TRENCH ISOLATION LAYER AND MANUFACTURING METHOD THEREOF

摘要

PURPOSE: A trench isolation layer and a method for manufacturing the same are provided to prevent a focusing of electric field from the corner of an isolation layer by rounding the corner. CONSTITUTION: A first oxide(120b) is filled into a trench(116) of a semiconductor substrate(104). The first oxide(120b) is surrounded by a buffer layer(118a). A thermal oxide(114a) is formed at both corner of the trench(116) and adjacent to the buffer layer. The interface between the thermal oxide(114a) and the semiconductor substrate(104) has a rounding shape. Preferably, the semiconductor substrate(104) has an SOI(Silicon On Insulator) structure stacked sequentially a silicon substrate(100), a buried oxide(101) and a silicon layer(102).