STRAINED MOS DEVICE AND METHODS FOR ITS FABRICATION

摘要

An MOS device having enhanced mobility and a method for its fabrication are provided. The method comprises providing a P-type monocrystalline silicon germanium substrate having a first lattice constant and a channel region at the substrate surface, forming a gate insulator layer on the substrate, forming a gate electrode having a first sidewall and a second sidewall overlying the channel. First and second recesses are etched into the substrate in alignment with the first and the second gate electrode sidewalls, respectively. The recesses are filled by epitaxially growing a layer of embedded monocrystalline semiconductor material characterized by a second lattice constant less than the first lattice constant to impart a tensile strain on the channel region.