Reduction of Current Collapse in GaN (MIS)-HEMTs Using Dual Material Gate

GaN high electron-mobility transistors suffer from various defects or trap states present either in AlGaN barrier or GaN buffer layer. This work presents a different approach to reducing the current-collapse effects in GaN-based transistors by using a dual material gate technology, whereby two different materials having different work functions are merged together to form a single gate, resulting in an improvement of current collapse of around 50%. The current transport efficiency also improves, thus offering improved transconductance. The presence of two gate materials of different work-function modifies the peak electric-field at the drain end, reducing current-collapse and dynamic-Rds,ON degradation.