Journal articles: 'High-electron mobility (HEMT) devices'

1

Green, F. "Charge Fluctuations in High-Electron-Mobility Transistors: A Review." Australian Journal of Physics 46, no. 3 (1993): 447. http://dx.doi.org/10.1071/ph930477.

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The physics of high-electron-mobility transistors (HEMTs) plays a central role in contemporary design for millimetre-wave communications. HEMTs are the early fruits in a harvest of increasingly radical devices whose structural features are measured in nanometres. The operating principles of these devices are richly varied, and almost always far from classical. One of the tasks for device physics is to understand fluctuation phenomena, .or noise: the control of charge fluctuations is basic to high performance, yet the description of these processes remains incomplete if not obscure. This paper reviews some aspects of charge-transport noise that affect HEMT operation.

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Wang, Chih Hao, Liang Yu Su, Finella Lee, and Jian Jang Huang. "Applications of GaN-Based High Electron Mobility Transistors in Large-Size Devices." Applied Mechanics and Materials 764-765 (May 2015): 486–90. http://dx.doi.org/10.4028/www.scientific.net/amm.764-765.486.

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We demonstrate a novel design of large-size device in AlGaN/GaN high-electron-mobility transistor (HEMT). Depletion mode (D-mode) HEMTs and enhancement mode (E-mode) HEMTs are fabricated in our research. The saturation current of D-mode HEMTs is over 6A. By using Cascode structure, the D-mode HEMT becomes a normally-off device efficiently, and the threshold voltage of it rises from-7V to 2V. By using BCB (Benzocyclobutene) as the passivation, the E-mode HEMT shows an excellent characteristic. Also, when the VGS of the E-mode HEMT is over 9V, it still shows a good performance.

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Niu, Di, Quan Wang, Wei Li, Changxi Chen, Jiankai Xu, Lijuan Jiang, Chun Feng, et al. "The Influence of the Different Repair Methods on the Electrical Properties of the Normally off p-GaN HEMT." Micromachines 12, no. 2 (January 26, 2021): 131. http://dx.doi.org/10.3390/mi12020131.

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The influence of the repair process on the electrical properties of the normally off p-GaN high-electron-mobility transistor (HEMT) is studied in detail in this paper. We find that the etching process will cause the two-dimensional electron gas (2DEG) and the mobility of the p-GaN HEMT to decrease. However, the repair process will gradually recover the electrical properties. We study different repair methods and different repair conditions, propose the best repair conditions, and further fabricate the p-GaN HEMTs devices. The threshold voltage of the fabricated device is 1.6 V, the maximum gate voltage is 7 V, and the on-resistance is 23 Ω·mm. The device has a good performance, which proves that the repair conditions can be successfully applied to the fabricate of the p-GaN HEMT devices.

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Meneghesso, Gaudenzio, Matteo Meneghini, Augusto Tazzoli, Nicolo' Ronchi, Antonio Stocco, Alessandro Chini, and Enrico Zanoni. "Reliability issues of Gallium Nitride High Electron Mobility Transistors." International Journal of Microwave and Wireless Technologies 2, no. 1 (February 2010): 39–50. http://dx.doi.org/10.1017/s1759078710000097.

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In the present paper we review the most recent degradation modes and mechanisms recently observed in AlGaN/GaN (Aluminum Gallium Nitride/Gallium Nitride). High Electron-Mobility Transistors (HEMTs), as resulting from a detailed accelerated testing campaign, based on reverse bias tests and DC accelerated life tests at various temperatures. Despite the large efforts spent in the last few years, and the progress in mean time to failure values, reliability of GaN HEMTs, and millimeter microwave integrated circuits still represent a relevant issue for the market penetration of these devices. The role of temperature in promoting GaN HEMT failure is controversial, and the accelerating degradation factors are largely unknown. The present paper proposes a methodology for the analysis of failure modes and mechanisms of GaN HEMTs, based on (i) DC and RF stress tests accompanied by an (ii) extensive characterization of traps using deep level transient spectroscopy and pulsed measurements, (iii) detailed analysis of electrical characteristics, and (iv) comparison with two-dimensional device simulations. Results of failure analysis using various microscopy and spectroscopy techniques are presented and failure mechanisms observed at the high electric field values typical of the operation of these devices are reviewed.

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Chang, P. C., K. H. Lee, Z. H. Wang, and S. J. Chang. "AlGaN/GaN High Electron Mobility Transistors with Multi-MgxNy/GaN Buffer." Journal of Nanomaterials 2014 (2014): 1–4. http://dx.doi.org/10.1155/2014/623043.

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We report the fabrication of AlGaN/GaN high electron mobility transistors with multi-MgxNy/GaN buffer. Compared with conventional HEMT devices with a low-temperature GaN buffer, smaller gate and source-drain leakage current could be achieved with this new buffer design. Consequently, the electron mobility was larger for the proposed device due to the reduction of defect density and the corresponding improvement of crystalline quality as result of using the multi-MgxNy/GaN buffer.

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Faqir, M., A. Manoi, T. Mrotzek, S. Knippscheer, M. Massiot, M. Buchta, H. Blanck, S. Rochette, O. Vendier, and M. Kuball. "New GaN Power-Electronics Packaging Solutions: A Thermal Analysis Using Raman Thermography." Journal of Microelectronics and Electronic Packaging 8, no. 3 (July 1, 2011): 110–13. http://dx.doi.org/10.4071/imaps.297.

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Raman thermography measurements were performed on AlGaN/GaN multifinger high electron mobility transistors (HEMTs) to determine their channel temperature at various power levels. The devices were mounted on both silver diamond composite and CuW baseplates, in order to benchmark the thermal performance of novel diamond composite baseplates compared with traditional materials. We illustrate that AlGaN/GaN HEMT devices mounted on silver diamond composite baseplates show peak temperatures that are 50% lower than the peak temperatures exhibited by devices mounted on traditional CuW baseplates. This is a dramatic improvement in terms of heat extraction as a basis to enable longer device lifetimes and better performance. In addition, time-resolved Raman thermography measurements were carried out to obtain the thermal dynamics of devices on the silver-diamond baseplate and on heat diffusion during pulsed device operation. This time-dependent information is of great importance for reliability and failure analyses, as pulsed operation of a HEMT is a typical device operation condition. Finite-element thermal simulations were performed for comparison with experimental results, and good agreement with the experimental data was obtained.

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Shrestha, Niraj Man, Yuen Yee Wang, Yiming Li, and E. Y. Chang. "Simulation Study of AlN Spacer Layer Thickness on AlGaN/GaN HEMT." Himalayan Physics 4 (December 22, 2013): 14–17. http://dx.doi.org/10.3126/hj.v4i0.9419.

