Semiconductor device having contact of Si-Ge combined with cobalt silicide

摘要

The present invention provides a metal contact of SiGe combined with cobalt silicide and cobalt. The contact resistance is greatly lowered due to both the low Schottky Barrier Height of SiGe and the low sheet resistance of cobalt silicide. The cobalt layer can serve as a glue layer and diffusion barrier layer. Thus, no additional glue layer or diffusion barrier layer needs to be formed. Moreover, the metal contact of the present invention can be integrated with a DRAM by a hybrid contact method. Implantation contact is used in pFET regions and diffusion contact is used in nFET regions. This can reduce mask steps and production costs.