| 摘要 |
A process for forming a metal suicide gate in an FET device, where the suicide is self-forming (that is, formed without the need for a separate metal/silicon reaction step), and no CMP or etchback of the silicon material is required. A first layer of silicon material (polysilicon or amorphous silicon) is formed overlying the gate dielectric; a layer of metal is then formed on the first layer, and a second layer of silicon on the metal layer. A high-temperature (>700° C.) processing step, such as source/drain activation anneal, is subsequently performed; this step is effective to form a silicide layer above the gate dielectric by reaction of the metal with silicon in the first layer. A second high-temperature processing step (such as source/drain silicidation) may be performed which is effective to form a second silicide layer from silicon in the second layer. The thicknesses of the layers are such that in the high-temperature processing, substantially all of the first layer and at least a portion of the second layer are replaced by silicide material. Accordingly, a fully silicided gate structure may be produced.
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