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High electron mobility transistor (HEMT)Two-dimensional electron gas (2DEG) formed at AlGaN/GaN interface is a critical part to tune the characteristic of AlGaN/GaN HEMT devices. Introduction of AlN spacer layer in between AlGaN and GaN layer is one of the way to improve 2DEG density, mobility, and drain current. Carrier concentration, mobility and conduction band offset for different spacer layer thickness was simulated by using Silvaco simulation tool. Our device simulations showed that carrier concentration, mobility are enhance on introduction of AlN spacer layer in HEMT. In addition, carrier properties of HEMT also depend on thickness of spacer layer. Our simulation showed that the mobility of 2DEG attains its maximum value at the 0.5 nm thick AlN layer but carrier concentration increases with spacer thickness. Finally, drain current increases with increasing spacer layer thickness and reach maximum value at 1.2nm thick spacer layer.The Himalayan Physics Vol. 4, No. 4, 2013 Page: 14-17 Uploaded date: 12/22/2013

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Chen, Chia Lin, Chih Huan Fang, Yuan Chao Niu, and Yaow Ming Chen. "Impact of Parasitic Capacitor to the GaN HEMT Devices." Applied Mechanics and Materials 764-765 (May 2015): 515–20. http://dx.doi.org/10.4028/www.scientific.net/amm.764-765.515.

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The objective of this paper is to evaluate the impact of the parasitic capacitor to the Gallium-Nitride (GaN) based high-electron-mobility transistor (HEMT). Because of the high switching frequency operation, the parasitic inductor has caught a lot of attention when the GaN HEMT is applied in the high power applications. However, the impact of parasitic capacitor to the GaN HEMT is not discussed in literatures. A prototype circuit is built and tested to evaluate the impacts of parasitic capacitor to the GaN HEMT performance. The results show that the parasitic capacitor can induce voltage spike and damage the GaN HEMT.

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SANO, EIICHI, and TAIICHI OTSUJI. "HEMT-BASED NANOMETER DEVICES TOWARD TERAHERTZ ERA." International Journal of High Speed Electronics and Systems 17, no. 03 (September 2007): 509–20. http://dx.doi.org/10.1142/s0129156407004709.

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The terahertz region is one of the unexplored bands. This paper first reviews the present status of conventional high-speed devices, especially InP-based high electron mobility transistors (HEMTs), and addresses the technological problems facing the goal of terahertz operation. As an alternative approach to solve these problems, we developed a plasmon-resonant photomixer for realizing a coherent terahertz continuous-wave source. Preliminary results on electromagnetic response to impulsive photoexcitation at room temperature are reported briefly.

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Sharbati, Samaneh, Iman Gharibshahian, Thomas Ebel, Ali A. Orouji, and Wulf-Toke Franke. "Analytical Model for Two-Dimensional Electron Gas Charge Density in Recessed-Gate GaN High-Electron-Mobility Transistors." Journal of Electronic Materials 50, no. 7 (April 20, 2021): 3923–29. http://dx.doi.org/10.1007/s11664-021-08842-7.

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AbstractA physics-based analytical model for GaN high-electron-mobility transistors (HEMTs) with non-recessed- and recessed-gate structure is presented. Based on this model, the two-dimensional electron gas density (2DEG) and thereby the on-state resistance and breakdown voltage can be controlled by varying the barrier layer thickness and Al mole fraction in non-recessed depletion-mode GaN HEMTs. The analytical model indicates that the 2DEG charge density in the channel increases from 2.4 × 1012 cm−2 to 1.8 × 1013 cm−2 when increasing the Al mole fraction from x = 0.1 to 0.4 for an experimental non-recessed-gate GaN HEMT. In the recessed-gate GaN HEMT, in addition to these parameters, the recess height can also control the 2DEG to achieve high-performance power electronic devices. The model also calculates the critical recess height for which a normally-ON GaN switch becomes normally-OFF. This model shows good agreement with reported experimental results and promises to become a useful tool for advanced design of GaN HEMTS.

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Chang, Ya-Chun, Yu-Li Ho, Tz-Yan Huang, Ding-Wei Huang, and Chao-Hsin Wu. "Investigation of Normally-Off p-GaN/AlGaN/GaN HEMTs Using a Self-Terminating Etching Technique with Multi-Finger Architecture Modulation for High Power Application." Micromachines 12, no. 4 (April 14, 2021): 432. http://dx.doi.org/10.3390/mi12040432.

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Normally-off p-gallium nitride (GaN) high electron mobility transistor (HEMT) devices with multi-finger layout were successfully fabricated by use of a self-terminating etching technique with Cl2/BCl3/SF6-mixed gas plasma. This etching technique features accurate etching depth control and low surface plasma damage. Several devices with different gate widths and number of fingers were fabricated to investigate the effect on output current density. We then realized a high current enhancement-mode p-GaN HEMT device with a total gate width of 60 mm that exhibits a threshold voltage of 2.2 V and high drain current of 6.7 A.

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XU, DONG, XIAOPING YANG, P. SEEKELL, L. MT PLEASANT, R. ISAAK, W. M. T. KONG, G. CUEVA, et al. "50-NM SELF-ALIGNED HIGH ELECTRON-MOBILITY TRANSISTORS ON GaAs SUBSTRATES WITH EXTREMELY HIGH EXTRINSIC TRANSCONDUCTANCE AND HIGH GAIN." International Journal of High Speed Electronics and Systems 20, no. 03 (September 2011): 393–98. http://dx.doi.org/10.1142/s0129156411006672.

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We report the design, fabrication and characterization of metamorphic high electron-mobility transistors (MHEMTs) with self-aligned ohmic electrodes. In this work, asymmetrically recessed 50-nm Γ-gates have been successfully used as the shadow mask for ohmic metal deposition. Extremely high extrinsic transconductance over a wide drain bias from 0.1 to 1.25 V can be made possible by fabricating devices with small gate-source spacing, small source-drain spacing, and the non-alloyed ohmic. Measured maximum extrinsic transconductance of 3 S/mm is a new record for all HEMT devices on GaAs and equals the best results from InP -based HEMTs. The same devices also show a voltage gain of 22, maximum stable gain of 10.8 dB at 110 GHz, and breakdown voltage of 4.3 V, which all are the highest among any self-aligned HEMTs based on InGaAs channel. The outstanding performance is the result of the seamless integration of the asymmetric gate recess and Γ-gate-based self-aligned ohmic process.

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Faqir, M., A. Manoi, T. Mrotzek, S. Knippscheer, M. Massiot, M. Buchta, H. Blanck, S. Rochette, O. Vendier, and M. Kuball. "New GaN Power-Electronics Packaging Solutions: A Thermal Analysis using Raman Thermography." International Symposium on Microelectronics 2010, no. 1 (January 1, 2010): 000446–49. http://dx.doi.org/10.4071/isom-2010-wa3-paper3.

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Raman thermography measurements were performed on AlGaN/GaN multi-finger high electron mobility transistors (HEMTs) to determine their channel temperature at various power levels. The devices were mounted on both silver diamond composite and CuW base plates, in order to benchmark the thermal performance of novel diamond composite base plates compared to traditional materials. We illustrate that AlGaN/GaN HEMT devices mounted on silver diamond composite base plates show peak temperatures which are 50% lower than the peak temperatures exhibited by devices mounted on traditional CuW base plates. This is a dramatic improvement in terms of heat extraction, as basis to enabling longer device life-times and better performances. In addition, time-resolved Raman thermography measurements were carrier out to obtain thermal dynamics of devices on the silver-diamond base plate and on heat diffusion during pulsed device operation. This time-dependent information is of great importance for reliability and failure analyses, as pulsed operation of a HEMT is a typically device operation condition. Finite-element thermal simulations were performed for comparison with the experimental results, and good agreement with the experimental data was obtained.

