Optimization of the experimental conditions for the preparation of a thin strontium titanate film by hydrothermal process

Abstract

A Taguchi orthogonal array design was implemented to optimize the experimental conditions for the preparation of a thin strontium titanate film on a Ti substrate using a hydrothermal process. The effects of such preparatory conditions as the strontium-concentration, pH-value, reaction temperature, reaction time and the substrate surface treatment were systematically studied. Results indicate that the effects of the reaction temperature and reaction time are the key variables influencing the relative crystal intensity (intensity of (110) SrTiO₃ peaks in XRD spectrum/intensity of (101) Ti peak in XRD spectrum) of the films obtained. By combining the optimal settings of the two most influential process variables, a polycrystalline, SrTiO₃-films was obtained, with improved crystallinity and a grain size of 0.2–0.4 μm and a dielectric constant of 360 at I MHz.

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