Ultra-thin ambipolar germanium on insulator field effect transistors

As semiconductor technology shifts towards semiconductor-on-insulator, material combinations other than Si/SiO$_{2}$ are becoming more attractive. We will report on the transistor characteristics of ultra-thin germanium layers (less than 100 {\AA}) that have been epitaxially grown on a lattice matched epitaxial high-$\kappa $ crystalline oxide (La$_{0.27}$Y$_{0.73})_{2}$O$_{3}$, in turn grown on (111) silicon substrate. This enables the use of Ge, which has higher electron and hole mobilities than Si. Our back-gated germanium on insulator field effect transistors show good transistor characteristics, especially for the very thin layers (30 {\AA}). The devices exhibit a high I$_{on}$/I$_{off}$ ratio and they can be fully depleted and inverted, enabling both P and N channel operation in the same device. Current-voltage measurements at room and low temperature will be presented and compared with device simulations. Hall effect measurements will be used to characterize the quality of the ultra-thin Ge channels.~