Thermal stability of heat‐reflective films consisting of oxide–Ag–oxide deposited by dc magnetron sputtering

Abstract

Transparent heat‐reflective films consisting of ITO–Ag–ITO or ZnO–Ag–ZnO were deposited onto soda‐lime glass by dc magnetron sputtering. In particular, the oxide layers were deposited from an electrically conductive oxide target. The transmittance in the visible range of the ITO–Ag–ITO film was more than 80% and the reflectance at 10 μm was nearly 95%. After the heat treatment at 650 °C, the transmittance of the films increased to nearly 85% and the reflectance at 10 μm was the same value of 95% as it was before the heat treatment. Moreover, the sheet resistance decreased to less than 4 Ω/cm2 by the heat treatment. Further, there were no visual changes or damage to the film up to 650 °C. The results showed that the ITO–Ag–ITO film was durable for the glass bending process. The ZnO–Ag–ZnO film also had high transmittance in the visible range and high reflectance in the infrared range, i.e., the transmittance in the visible range was more than 80% and the reflectance at 10 μm was 95%. However, these properties are much deteriorated by the heat treatment as compared with those of the ITO–Ag–ITO film.