Photo-Process of Tantalum Oxide Films and Their Characteristics

Abstract

TaOx film formation by a photo-CVD method using TaCl5 as a source material is examined. The deposition rate increases with increasing growth temperature and decreasing chamber pressure down to 1 Torr. The leakage current of the formed TaOx film decreases drastically with annealing in the presence of both UV-irradiation and an oxygen ambient after deposition (p-O2 annealing), when the underlying layer contains Si. The leakage current density is 10-8 A/cm2 at the 4 MV/cm electric field. The dielectric constant for MIS structure capacitors decreases with decreasing TaOx thickness, but does not decrease much with p-O2 annealing. In addition, the mechanisms of reduction of the leakage current with p-O2 annealing are discussed.