Optical properties and thermal stability of alumina films grown by pulsed laser deposition

Thin films of aluminum oxide of thickness 293–433 nm were grown on fused silica substrates by pulsed laser deposition (PLD) of an alumina target with KrF excimer laser radiation. The effects of oxygen background pressure (0.5–50 Pa) and substrate temperature of room temperature to 800 °C were investigated on thickness, crystal-structure, optical properties and thermal stability of alumina films. It was found that PLD grows a weakly crystalline aluminum oxide film at in situ substrate temperature of 800 °C and oxygen background pressure of 5 Pa. Post-deposition annealing studies of amorphous alumina sample prepared at in situ temperature of 600 °C found that crystallization starts at 800 °C and forms δ alumina phase.