Excimer laser patterning of epitaxial YSZ films grown on silicon

Epitaxial yttria-stabilised zirconia (YSZ) films grown on Si(100) were irradiated by KrF excimer laser (248 nm wavelength, 34ns pulse length). 50mum wide squares were patterned by imaging a mask under mild irradiation conditions and applying a varying number of laser pulses. The resulting morphology and chemical composition were studied. By increasing the number of pulses, the morphology of the irradiated area evolved from a cracked film surface to a final structure with exposed silicon over most of the surface, but also with YSZ globules that could not be removed by additional pulses. Of particular interest when using laser patterning with a high lateral resolution is the possibilty of the exclusively localisation of the damage within the irradiated area. The damaged lateral zone beyond the spot border was less than 1 mum after irradiation with thousands of laser pulses, and only around a few tenths of after a few pulses. We also prepared arrays of tracks (20 mum wide, 5 mum separation) by moving and irradiating the sample in a step-and-repeat process. The separation between tracks is not altered and suitable for selective epitaxial growth of other films. (C) 2002 Elsevier Science Ltd. All rights reserved.