中国物理B ›› 2009, Vol. 18 ›› Issue (4): 1618-1621.doi: 10.1088/1674-1056/18/4/055
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
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)
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.
中图分类号: (Surface double layers, Schottky barriers, and work functions)