High germanium content FinFET devices having the same contact material for nFET and pFET devices

摘要

FinFET structures are formed on silicon germanium fins having high germanium content. Silicon germanium source/drain regions formed in fin recesses in nFET regions are provided with arsenic or phosphorus-doped germanium caps. Uniform tensile strain is obtained through the use of ungraded silicon germanium in the n-type source/drain regions. Location of the germanium caps above the fin structure ensures they have no materially negative impact on strain. Boron doped germanium source/drain regions are formed in fin recesses in pFET regions and provide for compressive strain. Contact formation using the same material in both nFET and pFET regions of the same substrate facilitates fabrication.

主权项

1. A method comprising:
obtaining a structure comprising a substrate, a plurality of rows of parallel semiconductor fins on the substrate, the semiconductor fins having the composition Si1-xGex where x is 0.85 or greater, a plurality of parallel gate structures on the substrate and extending across the rows of parallel semiconductor fins, and a plurality of spacers on the parallel gate structures, the structure having an nFET region and a pFET region; forming recesses within the semiconductor fins in the nFET and pFET regions; epitaxially growing n-doped silicon germanium source/drain regions in the recesses within the nFET region; depositing n-doped cap layers of substantially pure germanium on the n-doped silicon germanium source/drain regions such that the n-doped cap layers extend above the recesses; epitaxially growing p-doped source/drain regions of substantially pure germanium in the recesses within the pFET region, and forming a metal contact layer directly on the n-doped, substantially pure germanium cap layers and the p-doped, substantially pure germanium source/drain regions.