Thick Selective CVD Tungsten Plugs in a Salicided Two-Level Metal CMOS Technology

The theoretical benefits of thick tungsten plugs in windows, i.e. increased reliability, reduction in layout area, and its diffusion barrier properties, have been pointed out in the past. However, process integration concerns over contact resistance variations, increased junction leakage, loss of selectivity, oxidation resistance, and adhesion problems of tungsten to selfaligned silicides have resulted in limited acceptance of tungsten plugs in current CMOS technologies.