臺灣博碩士論文加值系統

III-V族材料氮化鎵(GaN)，具有高崩潰電場、高熱傳導係數、較小的介電常數與較大的截止頻率等優異的材料特性。因此氮化鋁鎵/氮化鎵高電子遷移率電晶體常被應用在高功率、高溫度以及高頻率的電路中操作。而當元件應用於訊號傳輸時，元件的線性度會影響訊號失真的程度，因此元件線性度可以做為判斷元件優劣的依據。

此外氮化鋁鎵/氮化鎵高電子遷移率電晶體本身的元件特性，在無偏壓的情況下二維電子氣一直存在著，因此元件是屬於空乏型(Depletion-mode)元件，故必須施加一負偏壓才能使元件關閉，這樣的操作模式對於功率元件的應用上是一大缺點，如此會增加電路設計的複雜度。因此為了降低電路系統設計之成本與降低能源之浪費，設計出增強型(Enhancement-mode) GaN材料電晶體成為相當重要的議題。

本論文主要是利用半導體模擬軟體Sentaurus TCAD來模擬AlGaN/GaN HEMT元件特性，首先介紹模擬使用之物理模型，與引述模擬電流值與量測電流值電性匹配完成的結果後，確保模擬上使用的物理模型之準確性。將元件改良為含有雙AlGaN/GaN異質接面之雙通道元件，並進行研究。隨後進行材料層複合結構層比較，基於雙通道元件具有雙轉導(Gm)峰值的特性，經由調整兩個轉導峰值的位置與差異，設計出較平坦且較寬的Gm，藉此提升元件的線性度。最後藉由在閘極下方做部分p-type摻雜，並搭配材料層厚度改變或掘入式閘極等方式，將空乏型元件改良為增強型元件，成功設計出具有高線性度之增強型雙通道氮化鋁鎵/氮化鎵高電子遷移率電晶體。

The GaN material of III-V compounds has the excellent properties of material such as high breakdown voltage, high thermal conductivity, small permittivity and high cut-off frequency. It always has been operated in high power, high temperature and high frequency circuits because of the excellent characteristics of carrier transmission of AlGaN/GaN high electron mobility transistors (HEMTs). In the applications of communication transmission, linearity of device has effect in the degree of distortion of signal. Therefore, linearity is an important factor of device quality.

However, in the condition of zero bias that two-dimensional electron gas (2DEG) always exists because of the own properties of AlGaN/GaN HEMTs. Therefore, we have to exert a negative bias to close the device because of the device is depletion-mode. It is a drawback in the applications of power electronic devices so the circuit design is more complicate. Therefore, for reducing the cost of circuit design and the wasting of resources that how to design the enhancement-mode GaN material transistor is an important issue.

In this thesis, Sentaurus TCAD is used to simulate device characteristics of AlGaN/GaN HEMTs. First, we will introduce physical models and simulate the electrical characteristics of AlGaN/GaN HEMTs, in which the physical parameters will be calibrated so that the simulation results matches the measured data from a reference data. This process ensures the accuracy of the subsequent simulation work. Next, we will rebuilt our device in to a double-channel structure which’s basic design consult to a reference that has double AlGaN/GaN heterojunctions. After that we will compare the property of composite structure before we have a device which has a flat and wide transconductance peak after we modulate the variation and location of twin transconductance peaks of double-channel AlGaN/GaN HEMTs. The linearity is improved. Last, we use recessed-gate and changing the thick of material layer with partially p-type doping which’s location is under gate that make the depletion-mode device turning into enhancement-mode. Thus we successfully design an enhancement-mode double-channel AlGaN/GaN HEMT which has high linearity.

摘要 i
ABSTRACT ii
誌謝 iv
目錄 v
表目錄 vii
圖目錄 viii
第一章 緒論 1
1-1前言 1
1-2研究動機與目的 3
1-3論文架構 8
第二章 高電子遷移率電晶體原理與研究背景簡介 9
2-1氮化物材料極化效應與各材料層影響 9
2-1.1氮化物材料極化效應 9
2-1.2各材料層的影響 13
2-2增強型元件製造方式 17
2-2.1掘入式閘極 17
2-2.2 Fluorine Implantation and Fluorine-Based Plasma Treatment 18
2-2.3 p-AlGaN Gate and p-GaN Gate 19
第三章 模擬軟體物理模型介紹與AlGaN/GaN HEMT元件模擬分析 23
3-1關於HEMT物理模型簡介 23
3-1.1基本的電流電壓計算模型 24
3-1.2遷移率模型(Mobility Model) 27
3-1.3極化模型(Polarization Model) 28
3-1.4複合機制模型(Recombination Model) . 29
3-1.5邊界條件(Boundary Condition) 30
3-1.6數值方法(Numerical Method) 31
3-1.7繪圖表示(Plot) 33
3-2介紹模擬電流值與實驗量測匹配值匹配結果 34
3-3雙通道元件結構 39
3-4雙通道結構之有與無AlN層比較 41
3-5雙通道結構之複合結構比較 43
第四章 增強型元件模擬結果與討論 54
4-1於閘極下方上層氮化鋁鎵層底部p-type摻雜 54
4-2於閘極下方上層氮化鋁鎵層頂部p-type摻雜 59
4-3藉由改變空乏型元件設計改良 69
第五章 結論 72
5-1元件尺寸說明 74
參考文獻 75

[1] Lester F. Eastman and U.K. Mishra, “The toughest transistor yet GaN transistors,” IEEE Spectrun, Vol. 39, Issue. 5, pp. 28-33, May 2002.

