GaN, with a high electron saturation velocity, a large critical electrical field, good thermal conductivity, strong polarization fields, and epi-layer grown on Si, has been intensively investigated for applications in power RF electronics and high-temperature applications. In addition, the aggressive scaling of CMOS devices dramatically increases the horizontal electric field of the channel region. At this high electric field, GaN may outperform III-V and Si in high saturation velocity and resulted in better cutoff frequency and drain current. Therefore, GaN is now also being considered as a channel candidate for the next generation CMOS devices.
In this dissertation, high-performance accumulation-type and inversion-type GaN MOSFETs have been demonstrated by using atomic-layer-deposited (ALD) Al2O3 and HfO2, and molecular-beam-epitaxy grown (MBE) Ga2O3(Gd2O3) as gate dielectrics. For the first time, fabrication of inversion-type GaN MOSFETs were successfully achieved with ALD high k gate dielectrics which showed a normally-off characteristic with large threshold voltage (Vth > 2.5 V), a very low off-state drain current (Ioff) of 4×10-13 A/um as well as a high Ion/Ioff ratio. The device performances are markedly improved compared to the previous results of inversion-type GaN MOSFETs with high k gate dielectrics.
In addition, the accumulation-type GaN MOSFETs also exhibited outstanding device performances as compared to those of previously reported GaN MOSFETs. For example, the 4 um gate-length device exhibited the record high drain current density (Id) of 300 mA/mm at gate voltage of 8 V and drain voltage of 20 V. Compared to the state-of-the-art GaN HEMTs, the simply-designed GaN MOSFETs provide low gate leakage currents, negligible current collapses, and comparable drain currents, with the devices being normalized to the same gate lengths.
The crucial interfacial quality and microstructure between these high-k thin films and GaN were systematically investigated by using x-ray reflectivity (XRR), transmission electron microscope (TEM), x-ray photoelectron spectroscopy (XPS), and electrical characterizations. The electrical characterizations including capacitance-voltage (C-V) and gate leakage current-voltage (I-V) measurements were performed on the GaN MOS capacitors. The sharp interface with roughness < 0.5 nm, low interfacial density of states (Dit) in the range of 5×1011 eV-1cm-2, and a large conduction-band offset (ΔEc) of 1.85±0.1 eV at Al2O3/GaN interface have been extracted. These superior material and electrical properties, and the distinct merits of wide bandgap GaN contributed to the remarkable device performances of the GaN MOSFETs. The results clearly establish the potential of using these high-quality high-□ gate dielectric/GaN heterostructures for advanced CMOS, power RF electronics, and high-temperature application.

[1] F. Ren, M. Hong, S. N. G. Chu, M. A. Marcus, M. J. Schurman, A. Baca, S. J. Pearton, and C. R. Abernathy, “Effect of temperature on Ga2O3(Gd2O3)/GaN metal-oxide-semiconductor field-effect transistors,” Appl. Phys. Lett., 73, 3893 (1998).
[2] J. W. Johnson, B. Luo, F. Ren, B. P. Gila, W. Krishnamoorthy, C. R. Abernathy, S. J. Pearton, J. I. Chyi, T. E. Nee, C. M. Lee, C. C. Chuo, “Gd2O3/GaN metal-oxide-semiconductor field-effect transistor,” Appl. Phys. Lett., 77, 3230 (2000).
[3] Y. Q. Wu, P. D. Ye, G. D. Wilk, and B. Yang, “GaN metal-oxide-semiconductor field-effect-transistor with atomic layer deposited Al2O3 as gate dielectric,” Mater. Sci. Eng. B, 135, 282 (2006).
[4] Y. Irokawa, Y. Nakano, M. Ishiko, T. Kachi, J. Kim, F. Ren, B. P. Gila, A. H. Onstine, C. R. Abernathy, S. J. Pearton, C. C. Pan, G. T. Chen, and J. I. Chyi, “MgO/p-GaN enhancement mode metal-oxide semiconductor field-effect transistors,” Appl. Phys. Lett., 84, 2919 (2004).
