本論文利用感應耦合式電漿蝕刻系統進行乾式蝕刻從而完成閘極掘入之製程。閘極掘入的目的是為了藉由調控閘極金屬與通道間之距離，增加閘極對通道的控制能力，降低元件臨界電壓。為了完成閘極掘入，本論文分析了各項主要製程參數對蝕刻效果的影響。由結果可以知道蝕刻功率對蝕刻速率有相當大的影響。
我們成功利用感應耦合式電漿蝕刻系統完成了閘極掘入深度為14nm的閘極掘入氮化鋁鎵/氮化鎵高速電子遷移率電晶體。傳統高速電子遷移率電晶體的最大轉導和臨界電壓分別為88mS/mm和-4.2V，而閘極掘入高速電子遷移率電晶體的最大轉導和臨界電壓分別為115mS/mm和-1.33V。

The use of inductively coupled plasma etcher system to GaN gate recess process is demonstrated. Gate recess modulates the distance between the gate metal and the two-dimensional electron gas. The threshold voltage and related device performance can be adjusted. In order to accomplish the gate recess process, etching parameters and behavior of the inductively coupled plasma etcher system is investigated. It can be found out that the etch rates were strongly influenced by ICP power.
The recessed gate AlGaN/GaN high electron mobility transistors with a recess depth of 14nm have been successfully fabricated. For the conventional AlGaN/GaN HEMTs, the transconductance and the threshold voltage were 88 mS/mm and – 4.2 V. For the recessed-gate AlGaN/GaN HEMTs, the transconductance and the threshold voltage were 115 mS/mm and – 1.33 V.

Reference
[1] W. Schockley, “Circuit elements utilizing semiconductive material,” U.S.Patent, vol. N.2567, pp. 347, 1951.
[2] H. L. S. R. Dingle, A. C. Gossard, and W. Wiegmann, “Electron mobilities in modulation‐doped semiconductor heterojunction superlattices,” Applied Physics Letters vol. 33, no. 7, pp. 665, 1978.
[3] S. J. Pearton, F. Ren, A. P. Zhang, and K. P. Lee, “Fabrication and performance of GaN electronic devices,” Materials Science and Engineering: R: Reports, vol. 30, no. 3–6, pp. 55-212, 12/1/, 2000.
[4] Z. W. Yoshinori Uzawa, Akira Kawakami, and Bokuji Komiyama, “Submillimeter wave responses in NbN/AlN/NbN tunnel junctions,” Appl. Phys. Lett., vol. 66, no. 15, pp. 66, 1995.
[5] T. P. Chow, and R. Tyagi, “Wide bandgap compound semiconductors for superior high-voltage unipolar power devices,” Electron Devices, IEEE Transactions on, vol. 41, no. 8, pp. 1481-1483, 1994.
[6] J. S. Foresi, and T. D. Moustaka, “Metal contact to gallium nitride,” Appl. Phys. Lett., vol. 62, no. 22, pp. 2860, 1993.
[7] Z. Z. Bandić, P. M. Bridger, E. C. Piquette, T. C. McGill, R. P. Vaudo, V. M. Phanse, and J. M. Redwing, “High voltage (450 V) GaN Schottky rectifiers,” Applied Physics Letters, vol. 74, no. 9, pp. 1266, 1999.
[8] R. Gaska, J. W. Yang, A. Osinsky, Q. Chen, and M. A. Khana, “Electron transport in AlGaN/GaN heterostructures grown on 6H-SiC substrates,” Appl. Phys. Lett., vol. 72, no. 6, pp. 707, 1998.
[9] S.J.Pearton, “GaN and related matterials.”
[10] J. I. Pankove, E. A. Miller, and J. E. Berkeyheiser, "GaN electroluminescent diodes." pp. 78-78.
[11] H. P. Xin, R. J. Welty, and C. W. Tu, “GaN0.011/P0.989/GaP double-heterostructure red light-emitting diodes directly grown on GaP substrates,” Photonics Technology Letters, IEEE, vol. 12, no. 8, pp. 960-962, 2000.
[12] J. A. Edmond, K. Hua-Shuang, V. Dmitriev, and C. H. Carter, "Blue/UV emitters from SiC and its alloys." pp. V16-V17.
[13] S.Kim, K.Lee, N. S.J, and Y.Huh, “Inductively coupled plasma etching of III-N layers by using a Cl2/N2 plasma,” Journal of the Korean Physical Society, vol. 41, no. 2, pp. L184, 2002.
[14] C. L. Chao, W. C. Chou, C. Y. Shi, K. J. Ma, and T. T. Chen, “Investigation of material removal mechanisms involved in ICP etching of INGaN/GaN,” journal of C.C.I.T, vol. 34, no. 2, 2006.
