Formation of silicon dioxide layers during UV annealing of tantalum pentoxide film

In this paper, the effects of ultraviolet (UV) annealing on films deposited by photo-induced chemical vapour deposition (photo-CVD) have been investig ated using ellipsometry and Fourier transform infrared spectroscopy (FTIR) measurements. It was found that SiO2 could be formed at UV annealing temper atures above 350 degreesC and its thickness (several nm) depends on anneali ng time, temperature and annealing gas such as N-2 and O-2 as well as the T a2O5 thickness. X-ray photoelectron spectroscopy (XPS) and HF etching confi rmed that the SiO2 formed on the surface of the Ta2O5 after the UV annealin g step. Results show that the active oxygen species play an important role in the improvement of layer properties during UV annealing. (C) 2000 Elsevi er Science B.V. All rights reserved.