Germanium p-Channel FinFET Fabricated by Aspect Ratio Trapping

We report scaled Ge p-channel FinFETs fabricated on a 300-mm Si wafer using the aspect-ratio-trapping technique. For long-channel devices, a combination of a trap-assisted tunneling and a band-to-band tunneling leakage mechanism is responsible for an elevated bulk current limiting the OFF-state drain current. However, the latter can be mitigated by device design. We report low long-channel subthreshold swing of 76 mV/decade at VDS=-0.5 V, good short-channel effect control, and high transconductance (gm=1.2 mS/μm at VDS=-1 V and 1.05 mS/μm at VDS=-0.5 V for LG=70 nm). The Ge FinFET presented in this paper exhibits the highest gm/SSsat at VDD=1 V reported for nonplanar unstrained Ge p-FETs to date.