to TSMC’s website, the 130 nm and 90 nm BCD technology is still under development. In this paper, first explore the next generation 90-nanometer technology issues in order to provide the future process improvements. In this paper, the design of the drift region and the STI design are consistent with the current semiconductor manufacturing technology. All processes used by national laboratories also modeled the machine parameters. So the simulation process, will be the development and design of components used. This paper also found that the industry can’t properly produce the main production. Channel length of 90 nm power components, production often because of the pressure can’t be controlled drift region and the gate oxide layer can withstand high pressure problem. In this paper, the breakdown voltage drift region and present its analysis of the problem.
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Patnaik, Akash. "Breakdown Voltage Analysis of High Electron Mobility Transistor." Thesis, 2018. http://ethesis.nitrkl.ac.in/9646/1/2018_MT_216EE1273_APatnaik_Breakdown.pdf.
Full textAbstract:
Since the invention of the metal-oxide-semiconductor field-effect-transistor (MOSFET), the
semiconductor industry for electronics has been dominated by silicon (Si). The reason being the cost and ease of creating a native oxide on Si which enables the well established complementary metal-oxide-semiconductor (CMOS) process which has revolutionised the digital world we live in. Si, however,is a low band gap material (1.1 eV) and although used in power semiconductor sector over the years, new materials with superior properties are being investigated as potential replacements especially in power sector.Since past three decades, power management efficiency and cost have shown steady improvement as innovations in power MOSFET structures, technology, and circuit topologies have paced the
growing need for electrical power in our daily lives. In the last few years, however, the rate of improvement has slowed as the silicon power MOSFET has approached its theoretical bounds. Due to the limitations reached by silicon devices, new materials are emerging to cater the needs of today’s scenario. The prominent being the Gallium Nitride based High Electron Mobility Transistors.
GaN based devices have superior performance in field of power electronics as well as in many high frequency applications. This is due to its characteristic property of large bandgap,leading to high breakdown field and high mobility,allowing it to be used in high frequency applications. In the field of power converters two key power-switch requirements are there: (1) high blocking voltage with as small as possible resistance of the drift region that supports the blocking voltage and (2) high switching speed. Silicon based MOSFET have limitations of low breakdown voltage, high on resistance and low switching frequency. On contrary GaN based HEMT have high breakdown voltage capacity along with high switching speed which makes it far beyond its competitor, silicon based devices.
In this paper, breakdown voltage analysis is done and various aspects of improving the breakdown voltage are studied. On a specific note, detailed study on effect of passivation layer on breakdown voltage is done,considering structure miniaturisation, reduced on -resistance, high blocking voltage and high switching frequency. Moreover, passivation layer addition has multipurpose role in GaN based HEMT viz. removal of current collapse,protection to device, increment of breakdown voltage etc. Results from this study show electric field modification as the dielectric constant is increased. This modification is in terms of electric field distribution beneath gate-drain region especially at the drain edge of the gate. This lowering of electric field, as a result of distribution,helps in significant increment of breakdown voltage along with removal of current collapse. It is also observed that when pas sivation thickness is increased, breakdown voltage also increases.
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Chang, Chin-Hong, and 張欽鴻. "Split Buried Layer Structure for Increasing Breakdown Voltage in High-Voltage CMOS Design." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/01566260819797362115.
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Chang, Chih-Kuo, and 張致國. "Dielectric Electroactive Polymers at Breakdown Voltage State and Reversibility." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/79739384014471407592.
Full textAbstract:
碩士國立臺灣大學
機械工程學研究所
99
Recently, there has been growing interest in actuators by using dielectric electroactive polymers, DEAPs due to their attractive properties of mechanism, low cost and high dielectric constant. However, operating characteristics of DEAPs are affected by applied voltage and the size of DEAPs. With increases applied voltage, because of increasing electric force, compliant electrodes of actuator are gradually close to each other. If the thickness of DEAPs decreases, applied voltage can be lower and reliability can be improved. The researches of reliability are important issues today. In our experiments, we focus on and discuss breakdown phenomenon, pull-in effect and reversibility of DEAPs material. In the experiment, we apply a DC voltage to DEA actuator and observe the alterations of displacement and current with time and the increase of applied voltage. In our results, it was found that the largest current is observed by computer when applied voltage is 2000V. This result signifies that breakdown phenomenon occurs at this time. According to discriminant of condition, breakdown phenomenon occurs before pull-in effect occurs. Meanwhile, with the increase of applied voltage from 0V to 1600V and then, decreases to 0V, we observe the reversibility of DEA material and also discuss its hysteresis. In addition, the mechanical-electrical coupling model for DEAPs is also successfully investigated by electrostatic analysis and hyper-elastic stress analysis.
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Lin, Pei-ying, and 林佩瑩. "Analysis of AlGaN/GaN High Breakdown Voltage Schottky Diodes." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/98253923560566605289.
