A process is described that forms a low resistivity connection between a
tungsten layer and a silicon surface with high adherence of the tungsten
to the silicon. The silicon surface is plasma-cleaned to remove native
oxide. A very thin layer (one or more monolayers) of Si-NH.sub.2 is
formed on the silicon surface, serving as an adhesion layer. A WN.sub.x
layer is formed over the Si-NH.sub.2 layer, using an atomic layer
deposition (ALD) process, to serve as a barrier layer. A thick tungsten
layer is formed over the WN.sub.x layer by CVD. An additional metal layer
(e.g., aluminum) may be formed over the tungsten layer.