Enhancement-mode n-GaN gate p-channel heterostructure field effect transistors based on GaN/AlGaN 2D hole gas

In this letter, E-mode n-GaN gate heterostructure field effect transistors (HFETs) utilizing polarization induced 2D hole gas (2DHG) have been proposed. It is found that the introduction of the n-GaN cap between the GaN channel layer and the gate metal can effectively deplete the 2DHG in the gate region, resulting in E-mode operation. The simulation results indicate that by adjusting the GaN channel thickness and n-GaN cap doping concentration, threshold voltage of the n-GaN gate p-channel HFETs can be more than |−1.5| V without sacrificing the ON-state current and the ON/OFF ratio, which is enabled to overcome the trade-off observed from conventional p-channel devices.