Mosfet device and method of controlling dopant diffusion and metal contamination in thin polycide gate conductor

摘要

A MOSFET device is formed on a P- doped semiconductor substrate with an N- well formed therein, with a pair of isolation regions formed in the N- well with a gate oxide layer formed above the N- well. An FET device is formed with source and drain regions within the N-well, and a gate electrode formed above the gate oxide layer aligned with the source and drain regions. The gate electrode comprises a stack of layers. A polysilicon layer is formed on the gate oxide layer. A tungsten nitride dopant barrier layer is formed upon the polysilicon layer having a thickness of from about 5 nm to about 20 nm, and a tungsten silicide layer is formed upon the tungsten nitride layer.