Laser patterning of Y-Ba-Cu-O thin-film devices and circuits

We report our studies on electrical properties of Y-Ba-Cu-O test devices and circuits fabricated using a laser-writing patterning technique. The patterning procedure is noninvasive, does not require a patterning mask, and does not contaminate nor damage the surface of patterned films. Our laser-written, oxygen-rich lines (typically 4–100 μm wide) possess excellent superconducting properties with zero resistivity at 89.5 K and critical current densities of above 2 MA/cm2 at 77 K. On the other hand, oxygen-poor regions are semiconducting and exhibit thermally activated transport, well described by a three-dimensional, variable-length hopping process. Their resistance below 100 K is above 10 MΩ/square. A number of test structures patterned by laser writing, such as a microbridge, coplanar transmission line, open-ended microwave resonator, photoconductive switch, and Y-Ba-Cu-O field-effect transistor, have been presented.