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Lukić, P. M., R. M. Ramović, and Rajko M. Šašić. "HEMT Carrier Mobility Analytical Model." Materials Science Forum 494 (September 2005): 43–48. http://dx.doi.org/10.4028/www.scientific.net/msf.494.43.

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In this paper a new analytical carrier mobility model of a heterostructure unipolar transistor, High Electron Mobility Transistor (HEMT), is presented. The influence of the two dimensional electron gas confined in a HEMT channel on the device carrier mobility, is considered. The mobility dependence on temperature is also included in the model. Advantages of this model are its simplicity and straightforward implementation. Besides, it promises to be applied to quite different types of HEMTs. The model was tested. The results derived from simulations based on the proposed model are in very good agreement with the already known experimental data and theoretically obtained ones, available in literature.

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Subash, T. D., T. Gnanasekaran, and P. Deepthi Nair. "Analytical modeling of AlInSb/InSb MOS gate HEMT structure with improved performance." International Journal of Modeling, Simulation, and Scientific Computing 07, no. 03 (August 23, 2016): 1672001. http://dx.doi.org/10.1142/s1793962316720016.

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The performance of AlInSb/InSb heterostructure with various parameters is considered with T-Cad simulation. As the heterojunctions are having more advantageous properties that is a real support for so many application such as solar cells, semiconductor cells and transistors. Special properties of semiconductors are discussed here with various parameters that are depending up on the performance of accurate device [Pardeshi H., Pati S. K., Raj G., Mohankumar N., Sarkar C. K., J. Semicond. 33(12):124001-1–124001-7, 2012]. The maximum drain current density is achieved with improving the density of two-dimensional electron gas (2DEG) and with high velocity. High electron mobility transistor (HEMT) structure is used with the different combinations of layers which have different bandgaps. Parameters such as electron mobility, bandgap, dielectric constant, etc., are considered differently for each layer [Zhang A., Zhang L., Tang Z., IEEE Trans. Electron Devices 61(3):755–761, 2014]. The high electron mobility electrons are now widely used in so many applications. The proposed work of AlInSb/InSb heterostructure implements the same process which will be a promise for future research works.

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Sun, Haifeng, Diego Marti, Stefano Tirelli, Andreas R. Alt, Hansruedi Benedickter, and C. R. Bolognesi. "Millimeter-wave GaN-based HEMT development at ETH-Zürich." International Journal of Microwave and Wireless Technologies 2, no. 1 (February 2010): 33–38. http://dx.doi.org/10.1017/s1759078710000164.

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We review the AlGaN/GaN high electron mobility transistor (HEMT) activities in the Millimeter-Wave Electronics Group at ETH-Zürich. Our group's main thrust in the AlGaN/GaN arena is the extension of device bandwidth to higher frequency bands. We demonstrated surprising performances for AlGaN/GaN HEMTs grown on high-resistivity (HR) silicon (111) substrates, and extended cutoff frequencies of 100 nm gate devices well into the millimeter (mm)-wave domain. Our results narrow the performance gap between GaN-on-SiC (or sapphire) and GaN-on-silicon and establish GaN-on-Si as a viable technology for low-cost mm-wave electronics. We here contrast the difference in behaviors observed in our laboratory between nominally identical devices built on high-resistivity silicon (HR-Si) and on sapphire substrates; we show high-speed devices with high-cutoff frequencies and breakdown voltages which combine fT,MAX × BV products as high as 5–10 THz V, and show AlGaN/GaN HEMTs with fT values exceeding 100 GHz on HR-Si. Although the bulk of our activities have so far focused on AlGaN/GaN HEMTs on HR-Si, our process produces excellent device performances when applied to GaN HEMTs on SiC as well: 100 nm gate transistors with fT > 125 GHz have been realized at ETH-Zürich.

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Lee, Chwan Ying, Yung Hsiang Chen, Lurng Shehng Lee, Chien Chung Hung, Cheng Tyng Yen, Suh Fang Lin, Rong Xuan, Wei Hung Kuo, Tzu Kun Ku, and Ming Jinn Tsai. "Performance Comparison of GaN Power Transistors and Investigation on the Device Design Issues." Materials Science Forum 717-720 (May 2012): 1303–6. http://dx.doi.org/10.4028/www.scientific.net/msf.717-720.1303.

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One normally-on N-channel AlGaN/GaN device and two types of normally-off GaN devices have been studied. The normally-on device with Sapphire substrate shows good Idsatand breakdown characteristics, but the gate leakage current is quite large. The first normally-off GaN hybrid metal insulator semiconductor – high electron mobility transistor (MIS-HEMT) grown on Si substrate exhibits good performance with positive threshold voltage of 3V and the breakdown voltage of over 1800V. However the second normally-off GaN MOSFET structure is rather difficult to exhibit good blocking characteristic compared to GaN MIS-HEMT device due to inadequate device design.

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Jang, Kyu-Won, In-Tae Hwang, Hyun-Jung Kim, Sang-Heung Lee, Jong-Won Lim, and Hyun-Seok Kim. "Thermal Analysis and Operational Characteristics of an AlGaN/GaN High Electron Mobility Transistor with Copper-Filled Structures: A Simulation Study." Micromachines 11, no. 1 (December 31, 2019): 53. http://dx.doi.org/10.3390/mi11010053.

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In this study, we investigated the operational characteristics of AlGaN/GaN high electron mobility transistors (HEMTs) by applying the copper-filled trench and via structures for improved heat dissipation. Therefore, we used a basic T-gate HEMT device to construct the thermal structures. To identify the heat flow across the device structure, a thermal conductivity model and the heat transfer properties corresponding to the GaN, SiC, and Cu materials were applied. Initially, we simulated the direct current (DC) characteristics of a basic GaN on SiC HEMT to confirm the self-heating effect on AlGaN/GaN HEMT. Then, to verify the heat sink effect of the copper-filled thermal structures, we compared the DC characteristics such as the threshold voltage, transconductance, saturation current, and breakdown voltage. Finally, we estimated and compared the lattice temperature of a two-dimensional electron gas channel, the vertical lattice temperature near the drain-side gate head edge, and the transient thermal analysis for the copper-filled thermal trench and via structures. Through this study, we could optimize the operational characteristics of the device by applying an effective heat dissipation structure to the AlGaN/GaN HEMT.

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Малеев, Н. А., А. П. Васильев, А. Г. Кузьменков, М. А. Бобров, М. М. Кулагина, С. И. Трошков, С. Н. Малеев, et al. "InAlAs/InGaAs/InP HEMTs с композитным каналом и улучшенными пробивными характеристиками." Письма в журнал технической физики 45, no. 21 (2019): 29. http://dx.doi.org/10.21883/pjtf.2019.21.48470.17961.

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High-electron mobility transistor (HEMT) with improved breakdown characteristics has been developed. Composite InGaAs channel structure was used in combination with fully selective double recess device fabrication process. HEMTs with T-gate length of 120 nm and width 4x30 m demonstrate maximum extrinsic transconductance of 810 mS/mm, maximum drain current density of 460 mA/mm and gate-drain reverse breakdown voltages as high as 8–10 V. Devices cut-off frequency exceed 115 GHz. Because of increased breakdown voltage and fully selective double recess fabrication process designed HEMTs are promising for medium power mm-wave MMIC amplifiers.

