4H-SiC Light Triggered Thyristor with Gradually Doped Thin n-base

A new 4H-SiC light triggered thyristor} (LFF) with gradually doped thin n-base is proposed and studied. In this new structure, the bottom region of the thin n-base is designed gradually doped to modify the electric field in vertical direction. With the existence of the modified electric field, the hole transmission mechanism in thin n-base is changed from only diffusion to the combination of drift and diffusion. As a result, the hole transport efficiency is enhanced. When triggering by 365 nm ultraviolet light, the turn-on delay time of the new LTT can be reduced by approximately 47.85%, compared with conventional LFF with uniformly doped thin n-base. Meanwhile, the breakdown voltage remains higher than 11.5 kV.