氮化鋁鎵/氮化鎵半導體之異質接面處因為優選c-自發極化(試片表面指向基板)之極化特性，使電子聚集於導帶的不連續面並受異質接面之量子井侷限其飄移方向而形成高濃度之二維電子氣通道，而因量子井形成於低摻雜區，能有效降低雜質散射與晶格散射，使通道擁有高電子遷移率之特性，更因氮化鎵本身為寬能隙半導體材料，使氮化鋁鎵/氮化鎵之異質結構半導體元件特性表現更能達到高崩潰電場、高溫以及高頻的工作等優勢。在本論文中，以此氮化鋁鎵/氮化鎵異質結構製作多重通道增強型(enhancement mode)之金氧半高電子遷移率場效電晶體(MOSHEMTs)。
在多重通道結構的部分，本論文中以雷射干涉微影術結合光電化學(photoelectrochemical, PEC)濕式蝕刻法蝕刻出柵狀之多重通道，而此結構能有效提升閘極兩側與通道的接觸面積，促使閘極偏壓之電場能有效增加，使臨限電壓(threshold voltage, VTH)正偏移並增加閘極控制力、提升最大轉移電導(gm(max))、減少次臨限擺幅(subthreshold swing , S.S.)、減少閘極漏電及改善高頻特性。
在增強型元件的部分，為了降低氮化鋁鎵的極化效應，使得載子通道內電子濃度下降，在提升的同時更提升閘極控制能力，將採用光電化學濕式蝕刻法完成閘極掘入結構製作，並且透過脈衝雷射沉積法(pulsed laser deposition technique)製作鈮酸鋰(Lithium Niobate, LiNbO3)鐵電薄膜作為閘極氧化層，結合閘極掘入結構與該鐵電薄膜之自發極化特性相輔抵銷氮化鋁鎵/氮化鎵異質結構內之極化效應，達到空乏二維電子氣通道之效用，成功製作出增強型高速電子遷移率電晶體。

In this research, we used AlGaN/GaN heterostructure to fabricate multiple channel enhancement mode metal-oxide-semiconductor high-electron-mobility transistors (MOSHEMTs). We used laser interference photolithography method to fabricate multiple channel structure. This structure could increase contact area between side walls of gate and AlGaN/GaN heterostructure, and hence could effectively increase the electric field of gate bias voltage. Multiple channel structure also could shift threshold voltage positively and increase gate controllability, increase maximum transconductance, decrease gate leakage current and improve high frequency performance. The AlGaN/GaN heterostructure generally formed depletion mode transistors. To fabricate enhancement mode transistors, we used gate-recessed structure combined with the ferroelectric LiNbO3 film as the oxide layer using a pulsed laser deposition system to deplete the polarization of AlGaN/GaN heterostructure. Finally, we successfully fabricated multiple channel enhancement mode metal-oxide-semiconductor high-electron-mobility transistors.

第一章
[1]T. P. Chow and R. Tyagi, “Wide bandgap compound semiconductors for superior high-voltage unipolar power devices,” IEEE Trans. Electron devices, vol. 41, pp. 1481-1483, 1994.
[2]張家華, “異質結構AlGaN/GaN金屬接面特性之研究,” 國防大學中正理工學院電子工程研究所碩士論文, 2001.
[3]L. F. Eastman, V. Tilak, J. Smart, B. M. Green, E. M. Chumbes, R. Dimitrov, H. Kim, O. S. Ambacher, N. Weimann, T. Prunty, M. Murphy, W. J. Schaff and J. R. Shealy, “Undoped AlGaN/GaN HEMTs for microwave power application,” IEEE Trans. Electron Devices, vol. 48, pp. 479-485, 2001.
[4]F. Sacconi, A. D. Carlo, P. Lugli and H. Morkoç, “Spontaneous and piezoelectric polarization effects on the output characteristics of AlGaN/GaN heterojunction modulation doped FETs,” IEEE Trans. Electron Devices, vol. 48, pp. 450-457, 2001.
[5]I. P. Smorchkova, C. R. Elsass, J. P. Ibbetson, R. Vetury, B. Heying, P.Fini, E. Haus, S. P. DenBaars, J. S. Speck and U. K. Mishra, “Polarization-induced charge and electron mobility in AlGaN/GaN heterostructures grown by plasma-assisted molecular-beam expitaxy,” J. Appl. Phys., vol. 86, pp. 4520-4526, 1999.
