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Fabrication and Physics-Based Modeling of Polar AlGaN/GaN and AlInGaN/GaN HFETs

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Fabrication and Physics-Based Modeling of Polar AlGaN/GaN and AlInGaN/GaN HFETs

Rahbardar Mojaver, Hassan (2018) Fabrication and Physics-Based Modeling of Polar AlGaN/GaN and AlInGaN/GaN HFETs. PhD thesis, Concordia University.

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Abstract

Since their advent, polar AlGaN/GaN hetero-junction field effect transistors (HFETs) have drawn a great deal of attention especially in high frequency/high power applications. However, the superb prospects of these transistors are affected by a few drawbacks such as aging/crack formation under strain, presence of high gate-leakage, and challenging realization of enhancement-mode (normally-off) devices.
Quite recently, study of quaternary AlInGaN barriers has been presented as a promising avenue for fulfilling various design demands including: lattice matching, polarization matching, and positive shifting the inherently negative threshold voltage of AlGaN/GaN HFETs. However, thus far only a limited scope of theoretical studies on AlInGaN/GaN hetero-structure characteristics has been reported. As part of this thesis, the two dimensional electron gas (2DEG) characteristics of gated metal-face wurtzite AlInGaN/GaN hetero-junctions as function of physical and compositional properties of the hetero-junction are theoretically evaluated using the variational method. According to this study, a considerable shift in the positive direction for the threshold voltage of AlInGaN/GaN HFETs can be achieved by engineering both the spontaneous and the piezoelectric polarization (using a quaternary AlInGaN barrier-layer of appropriate mole-fractions). Succeeding this study, a novel quaternary lattice-match layer structure based on employing a bilayer barrier for improving the carrier confinement in the channel of enhancement-mode AlInGaN/GaN HFETs is for the first time proposed. It is shown that while the proposed layer structure substantially improves the carrier confinement in the GaN channel layer, it also upholds the merits of employing a lattice-match barrier towards achieving an enhancement-mode operation.
One of the most important device characteristics of AlGaN/GaN HFETs which is often poorly understood is the gate-leakage current. As part of this thesis, reverse gate-leakage of AlGaN/GaN HFETs is studied over a wide range of lattice-temperatures. While unveiling an obscure path for gate leakage through the mesa sidewall, a model considering different leakage paths, including the identified sidewall leakage, is presented. It is illustrated that the sidewall path to the 2DEG is associated with the Poole-Frenkel electron emission. The novel contribution of the present analysis is that it postulates that in absence of absolute uniformity, Fowler-Nordheim (FN) tunneling takes place through only a small portion of the surface of the barrier, which boasts the highest electric field or the smallest Schottky barrier height. This consideration, allows the model to avoid unrealistic values for quantities such as effective electron mass (that has plagued many of the existing models).
Also as part of this thesis work, process recipe for microfabrication of submicron gate AlGaN/GaN HFETs using electron beam lithography was developed at McGill’s nano-tools micro-fabrication facilities. The results of DC characterization of the fabricated transistors along with the results of the DC stress test are presented.

Divisions:Concordia University > Gina Cody School of Engineering and Computer Science > Electrical and Computer Engineering
Item Type:Thesis (PhD)
Authors:Rahbardar Mojaver, Hassan
Institution:Concordia University
Degree Name:Ph. D.
Program:Electrical and Computer Engineering
Date:March 2018
Thesis Supervisor(s):Valizadeh, Pouya
Keywords:AlGaN/GaN, AlInGaN/GaN, HFETs, electron-beam lithography
ID Code:983805
Deposited By: HASSAN RAHBARDAR MOJAVER
Deposited On:05 Jun 2018 14:10
Last Modified:05 Jun 2018 14:10

References:

U. K. Mishra, P. Parikh, and Y.-F. Wu, “AlGaN/GaN HEMTs – An overview of device operation and applications,” Proc. IEEE, vol. 90, no. 6, pp. 1022–1031, Jun. 2002.
S. Keller, Y.-F. Wu, G. Parish, N. Ziang, J. J. Xu, B. P. Keller, S. P. DenBaars, and U. K. Mishra, “Gallium nitride based high power heterojunction field effect transistors: Process development and present status at UCSB,” IEEE Trans. Electron Devices, vol. 48, pp. 552–559, Mar. 2001.
