Patent ID: 7115940

Claim:
A semiconductor device comprising: a semiconductor substrate, having a main surface, in which first and second trenches are formed in said main surface at a distance away from each other; first and second isolation insulating films filling in said first and second trenches; a silicon-containing insulating film, formed on said main surface located between said first isolation insulating film and said second isolation insulating film, having an end portion in a birds beak form which brings into contact with said first isolation insulating film and said second isolation insulating film, respectively, having a first top surface; a silicon film formed on said silicon-containing insulating film, having a thickness exceeding 0 and being less than 50 nm in an intermediate portion between said first isolation insulating film and said second isolation insulating film, and being thinner than said thickness on said end portion; a conductive film, including silicon, located on and connected to said silicon film; and shoulder portions formed in the portions of said semiconductor substrate defining the side faces of said first and second trenches.