Method of fabricating a buried contact structure with WSix sidewall spacers

摘要

A method of forming WSix sidewall spacers as an etching stop in the fabrication process of a buried contact. After a gate dielectric layer and a first conducting layer are formed over a substrate, an opening is formed by etching through the gate dielectric layer and first conducting layer. WSix sidewall spacers are thereafter formed on the sidewalls of the opening. Then, a second conducting layer is deposited onto the overall surface as well as being connected to the substrate via the opening. When the second and first conducting layers are patterned and etched to form a gate electrode and an interconnect layer, the WSix acts as the etching stop to prevent the formation of ditches in the substrate.