[5].W. Huang, T. Khan, and T. P. Chow, “Enhancement-Mode n-Channel GaN MOSFETs on p and n-GaN/Sapphire Substrates,” IEEE Electron Device Lett, 27, 796 (2006).
[6] H. B. Lee, H. I. Cho, H. S. An, Y. H. Bae, M. B. Lee, J. H. Lee, and S. H. Hahm, “A Normally Off GaN n-MOSFET With Schottky-Barrier Source and Drain on a Si-Auto-Doped p-GaN/Si,” IEEE Electron Device Lett., 27, 81 (2006).
[7] Y. N. Saripalli, L. Pei, T. Biggerstaff, S. Ramachandran, G. J. Duscher, M. A. L. Johnson, C. Zeng, K. Dandu, Y. Jin, and D. W. Barlage, “Transmission electron microscopy studies of regrown GaN Ohmic contacts on patterned substrates for metal oxide semiconductor field effect transistor applications,” Appl. Phys. Lett., 90, 204106 (2007).
[8] Y. C. Chang, W. H. Chang, H. C. Chiu, L. T. Tung, C. H. Lee, K. H. Shiu, M. Hong, J. Kwo, J. M. Hong, and C. C. Tsai, “Inversion-channel GaN metal- oxide-semiconductor field-effect-transistor with atomic-layer-deposited Al2O3 as gate dielectric,” Appl. Phys. Lett., 93, 053504 (2008).
[9] W. Huang, T. P. Chow, Y. Niiyama, T. Nomura, and S. Yoshida, “Experimental Demonstration of Novel High-Voltage Epilayer RESURF GaN MOSFET,” IEEE Electron Device Lett., 30, 1018 (2009).
[10] Y. C. Chang, W. H. Chang, Y. H. Chang, J. Kwo, Y. S. Lin, S. H. Hsu, J. M. Hong, C. C. Tsai, and M. Hong, “Drain current enhancement and negligible current collapse in GaN MOSFETs with atomic-layer-deposited HfO2 as a gate dielectric,” Microelec. Eng., 87, 2042 (2010).
[11] K. W. Lee, D. W. Chou, H. R. Wu, J. J. Huang, Y. H. Wang, M. P. Houng, S. J. Chang, and Y. K. Su, “GaN MOSFET with liquid phase deposited oxide gate,” Electron. Lett., 38, 829 (2002).
[12] A. Pérez-Tomás, M. Placidi, N. Baron, S. Chenot, Y. Cordier, J. C. Moreno, A. Constant, P. Godignon, and J. Millán, “GaN transistor characteristics at elevated temperatures,” J. Appl. Phys., 106, 074519 (2009).
[13] A. Pérez-Tomás, M. Placidi, X. Perpiñà, A. Constant, P. Godignon, X. Jordà, P. Brosselard, and J. Millán, ”GaN metal-oxide-semiconductor field-effect transistor inversion channel mobility modeling,” J. Appl. Phys., 105, 114510 (2009).
[14] U. V. Bhapkar and M. S. Shur, “Monte Carlo calculation of velocity-field characteristics of wurtzite GaN,” J. Appl. Phys., 82, 1649 (1997).
[15] L. Ardaravičius, M. Ramonas, J. Liberis, O. Kiprijanovič, A. Matulionis, J. Xie, M. Wu, J. H. Leach, and H. Morkoç, “Electron drift velocity in lattice-matched AlInN/AlN/GaN channel at high electric fields,” J. Appl. Phys., 106, 073708 (2009).
[16] R. Juza and H. Hahn, “Crystal structures of Cu3N, GaN and InN - metallic amides and metallic nitrides V Announcement”, Anorg. Allegem. Chem. 239, 282 (1938); and “ Examinations on the nitrides of cadmium, gallium, indium and germanium - Metal amides and metal nitrides VIII Announcement,” Anorg. Allegem. Chem., 244, 133 (1940).
