Diagnostics of the ions produced by laser ablation of TiC and TiB2

The composition and the kinetics of the plume produced during the pulsed laser deposition of TiC and TiB2 coatings on metal substrates was studied under film growth conditions. Mass analysis of ions of the ejected material was performed by time of flight mass spectroscopy TOF-MS.and showed the presence of Tiq, Cqduring TiC ablation and Bq, Bq2 , Tiq during TiB2 ablation. The kinetic energies KE.of the ions depended on the laser fluence. At the ablation threshold laser fluence 0.5 Jrcm2. the KE of the species was less than 1 eV, while, at intermediate fluence regimes above 1 Jrcm2., a significant enhancement of the ablated ions KE ;200 eV.was observed. At higher fluence regimes above 3 Jrcm2., the velocity of the light-emitting particles produced by the excimer laser ablation was measured using a streak camera, between 1.5 and 6=106 cmrs and scaled linearly with laser fluence. These results were used in establishing relations between the nature of the plume produced by target ablation and structural properties of the deposited ceramic films. q1998 Elsevier Science B.V.