High voltage normally-off extend p-GaN gate with thin AlGaN barrier layer and AlGaN buffer transistor

This study investigated a normally-off p-GaN/AlGaN/GaN high electron mobility transistor with the extended p-GaN. The optimized recess depth in the AlGaN barrier under the extended region of p-GaN provides improved device characteristics. The influences of recess depth in the AlGaN barrier and the extended length of the p-GaN extension on the threshold voltage (V_TH), the maximum drain current (I_D,MAX), and breakdown voltage were simulated and studied. The proposed transistor with a 1-μm p-GaN extension and 2-nm recess depth in AlGaN barrier shows improvement on V_TH and I_D,MAX without degrading the breakdown voltage compared with the device without p-GaN extension. Graphic abstract: The optimized recess depth (T_R) in the AlGaN barrier under the extended region of p-GaN provides improved device characteristics. [Figure not available: see fulltext.]