[17] H. P. Maruska and J. J. Tietjen, “Preparation and properties of vapor-deposited single-crystalline GaN,” Appl. Phys. Lett., 15, 327 (1969).
[18] J. I. Pankove, E. A. Miller, and J. E. Berkeyheister, “GaN blue light-emitting diodes, ” J. Lumin., 5, 84 (1972).
[19] H. P. Maruska, W. C. Rhines, and D. A. Stevendson, “Preparation of Mg-doped GaN diodes exhibiting violet electroluminescence,” Mater. Res. Bull., 7, 777 (1972).
[20] W. Seifert, R. Franzheld, E. Buttler, H. Sobotta, and V. Reide, “On the origin of free carriers in high-conducting n-GaN,” Cryst. Res. Technol., 18, 383 (1983).
[21] H. Amano, N. Sawaki, I. Akasaki, and Y. Toyoda, “Metalorganic vapor phase epitaxial growth of a high quality GaN film using an AlN buffer layer,” Appl. Phys. Lett., 48, 353 (1986).
[22] H. Amano, M. Kito, K. Hiramatsu, and I. Akasaki, “P-type conduction in Mg-doped GaN treated with low-energy electron beam irradiation,” Jpn. J. Appl. Phys., 28, 2112 (1989).
[23] S. Nakamura, N. Iwasa, M. Senoh, and T. Mukai, “Hole compensation mechanism of p-type GaN films,” Jpn. J. Appl. Phys., 31, 1258 (1992).
[24] S. Nakamura, T. Mukai, and M. Senoh, “P-GaN/n-InGaN/n-GaN double- heterostructure blue-light-emitting diodes,” Jpn. J. Appl. Phys., 32, 8 (1993).
[25] S. Nakamura, T. Mukai, and M. Senoh, “Candela-class high-brightness InGaN/AlGaN double-heterostructure blue-light-emitting diodes,” Appl. Phys. Lett., 64, 1687 (1994).
[26] S. Nakamura, M. Senoh, S. Nagahama, N. Iwasa, T. Matsushita, T. Mukai, “Blue InGaN-based laser diodes with an emission wavelength of 450 nm,” Appl. Phys. Lett., 76, 22 (2000).
[27] M. Asif Khan, J. M. Van Hove, J. N. Kuznia, and D. T. Olson, “High electron mobility GaN/AlxGa1-xN hetrostructures grown by low-pressure metalorganic chemical vapor deposition,” Appl. Phys. Lett., 58, 2408 (1991).
[28] M. Asif Khan, J. N. Kuznia, A. R. Bhattarai, and D. T. Olson, “Metal semiconductor field effect transistor based on single crystal GaN,” Appl. Phys. Lett., 62, 1786 (1993).
[29] M. Asif Khan, J. N. Kuznia, D. T. Olson, W. J. Schaff , J. W. Burm, and M. S. Shur, “Microwave performance of a 0.25 mu-m gate AlGaN/GaN heterostructure field effect transistor,” Appl. Phys. Lett., 65 1121 (1994)
[30] Y.-F. Wu B. P. Keller, S. Keller, D. Kapolnek, P. Kozodoy, S. P. Denbaars, and U. K. Mishra, “Very high breakdown voltage and large transconductance realized on GaN heterojunction field effect transistors”, Appl. Phys. Lett. 69, 1438 (1996).
[31] J. Burm, W. J. Schaff, L. F. Eastman, H. Amano, and I. Akasaki, “75 Å GaN channel modulation doped field effect transistors,” Appl. Phys. Lett., 68, 2849 (1996).
[32] S. T. Sheppard, K. Doverspike, W. L. Pribble, S. T. Allen, J. W. Palmour, L. T. Kehias, and T. J. Jenkins, “High-power microwave GaN/AlGaN HEMT’s on semi-insulating Silicon Carbide substrates,” IEEE Electron Device Lett., 20, 161 (1999).
