Effect of SiO2 buffer layer thickness on the properties of ITO/Cu/ITO multilayer films deposited on polyethylene terephthalate substrates

Transparent conductive ITO/Cu/ITO films were deposited on polyethylene terephthalate (PET) substrates with a SiO2 buffer layer by magnetron sputtering using three cathodes at room temperature. The effect of the SiO2 buffer layer thickness on the electrical and optical properties of ITO/Cu/ITO films was investigated. The ITO/Cu/ITO film deposited on the 40 nm thick SiO2 buffer layer exhibits a sheet resistance of 143Ω/sq and transmittance of 65% at 550 nm wavelength. Highly transparent ITO/Cu/ITO films with a transmittance of 80% and a sheet resistance of 98.7Ω/sq have been obtained by applying −60 V substrate bias.

► A SiO2 buffer layer is inserted between the ITO/Cu/ITO film and PET substrate.
► The effect of SiO2 layer thickness on properties of ITO/Cu/ITO films is studied.
► The proper SiO2 layer thickness lowers the sheet resistance of ITO/Cu/ITO films.
► A SiO2 buffer layer has little effect on optical transmittance of ITO/Cu/ITO films.
► The 40 nm SiO2 buffer layer reveals a better figure of merits of ITO/Cu/ITO films.