Elastically relaxed free-standing strained-silicon nanomembranes.
Strain plays a critical role in the properties of materials. In silicon and silicon-germanium, strain provides a mechanism for control of both carrier mobility and band offsets. In materials integration, strain is typically tuned through the use of dislocations and elemental composition. We demonstrate a versatile method to control strain by fabricating membranes in which the final strain state is controlled by elastic strain sharing, that is, without the formation of defects. We grow Si/SiGe layers on a substrate from which they can be released, forming nanomembranes. X-ray-diffraction measurements confirm a final strain predicted by elasticity theory. The effectiveness of elastic strain to alter electronic properties is demonstrated by low-temperature longitudinal Hall-effect measurements on a strained-silicon quantum well before and after release. Elastic strain sharing and film transfer offer an intriguing path towards complex, multiple-layer structures in which each layer's properties are controlled elastically, without the introduction of undesirable defects.
Roberts
Michelle M
MM
University of Wisconsin-Madison, Madison, Wisconsin 53711, USA.
Klein
Levente J
LJ
Savage
Donald E
DE
Slinker
Keith A
KA
Friesen
Mark
M
Celler
George
G
Eriksson
Mark A
MA
Lagally
Max G
MG