To see the other types of publications on this topic, follow the link: Conduction Fowler-Nordheim.
Journal articles on the topic 'Conduction Fowler-Nordheim'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Conduction Fowler-Nordheim.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Fiorenza, Patrick, Marilena Vivona, Ferdinando Iucolano, Andrea Severino, Simona Lorenti, and Fabrizio Roccaforte. "Temperature-Dependence Study of the Gate Current SiO2/4H-SiC MOS Capacitors." Materials Science Forum 924 (June 2018): 473–76. http://dx.doi.org/10.4028/www.scientific.net/msf.924.473.
Full textAbstract:
We present a temperature-dependence electrical characterization of the oxide/semiconductor interface in MOS capacitors with a SiO2layer deposited on 4H-SiC using dichlorosilane and nitrogen-based vapor precursors. The post deposition annealing process in N2O allowed to achieve an interface state density Dit 9.0×1011cm-2eV-1below the conduction band edge. At room temperature, an electron barrier height (conduction band offset) of 2.8 eV was measured using the standard Fowler-Nordheim tunneling model. The electron conduction through the SiO2insulating layer was evaluated by studying the experimental temperature dependence of the gate current. In particular, the Fowler-Nordheim electron barrier height showed a negative temperature coefficient (dφB/dT= - 0.98 meV/°C), which is very close to the expected value for an ideal SiO2/4H-SiC system. This result, obtained for deposited SiO2layers, is an improvement compared to the values of the temperature coefficient of the Fowler-Nordheim electron barrier height reported for thermally grown SiO2. In fact, the smaller dependence ofφBon the temperature observed in this work represents a clear advantage of our deposited SiO2for the operation of MOSFET devices at high temperatures.
2
Sometani, Mitsuru, Dai Okamoto, Shinsuke Harada, et al. "Conduction Mechanism of Leakage Current in Thermal Oxide on 4H-SiC." Materials Science Forum 778-780 (February 2014): 579–82. http://dx.doi.org/10.4028/www.scientific.net/msf.778-780.579.
Full textAbstract:
The conduction mechanism of the leakage current in thermal oxide on 4H-SiC was identified. The carrier separation current-voltage method clarified that electrons are the dominant carriers of the leakage current. The temperature dependence of the currentvoltage characteristics indicated that the conduction mechanism of the leakage current involved not only Fowler-Nordheim tunneling (FN) but also Poole-Frenkel (PF) emission. The PF emission current due to the existence of defects in the oxide increased with temperature.
3
CHEONG, K. Y., Z. LOCKMAN, A. AZIZ, et al. "CURRENT CONDUCTION MECHANISMS OF ATOMIC-LAYER-DEPOSITED Al2O3/NITRIDED SiO2 STACKING GATE OXIDE ON 4H-SiC." International Journal of Modern Physics B 24, no. 27 (2010): 5371–78. http://dx.doi.org/10.1142/s0217979210055925.
Full textAbstract:
Current conduction mechanisms of atomic-layer deposited Al 2 O 3 (13 nm) stacked on different thermal nitrided SiO 2 thicknesses (2, 4, and 6 nm) on n-type 4 H-SiC have been systematically analyzed. It has been observed that the oxides were thermally stable at the investigated temperature range (25–140°C). By using different conduction process models, such as Schottky emission, direct tunneling, Fowler–Nordheim tunneling, Poole–Frenkel emission, and space-charge limited conduction, which consists of three limited conduction processes, namely, Ohm's law, Child's law, and trap-filled limit, the conduction mechanisms of charge through the oxides have been evaluated. It has been found that the conduction mechanisms were not affected by the investigated temperature range. A relationship plot has been proposed among nitrided SiO 2 thickness, electric field, and conduction mechanisms.
4
Yang, Hsin Chia, and Mu Chun Wang. "Evaluation of the Dielectric by Measuring Leakage Currents on Self-Built Capacitor-Like Devices." Advanced Materials Research 204-210 (February 2011): 558–62. http://dx.doi.org/10.4028/www.scientific.net/amr.204-210.558.
Full textAbstract:
In metal-insulator-silicon (MIS) structure, 100 Å Ta2O5films are deposited on 1000 Å doped poly silicon as a bottom electrode layer, followed by 500 Å TiN metal as the top electrode [1]. The measured leakage currents as shown are either temperature dependent as the top electrode is negatively biased or temperature independent as the top electrode is positively biased. Therefore, the mechanism of current conduction is believed to be Fowler-Nordheim tunneling as the top electrode of the capacitor is positively biased. As for the top electrode is negatively biased, the temperature-dependent leakage currents satisfying reasonable arguments about dielectric constant suggest that the most probable conduction mechanism should be attributed to Poole-Frenkel emission.
5
Yamada, Keiichi, Junji Senzaki, Kazutoshi Kojima, and Hajime Okumura. "A Novel Approach to Analysis of F-N Tunneling Characteristics in MOS Capacitor Having Oxide Thickness Fluctuation." Materials Science Forum 858 (May 2016): 433–36. http://dx.doi.org/10.4028/www.scientific.net/msf.858.433.
Full textAbstract:
The new indicators, effective gate oxide thickness tc and effective gate electrode area D, and their combination are applied for a new analysis method of Fowler-Nordheim (F-N) tunneling characteristics in MOS capacitor having oxide thickness fluctuation. This method considering the conduction properties of F-N tunneling characteristics correlates its characteristics to the oxide reliability. These indicators quantified with the influence of the oxide thickness fluctuation can provide the net values of the electric field and the current density on the gate oxide. This new analysis method will lead to reducing the evaluation time for the reliability assessment.
6
Smoliner, J., R. Christanell, M. Hauser, E. Gornik, G. Weimann, and K. Ploog. "Fowler–Nordheim tunneling and conduction‐band discontinuity in GaAs/GaAlAs high electron mobility transistor structures." Applied Physics Letters 50, no. 24 (1987): 1727–29. http://dx.doi.org/10.1063/1.97729.
Full text
7
Irokawa, Yoshihiro. "Characterization of the Metal-Semiconductor Interface of Pt-GaN Diode Hydrogen Sensors." Materials Science Forum 740-742 (January 2013): 473–76. http://dx.doi.org/10.4028/www.scientific.net/msf.740-742.473.
Full textAbstract:
In this paper, interaction mechanism of hydrogen with GaN metal-insulator-semiconductor (MIS) diodes has been investigated, focusing on the metal/semiconductor interfaces. As a result, the following three points are revealed: First, MIS Pt-SiO2-GaN diodes show a marked improvement in detection sensitivity, suggesting that the device interface plays a critical role in sensing. Second, exposure of the diodes to hydrogen is found to change the conduction mechanisms from Fowler-Nordheim tunneling to Pool-Frenkel emission. Third, interface trap level density of the diodes is found to be reduced by hydrogen exposure even at room temperature. These results support the validity of the hydrogen-induced dipole layer model.
8
Tan, Changhua, and Mingzhen Xu. "Correlation between Si–SiO2 heterojunction and Fowler–Nordheim conduction mechanism after soft breakdown in ultrathin oxides." Solid State Communications 139, no. 1 (2006): 23–26. http://dx.doi.org/10.1016/j.ssc.2006.05.008.