[6]O. Ambacher, B. Foutz, J. Smart, J. R. Shealy, N. G. Weimann, K. Chu, M. Murphy, A. J. Sierakowski, W. J. Schaff and L. F. Eastman, “Two dimensional electron gases induced by spontaneous and piezoelectric polarization in undoped AlGaN/GaN heterostructures,” J. Appl. Phys., vol. 87, pp.334-344, 2000.
[7]H. Morkoc, A. D. Carlo and R. Cingolani, “GaN-based modulation doped FETs and UV detectors,” Solid-State Electron, vol. 46, pp. 157-202, 2002.
[8]R. Dimitrov, M. Murphy, J. Smart, W. Schaff, J. R. Shealy and L. F. Eastman, “Two-dimensional electron gases in Ga-face and N-face AlGaN/GaN heterostructures grown by plasma-induced molecular beam exitaxy and metalorganic chemical vapor deposition on sapphire,” J. Appl. Phys., vol. 87, pp. 3375-3380, 2000.
[9]O. Ambacher, J. Smart, J. R. Shealy, N. G. Weimann, K. Chu, M. Murphy, W. J. Schaff and L. F. Eastman, “Two-dimensional electron gases induced by spontaneous and piezoelectric polarization charges in N- and Ga-face AlGaN/GaN heterostructures,” J. Appl. Phys, vol. 85, pp. 3222-3233, 1999.
[10]M. Micovic, T. Tsen, M. Hu, P. Hashimoto, P. J. Willadsen, I. Milosavljevic, A. Schmitz, M. Antcliffe, D. Zhender, J. S. Moon, W. S. Wong and D. Chow, “GaN enhancement/depletion-mode FET logic for mixed signal applications,” Electron. Lett., vol. 41, 2005.
[11]Y. Cai, Z. Cheng, W. C. W. Tang, K. M. Lau and K. J. Chen, “Monolithically integrated enhancement/depletion-mode AlGaN/GaN HEMT inverters and ring oscillators using CF4 plasma treatment,” IEEE Trans. Electron Devices, vol. 53, pp. 2223-2230, 2006.
[12]D. Hisamoto, W. C. Lee, J. Kedzierski, E. Anderson, H. Takeuchi, K. Asano, T. J. King, J. Bokor and C. Hu, “A folded‐channel MOSFET for deep‐sub‐tenth micron era,” IEEE International Electron Devices Meeting Technical Digest, pp. 1032‐1034, 1998.
第二章
[1]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, pp. 3222-3233, 1999.
[2]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, pp. 334-344, 2000.
[3]I. P. Smorchkova, C. R. Elsass, J. P. Ibbetson, R. Vetury, B. Heying, P. Fini, E. Haus, S. P. DenBaar, J. S. Speck and U. K. Mishra, “Polarization-induced charge and electron mobility in AlGaN/GaN heterostructures grown by plasma-assisted molecular-beam epitaxy,” J. Appl. Phys., vol. 86, pp. 4520-4526, 1999.
[4]F. Sacconi, A. D. Carlo, P. Lugli and H. Morkoc, “Spontaneous and piezoelectric polarization effects on the output characteristics of AlGaN/GaN heterojunction modulation doped FETs,” IEEE Trans. Electron Devices, vol. 48, pp. 450-457, 2001.
[5]M. A. Khan, M. S. Shur, J. N. Kuzunia, Q. Chen, J. Burm and W. Schaff, “Temperature activated conductance in GaN/AlGaN heterostructure field effect transistors operating at temperatures up to 300 °C,” Appl. Phys. Lett., vol. 66, pp. 1083-1085, 1995.
[6]E. H. Chen, D. T. Mclnturff, T. P. Chin, M. R. Melloch and J. M. Woodall, “Use of annealed low-temperature grown GaAs as a selective photoetch-stop layer,” Appl. Phys. Lett., vol. 68, pp. 1678-1680, 1996.
[7]L. H. Huang and C. T. Lee, “Investigation and analysis of AlGaN MOS devices with an oxidized layer grown using the photoelectrochemical oxidation method,” J. Electrochem. Soc., vol. 154, pp. H862-H866, 2007.
[8]W. D. Kingery, H. K. Bowen and D. R. Uhlmann, “Introduction to Ceramics,” 1976.
[9]W. H. Zachariasen, Skr. Norske Vid-Ada, Oslo, Mat. Naturv. No.4, 1928.
[10]A. A. Ballman, “Growth of Piezoelectric and Ferroelectric Materials by the CzochraIski Technique,” J. Am. Ceram. Soc., vol. 48, pp. 112-113, 1965.
