ANALYSIS OF CHARGED FRAGMENTS EMITTED DURING EXCIMER LASER ABLATION OF YNI2B2C BOROCARBIDE TARGETS BY TIME-OF-FLIGHT MASS SPECTROMETRY

Excimer laser ablation of superconductive borocarbide material (YNi2B2C) in typical condition for the deposition of superconductive thin film has been studied by using time-of-flight mass spectrometry. The mass spectra show the presence of diatomic ions together with single ions of all the elemental species. While the yield of the single elemental metallic ions increases with the laser fluence, the non-metallic ions yield decreases. Such decrease is well correlated with the observation of light diatomics (B-2(+), C-2(+), or BC+) produced by aggregation processes in the plume, Moreover, the presence of aggregation/fragmentation processes in the plume has been also evidenced by using the covariance mapping technique. (C) 2002 Elsevier Science B.V. All rights reserved.