SEMICONDUCTOR SUBSTRATE, FABRICATING METHOD THEREOF, SEMICONDUCTOR DEVICE, AND FABRICATING METHOD THEREOF TO REDUCE DEFECT

摘要

PURPOSE: A semiconductor substrate is provided to reduce or remove a defect of a semiconductor substrate caused by formation of an impurity diffusion region by forming an impurity diffusion layer in the first main surface of the substrate and by forming an impurity region in the second main surface of the substrate. CONSTITUTION: A substrate(1) of the first conductivity type has the first and second main surfaces confronting each other. An impurity diffusion layer(3) of the second conductivity type different from the first conductivity type is formed in the first main surface by diffusion of impurities. An impurity diffusion region of the second conductivity type surrounds a part of the substrate of the first conductivity type two-dimensionally, partially formed in the second main surface by the diffusion of impurities and having a bottom surface reaching the impurity diffusion layer. The portion of the substrate surrounded by the impurity diffusion region is defined as a device formation region.