[15] B. Lu, M. Sun, and T. Palacios, “An etch-stop barrier structure for GaN Hi
gh-Electron-Mobility Transistors,” IEEE ELECTRON DEVICE LETTERS, vol. 34, no. 3, pp. 369, 2013.
[16] J. Y. Liao, and P. M. Batteate, “Etch characterization of packaged IC samples in an RIE with endpoint detection by ICP source for failure analysis applications,” 2005.
[17] P. M. Asbeck, E. T. Yu, S. S. Lau, G. J. Sullivan, J. V. Hove, and J. Redwing, “Piezoelelctric charge density in AlGaN-GaN HFETs,” Electronic Letters, vol. 33, no. 14, pp. 1230, 1997.
[18] F. Bernardini, and V. Fiorentini, “Spontaneous polarization and piezoelectric constants of III-V nitrides.”
[19] Y. C. Kong, Y. D. Zheng, C. H. Zhou, Y. Z. Deng, S. L. Cu, B. Shen, R. Zhang, P. Han, R. L. Jiang, and Y. SHi, “Influence of polarization and doping in AlGaN barrier on the two-dimensional electron gas in AlGaN/GaN heterostructure,” ACTA PHYSICA SINICA, vol. 53, no. 7, pp. 2320, 2003.
[20] H. Huang, Y. C. Liang, G. S. Samudra, and C.-F. Huang, “Design of novel normally-off AlGaN/GaN HEMTs with combined gate recess and floating charge structures,” IEEE, pp. 554, 2013.
[21] C. Lee, W. Lu, E. Piner, and I. Adesida, “Recessed-gate GaN MESFET using ICP-RIE for high temperature microwave applications.”
[22] Y. Pei, R. Chu, L. Shen, N. A. Fichtenbaum, Z. Chen, D. Brown, S. Keller, S. P. Denbaars, and U. K. Mishra, “Effect of Al composition and gate recess on power performance of AlGaN/GaN,” IEEE ELECTRON DEVICE LETTERS, vol. 29, no. 4, pp. 300, 2008.
[23] G. Xie, E. Xu, J. Lee, N. Hashemi, B. Zhang, F. Y. Fu, and W. T. Ng, “Breakdown-voltage-enhancement technique for RF-based AlGaN/GaN HEMTs with a source-connected air-bridge field plate,” IEEE ELECTRON DEVICE LETTERS, vol. 33, no. 5, pp. 670, 2012.
[24] G. Xie, E. Xu, J. Lee, N. Hashemi, F. Y.Fu, B. Zhang, and W.T.Ng, “Breakdown voltage enhancement for power AlGa-GaN HEMTSs with air-bridge field plate,” IEEE, 2011.
[25] S. Rajabil, A. A. Oroui, H. Amini, Moghadam, and S. E. J. Mahabadi, “A novel double field-plate power HEMT based on AIGaN/GaN for performance improvement,” ICSCCN, pp. 272, 2011.
[26] S.-H. Y. Ching-Sung Lee, and Ming-Yuan Lin, “Gamma-gate MOS-HEMTs by methods of ozone water oxidation and shifted exposure,” IEEE ELECTRON DEVICE LETTERS, vol. 32, no. 2, pp. 152, 2011.
[27] N.-Q. Zhang, S. Keller, G. Parish, S. Heikman, S. P. DenBaars, and U. K. Mishra, “High breakdown GaN HEMT with overlapping gate structure,” IEEE ELECTRON DEVICE LETTERS, vol. 21, no. 9, pp. 421, 2000.
[28] A. M. MALIK, “Technology and physics of gate recessed GaN-AlGaN FETs.”
[29] D. Yandong, H. Weihua, Y. Wei, Z. Yanbo, X. Ying, Z. Renping, and Y. Fuhua, “Research progress of enhancement-mode AlGaN/GaN HEMTs,” Semiconductor Technology, vol. 36, no. 10, pp. 771, 2011.
[30] S. A. Smith, C. A. Wolden, M. D. Bremser, A. D. Hanser, R. F. Davis, and W. V. Lampert, “High rate and selective etching of GaN, AlGaN, and AlN using an inductively coupled plasma,” Applied Physics Letters, vol. 71, no. 25, pp. 3631, 1997.
[31] E. Zhirnov, S. Stepanov, A. Gott, W. N. Wang, Y. G. Shreter, D. V. Tarkhin, and N. I. Bochkareva, “ICP etching of III-nitride based laser structure with Cl2–Ar plasma assisted by Si coverplate material,” Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, vol. 23, no. 4, pp. 687, 2005.
[32] M.-H. Tasi, “Application of reactive-ion etching(RIE) on GaN material.”
[33] N. KetteniJ3, M. Eickelkamp, A. Noculak, R. H. Jansen, and A. Vescan, “Processing and characterization of recessed-gate AlGaN/GaN HFETs,” IEEE, pp. 151, 2008.