n-MOSFET With Silicon Carbon Source/Drain for Enhancement of Carrier Transport

A novel strained-silicon (Si) n-MOSFET with 50-nm gate length is reported. The strained n-MOSFET features silicon-carbon (Si1-yCy) source and drain (S/D) regions formed by a Si recess etch and a selective epitaxy of Si1-yCyin the S/D regions. The carbon mole fraction incorporated is 0.013. Lattice mismatch of ~0.56% between Si0.987C0.013and Si results in lateral tensile strain and vertical compressive strain in the Si channel region, both contributing to substantial electron-mobility enhancement. The conduction-band offset DeltaEcbetween the Si0.987C0.013source and the strained Si channel could also contribute to an increased electron injection velocity nuinjfrom the source. Implementation of the Si0.987C0.013S/D regions for n-MOSFET provides significant drive current IDsatenhancement of up to 50% at a gate length of 50 nm