The proximity of the strain induced effect to improve the electron mobility in a silicon-carbon source-drain structure of n-channel metal-oxide- semiconductor field-effect transistors

The source/drain in an n-channel metal-oxide-semiconductor field-effect transistor (nMOSFET) with solid phase epitaxial (SPE) implanted Si:C before the spacer formation is proposed. Compared to the conventional nMOSFET with SPE implanted Si:C after the spacer formation, it brings in proximity to the device channel and shows great improvement of electron mobility via the stronger tensile strain effect. Experimental measurements showed that the electron mobility in the proposed process is increased by 105% over that of the control devices. At a gate length of 40 nm, an increase of more than 67% for the drain current, comparing to those of the conventional Si:C source/drain nMOSFET, has been achieved.