AlGaN/GaN肖特基结参数分析与电流运输机理研究

Analysis of structure parameters and current conduction mechanisms of AlGaN/GaN Schottky contacts

通过对AlGaN/GaN HEMT器件肖特基栅电流输运机理的研究,在变温下采用I-V法对AlGaN/GaN上的Ni/Au肖特基势垒高度和理想因子进行了计算.通过对不同电流机理的分立研究,得到了更为准确的势垒高度值b.通过分析温度在300—550K之间肖特基反向泄漏电流的特性,得出结论:AlGaN材料的表面漏电不是HEMT器件反向泄漏电流的主要来源.

An investigation on the current conduction mechanisms of AlGaN/GaN Schottky contacts is presented in this paper. The ideality factor and the barrier height of Schottky contact on AlGaN/GaN heterostructure are calculated by I-V measurement in a wide temperature range. By subtraction of generation-recombination, tunneling and leakage currents from the total current, the ＂pure＂ Schottky barrier height can be evaluated with higher physical relevance. After analyzing the variational rules of Schottky contact characteristics on A1GaN/GaN heterostructure at 300--550 K, it is concluded that surface leakage current plays an insignificant role in producing the gate leakage current of AlGaN/GaN HEMT.