Suppression of current collapse in AlGaN/GaN MISHFET with carbon- doped GaN/undoped GaN multi-layered buffer structure

We present a new semi-insulating carbon-doped GaN/undoped GaN multi-layered buffer structure for AlGaN/GaN heterojunction field effect transistors, which drastically suppresses current collapse in GaN MISHFET with improving the on-current performance of the device but without degrading the breakdown characteristic. It is believed that spatial compensation between the multi-layered GaN layers not only makes the multi-layered buffer layer very highly resistive, but also prevents the electrons from the 2DEG channel from being captured into deep traps in the buffer layer, which maintains high-high breakdown characteristic and leads to great suppression of current collapse in AlGaN/GaN-based transistors, respectively.