Growth of thin films of Co3O4 by atomic layer deposition

Thin films of cobalt oxide were made by atomic layer deposition (ALD), using Co(thd)(2) (Hthd = 2,2,6,6-tetramethylheptan-3,5-dione) and ozone as precursors. Films were deposited on soda-lime glass and single crystals of Si(100). Pulse and purge parameters for ALD-type growth were established and such growth was found to occur for depositions within the temperature range of 114-307 degrees C. A preferred (100)-orientation was observed at the low end of the temperature range for films deposited on soda-lime glass and Si(100). At the high end of the temperature range, films deposited on Si(100) showed (111)-oriented growth, while films deposited on soda-lime glass substrates were unoriented. The electrical resistivity of as-deposited films on soda-lime glass were in the range of 0.13-4.48 ohm cm and showed a non-monotonic dependence on film thickness, with a minimum for films with a large proportion of grain boundaries. (C) 2007 Elsevier B.V. All rights reserved.