Temperature and Electric Field Induced Metal-Insulator Transition in Atomic Layer Deposited Vanadium Dioxide Thin Films

摘要

Amorphous vanadium dioxide (VO$_{2}$) films deposited by atomic layerdeposition (ALD) were crystallized with an ex situ anneal at 660-670 ${\deg}$Cfor 1-2 hours under a low oxygen pressure (10$^{-4}$ to 10$^{-5}$ Torr). Underthese conditions the crystalline VO$_{2}$ phase was maintained, while formationof the V$_{2}$O$_{5}$ phase was suppressed. Electrical transition from theinsulator to the metallic phase was observed in the 37-60 ${\deg}$C range, witha R$_{ON}$/R$_{OFF}$ ratio of up to about 750 and critical transitiontemperature of 7-10 ${\deg}$C. Electric field applied across two-terminaldevice structures induced a reversible phase change, with a room temperaturetransition field of about 25 kV/cm in the VO$_{2}$ sample processed with the 2hr long anneal. Both the width and slope of the field induced MIT hysteresiswere dependent upon the VO$_{2}$ crystalline quality.