Patent ID: 6528434
Filing Date: 2003-03-04
Classification: H01L

Abstract:
A method of forming an oxide layer with different thickness on a semiconductor substrate comprising a bare silicon surface, the oxide layer doped using a nitrogen plasma, the silicon surface comprising a first region and a second region, the method comprising:forming a first mask layer on the silicon surface covering the first region and the second region; patterning the first mask layer to form a first hole in the first mask layer over the first region; providing a pulse bias to form a nitrogen plasma environment, a nitrogen ion implantation process being simultaneously performed to implant a predetermined concentration of nitrogen ions to form a doped area of nitrogen ions having a thickness less than 100 angstroms in the silicon surface of the first region through the first hole; removing the first mask layer; and performing an oxidizing process to simultaneously form a first thickness and a second thickness of a silicon oxide layer in the first region and in the second region, respectively; wherein the nitrogen plasma formed in-situ by the pulse bias performs the nitrogen ion implantation in a thin region of the silicon surface so that damage to the silicon surface is reduced to maintain an ideal structure of the silicon oxide.