Influence of atomic layer deposition parameters on the phase content of Ta2O5 films

Ta2O5 films were grown in atomic layer deposition (ALD) process on barium b orosilicate glass substrates in the temperature range of 300-400 degrees C from TaCl5 and H2O. The film crystallinity was modified by precursor dosing and substrate temperature. The films deposited at temperatures somewhat ab ove 300 degrees C were partly crystallized, showing XRD reflections of hexa gonal delta-Ta-2 O-5 phase. The reflection intensities and film haziness de monstrated maxima at certain values of the TaCl5 pulse length. The film gro wth rate initially decreased with the increase in the pulse length. After e xceeding the TaCl5 pulse length value corresponding to the maximum in the c rystallinity, the Ta-2 O-5 growth rate was stabilized. The intermediate del ta-Ta-2 O-5 was transformed into the conventional low-temperature orthorhom bic beta-Ta-2 O-5 upon raising the growth temperature above 325 degrees C a nd increasing the TaCl5 doses. (C) 2000 Elsevier Science B.V. All rights re served.