Epitaxial silicon and germanium on buried insulator heterostructures and devices

Future microelectronics will be based upon silicon or germanium-on-insulator technologies and will require an ultrathin $\text{(<10\hspace{0.5em}}\mathrm{nm}\mathrm{),}$ flat silicon or germanium device layer to reside upon an insulating oxide grown on a silicon wafer. The most convenient means of accomplishing this is by epitaxially growing the entire structure on a silicon substrate. This requires a high quality crystalline oxide and the ability to epitaxially grow two dimensional, single crystal films of silicon or germanium on top of this oxide. We describe a method based upon molecular beam epitaxy and solid-phase epitaxy to make such structures and demonstrate working field-effect transistors on germanium-on-insulator layers.