[2] 徐偉峰，2007，氮化鋁鎵/氮化鎵高電子遷移率功率電晶體應用於切換式直流對直流升壓轉換器之研究，國立中央大學，碩士論文。

[3] U. K. Mishra, P. Parikh, and Y. Wu, “ AlGaN/GaN HEMTs—An Overview of Device Operation and Applications,” Proceedings of the IEEE, Vol. 90, Issue. 6, pp. 1022- 1031, Jun. 2002

[4] U. K. Mishra, Likun Shen, Thomas E. Kazior, and Y. Wu, “ GaN-Based RF Power Devices and Amplifiers,” Proceedings of the IEEE, Vol. 96, Issue. 2, pp. 287- 305,Feb. 2008

[5] David Hall, “Understanding Intermodulation Distortion Measurements,”Electronic Design Technologies Communications, Oct. 2013

[6] 蔡翊翔，2010，微波功率放大器線性度改善研究，國立中央大學，碩士論文。

[7] Nakasha, Y. ,Fujitsu Labs. Ltd., Atsugi, Nagahara, M. ; Tateno, Y. ; Takahashi, H. ,“A Low-Distortion and High-Efficiency E-mode GaAs Power FET Based on a New Method to Improve Device Linearity Focused on gm Value,” Electron Devices Meeting 1999. IEDM '99. Technical Digest. International, pp.5-8, Dec. 1999

[8] Yueh-Chin Lin, Edward Yi Chang,Hiroshi Yamaguchi,Wei-Cheng Wu, and Chun-Yen Chang, “ A δ-Doped InGaP/InGaAs pHEMT With Different Doping Profiles for Device-Linearity Improvement,” IEEE Trans. on Electron Devices, Vol. 54, No. 7,pp. 1617-1625, Jul. 2007

[9] 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 and doped AlGaN/GaN heterostructures,” Journal of applied physics, Vol. 87, No. 1, pp.334-344, Jan.2000

[10]徐至鴻，2012，閘極掘入式增強型氮化鋁鎵/氮化鎵功率場效電晶體之研製，
國立中央大學，碩士論文。

[11] 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 charges in N- and Ga-face AlGaN/GaN heterostructures,” Journal of applied physics, Vol. 85, No. 6, pp.3222-3233, Mar.1999

[12] Rashmi, Abhinav Kranti, S. Haldar, R.S. Gupta, “ An accurate charge control model
for spontaneous and piezoelectric polarization dependent two-dimensional electron gas sheet charge density of lattice-mismatched AlGaN/GaN HEMTs,” Journal Solid-State Electronics, Vol. 46, No. 5, pp.621-630, May. 2002

[13] S. R. Lee,D. D. Koleske, K. C. Cross, J. A. Floro, and K. E. Waldrip, “ In situ
measurements of the critical thickness for strain relaxation in AlGaN/GaN heterostructures,” Journal of applied physics, Vol. 85, No. 25, pp.6164-6166, Dec. 2004

[14] Subramaniam ARULKUMARAN, Takashi EGAWA and Hiroyasu ISHIKAWA, “
Studies on the Influences of i-GaN, n-GaN, p-GaN and InGaN Cap Layers in AlGaN/GaN High-Electron-Mobility Transistors,” Japanese Journal of Applied Physics, Vol. 44, No. 5A, pp.2953-2960, May. 2005

[15] G. Parish,S. Keller,S. P. Denbaars andU. K. Mishra, “SIMS investigations into the effect of growth conditions on residual impurity and silicon incorporation in GaN and AlxGa1−xN,” Journal of Electronic Materials, Vol. 29, No. 1, pp. 15-20, Jan. 2000

[16] Niraj Man Shrestha, Yuen Yee Wang, Yiming Li, and E.Y. Chang, “Simulation Study of AlN Spacer Layer Thickness on AlGaN/GaN HEMT,” Japanese Journal of Applied Physics, Vol. 53, No. 4S, pp.14-17, Feb. 2014

[17] Bruce M. Green, Kenneth K. Chu, E. Martin Chumbes, Joseph A. Smart, James R. Shealy, and Lester F. Eastman, “The Effect of Surface Passivation on the Microwave Characteristics of Undoped AlGaN/GaN HEMT’s,” IEEE Electron Device Lett, Vol. 21, NO. 6, pp. 268-270, Jun. 2000

[18] Ting-Hsiang Hung, Pil Sung Park, Sriram Krishnamoorthy, Digbijoy N. Nath, and Siddharth Rajan, “Interface Charge Engineering for Enhancement-Mode GaN MISHEMTs,” IEEE Electron Device Lett., Vol. 35, No. 3, pp. 312–314 , Mar. 2014.

