High-rate low-temperature dc pulsed magnetron sputtering of photocatalytic TiO2films: the effect of repetition frequency

Abstract

The article reports on low-temperature high-rate sputtering of hydrophilic transparent TiO 2 thin films using dc dual magnetron (DM) sputtering in Ar + O 2 mixture on unheated glass substrates. The DM was operated in a bipolar asymmetric mode and was equipped with Ti(99.5) targets of 50 mm in diameter. The substrate surface temperature T surf measured by a thermostrip was less than 180°C for all experiments. The effect of the repetition frequency f r was investigated in detail. It was found that the increase of f r from 100 to 350 kHz leads to (a) an improvement of the efficiency of the deposition process that results in a significant increase of the deposition rate a D of sputtered TiO 2 films and (b) a decrease of peak pulse voltage and sustaining of the magnetron discharge at higher target power densities. It was demonstrated that several hundreds nm thick hydrophilic TiO 2 films can be sputtered on unheated glass substrates at a D = 80 nm/min, T surf < 180°C when high value of f r = 350 kHz was used. Properties of a thin hydrophilic TiO 2 film deposited on a polycarbonate substrate are given.

Two-Functional Direct Current Sputtered Silver-Containing Titanium Dioxide Thin Films

“…The microhardness H , effective Young’s modulus E * and resistance to plastic deformation, which is proportional to the ratio H 3 / E *2 [26] were measured for ~950 nm thick Ti–Ag–O films as a function of partial pressure of oxygen (see Fig. 9).…”

Nanostructure of photocatalytic TiO2 films sputtered at temperatures below 200°C

“…The magnetrons were supplied by a pulsed Advanced Energy Pinnacle Plus + 5 kW power supply unit operating in asymmetric bipolar mode at the repetition frequency f r = 350 kHz with duty cycle t/T = 0.5 and the average pulse magnetron current I da kept at 3A and pulse power densities W da ranging from 60 to 70 W cm À2 according to deposition conditions used; W da was averaged over the whole target area. The high repetition frequency of pulses f r = 350 kHz ensured a strong improvement of (i) the efficiency of deposition process and (ii) the PCA of sputtered TiO 2 films [22]. Films were sputtered in the oxide mode on unheated glass (25 mm  25 mm  1 mm) substrates located at the substrate to target distance d s-t = 100 mm with the deposition rate a D % 10 nm/min.…”

“…Correlations between the deposition parameters and the structure of TiO 2 films sputtered at high repetition frequency f r = 350 kHz [22] are discussed in detail.…”

RF Magnetron Sputtering Deposition of TiO2 Thin Films in a Small Continuous Oxygen Flow Rate

“…To avoid using a high substrate temperature, high power impulse magnetron sputtering (HiPIMS) can also be used as an alternative [15,22]. The goal is to increase the energy of the incident ions, as rutile requires higher energy to crystalize than anatase [23][24][25]. This can be seen in the work of Nezar et al where, without any substrate bias, the deposited films consisted of anatase TiO 2 , and only after the application of a −75 V substrate bias could the peak for the rutile phase be noticed in XRD analysis [26].…”