Abstract: Described is a process used during the formation of a semiconductor device to produce a doped layer of polycrystalline silicon having a pair of conductivity types using a single mask step. In a first embodiment, a patterned nonoxidizing layer is formed over the layer of polycrystalline silicon thereby leaving protected and exposed poly. The exposed polycrystalline silicon is doped, then oxidized, with the protected poly being free of oxidation. The nonoxidizing layer is stripped, and a blanket implant is performed. The oxidation prevents the previously doped polycrystalline silicon from being counterdoped. The oxidation is then stripped and wafer processing continues. In a second embodiment, a layer of resist is formed over the polycrystalline silicon layer, and the exposed poly is heavily doped with a material having a first conductivity type. The resist is removed, and the surface is blanket doped with a material having a second conductivity type.

Abstract: A process for forming a doped region in a substrate which is in alignment with a circuit member by forming a masking member on a layer, the masking member defining the outline on the circuit member; and etching the layer employing the masking member as a mask to define the circuit member, the etching continuing such that the circuit member includes sloping side faces. Subsequently, a dopant species is implanted into the substrate so as to form the doped region, the dosage and energy of ions implanted being selected such that ions are partially blocked by the portion of the circuit member beneath the sloping side faces thereby providing a more lightly doped and more shallow distribution of implanted species region than in other regions.