Method of manufacturing semiconductor device capable of suppressing impurity concentration reduction in doped channel region arising from formation of gate insulating film

Abstract

A method of manufacturing a semiconductor device is provided that can suppress impurity concentration reduction in a doped channel region arising from formation of a gate insulating film. With a silicon oxide film (20) and a silicon nitride film (21) being formed, p-type impurity ions (231, 232) are implanted in a Y direction from diagonally above. As for an implant angle α of the ion implantation, an implant angle is adopted that satisfies the relationship tan−1(W2/T)<α≦tan−1(W1/T), where W1 is an interval between a first portion (211) and a fourth portion (214) and an interval between a third portion (213) and a sixth portion (216); W2 is an interval between a second portion (212) and a fifth portion (215); T is a total film thickness of the silicon oxide film (20) and the silicon nitride film (21). When the implant angle α is controlled within that range, impurity ions (231, 232) are implanted into a second side surface (10A2) and a fifth side surface (10A5) through a silicon oxide film (13).

Dependencies are inferred from the claim text.