Semiconductor device with a trench isolation region and method of manufacturing the same.

摘要

A semiconductor device comprises a semiconductor substrate (11) having a major surface, a trench device isolation region (30) having a trench (16) selectively formed to define at least one island region in the major surface of the semiconductor substrate (11) and a filler (18a) insulatively formed within the trench (16), an elongated gate electrode (20) insulatively formed over a central portion of the island region so that each of its both ends which are opposed to each other in the direction of its length overlaps the trench device isolation region (30), and source and drain regions formed within the island region on the both sides of the gate electrode (20). The surface of the trench device isolation region (30) is formed lower than the major surface of the semiconductor substrate (11). Those portions of the major surface of the semiconductor substrate (11) that are located under the gate electrode (20) at the boundary with the trench device isolation region (30) are rounded, and the radius of curvature of these portions of the major surface of the semiconductor substrate (11) is selected to be not less than 50 nm.