Germanium-Tin (GeSn) P-Channel Fin Field-Effect Transistor Fabricated on a Novel GeSn-on-Insulator Substrate

Germanium–tin (GeSn) p-channel fin field-effect transistor (p-FinFET) was realized on a novel GeSn-on-insulator (GeSnOI) substrate. The high-quality GeSnOI substrate was formed using direct wafer bonding technique and was layer-transferred from a 300-mm GeSn/Ge/Si donor wafer. Material quality was examined using atomic force microscopy, high-resolution transmission electron microscopy, Raman spectroscopy, and high-resolution X-ray diffraction. The fabricated GeSn p-FinFETs exhibit a small subthreshold swing (
${S}$
) of 79 mV/decade at
${V}_{\text {DS}}$
of −0.05 V (by a device with
${L}_{\text {CH}}$
of 200 nm and
${W}_{\text {Fin}}$
of 30 nm), good control of short channel effects, and high intrinsic transconductance (
${G}_{m,\text {int}} = 702\,\,\mu \text {S}/\mu \text{m}$
at
${V}_{\text {DS}}$
of −0.5 V for
${L}_{\text {CH}}$
of 80 nm). Low-temperature mobility analysis was performed on the GeSn p-FinFETs. High effective hole mobility (
$\mu _{\text {eff}}$
) (210 cm
²
/
$\text {V}\cdot \text {s}$
at 290 K and 398 cm
²
/
$\text {V}\cdot \text {s}$
at 5 K) is achieved. The GeSn p-FinFETs presented in this paper exhibit the highest
${G}_{m,\text {int}}/{S}_{\text {sat}}$
at
${V}_{\text {DS}}$
of −0.5 V for all the reported GeSn p-FETs to date.