[33] D. Ducatteau, A. Minko, V. Hoël, E. Morvan, E. Delos, B. Grimbert, H. Lahreche, P. Bove, C. Gaquière, J. C. De Jaeger, and S. Delage, “Output Power Density of 5.1/mm at 18 GHz With an AlGaN/GaN HEMT on Si Substrate,” IEEE Electron Device Lett., 27, 7 (2006).
[34] J. W. Chung, E. L. Piner, and T. Palacios, “N-Face GaN/AlGaN HEMTs fabricated throughlayer transfer technology,” IEEE Electron Device Lett., 30, 113 (2009).
[35] C. Y. Chang, S. J. Pearton, C. F. Lo, F. Ren, I. I. Kravchenko, A. M. Dabiran, A. M. Wowchak, B. Cui, and P. P. Chow, “Development of enhancement mode AlN/GaN high electron mobility transistors,” Appl. Phys. Lett., 94, 263505 (2009).
[36] N. Nidhi, S. Dasgupta, D. F. Brown, S. Keller, J. S. Speck, and U. K. Mishra, “N-polar GaN-based highly scaled self-aligned MIS-HEMTs with state-of-the-art fT.LG product of 16.8 GHz-μm,” Tech. Dig. IEEE IEDM, p. 955, 2009.
[37] P. D. Ye, B. Yang, K. K. Ng, J. Bude, G. D. Wilk, S. Halder, and J. C. M. Hwang, “GaN MOS-HEMT using atomic layer deposition Al2O3 as gate dielectric and surface passivation,” Appl. Phys. Lett., 86, 063501 (2005).
[38] M. Higashiwaki, T. Matsui, and T. Mimura, “AlGaN/GaN MIS-HFETs with fT of 163 GHz usingCat-CVD SiN gate-insulating and passivation layers,” IEEE Electron Device Lett., 27, 16 (2006).
[39] J. X. Shi, L. F. Eastman, X. B. Xin, and M. Pophristic, “High performance AlGaN/GaN power switch with HfO2 insulation,” Appl. Phys. Lett., 95, 042103 (2009).
[40] H. Kambayashi, Y. Satoh, S. Ootomo, T. Kokawa, T. Nomura, S. Kato, T. S. Pawl Chow, “Over 100 A operation normally-off AlGaN/GaN hybrid MOS-HFET on Si substrate with high-breakdown voltage,” Solid-State Electron., 54, 660 (2010).
[41] Z. H. Liu, G. I. Ng, S. Arulkumaran, Y. K. T. Maung, K. L. Teo, S. C. Foo, V. Sahmuganathan, “Improved two-dimensional electron gas transport characteristics in AlGaN/GaN metal-insulator-semiconductor high electron mobility transistor with atomic layer-deposited Al2O3 as gate insulator,” Appl. Phys. Lett., 95, 223501 (2009).
[42] S. Wolf and R. N. Tauber, Silicon Processing for the VLSI Era Volume 1-Process Technology, 2nd ed. Sunset Beach, CA: Lattice Press, 2001.
[43] S. Porowski, “Growth and properties of single crystalline GaN substrates and homoepitaxial layers,” Proc. 5th Int. Conf. Nitride Semiconductors, p. 70, 2003.
[44] J. Karpinski, S. Porowski, “High-pressure thermodynamics of GaN,” J. Crystal Growth, 66, 11 (1984).
[45] S. Porowski, I. Grzegory, S. Krukowski, “Thermodynamics and growth of GaN single crystals under pressure,” Mater. Res. Soc. Symp. Proc., 499, 349 (1998).
[46] S. W. King, J. P. Barnak, M. D. Bremser, K. M. Tracy, C. Ronning, R. F. Davis, R. J. Nemanich, “Cleaning of AlN and GaN surfaces,” J. Appl. Phys., 84, 5248 (1998).
[47] M.K. Kelly, O. Ambacher, B. Dahlheimer, G. Groos, R. Dimitrov, H. Angerer, M. Stutzmann, “Optical patterning of GaN films,” Appl. Phys. Lett., 69, 1749 (1996).
