The preparation and characterization of AlPO 4 thin films via laser ablation of AlPO 4-H 4

Abstract

An excimer laser (KrF, 248 nm) was used to deposit well-dispersed thin films of aluminum phosphate onto a titanium nitride substrate from an AlPO 4-H 4 target. It was found that laser ablation of AlPO 4-H 4 results in AlPO 4 cristobalite or aluminum orthophosphate as well as AlPO 4 tridymite and amorphous materials depending upon the conditions. The effects of laser power, substrate distance, atmosphere, and temperature on thin-film formation were studied. Low substrate temperatures and pulse energies between 50 mJ and 100 mJ resulted in growth of AlPO 4 cristobalite or aluminum orthophosphate. Low laser-power density and high substrate temperatures produced AlPO 4 tridymite on the substrate TiN surface. These first examples of laser-ablated AlPO 4 films were characterized by X-ray diffraction, X-ray fluorescence, infrared spectroscopy (FTIR) and scanning electron microscopy.