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Kong, Cen, Jian Jun Zhou, Jin Yu Ni, Yue Chan Kong, and Tang Sheng Chen. "High Breakdown Voltage GaN Power HEMT on Si Substrate." Advanced Materials Research 805-806 (September 2013): 948–53. http://dx.doi.org/10.4028/www.scientific.net/amr.805-806.948.

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GaN high electronic mobility transistor (HEMT) was fabricated on silicon substrate. A breakdown voltage of 800V was obtained without using field plate technology. The fabrication processes were compatible with the conventional GaN HEMTs fabrication processes. The length between drain and gate (Lgd) has a greater impact on breakdown voltage of the device. A breakdown voltage of 800V with maximum current density of 536 mA/mm was obtained while Lgd was 15μm and the Wg was 100μm. The specific on-state resistance of this devices was 1.75 mΩ·cm2, which was 85 times lower than that of silicon MOSFET with same breakdown voltage. The results establish the foundation of low cost GaN HEMT power electronic devices.

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Luo, Qian, Jiang Feng Du, Xiang Wang, Ning Ning, Yang Liu, and Qi Yu. "An Analytical Model for Field-Plate Optimization in High Electron Mobility Transistor." Advanced Materials Research 529 (June 2012): 33–36. http://dx.doi.org/10.4028/www.scientific.net/amr.529.33.

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An analytical model for field-plate (FP) optimization in high electron mobility transistor (HEMT) is reported. With the potential distribution in device’s channel being modeled in terms of physical parameters, the two critical parameters of FP, i.e., the insulator thickness and the FP length, are optimized respectively. Using the model, the optimization of the FP structure in a typical undoped AlGaN/GaN HEMT is described in detail.

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Pullabhatla, Sai Kiran, Phaneendra Babu Bobba, and Satyavani Yadlapalli. "Comparison of GAN, SIC, SI Technology for High Frequency and High Efficiency Inverters." E3S Web of Conferences 184 (2020): 01012. http://dx.doi.org/10.1051/e3sconf/202018401012.

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Power semiconductor devices plays a major role in efficient power conversion. As we have Silicon (Si), Silicon Carbide (SiC) and Gallium Nitride (GaN) based power devices, GaN technologies are ideal for working in high frequency power electronic systems (in MHz). Because the GaN has superior electron mobility and bandgap than the SiC and Si it has superior characteristics like low conduction losses, high switching rate so that there is better power efficiency than SiC, Si based inverter. Here we are using the Gan based High-Electron-Mobility Transistor (HEMT) and SiC and Si based mosfet in the inverter. The proposed inverter of different topologies is designed to transfer the power at >1MHz range. Comparison of the three different switches is done by the output power and the efficiency of the inverter. This paper presents the SPICE simulation results of the class d and class e inverter of output power 1KW.

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Mohankumar, N., A. Mohanbabu, S. Baskaran, P. Anandan, N. Anbuselvan, and P. Bharathi Vikkiraman. "Modeling of Sheet Carrier Density, DC and Transconductance of Novel InxAl1-XN/GaN-Based HEMT Structures." Advanced Materials Research 1105 (May 2015): 99–104. http://dx.doi.org/10.4028/www.scientific.net/amr.1105.99.

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In this paper, we propose a physics-based analytical model of novel InAlN/GaN High Electron Mobility Transistor (HEMT) by considering the quasi-triangular quantum well with minimal empirical parameters. The derived model is compared for different short and long gate length devices. The results are calibrated and verified with experimental data over a full range for gate and drain applied voltages. Significant improvement in ns, drain Current, and transconductance are observed for InAlN HEMT making it suitable for nanoscale and microwave analysis in circuit design. Therefore, the proposed model can deal directly with device/physical parameters, and it can be expressed by a very small number of model parameters.

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Chander, Subhash, Partap Singh, Samuder Gupta, D. S. Rawal, and Mridula Gupta. "Self heating Effects in GaN High Electron Mobility Transistor for Different Passivation Material." Defence Science Journal 70, no. 5 (October 8, 2020): 511–14. http://dx.doi.org/10.14429/dsj.70.16360.

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In this paper effect of self-heating has been studied of AlGaN/GaN high electron mobility transistor (HEMT) for different passivation layers which is promising device for high power at high frequencies. The different passivation layers used are aluminium oxide (Al2O3), silicon nitride (SiN) and silicon dioxide (SiO2). The device GaN HEMT has been simulated and characterised for its thermal behaviour by the distribution of lattice temperature inside the device using device simulation tool ATLAS from SILVACO. The transfer and output characteristics with and without self-heating has been studied for electrical characterisation. The channel temperature for different passivation observed is 448 K, 456 K and 471 K forAl2O3, SiN and SiO2 respectively. The observed different temperatures are due to difference in their thermal conductivity. This channel temperature information is critical to study the reliability of the device at high power levels.

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Othman, Nurul Aida Farhana, Sharidya Rahman, Sharifah Fatmadiana Wan Muhamad Hatta, Norhayati Soin, Brahim Benbakhti, and Steven Duffy. "Design optimization of the graded AlGaN/GaN HEMT device performance based on material and physical dimensions." Microelectronics International 36, no. 2 (April 1, 2019): 73–82. http://dx.doi.org/10.1108/mi-09-2018-0057.

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Purpose To design and optimize the traditional aluminum gallium nitride/gallium nitride high electron mobility transistor (HEMT) device in achieving improved performance and current handling capability using the Synopsys’ Sentaurus TCAD tool. Design/methodology/approach Varying material and physical considerations, specifically investigating the effects of graded barriers, spacer interlayer, material selection for the channel, as well as study of the effects in the physical dimensions of the HEMT, have been extensively carried out. Findings Critical figure-of-merits, specifically the DC characteristics, 2DEG concentrations and mobility of the heterostructure device, have been evaluated. Significant observations include enhancement of maximum current density by 63 per cent, whereas the electron concentration was found to propagate by 1,020 cm−3 in the channel. Practical implications This work aims to provide tactical optimization to traditional heterostructure field effect transistors, rendering its application as power amplifiers, Monolithic Microwave Integrated Circuit (MMICs) and Radar, which requires low noise performance and very high radio frequency design operations. Originality/value Analysis in covering the breadth and complexity of heterostructure devices has been carefully executed through extensive TCAD modeling, and the end structure obtained has been optimized to provide best performance.

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RafaelValdivia, G., T. FernandezIbanez, J. Rodriguez-Tellez, A. TazonPuente, and A. MediavillaSanchez. "Measurement of Mobility in HEMT Devices Using High-Order Derivatives." IEEE Transactions on Electron Devices 51, no. 1 (January 2004): 1–7. http://dx.doi.org/10.1109/ted.2003.820938.

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Rafael, G., T. Fernández, J. Rodriguez-Tellez, A. Tazón, and A. Mediavilla. "High-order derivatives in measurement of mobility in HEMT devices." Electronics Letters 40, no. 11 (2004): 700. http://dx.doi.org/10.1049/el:20040333.

