Improving on the yield and performance of high Tc rf SQUIDs

Optimization and passivation of HTS step-edge Josephson junction rf SQUIDs

“…The optimum ratio is lower than most reported values in the range of 0.5-1.0 [1]- [3], [5], [7], [8]. It is also significantly different from our rf SQUIDs of the same structure but fabricated using sputtered films for which is often 0.7.…”

“…However, if employing conventional photolithographic process, it is very difficult to pattern the junction to width less than 1 m with precision. Reducing the film thickness and consequently the ratio of the film thickness to step height has been found to reduce the value effectively [7]. However, there is a lower limit on the film thickness before film discontinuity occurs over the step.…”

“…However, there is a lower limit on the film thickness before film discontinuity occurs over the step. The most commonly Manuscript [3], [5], [7], [8]. The low value of 0.5 was used by Ma et al [7] to optimize their rf SQUIDs.…”

“…The most commonly Manuscript [3], [5], [7], [8]. The low value of 0.5 was used by Ma et al [7] to optimize their rf SQUIDs. The suitable ratio, however, depends on the microstructure of the step and the characteristics of the YBCO film which varies for different step angles and film growth techniques.…”