Design and Simulation of 4H-SiC MESFET Ultraviolet Photodetector with Gain

Abstract

The 4H-SiC ultraviolet detector of the MESFET structure with gain is proposed and simulated in this paper. The Schottky gate of MESFET is transparent or semi-transparent to allow more of the incident UV light to be absorbed in the device. The effect of the doping and thickness of the channel layer on the photocurrent of the 4H-SiC MESFET UV detector is simulated and the effect mechanism is analyzed. The simulation results show that the 4H-SiC MESFET exhibits photocurrent below 380 nm. And only when the channel of the 4H-SiC MESFET is in the open state there will be a gain in the detector. Shorter gate length is beneficial to improve the responsivity and the gain of the 4H-SiC MESFET UV detector. When the gate length is set to 10 μm with the channel thickness of 0.3 μm and channel doping of 1×1017 cm-3, the peak responsivity and the gain are calculated to be 12.9 A/W and 55.6 respectively.