Full text
9
Fiorenza, Patrick, Antonino La Magna, Marilena Vivona, Filippo Giannazzo, and Fabrizio Roccaforte. "Anomalous Fowler-Nordheim Tunneling through SiO2/4H-SiC Barrier Investigated by Temperature and Time Dependent Gate Current Measurements." Materials Science Forum 897 (May 2017): 123–26. http://dx.doi.org/10.4028/www.scientific.net/msf.897.123.
Full textAbstract:
This paper reports on the conduction mechanisms and trapping effects in SiO2/4H-SiC MOS-based devices subjected to post deposition annealing in N2O. In particular, the anomalous Fowler-Nordheim (FN) tunnelling through the SiO2/4H-SiC barrier observed under consecutive reverse bias sweeps was studied by temperature and time dependent gate current measurements. The excess of gate current with respect to the theoretical FN predictions was explained by a charge-discharge mechanism of Near Interface Traps (NITs) in the oxide. The gate current transient was described with a semi-empirical analytical model, modifying the standard FN model with a time-dependent electric field to account for the neutralization of trapped charges at NITs.
10
Touati, Amine, Samir Chatbouri, Nabil Sghaier, and Adel Kalboussi. "Theoretical Analysis and Characterization of Multi-Islands Single-Electron Devices with Applications." Scientific World Journal 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/241214.
Full textAbstract:
A two- (2D) and three-dimensional (3D) multiple-tunnel junctions array is investigated. Device structure and electrical characteristics are described. We present a comparison of carriers transport through devices based on polymetallic grains based on master equation and the orthodox theory. The Coulomb blockade effect of 2D and 3D arrays is observed at low and high temperatures. The conduction mechanism is handled by the tunnel effect, and we adopt in addition the thermionic and Fowler-Nordheim emissions. Numerical simulation results focused on flash-memory and photodetector applications. Memory characteristics such as program/erase select gate operation are demonstrated in 2D devices. Also 3D array scheme is discussed for the high-density NCs scalable for photodetector application.
11
Salinaro, Alberto, Kassem Alassaad, Dethard Peters, Peter Friedrichs, and Gabriel Ferro. "MOS Interface Characteristics of In Situ Ge-Doped 4H-SiC Homoepitaxial Layers." Materials Science Forum 821-823 (June 2015): 512–15. http://dx.doi.org/10.4028/www.scientific.net/msf.821-823.512.
Full textAbstract:
We report on the electrical characterization of the Metal-Oxide-Semiconductor (MOS) interfacerealized on in-situ Ge-doped n-type 4H-SiC epilayers grown by Chemical Vapour Deposition(CVD). In order to study the relevance of this novel material for MOSFET technology, and in particularwhether the Ge presence deteriorates the SiC/SiO2 interface, we investigated the electrical propertiesof MOS capacitors realized on this novel substrate. Capacitance-Voltage measurements, performedto determine the quality of the SiC/SiO2 interface, show that the interface traps concentration is notincreased by the Ge content. The current through the oxide layer, monitored to study the bulk oxidequality and the tunneling mechanisms, indicates that Fowler-Nordheim conduction occurs and that thesubstrate-to-oxide barrier for electrons is comparable to the reported values for the SiC/SiO2 system.
12
Martínez, Haydee P., José A. Luna, Roberto Morales, et al. "Blue Electroluminescence in SRO-HFCVD Films." Nanomaterials 11, no. 4 (2021): 943. http://dx.doi.org/10.3390/nano11040943.
Full textAbstract:
In this work, electroluminescence in Metal-Insulator-Semiconductors (MIS) and Metal-Insulator-Metal (MIM)-type structures was studied. These structures were fabricated with single- and double-layer silicon-rich-oxide (SRO) films by means of Hot Filament Chemical Vapor Deposition (HFCVD), gold and indium tin oxide (ITO) were used on silicon and quartz substrates as a back and front contact, respectively. The thickness, refractive indices, and excess silicon of the SRO films were analyzed. The behavior of the MIS and MIM-type structures and the effects of the pristine current-voltage (I-V) curves with high and low conduction states are presented. The structures exhibit different conduction mechanisms as the Ohmic, Poole–Frenkel, Fowler–Nordheim, and Hopping that contribute to carrier transport in the SRO films. These conduction mechanisms are related to the electroluminescence spectra obtained from the MIS and MIM-like structures with SRO films. The electroluminescence present in these structures has shown bright dots in the low current of 36 uA with a voltage of −20 V to −50 V. However, when applied voltages greater than −67 V with 270 uA, a full area with uniform blue light emission is shown.
13
Weng, Ming Hung, A. E. Murphy, Craig Ryan, et al. "Influence of Phosphorous Auto-Doping on the Characteristics of SiO2/SiC Gate Dielectrics." Materials Science Forum 821-823 (June 2015): 492–95. http://dx.doi.org/10.4028/www.scientific.net/msf.821-823.492.
Full textAbstract:
We present the influence of phosphorous auto-doping on the characteristics of the oxide interface in 4H-SiC following high temperature gate oxide annealing. IV characteristics show no evidence of direct tunnelling breakdown; however Fowler Nordheim (F-N) conduction is observed in high electric field with the oxides able to sustain >10MV/cm. Capacitance Voltage data show DIT <1x1012 eV-1cm-2 close to the conduction band edge after POA, with undoped samples demonstrating DIT below 5x1011 eV-1cm-2. Photo CV data indicates smaller flat band voltage shifts of 0.6V at midpoint for the undoped samples, in comparison to 0.9V for the phosphorous doped devices. Temperature and bias stress tests at 200°C showed marginal hysteresis (0.3V) in both wafers. Reliability of time-dependent constant current and constant voltage characteristics revealed higher TDDB lifetimes in the undoped wafer. We conclude that the unintentional incorporation of phosphorous into the gate stack as a result of high temperature POA of the doped field oxide leads to a variation in flat band shift, higher DIT, and lower dielectric reliability.
14
Haasmann, Daniel, Sima Dimitrijev, Ji Sheng Han, and Alan Iacopi. "Growth of Gate Oxides on 4H-SiC by NO at Low Partial Pressures." Materials Science Forum 778-780 (February 2014): 627–30. http://dx.doi.org/10.4028/www.scientific.net/msf.778-780.627.
Full textAbstract:
In an attempt to significantly reduce the amount of nitric oxide (NO), commonly used to improve the quality of gate oxides on 4H–SiC, a series of alternative gate oxidation processes using a combination of O2and NO gas mixtures at low partial pressures were investigated. The properties of 4H–SiC/SiO2interfaces on n-type MOS capacitors were examined by the measurement of accumulation conductances over a range of frequencies. Oxide integrity was evaluated by current–voltage measurements and by the extraction of the conduction band offset barrier heights through Fowler–Nordheim (F–N) analysis. A notable reduction of accumulation conductance, indicating a reduction of near-interface traps (NITs), was observed over all measured frequencies for oxidation processes containing NO with a partial-pressure of only 2%. Gate oxides grown in mixture of O2and NO at low-partial-pressures demonstrated a considerable improvement of dielectric properties, increasing the barrier height to near theoretical values.
15
Guan, He, and Shaoxi Wang. "Leakage Current Conduction Mechanism of Au-Pt-Ti/ HfO2-Al2O3/n-InAlAs Metal-Oxide-Semiconductor Capacitor under Reverse-Biased Condition." Coatings 9, no. 11 (2019): 720. http://dx.doi.org/10.3390/coatings9110720.
