Strained silicon PMOS having silicon germanium source/drain extensions and method for its fabrication

摘要

A strained silicon p-type MOSFET utilizes a strained silicon channel region formed on a silicon germanium substrate. Silicon germanium regions are formed to the silicon germanium layer adjacent to ends of the strained silicon channel region, and shallow source and drain extensions are implanted in the silicon germanium material. The shallow source and drain extensions do not extend into the strained silicon channel region. By forming the source and drain extensions in silicon germanium material rather than in silicon, source and drain extension distortions caused by the enhanced diffusion rate of boron in silicon are avoided.