Polysilicon gate salicidation

Abstract

A method of fabricating a substantially completely silicided polysilicon gate electrode in a CMOS process flow. A hard mask material is formed on an integrated circuit substrate, where the integrated circuit substrate includes an unpatterned polysilicon layer that overlies a gate oxide layer, and a well region disposed between isolation structures. Portions of the hard mask material are removed to define gate electrode masks that overlie first portions of the unpatterned polysilicon layer and the gate oxide layer, leaving exposed second portions of the unpatterned polysilicon layer and the gate oxide layer. The integrated circuit substrate is exposed to a dopant that passes through the second portions of the gate oxide layer but does not penetrate the first portions of the gate oxide layer that underlie the gate electrode masks, which defines source drain regions in the well region. The exposed second portions of the unpatterned polysilicon layer are removed to define polysilicon gate electrode precursors under the gate electrode masks. The gate electrode masks are removed from the polysilicon gate electrode precursors, and a metal layer is deposited over the polysilicon gate electrode precursors and the source drain regions. The integrated circuit substrate is annealed to substantially completely consume the polysilicon gate electrode precursors and form silicide gate electrodes from the polysilicon gate electrode precursors and the overlying metal layer, by which silicide contacts in the source drain regions are also formed.