Specific features of the steady-state carrier distribution and holding current in an optically triggered SiC thyristor

A numerical model making it possible to analyze the specific features of the steady-state distribution of carriers and the nature of the holding current for the axially symmetric case typical of optically triggered high-power SiC thyristors has been developed. The planar and axially symmetric models are compared. The relative contributions of the field and diffusion mechanisms of turn-on spread are analyzed. It is demonstrated that the diffusion mechanism of turn-on spread does not noticeably contribute to the steady-state carrier distribution and the field mechanism plays a major role. The data obtained are in satisfactory agreement with the first experimental results for the holding current in optically triggered SiC thyristors.