A method and a layered heterostructure for forming high mobility Ge
channel field effect transistors is described incorporating a plurality
of semiconductor layers on a semiconductor substrate, and a channel
structure of a compressively strained epitaxial Ge layer having a higher
barrier or a deeper confining quantum well and having extremely high hole
mobility for complementary MODFETs and MOSFETs. The invention overcomes
the problem of a limited hole mobility due to alloy scattering for a
p-channel device with only a single compressively strained SiGe channel
layer. This invention further provides improvements in mobility and
transconductance over deep submicron state-of-the art Si pMOSFETs in
addition to having a broad temperature operation regime from above room
temperature (425 K) down to cryogenic low temperatures (0.4 K) where at
low temperatures even high device performances are achievable.