S. Wienecke, B. Romanczyk, M. Guidry, H. Li, E. Ahmadi, K. Hestroffer, X. Zheng, S. Keller, and U. K. Mishra, “N-polar GaN cap MISHEMT with record power density exceeding 6.5 W/mm at 94 GHz,” IEEE Electron Device Lett., vol. 38, no. 3, pp. 359-362, Mar. 2017.
Y. Tang, K. Shinohara, D. Regan, A. Corrion, D. Brown, J. Wong, A. Schmitz, H. Fung, S. Kim, M. Micovic, “Ultrahigh-speed GaN high-electron-mobility transistors with fT/fmax of 454/444 GHz,” IEEE Electron Device Lett., vol. 36, no. 6, pp. 549-551, Jun. 2015.
P. Srivastava, J. Das, D. Visalli, M. Van Hove, P. E. Malinowski, D. Marcon, S. Lenci, K. Geens, K. Cheng, M. Leys, S. Decoutere, R. P. Mertens, and G. Borgh, “Record breakdown voltage (2200 V) of GaN DHFETs on Si With 2-μm buffer thickness by local substrate removal,” IEEE Electron Device Lett., vol. 32, no. 1, pp. 30–32, Jan. 2011.
https://gansystems.com, last access 1 March 2018.
W. Zhong, R.D. King-Smith, and D. Vanderbilt, “Giant LO-TO splitting in perovskite ferroelectrics,” Phys. Rev. Lett., vol. 72, no. 22, pp. 3618-3622, May 1994.
O. Ambacher, J. Smart, J. R. Shealy, N. G. Weimann, K. Chu, M. Murphy, W. J. Schaff, L. F. Eastman, R. Dimitrov, L. Wittmer, M. Stutzmann, W. Rieger, and J. Hilsenbeck, “Two-dimensional electron gases induced by spontaneous and piezoelectric polarization charges in N-and Ga-face AlGaN/GaN heterostructures,” J. Appl. Phys., vol. 85, no. 11, pp. 3222-3233, Mar. 1999.
S. Karmalkar, D. M. Sathaiya, and M. S. Shur, “Mechanism of the reverse gate leakage in AlGaN/GaN high electron mobility transistors,” Appl. Phys. Lett., vol. 82, no. 22, pp. 3976-3978, June 2003.
S. Sudharsanan and S. Karmalkar, “Modeling of the reverse gate leakage in AlGaN/GaN high electron mobility transistors,” J. Appl. Phys., vol. 107, no. 6, pp. 064501-1‒064501-3, Mar. 2010.
S. Turuvekere, N. Karumuri, A. A. Rahman, A. Bhattacharya, A. DasGupta, and N. DasGupta, “Gate Leakage Mechanisms in AlGaN/GaN and AlInN/GaN HEMTs: Comparison and Modeling,” IEEE Trans. Electron Dev., vol. 60, no. 10, pp. 3157-3165, Oct. 2013.
R. Jos, “Reverse Schottky gate current in AlGaN-GaN high-electron-mobility-transistors,” J. Appl. Phys., vol. 112, no. 9, pp. 094508-1‒094508-7, Nov. 2012.
H. Zhang, E. J. Miller, and E. T. Yu, “Analysis of leakage current mechanisms in Schottky contacts to GaN and Al0.25Ga0.75N/GaN grown by molecular-beam epitaxy,” J. Appl. Phys., vol. 99, no. 2, pp. 023703-1‒023703-6, Jan. 2006.
E. J. Miller, E. T. Yu, P. Waltereit, and J. S. Speck, “Analysis of reverse-bias leakage current mechanisms in GaN grown by molecular-beam epitaxy,” Appl. Phys. Lett., vol. 84, no. 4, pp. 535-537, Jan. 2004.
O. Mitrofanov and M. Manfra, “Poole-Frenkel electron emission from the traps in AlGaN/GaN transistors,” J. Appl. Phys., vol. 95, no. 11, pp. 6414-6419, June 2004.
S. Ganguly, A. Konar, Z. Hu, H. Xing, and D. Jena, “Polarization effects on gate leakage in InAlN/AlN/GaN high-electron-mobility transistors,” Appl. Phys. Lett., vol. 101, no. 25, pp. 253519-1‒253519-5, Dec. 2012.
