Abstract: In the process of manufacturing integrated circuits, the steps of forming a layer of polysilicon, in which a dopant will be implanted, over an oxide mask having suitable windows to define zones of one conductivity type to be formed in a substrate of another conductivity type, driving the dopant from the polysilicon layer into the substrate to form the zones in the substrate, oxidizing the polysilicon layer so that the oxidized polysilicon layer and the mask become an integral layer, and then removing the integrated oxide layer. Thereafter, other layers may be formed on the substrate.