Laser crystallization studies of barium strontium titanate thin films

It is reported about laser crystallization investigations of the amorphous thin-film ceramic Ba0.7Sr0.3TiO3 (BST) with platinum electrodes on silicon substrates using ArF and KrF excimer lasers. The film thickness is an important parameter and was adjusted to minimize crack formation. For each film thickness the different laser parameters, such as pulse energy density, pulse number, and pulse length, were optimized. Thermal modeling was applied for the analysis of laser processing. During the preparation and crystallization process, the substrate temperature never exceeded 450 °C. For the first time, BST thin films have been crystallized by applying UV laser pulses for producing high k planar structures. The best electrical properties were obtained at a film thickness of 95 nm. The mechanisms resulting in the damaging of the thin films by short laser pulses were investigated systematically.