中国物理B ›› 2014, Vol. 23 ›› Issue (2): 28101-028101.doi: 10.1088/1674-1056/23/2/028101

• INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY • 上一篇    下一篇

Occurrence and elimination of in-plane misoriented crystals in AlN epilayers on sapphire via pre-treatment control

王虎a, 熊晖a, 吴志浩a, 余晨辉a b, 田玉a, 戴江南a, 方妍妍a, 张健宝a, 陈长清a   

  1. a Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China;
    b Jiangsu Key Laboratory of Application Specific Integrated Circuit Design, Nantong University, Nantong 226019, China
  • 收稿日期:2013-04-03 修回日期:2013-07-08 出版日期:2013-12-12 发布日期:2013-12-12
  • 基金资助:
    Project supported by the National Basic Research Program of China (Grant Nos. 2010CB923204 and 2012CB619302), the National Natural Science Foundation of China (Grant Nos. 60976042, 60906023, 61006046, 51002058, and 11104150), and the Major Program of the National Natural Science Foundation of China (Grant No. 10990100).

Occurrence and elimination of in-plane misoriented crystals in AlN epilayers on sapphire via pre-treatment control

Wang Hu (王虎)a, Xiong Hui (熊晖)a, Wu Zhi-Hao (吴志浩)a, Yu Chen-Hui (余晨辉)a b, Tian Yu (田玉)a, Dai Jiang-Nan (戴江南)a, Fang Yan-Yan (方妍妍)a, Zhang Jian-Bao (张健宝)a, Chen Chang-Qing (陈长清)a   

  1. a Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, China;
    b Jiangsu Key Laboratory of Application Specific Integrated Circuit Design, Nantong University, Nantong 226019, China
  • Received:2013-04-03 Revised:2013-07-08 Online:2013-12-12 Published:2013-12-12
  • Contact: Fang Yan-Yan E-mail:yanyan.fang@mail.hust.edu.cn
  • About author:81.05.Ea; 68.55.A-; 81.15.Gh
  • Supported by:
    Project supported by the National Basic Research Program of China (Grant Nos. 2010CB923204 and 2012CB619302), the National Natural Science Foundation of China (Grant Nos. 60976042, 60906023, 61006046, 51002058, and 11104150), and the Major Program of the National Natural Science Foundation of China (Grant No. 10990100).

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摘要： AlN epilayers are grown directly on sapphire (0001) substrates each of which has a low temperature AlN nucleation layer. The effects of pretreatments of sapphire substrates, including exposures to NH3/H2 and to H2 only ambients at different temperatures, before the growth of AlN epilayers is investigated. In-plane misoriented crystals occur in N-polar AlN epilayers each with pretreatment in a H2 only ambient, and are characterized by six 60°-apart peaks with splits in each peak in (1012) phi scan and two sets of hexagonal diffraction patterns taken along the [0001] zone axis in electron diffraction. These misoriented crystals can be eliminated in AlN epilayers by the pretreatment of sapphire substrates in the NH3/H2 ambient. AlN epilayers by the pretreatment of sapphire substrates in the NH3/H2 ambient are Al-polar. Our results show the pretreatments and the nucleation layers are responsible for the polarities of the AlN epilayers. We ascribe these results to the different strain relaxation mechanisms induced by the lattice mismatch of AlN and sapphire.

关键词: AlN, misoriented, polar, nitridation

Abstract: AlN epilayers are grown directly on sapphire (0001) substrates each of which has a low temperature AlN nucleation layer. The effects of pretreatments of sapphire substrates, including exposures to NH3/H2 and to H2 only ambients at different temperatures, before the growth of AlN epilayers is investigated. In-plane misoriented crystals occur in N-polar AlN epilayers each with pretreatment in a H2 only ambient, and are characterized by six 60°-apart peaks with splits in each peak in (1012) phi scan and two sets of hexagonal diffraction patterns taken along the [0001] zone axis in electron diffraction. These misoriented crystals can be eliminated in AlN epilayers by the pretreatment of sapphire substrates in the NH3/H2 ambient. AlN epilayers by the pretreatment of sapphire substrates in the NH3/H2 ambient are Al-polar. Our results show the pretreatments and the nucleation layers are responsible for the polarities of the AlN epilayers. We ascribe these results to the different strain relaxation mechanisms induced by the lattice mismatch of AlN and sapphire.

Key words: AlN, misoriented, polar, nitridation

中图分类号:  (III-V semiconductors)

  • 81.05.Ea
68.55.A- (Nucleation and growth) 81.15.Gh (Chemical vapor deposition (including plasma-enhanced CVD, MOCVD, ALD, etc.))