Semiconductor device and process

A process for manufacturing a semiconductor device includes the formation of tungsten contact plugs suitable for very small geometry devices. As part of the process a tungsten barrier layer is deposited into vias and covering the walls of the vias by a process of ionized metal plasma deposition. The tungsten layer deposited in this manner provides a barrier layer, adhesion layer, and nucleation layer for the subsequent chemical vapor deposition of tungsten contact plug material. Together the two layers of tungsten form contact plugs having a low resistance even when used in the fabrication of very small geometry devices.