Full textAbstract:
Au-Pt-Ti/high-k/n-InAlAs metal-oxide-semiconductor (MOS) capacitors with HfO2-Al2O3 laminated dielectric were fabricated. We found that a Schottky emission leakage mechanism dominates the low bias conditions and Fowler–Nordheim tunneling became the main leakage mechanism at high fields with reverse biased condition. The sample with HfO2 (4 m)/Al2O3 (8 nm) laminated dielectric shows a high barrier height ϕB of 1.66 eV at 30 °C which was extracted from the Schottky emission mechanism, and this can be explained by fewer In–O and As–O states on the interface, as detected by the X-ray photoelectron spectroscopy test. These effects result in HfO2 (4 m)/Al2O3 (8 nm)/n-InAlAs MOS-capacitors presenting a low leakage current density of below 1.8 × 10−7 A/cm2 from −3 to 0 V at 30 °C. It is demonstrated that the HfO2/Al2O3 laminated dielectric with a thicker Al2O3 film of 8 nm is an optimized design to be the high-k dielectric used in Au-Pt-Ti/HfO2-Al2O3/InAlAs MOS capacitor applications.
16
Hadjadj, A., G. Salace, and C. Petit. "Fowler–Nordheim conduction in polysilicon (n+)-oxide–silicon (p) structures: Limit of the classical treatment in the barrier height determination." Journal of Applied Physics 89, no. 12 (2001): 7994–8001. http://dx.doi.org/10.1063/1.1374479.
Full text
17
Ryu, Hojeong, and Sungjun Kim. "Gradually Tunable Conductance in TiO2/Al2O3 Bilayer Resistors for Synaptic Device." Metals 11, no. 3 (2021): 440. http://dx.doi.org/10.3390/met11030440.
Full textAbstract:
In this work, resistive switching and synaptic behaviors of a TiO2/Al2O3 bilayer device were studied. The deposition of Pt/Ti/TiO2/Al2O3/TiN stack was confirmed by transmission electron microscopy (TEM) and energy X-ray dispersive spectroscopy (EDS). The initial state before the forming process followed Fowler-Nordheim (FN) tunneling. A strong electric field was applied to Al2O3 with a large energy bandgap for FN tunneling, which was confirmed by the I-V fitting process. Bipolar resistive switching was conducted by the set process in a positive bias and the reset process in a negative bias. High-resistance state (HRS) followed the trap-assisted tunneling (TAT) model while low-resistance state (LRS) followed the Ohmic conduction model. Set and reset operations were verified by pulse. Moreover, potentiation and depression in the biological synapse were verified by repetitive set pulses and reset pulses. Finally, the device showed good pattern recognition accuracy (~88.8%) for a Modified National Institute of Standards and Technology (MNIST) handwritten digit database in a single layer neural network including the conductance update of the device.
18
Giubileo, Filippo, Francesca Urban, Alessandro Grillo, Aniello Pelella, Enver Faella, and Antonio Di Bartolomeo. "Direct Contacting of 2D Nanosheets by Metallic Nanoprobes." Materials Proceedings 4, no. 1 (2020): 16. http://dx.doi.org/10.3390/iocn2020-07931.
Full textAbstract:
We present a simple and fast methodology to realize metal contacts on two-dimensional nanosheets. In particular, we perform a complete characterization of the transport properties of MoS2 monolayer flakes on SiO2/Si substrates by using nano-manipulated metallic tips as metallic electrodes directly approached on the flake surface. We report detailed experimental investigation of transport properties and contact resistance in back-gated field effect transistor in which the Si substrate is used as the gate electrode. Moreover, profiting of the n-type conduction, as well as the high aspect ratio at the edge of the MoS2 flakes, we also explored the possibility of exploiting the material as a field emitter. Indeed, by retracting one of the metallic probes (the anode) from the sample surface, it has been possible to switch on a field-emitted current by applying a relatively low external electric field of few-tens of Volts for a cathode-anode separation distance below 1 µm. Experimental data are then analyzed in the framework of Fowler-Nordheim theory and its extension to the two-dimensional limit.
19
Chiguvare, Zivayi, and Jürgen Parisi. "Current Conduction in Poly(3-Hexylthiophene) and in Poly(3- Hexylthiophene) doped [6,6]-Phenyl C61-Butyric Acid Methylester Composite Thin Film Devices." Zeitschrift für Naturforschung A 67, no. 10-11 (2012): 589–600. http://dx.doi.org/10.5560/zna.2012-0062.
Full textAbstract:
Transport properties of poly(3-hexylthiophene) (P3HT), and of its blend with [6,6]-phenyl C61- butyric acid methylester (PCBM), were studied by analysing temperature dependent current-voltage characteristics of spin cast thin films sandwiched between aluminium electrodes in a metal-insulator- metal (MIM) configuration. It was found that in Al/P3HT/Al devices, the current is limited by space charge that accumulates near the hole injecting electrode due to the poor bulk transport properties of P3HT. At low temperatures and high applied electric fields the current density obeys a power law of the form J _ Vm, characteristic of space charge limited current (SCLC) in the presence of exponentially distributed traps within the band gap. These traps are filled by charge that is injected by quantum mechanical tunnelling, which is adequately described by the Fowler-Nordheim (FN) theory. By calculating the majority charge carrier mobility in Al/P3HT/Al and Al/P3HT:PCBM/Al devices from the Ohmic, SCLC, and FN tunnelling fits at different temperatures, we have obtained that the charge carrier mobility in P3HT is two orders smaller than the electron mobility in the P3HT:PCBM blend at room temperature, but comparable at low temperatures. This information is important in determining the origin of open circuit voltage and short circuit current limit in solar cells that employ this blend as the active layer.
20
Lean, Meng H., and Wei-Ping L. Chu. "Model for Charge Transport in Ferroelectric Nanocomposite Film." Journal of Polymers 2015 (March 23, 2015): 1–17. http://dx.doi.org/10.1155/2015/745056.
Full textAbstract:
This paper describes 3D particle-in-cell simulation of charge injection and transport through nanocomposite film comprised of ferroelectric ceramic nanofillers in an amorphous polymer matrix and/or semicrystalline ferroelectric polymer with varying degrees of crystallinity. The classical electrical double layer model for a monopolar core is extended to represent the nanofiller/nanocrystallite by replacing it with a dipolar core. Charge injection at the electrodes assumes metal-polymer Schottky emission at low to moderate fields and Fowler-Nordheim tunneling at high fields. Injected particles propagate via field-dependent Poole-Frenkel mobility. The simulation algorithm uses a boundary integral equation method for solution of the Poisson equation coupled with a second-order predictor-corrector scheme for robust time integration of the equations of motion. The stability criterion of the explicit algorithm conforms to the Courant-Friedrichs-Levy limit assuring robust and rapid convergence. Simulation results for BaTiO3 nanofiller in amorphous polymer matrix and semicrystalline PVDF with varying degrees of crystallinity indicate that charge transport behavior depends on nanoparticle polarization with antiparallel orientation showing the highest conduction and therefore the lowest level of charge trapping in the interaction zone. Charge attachment to nanofillers and nanocrystallites increases with vol% loading or degree of crystallinity and saturates at 30–40 vol% for the set of simulation parameters.
