Semiconductor device and fabrication method thereof

摘要

A semiconductor device fabrication method is provided in which recesses are formed at source/drain positions in the substrate, removable sidewalls are formed on side walls of the recess, and the recesses then are etched to form Sigma shaped recesses. Selective epitaxial growth of substantially un-doped SiGe in the Sigma shaped recesses is performed, and the Sigma shaped recesses close to the surface of the substrate can be protected from epitaxial growth by the removable sidewalls. Epitaxial growth of SiGe doped with a P-type impurity can be performed in the Sigma shaped recesses after removing the sidewalls.

主权项

1. A semiconductor device fabrication method comprising:
providing a substrate on which a gate structure is formed; etching the substrate to form a recess at a source/drain position in the substrate; forming removable sidewalls on side walls of the recess; etching the recess to form a Sigma shaped recess; performing selective epitaxial growth of substantially un-doped SiGe in the Sigma shaped recess; removing the removable sidewalls; performing epitaxial growth of SiGe doped with P-type impurities in the Sigma shaped recess.