Ge n-channel FinFET with optimized gate stack and contacts

Whilst high performance p-channel Ge MOSFETs have been demonstrated [1–4], Ge n-channel MOSFET drive current has been lagging behind mainly hampered by high access resistance and poor gate stack passivation [5–9]. In this work, we address these issues on a module level and demonstrate Ge enhancement mode nMOS FinFETs fabricated on 300mm Si wafers implementing optimized gate stack (D it 11 eV −1 ·cm −2 ), n+-doping (Nd > 1×10 20 cm −3 ) and metallization (ρ c = 1×10 −7 Ωcm 2 ) modules. L G ∼ 40 nm devices achieved I on = 50 µA/µm at I off = 100 nA/um, S ∼ 124 mV/dec, at V DD = 0.5V. The same gate stack and contacts were deployed on planar devices for reference. Both FinFET and planar devices in this work achieved the highest reported g m /S sat at 0.5 V to date for Ge nMOS enhancement mode transistors to the best of our knowledge at shortest gate lengths.