21
Kumar Chanana, Ravi. "Determination of hole effective mass in SiO2 and SiC conduction band offset using Fowler–Nordheim tunneling characteristics across metal-oxide-semiconductor structures after applying oxide field corrections." Journal of Applied Physics 109, no. 10 (2011): 104508. http://dx.doi.org/10.1063/1.3587185.
Full text
22
E., Papanasam, and Binsu J. Kailath. "Effect of post deposition annealing and post metallization annealing on electrical and structural characteristics of Pd/Al2O3/6H-SiC MIS capacitors." Microelectronics International 35, no. 2 (2018): 65–73. http://dx.doi.org/10.1108/mi-10-2016-0070.
Full textAbstract:
Purpose Al2O3 used as gate dielectric enables exploitation of higher electric field capacity of SiC, improving capacitive coupling and memory retention in flash memories. Passivation of traps at interface and in bulk which causes serious threat is necessary for better performance. The purpose of this paper is to investigate the effect of post-deposition rapid thermal annealing (PDA) and post-metallization annealing (PMA) on the structural and electrical characteristics of Pd/Al2O3/6H-SiC capacitors. Design/methodology/approach Al2O3 film is deposited by ALD; PDA is performed by rapid thermal annealing (RTA) in N2 at 900°C for 1 min and PMA in forming gas for 10 and 40 min. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) measurements data are studied in addition to capacitance-voltage (C-V) and current-voltage (I-V) characteristics for the fabricated Pd/Al2O3/SiC capacitors. Conduction mechanism contributing to the gate leakage current is extracted for the entire range of gate electric field. Findings RTA forms aluminum silicide at the interface causing an increase in the density of the interface states and gate leakage current for devices with an annealed film, when compared with an as-deposited film. One order improvement in leakage current has been observed for the devices with RTA, after subjecting to PMA for 40 min, compared with those devices for which PMA was carried out for 10 min. Whereas, no improvement in leakage current has been observed for the devices on as-deposited film, even after subjecting to PMA for 40 min. Conduction mechanisms contributing to gate leakage current are extracted for the investigated Al2O3/SiC capacitors and are found to be trapfilled limit process at low-field regions; trapassisted tunneling in the mid-field regions and Fowler–Nordheim (FN) tunneling are dominating in high-field regions. Originality/value The effect of PDA and PMA on the structural and electrical characteristics of Pd/Al2O3/SiC capacitors suitable for flash memory applications is investigated in this paper.
23
Kyritsakis, A., and J. P. Xanthakis. "Derivation of a generalized Fowler–Nordheim equation for nanoscopic field-emitters." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 471, no. 2174 (2015): 20140811. http://dx.doi.org/10.1098/rspa.2014.0811.
Full textAbstract:
In this paper, we derive analytically from first principles a generalized Fowler–Nordheim (FN) type equation that takes into account the curvature of a nanoscopic emitter and is generally applicable to any emitter shape provided that the emitter is a good conductor and no field-dependent changes in emitter geometry occur. The traditional FN equation is shown to be a limiting case of our equation in the limit of emitters of large radii of curvature R. Experimental confirmation of the validity of our equation is given by the data of three different groups. Upon applying our equation to experimental FN plots complying with the above limitations, one may deduce (i) R and (ii) standard field emission parameters—e.g. enhancement factor—with better accuracy than by using the FN equation.
24
Zhang, Yidong. "Observation of the enhanced tunnel current of NiO thin films in grain boundary by peakforce TUNA." Microelectronics International 36, no. 4 (2019): 160–64. http://dx.doi.org/10.1108/mi-02-2019-0008.
Full textAbstract:
Purpose The purpose of this paper is to investigate the nanoscale electric performance of NiO thin films in grain boundary and grain face. Design/methodology/approach PeakForce tunnel atomic force is applied to visualize the nanoscale current imaging of the NiO thin film on fluorine tin oxide substrate. Findings The results show that the grain boundary has a significant impact on the nanoscale current of the NiO film. The electronic conductivity and in grain boundary is higher than that of the NiO film in grain face. The width of the conductive zone in the NiO film over grain boundaries is ∼ 60 nm. The tunnel current between the tip and the NiO film is consistent with the Fowler–Nordheim tunnel model. Originality/value The higher tunnel current in grain boundary is probably attributed to the enhanced energy band bending and adhesion force.
25
Forbes, Richard G. "Screened field enhancement factor for a tall closely spaced array of identical conducting posts and implications for Fowler-Nordheim-type equations." Journal of Applied Physics 111, no. 9 (2012): 096102. http://dx.doi.org/10.1063/1.4711091.
Full text
26
Qin, Xi-Zhou, Wie-Liang Wang, Ning-Sheng Xu, Zhi-Bing Li, and Richard G. Forbes. "Analytical treatment of cold field electron emission from a nanowall emitter, including quantum confinement effects." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 467, no. 2128 (2010): 1029–51. http://dx.doi.org/10.1098/rspa.2010.0460.
Full textAbstract:
An elementary approximate analytical treatment of cold field electron emission (CFE) from a classical nanowall (i.e. a blade-like conducting structure on a flat surface) is presented. This paper first discusses basic CFE theory for situations where quantum confinement occurs transverse to the emitting direction. It develops an abstract CFE equation more general than Fowler–Nordheim type (FN-type) equations, and then applies this to classical nanowalls. With sharp emitters, the field in the tunnelling barrier may diminish rapidly with distance; an expression for the on-axis transmission coefficient for nanowalls is derived by conformal transformation. These two effects interact to generate complex emission physics, and lead to regime-dependent equations different from FN-type equations. Thus: (i) the zero-field barrier height H R for the highest occupied state at 0 K is not equal to the local thermodynamic work-function ϕ , and H R rather than ϕ appears in equations; (ii) in the exponent, the power dependence on macroscopic field F M can be F −2 M rather than F −1 M ; (iii) in the pre-exponential, explicit power dependences on F M and H R differ from FN-type equations. Departures of this general kind are expected when nanoscale quantum confinement occurs. FN-type equations are the equations that apply when no quantum confinement occurs.
27
H. Lean, Meng, and Wei-Ping L. Chu. "Simulation of charge packet formation in layered polymer film." COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 33, no. 4 (2014): 1396–415. http://dx.doi.org/10.1108/compel-09-2013-0291.
Full textAbstract:
Purpose – The purpose of this paper is to describe a rapid and robust axisymmetric hybrid algorithm to create dynamic temporal and spatial charge distributions, or charge map, in the simulation of bipolar charge injection using Schottky emission and Fowler-Nordheim tunneling, field-dependent transport, recombination, and bulk and interfacial trapping/de-trapping for layered polymer films spanning the range from initial injection to near breakdown. Design/methodology/approach – This hybrid algorithm uses a source distribution technique based on an axisymmetric boundary integral equation method (BIEM) to solve the Poisson equation and a fourth-order Runge-Kutta (RK4) method with an upwind scheme for time integration. Iterative stability is assured by satisfying the Courant-Friedrichs-Levy (CFL) stability criterion. Dynamic charge mapping is achieved by allowing conducting and insulating boundaries and material interfaces to be intuitively represented by equivalent free and bound charge distributions that collectively satisfy all local and far-field conditions. Findings – Charge packets cause substantial increase of electric stress and could accelerate the breakdown of polymeric capacitors. Conditions for the creation of charge packets are identified and numerically demonstrated for a combination of impulsive step excitation, high charge injection, and discontinuous interface. Originality/value – Metallized bi-axially oriented polypropylene (BOPP) dielectric thin film capacitor with self-clearing and enhanced current carrying capability offer an inexpensive and lightweight alternative for efficient power conditioning, energy storage, energy conversion, and pulsed power. The originality is the comprehensive physics and multi-dimensional modeling which span the dynamic range from initial injection to near breakdown. This model has been validated against some empirical data and may be used to identify failure mechanisms such as charge packets, gaseous voids, and electroluminescence. The value lies in the use of this model to develop mitigation strategies, including re-designs and materials matching, to avoid these failure mechanisms.
