Modulating the Residual Stress of Ion-Assisted TiO₂Films during Annealing with Film Thickness and Substrate Temperature

Abstract

Titanium dioxide (TiO2) films were prepared using ion-beam-assisted deposition on glass substrates with different film thicknesses and substrate temperatures. The effects of thermal annealing temperatures ranging from 100 to 300 °C on the residual stress of these films were investigated. The residual stress in the as-deposited films can be changed from compression to tension stress simply by increasing film thickness when the substrate temperatures are 150 °C. However, the residual stress in the as-deposited films can vary from tension to compression stress by increasing the substrate temperature when the film thickness was 600 nm. The residual stress, optical properties, and X-ray diffraction were investigated for TiO2 films during thermal annealing. The residual stress was gradient distribution in the film along the depth direction from the surface to the substrate. An annealing temperature of 200 °C is the key temperature when the TiO2 thin films will have the lowest residual stresses and highest refractive indices. However, the deposition only modulated the proper conditions of film thickness, substrate temperature, and annealing temperature to obtain the low residual stress and high refractive index for the TiO2 films.

Investigation of Optical and Electrochromic Properties of Tungsten Oxide Deposited with Horizontal DC and DC Pulse Magnetron Sputtering

“…The refractive index of WO 3 films reached 2.2 at the O 2 /Ar ratio over 0.6 for DC or DC pulse magnetron sputtering. 19,20) Furthermore, the refractive index increased with the increase of oxygen, and the DC pulse sputtering instability refractive indices were due to the influence of concentrated energy during the deposition process. 21) The DC pulse had enough concentrated energy to cause the extinction coefficients to be larger than that of the DC magnetron sputtering, as shown in Fig.…”