Method of manufacturing a semiconductor device

Abstract

A method of manufacturing a semiconductor device includes the steps of forming memory cell sections in a nonvolatile semiconductor memory device which has the memory cell sections and peripheral circuit transistor sections formed on a semiconductor substrate, coating a stacked region of the memory cell sections and a top surface of the peripheral circuit transistor sections with an oxidation-resistant layer, and forming an oxide layer over the surface of the semiconductor substrate by thermal oxidation. The peripheral circuit transistor gate oxide layer is suitably oxidized to have sufficient dielectric strength while preventing the interlayer insulating layer between the control gate edge and the floating gate edge of a memory cell from being oxidized more than necessary.