Three part source/drain region structure for transistor

Abstract

A structure for a field-effect transistor includes a semiconductor body, a first gate structure extending over the semiconductor body, and a second gate structure extending over the semiconductor body. A recess is in the semiconductor body between the first and second gate structures. A three part source/drain region includes a pair of spaced semiconductor spacers in the recess; a first semiconductor layer laterally between the pair of semiconductor spacers; and a second semiconductor layer over the first semiconductor layer. The pair of spaced semiconductor spacers, the first semiconductor layer and the second semiconductor layer may all have different dopant concentrations.