Selective CVD of tungsten for MOS VLSI application

Low pressure selective chemical vapor deposition of W on Si, PtSi, and Al in a hot wall tubular furnace from a WF/sub 6/ source has been investigated. W contacts have been made to phosphorus and boron doped diffusions and the contact resistance has been measured as a function of doping density. CMOS devices with shallow junctions have been fabricated with W contacts. W was found to be a good barrier against Si diffusion into Al. Schottky diodes have been fabricated by selective CVD of W on N type Si, and the technology has been used to fabricate PMOS transistors for latch-up free CMOS. Ion beam induced formation of WSi/sub 2/ by depositing W on Si ion implanting As has been investigated for silicidation of source, drain and gate