THE EFFECT OF IN-SITU LASER ANNEALING ON LASER-ABLATION DEPOSITED GARNET-FILMS

We have studied the influence of in situ laser annealing on the growth of garnet films by pulsed laser deposition. The KrF excimer laser tha t is used for ablation also provides in situ laser irradiation to the film with an energy density in the range 60-130 mJ/cm(2). Results show that laser annealing helps crystallize the mm and affects the film mi crostructure dramatically depending upon the annealing laser fluence. When using a substrate temperature of 570 degrees C, a laser irradiati on at a low fluence of 60 mJ/cm(2) induces crystallization and the fil m consists of densely packed grains. At 100 mJ/cm(2), the film is part ially melted resulting in a very smooth film surface and a decrease in crystallization. Ablation starts to occur at an energy density of 130 mJ/cm(2) for these garnet films. We also show that such laser anneali ng does not lead to a significant reduction in the required substrate temperature for crystallization even though the transient temperature rise can be high enough to melt the film.