METHOD FOR FORMING GATE OXIDE LAYER OF SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for forming a gate oxide layer of a semiconductor device is provided to form a gate insulating layer for preventing degradation of a gate oxide layer. CONSTITUTION: A method for forming a gate oxide layer of a semiconductor device comprises the following steps. A pad oxide layer and a nitride layer are formed on a surface of a semiconductor substrate(21). A trench is formed by etching the nitride layer, the oxide layer and the semiconductor substrate. An oxide layer is formed on a bottom face and a side face of the trench and it is annealed by using a gas containing nitrogen. A trench cap layer(27) is formed on a front face including the trench. The trench cap layer is flattened and the nitride layer is removed. A photoresist layer is applied and formed thereon and the photoresist remains only an active area by patterning selectively it. An edge portion of an upper portion of the trench is etched. The photoresist layer is removed and a gate oxide layer and a gate poly layer are formed on the front face.