Effect of Ultraviolet Irradiation on 4H-SiC PiN Diodes Characteristics

In this paper, the effect of ultraviolet (UV) irradiation on the static characteristics of high voltage 4H-SiC PiN is investigated. No significant change is observed in the forward on state characteristic of 4H-SiC PiN diodes before and after ultraviolet light irradiation. However, it is found that the blocking voltage is significantly increased with UV irradiation, which is resulted from the depletion region width extension with the collection of positive charges under the increase of the surface negative charge density. The deep level transient spectroscopy reveals that the UV irradiation induced deep-level defects play a dominant role over the trapped negative charges, and therefore leads to the increase of blocking voltage of 4H-SiC PiN Diodes.