Diagnostics of the ions produced by laser ablation of TiC and TIB2

Abstract

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 Ti+, C+ during TiC ablation and B+, B-2(+), Ti+ during TiB2 ablation. The kinetic energies (KE) of the ions depended on the laser fluence. At the ablution threshold laser fluence (0.5 J/cm(2)) the KE of the species was less than 1 eV, while, at intermediate fluence regimes (above 1 J/cm(2)), a significant enhancement of the ablated ions KE (similar to 200 eV) was observed. At higher fluence regimes (above 3 J/cm(2)), the velocity of the light-emitting particles produced by the excimer laser ablation was measured using a streak camera, between 1.5 and 6 X 10(6) cm/s 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. (C) 1998 Elsevier Science B.V.