Semiconductor device with a high breakdown voltage and method for its manufacture

摘要

Phosphorus is doped into one of the major surfaces of an n-type silicon semiconductor substrate (10), and boron is doped into the other major surface. Thereafter, the structure is diffused into the surface regions of the substrate at a high temperature and for a long time, so that an n-buffer layer (11) is formed in the first major surface, and a p-base layer (12) is formed in the second major surface. Impurity of n-type is diffused into the p-base layer (12), to form an n-emitter layer (13). Impurity of p-type is diffused into the n-buffer layer (11), to selectively form p-emitter layer (13). Further, n-type impurity is diffused into the n-buffer layer (11), to form n-type anode short layer (15).