We have studied films of YBa2Cu3O7-δ (YBCO) grown on SrTiO3 substrates, which were implanted with high doses of Co (1 X 1016-5 X 1017 ions/cm2 at 100 keV). The indirect modification of YBCO by local ion implantation of Co into the substrate is investigated to evaluate the feasibility of a new planar technology for the fabrication of Josephson junctions. The modified YBCO might become a barrier region of a Josephson junction. We found a strong diffusion of the implanted Co ions out of the substrates into the YBCO films during the deposition process, forming YBa2Cu3-xCoxO7-δ. Our EDX and SNMS analyses show that the Co concentration x is homogeneous across the films. YBa2Cu3-xCoxO7-δ is well known to be an excellent barrier material for SNS-type Josephson junctions. Using a 1.4 μm thick photoresist mask, we have locally implanted Co into the substrates to study the lateral diffusion of Co into the YBCO film above the non-implanted region. We performed EDX analysis on cross-sectional TEM samples and found strong lateral diffusion of Co from the implanted substrate within the YBCO film located above the non-implanted region.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering