Epitaxial Growth of Highly Sb-Doped Ge on p-Ge (100) for Vertical Transistor Applications

To realize nanostructured vertical Ge transistors, we investigated the formation of Sb-doped Ge layers on p-type Ge (100) substrate by molecular beam epitaxy. The effect of dopant source temperature variations during deposition on the crystallinity and electrical properties of epitaxial Ge layers was discussed in detail. The doping at T dop. : 325-400ºC realizes n-type Ge layers, that indicated by the rectification behavior of the Ge n + /p junction diodes. Moreover, higher T dop. (~400ºC) resulted in current on-off ratio improvement while maintaining the crystallinity at high dopant concentration.