METHOD FOR FABRICATING ISOLATION LAYER IN SEMICONDUCTOR DEVICE

摘要

A method for forming an element isolation layer of a semiconductor device is provided to improve integration of the semiconductor device by selectively reinforcing the thickness of a lateral oxidation layer in a trench of a peripheral circuit region only. A trench(22A,22B) is formed in a cell region and a peripheral circuit region of a substrate(21). A first lateral insulating layer(25A) is formed in a lateral side of the trench of the peripheral circuit region. A second lateral insulating layer is formed in front of the trench of the peripheral circuit region including the first lateral insulating layer. The second lateral insulating region is formed in front of the trench of the cell region. An insulating layer is reclaimed in the trench of the cell region and the peripheral circuit region.