Ž . Applied Surface Science 138–139 1999 587–592 Vacuum ultraviolet annealing of thin films grown by pulsed laser deposition Valentin Craciun a, ) , Doina Craciun a , Pascal Andreazza b , Jacques Perriere c , Ian W. Boyd d a Laser Department, National Institute for Laser, Plasma and Radiation Physics, Bucharest, PO Box MG-36, RO-76 900, Romania b Centre de Recherches sur la Matiere DiÕisee, UniÕersite d’Orleans, BP 6759, 45067 Orleans Cedex 2, France c Groupe de Physique des Solides, UniÕersites Paris VII et VI 2, place Jussieu, 75251 Paris Cedex 05, France d Electronic and Electrical Engineering, UniÕersity College London, Torrington Place, London WC1E 7JE, UK Abstract Ž . The effect of a post-deposition annealing treatment in 1 bar of oxygen at moderate temperatures -4508C under Ž . Ž . illumination by vacuum ultraviolet VUV radiation emitted by an excimer lamp upon thin ZrO and hydroxyapatite HAp 2 Ž . films grown by the pulsed laser deposition PLD technique was investigated. The optical and structural properties of the films were improved by this treatment, the lower the deposition temperature and, accordingly, the poorer the initial characteristics, the more significant the improvements. The combination of these two techniques allowed us to obtain at Ž . 2 temperatures below 3508C highly textured 020 ZrO films, exhibiting optical absorption coefficients lower than 5 =10 2 cm y1 and high refractive index values of around 2.25 in the visible region of the spectrum. The VUV treatment was also beneficial for the partially crystalline HAp layers containing tetracalcium phosphate and calcium oxide phases grown by the PLD technique under a low pressure oxidising atmosphere of only 10 y5 torr without any water vapours. After the VUV-assisted anneal, the crystalline structure and the stoichiometry greatly improved while the percentage of the other crystalline phases initially present was many times reduced. q 1999 Elsevier Science B.V. All rights reserved. PACS: 42.62.Cf; 78.20.Ci; 81.05.Je; 81.65.Mq Keywords: Vacuum ultraviolet lamps; Laser ablation; Thin films; Zirconium dioxide; Hydroxyapatite 1. Introduction Ž . The pulsed laser deposition PLD technique is well known for the quality of the layers grown at relatively lower substrate temperatures than other ) Corresponding author. E-mail: craciv@roifa.ifa.ro wx thin film deposition methods 1 . However, there are still many applications where a further reduction of the processing temperature is highly desirable. Previ- ous studies have indicated that the properties of the PLD grown layers degraded if the substrate tempera- ture employed was reduced below the optimal value, situated somewhere within the 5008 –8008C range, depending on the characteristics of the deposited material. In order to improve the properties of the 0169-4332r99r$ - see front matter q 1999 Elsevier Science B.V. All rights reserved. Ž . PII: S0169-4332 98 00457-7