Impact of barrier thickness on gate capacitance—modeling and comparative analysis of GaN based MOSHEMTs

A mathematical model is developed predicting the behavior of gate capacitance with the nanoscale variation of barrier thickness in AlN/GaN MOSHEMT and its effect on gate capacitances of AlInN/GaN and AlGaN/GaN MOSHEMTs through TCAD simulations is compared analytically. AlN/GaN and AlInN/GaN MOSHEMTs have an advantage of a significant decrease in gate capacitance up to 108 fF/μm² with an increase in barrier thickness up to 10 nm as compared to conventional AlGaN/GaN MOSHEMT. This decrease in gate capacitance leads to improved RF performance and hence reduced propagation delay.