Beware of poor-quality MgO substrates: A study of MgO substrate quality and its effect on thin film quality

Autor: Jens Birch, Arni Sigurdur Ingason, Jeremy L. Schroeder, Johanna Rosen
Rok vydání: 2015
Předmět:
Zdroj: Journal of Crystal Growth. 420:22-31
ISSN: 0022-0248
DOI: 10.1016/j.jcrysgro.2015.03.010
Popis: Magnesium oxide (MgO) substrates are widely used for fundamental research of a large variety of materials. Our motivation is to make the research community aware of poor-quality MgO substrates. We acquired thirty MgO substrates from six different vendors and demonstrate that ‘single-crystal’ MgO substrates are not always single crystal, but can consist of multiple domains. These multiple-domain MgO substrates can have a significant impact on research results as demonstrated by a one-to-one correlation between the domain structure of MgO substrates and titanium nitride (TiN) thin films (i.e. poor-quality MgO substrates result in poor-quality TiN films). Poor-quality MgO substrates are shown to be a widespread problem with over 70% of the evaluated substrates exhibiting multiple domains, essentially disqualifying them as substrates for epitaxy. MgO substrate vendors and researchers are encouraged to work together to resolve the problem of inconsistent MgO substrate quality and the research community is encouraged to perform quality control of MgO substrates prior to thin film deposition. Quality control by vendors and/or researchers can be achieved by acquiring X-ray diffraction omega–phi maps in batch processes, as detailed in this paper. We also propose a simple quality grading system to differentiate MgO substrates of varying quality.
Databáze: OpenAIRE
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