28
Aarik, J., V. Bichevin, I. Jõgi, H. Käämbre, M. Laan, and V. Sammelselg. "Fowler-nordheim tunnelling in Au−TiO2−Ag film structures." Open Physics 2, no. 1 (2004). http://dx.doi.org/10.2478/bf02476278.
Full textAbstract:
AbstractI-V-characteristics have been measured for Au−TiO2−Ag structures with TiO2 layers of 30 and 180 nm thickness. The TiO2 films were grown by atomic layer deposition (ALD) technique. In the case of negative bias on the Au electrode, the conduction currents through TiO2 layers follow the Fowler-Nordheim formula for field emission over several orders of magnitude. The bulk of the currents may be attributed to tunnelling, seemingly through a Schottky barrier at the Au−TiO2 junction. In the case of reversed polarity the currents are also observed, but cannot be interpreted as tunnelling.
29
Liu, Li, and Yin-Tang Yang. "Current conduction mechanisms in thermal nitride and dry gate oxide grown on 4H-silicon carbide (SiC)." Journal of Advanced Oxidation Technologies 20, no. 1 (2017). http://dx.doi.org/10.1515/jaots-2016-0177.
Full textAbstract:
AbstractCurrent conduction mechanisms of SiC metal-oxide-semiconductor (MOS) capacitors on n-type 4H-SiC with or without NO annealing have been investigated in this work. It has been revealed that Fowler-Nordheim (FN) tunneling is the dominating current conduction mechanism in high electrical fields, with barrier height of 2.67 and 2.54 eV respectively for samples with NO and without NO annealing. A higher barrier height for NO-annealed sample indicates the effect of N element on the SiC/SiO
30
Okhonin, S., A. Ils, D. Bouvet, et al. "Two-Band Tunneling Currents and Stress-Induced Leakage in Ultra-Thin SiO2 Films." MRS Proceedings 567 (1999). http://dx.doi.org/10.1557/proc-567-253.
Full textAbstract:
ABSTRACTThe conduction band and valence band electron tunneling currents in ultra-thin SiO2 films at the transition from direct to Fowler-Nordheim tunneling regimes are studied. The slopes of the current voltage characteristics agree well with the simulations performed. The Stress-Induced Leakage Current (SILC) behavior is quite similar for both conduction and valence band currents even if the amplitude of the valence band SILC is much lower. We show that a linear dependence exists between the stress-induced interface trap density and both valence and conduction band SILC. A new model of SILC is also proposed.
31
Yi, Kyoung-Soo, Deok-Ho Cho, Jeong Yong Lee, Kee-Soo Nam, Sang-Won Kang, and Jin-Hyo Lee. "The Electrical Properties of Polyoxide Depending on the Polycrystalline-Si Formation Conditions." MRS Proceedings 182 (1990). http://dx.doi.org/10.1557/proc-182-315.
Full textAbstract:
AbstractPrior to growth of polyoxide, amorphous-Si with a cap of low temperature oxide was annealed to improve the dielectric property of polyoxide. Current-electric field, critical electric field, critical electric field histogram, and Fowler-Nordheim conduction plot were evaluated. The interface of polyoxide and poly-Si was observed with a transmission electron microscope. The annealing of the amorphous-Si prior to oxidation was effective to improve the dielectric property of the polyoxide.
32
Kanwal, Alokik, and Manish Chhowalla. "Nanoscale Measurements in Organic Memory Devices from C60 in Insulating Polymers." MRS Proceedings 905 (2005). http://dx.doi.org/10.1557/proc-0905-dd06-03.
Full textAbstract:
AbstractFollowing our pervious works demonstrating all-organic memory devices based on a nanocomposite material consisting of C60 molecules dispersed in an insulating polymer. In this paper, we will report on conducting atomic force microscopy (c-AFM) measurements from nanosized regions on memory devices. The c-AFM nanoscale measurements show a hysteresis of high and low conductance states, in agreement with our previous reports on macroscopic memory devices. The c-AFM measurements were verified by 30nm gap cell devices fabricated via e-beam lithography, which also showed similar current values. Analysis of our data reveals that the conduction mechanism switches from direct tunneling to Fowler-Nordheim tunneling above a threshold voltage.
33
Lay, T. S., M. Hong, J. Kwo, J. P. Mannaerts, W. H. Hung, and D. J. Huang. "Energy Band Offsets at a Ga2O3(Gd2O3)-GaAs Interface." MRS Proceedings 573 (1999). http://dx.doi.org/10.1557/proc-573-131.
Full textAbstract:
ABSTRACTWe report the energy band offsets at a Ga2O3(Gd2O3)-GaAs interface. The valence-band offset (ΔEv) is ∼ 2.6 eV, measured by soft x-ray photoemission spectroscopy. Analysis of the current-voltage characteristics of a Pt-Ga2O3(Gd2O3)-GaAs MOS (metal-oxide-semiconductor) structure, which are dominated by Fowler-Nordheim tunneling, reveals a conduction-band offset (ΔEC) ∼ 1.4 eV at the Ga2O3(Gd2O3)-GaAs interface and an electron effective mass (m*) ∼ 0.29 me of the Ga2O3(Gd2O3) film.
34
Ahn, Kun Ho, Sang Sub Kim, and Sunggi Baik. "Thickness Dependence of Leakage Current Behavior in Epitaxial (Ba,Sr)TiO3 Thin Films." MRS Proceedings 688 (2001). http://dx.doi.org/10.1557/proc-688-c13.7.1.
Full textAbstract:
AbstractThickness dependence of leakage current behaviors was investigated in epitaxial (Ba0.5Sr0.5)TiO3 thin films with different thicknesses of 55 - 225 nm prepared on Pt(001)/MgO(001) substrates by a radio-frequency magnetron sputtering technique. Below a certain critical film thickness (≤ 55 nm), the Schottky emission is a ruling leakage conduction mechanism over a wide electric field range. In contrast, in thicker films (> 55 nm), the Schottky emission still operates at low electric fields, however at high electric fields the Fowler-Nordheim (F-N) tunneling dominates. The transition film thickness appears to be associated with overlapping of the depletion layers formed at the top and bottom electrode interfaces.
35
Fujikawa, Hisayoshi, and Yasunori Taga. "Effects of Additive Elements on Electrical Properties of Tantalum Oxide Films." MRS Proceedings 378 (1995). http://dx.doi.org/10.1557/proc-378-1025.
