本論文旨在進行高電壓SiC蕭基二極體之模擬與研製。由於SiC雜質擴散之不易，在不增加製程及設備成本之情形下，我們比較3種不同的邊緣終結(edge termination，ET)結構設計，對提昇SiC蕭基二極體崩潰電壓之效果。
　　於本論文中，我們結合兩種邊緣終結結構進行二維數值模擬與實驗分析，除針對磊晶層摻雜條件對於崩潰電壓的影響加以分析外，尚比較不同終結結構對於崩潰電壓提升之影響。根據模擬所得的結果，我們提出可改善崩潰電壓SiC蕭基二極體之邊緣終結結構設計，以作為後續實驗設計之基礎。在實驗方面，我們分別以Ni及Al/Ti/Au製作n型SiC之歐姆接觸，並詳細分析退火條件對接觸電阻之影響。實驗結果顯示，以Ni為歐姆接觸之製程已有相當之穩定性，所製作出之歐姆電阻可小於3.12×10-6 Ω-cm2 ；而Al/Ti/Au/n-SiC歐姆接觸則具有9.72×10-6 Ω-cm2之低阻值。
　　於蕭基二極體之製作方面，我們分別利用浮動式金屬環(FMR)、浮動式金屬環加上高阻值蕭基電位障平板(FMR+RESP)、以及氧化層邊緣結構用來改善蕭基二極體之崩潰電壓。實驗結果顯示，以浮動式金屬環加上高阻值蕭基電位障平板邊緣結構改善SiC蕭基二極體之崩潰電壓效果較佳，崩潰特性的改善可達74.2%。

　　In this thesis, the design and fabrication of high voltage 4H-SiC Schottky barrier diodes (SBDs) with various edge termination (ET) designs is presented. Two-dimensional simulation to investigate the effects of floating metal ring (FMR) and resistive Schottky field plate (RESP) on the breakdown voltage of SBDs is reported. The optimal FMR structure has been determined through the theoretical calculations. To further improve the breakdown voltage, a novel ET structure combining RESP and FMR structures was proposed.
　　Au/Ti/Al Ohmic contacts to n-type 4H-SiC with specific contact resistance (SCR) as low as 9.72×10-6 Ω-cm2 is reported for the first time. Ohmic behavior with SCRs in 10-5~10-6 Ω-cm2 range was usually achieved when annealed at 800 oC or above. X-ray diffraction results of the alloyed contact layer show that formation of titanium silicides might be responsible for the Ohmic contact at the metal/n-SiC interface.
　　Base on a n/n+-4H-SiC epi-wafer with a 10 μm thick epilayer with a doping of 5×1015 cm-3, various ET schemes were proposed and investigated. As compared to results of three ET design, the best structures can increase of 74.2% in VBD has been obtained.

[1] C. Haberstroh, R. Helbig, R.A. Stein, J. Appl. Phys.76, pp. 509-513, 1997.
[2] W.V. Muench, I. Pfaffeneder, J. Appl. Phys. 48, pp. 4831-4833, 1977.
[3] G.A. Slack, J. Appl. Phys. 35, pp. 3460-3466, 1964.
[4] T. P. Chow and R. Tyagi, IEEE Trans. Electron Devices, vol. 41, pp. 1481, 1994.
[5] B. J. Baliga, “Modern Power Devices”, Wiley, New York, 1987.
[6] M.Sze, Physics of Semiconductor Devices,2ed. (John Wiley & Sons, New York, 1981).
[7] G. R. Fisher and P. Barnes, “Toward a unified view of polytypism in silicon carbide,” Phil. Mag. B, vol. 61, no. 2, pp. 217-236, Feb. 1990.
[8] O. Kordina, Ph.D Thesis, Department of Physics and Measurement Technology,
Linköping University, Linköping, Sweden, 1994.
[9] R. Singh, J. A. Cooper, Fellow, IEEE, M. R. Melloch, Fellow, IEEE, T. P. Chow, Senior Member, IEEE, and J. W. Palmour, Member, IEEE, “SiC Power Schottky and PiN Diodes”, IEEE Trans. Electron. Devices, vol. 49, pp. 665-672, 2002.
[10] M. Murakami, Master. Sci. Rep. 5, pp. 273-317. 1990.
[11] H. Morkoc,S. Strite, G.B. Gao, M.E. Lin, B. Sverdlov, M. Burns, J. Appl. Phys. 76, pp. 1363-1398. 1994.
[12] R.F. Davis, G. Kelner, M. Shur, J.W. Palmour, J.A. Edmond, Proc. IEEE 79 , pp. 677-701. 1991.
[13] K.V. Vasilevskii, Sov. Phys. Semicond. 26, pp. 994-999. 1992.
[14] J.A. Edmond, H.J. Kim, R.F. Davis, Mater. Res. Soc. Symp. Proc. 52, pp. 157. 1986.
[15] J. Crofton, P. G. McMullin, J.R. Williams, M.J. Bozak, J. Appl. Phys. 77, p. 1317. 1995.
[16] Ajira Itoh, Tsunenobu Kimoto, and Hiroyuki Matsunami, ”High performance of high-voltage 4H-SiC schottky barriers diode,”IEEE Electron Device Lett., Vol. 16, no. 6, pp. 280, 1995.
[17] M. Bhatnagar, P. K. Mclarty, and B.J. Baliga, “Silicon carbide high voltage (400 V) Schottky barrier diodes”, IEEE Electron Device Lett., vol. 13, p. 501, sept. 1992.
