Insitu formation of TiSi2/TiN bi-layer structures using self-aligned nitridation treatment on underlying CVD-TiSi2 layer

摘要

The present invention provides a method of forming a contact structure comprised of: a silicon substrate, a titanium silicide layer, a barrier (i.e., TiN or TiNO), and a metal layer (e.g., Al or W). There are three embodiments of the invention for forming the titanium silicide layer and two embodiments for forming the barrier layer (TiN or TiNO). The first embodiment for forming a TiSix layer comprises three selective deposition steps with varying TiCl4: SiH4 ratios. After the TiSix contact layer is formed a barrier layer and a metal plug layer are formed thereover to form a contact structure. The method comprises forming a barrier layer 140 over the silicide contact layer 126; and forming a metal plug 160 over the TiN barrier layer 140. The metal plug 160 is composed of Al or W.