Full textAbstract:
AbstractTa2O5-based composite films prepared by magnetron sputtering have been investigated with respect to their dielectric properties. As additive third oxides, Y2O3 and WO3 were found to be effective in improving insulating properties without decreasing their dielectric constant. Furthermore, electrical properties of Ta2O5-Y2O3 films were investigated by measuring the current-voltage characteristics in the temperature range from 100 to 330 K. Measurement of temperature dependence of the leakage current revealed that the conduction mechanism at RT changed from the Poole-Frenkel type to the Fowler-Nordheim tunneling type by adding Y2O3 into Ta2O5. Based on the detailed analysis of the results, it is concluded that the addition of Y2O3 into the Ta2O5 film is effective in the reduction of defect density without high-temperature annealing and the alteration of electrical conduction mechanisms of the films.
36
Lim, Way F., and Kuan Y. Cheong. "Effects of Post-Deposition Annealing Temperature on Band Alignment and Electrical Characteristics of Lanthanum Cerium Oxide on 4H-SiC." MRS Proceedings 1433 (2012). http://dx.doi.org/10.1557/opl.2012.1144.
Full textAbstract:
ABSTRACTInvestigation of lanthanum cerium oxide as a gate oxide on 4H-SiC was performed by varying post-deposition annealing temperature from 400 to 1000°C. Energy band alignment and band gap of bulk oxide and interfacial layer (IL) with respect to SiC were extracted using X-ray photoelectron microscopy. Two band alignment structures were proposed and the change of band alignment was affected by the changes in chemical composition in bulk oxide and in IL that may induce lattice strains and dipoles. A conduction band offset of IL/SiC was 0.97 eV for sample annealed at 1000°C, which was comparable to the value extracted from Fowler-Nordheim model. The acquisition of sufficient conduction band offset, coupled with the lowest slow trap density, effective oxide charges, interface trap density, as well as total interface trap density, yielded the lowest leakage current density for this sample.
37
Mereu, Bogdan, George Sarau, and Marin Alexe. "Conduction Mechanisms in SrTiO3 Thin Films on Silicon." MRS Proceedings 745 (2002). http://dx.doi.org/10.1557/proc-745-n9.5/t7.5.
Full textAbstract:
ABSTRACTNew materials with high dielectric constant are currently being explored to replace silicon dioxide as gate dielectric for device scaling below 0.1 μm. With respect to conventional SiO2, these high permittivity dielectrics provide the required equivalent oxide thickness (EOT) without of further reduction of the insulator physical thickness, which is a key issue to limit gate leakage current and to maintain comparable MOSFET operation and reliability. The present paper presents preliminary results on conduction mechanisms in thin epitaxial SrTiO3 films grown by MBE on Si (100). I-V measurements were performed on Al/STO/Si structures at temperatures ranging from 40 K to 290 K. At temperatures lower than 100 K the conduction mechanism of electrons from gate electrode across the oxide barrier neither Schottky emission nor tunneling. For temperatures higher than 100 K Schottky emission occurs and barrier heights were extracted, showing an approximate linearly increase with temperature. In case of Si/STO interface, a Fowler-Nordheim tunneling mechanism was detected at 40 K and at intermediate fields. The extracted barrier heights are: 0.07 eV at Si/STO interface and from 0.26 eV (130 K) to 0.53 eV (290 K) at Al/STO interface.
38
Mereu, Bogdan, George Sarau, and Marin Alexe. "Conduction Mechanisms in SrTiO3 Thin Films on Silicon." MRS Proceedings 747 (2002). http://dx.doi.org/10.1557/proc-747-t7.5/n9.5.
Full textAbstract:
ABSTRACTNew materials with high dielectric constant are currently being explored to replace silicon dioxide as gate dielectric for device scaling below 0.1 μm. With respect to conventional SiO2, these high permittivity dielectrics provide the required equivalent oxide thickness (EOT) without of further reduction of the insulator physical thickness, which is a key issue to limit gate leakage current and to maintain comparable MOSFET operation and reliability. The present paper presents preliminary results on conduction mechanisms in thin epitaxial SrTiO3 films grown by MBE on Si (100). I-V measurements were performed on Al/STO/Si structures at temperatures ranging from 40 K to 290 K. At temperatures lower than 100 K the conduction mechanism of electrons from gate electrode across the oxide barrier neither Schottky emission nor tunneling. For temperatures higher than 100 K Schottky emission occurs and barrier heights were extracted, showing an approximate linearly increase with temperature. In case of Si/STO interface, a Fowler-Nordheim tunneling mechanism was detected at 40 K and at intermediate fields. The extracted barrier heights are: 0.07 eV at Si/STO interface and from 0.26 eV (130 K) to 0.53 eV (290 K) at Al/STO interface.
39
Lerner, Peter, P. H. Cutler, and N. M. Miskovsky. "Wide Bandgap Semiconductors for Cold Cathodes: A Theoretical Analysis." MRS Proceedings 449 (1996). http://dx.doi.org/10.1557/proc-449-1109.
Full textAbstract:
ABSTRACTIn this paper we describe the field emission from wide band-gap semiconductor thin film electron sources as a three-step process. Internal field emission is the mechanism for electron injection at the metal-semiconductor cathode interface. Under an internal field, electrons injected into the conduction band can propagate quasi-ballistically through the thin semiconductor film. At the vacuum interface, they are field emitted across a PEA or NEA surface. Consistent with the electron injection mechanism we have done molecular dynamics simulations for GaN films with an initial energy distribution corresponding to a Fowler-Nordheim (FN) spectrum. Results demonstrate quasi-ballistic propagation and approximate preservation of the FN energy distribution. Furthermore, high levels of n-doping in GaN (∼ 1017cm−3) do not inhibit transport in thin films (<0.1 μm).
40
Ravindra, N. M., O. L. Russo, D. Fathy, J. Narayan, A. R. Heyd, and K. Vedam. "Electrical, Optical and Structural Properties of Thin SiO2 Films On Si." MRS Proceedings 105 (1987). http://dx.doi.org/10.1557/proc-105-169.
Full textAbstract:
AbstractBreakdown voltage, static current-voltage, spectroscopic ellipsometry (SE), electrolyte electroreflectance (EER) and high resolution transmission electron microscopic (HRTEM) studies of thermally grown thin films of SiO2 on silicon (800°C - dry) are reported here. The investigation of the electrical properties of these films lead us to suggest the criteria for determining the breakdown voltage of these 20nm thick SiO2 films. The Fowler-Nordheim tunneling contribution to current conduction mechanisms in SiO2 has been considered in evaluating these criteria. SE, EER & HRTEM studies have been performed on SiO2 films of thicknesses in the range of 1–20 nm. These studies lead us to determine the thickness of the non-stoichiometric silicon-rich oxide existing at the Si-SiO2 interface. EER studies show that the relative surface state densities for different film thicknesses can be determined. The role of the transition region in determining the dielectric strength of thin SiO2 films is discussed.
41
Dumin, D. J., J. R. Maddux, and D. P. Wong. "Stress Induced Increased Low Level Leakage in Thin Oxides." MRS Proceedings 284 (1992). http://dx.doi.org/10.1557/proc-284-319.
Full textAbstract:
ABSTRACTIt has been observed that the low-level, pre-tunneling currents through thin gate oxides increased after the oxides had been stressed at high voltages. The number of traps inside of the oxide generated by the stress has been shown to increase as the 1/3 power of the fluence that had passed through the oxide during the stress. The increases in the low-level, pre-tunneling currents have been shown to be proportional to the number of stress generated traps in the oxide and not to the fluence during the stress. The voltage dependences of the excess low-level leakage currents were stress and measurement polarity dependent. Attempts have been made to fit the voltage dependences of the excess low-level currents to Fowler-Nordheim tunneling, Frenkel-Poole conduction or Schottky barrier lowering. The increase in the portion of the low-level, pre-tunneling current that was not dependent on stress/measurement polarity sequence was best fit using Schottky emission currents. The model that has been developed to describe the increases in the low-level currents has centered on trap-assisted currents through the oxides.