D. Yan, H. Lu, D. Cao, D. Chen, R. Zhang, and Y. Zheng, “On the reverse gate leakage current of AlGaN/GaN high electron mobility transistors,” Appl. Phys. Lett., vol. 97, no. 15 , pp 153503-1‒153503-3, Oct. 2010.
S. Ghosh, A. Dasgupta, S. Khandelwal, S. Agnihotri, and Y. S. Chauhan “Surface-potential-based compact modeling of gate current in AlGaN/GaN HEMTs,” IEEE Trans. Electron Devices, vol. 62, no. 2, pp. 443-448, Feb. 2015.
S. Turuvekere, D. S. Rawal, A. DasGupta, and N. DasGupta. “Evidence of Fowler–Nordheim tunneling in gate leakage current of AlGaN/GaN HEMTs at room temperature,” IEEE Trans. Electron Devices, vol. 61, no. 12, pp. 4291-4294, Dec. 2014.
J. Kotani, M. Tajima, S. Kasai, and T. Hashizume, “Mechanism of surface conduction in the vicinity of Schottky gates on AlGaN/GaN heterostructures,” Appl. Phys. Lett., vol. 91, no. 9, pp. 093501-1‒093501-3, Aug. 2007.
J. Kuzmik, A. Kostopoulos, G. Konstantinidis, J.-F. Carlin, A. Georgakilas, D. Pogany, “InAlN/GaN HEMTs: A first insight into technological optimization,” IEEE Trans. Electron Devices, vol. 53, no. 3, pp. 422-426, Mar. 2006.
N. Ketteniss, L. R. Khoshroo, M. Eickelkamp, M. Heuken, H. Kalisch, R. H. Jansen, and A. Vescan, “Study on quaternary AlInGaN/GaN HFETs grown on sapphire substrates,” Semicond. Sci. Technol., vol. 25, no. 7, pp. 075013–075017, Jul. 2010.
H. R. Mojaver, F. Manouchehri, and P. Valizadeh, “Theoretical evaluation of two dimensional electron gas characteristics of quaternary AlxInyGa1-x-yN/GaN hetero-junctions,” J. Appl. Phys., vol. 119, no. 15, pp. 154502-1–154502-7, Apr. 2016.
M. Nakatsugawa, Y. Yamaguchi, and M. Muraguchi, “An L-band ultra-low-power-consumption monolithic low-noise amplifier,” IEEE trans. on microwave theory and techniques, vol. 43, no. 7, pp. 1745-1750, July 1995.
Y. Cai, Y. Zhou, K. J. Chen, and K. M. Lau, “High-performance enhancement-mode AlGaN/GaN HEMTs using fluoride-based plasma treatment,” IEEE Electron Device Letters, vol. 26, no. 7, pp. 435-437, July 2005.
R. Chu, Z. Chen, S. P. DenBaars, and U. K. Mishra, “V-Gate GaN HEMTs With Engineered Buffer for Normally Off Operation,” IEEE Electron Device Lett., vol. 29, no. 11, pp. 1184-1186, Nov. 2008.
K. Ohi and T. Hashizume, “Drain current stability and controllability of threshold voltage and subthreshold current in a multi-mesa-channel AlGaN/GaN high electron mobility transistor,” Jpn. J. Appl. Phys., vol. 48, no. 8, p. 081002-1-081002-5, Aug. 2009.
P. Valizadeh and B. AlOtaibi, “Fin- and island-isolated AlGaN/GaN HFETs”, IEEE Trans. Electron Devices, vol. 58, no. 5, pp. 1404-1407, May 2011.
H. Hahn, B. Reuters, A. Wille, N. Ketteniss, F. Benkhelifa, O. Ambacher, H. Kalisch, and A. Vescan, “First polarization-engineered compressively strained AlInGaN barrier enhancement-mode MISHFET,” Semicond. Sci. Technol., vol. 27, no. 5, pp. 055004-1-055004-6, 2012.
C. B. Soh, S. J. Chua, S. Tripathy, S. Y. Chow, D. Z. Chi, and W. Liu, “Influence of composition pulling effect on the two-dimensional electron gas formed at AlyInxGa1-x-yN∕ GaN interface,” J. Appl. Phys, vol. 98, no. 10, pp. 103704-1-103704-8, 2005.
