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 °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 Ω cm and showed a non-monotonic dependence on film thickness, with a minimum for films with a large proportion of grain boundaries.