HiPIMS and Bipolar HiPIMS Techniques for Tunable Phase Formation of Yttrium Oxide Thin Films at Low-Temperature

This study investigates the deposition process and characterization of yttrium oxide thin films using high-power impulse magnetron sputtering (HiPIMS) and bipolar HiPIMS, which are advanced deposition technologies that can effectively use high energy for controlling energy flux to produce thin films. These two techniques require no heat for the control of phase formation of yttrium oxide thin films. The properties of the films were analyzed using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, ultraviolet–visible spectrometry, and water contact angle analyses. The results indicated that the energy of sputtered species can be effectively tuned by adjusting the process parameters, and it can then be used to achieve phase control of yttrium oxide thin films. The monoclinic phase is associated with a high number of oxygen vacancies in the films. The cubic phase with low oxygen vacancies produces more compact thin films with wide bandgaps. Therefore, the relationship between the process parameters and the resultant structural, morphological, and optical properties as well as the wettability of the deposited films is confirmed. This allows the film properties to be tuned to each application, enabling their use in various fields.