[48] B. Molnar, A.E. Wickenden, M.V. Rao, “Si Implantation and annealing of GaN for n-type layer formation,” Mater. Res. Soc. Symp. Proc., 423, 183 (1996).
[49] T. Suski, J. Jun, M. Leszczynski, H. Teisseyre, I. Grzegory, S. Porowski, G. Dollinger, K. Saarinen, T. Laine, J. Nissila, W. Burkhard, W. Kriegseis, and B. K. Meyer, “High pressure fabrication and processing of GaN:Mg,” Mater. Sci. Eng. B, 59, 1 (1999).
[50] W. H. Chang, C. H. Lee, Y. C. Chang, P. Chang, M. L. Huang, Y. J. Lee, C. H. Hsu, J. M. Hong, C. C. Tsai, J. R. Kwo, and M. W. Hong, “Nanometer-Thick Single-Crystal Hexagonal Gd2O3 on GaN for Advanced Complementary Metal-Oxide-Semiconductor Technology,” Adv. Mater., 21, 4970 (2009).
[51] W. H. Chang, C. H. Lee, P. Chang, Y. C. Chang, Y. J. Lee, J. Kwo, C. C. Tsai, J. M. Hong, C. H. Hsu, and M. Hong, “High kappa dielectric single-crystal monoclinic Gd2O3 on GaN with excellent thermal, structural, and electrical properties,” J. Cryst. Growth, 311, 2183 (2009).
[52] M. Hong, J. Kwo, S. N. G. Chu, J. P. Mannaerts, A. R. Kortan, H. M. Ng, A. Y. Cho, K. A. Anselm, C. M. Lee, and J. I. Chyi, “Single-crystal GaN/Gd2O3/GaN heterostructure,” J. Vac. Sci. Technol. B, 20, 1274 (2002).
[53] M. Zinkevich, “Calorimetric study and thermodynamic assessment of the SrO-Ga2O3 system,” Prog. Mater. Sci., 98, 594 (2007).
[54] C.-H. Jan, M. Agostinelli, M. Buehler, Z.-P. Chen, S.-J. Choi, G. Curello, H. Deshpande, S. Gannavaram, W. Hafez, U. Jalan, M. Kang, P. Kolar, K. Komeyli, B. Landau, A. Lake, N. Lazo, S.-H. Lee, T. Leo, J. Lin, N. Lindert, S. Ma, L. McGill, C. Meining, A. Paliwal, J. Park, K. Phoa, I. Post, N. Pradhan, M. Prince, A. Rahman, J. Rizk, L. Rockford, G. Sacks, A. Schmitz, H. Tashiro, C. Tsai, P. Vandervoorn, J. Xu, L. Yang, J.-Y. Yeh, J. Yip, K. Zhang, Y. Zhang, and P. Bai, Tech. Dig. IEEE IEDM, p. 647, 2009.
[55] J. Robertson and P.W. Peacock, in: M. Houssa (Ed.), High-□ Gate Dielectrics, IOP, London, 2003.
[56] T.S. Lay, M. Hong, J. Kwo, J.P. Mannaerts, W.H. Hung, D.J. Huang, “Energy-band parameters at the GaAs- and GaN-Ga2O3(Gd2O3) interfaces,” Solid-State Electron., 45, 1679 (2001).
[57] M. Hong, K. A. Anselm, J. Kwo, H. M. Ng, J. N. Baillargeon, A. R. Kortan, J. P. Mannaerts, A. Y. Cho, C. M. Lee, J. I. Chyi, and T. S. Lay, ” Properties of Ga2O3(Gd2O3)/GaN metal-insulator- semiconductor diodes,” J. Vac. Sci. Technol. B, 18, 1453 (2000).
[58] J. Kim, R. Mehandru, B. Luo, F. Ren, B. P. Gila, A. H. Onstine, C. R. Abernathy, S. J. Pearton, and Y. Irokawa, “Inversion behavior in Sc2O3/GaN gated diodes,” Appl. Phys. Lett., 81, 373 (2002).
