METHOD FOR FORMING ISOLATION LAYER OF SEMICONDUCTOR DEVICES

摘要

PURPOSE: A trench isolation layer formation method is provided to prevent leakage current and degradation of a gate oxide by making roundly the edge portion of the isolation layer. CONSTITUTION: A pad oxide(32) and a nitride layer(33) are sequentially formed on a silicon substrate(31). By first over-etching the nitride layer(33) and the pad oxide(32) using a mask pattern(34), a nonactive region of the substrate(31) is exposed and a groove(35) having rounded slope side walls is formed. By second etching the silicon substrate(31) having the groove(35), a trench(36) is formed, wherein the edge portion of the trench(36) has a rounded slope. Then, an isolation layer(37a) is formed by filling the trench(36) in order to have a step compared to the silicon substrate(31).