Effects of the strain relaxation of an AlGaN barrier layer induced by various cap layers on the transport properties in AlGaN/GaN heterostructures

doi:10.1088/1674-1056/20/9/097701

Abstract The strain relaxation of an AlGaN barrier layer may be influenced by a thin cap layer above, and affects the transport properties of AlGaN/GaN heterostructures. Compared with the slight strain relaxation found in AlGaN barrier layer without cap layer, it is found that a thin cap layer can induce considerable changes of strain state in the AlGaN barrier layer. The degree of relaxation of the AlGaN layer significantly influences the transport properties of the two-dimensional electron gas (2DEG) in AlGaN/GaN heterostructures. It is observed that electron mobility decreases with the increasing degree of relaxation of the AlGaN barrier, which is believed to be the main cause of the deterioration of crystalline quality and morphology on the AlGaN/GaN interface. On the other hand, both GaN and AlN cap layers lead to a decrease in 2DEG density. The reduction of 2DEG caused by the GaN cap layer may be attributed to the additional negative polarization charges formed at the interface between GaN and AlGaN, while the reduction of the piezoelectric effect in the AlGaN layer results in the decrease of 2DEG density in the case of AlN cap layer.

Keywords: cap layer strain relaxation AlGaN/GaN transport properties

Received: 19 January 2011
Revised: 25 April 2011
Accepted manuscript online:

PACS:	77.65.Ly	(Strain-induced piezoelectric fields)
	72.10.Fk	(Scattering by point defects, dislocations, surfaces, and other imperfections (including Kondo effect))
	72.80.Ey	(III-V and II-VI semiconductors)

Cite this article:

Liu Zi-Yang(刘子扬), Zhang Jin-Cheng(张进成), Duan Huan-Tao(段焕涛), Xue Jun-Shuai(薛军帅),Lin Zhi-Yu(林志宇), Ma Jun-Cai(马俊彩), Xue Xiao-Yong(薛晓咏), and Hao Yue(郝跃) Effects of the strain relaxation of an AlGaN barrier layer induced by various cap layers on the transport properties in AlGaN/GaN heterostructures 2011 Chin. Phys. B 20 097701

[1]	özgür A, Kim W, Fan Z, Botchkarev A, Salvador A, Mohammad S N, Sverdlov B and Morkocc H 1995 Electron. Lett. 31 1389
[2]	Lei S Y, Shen B and Zhang G Y 2008 Acta Phys. Sin. 57 2386 (in Chinese)
[3]	Zhang J F, Zhang J C and Hao Y 2004 Chin. Phys. 13 1334
[4]	Ambacher O, Smart J, Shealy J R, Weimann N G, Chu K, Murphy M, Schaff W J, Eastman L F, Dimitrov R, Wittmer L, Stutzmann M, Rieger W and Hilsenbeck J 1999 J. Appl. Phys. 85 3222
[5]	Wright A F and Nelson J S 1995 Phys. Rev. B 51 7866
[6]	Gessmann T, Graff J W, Li Y L, Waldron E L and Schubert E F 2002 J. Appl. Phys. 92 3740
[7]	Yu E T, Dang X Z, Yu L S, Qiao D, Asbeck P M, Lau S S, Sullivan G J, Boutros K S and Redwing J M 1998 Appl. Phys. Lett. 73 1880
[8]	Selvaraj S L, Ito T, Terada Y and Egawa T 2007 Appl. Phys. Lett. 90 173506
[9]	Chang P C, Yu C L, Chang S J, Lin Y C and Wu S L 2007 IEEE Sens. J. bf7 1289
[10]	Shen B, Someya T and Arakwa Y 2000 Appl. Phys. Lett. 76 2746
[11]	Feng Z H, Zhou Y G, Cai S J and Lau K M 2004 Appl. Phys. Lett. 85 5248
[12]	Smorchkova I P, Chen L, Mates T, Shen L, Heikman S, Moran B, Keller S, DenBaars S P, Speck J S and Mishra U K 2001 J. Appl. Phys. 90 5196
[13]	Floro J A, Follstaedt D M, Provencio P, Hearne S J and Lee S R 2004 J. Appl. Phys. 96 7087
[14]	Lee S R, Koleske D D, Cross K C, Floro J A, Waldrip K E, Wise A T and Mahajan S 2004 Appl. Phys. Lett. 85 6164
[15]	Deguchi T, Ichiryu D, Toshikawa K, Sekiguchi K, Sota T, Matsuo R, Azuhata T, Yamaguchi M, Yagi T, Chichibu S and Nakamura S 1999 J. Appl. Phys. 86 1860
[16]	Tanaka M, Nakahata S, Sogabe K, Nakata H and Tabioka M 1997 Jpn. J. Appl. Phys. Part 2 36 1062
[17]	Moram M A, Barber Z H and Humphreys C J 2007 J. Appl. Phys. 102 023505
[18]	Wright A F 1997 J. Appl. Phys. 82 2833
[19]	Metzger T, Höpler R, Born E, Ambacher O, Stutzmann M, Stömmer R, Schuster M, Göbel H, Christiansen S, Albrecht M and Strunk H P 1998 Philos. Mag. A 77 1013
[20]	Heying B, Wu X H, Keller S, Li Y, Kapolnek D, Keller B P, DenBaars S P and Speck J S 1996 Appl. Phys. Lett. 68 643
[21]	Aggerstam T, Lourdudoss S, Radamson H H, Sjödin M, Lorenzini P and Look D C 2006 Thin Solid Films 515 705
[22]	Liu B, Lu Y W, Jin G R, Zhao Y, Wang X L, Zhu Q S and Wang Z G 2010 Appl. Phys. Lett. 97 262111
[23]	Heikman S, Keller S, Wu Y, Speck J S, DenBaars S P and Mishra U K 2003 J. Appl. Phys. 93 10114
[24]	Gao Z Y, Hao Y, Zhang J C, Li P X and Gu W P 2009 Chin. Phys. B 18 4970
[25]	Xu X Q, Liu X L, Yang S Y, Liu J M, Wei H Y, Zhe Q S and Wang Z G 2009 Appl. Phys. Lett. 94 112102

