Ultraviolet annealing of thin films grown by pulsed laser deposition

In this paper, we report the results of ultraviolet UV.annealing of tantalum oxide and tantalum films deposited on Si 100.and quartz by pulsed laser deposition PLD.. The effects of annealing pressure and time on the structural and optical properties have been studied. Ellipsometry was used to determine the refractive index and thickness of the films, while Fourier transform infrared spectroscopy FTIR.and UV spectrophotometry were used to identify tantalum pentoxide Ta2O5.formation and determine the optical band gap and transmittance. The FTIR and UV spectra reveal a strong dependence of the film properties on the annealing parameters used with pressure being the most sensitive. Under optimum annealing conditions, the refractive index of the layers was found to be around 2.18 which is close to the value of the bulk Ta2O5 of 2.2, while an optical band gap of 4.2 eV and an optical transmittance in the visible region of the spectrum greater than 85% were obtained, which compare very favourably with films produced by other techniques. q2000 Published by Elsevier Science B.V. All rights reserved.