Y. Liu, T. Egawa, and H. Jiang, “Enhancement-mode quaternary AlInGaN/GaN HEMT with non-recessed-gate on sapphire substrate,” Electronics Letters, vol. 42, no. 15, pp. 884-886, July 2006.
H. Kambayashi, Y. Satoh, Y. Niiyama, T. Kokawa, M. Iwami, T. Nomura, S. Kato, T. P. Chow, “Enhancement-mode GaN hybrid MOS-HFETs on Si substrates with over 70 A operation,” Proc. ISPSD ICs, pp. 21-24, June 2009.
B. Reuters, A. Wille, N. Ketteniss, H. Hahn, B. Holländer, M. Heuken, H. Kalisch, and A. Vescan, “Polarization-engineered enhancement mode high-electron-mobility transistors using quaternary AlInGaN barrier layers,” J. Electron. Mater., vol. 42, no. 5, pp. 826–832, 2013.
F. Manouchehri, P. Valizadeh, and M. Z. Kabir, “Determination of subband energies and 2DEG characteristics of AlxGa1−xN/GaN heterojunctions using variational method,” J. Vac. Sci. Technol. A, vol. 32, no. 2, pp. 021104-1‒021104-8, Mar. 2014.
J. Piprek, Nitride Semiconductor Devices, Wiley, Mar. 2007.
M. A. Laurent, G. Gupta, S. Wienecke, A. A. Muqtadir, S. Keller, S. P. DenBaars, and U. K. Mishra, “Extraction of net interfacial polarization charge from Al0. 54In0. 12Ga0. 34N/GaN high electron mobility transistors grown by metalorganic chemical vapor deposition,” J. Appl. Phys. vol. 116, no.18, pp. 183704-1‒183704-4, Nov. 2014.
E. Sakalauskas, B. Reuters, L. R. Khoshroo, H. Kalisch, M. Heuken, A. Vescan, M. R¨oppischer, C. Cobet, G. Gobsch, and R. Goldhahn, “Dielectric function and optical properties of quaternary AlInGaN alloys,” J. Appl. Phys., vol. 110, pp. 013102-1–013102-9, Jul. 2011.
S. H. Park, Y. T. Moon, D. S. Han, J. S. Park, and M. S. Oh, “Light emission enhancement in blue InGaAlN/InGaN quantum well structures,” Appl. Phys. Lett., vol. 99, no. 18, pp. 181101-1–181101-3, Oct. 2011.
I. Gorczyca, T. Suski, N. E. Christensen, and A. Svane, “Band gap bowing in quaternary nitride semiconducting alloys,” Appl. Phys. Lett., vol. 98, no. 24, pp. 241905-1–241905-3, Jun. 2011.
D. Jena, J. Simon, A. K. Wang, Y. Cao, K. Goodman, J. Verma, S. Ganguly, G. Li, K. Karda, V. Protasenko, C. Lian, T. Kosel, P. Fay, and H. Xing, “Polarization-engineering in group III-nitride heterostructures: New opportunities for device design,” Phys. Status Solidi A, vol. 208, no. 7, pp. 1511-1516, Jul. 2011.
G. Martin, S. Strite, A. Botchkaev, A. Rockett, and H. Morkoc, “Valence-band discontinuities of wurtzite GaN, AlN, and InN heterojunctions measured by x-ray photoemission spectroscopy,” Appl. Phys. Lett., vol. 68, no. 18, pp. 2541–2543, 1996.
H. Morkoc, Handbook of Nitride Semiconductors and Devices. New York, NY, USA: Wiley, vol. 3, 2008.
S. Satpathy, Z. S. Popovic, and W. C. Mitchel, “Theory of the composition dependence of the band offset and sheet carrier density in the GaN/AlxGa1− xN heterostructure,” J. Appl. Phys. vol. 95, no. 10, pp. 5597-5601, May 2004.
O. Ambacher, B. Foutz, J. Smart, J. R. Shealy, N. G. Weimann, K. Chu, M. Murphy, A. J. Sierakowski, W. J. Schaff, L. F. Eastman, R. Dimitrov, A. Mitchell, and M. Stutzmann, “Two dimensional electron gases induced by spontaneous and piezoelectric polarization in undoped and doped AlGaN/GaN heterostructures,” J. Appl. Phys., vol. 87, no. 1, pp. 334–344, Jan. 2000.
