The present invention relates to improved metal-oxide-semiconductor field
effect transistor (MOSFET) devices comprising source and drain (S/D)
regions having slanted upper surfaces with respect to a substrate
surface. Such S/D regions may comprise semiconductor structures that are
epitaxially grown in surface recesses in a semiconductor substrate. The
surface recesses preferable each has a bottom surface that is parallel to
the substrate surface, which is oriented along one of a first set of
equivalent crystal planes, and one or more sidewall surfaces that are
oriented along a second, different set of equivalent crystal planes. The
slanted upper surfaces of the S/D regions function to improve the stress
profile in the channel region as well as to reduce contact resistance of
the MOSFET. Such S/D regions with slanted upper surfaces can be readily
formed by crystallographic etching of the semiconductor substrate,
followed by epitaxial growth of a semiconductor material.