Atomic layer deposition and chemical vapor deposition of tantalum oxide by successive and simultaneous pulsing of tantalum ethoxide and tantalum chloride

Amorphous Ta2O5 films were grown by atomic layer deposition (ALD) or pulsed chemical vapor deposition (CVD) processes as a result of reactions between Ta(OC2H5)(5) and TaCl5. Pulses of evaporized Ta precursors were led into the reactor successively or simultaneously. H2O could be applied as a supplementary oxygen source, but the films could be grown also in a water-free process. Films were grown in the temperature range of 275-450 degrees C. The growth rate of the films obtained by CVD using simultaneous pulsing of precursors exceeded 2.5 times that of the films obtained in the ALD process, where only one metal precursor was applied at a time. The refractive index and permittivity of the films increased with the growth temperature and frequency of Ta precursor pulses, approaching the values characteristic of the films obtained in the conventional ALD or CVD processes.