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
< 2×10
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.