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Chen, Yuan-Ming, Hsien-Cheng Lin, Kuan-Wei Lee, and Yeong-Her Wang. "Inverted-Type InAlAs/InAs High-Electron-Mobility Transistor with Liquid Phase Oxidized InAlAs as Gate Insulator." Materials 14, no. 4 (February 18, 2021): 970. http://dx.doi.org/10.3390/ma14040970.

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An inverted-type InAlAs/InAs metal-oxide-semiconductor high-electron-mobility transistor (MOS-HEMT) with liquid phase oxidized (LPO) InAlAs as the gate insulator is demonstrated. A thin InAs layer is inserted in the sub-channel layers of InGaAs to enhance the device performance. The proposed inverted-type InAlAs/InAs MOS-HEMT exhibits an improved maximum drain current density, higher transconductance, lower leakage current density, suppressed noise figures, and enhanced associated gain compared to the conventional Schottky-gate HEMT. Employing LPO to generate MOS structure improves the surface states and enhances the energy barrier. These results reveal that the proposed inverted-type InAlAs/InAs MOS-HEMT can provide an alternative option for device applications.

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Shen, Zhan Wei, Feng Zhang, Sima Dimitrijev, Ji Sheng Han, Li Xin Tian, Guo Guo Yan, Zheng Xin Wen, et al. "Prediction of High-Density and High-Mobility Two-Dimensional Electron Gas at Al_xGa_1-xN/4H-SiC Interface." Materials Science Forum 897 (May 2017): 719–22. http://dx.doi.org/10.4028/www.scientific.net/msf.897.719.

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This work presents theoretical demonstration of two-dimensional electron gas (2DEG) at the interface between Al0.2Ga0.8N and 4H-SiC, based on the self-consistent solution of Schrödinger–Poisson equations. High sheet carrier density of 1.1×1013 cm-2 was obtained in the Al0.2Ga0.8N/4H-SiC heterostructure, which is comparable to the electron concentration in Al0.2Ga0.8N/GaN heterostructure. The current–voltage characteristics of a high-electron-mobility transistor (HEMT), based on the Al0.2Ga0.8N/4H-SiC heterostructure, show a saturated drain current of 1.5 A/mm at the gate voltage of 2 V and the transconductance of 194 mS/mm at -3.95 V. In spite of interface-roughness scattering and phonon scattering, the 2DEG at the AlxGa1-xN/4H-SiC interface exhibits high electron mobility values of 3365 cm2/ (V·s) at 77K and 1120 cm2/ (V·s) at 300K. These results indicate that AlxGa1-xN/4H-SiC heterostructure can significantly improve the mobility of SiC based power switching devices.

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Zakarya, Kourdi, and Abdelkhader Hamdoun. "A modeling and performance of the triple field plate HEMT." International Journal of Power Electronics and Drive Systems (IJPEDS) 10, no. 1 (March 1, 2019): 398. http://dx.doi.org/10.11591/ijpeds.v10.i1.pp398-405.

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We present this work by two steps. In the first one, the new structure proposed of the FP-HEMTs device (Field plate High Electron Mobility Transistor) with a T-gate on an 4H-SIC substrate to optimize these electrical performances, multiple field-plates were used with aluminum oxide to split the single electric field peak into several smaller peaks, and as passivation works to reduce scaling leakage current. In the next, we include a modeling of a simulation in the Tcad-Silvaco Software for realizing the study of the influence of negative voltage applied to gate T-shaped in OFF state time and high power with ambient temperature, the performance differences between the 3FP and the SFP devices are discussed in detail.

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Lin, Wei, Maojun Wang, Haozhe Sun, Bing Xie, Cheng P. Wen, Yilong Hao, and Bo Shen. "Suppressing Buffer-Induced Current Collapse in GaN HEMTs with a Source-Connected p-GaN (SCPG): A Simulation Study." Electronics 10, no. 8 (April 15, 2021): 942. http://dx.doi.org/10.3390/electronics10080942.

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Carbon doping in the buffer of AlGaN/GaN high-electron-mobility transistors (HEMTs) leads to the notorious current collapse phenomenon. In this paper, an HEMT structure with a source-connected p-GaN (SCPG) embedded in the carbon-doped semi-insulating buffer is proposed to suppress the buffer-induced current collapse effect. Two-dimensional transient simulation was carried out to show the successful suppression of buffer-induced current collapse in the SCPG-HEMTs compared with conventional HEMTs. The mechanism of suppressing dynamic on-resistance degradation by ejecting holes from the SCPG into the high resistive buffer layer after off-state stress is illustrated based on energy band diagrams. This paper contributes an innovative device structure to potentially solve the buffer-induced degradation of the dynamic on-resistance in GaN power devices.

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Jatal, Wael, Uwe Baumann, Heiko O. Jacobs, Frank Schwierz, and Jörg Pezoldt. "Tri-Gate Al_0.2Ga_0.8N/AlN/GaN HEMTs on SiC/Si-Substrates." Materials Science Forum 858 (May 2016): 1174–77. http://dx.doi.org/10.4028/www.scientific.net/msf.858.1174.

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A nanochannel array structure was applied to realize enhancement-mode high electron mobility transistors based on AlGaN/AlN/GaN-heterostructures grown on Si substrates using a SiC transition layer. The fabricated nanochannel array HEMT, consisting of 78 channels connected in parallel with a channel width of 100 nm defined by electron-beam lithography and dry etching, shows a threshold voltage of 0.35 V. The high electron mobility transistors with LG= 0.2 μm had a maximum drain current density of 445 mA/mm and a peak extrinsic tranconductance of 235 mS/mm. A unity current gain cut-off frequency of 30 GHz and maximum oscillation frequency of 40 GHz were measured on these devices.

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Boursali, Amin, Ahlam Guen-Bouazza, and Choukria Sayah. "DC and RF characteristics of 20 nm gate length InAlAs/InGaAs/InP HEMTs for high frequency application." International Journal of Electrical and Computer Engineering (IJECE) 10, no. 2 (April 1, 2020): 1248. http://dx.doi.org/10.11591/ijece.v10i2.pp1248-1254.

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lnAlAs/lnGaAs/InP high electron mobility transistor (HEMT) offers excellent high frequency operation.In this work,the DC and RF performance of a 20 nm gate length enhancement mode InAlAs/InGaAs/InP high electron mobility transistor (HEMT) on InP substrate are presented.The SILVACO-TCAD simulations performed at room temperature using the appropriate model sshowed that the studied device exhibit excellent pinch-off characteristics, with a maximum transconductance of 1100ms/mm, a threshold voltage of 0,62V, and an Ion/Ioff ratio of 2.106. The cut-off frequency and maximum frequency of oscillation are 980 GHz and 1.3THz respectively. These promising results allow us to affirm that this device is intended to be used in high frequency applications.

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Chvála, Aleš, Lukáš Nagy, Juraj Marek, Juraj Priesol, Daniel Donoval, Alexander Šatka, Michal Blaho, Dagmar Gregušová, and Ján Kuzmík. "Device and Circuit Models of Monolithic InAlN/GaN NAND and NOR Logic Cells Comprising D- and E-Mode HEMTs." Journal of Circuits, Systems and Computers 28, supp01 (December 1, 2019): 1940009. http://dx.doi.org/10.1142/s0218126619400097.

