Ge p-MOSFETs With Scaled ALD $\hbox{La}_{2} \hbox{O}_{3}/\hbox{ZrO}_{2}$ Gate Dielectrics

Dielectric thin films of La
₂
O
₃
/ZrO
₂
deposited by atomic layer deposition (ALD) are investigated to be employed in Ge Schottky barrier p-MOSFETs. La
₂
O
₃
is used as a thin passivation layer and is capped by atomic-layer-deposited ZrO
₂
as a gate dielectric. As the gate contact TiN capped by W is applied, midgap-level trap densities of ~ 3-4 × 10
¹²
eV
^-1
cm
^-2
and subtreshold slopes down to 115-120 mV/dec are achieved. The devices show negative threshold voltages of -0.5 to -0.6 V, as well as peak hole mobility values of ~ 50-75 cm
²
/V · s. Equivalent oxide thickness (EOT) is reduced to 0.96 nm upon postmetallization annealing without degrading the interface properties. The results show the scaling potential of the ALD La
₂
O
₃
interlayer capped with ZrO
₂
gate dielectrics for the integration into sub-1-nm EOT Ge p-MOSFET devices.