STUDY OF TRAPPING EFFECTS IN ALGAN/GAN MOSHEMTS

Abstract

AlGaN/GaN metal oxide semiconductor high electron mobility transistors (MOSHEMTs) are very attractive for high power and high frequency and high temperature applications, with low gate leakage current. However, it is believed that charge trapping at the insulator/AlGaN interface limits the performance of AlGaN/GaN MOSHEMTs. In order to have a deeper understanding of the trapping effects in AlGaN/GaN MOSHEMTs, various methods were employed in this thesis. The effects of SiH4 passivation on HfAlO/AlGaN/GaN MOSHEMTs were investigated using TCAD simulation by fitting I-V simulation to experimental data. Next, the characteristics (eg. trap energy and time constant) of traps under the gate electrode in Al2O3/Al0.25Ga0.75N/GaN MOSHEMTs were investigated using gate stress-induced transient drain current method. In addition, pulsed I-V method together with TCAD simulation fittings were used to investigate the trap behavior under and near the gate electrode of Al2O3/Al0.25Ga0.75N/GaN MOSHEMTs.