T. D. Veal, C. F. McConville, W. J. Schaff, “Indium Nitride and Related Alloys,” CRC Press, p. 381, 2010.
L. Rahimzadeh Khoshroo, N. Ketteniss, C. Mauder, H. Behmenburg, J. F. Woitok, I. Booker, J. Gruis, M. Heuken, A. Vescan, H. Kalisch, and R. H. Jansen, “Quaternary nitride heterostructure field effect transistors,” Phys. Status Solidi, no. 7, pp. 2001-2003, Apr. 2010.
B. Reuters, A. Wille, B. Holländer, E. Sakalauskas, N. Ketteniss, C. Mauder, R. Goldhahn, M. Heuken, H. Kalisch, and A. Vescan, “Growth studies on quaternary AlInGaN layers for HEMT application,” J. Electron. Mater. vol. 41, np. 5, pp. 905-909, May 2012.
X. Gao, M. Pan, D. Gorka, M. Oliver, M. Schuette, A. Ketterson, and P. Saunier, “Ultra‐thin barrier quaternary InAlGaN HEMTs with state of the art sheet resistance,” Phys. Status Solidi, vol. 11, no. 3-4, pp. 495-497, Feb. 2014.
http://www.nextnano.com, last accessed 1 March 2017.
H. R. Mojaver, J. L. Gosselin, and P. Valizadeh, “Use of a bilayer lattice-matched AlInGaN barrier for improving the channel carrier confinement of enhancement-mode AlInGaN/GaN hetero-structure field-effect transistors,” J. Appl. Phys., vol. 121, no. 24, pp. 244502-1–244502-6, June 2017.
N. Ketteniss, A. Askar, B. Reuters, A. Noculak, B. Holländer, H. Kalisch, A. Vescan, “Polarization-reduced quaternary InAlGaN/GaN HFET and MISHFET devices,” Semicond. Sci. Technol., vol. 27, no. 5, pp. 055012-1-055012-4, 2012.
F. Lecourt, A. Agboton, N. Ketteniss, H. Behmenburg, N. Defrance, V. Hoel, H. Kalisch, A. Vescan, M. Heuken, J. C. De Jaeger, “Power Performance at 40 GHz on Quaternary Barrier InAlGaN/GaN HEMT,” IEEE Electron Device Letters, vol. 34, no. 8, pp. 978-980, Aug. 2013.
F. Medjdoub, R. Kabouche, A. Linge, B. Grimbert, M. Zegaoui, P. Gamarra, C. Lacam, M. Tordjman, M. A. di Forte-Poisson, “High electron mobility in high-polarization sub-10 nm barrier thickness InAlGaN/GaN heterostructure,” Appl. Phys. Express, vol. 8, no. 10, pp. 101001-1-101001-4, 2015.
W. B. Lanford, T. Tanaka, Y. Otoki, and I. Adesida, “Recessed-gate enhancement-mode GaN HEMT with high threshold voltage,” Electronics Letters, vol. 41, no. 7, pp. 449-450, 31 March 2005.
S. Maroldt, C. Haupt, W. Pletschen, S. Muller, R. Quay, O. Ambacher, C. Schippel, and F. Schwierz, “Gate-recessed AlGaN/GaN based enhancement-mode high electron mobility transistors for high frequency operation,” Jpn. J. Appl. Phys., vol. 48, no. 4C, pp. 04C083-1-04C083-3, Apr. 2009.
L. Shen, S. Heikman, B. Moran, R. Coffie, N.-Q. Zhang, D. Buttari, I. P. Smorchkova, S. P. DenBaars, and U. K. Mishra “AlGaN/AlN/GaN high-power microwave HEMT,” IEEE Electron Device Letters, vol. 22, no. 10, pp. 457-459, Oct. 2001.
H. R. Mojaver and P. Valizadeh, “Reverse gate-current of AlGaN/GaN HFETs: Evidence of leakage at mesa sidewalls,” IEEE Trans. Electron Devices, vol. 63, no. 4, pp. 1444-1449, Apr. 2016.
