Preparation And Properties Of Vanadium Oxide Thin Films By Magnetron Sputtering

Vanadium dioxide?VO₂?is a metal oxide which has thermal phase transition properties.With theincreasing temperature at approximately 68?,VO₂ film undergoes the semiconductor phase to high temperature metallic phase of reversible changes,and the associated great changes in optical and electric properties.The unique characteristics of VO₂ make it possible to make use of this film in photoelectric switch,smart window,infrared detector and other fields.So VO₂ films have a high potential value and broad application prospects.In this paper,VO₂ thin films were prepared by RF reactive magnetron sputtering.In the experiments,X-ray diffraction?XRD?,scanning electron microscope?SEM?and atomic force microscope?AFM?were employed to analyze the microstructures and surface topography of the VO₂films.The electrical properties and the application of VO₂ thin films in micro bolometer were studied.This paper mainly includes the following aspects:1.VO₂ thin films were prepared by Direct Current?DC?and Radio Frequency?RF?reactive magnetron sputtering respectively.The effects of different sputtering methods on the microstructure and surface morphology of the films were investigated.DC sputtering is prone to target poisoning,we cannot get the films we need.The surface of the films prepared by RF sputtering is uniform and dense,and is distributed in a tetragonal shape.2.VO₂ thin films with different properties were prepared on silicon substrates by controlling the oxygen flow rate.The structure and electrical properties of the films were characterized and analyzed.With the increase of the oxygen flow rate,the thin films grow along the?011?crystalline orientation and the grain size increases,the phase transition temperature of the films reduces from 341 K to 320 K,the width of the thermal hysteresis loop decreases from 32 K to 9 K.3.The effects of different sputtering power on the surface morphology and photoelectric properties of VO₂ thin films were investigated.The prepared films had a lower phase transition temperature at about47?.The increase of sputtering power leads to the increase of the grain size and thickness of the film,and then the hysteresis loop width of the film,and the transmittance of the films in the visible and infrared decreases gradually,and finally reaches zero.4.We found a more intuitive method for calculating the temperature coefficient of resistance ?TCR?,which is not necessary to use the activation energy of the material.We calculated the TCR of the films prepared at T=300 K,at the oxygen flow rate of 5sccm,the film TCR was-3.455%/k;The TCR of VO₂ thin films prepared by different sputtering power were-6.490%/k,-3.565%/k,-2.362%/k,which can meet the application conditions of micro bolometer.