Atomic-Level Analysis of Sub-5-nm-Thick Hf0.5Zr0.5O2 and Characterization of Nearly Hysteresis-Free Ferroelectric FinFET

We report ultra-thin 2-nm-, 3-nm-, and 5-nm -thick Hf
_0.5
Zr
_0.5
O
₂
(HZO) thin films using atomic-level characterization of ferroelectric fin field-effect-transistors (Fe-FinFET). First, the results of high-resolution grazing incidence X-ray diffraction (GI-XRD) using synchrotron radiation (1.5 GeV with a wavelength of 0.155 nm) revealed that the HZO thin films had a clear orthorhombic (
${o}$
) crystalline phase; even the 2-nm-thick HZO film had this type of phase. In addition, a nano beam diffraction (NBD) confirmed the
${o}$
phase in HZO. The proposed Fe-FinFETs exhibited sub-60-mV/decade subthreshold slopes (SS) and nearly hysteresis-free behaviors compared with baseline HfO
₂
FinFETs. The
${I}_{D}$
–
${V}_{G}$
transfer curves exhibited low
${I}_{\text {OFF}}$
and high
${I}_{\text {ON}}$
and were nearly free of drain-induced barrier-lowering (DIBL) in the statistical results. When
${L}_{{\text {G}}} > {W}_{{\text {Ch}}}$
(
${L}_{{\text {G}}}/{W}_{{\text {Ch}}} >{1}$
), most of the Fe-FinFETs exhibited SS < 60 mV/decade.