[18] R. Rupp, M. Treu, A. Mauder, E. Griebl, W. Werner, W. Bartsch, and D. Stephani, “Performance and reliability issues of SiC Schottky diodes”, Mat. Sci. Forum, vol. 338-342, pp. 1167-1170, 2000.
[19] Lien, F. C. T. So, and M. A. Nicolet, “An improved forward I-V method for nonideal Schottky diodes with high series resistance”, IEEE Trans. Electron Devices, vol. ED-31, no. 10, pp. 1502,1984.
[20] Bohlin, “Generalized Norde plot including determination of the ideality factor”, J. Appl. Phys., vol. 60, no. 3, pp. 1223, 1986.
[21] S. Y. Han, J. Y. Shin, B. T. Lee, and J. L. Lee, “Microstructural interpretation of Ni ohmic contact on n-type 4H-SiC ”, J. Vac. Sci. Technol. B 20, p. 1496. 2002.
[22] R. Kakabakov, L. K. Kolaklieva, N. Hristeva, G. Lepoeva, and K. Zekentes, “Thermally Stable Low Resistivity Ohmic Contacts for High Power and Temperature SiC Device Applications”, Proc. 23rd International Conference on Microelectronics, p. 205. 2002.
[23] S. Y. Han, K. H. Kim, J. K. Kim, H. W. Jang, K. H. Lee, N. K. Kim, E. D. Kim, and J. J. Lee, “Ohmic contact formation mechanism of Ni on n-type 4H-SiC”, Appl. Phys. Lett. 79, p. 1816. 2001.
[24] Ts. Marinova, A. Kakanakova-Georgieva, V. Krastev, R. Kakanakov, M. Neshev, L. Kassamakova, O. Noblanc, C. Arnodo, S. Cassette, C. Brylinski, B. Pecz, G. Radnoczi, Gy. Vincze, “Nickel based ohmic contacts on SiC”, Materials Science and Engineering B46, pp. 223-226. 1997.
[25] J. Crofton, P. G. McMullin, J. R. Williams, and M. J. Bozack, “High-temperature ohmic contact to n-type 6H-SiC using nickel”, J. Appl. Phys. 77, (3), pp. 1317-1319. 1995.
[26] L. G. Fursin, J. H. Zhao and M. Weiner, “Nickel ohmic contacts to p- and n-type 4H-SiC”, ELECTRONICS LETTERS 16th vol. 37 no. 17. August 2001.
[27] S. K. Lee, C. M. Zetterling, M. Östling, J. P. Palmquist, H. Högberg, and U. Jansson, “Low resistivity ohmic titanium carbide contacts to n- and p-type 4H-silicon carbide”, Solid-State Electron., vol. 44, pp. 1179-1186, 2000.
[28] S. K. Lee, C. M. Zetterling, E. Danielsson, M. Östling, J. P. Palmquist, H. Högberg, and U. Jansson, “Electrical characterization of TiC ohmic contacts to aluminum ion implanted 4H-Silicon carbide”, Appl. Physl. Lett., vol. 77, pp. 1478-1480, 2000.
[29] S. K. Lee, E. Danielsson, C. M. Zetterling, M. Östling, J. P. Palmquist, H. Högberg, and U. Jansson, “The formation and characterization of epitaxial titanium carbide contacts to 4H-SiC”, Mat. Res. Soc. Proc., vol. 622, pp. T6.9 2000.
[30] J. Crofton, P.G. McMullin, J.R. Williams, M.J. Bozack, J. Appl. Phys. 77, pp. 1317-1319. 1995.
[31] J. Crofton, E.D. Luckowski, J.R. Williams, T. Issacs-Smith, M.J. Bozack, R. Siergiej, presented at Silicon Carbide and Related Materials 1995 Conference, pp. 569-572. 1996.
[32] N. Lundberg and M. Ostring, Solid-State Electron. 39, 11, p. 1559.
[33] Ts. Marinova et al., Mater. Sci. Eng. B46, p. 223, 1997.
[34] G. Constantinidis, N. Kornilios, K. Zekentes, J. Stoemenos and L. di. Cioccio, Mater. Sci. Eng. B46, p. 176, 1997.
[35] L. Kassamakova et al., Mater. Sci. Eng. B61-62, p. 291, 1999.
[36] Liliana Kassamakova et al., IEEE Trans. Electron Devices, 46, 3, p. 605, 1999.
[37] Roumen Kakanakov et al., Mater. Sci. Eng. B80, p. 374, 2001.
[38] J. Kriz, K. Gottfried, Th. Scholz, Ch. Kaufmann, T. GeBner, “Ohmic contacts to n-type polycrystalline SiC for high-temperature micromechanical applications”, Material Science and Engineering B46, pp. 180-185. 1997.
[39] A. Itoh, T. Kimoto and H. Matsunami, “Efficient Power Schottky Rectifiers of 4H-SiC”, proc. International Symposium on Power Semiconductor Device & ICs, Yokohama, 1995.
[40] Shui Jinn Wang and Jiann Tyng Tzeng, “The double-metal schottky power rectifier: an adjustable schottky barrier height low-power-loss diode”, submitted to 1997 International Conference on Solid State Device sand Materials (SSDM’97).
[41] G. Constantinidis, “Processing Technologies for SiC”, pp. 161-170, IEEE, 1997.
[42] M. Bhatnagar, H. Nakanishi, P. K. Mclarty, B. J. Baliga, B. Patnaik, and N. Parikh, “Comparison of Ti and Pt Silicon Carbide Schottky Rectifiers”, IEEE, 1992.