Full textAbstract:
碩士國立中央大學
電機工程研究所
98
In this study, AlGaN / GaN HEMT structures on the high-resistance AlN buffer layer and the conventional GaN buffer layer were grown, respectively. The planar Schottky diodes were then fabricated on these structures. From the I-V measurement, the results indicate the device with high-resistance AlN buffer layer not only substantially promote the breakdown voltage but also keep the low leakage current density. Therefore, in this study we discussed in detail about the factors of SBDs characteristics on different buffer layers, and further analyzed the mechanism of leakage current. In the analysis of material quality, according to the x-ray diffraction GaN (002) rocking curve shows that AlN buffer layer can effectively reduce the screw-type dislocation density of epitaxial materials, thus reducing the leakage current. Besides, the etching pits density (EPD) is also calculated that the dislocation density of the above epitaxial structure reduced to about 3.2x107 cm-2, which is about an order lower compared to the epitaxial material grown on the GaN buffer layer. In the analysis of leakage current, the leakage current in the buffer layer and the AlGaN barrier layer are discussed, respectively. In the discussion, the resistance of the AlN buffer layer is about six orders greater than that of the GaN buffer layer, indicating that the AlN buffer layer has the characteristic of low-leakage current; in addition, temperature-dependent current-voltage (I-V) measurement and frequency-dependent capacitance-voltage (C-V) measurement are used to analyze the mechanism of leakage current. The results show that the primary source for the leakage current during the voltage of 0 V~ - 6 V is the AlGaN barrier layer while the leakage current is dominated by the quality of buffer layer below -6 V. To further discussion, defect energy levels in AlGaN barrier are quantified by the leakage current model of Frenkel-Poole emission (F-P emission).
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Lai, Wei-Hsi, and 賴韋錫. "Optimization of breakdown voltage and substrate current in MOSFETs." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/39945251738661675974.
Full textAbstract:
碩士國立交通大學
工學院碩士在職專班半導體材料與製程設備組
98
With the progress of integrated circuit technology , high-voltage devices with high power have developed into the market of HV-MOSFETs from the market of thyristors and bipolar power transistors ,which have become the most preferable devices to be integrated with the technology of conventional CMOS due to its low cost, fast switching speed, and low power loss. Hence, HV-MOSFETs are mostly-applied to not only control but also carry the high power ICs with high current nowadays. Integrating high power devices with low power circuit is an important in the marketing of electronic application. The Double-Diffusion Drain MOS ( DDDMOS ) is the first device structure proposed to sustain high drain voltage. DDDMOS is still the first choice for devices operating at low voltage due to its simple process. In this thesis, we focus on the impact of ion implantation condition of original process and extra implantation process on the performance of DDDMOS. Using TCAD simulation tools,it is observed that with the increase of implantation energy, the breakdown voltage increases and the snapback issue is relaxed. However, the saturation current will be degraded due to the formation of non-converted p-type region on the drain surface. If the implant dosage is increased, the quasi-saturation phenomenon at high gate voltage, the driving capability, and the turn-off leakage are all improved, but the breakdown voltage would be degraded, and increase substrate current. So we add the extra surface implantation process to improve the substrate current. These results imply that implantation dose and energy might be the better choice.On the basis of TCAD simulation, the implantation energy was raised to 400 KeV and the implantation dose was changed to 6.3×10^12cm-2 and extra surface implantation energy was 50 KeV and the implantation dose was 1.4×10^12cm-2 .A 10% increase of breakdown voltage and 34% reduction of turn-off current were obtained. Meanwhile the 77% reduction of substrate current was observed due to the extra implantation process. It is expected that with higher energy and dose device performance can be improved furthermore.
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Chen, S. H., and 陳世宏. "the study of high breakdown voltage InGaP channel MESFETs." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/61834530450369485307.
Full textAbstract:
碩士國立交通大學
材料科學與工程系
90
Abstract A high breakdown voltage InGaP channel metal-semiconductor field-effect transistor ( MESFET ) has been developed in this study. The device is designed for the high output power amplifier application for wireless communication. The DC characteristics of the InGaP MESFETs and the GaAs MESFETs were measured. For the InGaP MESFETs, the device exhibited a saturation current density of 108 mA/mm with a gate to drain breakdown voltage of 55 volts. The maximum transconductance gm of the device was 36 mS/mm, and the pinch-off voltage was —5 volts. On the other hand, the GaAs MESFETs exhibited a saturation current density of 200 mA/mm with a gate-drain voltage of 39 volts. The maximum transconductance gm of the device was 98 mS/mm, and the pinch-off voltage was —1.6 volts. The fabrications of InGaP MESFETs and GaAs MESFETs were successful. The high band-gap InGaP channel metal-semiconductor field-effect transistor has a high breakdown voltage and it could be used for the high power amplifier application. The InGaP channel MESFETs developed has a good potential for the application in the power amplifier for wireless communication.
