FABRICATION OF SEMICONDUCTOR DEVICE

PURPOSE: To suppress erroneous function of a split gate type flush memory at the time of writing information. CONSTITUTION: The method for fabricating a semiconductor device comprises a step for forming a first gate insulation film 12 and a polysilicon layer 13 sequentially on a semiconductor substrate 11 and a selective oxide film 14 on the polysilicon layer, a step for removing the polysilicon layer by etching and forming a floating gate 15, a step for depositing a second gate insulation film 16 on the entire surface by low pressure CVD under high temperature and forming a control gate selectively from the upper part to the side part of the floating gate 14, and a step for implanting impurities into the semiconductor substrate 11 using the floating gate 15 and the control gate as a mask thus forming a source-drain region layer.