以氮化鎵為基材所開發的電晶體已被證實不論電子遷移率、高功率、耐高溫等特性與傳統矽基材料相比皆有數個量級的提升，以有機氣相沉積技術生長的氮化鎵品質，已可以滿足在光電元件上的應用如發光二極體(light emitting diodes)、雷射二極體(laser diodes)，然而在深紫外光(DUV)波長范圍內工作光電二極體(photodiodes)對於薄膜的電性要求較高，對於磊晶薄膜之中的摻雜物的濃度以及均勻度皆有更高的要求。

為滿足此性質要求，其一困難便是p-type摻雜效率(doping efficient)仍然不夠高，由於Mg的活化能較高，只有約(1-5%)的Mg能成功激活成電洞載子。其中delta doping摻雜方式是提升薄膜電性的方式。相比於unifom doping，delta doping 生長的p-type GaN 有著更高的電洞載子濃度因而有更佳的薄膜電性。

本研究透過數值模擬的方式建立穩態Unifom doping模型及暫態Delta (δ) doping模型，以近耦合腔體分析其製程特性，其中包含二維與三維腔體幾何比較分析、薄膜沉積物種分析、摻雜製程分析，以提高摻雜製程掌控性。

The transistors developed with gallium nitride as the substrate has been proven to have several orders of magnitude improvement over traditional silicon-based materials, regardless of electron mobility, high power, and high temperature resistance. The GaN quality growth by metal organic vapor chemical deposition technology can already meet the application of optoelectronic components such as light emitting diodes, laser diodes. But the photodiodes that works in the deep ultraviolet (DUV) wavelength range has higher electrical requirements and higher requirements for the concentration and uniformity of the dopants in the epitaxial thin film.

One difficulty to meet this requirement is that the p-type doping efficiency is still not enough. Due to the high activation energy of Mg, only about (1-5%) of Mg can be successfully activated into a hole carriers. The delta doping method is a way to improve the electrical properties of the thin film. Compared with uniform doping, delta doping grown p-type GaN has higher hole carrier concentration and better film electrical properties.

In this study, the steady-state Uniform doping model and the unsteady-state Delta (δ) doping model are established by numerical simulation. The Close- Coupled Showerhead reactor will be applied. The study include two-dimensional and three-dimensional reactor geometric comparison analysis、thin-film deposition species analysis、doping process analysis. In order to improve the control of the doping process.

[1] R. Zuo, H. Yu, N. Xu, and X. He, “Influence of Gas Mixing and Heating on Gas-Phase Reactions in GaN MOCVD Growth”, ECS Journal of Solid State Science and Technology, Vol 1, pp. 46-53, July 2012.
[2] Y. B. Pan, Z. J. Yang, Y. Lu, M. Lu, C. Y. Hu, T. J. Yu, X. D. Hu, and G. Y. Zhang “Improvement of properties of p-GaN by Mg delta doping”, Chinese Physics Letters., Vol 21, No. 10, May 2004.
[3] M. L. Nakarmi, K. H. Kim, J. Li, J. Y. Lin, and H. X. Jiang, “Enhanced p-type conduction in GaN and AlGaN by Mg-δ-doping”, Appl. Phys. Lett., Vol 82, pp. 3041-3043, May 2003.
[4] C. Bayram, J. L. Pau, R. McClintock, and M. Razeghi. “Delta-doping optimization for high quality p-type GaN”, J. Appl. Phys., Vol 104, pp. 1-6, October 2008.
[5] T. Liu, Z. Hong, and Y. Yuan,“Theoretical investigation on gas-phase reaction mechanism of Cp2Mg in p- type doping process of Group III nitrides”, Computational and Theoretical Chemistry., Vol 1177, pp. 112793, May 2020.
[6] X. Yulun, S. Huang, Z. Zheng, B. Fan, Z. Wu, H. Jiang, and G. Wang, “Effects of growth pressure on the properties of p-GaN layers”, Journal of Crystal Growth., Vol 325, pp. 32-35, June 2011.
[7] Y. Nagai, H. Niwa, A. Hashimoto, and A. Yamamoto, “Adduct formation of CP2Mg with NH3 in MOVPE growth of Mg-doped InN”, Phys. stat. sol., Vol 4, No. 7, pp. 2457–2460, June 2007.
[8] D. Sengupta, S. Mazumder, W. Kuykendall, Lowry, and S. A. Lowry, “Combined ab initio quantum chemistry and computational fluid dynamics calculations for prediction of gallium nitride growth”, Journal of Crystal Growth., Vol 279, pp. 369-382, March 2005.
[9] Y. J. Zhou, Z. Q. Li, A. EL Boukili, and Z. M. Simon Li, “Process simulation of p-doping in GaN and related group III nitrides”, Phys. stat. sol., Vol 4, No. 5, pp. 1694-1697, April 2007.
[10] Z. Zhang, H. Fang, H. Yan, Z. Jiang, J. Zheng, and Z. Gan,“Influencing factors of GaN growth uniformity through orthogonal test analysis”, Applied Thermal Engineering., Vol 91, pp. 53-61, August 2015.
[11] Y. Chen, H. Wu, G. Yue, Z. Chen, Z. Zheng, Z. Wu, G. Wang, and H. Jiang, “Enhanced Mg Doping Efficiency in P-Type GaN by Indium-Surfactant-Assisted Delta Doping Method”, Applied Physics Express., Vol 6, No. 4, pp. 041001, March 2013.
[12] 林暐捷，「MOCVD 行星式腔體之模型建立與傳輸現象分析」，國立中央大學，碩士論文，民國107年。
[13] H. Zhang , R. Zuo, and G. Zhang. “Effects of reaction-kinetic parameters on modeling reaction pathways in GaN MOVPE growth”, Journal of Crystal Growth., Vol 478, pp. 193-204, August 2017.