METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for fabricating a semiconductor device is provided to improve the reliance and features of the semiconductor device by preventing a gate insulating layer from being thinned at side edges of a trench. CONSTITUTION: A first insulating layer(14) is formed on a semiconductor substrate(12) and a photoresist pattern(18) is formed on the first insulating layer(14). A trench(20) is provided by etching the first insulating layer(14) and the semiconductor substrate(12). A second insulating layer(16) is formed on the trench(20) and a third insulating layer is formed on an upper portion of the structure. By using the difference of an oxidation rate between the third insulating layer and the semiconductor substrate(12), the semiconductor substrate(12) exposed between the first and third insulating layers is oxidized. Then, a gate insulating layer(24) is formed on an upper portion of the structure and a gate electrode(26) is formed on the gate insulating layer.