Patent ID: 7157341

Claim:
A method of forming a semiconductor structure, comprising the steps of: providing a semiconductor region; forming a gate stack on top of the semiconductor region, the gate stack including (i) a gate dielectric region on top of the semiconductor region, (ii) a first gate polysilicon region on top of the gate dielectric region, and (iii) a second gate polysilicon region on top of the first gate polysilicon region, the second gate polysilicon region being doped with a type of dopants; and forming on a side wall of the gate stack a diffusion barrier region and a spacer oxide region, wherein the diffusion barrier region is sandwiched between the gate stack and the spacer oxide region, wherein the diffusion barrier region is in direct physical contact with both the first and second gate polysilicon regions, and wherein the diffusion barrier region comprises a material having a property of preventing a diffusion of oxygen-containing materials through the diffusion barrier region.