凹栅槽AlGaN/GaN HEMTs器件退火处理效应

研究了如何减小等离子体干法刻蚀导致的大肖特基漏电.用X射线光电能谱(XPS)分析刻蚀前后的AlGaN表面,发现刻蚀后AlGaN表面出现了N窄位,导致肖特基栅电流偏离热电子散射模型,N空位做为一种缺陷使得肖特基结的隧穿几率增大,反向漏电增大,肖特基势垒降低.介绍了一种AlGaN/GaN HEMTs器件退火处理方法,优化退火条件为400℃,Nz氛围退火10min.退火后,栅金属中的Ni与Ga原子反应从而减少N空穴造成的缺陷,器件肖特基反向漏电减小三个量级,正向开启电压升高,理想因子从3.07降低到了2.08.

Post-Gate Process Annealing Effects of Recessed AlGaN/GaN HEMTs

This paper focuses on how to reduce the gate leakage current caused by plasma dry etching. X-ray photoelectron spectroscopy (XPS) is employed to measure the AIGaN surface before and after etching. N vacancies are introduced, which cause that gate currents are not dominated by the thermal electron emission mechanism. N vacancies enhance the tunneling effect and reduce the Schottky barrier height as n-type doped in the etched AIGaN surface. A post-gate process for AIGaN/GaN HEMTs,annealing at 400℃ in a nitrogen ambient for 10min is introduced. After annealing, Ni atoms of gate metal reacted with Ga atoms of A1GaN ,and N vacancies were reduced. The reverse leakage decreased by three orders of magnitude,the forward turn-on voltage increased and the ideality factor reduced from 3.07 to 2. 08.