Nd: YAG laser patterning of plasma-deposited high Tc superconducting thick films

Abstract

Advances in the development of high Tc superconducting thick film components and devices for microwave, millimeterwave, and submillimeterwave applications have led to the optimization of laser patterning techniques. Plasma-sprayed superconducting thick films of YBaCuO materials on polycrystalline alumina were laser etched using an Nd: YAG laser (λ = 1.06 μm) in the Q-switched mode. Spatial uniformity of the surface elemental distribution of Y, Ba, Cu, and Al was observed in the underlying laser-etched area. An etch rate of 7.5 μm/scan was calculated at an optimized laser fluencc of 1.8 × 104 J/cm2 for a translation rate of 2.54 cm/s, having patterning widths ranging from 5–15 μm with a heat-affected zone of 3 μm. An absorption length of 18.3 μm for the Nd: YAG laser was determined to be suitable for patterning thick films (20–80 μm) for device fabrication. The results are further compared to CO2 (λ = 10.6 μm) laser etching for patterning (250 μm) thick films.