Microstructure of films on buffered Si for microelectronic applications

(YBCO) films formed on Si with -stabilized and buffer layers which can be used for Josephson junctions are investigated by electron microscopy. The YBCO films on a buffer are single crystalline in contrast to the films on a buffer which tend to be polycrystalline. Different types of high-angle and low-angle grain boundaries which may have an impact on the appearance of weak links are analysed in detail. High-resolution electron microscopy combined with image simulation strongly suggests an oxygen depletion and an excess of copper at the boundaries.