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This paper presents monolithic integrated InAlN/GaN NAND and NOR logic cells comprising depletion-mode, enhancement-mode and dual-gate enhancement-mode high electron mobility transistors (HEMTs). The designed NAND and NOR logic cells consist of the depletion-mode and enhancement-mode HEMT transistors integrated onto a single die. InAlN/GaN-based NAND and NOR logic cells with good static and dynamic performance are demonstrated for the first time. Calibrated static and dynamic electrophysical models are proposed for 2D device simulations in Sentaurus Device environment. Sentaurus Device mixed-mode setup interconnects the transistors to NAND and NOR logic circuits which allows analysis and characterization of the devices as a complex system. Circuit models of depletion-mode, enhancement-mode and dual-gate HEMTs are designed and calibrated by experimental results and 2D device simulations. The proposed models exhibit highly accurate results.

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35

Lenka, T. R., and A. K. Panda. "Self-Consistent Subband Calculations of Al_xGa_1-xN/(AlN)/GaN-Based High Electron Mobility Transistor." Advanced Materials Research 159 (December 2010): 342–47. http://dx.doi.org/10.4028/www.scientific.net/amr.159.342.

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In this paper, there is an attempt to present the two dimensional electron gas (2DEG) transport characteristics of AlxGa1-xN/(AlN)/GaN-based High Electron Mobility Transistor (HEMT) using a self-consistent numerical method for calculating the conduction-band profile and subband structure. The subband calculations take into account the piezoelectric and spontaneous polarization effects and the Hartree and exchange-correlation interaction. Here the dependency of conduction band profile, subband energies, 2DEG sheet concentration and sheet resistance on various Al mole fractions of AlxGa1-xN barrier layer are presented by incorporating simulation as well as available experimental data. Introduction of very thin binary AlN layer at the heterojunction of AlxGa1-xN/GaN resulting high mobility at high sheet charge densities by increasing the effective and decreasing alloy disorder scattering. Devices based on this structure exhibit good DC and RF performance as an increase of . Owing to high 2DEG density , the proposed device leads to operate in microwave and millimeter wave applications.

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36

Liu, Wenyuan, Lin Zhu, Feng Feng, Wei Zhang, Qi-Jun Zhang, Qian Lin, and Gaohua Liu. "A Time Delay Neural Network Based Technique for Nonlinear Microwave Device Modeling." Micromachines 11, no. 9 (August 31, 2020): 831. http://dx.doi.org/10.3390/mi11090831.

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This paper presents a nonlinear microwave device modeling technique that is based on time delay neural network (TDNN). The proposed technique can accurately model the nonlinear microwave devices when compared to static neural network modeling method. A new formulation is developed to allow for the proposed TDNN model to be trained with DC, small-signal, and large signal data, which can enhance the generalization of the device model. An algorithm is formulated to train the proposed TDNN model efficiently. This proposed technique is verified by GaAs metal-semiconductor-field-effect transistor (MESFET), and GaAs high-electron mobility transistor (HEMT) examples. These two examples demonstrate that the proposed TDNN is an efficient and valid approach for modeling various types of nonlinear microwave devices.

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37

Darwish, Ali M., H. Alfred Hung, Edward Viveiros, and Amr A. Ibrahim. "Broadband AlGaN/GaN MMIC amplifier." International Journal of Microwave and Wireless Technologies 3, no. 4 (March 18, 2011): 399–404. http://dx.doi.org/10.1017/s1759078711000195.

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A broadband Monolithic Microwave Integrated Circuit (MMIC) amplifier, with 12 ± 2 dB gain across the 0.1–27 GHz band has been demonstrated using the AlGaN/GaN on SiC technology. The amplifier design employs a non-conventional, series-DC/RF-High Electron Mobility Transistor (HEMT) configuration. This configuration provides an alternative design to the conventional traveling-wave amplifier (TWA). It results in a smaller MMIC chip size, and extends amplifier gain to the low-frequency region. The amplifier MMIC utilizes four HEMT devices in series and could be biased at voltages up to 120 V.

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LEE, JAESUN, DONGMIN LIU, HYEONGNAM KIM, MICHAEL L. SCHUETTE, WU LU, JEFFREY S. FLYNN, and GEORGE R. BRANDES. "FABRICATION OF SELF-ALIGNED T-GATE AlGaN/GaN HIGH ELECTRON MOBILITY TRANSISTORS." International Journal of High Speed Electronics and Systems 14, no. 03 (September 2004): 805–9. http://dx.doi.org/10.1142/s0129156404002867.

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Self-aligned AlGaN/GaN high electron mobility transistors (HEMTs) are fabricated and the direct current and radio frequency small signal performance of self-aligned devices is characterized in comparison with non-self-aligned devices. An ultra-thin Ti/Al/Ti/Au ohmic metal scheme is used for gate to source and drain self-alignment. To suppress the gate leakage current, the ohmic contact annealing of self-aligned devices is performed in a furnace. The self-aligned devices with 0.25 μm gate-length and 100 μm gate-width exhibit good pinch-off characteristics. The maximum drain current at a gate bias of 1 V is 620 mA/mm for self-aligned HEMTs, and 400 mA/mm for non-self-aligned devices, respectively. A maximum extrinsic transconductance of 146 mS/mm is measured in self-aligned devices, while non-self-aligned HEMTs show only a peak g m of 92 mS/mm. The self-aligned devices exhibit an extrinsic f T of 39 GHz and an f MAX of 130 GHz, whereas non-self-aligned HEMTs show an f T of 15 GHz and an f MAX of 35 GHz.

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Waltereit, Patrick, Wolfgang Bronner, Rüdiger Quay, Michael Dammann, Rudolf Kiefer, Wilfried Pletschen, Stefan Müller, et al. "AlGaN/GaN epitaxy and technology." International Journal of Microwave and Wireless Technologies 2, no. 1 (February 2010): 3–11. http://dx.doi.org/10.1017/s175907871000005x.

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We present an overview on epitaxial growth, processing technology, device performance, and reliability of our GaN high electron mobility transistors (HEMTs) manufactured on 3- and 4-in. SiC substrates. Epitaxy and processing are optimized for both performance and reliability. We use three different gate lengths, namely 500 nm for 1–6 GHz applications, 250 nm for devices between 6 and 18 GHz, and 150 nm for higher frequencies. The developed HEMTs demonstrate excellent high-voltage stability, high power performance, and large DC to RF conversion efficiencies for all gate lengths. On large gate width devices for base station applications, an output power beyond 125 W is achieved with a power added efficiency around 60% and a linear gain around 16 dB. Reliability is tested both under DC and RF conditions with supply voltage of 50 and 30 V for 500 and 250 nm gates, respectively. DC tests on HEMT devices return a drain current change of just about 10% under IDQ conditions. Under RF stress the observed change in output power density is below 0.2 dB after more than 1000 h for both gate length technologies.

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Ki, Ra-Seong, Kwang-Seok Seo, and Ho-Young Cha. "Thermal Boundary Resistance Extraction of GaN-on-Diamond Substrate from Transmission Line Method Pattern Using Micro-Raman Spectroscopy and Thermal Simulation." Journal of Nanoscience and Nanotechnology 21, no. 8 (August 1, 2021): 4434–37. http://dx.doi.org/10.1166/jnn.2021.19414.

