Enhancement-Mode High Electron Mobility Transistor on SiC Substrate with T-Gate Field Plate for High Power Applications

A normally Off-GaN based High Electron Mobility transistor is simulated using Sentaurus TCAD and demonstrated the DC and BV characteristics of the device. The divergence in the polarization charges from the barrier and buffer interface depletes the inherent 2DEG (Two-Dimensional Electron Gas) channel and makes the device in off-state. A considerable improvement in the breakdown voltage (BV) and transconductance (gm) are reported in this paper. The transconductance shows a flat behavior over a certain range of gate bias and shows a maximum of 158 mS/μm, which is the maximum, reported for a normally-off GaN based HEMT devices along with high power performance. The T-gate field plate effectively distributes the peak electric field at the drain end of the gate edge over the field plate length (LFP). Consequently, the BV of the device above 2 μm LFP shows a significant improvement. The higher transconductance and BV makes this device a suitable candidate for applications in future high power, high frequency applications.