a polysilicon layer is formed on a dielectric layer positioned on a substrate . then , the polysilicon layer is doped with first type dopants and second type dopants . portions of the polysilicon layer and the dielectric layer are removed down to the surface of the substrate , so as to define at least a high resistance region and a low resistance region on the remainder of the polysilicon layer . finally , a salicide layer is formed on the portions of the polysilicon layer within the low resistance region .