METHOD FOR FORMING NICKEL SILICIDE WITH LOW DEFECT DENSITY IN FET DEVICES

摘要

A method and an apparatus are provided in which non-directional and directional metal (e.g. Ni) deposition steps are performed in the same process chamber. A first plasma is formed for removing material from a target; a secondary plasma for increasing ion density in the material is formed in the interior of an annular electrode (e.g. a Ni ring) connected to an RF generator. Material is deposited non-directionally on the substrate in the absence of the secondary plasma and electrical biasing of the substrate, and deposited directionally when the secondary plasma is present and the substrate is electrically biased. Nickel silicide formed from the deposited metal has a lower gate polysilicon sheet resistance and may have a lower density of pipe defects than NiSi formed from metal deposited in a solely directional process, and has a lower source/drain contact resistance than NiSi formed from metal deposited in a solely non-directional process.