METHOD FOR SIMPLIFYING GATE OXIDE PROCESS OF SEMICONDUCTOR DEVICE HAVING TRENCH ISOLATION

摘要

PURPOSE: A method for forming a gate oxide of a semiconductor device having a trench isolation is provided to simplify the process and reduce the fabricating cost. CONSTITUTION: A pad oxide(102) and a silicon nitride film(103) are formed on a semiconductor substrate(100) in turn. A trench etching mask(104) is formed by patterning the silicon nitride film and the pad oxide. A trench(106) is formed by etching the semiconductor substrate using the trench etching mask. A trench isolation(108a) is formed by filling the trench with a trench isolation film. Impure ion is implanted into the semiconductor substrate of an active region using the pad oxide as a buffer layer, after removing the silicon nitride film with a phosphoric acid strip process. A gate oxide is formed on the active region after the pad oxide is removed. Thus, the process for forming the gate oxide is simplified by using the pad oxide as the buffer layer, instead of forming a gate oxide for ion implantation buffer.