在本篇論文中，我們利用成長在矽基板上的氮化鋁鎵/氮化鎵試片製作金氧半高電子遷移率電晶體，實驗的目標為以能夠阻止閘極下方二維電子氣形成的掘入式閘極結構來達到增強型操作。
我們使用Al2O3作為閘極氧化層，同時比較RCA表面處理及H2SO4/ H2O2表面處理對元件的影響，最後量測的結果，H2SO4/H2O2做表面處理和採用閘極優先製程的掘入式閘極金氧半電晶體，臨界電壓為5V，次臨界擺幅為467mV/decade，場效電子遷移率可達到125 cm2/V-s，氧化層和半導體間介面態密度以電導法求出最大值約為7.93 x1013 cm-2eV-1。由於較高的介面態密度，掘入式閘極金氧半高電子遷移率電晶體有電流崩塌效應。
元件的崩潰特性上，擁有最高崩潰電壓的元件為以氧化鋁作為氧化層的掘入式閘極金氧半高電子遷移率電晶體，在Lgd=20μm時崩潰電壓可以達到1565V，配合導通電阻7.18mΩ-cm2，BFOM值為341 MW/ cm2。

In this study, AlGaN/GaN Metal-Oxide-Semiconductor High Electron Mobility Transistors (MOSHEMT) on a silicon substrate were fabricated. The purpose is to use a recessed-gate structure to achieve enhance mode operation, since the recessed-gate structure blocks the formation of two dimensional electron gas under the gate.
Al2O3 was used as the gate dielectric, and two surface treatments were compared using atomic layer deposition. From the results we found that the recessed-gate MOSHEMT with the H2SO4/H2O2 treatment prior to depositing ALD aluminum oxide shows a threshold voltage of 5V, a subthreshold swing of 467mV/decade, and a field effect mobility of 125cm2/V-s. The interface state density between oxide and semiconductor was 7.93x1013 cm-2eV-1 extracted using the conductance method. However, the recessed gate MOSHEMT shows significant current collapse effect due to high interface state density.
About the off-state breakdown characteristics, we found that the one which shows the highest breakdown voltage was a MOSHEMT with aluminum oxide as the gate oxide using H2SO4/H2O2 treatment. For devices with a Lgd=20μm, breakdown voltage can reach 1565V. With a on-resistance of 7.18mΩ-cm2, the BFOM is 341 MW/ cm2.

第1章 序論 1
1.1 前言 1
1.2 文獻回顧 2
1.3研究方向簡介與論文架構 7
1.3.1 研究方向簡介 7
1.3.2論文架構 7
第2章 元件介紹及實驗設計 14
2.1 氮化鋁鎵/氮化鎵材料介紹 14
2.1.1自發性極化效應 14
2.1.2 壓電極化效應 14
2.2 基板的選擇 15
2.3 場平板(Field plate)結構 15
2.4 元件隔離方式(Isolation) 16
2.5閘極掘入方式 17
2.6 實驗設計 17
第3章 光罩設計及元件製程 22
3.1氮化鋁鎵/氮化鎵高電子遷移率電晶體設計流程 22
3.2蝕刻對準記號 23
3.3蝕刻閘極區域 25
3.4閘極氧化層製作 27
3.5歐姆接觸製作 28
3.6 元件隔離區域製作 29
3.7閘極金屬沉積 30
第4章 元件量測結果分析 31
4.1 電容量測分析 31
4.1.1 電容-電壓量測分析 33
4.1.2介面態密度分析 37
4.2 正向電性分析 49
4.2.1 TLM測試元件量測 49
4.2.2不同閘極蝕刻深度的電流-電壓特性 50
4.2.3 不同表面處理的電流-電壓特性 51
4.2.4不同閘極長度的電流-電壓特性 55
4.2.5. 線性元件和圓型元件的電流-電壓特性 57
4.3 崩潰特性分析 60
4.4電流崩塌效應特性分析 61
4.5電子缺陷與閘極控制 64
第5章 結論與未來工作 66
參考文獻 67

