We report the deposition of cobalt oxide thin films at 68 degrees C-138 degrees C using alternating injections of dicobalt hexacabonyl tert-butylacetylene (CCTBA) and ozone. The films consisted of Co3O4 and CoO, and no impurities were detected. The films were grown in atomic layer deposition mode at 68 degrees C with a growth rate of 0.083 nm/cycle, and the exposures of CCTBA and O-3/O-2 required for growth rate saturation were 2.5 x 10(6) and 5 x 10(8) L, respectively. Films deposited at low temperatures showed excellent step coverage. However, thermal decomposition of CCTBA followed by ozone oxidation was the dominant process at higher temperatures, especially during long precursor exposures. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.008202esl] All rights reserved.