Effect of Kr/O2-Plasma Reactive Sputtering on Ferroelectric Nondoped HfO₂ Formation for MFSFET With Pt Gate Electrode

We have investigated the effects of the Kr/O
₂
-plasma reactive sputtering on the nondoped HfO
₂
thin-film formation for ferroelectric gate metal-ferroelectrics-Si field-effect transistor (MFSFET). The remnant polarization was increased while the coercive voltage (
${V}_{c}$
) was decreased for 5-nm-thick HfO
₂
formed by the Kr/O
₂
-plasma sputtering followed by the postmetallization annealing (PMA) utilizing the Pt gate electrode compared to the film formed by the Ar/O
₂
-plasma sputtering. The excellent fatigue properties until 10
¹⁰
cycles were realized under the ±4 V/
$5~\mu \text{s}$
input pulses. The memory window (MW) of 1.2 V was obtained under 2.5 V operation in the drain current (
${I}_{D}$
)–drain voltage (
${V}_{G}$
) characteristics for the fabricated MFSFET.