Formation of Single-crystal CoSi2 Buffer Layers on Si(100) Substrates by High Dose Co Ion Implantation for the Deposition of YBa2Cu3O7−x Thin Films

Abstract

High quality single-crystal CoSi2 layers have been successfully formed on Si(100) using low energy high dose Co ion implantation followed by subsequent annealing method as a buffer layer for the deposition of YBa2Cu3O7−x (YBCO) thin films. Rutherford backscattering spectrometry with channeling (RBS-C) measurements showed that CoSi2 layers after annealing at temperatures between 850 and 950 °C had a minimum yield Xmin of about 3%. X-ray diffraction (XRD) spectra revealed that CoSi2 layers had the same orientation as the Si(100) substrates. Phi scan XRD spectra proved that CoSi2 layers epitaxially grew in the cube-on-cube epitaxial growth mode with respect to the Si(100) substrates. YBCO films and CeO2/YSZ buffer layers were deposited on CoSi2/Si(100) substrates via laser ablation and electron beam evaporation, respectively. θ-2θ, ω, and φ scan XRD spectra illustrated that YBCO films and CeO2/YSZ buffer layers had the epitaxial structure both in a-b plane and along the c-axis. YBCO films grown on this multilayered structure demonstrated excellent superconducting properties with the zero resistance transition temperature Tc0 of 87–90 K. The transition width (ΔTc) was about 1 K. Orientation and epitaxial crystalline quality of YBCO films and CeO2/YSZ buffer layers were confirmed by XRD and RBS-C characterization. All films consisted of c-axis oriented grains. RBS-C spectra indicated a high degree of crystalline perfection with a channeling minimum yield for Ba as low as 8%, and interdiffusion between the YBCO film and buffer layers or between the YBCO film and the substrate was limited. This multilayer system shows the possibility for the application of YBa2Cu3O7−x thin films on technical Si substrates in the field of hybrid superconductor-semiconductor technology.