[59] T. Tanaka, A. Watanabe, H. Amano, Y. Kobayashi, I. Akasaki, S. Yamazaki, M. Koike, “p‐type conduction in Mg‐doped GaN and Al0.08Ga0.92N grown by metalorganic vapor phase epitaxy,” Appl. Phys. Lett., 65, 593 (1994).
[60] B. J. Baliga, “Trends in power semiconductor devices,” IEEE Trans. Electron Devices, 43, 1717 (1996).
[61] B. J. Baliga, “Semiconductors for high voltage vertical channel field effect transistors,” J. Appl Phys., 53, 1759 (1982).
[62] E. O. Johnson, “Physical limitations on frequency and power parameters of transistors,” RCA Rev., 163 (1965).
[63] R. W. Keyes, “Figure of merit for semiconductors for high-speed switches,” Proc. IEEE, 225 (1972).
[64] B. J. Baliga, “Power semiconductor device figure of merit for high-frequency applications,” IEEE Electron Device Lett., 10, 455 (1989).
[65] http://www.intel.com/technology/
[66] Y. Xuan, Y. Q. Wu, and P. D. Ye, “High-performance inversion-type enhancement-mode InGaAs MOSFET with maximum drain current exceeding 1 A/mm,” IEEE Electron Device Lett., 29, 294 (2008).
[67] D. Lin, G. Brammertz, S. Sioncke, C. Fleischmann, A. Delabie, K. Martens , H. Bender, T. Conard, W. H. Tseng , J. C. Lin, W. E. Wang, K. Temst, A, Vatomme, J. Mitard, M. Caymax, M. Meuris, M. Heyns, and T. Hoffmann, Tech. Dig. IEEE IEDM, p. 327, 2009.
[68] J. P. de Souza, E. Kiewra, Y. Sun, Callegari, K. Sadana, G. Shahidi, D. J. Webb, J. Fompeyrine, R. Germann, C. Rossel, and C. Marchiori, “Inversion mode n-channel GaAs field effect transistor with high-□/metal gate,” Appl. Phys. Lett., 92, 153508 (2008).
[69] P. D. Ye, G. D. Wilk, B. Yang, J. Kwo, S. N. G. Chu, S. Nakahara, H.-J. L. Gossmann, J. P. Mannaerts, M. Hong, K. K. Ng, and J. Bude, “GaAs metal-oxide-semiconductor field-effect transistor with nanometer-thin dielectric grown by atomic layer deposition,” Appl. Phys. Lett., 83, 180 (2003).
[70] M. L. Huang, Y. C. Chang, C. H. Chang, Y. J. Lee, P. Chang, J.Kwo, T. B. Wu and M. Hong, “Surface passivation of III-V compound semiconductors using atomic-layer-deposition-grown Al2O3,” Appl. Phys. Lett., 87, 252104 (2005).
[71] Y. C. Chang, M. L. Huang, K. Y. Lee, Y. J. Lee, T. D. Lin, M. Hong, J. Kwo, T.S. Lay, C. C. Liao, and K. Y. Cheng, ”Atomic-layer-deposited HfO2 on In0.53Ga0.47As: Passivation and energy-band parameters,” Appl. Phys. Lett., 92, 072901 (2008).
[72] M. L. Huang, Y. C. Chang, Y. H. Chang, T. D. Lin, J. Kwo, M. Hong M, “Energy-band parameters of atomic layer deposited Al2O3 and HfO2 on InxGa1-xAs,” Appl. Phys. Lett., 94, 052106 (2009).
[73] K. Y. Lee, Y. J. Lee, P. Chang, M. L. Huang, Y. C. Chang, M. Hong, and J. Kwo, “Achieving one nanometer capacitive effective thickness in atomic layer deposited HfO2 on In0.53Ga0.47As,” Appl. Phys. Lett., 92, 252908 (2008).
[74] C. H. Chang, Y. K. Chiou, Y. C. Chang, K. Y. Lee, T. D. Lin, T. B. Wu, M. Hong, and J. Kwo, “Interfacial self-cleaning in atomic layer deposition of HfO2 gate dielectric on In0.15Ga0.85As,” Appl. Phys. Lett., 89, 242911 (2006).
