STRUCTURE OF SELECTIVE LOW PRESSURE CHEMICALLY VAPOR-DEPOSITED FILMS OF TUNGSTEN.

Tungsten films have been selectively deposited by LPCVD via the reduction of WF//6 by either Si or H//2. Films formed by H//2 reduction can be unlimited in thickness; however, those formed by Si reduction are self-limited in thickness to about 150 angstroms. The effects of deposition parameters such as temperature and WF//6 and H//2 flow rates on the properties of the W films have been investigated. The W films exhibit good contact resistance to N** plus and P** plus Si, and are also found to be excellent diffusion barriers between Al and Si at annealing temperatures up to 450 degree C.