High percentage silicon germanium alloy fin formation

摘要

A layer of a silicon germanium alloy containing 30 atomic percent or greater germanium and containing substitutional carbon is grown on a surface of a semiconductor layer. The presence of the substitutional carbon in the layer of silicon germanium alloy compensates the strain of the silicon germanium alloy, and suppresses defect formation. Placeholder semiconductor fins are then formed to a desired dimension within the layer of silicon germanium alloy and the semiconductor layer. The placeholder semiconductor fins will relax for the most part, while maintaining strain in a lengthwise direction. An anneal is then performed which may either remove the substitutional carbon from each placeholder semiconductor fin or move the substitutional carbon into interstitial sites within the lattice of the silicon germanium alloy. Free-standing permanent semiconductor fins containing 30 atomic percent or greater germanium, and strain in the lengthwise direction are provided.

主权项

1. A method of forming a semiconductor structure comprising:
forming at least one placeholder semiconductor fin on a surface of a substrate, wherein said at least one placeholder semiconductor fin comprises, from bottom to top, a semiconductor material portion and a silicon germanium alloy portion, said silicon germanium alloy portion contains 30 atomic percent or greater germanium, a first content of substitutional carbon and a strain in a lengthwise direction of said at least one placeholder semiconductor fin; and annealing said at least one placeholder semiconductor fin, wherein said annealing converts said at least one placeholder semiconductor fin into at least one permanent semiconductor fin comprises, for bottom to top, said semiconductor material portion and a silicon germanium alloy portion, said silicon germanium alloy portion of said at least one permanent semiconductor fin contains 30 atomic percent or greater germanium, a second content of substitutional carbon and a strain in a lengthwise direction of said at least one permanent semiconductor fin, wherein said second content of substitutional carbon is less than said first content of substitutional carbon.