[1]	Cascade excitation of vortex motion and reentrant superconductivity in flexible Nb thin films Liping Zhang(张丽萍), Zuyu Xu(徐祖雨), Xiaojie Li(黎晓杰), Xu Zhang(张旭), Mingyang Qin(秦明阳), Ruozhou Zhang(张若舟), Juan Xu(徐娟), Wenxin Cheng(程文欣), Jie Yuan(袁洁), Huabing Wang(王华兵), Alejandro V. Silhanek, Beiyi Zhu(朱北沂), Jun Miao(苗君), and Kui Jin(金魁). Chin. Phys. B, 2023, 32(4): 047302.
[2]	Reverse gate leakage mechanism of AlGaN/GaN HEMTs with Au-free gate Xin Jiang(蒋鑫), Chen-Hao Li(李晨浩), Shuo-Xiong Yang(羊硕雄), Jia-Hao Liang(梁家豪), Long-Kun Lai(来龙坤), Qing-Yang Dong(董青杨), Wei Huang(黄威),Xin-Yu Liu(刘新宇), and Wei-Jun Luo(罗卫军). Chin. Phys. B, 2023, 32(3): 037201.
[3]	Simulation design of normally-off AlGaN/GaN high-electron-mobility transistors with p-GaN Schottky hybrid gate Yun-Long He(何云龙), Fang Zhang(张方), Kai Liu(刘凯), Yue-Hua Hong(洪悦华), Xue-Feng Zheng(郑雪峰),Chong Wang(王冲), Xiao-Hua Ma(马晓华), and Yue Hao(郝跃). Chin. Phys. B, 2022, 31(6): 068501.
[4]	Improved device performance of recessed-gate AlGaN/GaN HEMTs by using in-situ N₂O radical treatment Xinchuang Zhang(张新创), Mei Wu(武玫), Bin Hou(侯斌), Xuerui Niu(牛雪锐), Hao Lu(芦浩), Fuchun Jia(贾富春), Meng Zhang(张濛), Jiale Du(杜佳乐), Ling Yang(杨凌), Xiaohua Ma(马晓华), and Yue Hao(郝跃). Chin. Phys. B, 2022, 31(5): 057301.
[5]	Current oscillation in GaN-HEMTs with p-GaN islands buried layer for terahertz applications Wen-Lu Yang(杨文璐), Lin-An Yang(杨林安), Fei-Xiang Shen(申飞翔), Hao Zou(邹浩), Yang Li(李杨), Xiao-Hua Ma(马晓华), and Yue Hao(郝跃). Chin. Phys. B, 2022, 31(5): 058505.
[6]	High linearity AlGaN/GaN HEMT with double-V_th coupling for millimeter-wave applications Pengfei Wang(王鹏飞), Minhan Mi(宓珉瀚), Meng Zhang(张濛), Jiejie Zhu(祝杰杰), Yuwei Zhou(周雨威), Jielong Liu(刘捷龙), Sijia Liu(刘思佳), Ling Yang(杨凌), Bin Hou(侯斌), Xiaohua Ma(马晓华), and Yue Hao(郝跃). Chin. Phys. B, 2022, 31(2): 027103.
[7]	High power-added-efficiency AlGaN/GaN HEMTs fabricated by atomic level controlled etching Xinchuang Zhang(张新创), Bin Hou(侯斌), Fuchun Jia(贾富春), Hao Lu(芦浩), Xuerui Niu(牛雪锐), Mei Wu(武玫), Meng Zhang(张濛), Jiale Du(杜佳乐), Ling Yang(杨凌), Xiaohua Ma(马晓华), and Yue Hao(郝跃). Chin. Phys. B, 2022, 31(2): 027301.
[8]	Normally-off AlGaN/GaN heterojunction field-effect transistors with in-situ AlN gate insulator Taofei Pu(蒲涛飞), Shuqiang Liu(刘树强), Xiaobo Li(李小波), Ting-Ting Wang(王婷婷), Jiyao Du(都继瑶), Liuan Li(李柳暗), Liang He(何亮), Xinke Liu(刘新科), and Jin-Ping Ao(敖金平). Chin. Phys. B, 2022, 31(12): 127701.
