Modulations in electrical properties of sputter deposited vanadium oxide thin films: Implication for electronic device applications

Abstract

• Optimized growth of polycrystalline VO 2 films on SiO 2 /Si substrates by Sputtering. • Appreciable insulator to metal transition (IMT) observed down to 23 nm film thickness. • Film thickness induce systematic modulation in IMT order and IMT temperature. • Low resistivity (∼10 −2 Ω-cm) achieved for insulator state in 23 and 38 nm films. Engineering electronic properties of VO 2 across its insulator to metal transition enable to design wide range of electronic devices operating with low voltage such as memristor, field effect transistor, and in neuromorphic device as an active circuit element. We investigated the electrical and structural properties of sputter deposited VO 2 thin films grown on SiO 2 /Si substrates. In polycrystalline VO 2 films, we observed appreciable insulator to metal transition (IMT) down to film thickness of 23 nm. Further, thickness dependence study reveals a systematic variation in the IMT order between 30-3000, accompanied by modulation in transition temperature and hysteresis. The genesis of the modulations is attributed to morphological and structural growth dynamics. Significantly, we have attained low values for insulating states (∼10 −2 Ω-cm) in low dimensional thin films (23 and 38 nm), which are desirable for Joule heating driven IMT based VO 2 devices with low voltage switching, as well as for sensing applications.