Y₁Ba₂Cu₃O_7–x multilayer structures with a thick SiO₂ interlayer for multichip modules

Abstract

For high temperature superconducting multichip modules and other related electronic applications, it is necessary to be able to fabricate several Y1Ba2Cu3O7–x (YBCO) layers separated by thick low dielectric constant dielectric layers. In this work, we report the successful fabrication of YBCO/YSZ/SiO2 (1–2 μm)/YSZ/YBCO multilayer structures on single crystal yttria stabilized zirconia (YSZ) substrates. In contrast to previously reported work, the top YBCO layer did not show any cracking. This is due to a technique that allows for stress relief in the SiO2 layer before the second YBCO layer is deposited. The top YBCO layer in our multilayer structure had Tc = 87 K and Jc = 105 A/cm2 (at 77 K), whereas the bottom YBCO layer had Tc = 90 K and Jc = 1.2 × 106 A/cm2 (at 77 K). We also showed that the quality of the bottom YBCO layer was preserved during the fabrication of the multilayer due to the annealing process during which O2 diffused into the YBCO, replacing the O2 lost during the deposition of the top YBCO layer.