United Microelectronics Corp.

Wen-Yi Shieh

Li-Yeat Chen

Haber Chen

Several processes for forming semiconductor gate structures having treated titanium silicide layers are disclosed. There are at least three methods been provided for the present invention and a summarized general procedure of all the methods comprises the following steps: The first step is to provide a silicon substrate having a gate oxide layer formed on top the silicon substrate, and forming a polysilicon layer over the gate oxide layer, followed by the formation of a TiN layer over the polysilicon layer. A treated titanium silicide layer is then formed on top of the TiN layer. Sequentially, an anti-reflection (SiON) film is deposited on top of the treated titanium silicide layer with a capping layer formed over the anti-reflection film. Finally, patterning and etching the above layers to expose a portion of the gate oxide layer and to form a gate electrode, where the final gate structure is rounded up by a rapid thermal process (RTP). The step of forming a treated titanium silicide layer further comprises one of the following: impurity doping by implantation, sputtering with nitrogen gas, and using TiSi.sub.x M.sub.y target. As a result of this, a wider thermal-stress window has been achieved by the present invention.

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Hsin-Chu, Taiwan

Wen-Yi Shieh