High Temperature Superconducting Josephson Junctions on Silicon Substrates for RFCommunications

摘要

We have successfully fabricated and tested two types of high temperaturesuperconducting Josephson junctions on silicon. An assessment of the properties of these junctions shows that they are attractive candidates for rf applications. Step-edge SNS junctions fabricated with gold barriers exhibited the ac Josephson effect to over 100 GHz, with the power and frequency dependence of the current voltage characteristics in good quantitative agreement with the resistively shunted junction model. The resistances of these junctions were of order 1 ohm, and critical currents over 0.1 mA were obtained. Critical currents were observed to 76 K. Electron-beam modified Josephson weak links were also demonstrated on silicon. These devices exhibited microwave induced steps in the current voltage characteristics, magnetic interference patterns with strong central maxima, and sinusoidal magnetic interference patterns when imbedded in dc SQUIDs. We have also identified an approach to relieve thermal expansion stress in HTS films on silicon that would allow the fabrication of filters and other passive components with greatly improved performance at significantly lower cost than current techniques. jg p.1.