Formation and Thermochromism of V O 2 Films Deposited by RF Magnetron Sputtering at Low Substrate Temperature

Abstract

Thermochromic VO2 films were deposited on substrates of silicon and Pyrex glass by reactive rf magnetron sputtering and characterized by thin-film X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS), atomic force microscopy (AFM) and spectrophotometry. Films with a VO2 single phase were formed above a fairly low temperature of 300° C by controlling precisely the oxygen flow ratio. The use of a nucleated substrate improved the crystallinity of the VO2 films deposited at low temperature. A negative substrate bias appeared to have an effect of favoring the formation of a VO2 single phase at a substrate temperature as low as 250° C.