High Performance 400 °C p + /n Ge Junctions Using Cryogenic Boron Implantation

We report high performance Ge p + /n junctions using a single, cryogenic (-100 °C) boron ion implantation process. High activation>4 × 10 20 cm -3 results in specific contact resistivity of 1.7 × 10 -8 Ω-cm 2 on p + -Ge, which is close to ITRS 15 nm specification (1 × 10 -8 Ω-cm 2 ) and nearly 4.5× lower than the state of the art (8 × 10 -8 Ω-cm 2 ). Cryogenic implantation is shown to enable solid-phase epitaxial regrowth and lower junction depth through amorphization of the surface Ge layer. These improvements in Ge p + /n junctions can pave the way for future high mobility Ge p-MOSFETs.