Photo-Process of Tantalum Oxide Films and Their Characteristics

Abstract

TaO x film formation by a photo-CVD method using TaCl 5 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 TaO x film decreases drastically with annealing in the presence of both UV-irradiation and an oxygen ambient after deposition (p-O 2 annealing), when the underlying layer contains Si. The leakage current density is 10 -8 A/cm 2 at the 4 MV/cm electric field. The dielectric constant for MIS structure capacitors decreases with decreasing TaO x thickness, but does not decrease much with p-O 2 annealing. In addition, the mechanisms of reduction of the leakage current with p-O 2 annealing are discussed.