SILICIDE CAP STRUCTURE AND PROCESS FOR REDUCED STRESS AND IMPROVED GATE SHEET RESISTANCE

摘要

A suicide cap structure and method of fabricating a suicide cap having a low sheet resistance. The method provides a semiconductor substrate and a MOSFET structure comprising a gate insulator on the substrate, an Si-containing gate electrode on the gate insulator layer, and source/drain diffusions. Atop the gate electrode and source/drain diffusions is formed a layer of metal used in forming a silicide region atop the transistor gate electrode and diffusions; an intermediate metal barrier layer formed atop the silicide forming metal layer; and, an oxygen barrier layer formed atop the intermediate metal barrier layer. As a result of annealing the MOSFET structure, resulting formed silicide regions exhibit a lower sheet resistance. As the intermediate metal barrier layer comprises a material exhibiting tensile stress, the oxygen barrier layer may comprise a compressive material for minimizing a total mechanical stress of the cap structure and underlying layers during the applied anneal.