Current Collapse Suppression in AlGaN/GaN HEMTs Using Silicon Substrate Removal Technique

Abstract

The electrical characteristics and current collapse phenomenon of AlGaN/GaN/Si HEMTs after local Si substrate removal are investigated. Our study shows that removal process has no obvious impact on 2DEG density. However, we observe mitigation of current collapse after Si substrate removal, which is in contrast with a severe current degradation when we gradually increase the negative gate bias at pulse condition on the HEMTs with Si substrate. A physical model which involves strain relaxation and GaN buffer/Si interface defect reduction is employed to explain the electrical behavior.