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Jiang, Huan, and 江瓛. "Breakdown Voltage of Metal-Oxide-Semiconductor Field-Effect Transistors." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/75543026803172223906.
Full textAbstract:
碩士國立暨南國際大學
電機工程學系
103
Unlike conventional MOSFETs, power MOSFETs requires high breakdown voltages to operate in integrated circuits. Using two-dimensional TCAD simulations, this thesis explores the breakdown voltage and associated mechanism of power MOSFET devices. Ideally one-dimensional PN junctions are first simulated to realize the effects of doping concentration and junction length on breakdown voltage, and subsequently, lightly doped drain MOSFETs are investigated to study the distribution of electrical field and voltage drop across the lightly doped drain region. Finally, the lateral diffused MOSFETs (LDMOS) are extensively examined to design the drift region for improving the breakdown voltage while retaining a minimized drift area.
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Chen, Yen-Wei, and 陳彥瑋. "High Breakdown Voltage InGaP/InGaAs/AlGaAs High Electron Mobility Transistors." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/81726860258089375795.
Full textAbstract:
碩士國立成功大學
電機工程學系
88
In this thesis, the high breakdown InGaP/InGaAs/AlGaAs high electron mobility transistor (HEMT) grown by low-pressure metalorganic chemical vapor deposition (LP-MOCVD) has been fabricated and demonstrated successfully. By using the high-bandgap InGaP Schottky layer and the pseudomorphic InGaAs channel, we can get high breakdown voltage (63V) and low-leakage current (＜40mA/mm). The maximum extrinsic transconductance is 81mS/mm and the maximum saturation drain current density is 258mA/mm. By using the wet chemical etching technique of thinning the undoped InGaP Schottky layer the device performances can be improved and we can also obtain enhancement-mode HEMT. The results show that the extrinsic transconductance can be improved and the breakdown voltage is still large (>40V). We can offer a very good tradeoff between high extrinsic transconductance and high breakdown voltage. On the other hand, we also discuss the breakdown voltage of different temperature.
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WONG, CYUN-SIANG, and 翁群翔. "High Breakdown Voltage Enhancement-mode Double-channel AlGaN/GaN HEMTs." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/85524946293443335561.
Full textAbstract:
碩士國立雲林科技大學
電子工程系
104
In this thesis, simulation and improvement of dual-channel AlGaN/GaN HEMTs by using Sentaurus TCAD is reported. Due to the energy gap difference between AlGaN and GaN, a quantum well is formed at the interface. Electrons are moved by the polarization effect and accumulated at the quantum well, forming 2DEG in the channel even when the gate bias is not applied. Therefore, the HEMTs become depletion mode. In circuit applications, depletion-mode transistors requires a negative supply voltage, which makes the circuit more complicate. As a result, development of enhancement-mode AlGaN/GaN HEMTs is highly desirable. The challenge in designing an enhancement-mode dual-channel HEMT is that it is much more difficult to deplete the electrons in the lower channel. In this work, a variety of techniques are integrated, including adjusting the thickness of AlGaN layer, using recessed gate, applying partial p-type doping, and replacing the GaN buffer layer with an AlGaN buffer layer. The result is two structures of enhancement-mode HEMTs, both of which have very low drain leakage current. Then one of the structures is chosen to improve the off-state breakdown voltage. Conventional gate field plate and slant gate field plate are incorporated and optimized respectively. Moreover, the effects of field plate length and passivation layer thickness are analyzed and compared.
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Tseng, Chih-Kuo, and 曾治國. "High Speed and Low Breakdown Voltage Germanium Silicon Avalanche Photodetectors." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/05073572147157453145.
Full textAbstract:
博士國立清華大學
光電工程研究所
101
A low breakdown voltage Ge/Si avalanche photodetector (APD) was demonstrated using a separated multiplication and absorption structure with lateral Si avalanche pin and vertical Ge/Si pin. Because the process condition is compatible with standard CMOS process, it is potential to be integrated with other electronics and Si photonics and applied for high-performance optical receivers
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Ming-YuCheng and 鄭閔友. "Study of high breakdown voltage AZO/Si Schottky barrier diodes." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/urzx9m.
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Chang, Alex, and 張智毅. "Electrostatic Discharge on Breakdown Voltage and Damage of Gate Dielectric in MOSFET's." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/03417125115660738198.
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WANG, CHIEN-MIN, and 王建閔. "Improving breakdown voltage for AlGaN/GaN HEMTs with a dual-gate structure." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/qwp3hm.
