Strained-Si:C-source/drain NMOSFETs for channel strain enhancement

The carbon was incorporated in biaxial st-Si (stained Si) source/drain NMOSFET for channel strain enhancement. Due to ~52% lattice mismatch between silicon and carbon, the st-Si:C surface channel is under higher strain than that of st-Si, indicating that the carrier mobility can be enhanced significantly by theory. The resistance of st-Si:C with carbon increasing are similar with st-Si, and improved by the strain from underneath relaxed SiGe, as compared with Si:C/Si.