High-Temperature Superconductor Step-Edge Fabrication for the Implementation of RSFQ Circuits

[摘要] High-temperature superconductive (HTS) logic has become a large research field worldwide. TheHTS advantages compared to the low-temperature circuits are the reduced cooling requirements,increased or comparable operation speeds and the ease of manufacturing.The potential of HTS logic circuits is vast and surpassed by very few other technologies. However,before these circuits can reach the market, suitable simulation packages and fabrication processeshave to be designed.The simulation of HTS Rapid Single Flux Quantum (RSFQ) circuits are performed at temperaturesbetween 30 and 77 Kelvin. The noise sources in Josephson junctions (JJ's) are investigated andincorporated into these simulations. The results show that it is possible to operate these circuitsin this temperature range.An objective of this thesis is the fabrication of HTS step-edge JJ's. A process to fabricate thesejunctions was investigated and improved. This includes the etching of substrate steps with theuse of the argon ion mill, deposition of the YBCO thin films with the Pulsed Laser Deposition(PLD) system and the etching of the final circuit by the use of dry or wet etching.

[发布机构] Stellenbosch University