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 <; 2×10¹¹ eV^-1·cm^-2), n+-doping (Nd > 1×10²⁰ cm^-3) and metallization (ρ_c = 1×10^-7 Ωcm²) 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.