Inventors:
Thirumalai Venkatesan - Washington DC, US
Bin Ming - College Park MD, US
Ratnakar Vispute - Columbia MD, US
International Classification:
H01L021/44
H01L021/48
H01L021/50
H01L027/108
H01L029/76
H01L029/94
H01L031/119
H01L023/12
Abstract:
YBCO step-edge junctions and SQUID on sapphire substrates using CeOas a buffer layer are fabricated. A steep step-edge is formed in the CeObuffer layer by the Ar ion milling of the buffer layer over a shadow mask having an overhang end structure which allows for an extended time of milling for forming a deep steep step-edge within the buffer layer. The step angle is greater than 81 as measured by AFM. A high quality YBCO film is then epitaxially grown by pulse laser deposition. After patterning, the junctions display RSJ-type I-V characteristics. The sapphire based YBCO step-edge SQUIDs are installed onto a SQUID microscope system. SQUIDs fabricated by the step-edge technique exhibit excellent magnetic field modulation, high imaging qualities, and low noise.