Method of making high-voltage hv transistors with drain extension in a cmos process of the dual gate type with silicide

Abstract

In a CMOS process for making dual gate transistors with silicide, high-voltage transistors with drain extensions are produced by first defining on a semiconductor substrate, active areas for low-voltage and high-voltage transistors. A gate oxide layer and a layer of polysilicon is deposited over the substrate, which is masked and etched to produce gates for the transistors. A dielectric layer is deposited to produce spacers to the sides of the transistor gate regions, then a mask partially shields the dielectric layer over the junctions of the high-voltage transistors while the spacers are being formed. Finally, the substrate is doped in the gate and active areas of the high-voltage transistor, and in the gate and active areas of the low-voltage transistor, except those areas that are blocked by the spacers.