[19] Wataru Saito, Yoshiharu Takada, Masahiko Kuraguchi, Kunio Tsuda, and Ichiro Omura, , “Recessed-Gate Structure Approach Toward Normally-Off High-Voltage AlGaN/GaN HEMT for Power Electronics Applications,” IEEE Trans. on Electron Devices, Vol. 53, No. 2, pp. 356–362 Feb. 2006.

[20] W. B. Lanford, T. Tanaka, Y. Otoki, W. Saito, Y. Takada, M. Kuraguchi, K. Tsuda, and I. Omura,, “Recessed-gate enhancement-mode GaN HEMT with high threshold voltage,” IEEE Electron Lett., Vol. 41, No. 7, pp. 449–450, Mar. 2005.

[21] Hongwei Chen, Maojun Wang, Kevin J. Chen , “ Enhancement-mode AlGaN/GaN HEMTs Fabricated by Standard Fluorine Ion Implantation,” CS MANTECH Conference, May 17th-20th, 2010, Portland, Oregon, USA

[22] 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.

[23] S. Martin-Horcajo, M. J. Tadjer, M. F. Romero, R. Cuerdo, F. Calle, “Fabrication
and characterization at high temperature of AlGaN/GaN enhancement-mode HEMTs,” Electron Devices (CDE),Spanish Conference on, Feb. 2011. Palma de Mallorca

[24] Y. Uemoto, M. Hikita, H. Ueno, H. Matsuo, H. Ishida, M. Yanagihara, T. Ueda, T. Tanaka, and D. Ueda, “Gate Injection Transistor (GIT)- A Normally-Off AlGaN/GaN Power Transistor Using Conductivity Modulation,” IEEE Trans. on Electron Devices, Vol. 54, No. 12, pp. 3393–3399,Dec. 2007.

[25] O. Hilt, A. Knauer, F. Brunner, E. Bahat-Treidel and J. Würfl, “Normally-off AlGaN/GaN HFET with p-type GaN Gate and AlGaN Buffer,” Proceedings of The 22nd International Symposium on Power Semiconductor Devices & ICs, pp.347-350 , Jun. 2010. Hiroshima

[26] C. S. Suh, A. Chini, Y. Fu, C. Poblenz, J. S. Speck, U. K. Mishra, “p-GaN/AlGaN/GaN Enhancement-Mode HEMTs,” 64th Device Research Conference on, Jun. 2006. State College, PA, USA

[27] Takashi Katsuno, Masakazu Kanechika, Kenji Itoh, Koichi Nishikawa, Tsutomu
Uesugi, and Tetsu Kachi, “Improvement of Current Collapse by Surface Treatment and Passivation Layer in p-GaN Gate GaN High-Electron-Mobility Transistors,” Japanese Journal of Applied Physics 52, pp. 04CF08-1–5, Mar. 2013.

[28] The introduction of sentaurus TCAD –S-Device, Published by Synopsys Sentaurus Device

[29]林佳億，2014，雙通道氮化鋁鎵/氮化鎵高電子遷移率電晶體之線性度提升，
國立雲林科技大學，碩士論文。

[30] Rongming Chu, Yugang Zhou, Jie Liu, Deliang Wang, Kevin J. Chen, “AlGaN-GaN Double-Channel HEMTs,” IEEE Trans. on Electron Devices, Vol. 52, No. 4, pp. 438–446, Apr. 2005.

[31] L. Shen, S. Heikman, B. Moran, R. Coffie, N.-Q. Zhang, D. Buttari, I. P. Smorchkova, S. Keller, S. P. DenBaars, and U. K. Mishra, “AlGaN/AlN/GaN High-Power Microwave HEMT,” IEEE Electron Device Lett, Vol. 22, No. 10, pp.457-459, Oct. 2001.

[32] Fanna Meng,Jincheng Zhang,Hao Zhou, Juncai Ma, Junshuai Xue, Lisha Dang,
Linxia Zhang, Ming Lu, Shan Ai, Xiaogang Li, and Yue Hao, “Transport
characteristics of AlGaN/GaN/AlGaN double heterostructures with high electron mobility,” Journal of applied physics, pp.023707-1-6, Jul. 2012.

[33] Madhusudan Singha and Jasprit Singh, “Design of high electron mobility devices with composite nitride channels,” Journal of applied physics, Vol. 64, Number. 4, pp.2498-2509, Aug. 2003.