Study of material emission in ArF and KrF excimer laser ablation of yttria stabilized zirconia single crystals

Yttria stabilized zirconia (YSZ) (100) single crystals have been irradiated with ArF (193 nm, tau = 23 ns) and KrF (248 = nm, tau = 34 ns) excimer lasers. Ablation rate and surface morphology of the target, deposition rate on a crystal quartz, and temporal evolution and emission analysis of the laser induced plumes have been studied under oxygen pressures in the 10(-5)-10(-1) mbar range. The influence of spot size (0.3-8 mm(2)) and laser fluence (0.2-12 J/cm(2)) have been analyzed. The ablation of YSZ initiates a typical laser plume which rapidly expands during the first microseconds and particulates emitted at low velocity after some hundreds of microseconds. Deposition rate does not depend on pressure from 10(-5) to around 10(-2) mbar, but strongly decreases at higher pressures as a consequence of a shock wave formation. Spectrographic analysis of plumes indicates that emission is mainly due to zirconium and yttrium, both in neutral and single ionized states. No molecular species have been identified. The ablated material per incident photon is the same for both wavelengths, and no important differences are found in the dynamics and composition of the laser plumes. (C) 1998 Elsevier Science S.A.