Design of high voltage 4H-SiC superjunction Schottky rectifiers

This paper presents a novel Schottky rectifier structure based on the superjunction approach, which is utilizes 2- and 3D field shaping to increase the avalanche breakdown voltage. Device forward and blocking characteristics are analyzed with numerical simulations and compared with conventional 4H-SiC Schottky rectifiers. Optimal design tradeoffs between breakdown voltage and specific on-resistance are obtained for high voltage 4H-SiC superjunction Schottky rectifiers. The results show that the new structure can provide a 20 × lower R_on,sp than conventional Schottky rectifier for 6kV device. In addition, device termination and possible fabrication steps for the superjunction devices are also presented.