Growth of tantalum pentoxide film by pulsed laser deposition

Thin films of Ta(2)O(5) have been deposited on quartz and silicon substrates by 532-nm (Nd:YAG) pulsed laser deposition (PLD) in various O(2) as environments. The influence of the deposition parameters, such as oxygen pressure, substrate temperature and annealing under UV irradiation using a 172-nm excimer lamp, on the properties of the grown films, has been studied. The refractive index of the films increases with increasing pressure of O(2). X-ray diffraction measurements show that the as-deposited films are amorphous at temperatures below 500 degrees C and possess orthorhombic (beta-Ta(2)O(5)) crystal structure at temperatures above 600 degrees C. The optical properties determined by UV spectrophotometry also strongly depend on the deposition parameters. At O(2) pressures above 0.15 mbar, the refractive index of the films was about 2.12 which is close to the bulk Ta(2)O(5) value of 2.2. Optical transmittance around 85% in the visible region of the spectrum was obtained at an oxygen pressure of 0.2 mbar, (C) 1999 Elsevier Science B.V. All rights reserved.