INSULATED GATE TRANSISTOR INCORPORATING DIODE

摘要

A p-type base layer shaped like a well is formed for each of IGBT cells, and a p⁺-type collector layer and an n⁺-type cathode layer are formed on a surface opposite to a surface on which the p-type base layer is formed so as to be situated just below the p-type base layer. The p-type base layer of each of the IGBT cells includes a flat region including an emitter region and a bottom surface penetrated by a main trench, and first and second side diffusion regions between which the flat region is interposed. The first side diffusion region is situated just above the n⁺-type cathode layer and each of the bottom surfaces of the side diffusion regions forms a parabola-shaped smooth curve in longitudinal section. By replacing the p⁺-type collector layer with the n⁺-type cathode layer, it is possible to apply features of the above structure to a power MOSFET.