The surface of a conductive layer such as a conductive nitride, a conductive silicide, a metal, or metal alloy or compound, is exposed to a dopant gas which provides an n-type or p-type dopant. The dopant gas may be included in a plasma. Semiconductor material, such as silicon, germanium, or their alloys, is deposited directly on the surface which has been exposed to the dopant gas. During and subsequent to deposition, dopant atoms diffuse into the deposited semiconductor, forming a thin heavily doped region and making a good ohmic contact between the semiconductor material and the underlying conductive layer.