Влияние напряжения смещения подложки в процессе реактивного магнетронного распыления на супергидрофильные свойства плёнок TiO2
Authors: Шашин Д.Е. , Сушенцов Н.И. , Будкина И.М. 
Published: February 2025

Данная статья посвящена изучению влияния напряжения смещения подложки в процессе реактивного магнетронного распыления на супергидрофильные свойства плёнок TiO2. Описано технологическое оборудование для формирования супергидрофильных плёнок TiO2, а также сформирована серия плёнок при различных значениях напряжения на подложке. Приведены результаты исследования супергидрофильных свойств полученных плёнок. Разработаны технологические рекомендации по оптимальной величине напряжения смещения при формировании супергидрофильных плёнок TiO2методом реактивного магнетронного распыления.

Introduction. In modern instrumentation, vacuum technologies for sputtering weakly absorbing thin films of metal oxides are successfully applied to change the optical properties of lenses, mirrors and glasses of information and measuring devices. Such films improve optical and other characteristics, protect lenses from turbidity in an atmosphere with high humidity and increase the hydrophilicity of the surface. These properties can be obtained by producing thin films of titanium oxide (TiO2), which acquire superhydrophilic properties when exposed to ultraviolet radiation. The main method for producing TiO2 thin films is reactive magnetron sputtering of a titanium target in a plasma of oxygen and argon. The interest in magnetron technology for producing thin films on optical surfaces is due to the high growth rate of the film, the high purity of the resulting films, a wide range of variation in technological parameters, and low growth temperatures. It is known that the optical parameters of TiO2 thin films are determined by their crystal structure. The use of the nanoscale TiO2thin films expands the range of their use in various fields of instrumentation. The most effective way to control the size of crystallites during the production of films is to feed a bias voltage to the substrate. When a negative bias potential is fed to the substrate holder during the formation of the coating, positively charged ions of the working gas and the sputtered target move to the substrate. The number of adsorbed atoms on the surface of the film grows. This leads to over-sputtering of the growing coating, mixing of the atoms of the substrate material and the formed material, contributing to an increase in the transition layer between the film and the substrate. The use of the negative bias voltage allows to control the process of coating growth during sputtering. The aim of the research is to study the effect of the substrate bias voltage on the superhydrophilic properties of TiO2 films. To achieve this goal, the following tasks were tackled: synthesis of a series of TiO2 films with the use of reactive magnetron sputtering technology at different values of the substrate bias voltage, study into the superhydrophilic properties of the produced films under the exposure to UV radiation, development of recommendations for the optimal value of the bias voltage during the production of superhydrophilic TiO2 films by reactive magnetron sputtering. Conclusions: 6 samples of TiO2thin films on quartz glass substrates were synthesized with the use of the technology of reactive magnetron sputtering at different values of the substrate bias voltage during growth, the produced films exhibited transmission in the visible region (390-790 nm) and low in the ultraviolet (190-390 nm), which indicates a high degree of absorption of ultraviolet radiation by the produced TiO2films, the TiO2 films produced by the technology of reactive magnetron sputtering under UV radiation showed a contact angle of 58-62° before UV radiation exposure, it has been experimentally found that the superhydrophilic properties of TiO2 films improves with an increase in the substrate bias voltage. The figures of the contact angle of a water drop on a substrate coated with a TiO2 film decreased by 48-56 degrees after exposure to UV radiation for 120 minutes and reached a value of 2° for a film produced at 90 V of the bias voltage, however, a further increase in the bias voltage is not reasonable, since with an increase in the bias voltage above 90 V, it was not possible to produce a solid homogeneous film, due to the peeling of the coating due to a large number of crystalline defects and overvoltage in the film structure.