Semiconductor device and process for producing the sme

A semiconductor device which comprises a semiconductor substrate and an element isolation oxide film having a groove isolation structure formed on the circuit-forming side of the semiconductor substrate, where the substrate has a monotonously convexed shape around the upper edge of the groove of the groove isolation structure;

• the oxide film is oxidized to have a thickness of 5 to 70 nm at the inside wall of the groove at the intermediate level of the groove isolation structure;
• and the semiconductor substrate has a radius of curvature in a range of 3 to 35 nm at the upper edge thereof.