[9]	Fluorine-plasma treated AlGaN/GaN high electronic mobility transistors under off-state overdrive stress Dongyan Zhao(赵东艳), Yubo Wang(王于波), Yanning Chen(陈燕宁), Jin Shao(邵瑾), Zhen Fu(付振), Fang Liu(刘芳), Yanrong Cao(曹艳荣), Faqiang Zhao(赵法强), Mingchen Zhong(钟明琛), Yasong Zhang(张亚松), Maodan Ma(马毛旦), Hanghang Lv(吕航航), Zhiheng Wang(王志恒), Ling Lv(吕玲), Xuefeng Zheng(郑雪峰), and Xiaohua Ma(马晓华). Chin. Phys. B, 2022, 31(11): 117301.
[10]	A novel Si-rich SiN bilayer passivation with thin-barrier AlGaN/GaN HEMTs for high performance millimeter-wave applications Zhihong Chen(陈治宏), Minhan Mi(宓珉瀚), Jielong Liu(刘捷龙), Pengfei Wang(王鹏飞), Yuwei Zhou(周雨威), Meng Zhang(张濛), Xiaohua Ma(马晓华), and Yue Hao(郝跃). Chin. Phys. B, 2022, 31(11): 117105.
[11]	Device design based on the covalent homocouplingof porphine molecules Minghui Qu(曲明慧), Jiayi He(贺家怡), Kexin Liu(刘可心), Liemao Cao(曹烈茂), Yipeng Zhao(赵宜鹏), Jing Zeng(曾晶), and Guanghui Zhou(周光辉). Chin. Phys. B, 2021, 30(9): 098504.
[12]	High-frequency enhancement-mode millimeterwave AlGaN/GaN HEMT with an f_T/f_max over 100 GHz/200 GHz Sheng Wu(武盛), Minhan Mi(宓珉瀚), Xiaohua Ma(马晓华), Ling Yang(杨凌), Bin Hou(侯斌), and Yue Hao(郝跃). Chin. Phys. B, 2021, 30(8): 087102.
[13]	Epitaxial growth and transport properties of compressively-strained Ba₂IrO₄ films Yun-Qi Zhao(赵蕴琦), Heng Zhang(张衡), Xiang-Bin Cai(蔡祥滨), Wei Guo(郭维), Dian-Xiang Ji(季殿祥), Ting-Ting Zhang(张婷婷), Zheng-Bin Gu(顾正彬), Jian Zhou(周健), Ye Zhu(朱叶), and Yue-Feng Nie(聂越峰). Chin. Phys. B, 2021, 30(8): 087401.
[14]	Transport properties of Tl₂Ba₂CaCu₂O₈ microbridges on a low-angle step substrate Sheng-Hui Zhao(赵生辉), Wang-Hao Tian(田王昊), Xue-Lian Liang(梁雪连), Ze He(何泽), Pei Wang(王培), Lu Ji(季鲁), Ming He(何明), and Hua-Bing Wang(王华兵). Chin. Phys. B, 2021, 30(6): 060308.
[15]	Ferroelectric effect and equivalent polarization charge model of PbZr_0.2Ti_0.8O₃ on AlGaN/GaN MIS-HEMT Yao-Peng Zhao(赵垚澎), Chong Wang(王冲), Xue-Feng Zheng(郑雪峰), Xiao-Hua Ma(马晓华), Ang Li(李昂), Kai Liu(刘凯), Yun-Long He(何云龙), Xiao-Li Lu(陆小力) and Yue Hao(郝跃). Chin. Phys. B, 2021, 30(5): 057302.

No Suggested Reading articles found!

Viewed

Full text

Abstract

Cited

Metrics
Related Articles

Effects of the strain relaxation of an AlGaN barrier layer induced by various cap layers on the transport properties in AlGaN/GaN heterostructures

Cite this article:

Online attention