Patent ID: 6235595
Filing Date: 2001-05-22
Classification: H01L

Abstract:
A method for fabricating a metal oxide semiconductor, comprising the steps of:providing a substrate;forming a pad oxide layer, a mask layer and a insulator layer in sequence on the substrate;forming an opening in the mask layer and the insulator layer to expose the pad oxide layer by performing a etching;after exposing the pad oxide layer, performing three self-aligned ion implantation processes in sequence forming three doped layers in the substrate by using the insulator and the mask layer as mask, wherein the second and third implantation processes are performed to implant dopants selectively into a portion of substrate so as to avoid ion implantation into a source/drain region, and the depths of the three doped layers are different;removing a portion of pad oxide layer exposed by the opening; andforming a gate on the substrate exposed by the opening.