【International Papers】Reactive Sputter Deposition of Ga₂O₃ Thin Films Using Liquid Ga Target

      Researchers from the Institute for Technical Physics and Materials Science, Centre for Energy Research, Budapest, Hungary have published a dissertation titled " Reactive Sputter Deposition of Ga₂O₃ Thin Films Using Liquid Ga Target " in MDPI.

Abstract

      Ga₂O₃ is a promising material in the optoelectronics and semiconductor industry. In this work, gallium oxide thin films were deposited via radio frequency (RF) sputtering, using a liquid Ga target. The reactive sputtering was carried out using different oxygen flow rates and DC target potentials induced via the RF power. The thickness of the samples varied between 160 nm and 460 nm, depending on the preparation conditions. The composition and the refractive index of the layers were investigated via energy-dispersive spectroscopy, X-ray photoelectron spectroscopy, and spectroscopic ellipsometry, respectively. It was found that, through the use of a lower DC target potential, a better film quality and higher oxygen content can be achieved. The reactive sputtering was modeled based on the Berg model, with the aim of determining the sputtering yields and the sticking coefficient. It was shown that an increase in DC target potential leads to the preferential sputtering of gallium.

Figure 1. Photographs of the liquid Ga target in a Ni container inside the sputtering chamber, after sputtering at an oxygen flow rate of 12 sccm (a), and 32 sccm (b), and a schematic representation of the experimental setup (c).

Figure 2. A typical XRD pattern of the RF sputtered films; only the crystalline peaks of the substrate can be identified.

Figure 3. The oxygen atomic ratio of the sputtered gallium oxide films, determined via EDS, as a function of the oxygen partial pressure.

Paper Link：https://doi.org/10.3390/coatings13091550