Full textAbstract:
碩士國立雲林科技大學
電子工程系
105
In high-electron mobility transistors (HEMTs), a quantum well is formed at the heterointerface and electrons accumulate in the intrinsic low-bandgap material, so the electron mobility is high. AlGaN/GaN HEMTs are suitable to high-power applications due to high breakdown field in the materials. The double-gate structure can also improve breakdown voltage of the device , as well as output power and high-frequency characteristics. However, the effect of the gate 2 bias on the breakdown has not been studied. This thesis summarizes the procedure of changing a depletion-mode (D-mode) double-channel AlGaN/GaN HEMT into enhancement-mode (E-mode), improving its Gm-VGS characteristic, and finally adding a second gate to increase the breakdown voltage. The bias of gate 2 is optimized.
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Liao, Yu-Chieh, and 廖御傑. "The Root Cause and Improvement of GIDL Breakdown in High Voltage nMOSFETs." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/07630715712518129716.
Full textAbstract:
碩士國立交通大學
工學院半導體材料與製程設備學程
100
A gate-induced-drain-leakage-induced OFF-state breakdown is examined in our high-voltage depletion-mode n-channel metal–oxide–semiconductor field-effect transistors. By increasing the dosage in the n-region, a bell-shaped trend between the OFF-state breakdown voltage VBD and the dosage in the n-region is observed.Such a bell-shaped trend is found to result from two competing factors: an electric field in the gate edge and an electric field associated with the drain–bulk junction. The latter electric field is responsible for the falling part in the bell-shaped trend. Our model can explain the data of the slightly bell-shaped trend between OFF-state VBD and implant energy in the n-region. Additionally, the effect of Si recess variation on OFF-state VBD variation can be understood from our model. According to our model, approaches to improve OFF-state VBD and the effect of Si recess variation on VBD variation are proposed. Base on the thesis results, no mater the improvement of off state breakdown or the impact of process variation all can be controlled in our experiment results.
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Huang, Jing Wen, and 黃靖文. "Gd2O3/La2O3 of High Breakdown Voltage GaN HEMT with Field-Plate Technology." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/10577731565006749369.
Full textAbstract:
碩士長庚大學
電子工程學系
99
Gallium nitride is a binary III / V direct bandgap semiconductor. It’s wide band gap of 3.4 eV, high-power and high-frequency devices. GaN can work at much hotter temperatures and run at much higher voltages than gallium arsenide transistors. They are perfect materials for power amplifiers at microwave frequencies. The high breakdown is 140V of La2O3. On the other hand, Gmax is 132mS/mm of La2O3. The paper consists of several parts : introduction, analysis materials and current characteristic for oxide layers (Gd2O3/La2O3), electrostatic discharge test, and so on. We implanted different oxide layers on GaN. In this case, we’re particularly interested in improving the power performance by inserting the thin lanthanum/gadolinium oxide layer on the bottom of conventional Ni/Au gate in AlGaN/GaN HEMT fabrication. The dielectric constant of Gd2O3/La2O3 are about 21.49/30.45 which provide a high channel control ability in FET. Study on measurement of results and ESD. We found gold plating process, the ESD damages could be prevented.
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Lin, Zong-Ru, and 林宗儒. "Ultra-High Breakdown Voltage Design Thin Film Transistors by Asymmetric Multi-gates." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/71526293566224201560.
Full textAbstract:
碩士逢甲大學
電子工程學系
101
Polycrystalline silicon thin film transistors (poly-Si TFTs) have been widely applied in electronic products such as active-matrix liquid crystal displays (AMLCD) systems, pixel switches, and peripheral driver circuits due to their high field-effect mobility compared with amorphous silicon (a-Si) TFTs. This device is a promising candidate to be used in the display system-on-panel (SOP) as a controller and memory. However, this device experiences a high electric field near the channel/drain junction region. The high electric field is the major cause of impact ionization in that area, which causes a serious kink effect in the output characteristics. The kink effect is a serious problem that increases the power dissipation and degrades the switching characteristics when poly-Si TFTs are employed in digital circuits, while in analogic circuit application, it reduces the maximum attainable gain and the common mode rejection ratio. Recently, the dual-gate structure have been proposed and investigated to suppress the kink effect, and slightly improved the breakdown voltage. However, the results of conventional dual-gate device still can’t achieve our expectation. In this study, an AMG-TFT is proposed to improve the breakdown voltage greatly and raised the on-state current. Our proposed TFT derives a desired breakdown voltage or on current from systemic analytic results, and it also employs multi-gates for suppressing the parasitic bipolar effect. The simulation shows that drain voltage can be extended to reach the doped (N+) region, when the hole carriers which is caused by impact ionization accumulates incessantly in the channel to induce low resistance region. Because of this, the effective channel length is also reduced to increase the saturate current. For this reason, the breakdown voltage and on-state current of our proposed structure are all better than the conventional Poly-Si TFT.