Raised source drain mosfet with amorphous notched gate cap layer with notch sidewalls passivated and filled with dielectric plug

Abstract

A method is provided for forming an SOI MOSFET device with a silicon layer formed on a dielectric layer with a gate electrode stack, with sidewall spacers on sidewalls of the gate electrode stack and raised source/drain regions formed on the surface of the silicon layer. The gate electrode stack comprises a gate electrode formed of polysilicon over a gate dielectric layer formed on the surface of the silicon layer. A thin amorphous silicon cap layer is formed in the top surface of the gate electrode by implanting dopant into the surface thereof. A notch is etched into the periphery of the cap layer. A plug of dielectric material is formed in the notch. The sidewalls of the gate electrode are covered by the sidewall spacers which cover a portion of the plug for the purpose of eliminating the exposure of the gate polysilicon so that formation of spurious epitaxial growth during the formation of raised source/drain regions is avoided.