Indium-Gallium-Zinc-Oxide (IGZO) Nanowire Transistors

We report high-performance amorphous Indium-Gallium-Zinc-Oxide nanowire field-effect transistors (α-IGZO NW-FETs) featuring an ultrascaled nanowire width (W_NW) down to ~20 nm. The device with 100 nm channel length (L_CH) and ~25 nmW_NWachieves a decent subthreshold swing (SS) of 80 mV/dec as well as high peak extrinsic transconductance (G_m,ext) of612~μ S/μ mat a drain–source voltage (V_DS) = 2 V (456~μ S/μ matV_DS= 1 V). The good electrical properties are enabled by using an ultrascaled 5 nm high-kHfO2as the gate dielectric, a water-free ozone-based atomic layer deposition (ALD) process, and a novel digital etch (DE) technique developed for indium-gallium-zinc-oxide (IGZO) material. By using low-power BCl3-based plasma treatment and isopropyl alcohol (IPA) rinse in an alternating way, the DE process is able to realize a cycle-by-cycle etch with an etching rate of ~1.5 nm/cycle. The scaling effects on device performance have been analyzed as well. It shows that the downscaling ofW_NWimproves the SS notably without sacrificing ON-state performance, and the shrinking ofL_CHboosts theG_m,ext. The ultrascaledα-IGZO NW-FETs could play an important role in applications where high performance and high density are highly desired.