Ultrahigh Vacuum Chemical Vapor Deposition of Doped and Intrinsic Si[sub 1−x]C[sub x] Epitaxy from Disilane, Trimethylsilane, and Phosphine

Epitaxial alloys grown in recessed source/drain junctions of n-channel MOSFETs are of interest to induce uniaxial tensile strain in the channel for electron mobility enhancement. In this work, we have studied chemical vapor deposition of intrinsic and heavily phosphorus-doped epitaxial layers on silicon using disilane, trimethylsilane, phosphine, and hydrogen as the gaseous precursors. The results show that phosphorus segregation to the growth surface can be fully suppressed by growing the layers at or below . The best films were obtained at this temperature yielding a growth rate of 4 nm/min. A maximum phosphorus concentration of was obtained with a minimum resistivity of and a substitutional carbon concentration of 1.0%.