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 devic es and circuits fabricated using a laser-writing patterning technique. The patterning procedure is noninvasive, does not require a patternin g mask, and does not contaminate nor damage the surface of patterned f ilms. Our laser-written, oxygen-rich lines (typically 4-100 mu m wide) possess excellent superconducting properties with zero resistivity at 89.5 K and critical current densities of above 2 MA/cm(2) at 77 K. On the other hand, oxygen-poor regions are semiconducting and exhibit th ermally activated transport, well described by a three-dimensional, va riable-length hopping process. Their resistance below 100 K is above 1 0 M Omega/square. A number of test structures patterned by laser writi ng, such as a microbridge, coplanar transmission line, open-ended micr owave resonator, photoconductive switch, and Y-Ba-Cu-O field;effect tr ansistor, have been presented.