Surface and interface properties of superconducting YBa2Cu3O7-x thin films on GaAs using yttrium stablized ZrO2/Si3N4 as a buffer layer

High temperature superconducting YBa2Cu307 - x. (YBCO) thin films have been deposited onto IXI-V semiconductor GaAs substrates. The deposition temperature of the YBCO layer could be increased to as high as 650 °C without apparently degrading the GaAs substrate due to the use of Si3N4 as a subbottom buffer on the GaAs surface. The growth of highly c-axis oriented YBCO films on GaAs was enhanced by using yttrium stabilized Zr02 (YSZ) as a subtop buffer between YBCO and Si3N4. Surface and cross-sectional scanning electron microscopy revealed excellent surface and interface properties. The good interfaces were further confirmed using Auger electron spectroscopy depth profiling of the samples. The preservation of the GaAs surface due to the use of a dual buffer layer of YSZ/Si3N4 after YBCO deposition was demonstrated by photoreflectance measurement on the GaAs surface after removing YBCO, YSZ, and Si3N4 layers.