| 摘要 |
A nitriding agent is introduced into selected regions of a semiconductor device. A metal such as, for instance, titanium is immediately deposited over the semiconductor device. A subsequent thermal annealing step induces selective reactions between the titanium and the underlying silicon, thereby resulting in the formation of a layer of titanium silicide within the selected regions, as well as a layer of titanium nitride. The layer of titanium nitride and unreacted portions of the layer of titanium are removed in a subsequent etching step, thereby leaving intact a layer of titanium silicide within the selected regions. A second annealing step converts the silicide into a substantially stoichiometric composition. The introduction of the nitriding agent into the selected regions significantly reduces the agglomeration of titanium during silicide formation, thereby resulting in a more uniform, and thus more conductive, silicide layer. In some embodiments, the introduction of the nitriding agent into the selected regions is supplemented by the formation of a layer of silicon-containing material prior to the second annealing step, while in other embodiments the introduction of the nitriding agent is replaced by the formation of the silicon-containing material prior to the second annealing.
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