Metallic sputtering growth of crystalline titanium oxide films on unheated glass substrate using inductively coupled plasma assisted direct current magnetron sputtering

An inductively coupled plasma (ICP) assisted direct current (dc) magnetron sputtering system was used for depositing titanium oxide (TiOx) films on unheated glass substrates. The partial pressure of oxygen PO2 and the type of gas injection were varied to control the oxygen flux in the vicinity of the substrate. At radio frequency (rf) power to generate ICP Prf = 500 W, dc magnetron sputtering current Id = 0.8 A and total pressure PT = 0.5 Pa, a sudden decrease in the electron density Ne in the vicinity of the substrate occurs at PO2 ≈ 0.26 Pa, which corresponds to sputtering transition from metallic mode to oxide mode, and the deposition rate aD decreases significantly from ~ 10 nm/min to ~ 0.7 nm/min. When a gas mixture of oxygen and argon was lead into the chamber near the target, golden yellow TiO film with a well-crystallized structure was obtained under metallic mode of sputtering and transparent amorphous TiOx films were synthesized under oxide mode of sputtering. When oxygen was separately introduced to the vicinity of the substrate, various TiOx films with good crystallinity, including rutile and anatase, were obtained by varying PO2 under the metallic mode of sputtering. Transparent polycrystalline rutile and anatase films were grown on unheated glass substrate at aD ≈ 10 nm/min. Additionally we discussed about the low-temperature growth of crystalline TiOx films based on the results.