Ultrathin epitaxial germanium on crystalline oxide metal-oxide-semiconductor-field-effect transistors

摘要

Ultrathin films of single crystal Ge (100 A or less) have been grown epitaxially on a lattice matched high-k crystalline oxide, lanthanum-yttrium-oxide, in turn grown on Si. Back-gated germanium-on-insulator field-effect transistors have been fabricated and measured from these germanium-on-insulator layers for Ge layers in the 30-600 A range. The best devices exhibit an I_(on)/I_(off) ratio over 10~3 at room temperature and 10~5 at T=77 K. These ultrathin devices can be fully depleted and inverted, enabling both p and n channel operation in the same device.