HIGH PERFORMANCE STEP-EDGE SUPERCONDUCTING QUANTUM INTERFERENCE DEVICE ON SAPPHIRE SUBSTRATE AND METHOD OF MANUFACTURING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a high performance step-edge SQUID on a sapphire substrate, and a method of manufacturing the SQUID.;SOLUTION: A YBCO step-edge junction and SQUID on the sapphire substrate using CeO₂ as a buffer layer are manufactured. A steep step-edge is formed in the CeO₂ buffer layer by an Ar⁺ ion milling of the buffer layer over a shadow mask having an overhang end structure. An overhang end structure allows for an extended time of milling for forming a deep steep-edge within the buffer layer. A step angle is greater than 81° as measured by AFM. A high quality YMCO film is then epitaxially grown by pulse laser deposition. After patterning, the YBCO step-edge junction displays an RSJ-type I-V characteristic. The sapphire-based YBCO step-edge SQUID is installed onto a SQUID microscope system. The SQUID manufactured by a step-edge technique exhibits excellent magnetic field modulation, high imaging quality, and low noise.;COPYRIGHT: (C)2003,JPO