Top-seeded solution growth of SrTiO3 single crystals virtually free of mosaicity

Abstract

Strontium titanate (SrTiO3), a well-established traditional perovskite substrate as well as a promising substrate crystal for the epitaxy of new advanced perovskite-type thin films, suffers from the unavailability in adequate quality for the latter. To improve the situation attempts have been made to grow SrTiO3 at moderate temperatures (<1535°C) well below the melting temperature and under low temperature gradients by the top-seeded solution growth method. Based on very special modifications of the growth conditions, virtually mosaicity-free SrTiO3 single crystals in the 1–2cm range were obtained. High crystalline quality was verified by defect selective etching, rocking curve measurements, energy dispersive Laue mappings and by synchrotron X-Ray diffraction topography. The production of virtually subgrain- and dislocation free substrate crystals is essential to considerably improve characteristics of SrTiO3 based SQUIDs, transistors or memory devices and to allow an in-depth analysis of intrinsic and extrinsic factors influencing the properties of epitaxially grown oxide heterostructures.