[75] E. H. Nicollian and J. R. Brews, MOS Physics and Technology (Wiley, New York, 1981).
[76] K.Y. Lee, W.C. Lee, M.L. Huang, C.H. Chang, Y.J. Lee, Y.K. Chiu, T.B. Wu, M. Hong, and R. Kwo, “A novel approach of using a MBE template for ALD growth of high-kappa dielectrics,” J. Cryst. Growth, 301-302, 378 (2007).
[77] C. O. Chui, H. Kim, D. Chi, P. C. McIntyre, K. C. Saraswat, “Nanoscale germanium MOS dielectrics - Part II: High-kappa gate dielectrics,” IEEE Trans. Electron Devices, 53, 1509 (2006).
[78] D. Hoogeland, K. B. Jinesh, F. Roozeboom, W. F. A. Besling, M. C. M. van de Sanden, and W. M. M. Kessels, “Plasma-assisted atomic layer deposition of TiN/Al2O3 stacks for metal-oxide-semiconductor capacitor applications,” Appl. Phys. Lett., 106, 114107 (2009)
[79] C. Liu, E. F. Chor, L. S. Tan, and Y. Dong, “Structural and electrical characterizations of the pulsed-laser-deposition-grown Sc2O3/GaN heterostructure,” Appl. Phys. Lett., 88, 222113 (2006).
[80] C. T. Lee, H. Y. Lee, and H. W. Chen,” GaN MOS device using SiO2-Ga2O3 insulator grown by photoelectrochemical oxidation method,” IEEE Electron Device Lett., 24, 54 (2003).
[81] S.J.Hong, P.Chapman, P.T. Krein, and K.Kim, “selective-area growth and fabrication of recessed-gate GaN MESFET using plasma-assisted molecular beam epitaxy,” Phys. S tat. Sol., 203, 1872 (2006).
[82] C. Lee, W. Lu, E. Piner, I. Adesida, “DC and microwave performance of recessed-gate GaNMESFETs using ICP-RIE,” Solid-State Electron., 46, 743 (2002).
[83] J. S. Jang, I. S. Chang, H. K. Kim, T.Y. Seong, S. H. Lee, and S. J. Park, “Low-resistance Pt/Ni/Au ohmic contacts to p-type GaN,” Appl. Phys. Lett., 74, 70 (1999).
[84] S. J. Pearton, J. C. Zolper, R. J. Shul, F. Ren, “GaN: Processing, defects, and devices,” J. Appl. Phys., 86, 1 (1999).
[85] J. C. Zolper, M. H. Crawford, J. S. Williams, H. H. Tan, R. A. Stall, “High dose Si- and Mg-implantation in GaN: Electrical and structural analysis,” Nucl. Instr. and Meth. in Phys. Res. B, 127/128, 467 (1997).
[86] C. Ronning, E.P. Carlson, R.F. Davis, “Ion implantation into gallium nitride,” Phys. Rep., 351, 349 (2001).
[87] A. G. Sabnis and J. T. Clemens, “Characterization of the electron mobility in the inverted (100) Si surface,” Tech. Dig. IEEE IEDM, p.18, 1979.
[88] Y. Yamashita, A. Endoh, K. Shinohara, K. Hikosaka, T. Matsui, S. Hiyamizu, and T. Mimura, “Pseudomorphic In0.52Al0.48As/In0.7Ga0.3As HEMTs With an Ultrahigh fT of 562 GHz,” IEEE Electron Device Lett., 23, 573 (2002)
[89] S. Paul, J. B. Roy, and P. K. Basu, “Empirical expressions for the alloy composition and temperature dependence of the band gap and intrinsic carrier density in GaxIn1-xAs,” J. Appl. Phys., 69, 827 (1991).
