Structural Optimization of 4H-SiC BJT for Ultraviolet Detection with High Optical Gain

The 4H-SiC n-p-n BJT for ultraviolet detection with high optical gain is proposed and optimized in this paper. The effect of structural parameters of 4H-SiC phototransistor on the performance of the detectors is simulated and the effect mechanism is analyzed. The simulation results show that the 4H-SiC phototransistors detect UV light with a response wavelength below 380 nm. It is suggested that the base parameters are important to the responsivity of the 4H-SiC BJT. With optimized parameters the 4H-SiC UV phototransistor exhibits peak responsivity as high as 4617 A/W corresponding to a quantum gain of 2.2×105 under the bias voltage of 5 V.