Damascene gate electrode method for fabricating field effect transistor (fet) device with ion implanted lightly doped extension regions

Abstract

A method for forming a field effect transistor device within a semiconductor product employs a patterned dummy layer first as an ion implantation mask layer when forming a pair of source/drain regions, and then as a mandrel layer for forming a pair of patterned sacrificial layers which define an aperture of linewidth and location corresponding to the patterned dummy layer. A pair of sacrificial spacer layers and a gate electrode are then formed self-aligned within the aperture. The pair of patterned sacrificial layers and the pair of sacrificial spacer layers are then stripped and the gate electrode is employed as a mask for ion implanting forming a pair of lightly doped extension regions partially overlapping the pair of source/drain regions within the semiconductor substrate.