The fabrication process of a W-clad layer on p(+)-Si by using chemical vapor deposition is described. X-ray photoelectron spectroscopy and secondary ion mass spectroscopy are used to show that interfacial fluorine causes high contact resistance and weak adhesion of W to the p(+)-Si. A three-step process is shown to reduce the interfacial fluorine, thereby obtaining low contact resistance : Si reduction of WF6, SiH4 reduction of WF6, and in situ annealing at 550 degrees C. This fabrication process gives a low contact resistivity of 2 x 10(-7) Omega cm(2) on a heavily doped p(+)-Si. This technique was used to form a W-clad layer on the p(+)-Si active layer of a p-metal oxide semiconductor field effect transistor on a separation by implanted oxygen substrate.