[11]D. W. Kim, S. H. Lee and T. W. Noh, “Structural and nonlinear optical properties of epitaxial LiNbO3 films grown by pulsed laser deposition,” Mater. Sci. Eng. B-Adv. Funct. Solid-State Mater., vol. 56, pp. 251-255, 1998.
[12]R. I. Tomov, T. K. Kabadjova, P. A. Atanasov, S. Tonchev, M. Kaneva, A. Zherikhin and R. W. Eason, “LiNbO3 optical waveguides deposited on sapphire by electric-field-assisted pulsed laser deposition,” Vacuum, vol. 58, pp. 396-403, 2000.
[13]H. K. Lam, J. Y. Dai and H. L. W. Chan, “Orientation controllable deposition of LiNbO3 films on sapphire and diamond substrates for surface acoustic wave device application,” J. Cryst. Growth, vol. 268, pp. 144-148, 2004.
[14]M. Veithen and Ph. Ghosez, “First-principles study of the dielectric and dynamical properties of lithium niobate,” Phys. Rev. B, vol. 65, pp. 214302-1-214302-12, 2002.
[15]L. Z. Hao, J. Zhu and Y. Liu, S. Wang, H. Zeng, X. Liao, Y. Liu, H. Lei, Y. Zhang, W. Zhang and Yanrong, “Integration and electrical properties of epitaxial LiNbO3 ferroelectric film on n-type GaN semiconductor,” Thin Solid Films, vol. 520, pp. 3035-3038, 2012.
[16]P. J. Hansen, Y. Terao, Y. Wu, R. A. York, U. K. Mishra and J. S. Speck, “LiNbO3 thin film growth on (0001)-GaN,” J. Vac. Sci. Technol. B, vol. 23, no. 1, pp. 162-167, 2005.
[17]L. Z. Hao, J. Zhu and Y. R. Li, “Integration between LiNbO3 ferroelectric film and AlGaN/GaN system,” Materials Science Forum vol. 687, pp. 303-308, 2011.
[18]K. Nassau, H. J. Levinstein and G. M. Loiacono, “Ferroelectric lithium niobate. 2. Preparation of single domain crystals,” J. Phys. Chem. Solids, vol. 27, pp. 989-996, 1966.
[19]S. C. Abrahams, J. M. Reddy and J. L. Bernstein, “Ferroelectric lithium niobate. 3. Single crystal X-ray diffraction study at 24 °C,” J. Phys. Chem. Solids., vol. 27, pp. 997-1012, 1966.
[20]D. L. Staebler and J. J. Amodei, “Thermally fixed holograms in LiNbO3,” Ferroelectrics, vol. 3, pp. 107-113, 1972.
[21]M. G. Clark, F. J. DiSalvo, A. M. Glass and G. E. Peterson, “Electronic structure and optical index damage of iron‐doped lithium niobate,” J. Phys. Chem. Solids., vol. 59, pp. 6209-6219, 1973.
[22]S. Tan, T. Gilbert, C. Y. Hung and T. E. Schlesinger, “Sputter deposited c-oriented LiNbO3 thin films on SiO2,” J. Appl. Phys., vol. 79, pp. 3548-3553, 1996.
[23]G. Namkoong, K. K. Lee, S. M. Madison, W. Henderson, S. E. Ralph and W. A. Doolittle, “III-nitride integration on ferroelectric materials of lithium niobate by molecular beam epitaxy,” Appl. Phys. Lett., vol. 87, pp. 171107-1-171107-3, 2005.
[24]X. Q. Chen, H. Yamada, Y. Terai, T. Horiuchi, K. Matsushige and P. S. Weiss, “Strong substrate effect in local poling of ultrathin ferroelectric polymer films,” J. Vac. Sci. Technol. B, vol. 353, pp. 259-263, 2005.
[25]F. Balestra, S. Cristoloveanu, M. Benachir, J. Brini and T. Elewa, “Double-gate silicon-on-insulator transistor with volume inversion: a new device with greatly enhanced performance,” IEEE Electron Device Lett., vol. 8, pp. 410-412, 1987.
[26]D. Hisamoto, W. C. Lee, J. Kedzierski, E. Anderson, H. Takeuchi, K. Asano, T. J. King, J. Bokor and C. Hu, “A folded‐channel MOSFET for deep‐sub‐tenth micron era,” IEEE International Electron Devices Meeting Technical Digest, pp. 1032‐1034, 1998.