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Heat dissipation properties are very important in AlGaN/GaN RF high electron mobility transistor (HEMT) devices operating at high frequency and high power. Therefore, in order to extract the thermal conductivity of the substrate and device, which are essential for the analysis of the heat dissipation characteristics, various methods of extraction were attempted. And this experiments were conducted in parallel with micro-raman measurement and thermal simulation. As a result, it was possible to extract the thermal conductivity of each GaN-on-diamond epi layer by matching the thermal simulation data and the shift of the micro-raman peak according to various operating states and temperatures of the transmission line method (TLM) pattern. In particular, we tried to extract the thermal boundary resistance (TBR) of the interface layer (SiNx) for adhesion between GaN and diamond, which greatly affects the thermal conductivity of the device, and successfully extracted the following thermal conductivity value of KTBR = 3.162·(T/300)−0.8 (W/mK) from GaN and diamond interface layer.

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Cha, Kwang-Hyung, Chang-Tae Ju, and Rae-Young Kim. "Analysis and Evaluation of WBG Power Device in High Frequency Induction Heating Application." Energies 13, no. 20 (October 14, 2020): 5351. http://dx.doi.org/10.3390/en13205351.

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A device suitability analysis is performed herein by comparing the performance of a silicon carbide (SiC) metal-oxide-semiconductor-field-effect transistor (MOSFET) and a gallium nitride (GaN) high-electron mobility transistor (HEMT), which are wide-bandgap (WBG) power semiconductor devices in induction heating (IH) systems. The WBG device presents advantages such as high-speed switching owing to its excellent physical properties, and when it is applied to the IH system, a high output power can be achieved through high-frequency driving. To exploit these advantages effectively, a suitability analysis comparing SiC and GaN with IH systems is required. In this study, SiC MOSFET and GaN HEMT are applied to the general half-bridge series resonant converter topology, and comparisons of the conduction loss, switching loss, reverse conduction loss, and thermal performance considering the characteristics of the device and the system conditions are performed. Accordingly, the device suitability in an IH system is analyzed. To verify the device conformance analysis, a resonant converter prototype with SiC and GaN rated at 650 V is constructed. The analysis is verified by an experimental comparison of power loss and thermal performance.

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Choi, Yeo-Jin, Jae-Hoon Lee, Jin-Seok Choi, Sung-Jin An, Young-Min Hwang, Jae-Seung Roh, and Ki-Sik Im. "Improved Noise and Device Performances of AlGaN/GaN HEMTs with In Situ Silicon Carbon Nitride (SiCN) Cap Layer." Crystals 11, no. 5 (April 27, 2021): 489. http://dx.doi.org/10.3390/cryst11050489.

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We investigated the effects of in situ silicon carbon nitride (SiCN) cap layer of AlGaN/GaN high-electron mobility transistors (HEMTs) on DC, capacitance-voltage (C-V) and low-frequency noise (LFN). The proposed device with SiCN cap layer exhibited enhanced drain current, reduced gate leakage current, low interface trap density (Dit), and high on/off ratio thanks to the passivation effect, compared to the device without SiCN cap layer. Both devices clearly showed 1/f noise behavior with carrier number fluctuations (CNF), regardless of the existence of SiCN cap layer. The proposed device presented the relative low trap density (Nit) and reduced access noise due to the effective surface passivation in source-drain access region compared to the device without SiCN cap layer. From the improved DC, C-V and noise results of the proposed device, the in situ SiCN cap layer plays an important role in the passivation layer and gate oxide layer in AlGaN/GaN HEMT.

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Hong, Sejun, Abu ul Hassan Sarwar Rana, Jun-Woo Heo, and Hyun-Seok Kim. "DC Characteristics of AlGaN/GaN HEMTs Using a Dual-Gate Structure." Journal of Nanoscience and Nanotechnology 15, no. 10 (October 1, 2015): 7467–71. http://dx.doi.org/10.1166/jnn.2015.11135.

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Multiple techniques such as fluoride-based plasma treatment, a p-GaN or p-AlGaN gate contact, and a recessed gate structure have been employed to modulate the threshold voltage of AlGaN/GaN-based high-electron-mobility transistors (HEMTs). In this study, we present dual-gate AlGaN/GaN HEMTs grown on a Si substrate, which effectively shift the threshold voltage in the positive direction. Experimental data show that the threshold voltage is shifted from −4.2 V in a conventional single-gate HEMT to −2.8 V in dual-gate HEMTs. It is evident that a second gate helps improve the threshold voltage by reducing the two-dimensional electron gas density in the channel. Furthermore, the maximum drain current, maximum transconductance, and breakdown voltage values of a single-gate device are not significantly different from those of a dual-gate device. For the fabricated single- and dual-gate devices, the values of the maximum drain current are 430 mA/mm and 428 mA/mm, respectively, whereas the values of the maximum transconductance are 83 mS/mm and 75 mS/mm, respectively.

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Zeng, Fanming, Judy An, Guangnan Zhou, Wenmao Li, Hui Wang, Tianli Duan, Lingli Jiang, and Hongyu Yu. "A Comprehensive Review of Recent Progress on GaN High Electron Mobility Transistors: Devices, Fabrication and Reliability." Electronics 7, no. 12 (December 3, 2018): 377. http://dx.doi.org/10.3390/electronics7120377.

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GaN based high electron mobility transistors (HEMTs) have demonstrated extraordinary features in the applications of high power and high frequency devices. In this paper, we review recent progress in AlGaN/GaN HEMTs, including the following sections. First, challenges in device fabrication and optimizations will be discussed. Then, the latest progress in device fabrication technologies will be presented. Finally, some promising device structures from simulation studies will be discussed.

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Ma, Chao-Tsung, and Zhen-Huang Gu. "Review of GaN HEMT Applications in Power Converters over 500 W." Electronics 8, no. 12 (November 23, 2019): 1401. http://dx.doi.org/10.3390/electronics8121401.

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Because of the global trends of energy demand increase and decarbonization, developing green energy sources and increasing energy conversion efficiency are recently two of the most urgent topics in energy fields. The requirements for power level and performance of converter systems are continuously growing for the fast development of modern technologies such as the Internet of things (IoT) and Industry 4.0. In this regard, power switching devices based on wide-bandgap (WBG) materials such as silicon carbide (SiC) and gallium nitride (GaN) are fast maturing and expected to greatly benefit power converters with complex switching schemes. In low- and medium-voltage applications, GaN-based high-electron-mobility transistors (HEMTs) are superior to conventional silicon (Si)-based devices in terms of switching frequency, power rating, thermal capability, and efficiency, which are crucial factors to enhance the performance of advanced power converters. Previously published review papers on GaN HEMT technology mainly focused on fabrication, device characteristics, and general applications. To realize the future development trend and potential of applying GaN technology in various converter designs, this paper reviews a total of 162 research papers focusing on GaN HEMT applications in mid- to high-power (over 500 W) converters. Different types of converters including direct current (DC)–DC, alternating current (AC)–DC, and DC–AC conversions with various configurations, switching frequencies, power densities, and system efficiencies are reviewed.

