Two-Dimensional Electron Gases in Nanomembrane-based Epitaxial Si/SiGe Heterostructures
ORAL
Abstract
To assess possible improvements in the electronic performance of two-dimensional electron gases (2DEGs) in silicon, SiGe/Si/SiGe heterostructures are grown on fully elastically relaxed single-crystal SiGe nanomembranes fabricated through a strain engineering approach. This procedure eliminates the formation of dislocations in the heterostructure. Top-gated Hall bar devices are fabricated to enable magnetoresistance and Hall effect measurements. Both Shubnikov de Haas oscillations and the quantum Hall effect are observed at low temperatures, demonstrating the formation of high-quality 2DEGs. Values of charge carrier mobility as a function of carrier density extracted from these measurements are at least as high or higher than those obtained from companion measurements made on heterostructures grown on conventional strain graded substrates. In all samples impurity scattering appears to limit the mobility.
*Supported by U.S. Dept. of Defense. The views and conclusions are those of the authors and should not be interpreted as representing the official policies, either expressly or implied, of the U.S. Government. Facilities support: DOE
–