42
Rahimi, Ronak, and D. Korakakis. "Charge transport in ambipolar pentacene thin film transistors." MRS Proceedings 1286 (2011). http://dx.doi.org/10.1557/opl.2011.239.
Full textAbstract:
ABSTRACTAmbipolar organic transistors are technologically interesting because of their potential applications in light-emitting field-effect transistors [1] and complementary-metal-oxide-semiconductor (CMOS) devices by providing ease of design, low cost of fabrication, and flexibility [2]. Although common organic semiconductors show either n- or p-type charge transport characteristic, organic transistors with ambipolar characteristics have been reported recently. In this work, we show that ambipolar transport can be achieved within a single transistor channel using LiF gate dielectric in the transistors with pentacene active layer. This ambipolar behavior can be controlled by the applied source-drain and gate biases. It was found that at low source-drain biases multistep hopping is the dominant conduction mechanism, while in high voltage regimes I-V data fits in Fowler-Nordheim (F-N) tunneling model. From the slope of the F-N plots, the dependency between field enhancement factor and the transition point in conduction mechanism upon gate bias has been extracted. The transition points show more dependency on gate voltage for negative biases compared to the positive biases. While sweeping negative gate voltages from -5 to -20 V, the source-drain voltages change from about 27 to 17 V. On the other hand, for positive gate voltages from 5 to 20 V, the value of the transition point stays at approximately 36 V. In order to further understand the transport mechanisms, new structures with an interface layer between dielectric and active layer have been fabricated and characterized. As expected, a significant decrease in the amount of the source-drain current has been observed after introducing the interface layer.
43
Ishikawa, Satoshi, Szu-Lin Cheng, Yiyang Gong, Jelena Vuckovic, and Yoshio Nishi. "Optimization of Light Emission from Silicon Nanocrystals Grown by PECVD." MRS Proceedings 1257 (2010). http://dx.doi.org/10.1557/proc-1257-o03-05.
Full textAbstract:
AbstractLight emission from Si nanocrystals ( SiNCs ) embedded in Si oxide was studied in this work. SiNCs were fabricated by annealing a Si-rich oxide ( SRO ) deposited by a plasma-enhanced chemical vapor deposition ( PECVD ) system. The gas flow ratio between SiH4 and N2O of a precursor gas was changed by varying a N2O gas flow rate and the annealing temperature was varied from 800 to 1100°C. The highest PL intensity was obtained with a N2O flow rate of 125sccm, a SiH4 flow rate of 1400sccm and annealing temperature of 900°C. The PL wavelength was also controlled by N2O gas flow rate and annealing temperature, with blue shifting to the visible wavelengths for increasing N2O flow rate and decreasing annealing temperature. In addition, forming gas ( 4% H2 ) anneal for 1 hour, which is a common method to passivate Si surface, at 500°C to SiNCs was used to further enhance the emission intensity. To approach emission at shorter wavelength, the Si oxide with SiNCs / SiO2 multi layer structure ( MLS ) was also fabricated by similar methods. The SiO2 layer was used as a diffusion barrier to extra Si on vertical direction during the annealing process. Such a barrier can effectively reduce the diameter of SiNCs and shift the emission peak to shorter wavelength. A blue shift from PL was clearly observed as the thickness of Si oxide layer with SiNCs in MLS reduces. Finally, the PIN light emitting diode which consisted of n-type poly-Si / Si oxide with SiNCs / p-type poly-Si structure was also fabricated to study the electroluminescence ( EL ) of SiNCs. The current under the forward bias was about 10 times higher than under the reverse bias. The carrier injection mechanism assumed that Poole-Frenkel type conduction or hopping conduction dominates under a low electric field and Fowler-Nordheim tunneling dominates under a high electric field. EL was obtained with a forward bias voltage of around 6V and EL emission efficiency was proportional to the current density.
44
Lichtenwalner, Daniel J., Lin Cheng, Scott Allen, John W. Palmour, Aivars Lelis, and Charles Scozzie. "Comparison of channel mobility and oxide properties of MOSFET devices on Si-face (0001) and A-face (11-20) 4H-SiC." MRS Proceedings 1693 (2014). http://dx.doi.org/10.1557/opl.2014.530.
Full textAbstract:
ABSTRACTIn this report we present results comparing lateral MOSFET properties of devices fabricated on Si-face (0001) and A-face (11-20) 4H-SiC, with nitric oxide passivation anneals. We observe a field-effect mobility of 33 cm2/V.s on p-type 5×1015 doped Si-face. These devices have a peak field-effect mobility which increases with temperature, indicative of a channel mobility limited by coulomb scattering. On 1×1016 p-type A-face SiC, the peak channel mobility is observed to be 80 cm2/V.s, with a negative temperature dependence, indicating that phonon-scattering effects dominate, with a much lower density of shallow acceptor traps. This > 2x higher channel mobility would result in a substantial decrease in on-resistance, hence lower power losses, for 4H-SiC power MOSFETs with voltage ratings below 2 kV. However, MOS C-V and gate leakage measurements indicate very different oxide and interface quality on each SiC face. For example, the Fowler-Nordheim (FN) conduction-band (CB) barrier height for electron tunneling at the SiO2/SiC interface is 2.8 eV on Si-face SiC, while it is 2.5 eV or less on A-face SiC. For the valence-band side, the effective FN barrier height at the valence-band (VB) side of only 1.6 eV on A-face SiC, while the VB barrier height is about 3.1 eV on Si-face SiC. Moreover, C-V of the MOS gate on A-face indicates the presence of a high-density of deep hole traps. It is apparent that oxides on alternative crystal faces, very promising in terms of channel mobility, require further study for complete understanding and control of the interface properties.
45
Carreras, Josep, B. Garrido, J. Arbiol, and J. R. Morante. "Low Voltage and High Speed Silicon Nanocrystal Memories." MRS Proceedings 830 (2004). http://dx.doi.org/10.1557/proc-830-d1.9.
Full textAbstract:
ABSTRACTWe have studied a set of MOS cell structures with 30 nm thick thermal oxide implanted with Si at high doses (10, 15 and 20 atomic % at projected range) in which Si nanocrystals (Si-nc) have been precipitated by annealing at 1100 °C. Energy filtered transmission electron microscopy reveals: i) a central layer of Si-nc with a mean size of 2.8 nm; ii) a control oxide of 12.5 nm completely free of Si-nc and iii) a tunnel oxide of about 2.5 nm. This narrow tunnel oxide enables the direct tunnel for charging and discharging which is a must for high speed and good reliability. However, this results in typical retention times ranging from only few hours to several months, depending on the concentration of Si-nc. For developing low voltage memories we have focused on the highest Si excess sample, which shows fast write times (tens of μs) at very low gate fields (±2 MV/cm or ±6V). The onset of Fowler-Nordheim conduction is of about ±6 MV/cm by J-V measurements (±18V), which means that the structure works in a direct tunnel regime. To increase the retention time we have performed an additional annealing step in diluted O2 for 16 and 32 minutes, resulting in a dramatic increase in the retention times, which is attributed to the re-growth of an additional tunnel oxide which eliminates surface roughness, remaining Si excess and defects at the Si-SiO2 interface. This additional oxidation step produces also a decrease in the mean size of the Si-nc distribution. Thus, we increase the retention time beyond the 10 years standard limit. Finally, the writing times can be traded-off by increasing slightly the program voltage up to ±2.7 MV/cm or ±8V.
