Patent ID: 7994591
Filing Date: 2011-08-09
Classification: H01L

Abstract:
1. A semiconductor device comprising: a gate structure which includes a silicon oxynitride (SiON) layer on a semiconductor substrate, a first hafnium silicon oxynitride (HfSiON) layer on the silicon oxynitride (SiON) layer, a second hafnium silicon oxynitride (HfSiON) layer on the first hafnium silicon oxynitride (HfSiON) layer, a polysilicon layer on the hafnium silicon oxynitride (HfSiON) layer, and a silicide layer on the polysilicon layer, the second hafnium silicon oxynitride (HfSiON) layer having a hafnium (Hf) content that is less than that of the first hafnium silicon oxynitride (HfSiON) layer; spacers at sidewalls of the gate structure; and source and drain regions disposed at opposite sides of the gate structure.