Patent ID: 7687363
Filing Date: 2010-03-30
Classification: H01L

Abstract:
1. A method of manufacturing a semiconductor device, the method comprising the steps of: forming a buffer oxide film on a semiconductor substrate; forming a high-voltage well region in the semiconductor substrate by performing a first ion implantation at a relatively low energy, a second ion implantation at a medium energy, and a third ion implantation at a relatively high energy; forming a pad nitride film on the buffer oxide film; patterning the pad nitride film and the buffer oxide film and forming an isolation layer on the semiconductor substrate; removing the patterned pad nitride film; implanting first dopants into the high-voltage well region, thereby forming a low-voltage well region within the high-voltage well region; forming a gate electrode on the semiconductor substrate; and implanting second dopants into the low-voltage well region using the gate electrode as a mask, thereby forming source/drain regions within the low-voltage well region.