Patent ID: 7112486

Claim:
A method for fabricating a semiconductor device with a dual dielectric structure including a first gate dielectric structure and a second gate dielectric structure, comprising the steps of: forming an insulation layer on a substrate; forming a nitride layer on the insulation layer; selectively etching the nitride layer in a predetermined region of the substrate; performing a radical oxidation process to form an oxide layer on the insulation layer and the etched nitride layer; forming a gate conductive layer on the oxide layer; and performing a selective etching process to the gate conductive layer, the oxide layer, the etched nitride layer and the insulation layer, so that the first dielectric structure formed in the predetermined region includes the insulation layer and the oxide layer and the second gate dielectric structure formed in regions other than the predetermined region includes the insulation layer, the etched nitride layer and the oxide layer.