Semiconductor device and fabrication method therefor

摘要

A semiconductor device of the present invention includes: a p-type silicon substrate having a main surface; a trench formed in an element isolation region on the main surface of the p-type silicon substrate; an inner wall oxide film formed on an inner wall of the trench; an oxynitride layer formed on a surface of the inner wall oxide film; and an isolation oxide film buried into the trench. On the element isolation region, there is formed a gate electrode with a gate oxide film interposed therebetween.