The current status of epitaxial technology towards high Tc electronics is summarized. Properties and processing maturity were compared for various oxide single crystals to give hints for the choice of substrate. Such problems in YBa2Cu3O7 (YBCO) film growth as precipitate formation and cracking were quantitatively investigated and shown to be solved by carefully preparing the substrate surface and by optimizing buffer layers and growth conditions. It is now possible to perform ideal layer-by-layer growth of various oxide films on atomically flat substrates by laser MBE to explore not only high Tc electronics but also a possible new field of oxide electronics.
