Carbon incorporation into substitutional silicon site by carbon cryo ion implantation and metastable recrystallization annealing as stress technique in n-metal-oxide-semiconductor field-effect transistor

Abstract

Since the lattice constant of silicon-carbon (Si:C) is smaller than that of Si, Si:C embedded in the source and drain (e-Si:C S/D) can induce tensile stress in the channel and improve the electron mobility of n-metal-oxide-semiconductor field-effect transistors (nMOSFETs). In this research, C ion cryo implantation and a metastable recrystallization schemes employed to achieve strained Si:C layers with a high substitutionally incorporated carbon concentration ([C]sub) at a high ratio of substitution, and a high doping activation were studied. we proposed the C cryo implantation for reduced implantation damage, the fast recrystallization by nonmelt laser annealing combined with solid phase epitaxy (SPE) annealing that promote Si regrowth in a high-C-concentration region, and the co-incorporation of phosphorus (P). These processes promoted markedly the recrystallization of C densely incorporated in an amorphous Si layer and realized e-Si:C S/D with high-crystallinity of strained Si:C layer while maintaining a high [C]sub at a high ratio of substitution with a high doping activation.