LASER-ABLATION OF PB(TI0.48ZR0.52)O-3 TARGET - CHARACTERIZATION AND EVOLUTION OF CHARGED SPECIES

Time-of-flight mass spectrometry and covariance mapping technique were used to investigate the formation of charged species in the laser ablation of a Pb(Ti0.48Zr0.52)O3 target. Mass spectra were taken both in high vacuum and in an oxygen environment in order to clarify the effect of oxygen on the plume composition. The analysis of charged species in the plume has been carried out as a function of the distance between the target and spectrometer axis. The relative abundance of atomic, monoxide, and heavy ions has been measured and discussed. The velocities of atomic ions in the laser plume have been evaluated. Pb transport from target to substrate has been found to be mainly due to Pb-containing heavy species, whose abundance is greater in an oxygen environment with respect to a high vacuum condition. Ionic yield and covariance mapping analysis indicate that oxidation of ablated material starts at a distance very close to the plume range. The data show that, close to the deposition distance, a significant fraction of the plume is composed of heavy species containing Pb and oxides. These are appropriate precursors for the stoichiometric growth of ferroelectric films. The oxides are important carriers of oxygen atoms, and the Pb-containing heavy species preserve the metal stoichiometry with respect to Pb, which is the most volatile element in the composition. © 1995 American Institute of Physics.