Semiconductor device and method for forming the same

Abstract

A method for forming a semiconductor device is disclosed. A substrate having a P-type device region and an N-type device region is provided. A doped layer is formed in the P-type device region, wherein an upper portion of the doped layer comprises nitrogen dopants, and a lower portion of the doped layer comprises germanium dopants. A first oxidation process is performed to form a first oxide layer on the doped layer in the P-type device region and a second oxide layer on the N-type device region. A second oxidation process is performed to oxidize the substrate through the first oxide layer and the second oxide layer, thereby forming a first gate oxide layer on the P-type device region of the substrate and a second gate oxide layer on the N-type device region of the substrate, wherein the first gate oxide layer comprises the nitrogen dopants.

Dependencies are inferred from the claim text.