TIME-OF-FLIGHT ANALYSIS OF THE PLUME DYNAMICS OF LASER-ABLATED 6H-SILICON CARBIDE

The mass and velocity distributions of neutral species, ejected from a laser-ablated 6H-SiC target, are measured by time-of-flight mass spec troscopy. The laser-generated Flume is shown to consist of atomic sili con and carbon and small neutral clusters. Measured values of the mean kinetic energies of neutral Si and SiC2 species are 1.1 and 1.5 eV, r espectively, when a 6H-SiC target is irradiated with 248 nm radiation at a power density of 1x10(8) W/cm(2). The kinetic energy distribution of Si+ ions is also measured for comparison with the neutral species, and shows a peak in the distribution at 38 eV. These data illustrate that an electronic, and not a thermal, mechanism for particle emission is active during the ablation of a 6H-SiC target. The relationship be tween the dynamics of the photoablation process and the properties of pulsed-laser-deposited films is also briefly discussed. (C) 1995 Ameri can Institute of Physics.