46
Ostraat, Michele L., and Jan W. De Blauwe. "Future Silicon Nanocrystal Nonvolatile Memory Technology." MRS Proceedings 686 (2001). http://dx.doi.org/10.1557/proc-686-a5.2.
Full textAbstract:
AbstractA great deal of research interest is being invested in the fabrication and characterization of nanocrystal structures as charge storage memory devices. In these flash memory devices, it is possible to measure threshold voltage shifts due to charge storage of only a few electrons per nanocrystal at room temperature. Although a variety of methods exist to fabricate nanocrystals and to incorporate them into device layers, control over the critical nanocrystal dimensions, tunnel oxide thickness, and interparticle separation and isolation remains difficult to achieve. This control is vital to produce reliable and consistent devices over large wafer areas. To address these control issues, we have developed a novel two-stage ultra clean reactor in which the Si nanocrystals are generated as single crystal, nonagglomerated, spherical aerosol particles from silane decomposition at 950°C at concentrations exceeding 108 cm−3 at sizes below 10 nm. Using existing aerosol instrumentation, it is possible to control the particle size to approximately 10% on diameter. In the second reactor, particles are passivated with a high quality oxide layer with shell thickness controllable from 0.7 to 2.0 nm. The two-stage aerosol reactor is integrated to a 200 mm wafer deposition chamber such that controlled particle densities can be deposited thermophoretically. With nanocrystal deposits of 1013 cm−2, contamination of transition metals and other elements can be controlled to less than 1010 atoms cm−2.We have fabricated 0.2 μm channel length aerosol nanocrystal floating gate memory devices using conventional MOS ULSI processing on 200 mm wafers. The aerosol nanocrystal memory devices exhibit normal transistor characteristics with drive current 30 μA/μm, subthreshold slope 200 mV/dec, and drain induced barrier lowering 100 mV/V, typical values for thick gate dielectric high substrate doped nonvolatile memory devices. Uniform Fowler-Nordheim tunneling is used to program and erase these memory devices. Despite 5 nm tunnel oxides, threshold voltage shifts > 2 V have been achieved with microsecond program and millisecond erase times at moderate operating voltages. The aerosol devices also exhibit excellent endurance cyclability with no window closure observed after 105 cycles. Furthermore, reasonable disturb times and long nonvolatility are obtained, illustrating the inherent advantage of discrete nanocrystal charge storage. No drain disturb was detected even at drain biases of 4V, indicating that little or no charge conduction occurs in the nanocrystal layer. We have demonstrated promise for aerosol nanocrystal memory devices. However, numerous issues exist for the future of nanocrystal devices. These technology issues and challenges will be discussed as directions for future work.
47
Murrell, Martin P., Sean J. O'Shea, Jack Barnes, Mark E. Welland, and Carl J. Sofield. "Conducting AFM: Applications to Semiconductor Surfaces." MRS Proceedings 386 (1995). http://dx.doi.org/10.1557/proc-386-371.
Full textAbstract:
ABSTRACTThe use of Conducting Probe Atomic Force Microscopy to give nm scale electronic characterisation of surfaces is reviewed. Local conductance, Kelvin Probe work function measurements, Fowler-Nordheim tunnelling and local C-V characterisation techniques are outlined. The principle results of these and their applications to the semiconductor surface and thin film characterisation are discussed. We present tunnelling data from silicon through varying oxide thickness using conducting AFM and scanning Kelvin Probe measurements from sub micron MOS capacitors. The F-N tunnelling technique has also been used on epitaxial silicon surfaces with atomically flat topography.The inherent problems associated with quantitative, reproducible measurements are outlined, and the potential applications of the measurements to surface and thin film technology are discussed.
48
Forbes, Richard G. "Theory and Modelling of Field-Induced Electron Emission." MRS Proceedings 621 (2000). http://dx.doi.org/10.1557/proc-621-r3.1.1.
Full textAbstract:
ABSTRACTThis paper addresses issues in the theory of field-induced electron emission. First, it summarises our present understanding of the theory of Fowler-Nordheim (FN) plots, and shows the relationship between a recent precise (in standard FN theory) approach to the interpretation of the FN-plot intercept and older approximate approaches. Second, it comments on the interpretation of FN plots taken from semiconductor field emitters. Third, it summarises the main points of a recent hypothesis about the mechanism of field-induced emission from carbonbased films and other electrically nanostructured heterogeneous (ENH) materials. Weaknesses in previous hypotheses are noted. It is hypothesised that thin films of all ENH materials, when deposited on a conducting substrate, will emit electrons in appropriate circumstances. Such films emit electrons at low macroscopic fields because they contain conducting nanostructure inside them: this structure generates sufficient geometrical field enhancement near the film/vacuum interface that more-or-less normal Fowler-Nordheim emission can occur. In connection with experiments on amorphous carbon films carried out by a group in Fribourg, it is shown that nanostructure of the size measured by scanning probe techniques should be able to generate field enhancement of the size measured in field electron spectroscopy experiments. This result provides a quantitative corroboration of other work suggesting that emission from amorphous carbon films is primarily due to geometrical field enhancement by nanostructures inside the film. Some counter-arguments to the internal-field-enhancement hypothesis are considered and disposed of. Some advantages of ENH materials as broad-area field emission electron sources are noted; these include control of material design.
49
Kabulski, Adam, John Harman, Parviz Famouri, and Dimitris Korakakis. "Development of Aluminum Nitride/Platinum Stack Structures for an Enhanced Piezoelectric Response." MRS Proceedings 955 (2006). http://dx.doi.org/10.1557/proc-0955-i15-35.
Full textAbstract:
ABSTRACTAluminum nitride (AlN) films are being investigated for piezoelectric and high temperature applications, but the piezoelectric response is still much lower than that of more common piezoelectric materials such as lead zirconate titanate or zinc oxide. A method of maximizing the piezoelectric response of aluminum nitride has been explored by depositing stack structures composed of aluminum nitride and platinum. These stack structures were created by depositing a thin, ∼50nm, metal layer in between thicker, ∼150-350nm, layers of the piezoelectric film. Platinum was chosen as the metal interlayer due to the tendency of AlN to become highly c-oriented when deposited on Pt. An electric field was applied across the structure and displacements were measured using a Laser Doppler Vibrometer. A maximum piezoelectric coefficient d33 was found to be over two times larger than the theoretical value for AlN (3.9pm/V). However, some of the stack structures were found to be conductive when measuring the displacement. I-V measurements as well as Fowler-Nordheim theory and plots were applied to investigate tunneling due to high electric fields in the structures.
50
de Assis, T. A. "The role of Hurst exponent on cold field electron emission from conducting materials: from electric field distribution to Fowler-Nordheim plots." Scientific Reports 5, no. 1 (2015). http://dx.doi.org/10.1038/srep10175.
Full text