Measurement of the thermal conductivity of TiO2 thin films by using the thermo-reflectance method

The through-plane thermal conductivity of TiO2 thin films, with the thicknesses of 150 and 300 nm, deposited on silicon wafers and heat treated at several different temperatures was measured using the thermo-reflectance method which utilizes the reflectance variation of the films surface produced by the periodic temperature variation. The results showed that the thermal conductivities were 0.7–1.7 W m−1 K−1 and increase as the heat treatment temperature increases. They are explained by the grain size and the density of the heat treated films. Also the thermal conductivity of 300 nm thick film is larger than that of 150 nm thick film by 30%. The reason for that was assumed to be the thermal resistance between the thin film, metal film and the substrate.