參考文獻
[1] N. Ikeda, Y. Niiyama, H. Kambayashi, Y. Sato, T. Nomura, S. Kato, and S. Yoshida, "GaN power transistors on Si substrates for switching applications," Proceedings of the IEEE, vol. 98, pp. 1151-1161, July 2010.
[2] L. F. Eastman and U. K. Mishra, "The toughest transistor yet [GaN transistors]," IEEE Spectrum vol. 39, no.5, pp. 28-33, May 2002.
[3] U. K. Mishra, P. Parikh, and Y.-F. Wu, "AlGaN/GaN HEMTs—an overview of device operation and applications," Proceedings of the IEEE, vol. 90, no.6, pp. 1022 - 1031, June 2002.
[4] B. J. Baliga, "Power semiconductor device figure of merit for high-frequency applications," IEEE Electron Device Lett., vol. 10, no. 10, pp. 455 - 457, Oct. 1989.
[5] B. Gil, III-Nitride semiconductors and their modern devices: OUP Oxford, 2013.
[6] A. Khan, J. N. Kuznia, J. M. V. Hove, N. Pan, and J. Carter, "Observation of a two-dimensional electron gas in low pressure metalorganic chemical vapor deposited GaN-AlGaN heterojunctions," Appl. Phys. Lett., vol. 60, no. 24, pp. 3027–9, 1992.
[7] 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., vol. 69, no. 10, pp. 1438 - 1440, 1996.
[8] S. Yoshida, H. Ishii, J. Li, D. Wang, and M. Ichikawa, "A high-power AlGaN/GaN heterojunction field-effect transistor," Solid-State Electronics, vol. 47, no. 3, pp. 589-592, 2003.
[9] A. Sarua, H. Ji, M. Kuball, M. J. Uren, and T. Martin, K. J. Nash, K. P. Hilton, and R. S. Balmer, "Piezoelectric strain in AlGaN/GaN heterostructure field-effect transistors under bias," Appl. Phys. Lett., vol. 88, no. 10, pp. 103502 - 103502-3, Mar. 2006.
[10] S. Karmalkar and U. K. Mishra, "Enhancement of breakdown voltage in AlGaN/GaN high electron mobility transistors using a field plate," IEEE Trans. Electron Devices, vol. 48, no. 8, pp. 1515 - 1521, Aug. 2001.
[11] H. Xing, Y. Dora, A. Chini, S. Heikman, S. Keller, and U. K. Mishra, "High breakdown voltage AlGaN-GaN HEMTs achieved by multiple field plates," IEEE Electron Device Lett., pp. 161 - 163, Apr. 2004.
[12] B. Lu and T. Palacios, "High breakdown ( > 1500 V ) AlGaN/GaN HEMTs by substrate-transfer technology," IEEE Electron Device Lett., vol. 31, no. 9, pp. 951 - 953, Sep. 2010.
[13] M. A. Khan, X. Hu, G. Sumin, A. Lunev, J. Yang, R. Gaska, and M. S. Shur, "AlGaN/GaN metal oxide semiconductor heterostructure field effect transistor," IEEE Electron Device Lett., vol. 21, no. 2, pp. 63 - 65, 2000.
[14] P. D. Yet, B. Yang, K. K. Ng, J. Bude, G. D. Wilk, A. S. Halder, and J. C. M. Hwang, "GaN MOS-HEMT using atomic layer deposition Al2O3 as gate dielectric and surface passivation," International Journal of High Speed Electronics and Systems, vol. 14, no.3 pp. 791 - 796, 2004.
[15] S. Yagi, M. Shimizu, H. Okumura, H. Ohashi, K. Arai, Y. Yano, and N. Akutsu, "1.8 kV AlGaN/GaN HEMTs with high-k/oxide/SiN MIS structure," ISPSD, pp. 261 - 264, May, 2007.
[16] M. A. Khan, Q. Chen, C. J. Sun, J. W. Yang, M. Blasingame, M. S. Shur, and H. Park, "Enhancement and depletion mode GaN/AlGaN heterostructure field effect transistors," Appl. Phys. Lett., vol. 68, no. 4, pp. 514 - 516, 1996.
[17] X. Hu, G. Simin, J. Yang, M. A. Khan, R. Gaska, and M. S. Shur, "Enhancement mode AlGaN/GaN HFET with selectively grown pn junction gate," Electronics Lett., vol. 36, no. 8, pp. 753 - 754, 2000.
[18] Y. Cai, Y. Zhou, K. M. Lau, and K. J. Chen, "Control of threshold voltage of AlGaN/GaN HEMTs by fluoride-based plasma treatment: from depletion mode to enhancement mode," IEEE Trans. on Electron Devices, vol. 53, no. 9, pp. 2207 - 2215, Sep. 2006.
[19] W. B. Lanford, T. Tanaka, Y. Otoki, and I. Adesid, "Recessed-gate enhancement-mode GaN HEMT with high threshold voltage," Electronics Letters, vol. 41, no. 7, pp. 449 - 450, Mar. 2005.
[20] T. Oka and T. Nozawa, "AlGaN/GaN recessed MIS-gate HFET with high-threshold-voltage normally-off operation for power electronics applications," IEEE Electron Device Lett., vol. 29, no. 7, pp. 668 - 670, 2008.

[21] M. Kanamura, T. Ohki, T. Kikkawa, K. Imanishi, T. Imada, A. Yamada, and Naoki 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, no. 3, pp. 189 - 191, 2010.
[22] Chihoko Mizue, Yujin Hori, Marcin Miczek, Tamotsu Hashizume, "Capacitance–Voltage Characteristics of Al2O3 / AlGaN / GaN Structure and State Density Distribution at Al2O3/AlGaN Interface " Japanese Journal of Applied Physics, 50 (2011) 021001
[23] 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, no.3, pp. 450 - 457, Mar. 2001.
[24] 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, no. 6, pp. 3222 - 3233, 1999.
[25] R. Gaska, A. Osinsky, J. W. Yang, and M. S. Shur, "Self-heating in high-power AlGaN-GaN HFET’s," IEEE Electron Device Lett., vol. 19, no.3, pp. 89-91, Mar. 1998.
[26] S. C. Lee, M. W. Ha, J. C. Her, S. S. Kim, J. Y. Lim, K. S. Seo, and M. K. Han, "High breakdown voltage GaN Schottky barrier diode employing floating metal rings on AlGaN/GaN hetero-junction," Proc. of 17th ISPSD, pp. 247 - 250, May, 2005.
[27] S. Karmalkar, J. Deng, M. S. Shur, and R. Gaska, "RESURF AlGaN/GaN HEMT for high voltage power switching," IEEE Electron Device Lett., vol. 22, no. 8, pp. 373 - 375, Aug. 2001.
[28] T. Wu, Z. B. Hao, G. Tang, and Y. Luo, "Dry etching characteristics of AlGaN/GaN heterostructures using inductively coupled H2/Cl2, Ar/Cl2 and BCl3/Cl2 plasmas," Jpn. J. Appl. Phys., vol. 42, pp. 257 - 259, Mar. 2003.
[29] Y. Hori, Z. Yatabe, T. Hashizume, "Characterization of interface states in Al2O3/AlGaN/GaN structures for improved performance of high-electron-mobility transistors," J. Appl. Phys., vol. 114, pp. 244503 1-8, Dec. 2013