A. Loghmany and P. Valizadeh, “Alternative isolation-feature geometries and polarization-engineering of polar AlGaN/GaN HFETs,” Solid-State Electron., vol. 103, pp. 162-166, Aug. 2014.
C. Xu, J. Wang, H. Chen, F. Xu, Z. Dong, Y. Hao, and C. P. Wen. “The leakage current of the Schottky contact on the mesa edge of AlGaN/GaN heterostructure,” Electron Dev. Lett., vol. 28, no. 11, pp. 942-944, Nov. 2007.
W. L. Chang, H. J. Pan, W. C. Wang, K. B. Thei, W. S. Lour, and W. C. Liu., “Influences of the mesa-sidewall effect on Ga0.51In0.49P/In0.15Ga0.85As pseudomorphic transistors,” Semicond. Sci. Technol., vol. 14, no.10, pp. 887-891, July 1999.
S. R. Bahl and J. A. del Alamo, “Elimination of Mesa-Sidewall Gate Leakage in InAlAs /InGaAs Heterostructures by Selective Sidewall Recessing,” IEEE Trans. Electron Dev., vol. 13, no. 4, pp. 195-197, Apr. 1992.
A. S. Brown, C. S. Chou, M. J. Delaney, C. E. Hooper, J. F. Jensen, L. E. Larson, U. K. Mishra, L. D. Nguyen, and M. S. Thompson. “Low-temperature buffer AlInAs/GaInAs on InP HEMT technology for ultra-high-speed integrated circuits,” proceedings of GaAs IC. Symp., pp. 143-146, 1989.
Y. S. Lin, Y. W. Lain, and S. S. Hsu, “AlGaN/GaN HEMTs with low leakage current and high on/off current ratio,” Electron Dev. Lett., vol. 31, no. 2, pp. 102-104, Feb. 2010.
J. Kováč, A. Šatka, A. Chvála, D. Donoval, P. Kordoš, and S. Delage, “Gate leakage current in GaN-based mesa-and planar-type heterostructure field-effect transistors,” Microelectronics Reliability, vol. 52, no. 7, pp. 1323-1327, Feb. 2012.
P. Liu, C. Xie, F. Zhang, J. Chen, and D. Chen, “Elimination of gate leakage in GaN FETs by placing oxide spacers on the mesa sidewalls,” Electron Dev. Lett., vol. 34, no. 10, pp. 1232-1234, Oct 2013.
Y. H. Chen, K. Zhang, M. Y. Cao, S. L. Zhao, J. C. Zhang, X. H. Ma, and Y. Hao, “Study of surface leakage current of AlGaN/GaN high electron mobility transistors,” Appl. Phys. Lett., vol. 104, no. 15, pp. 153509-1‒153509-4, Apr. 2014.
M. Lenzlinger and E. H. Snow, “Fowler–Nordheim tunneling into thermally grown SiO2,” J. Appl. Phys., vol. 40, no. 1, pp. 278–283, Jan. 1969.
L. Xia, A. Hanson, T. Boles, and D. Jin, “On reverse gate leakage current of GaN high electron mobility transistors on silicon substrate,” Appl. Phys. Lett., vol. 102, no.11, pp. 113510-1–113510-4, Mar. 2013.
A. Fontsere, A. Pérez-Tomás, M. Placidi, J. Llobet, N. Baron, S. Chenot, Y. Cordier, J. C. Moreno, M. R. Jennings, P. M. Gammon, C. A. Fisher, V. Iglesias, M. Porti, A. Bayerl, M. Lanza, and M. Nafria, “Nanoscale investigation of AlGaN/GaN-on-Si high electron mobility transistors,” Nanotechnology, vol. 23, no.19, pp.395204-1–395204-8, Sep. 2012.
Y.-N. Xu and W. Y. Ching, “Electronic, optical, and structural properties of some wurtzite crystals,” Phys. Rev. B, vol. 48, no. 7, pp. 4335–4351, Aug. 1993.
D. Donoval, A. Chvála, R. Šramatý, J. Kováè, J.-F. Carlin, N. Grandjean, G. Pozzovivo, J. Kuzmík, D. Pogany, G. Strasser, and P. Kordoš, “Current transport and barrier height evaluation in Ni/InAlN/GaN Schottky diodes,” Appl. Phys. Lett., vol. 96, no. 22, pp. 223501-1–223501-3, May 2010.
