高性能AlGaN/GaN HEMT的肖特基特性

Schottky Characteristic of High Performance AlGaN/GaN HEMT

研究了Al GaN/GaN HEMT制备中相关工艺对器件肖特基特性的影响,并对工艺进行了优化。首先研究了表面处理对器件肖特基势垒特性的影响,对不同的表面处理方法进行了比较,发现采用氧等离子体处理,并用V(HF)∶V(H2O)=1∶5溶液清洗刻蚀后的表面,可以有效减小表面态密度,未经处理的样品肖特基接触理想因子为2.6,处理后理想因子减小到1.8。对Si N钝化膜的折射率与肖特基特性的关系进行了研究,发现Si N钝化膜的折射率为2.3～2.4时,钝化对肖特基特性的影响较小,但反向泄漏电流较大。

The effects of several related technologies on schottky characteristic of AlGaN/GaN HEMTs were investigated, and the technologies were optimized. The effects of surface treatment on the schottky characteristic were investigated, the different surface treatment methods were compared. It is found that the density of surface states is reduced effectively by using O2 plasma etching the surface of AlGaN and cleaning the surface with the solution of V（HF） ： V（H2 O） = 1 ： 5. The ideal factor reduces from 2.6 to 1.8 comparing with the sample without surface treatment before schottky metals are deposited. The relationship between the refractive index of SiN passivation film and the schottky characteristic was investigated, indicating that the effect of passivation on schottky characteristic is less at refractive index of 2.3 - 2.4, but the reverse leakage current is still higher.