Device Performance Enhancement of AlGaN/GaN MIS-HEMT Using High-k Materials for Surface Passivation and Gate Insulator

• Main Authors: Liao, Jen-Ting, 廖仁廷
• Other Authors: 張翼
• Format: Others
• Language: en_US
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/ryf4vv

碩士 === 國立交通大學 === 影像與生醫光電研究所 === 102 === In recent years, AlGaN/GaN high electron mobility transistors (HEMTs) have been widely studied for high power applications. However their performance and reliability are limited by the gate leakage current and drain current collapse. The utilization of insulator to form metal-insulator-semiconductor (M-I-S) gate structures has shown remarable improvements in reducing gate leakage current. In this study, we developed two kinds of MIS-HEMTs by using CeO2 and Al2O3/AlN dual layer with different plasma powers AlN deposition to compare the electric properties with conventional HEMT. The gate leakage current of CeO2 MOS-HEMTs is suppressed almost four orders of magnitude compared with conventional HEMTs in positive bias region. For Al2O3/AlN, both of MIS-HEMTs can mitigate almost eight orders of gate leakage current. Other DC characteristics such as maximum drain current, threshold voltage and tras-conductance also exhibited good performance in MIS-HEMT. Besides, we obtained good quality of insulator deposition as revealed by the frequency dispersion and hysteresis effect measurement in this study.