A NEW METHOD FOR THE REDUCTION OF DROPLET DEPOSITION ONTO LASER-DEPOSITED THIN METAL-FILMS

Two important drawbacks of laser ablation etching and deposition, i.e. target roughening and droplet emission, were investigated for nanosecond pulsed excimer laser ablation of metals, metal alloys and silicon. In contrast to the behaviour of oxides, droplet emission of these materials decreases with increasing laser fluence. Prolonged ablation of smooth surfaces leads to increasing roughening of the target surfaces. At the same time, the number and average size of the emitted droplets increase. Both roughening and droplet emission are reduced considerably by varying the azimuthal angle of the laser beam while keeping the polar angle of incidence constant, As a consequence, the density of droplets condensed from the ablation plume on thin films is also greatly reduced.