Effects of sputtering gas on the microstructure of Ir thin films deposited by HiPIMS and pulsed DC sputtering

• Published in: Surface & coatings technology 2021-04, Vol.412, p.127038, Article 127038
• Main Authors: Zenkin, S., Gaydaychuk, A., Linnik, S.
• Format: Article
• Language: English
• Subjects: Diamonds; Epitaxial growth; Helium; HiPIMS; Industrial applications; Ir thin films; Iridium; Magnetron sputtering; Melting points; Microstructure; Sputtering; Substrates; Texture control; Thermal stability; Thin films
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2021.127038

Due to its chemical inertness, hardness and thermal stability Ir finds a lot of industrial applications. One of the most important field is it use as a substrate material for the monocrystalline diamond heteroepitaxy. However, due to the extreme iridium price, as well as its high melting point, production of bulk iridium substrates is economically unfavorable. In this article we are focused on the Ir thin films production by pulsed DC and HiPIMS sputtering and study the effect of Ar and He working gases on the structure of the growing films. We have found that a sputtering rate reduction given by using of HiPIMS discharge in He is a one of the key factors of the intensified influence of the seed substrate and a growth of thermodynamically unfavorable iridium orientation. This combination can be used as a possible low-energy ion-assisted method for epitaxial growth of materials. •HiPIMS Ir film growth rate reduces from ≈1.6 nm/s (in Ar) to ≈0.1 nm/s (in He) at the same average power.•HiPIMS in He can significantly improve a growth thermodynamically unfavorable film orientations.•Crystallites (d