Metal-oxide-semiconductor devices with UHV-Ga2O3(Gd2O3) on Ge(100)

Ultra-high vacuum (UHV)-deposited high Ga
₂
O
₃
(Gd
₂
O
₃
) was proved to passivate Ge effectively, as evidenced by comprehensive investigations including structural, chemical, and electrical analyses. The Ga
₂
O
₃
(Gd
₂
O
₃
)/Ge interface is revealed to be abrupt even being subjected to a 500degC anneal, a high kappa value of 14.5, a low leakage current density of ~10
^-9
A/cm
²
with a Fowler-Nordheim tunneling behavior, and well-behaved C-V characteristics are achieved. Furthermore, Ge self-aligned pMOSFETs with Al
₂
O
₃
/ Ga
₂
O
₃
(Gd
₂
O
₃
) as the gate dielectrics have demonstrated a high drain current and a peak transconductance up to 252 mA/mm and 143 mS/mm, respectively, of 1 mum-gate length.