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Tonisch, Katja, Wael Jatal, Ralf Granzner, Mario Kittler, Uwe Baumann, Frank Schwierz, and Jörg Pezoldt. "2H-AlGaN/GaN HEMTs on 3C-SiC(111)/Si(111) Substrates." Materials Science Forum 645-648 (April 2010): 1219–22. http://dx.doi.org/10.4028/www.scientific.net/msf.645-648.1219.

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We present the realization of high electron mobility transistors (HEMTs) based on AlGaN/GaN heterostructures grown on silicon substrates using a SiC transition layer. The growth of AlGaN/GaN heterostructures on Si (111) was performed using metalorganic chemical vapour deposition (MOCVD). The (111) SiC transition layer was realized by low pressure CVD and prevented Ga-induced meltback etching and Si-outdiffusion in the subsequent MOCVD growth. The two-dimensional electron gas (2DEG) formed at the AlGaN/GaN interface showed an electron sheet density of 1.5x1013 cm-3 and a mobility of 870 cm²/Vs proving the high structural quality of the heterostructure. Device processing was done using electron beam lithography. DC and RF characteristics were analysed and showed a peak cut-off frequency as high as 6 GHz for a 1.2 µm gate HEMT.

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Subash, T. D., T. Gnanasekaran, C. Divya, and J. Jagannathan. "Design and Simulated Characteristics of Nanosized InSb Based Heterostructure Devices." Advances in Materials Science and Engineering 2014 (2014): 1–5. http://dx.doi.org/10.1155/2014/196732.

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Indium antimonide nanoparticles were synthesized at room temperature. X-ray diffraction measurements are utilized to characterize the nanocomposites. The InSb nanoparticle has an average particle size in a range of 47 mm to 99 mm which is observed using the XRD result. The InSb is a material which is used to design the transistor. For designing purpose the simulator TCAD is used, by which the HEMT device is structured and its performance is analyzed and it is found that transistor operates as normal devices. This designed device is more valuable since a nanocomposite InSb material is used as a channel in HEMT device, thereby leading to the nanosized HEMT device. In addition, InSb has the property of high saturation velocity and mobility which results in higher performance of the device than any other materials in III-V compounds.

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Martínez, Pedro J., Enrique Maset, Pedro Martín-Holgado, Yolanda Morilla, David Gilabert, and Esteban Sanchis-Kilders. "Impact of Gamma Radiation on Dynamic RDSON Characteristics in AlGaN/GaN Power HEMTs." Materials 12, no. 17 (August 28, 2019): 2760. http://dx.doi.org/10.3390/ma12172760.

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GaN high-electron-mobility transistors (HEMTs) are promising next-generation devices in the power electronics field which can coexist with silicon semiconductors, mainly in some radiation-intensive environments, such as power space converters, where high frequencies and voltages are also needed. Its wide band gap (WBG), large breakdown electric field, and thermal stability improve actual silicon performances. However, at the moment, GaN HEMT technology suffers from some reliability issues, one of the more relevant of which is the dynamic on-state resistance (RON_dyn) regarding power switching converter applications. In this study, we focused on the drain-to-source on-resistance (RDSON) characteristics under 60Co gamma radiation of two different commercial power GaN HEMT structures. Different bias conditions were applied to both structures during irradiation and some static measurements, such as threshold voltage and leakage currents, were performed. Additionally, dynamic resistance was measured to obtain practical information about device trapping under radiation during switching mode, and how trapping in the device is affected by gamma radiation. The experimental results showed a high dependence on the HEMT structure and the bias condition applied during irradiation. Specifically, a free current collapse structure showed great stability until 3.7 Mrad(Si), unlike the other structure tested, which showed high degradation of the parameters measured. The changes were demonstrated to be due to trapping effects generated or enhanced by gamma radiation. These new results obtained about RON_dyn will help elucidate trap behaviors in switching transistors.

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Zhang, Wenli, Zhengyang Liu, Fred Lee, Shuojie She, Xiucheng Huang, and Qiang Li. "A Gallium Nitride-Based Power Module for Totem-Pole Bridgeless Power Factor Correction Rectifier." International Symposium on Microelectronics 2015, no. 1 (October 1, 2015): 000324–29. http://dx.doi.org/10.4071/isom-2015-wp11.

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The totem-pole bridgeless power factor correction (PFC) rectifier has recently gained popularity for ac-dc power conversion. The emerging gallium nitride (GaN) high-electron-mobility transistor (HEMT), having a small body diode reverse recovery effect and low switching loss, is a promising device for use in the totem-pole approach. The design, fabrication, and thermal analysis of a GaN-based full-bridge multi-chip module (MCM) for totem-pole bridgeless PFC rectifier are introduced in this work. Four cascode GaN devices using the same pair of high-voltage GaN HEMT and low-voltage silicon (Si) power metal-oxide-semiconductor field-effect transistor (MOSFET) chips, as used in the discrete TO-220 package, were integrated onto one aluminum nitride direct-bonded-copper (AlN-DBC) substrate in a newly designed MCM. This integrated power module achieves the same function as four discrete devices mounted on the circuit board. In this module design, the Si and GaN bare die were arranged in a stack-die format for each cascode device to eliminate the critical common source inductance, and thus to reduce parasitic ringing at turn-off transients. In addition, an extra capacitor was added in parallel with the drain-source terminals of the Si MOSFET in each cascode GaN device to compensate for the mismatched junction capacitance between the Si MOSFET and GaN HEMT, which could accomplish the internal zero-voltage switching of the GaN device and reduce its turn-on loss. The AlN-DBC substrate and the flip-chip format were also applied in the module design. This GaN-based MCM shows an improved heat dissipation capability based on the thermal analysis and comparison with the discrete GaN device. The totem-pole bridgeless PFC rectifier built using this integrated power module is expected to have a peak efficiency of higher than 99% with a projected power density greater than 400 W/in3.

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Kourdi, Z., B. Bouazza, A. Guen-Bouazza, and M. Khaouani. "Side Effects in a HEMT Performance with InAlN/GaN." TELKOMNIKA Indonesian Journal of Electrical Engineering 15, no. 2 (August 1, 2015): 249. http://dx.doi.org/10.11591/tijee.v15i2.1537.

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We present a simulation of a HEMT (high electron mobility transistor) structure. We extract the device characteristics through the analysis of DC, AC and high frequency regimes, as shown in this paper. This work demonstrates the optimal device with a gate length of 30 nm, and InAlN/GaN heterostructure for minimizing side effects. The simulated with Silvaco software of the HEMT devices with the materials InAlN show very good scalability in different application. We have demonstrated an excellent current density, as high as 644 mA/mm, a peak extrinsic transconductance of 710 mS/mm at VDS=2 V, and cutting frequency cutoffs of 385 GHZ, maximum frequency of 810 GHz, maximum efficiency of 23% for x-Band, maximum breakdown voltage of 365 V, and an ON/OFF current density ratio higher than 8 x 108. These values were determined through the simulation by hydrodynamics models, which makes that optimize the design is the future of this technology.

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Journal articles on the topic 'High-electron mobility (HEMT) devices'

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