Hot target magnetron sputtering process: Effect of infrared radiation on the deposition of titanium and titanium oxide thin films

Abstract

Titanium-based thin films are synthesized by the magnetron sputtering of a titanium target in pure argon or in a mixture of argon and oxygen (reactive regime) in three experimental configurations: a hot target configuration for which the target is thermally disconnected from the cooled magnetron body, a cold/conventional target configuration, and a cold target configuration with an additional infrared source introduced in the chamber to understand the role of the radiation on thin film properties. In hot configuration, the target temperature and its emissivity are measured and compared to a 0D steady state model taking into account the main different cooling mechanisms. IR radiations constitute the major part of the total energy deposited on the substrate during hot target magnetron sputtering, whereas an increase of target temperature allows a rise of sputtered Ti and Ti + species fluxes and slightly affect their kinetic energy. In reactive regime, the obtained films are constituted of polycrystalline anatase TiO2, and an increase of target/IR source temperature leads to an improvement of crystallinity. In pure argon, hot configuration seems to enhance its porosity, induces columns exhibiting sharp-features, slightly modifies its crystalline properties and helps to decrease internal compressive stress.

Au-Ag/TiO2 Thin Films Preparation by Laser Ablation and Sputtering Plasmas for Its Potential Use as Photoanodes in Electrochemical Advanced Oxidation Processes (EAOP)

“…TiO 2 thin films grown using different deposition techniques, including thermal evaporation, sputtering, sol-gel, electrodeposition, chemical evaporation, and pulsed laser deposition, have been successfully obtained [3,[15][16][17][18][19][20][21]. Laser ablation and magnetron sputtering techniques has been studied separately, as independent techniques to synthesize thin films of oxides [3,[22][23][24]. Their combination of producing thin films by sputtering and their modification, by adding other elements such as metals through laser ablation, allows taking advantage of the intrinsic characteristics and advantages of these techniques.…”

Sputtering onto liquids: a critical review

“…It can be speculated here that an increase in target temperature leads to an increase in sputtering yield (as reported in, e.g., [ 177 ]) which causes heating of the host liquid and subsequent formation of larger NPs in the limited volume of the solution. A heated target may also emit IR radiation [ 178 ], which subsequently also heats the liquid.…”

Target heating and plasma dynamics during hot magnetron sputtering of Nb

“…Meanwhile, the obtained error could be explained by: (a) formation of metal compounds, e.g. oxides, on the target surface during its heating in the air; (b) the emissivity determination at low target temperatures, which are close to the pyrometer detection threshold; (c) the temperature gradient across the target surface and depth during the emissivity determination because of low thermal conductivity of Nb; (d) variation of the emissivity along the target radius [3].…”

“…In order to improve the productivity, hot magnetron sputtering (HMS) has been envisaged, as it ensures a significant increase in the deposition rate. This approach implies to thermally insulate the sputter target from the water-cooled assembly, where permanent magnets are located, by inserting spacers with a low thermal conductivity [1][2][3]. In this scheme, the power applied to the source is not limited by the Curie point of the magnets used for the magnetron effect.…”

“…Nb has a relatively low thermal conductivity (54 W (m•K) −1 ) and a high melting point (2750 K at 1 atmosphere). All these features put Nb into a rather different category of materials, as compared to those used for the HMS systems so far (Ti [3,6,9,10], Cr [5,11], Cu [12], Ni [13], Si [14], Li [15]). Nevertheless, Nb-based coatings are attractive for research community due to their high corrosion resistance [16], good biocompatibility [17], and superconducting properties [18].…”