[27]K. Ohi, J. T. Asubar, K. Nishiguchi and T. Hashizume, “Current stability in multi-mesa-channel AlGaN/GaN HEMTs,” IEEE Trans. Electron Devices, vol. 60, pp. 2997-3004, 2013.
第三章
[1]P. E. Riley, “Plasma etching of aluminum metallizations for ultralarge scale integrated circuits,” J. Electrochem. Soc., vol. 140, pp. 1518-1522, 1993.
[2]S. K. Ghandhi, “VLSI fabrication principles,” John Wiley & Sons, pp. 635, 1994.
[3]C. T. Lee, Y. J. Lin and C. H. Lin, “Nonalloyed ohmic mechanism of TiN interfacial layer in Ti/Al contact to (NH4)2Sx-treated n-type GaN layers,” J. Appl. Phys., vol. 92, pp. 3825-3829, 2002.
[4]S. J. Lee and C. R. Crowell, “Parasitic source and drain resistance in high-electron-mobility transistor,” Solid-State Electron., vol. 28, pp.659-668, 1985.
[5]Q. Z. Liu, L. S. Yu, F. Deng, S. S. Lau, Q. Chen, J. W. Yang and M. A. Khan, “Study of contact formation in AlGaN/GaN heterostructures,” Appl. Phys. Lett., vol. 71, pp. 1658-1660, 1997.
[6]M. E. Lin, Z. Ma, F. Y. Huang, Z. F. Fan, L. H. Allen and H. Morkoç, “Low resistance ohmic contacts on wide band-gap GaN,” Appl. Phys. Lett., vol. 64, pp. 1003-1005, 1994.
[7]M. Kanamura, T. Ohki, T. Kikkawa, K. Imanishi, T. Imada, A. Yamada and N. Hara, “Enhancement-mode GaN MIS-HEMTs with n-GaN/i-AlN/n-GaN triple cap layer and high-k gate dielectrics,” IEEE Electron Device Lett., vol. 31, pp. 189-191, 2010
[8]C. H. Choi and C. J. Kim, “Fabrication of a dense array of tall nanostructures over a large sample area with sidewall profile and tip sharpness control,” Nanotechnology, vol. 17, pp. 5326-5333, 2006.
[9]J. D. Boor, N. Geyer, U. Gösele and V. Schmidt, “Three-beam interference lithography：upgrading a Lloyd’s interferometer for single-exposure hexagonal patterning,” Opt. Lett., vol. 34, pp. 1783-1785, 2009.
[10]J. W. Son, S. S. Orlov, B. Phillips and L. Hesselink, “Pulsed laser deposition of single phase LiNbO3 thin film waveguides,” J. Electroceram., vol. 17, pp. 591-595, 2006.
[11]S. Higuchi and I. Tsukada, “Pulsed-laser deposition of LiNbO3 thin films at low oxidation gas pressure with pure Ozone,” Jpn. J. Appl. Phys., vol. 42, pp. L1066-L1068, 2003.
[12]J. Gonzalo, C. N. Afonso, J. M. Ballesteros, A. Grosman and C. Ortega, “Li deficiencies in LiNbO3 films prepared by pulsed laser deposition in a buffer gas,” J. Appl. Phys., vol. 82, pp. 3129-3133, 1997.
第四章
[1]楊昌霖,李清庭, “鈮酸鋰結合光電化學法閘極掘入之增強型金氧半高速電子遷移率電晶體之研究,”國立成功大學微電子所碩士論文, 2014.
[2]L. H. Huang and C. T. Lee, “Investigation and analysis of AlGaN MOS devices with an oxidized layer grown using the photoelectrochemical oxidation method,” J. Electrochem. Soc., vol. 154, pp. H862-H866, 2007.
[3]K. Ohi, J. T. Asubar, K. Nishiguchi and T. Hashizume, “Current stability in multi-mesa-channel AlGaN/GaN HEMTs,” IEEE Trans. Electron Devices, vol. 60, pp. 2997-3004, 2013.
[4]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, pp. 081002-1-081002-5, 2009.
[5]M. Alsharef, M. Christiansen, R. Granzner, E. Ture, R. Quay, O. Ambacher and F. Schwierz, “RF performance of trigate GaN HEMTs,” IEEE Trans. Electron Devices, vol. 63, pp. 4255-4261, 2016.
[6]K. Ohi and T. Hashizume, “Reduction of current collapse in the multi-mesa-channel AlGaN/GaN HEMT,” Phys. Status Solidi C, vol. 9, pp. 899-902, 2012.