中国物理B ›› 2011, Vol. 20 ›› Issue (4): 47105-047105.doi: 10.1088/1674-1056/20/4/047105

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Influence of thermal stress on the characteristic parameters of AlGaN/GaN heterostructure Schottky contacts

陈弘1, 王占国2, 吕元杰3, 林兆军3, 张宇3, 孟令国3, 曹芝芳3, 栾崇彪3   

  1. (1)Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; (2)Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China; (3)School of Physics, Shandong University, Jinan 250100, China
  • 收稿日期:2010-09-11 修回日期:2010-11-17 出版日期:2011-04-15 发布日期:2011-04-15
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 10774090) and the National Basic Research Program of China (Grant No. 2007CB936602).

Influence of thermal stress on the characteristic parameters of AlGaN/GaN heterostructure Schottky contacts

Lü Yuan-Jie(吕元杰)a), Lin Zhao-Jun(林兆军) a)†, Zhang Yu(张宇)a), Meng Ling-Guo(孟令国)a), Cao Zhi-Fang(曹芝芳)a), Luan Chong-Biao(栾崇彪) a), Chen Hong(陈弘)b), and Wang Zhan-Guo(王占国)c)   

  1. a School of Physics, Shandong University, Jinan 250100, China; b Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; c Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
  • Received:2010-09-11 Revised:2010-11-17 Online:2011-04-15 Published:2011-04-15
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 10774090) and the National Basic Research Program of China (Grant No. 2007CB936602).

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摘要： Ni Schottky contacts on AlGaN/GaN heterostructures have been fabricated. The samples are then thermally treated in a furnace with N2 ambient at 600 circC for different times (0.5, 4.5, 10.5, 18, 33, 48 and 72 h). Current-voltage (I-V) and capacitance-voltage (C-V) relationships are measured, and Schrödinger's and Poisson's equations are self-consistently solved to obtain the characteristic parameters related to AlGaN/GaN heterostructure Schottky contacts: the two-dimensional electron gas (2DEG) sheet density, the polarization sheet charge density, the 2DEG distribution in the triangle quantum well and the Schottky barrier height for each thermal stressing time. Most of the above parameters reduce with the increase of stressing time, only the parameter of the average distance of the 2DEG from the AlGaN/GaN interface increases with the increase of thermal stressing time. The changes of the characteristic parameters can be divided into two stages. In the first stage the strain in the AlGaN barrier layer is present. In this stage the characteristic parameters change rapidly compared with those in the second stage in which the AlGaN barrier layer is relaxed and no strain is present.

关键词: AlGaN/GaN heterostructures, thermal stressing, polarization, self-consistently solving Schrö, dinger's and Poisson's equations

Abstract: Ni Schottky contacts on AlGaN/GaN heterostructures have been fabricated. The samples are then thermally treated in a furnace with N2 ambient at 600 $^\circ$C for different times (0.5, 4.5, 10.5, 18, 33, 48 and 72 h). Current-voltage (I–V) and capacitance–voltage (C–V) relationships are measured, and Schrödinger's and Poisson's equations are self-consistently solved to obtain the characteristic parameters related to AlGaN/GaN heterostructure Schottky contacts: the two-dimensional electron gas (2DEG) sheet density, the polarization sheet charge density, the 2DEG distribution in the triangle quantum well and the Schottky barrier height for each thermal stressing time. Most of the above parameters reduce with the increase of stressing time, only the parameter of the average distance of the 2DEG from the AlGaN/GaN interface increases with the increase of thermal stressing time. The changes of the characteristic parameters can be divided into two stages. In the first stage the strain in the AlGaN barrier layer is present. In this stage the characteristic parameters change rapidly compared with those in the second stage in which the AlGaN barrier layer is relaxed and no strain is present.

Key words: AlGaN/GaN heterostructures, thermal stressing, polarization, self-consistently solving Schrödinger's and Poisson's equations

中图分类号:  (III-V semiconductors)

  • 71.55.Eq
73.20.At (Surface states, band structure, electron density of states) 77.22.Gm (Dielectric loss and relaxation)