Type of presentation: Poster

MS-3-P-2956 Microstructural analysis of metal oxide coatings synthesised using novel energetic deposition methods

Murdoch B. J.¹, Mayes E. L.¹, Field M. R.², Partridge J. G.¹, McCulloch D. G.^1,2

¹School of Applied Sciences, RMIT University, GPO Box 2476, Melbourne, VIC 3000, Australia, ²RMIT Microscopy and Microanalysis Facility, RMIT University, GPO Box 2476, Melbourne, VIC 3000, Australia

matthew.field@rmit.edu.au

The possibilities for new metal oxide based materials is forever growing with the introduction of novel deposition methods which allow precise control of the deposition parameters and the ability to dope in order to tailor properties. The conditions used for the deposition of these coatings has an influence on the microstructure which in turn plays an important role in determining physical properties, such as the optical transmission and electrical conductivity. In addition, for many metal oxide materials the structure-property relationship is not well understood. In this work, filtered cathodic arc (FCVA), DC magnetron sputtering (DCMS) and high power impulse magnetron sputtering (HiPIMS) were utilised to reactively grow metal oxide coatings (HfO2 and ZnO) within an oxygen atmosphere.

FCVA deposition is a scalable energetic growth technique which allows for the synthesis of nanoscale coatings with tuneable properties. In this technique, a conductive target material (in this case, our metal) is ablated with a low voltage/high current electron flux. The metal ions are directed through a magnetic double bend towards the substrate through an oxygen environment. FCVA utilises a fully ionised plasma in which the energy of deposition can be controlled by applying an electrical bias to the substrate, heating or by modifying the processing pressure [1]. Thin film coatings grown using FCVA have been shown to have a low rms roughness and a high density [1], which is ideal for device applications. DCMS (low energy neutrals) and HiPIMS (high plasma density) were also selected to grow coatings. In conventional DCMS, inert gas ions (such as argon) are accelerated towards a negatively biased target material. When the target is sputtered, the target material is ejected and forms a thin film coating on the substrate placed nearby within the vacuum. HIPIMS is a technique based on magnetron sputtering, but unlike magnetron sputtering, HIPIMS, uses extremely high power density pulses, achieving a greater ionisation of the sputtered material during deposition [2,3].

The authors gratefully acknowledge the Australian research council (ARC) for funding. They would also like to thank the RMIT microscopy and microanalysis facility and the Australian Synchrotron for assistance with micro-characterisation.

Fig. 1: Cross sectional TEM bright field image of a Zn1-xMgxO film with compositional variations through the thickness.	Fig. 2: Cross sectional TEM dark field image of the same region from figure 1 highlighting cubic MgO (100) planes.
Fig. 3: EELS areal density line scan of the marked region in figure 1, taken from the Zn and Mg core loss edges.