Tungsten-On-Conducting Nitride Composite Films
Original Publication Date: 1988-Aug-01
Included in the Prior Art Database: 2005-Feb-15
A composite tungsten on a conducting nitride film, such as titanium nitride, zirconium nitride, etc., on doped polysilicon or other substrates, improves tungsten adhesion dramatically, as well as prevents tungsten silicide formation which would increase the resistivity of the film. Tungsten films, whether prepared by magnetron sputtering, electron beam evaporation or low pressure chemical vapor deposition, exhibit high stress. Various parameters can be fine-tuned to lower the stress in each deposition technique, creating a small window at which films will not peel after 800-1000oC post anneal. Reproducing these conditions is very difficult especially when depositing the tungsten films on doped polysilicon. Adhesion on doped polysilicon is worse than on intrinsic polysilicon, single crystal silicon or silicon dioxide.