Semiconductor device production method and semiconductor device

摘要

A semiconductor device production method according to the present invention includes the steps of: forming a LOCOS oxide film in a surface of a silicon layer by a LOCOS method; forming an impurity region in the silicon layer by introducing an impurity into the silicon layer; and sequentially removing parts of the LOCOS oxide film and the silicon layer to form a trench for isolation of the impurity region after the formation of the LOCOS oxide film and the impurity region.