[90] R. K. Ahrenkiel, R. Ellingson, S. Johnston, and M. Wanlass, “Recombination lifetime of In0.53Ga0.47As as a function of doping density,” Appl. Phys. Lett., 72, 3470 (1998).
[91] M. Hong, J. Kwo, P. J. Tsai , Y. C. Chang, M. L. Huang , C. P. Chen, and T. D. Lin, “III-V MOSFET’s with High □ Dielectrics,” Jpn. J. Appl. Phys., 46, 3167 (2007).
[92] C. W. Wilmsen, Ed., Physics and Chemistry of III-V Compound Semiconductor Interfaces (Plenum, New York, 1985).
[93] M. Hong, J. P. Mannaerts, J. E. Bower, J. Kwo, M. Passlack, W.-Y. Hwang, and L. W. Tu, “Novel Ga2O3(Gd2O3) passivation techniques to produce low Dit oxide-GaAs interfaces,” J. Cryst. Growth 175/176, 422 (1997).
[94] M. Hong, J. Kwo, A. R. Kortan, J. P. Mannaerts, and A. M. Sergent, “Epitaxial cubic gadolinium oxide as a dielectric for gallium arsenide passivation,” Science 283, 1897 (1999).
[95] W. E. Spicer, P. W. Chye, P. R. Skeathm C. Y. Su, and I. Lindau, “New and unified model for Schottky barrier and III-V insulator interface states formation,” J. Vac. Sci. Technol., 16, 1422 (1979).
[96] G. Brammertz, H.-C.Lin, K. Martens, D. Mercier, S. Sioncke, A. Delabie, W. E. Wang, M. Caymax, M. Meuris, and M. Heyns, “Capacitance-voltage characterization of GaAs-Al2O3 interfaces,” Appl. Phys. Lett., 93, 183504 (2008).
[97] N. Goel, P. Majhi, C. O. Chui, W. Tsai, D. Choi, and J. S. Harris, “InGaAs metal-oxide-semiconductor capacitors with HfO2 gate dielectric grown by atomic-layer deposition,” Appl. Phys. Lett., 89, 163517 (2006).
[98] S. J. Koester, E. W. Kiewra, Y. Sun, D. A. Neumayer, J. A. Ott, M. Copel, and D. K. Sadana, “Evidence of electron and hole inversion in GaAs metal-oxide-semiconductor capacitors with HfO2 gate dielectrics and alpha-Si/SiO2 interlayers,” Appl. Phys. Lett., 89, 042104 (2006).
[99] C. Marchiori, D. J. Webb, C. Rossel, M. Richter, M. Sousa, C. Gerl, R. Germann, C. Andersson, and J. Fompeyrine, “H plasma cleaning and a-Si passivation of GaAs for surface channel device applications,” J. Appl. Phys., 106, 114112 (2009).
[100] D. J. Webb, J. Fompeyrine, S. Nakagawa, A. Dimoulas, C. Rossel, M. Sousa, R. Germann, S. F. Alvarado, J. P. Locquet, C. Marchiori, H. Siegwart, A. Callegari, E. Kiewra, Y. Sun Y, J. De Souza, and N. Hoffmann, “In-situ MBE Si as passivating interlayer on GaAs for HfO2 MOSCAP’s: effect of GaAs surface reconstruction,” Microelec. Eng., 84, 2142 (2007).
[101] T. Yasuda, N. Miyata, and A. Ohtake, “Influence of initial surface reconstruction on the interface structure of HfO2/GaAs,” Appl. Surf. Sci., 254, 7565 (2008).
[102] N. Negoro, S. Anantathanasarn, and H. Hasegawa, “Effects of Si deposition on the properties of Ga-rich (4×6) GaAs (001) surfaces,” J. Vac. Sci. Technol., B 21, 1945 (2003).
[103] G. Brammertz, K. Martens, S. Sioncke, A. Delabie, M. Caymax, M. Meuris, and M. Heyns, “Characteristic trapping lifetime and capacitance-voltage measurements of GaAs metal-oxide-semiconductor structures,” Appl. Phys. Lett., 91, 133510 (2007).