Comparing electrical performance of GaN trench-gate MOSFETs with a-plane (11(2)over-bar0) and m-plane (1(1)over-bar00) sidewall channels

GaN trench-gate MOSFETs with m- and a-plane-oriented sidewall channels were fabricated and characterized. The trench-gate MOSFET performance depended strongly on the sidewall-MOS-channel plane orientation. The m-plane-oriented MOS channel devices demonstrated higher channel mobility, higher current density, lower sub-threshold slope, and lower hysteresis with similar threshold voltage and on-off ratio compared to a-plane MOS channel devices. These results indicate that orienting trench-gate MOSFET toward the m-plane would allow for better on-state characteristics while maintaining similar off-state characteristics. (C) 2016 The Japan Society of Applied Physics