中国物理B ›› 2009, Vol. 18 ›› Issue (4): 1618-1621.doi: 10.1088/1674-1056/18/4/055

• • 上一篇    下一篇

Thermal annealing behaviour of Al/Ni/Au multilayer on n-GaN Schottky contacts

刘芳1, 王涛1, 王鹏1, 姚建铨1, 黄森2, 林芳3, 马楠3, 许福军3, 沈波4   

  1. (1)College of Precision Instrument and Opto-Electronics Engineering, Institute of Laser and Optoelectronics, Tianjin University, Key Laboratory of Optoelectric Information Science and Technology of Ministry of Education, Tianjin University, Tianjin 300072,; (2)State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China; (3)State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China; (4)State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijingn 100871, China
  • 收稿日期:2008-09-15 修回日期:2008-11-07 出版日期:2009-04-20 发布日期:2009-04-20

Thermal annealing behaviour of Al/Ni/Au multilayer on n-GaN Schottky contacts

Liu Fang(刘芳)a), Wang Tao(王涛)a), Shen Bo(沈波)b), Huang Sen(黄森)b), Lin Fang(林芳)b), Ma Nan(马楠)b), Xu Fu-Jun(许福军)b), Wang Peng(王鹏)a), and Yao Jian-Quan(姚建铨)a)   

  1. a College of Precision Instrument and Opto-Electronics Engineering, Institute of Laser and Optoelectronics, Tianjin University, Key Laboratory of Optoelectric Information Science and Technology of Ministry of Education, Tianjin University, Tianjin 300072, China; b State Key Laboratory of Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
  • Received:2008-09-15 Revised:2008-11-07 Online:2009-04-20 Published:2009-04-20

摘要: Recently GaN-based high electron mobility transistors (HEMTs) have revealed the superior properties of a high breakdown field and high electron saturation velocity. Reduction of the gate leakage current is one of the key issues to be solved for their further improvement. This paper reports that an Al layer as thin as 3 nm was inserted between the conventional Ni/Au Schottky contact and n-GaN epilayers, and the Schottky behaviour of Al/Ni/Au contact was investigated under various annealing conditions by current--voltage (I--V) measurements. A non-linear fitting method was used to extract the contact parameters from the I--V characteristic curves. Experimental results indicate that reduction of the gate leakage current by as much as four orders of magnitude was successfully recorded by thermal annealing. And high quality Schottky contact with a barrier height of 0.875 eV and the lowest reverse-bias leakage current, respectively, can be obtained under 12 min annealing at 450°C in N2 ambience.

关键词: Schottky contact, barrier height, ideality factor, thermal annealing

Abstract: Recently GaN-based high electron mobility transistors (HEMTs) have revealed the superior properties of a high breakdown field and high electron saturation velocity. Reduction of the gate leakage current is one of the key issues to be solved for their further improvement. This paper reports that an Al layer as thin as 3 nm was inserted between the conventional Ni/Au Schottky contact and n-GaN epilayers, and the Schottky behaviour of Al/Ni/Au contact was investigated under various annealing conditions by current--voltage (I--V) measurements. A non-linear fitting method was used to extract the contact parameters from the I--V characteristic curves. Experimental results indicate that reduction of the gate leakage current by as much as four orders of magnitude was successfully recorded by thermal annealing. And high quality Schottky contact with a barrier height of 0.875 eV and the lowest reverse-bias leakage current, respectively, can be obtained under 12 min annealing at 450°C in N2 ambience.

Key words: Schottky contact, barrier height, ideality factor, thermal annealing

中图分类号:  (Surface double layers, Schottky barriers, and work functions)

  • 73.30.+y
85.30.Tv (Field effect devices) 81.40.Ef (Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization) 85.30.De (Semiconductor-device characterization, design, and modeling)