Patent ID: 7427533
Filing Date: 2008-09-23
Classification: H01L

Abstract:
1. A method of forming a semiconductor device, the method comprising: patterning a buffer insulating layer, a buffer silicon layer and a hard mask layer which are sequentially stacked on a substrate, to expose a predetermined region of the substrate; etching the exposed substrate to form a trench defining an active region; recessing a side surface of the patterned buffer insulating layer to form an undercut region; performing a first oxidation process over the substrate to form a first oxide layer; removing the first oxide layer; performing a second oxidation process over the substrate to form a second oxide layer that fills the undercut region; forming a device isolation layer filling the trench; and removing the patterned hard mask, the patterned buffer silicon layer and the patterned buffer insulating layer in sequence to expose the active region.