| The main goal of this research was to develop a process for fabricating a two-layer YBCO structure with a thick interlayer dielectric material. This structure could be used as the substrate of a superconducting multichip module (MCM). The research can be divided into four main parts: the construction of a deposition system, deposition of buffer layers, deposition of thick dielectrics, and rapid thermal annealing (RTA) experiments.;The sputter deposition system was built to enable a variety of YBCO, dielectric, and metal depositions to be performed while having complete control over deposition parameters. The system allows for a variety of geometries to be used in order to adapt to different deposition techniques.;An ion beam assisted deposition (IBAD) process utilizing sputtering was developed. Both CeO2 and YSZ were deposited onto silicon, Haynes alloy, and Pyrex substrates, representing crystalline, polycrystalline, and amorphous materials, respectively. Both materials exhibited biaxially texture on all three substrates. That is, they were aligned both in the c-axis direction normal to the substrate and in the a-b plane parallel to the substrate. The deposition of aligned buffer layers improved the critical temperature and current density Tc and Jc of the YBCO which was subsequently deposited.;A thick SiO2 deposition process was then developed. SiO 2 was reactively sputter deposited from a pure Si target. This allowed complete control over the oxygen stoichiometry of the film. SiO2 was selected as the dielectric because it is inexpensive and has a relatively low dielectric constant. Sputtered SiO2 films were found not to crack in the multilayer structure when deposited at temperatures of about 100°C.;After the individual processing steps were developed, several multilayer structures were built and characterized. These structures had the following film compositions: Pyrex/YSZ/YBCO/YSZ/SiO2/YSZ/YBCO. Each layer was characterized with atomic force microscopy, x-ray diffraction, and T c and Jc measurements.;Finally, RTA was investigated as a means of improving the Jc of YBCO films. The Jc improved dramatically, but the Tc generally decreased due to oxygen effusion from the films. |
