Effects of annealing on the performance of 4H-SiC metal–semiconductor–metal ultraviolet photodetectors

4H-SiC-based metal–semiconductor–metal (MSM) photodetectors (PDs) have been designed, fabricated, and characterized, in which nickel Schottky contacts were needed. Current–voltage and spectral responsivity measurements were carried out at room temperature to character the effect of annealing on the performance of the MSM devices. It was found to improve both Schottky barrier height and ideality factors after annealing at appropriate temperature. The chemical component depth profiles of XPS measurement showed nickel silicides were produced at the interface, leading to improvement of the Ni/4H-SiC contacts and the performance of the PDs. The MSM PDs with RTA had a lower dark current (0.45 pA at 5 V bias voltage), a typical responsivity of 0.094 A/W at 20 V and displayed peak response wavelength at 290 nm.