T. D. Veal, C. F. McConville, and W. J. Schaff, Indium Nitride and Related Alloys. New York, NY, USA: CRC Press, 2010, p. 111.
A. Koukitu and H. Seki, “Unstable region of solid composition in ternary nitride alloys grown by metalorganic vapor phase epitaxy,” Japanese J. Appl. Phys., vol. 35, no. 12B, pp. L1638–L1640, Dec. 1996.
T. Hashizume, J. Kotani, and H. Hasegawa, “Leakage mechanism in GaN and AlGaN Schottky interfaces,” Appl. Phys. Lett., vol. 84, no. 24, pp. 4884–4886, Jun. 2004.
Y. P. Varshni, “Temperature dependence of the energy gap in semiconductors,” Physica, vol. 34, no. 1, pp. 149–154, 1967.
R. S. Muller, T. I. Kamins, and M. Chan, Device Electronics for Integrated Circuits. New York, NY, USA: Wiley, 2003, p. 151.
N. Nepal, J. Li, M. L. Nakarmi, J. Y. Lin, and H. X. Jiang, “Temperature and compositional dependence of the energy band gap of AlGaN alloys,” Appl. Phys. Lett., vol. 87, no. 24, pp. 242104-1-242104-3, Dec. 2005.
K. B. Nam, J. Li, J. Y. Lin, and H. X. Jiang, “Optical properties of AlN and GaN in elevated temperatures,” Appl. Phys. Lett., vol. 85, no. 16, pp. 3489-3491, Oct. 2004.
L. Lymperakis, P. Weidlich, H. Eisele, M. Schnedler, J. Nys, B. Grandidier, D. Stiévenard, R. Dunin-Borkowski, J. Neugebauer, and P. Ebert, “Hidden surface states at non-polar GaN (101 ̅0) facets: Intrinsic pinning of nanowires,” Appl. Phys. Lett., vol. 103, no.15, pp. 152101-1–152101-4, Oct. 2013.
J. Frenkel, “On pre-breakdown phenomena in insulators and electronic semi-conductors,” Phys. Rev., vol. 54, p. 647, Oct. 1938.
P. M. Dentinger, W. M. Clift, and S. H. Goods, “Removal of SU-8 photoresist for thick film applications,” J. Microelec. Eng., vol. 61–62, pp. 993–1000, 2002.
A. Loghmany, “Design, Microfabrication, and Characterization of Polar III-Nitride HFETs,” Ph.D. dissertation, Concordia University, 2016.
J. Record, “Fabrication, Characterization, and Simulation of Gallium-Nitride Heterojunction Field-Effect Transistors,” M.A.Sc. thesis, Concordia University, 2016
Lihua An, Yuankai Zheng, Kebin Li, Ping Luo, Yihong Wu, “Nanometer metal line fabrication using a ZEP520/50 K PMMA bilayer resist bye-beam lithography”, J. Vac. Sci. Technol. B, vol. 23, no. 4, pp. 1603-1606, Jul. 2005.
B. Cord, C. Dames, K. K. Berggren, J. Aumentado, “Robust shadow-mask evaporation via lithographically controlled undercut,” J. Vac. Sci. Technol. B, vol. 24, no.6, pp. 3139-3143, Nov. 2006.
H. Yang, A. Jin, Q. Luo, J. Li, C. Gu, Z. Cui, “Electron beam lithography of HSQ/PMMA bilayer resists for negative tone lift-off process,” Microelectronic Engineering, vol. 85, no.5, pp. 814-817, May 2008.
M. F. Romero, A. Jimenez, C. Palacio, D. Diaz, and E. Munoz, “Electrical and microstructural characteristics of Ohmic contacts formation on AlGaN/GaN HEMT,” 2009 Spanish Conference on Electron Devices, pp. 258–261, Feb. 2009.
P. Valizadeh and D. Pavlidis, “Investigation of the Impact of Al Mole-Fraction on the Consequences of RF Stress on AlxGa1-x/GaN MODFETs”, IEEE Transactions on Electron Devices, vol. 5, no. 3, pp. 555-563, Sep. 2005.
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