Methods of fabricating a semiconductor device on and in a semiconductor
substrate having a first region and a second region are provided. In
accordance with an exemplary embodiment of the invention, a method
comprises forming a first gate stack overlying the first region and a
second gate stack overlying the second region, etching into the substrate
first recesses and second recesses, the first recesses aligned at least
to the first gate stack in the first region, and the second recesses
aligned at least to the second gate stack in the second region,
epitaxially growing a first stress-inducing monocrystalline material in
the first and second recesses, removing the first stress-inducing
monocrystalline material from the first recesses, and epitaxially growing
a second stress-inducing monocrystalline material in the first recesses,
wherein the second stress-inducing monocrystalline material has a
composition different from the first stress-inducing monocrystalline
material.