Atomic layer deposition of stoichiometric Co3O4 films using bis(1,4-di-iso-propyl-1,4-diazabutadiene) cobalt

• Cobalt oxide films were grown by ALD using a novel cobalt precursor and O3.
• The ALD temperature window was 120–250 °C with a growth per cycle of 0.12 nm/cycle.
• Cobalt oxide thin films showed excellent step coverage.
• Cobalt oxide films deposited at 250 °C were stoichiometric and crystalline Co3O4.

We report the deposition of cobalt oxide films at 120–300 °C using alternating injections of a novel liquid cobalt precursor, bis(1,4-di-iso-propyl-1,4-diazabutadiene)cobalt [C16H32N4Co, Co(dpdab)2], and ozone. The saturation doses of Co(dpdab)2 and O3/O2 were 4 × 106 and 1 × 108 L, respectively. The atomic layer deposition (ALD) temperature window was between 120 °C and 250 °C with a maximum growth per cycle of 0.12 nm/cycle. The deposited films showed excellent step coverage. Cobalt oxide films deposited at 250 °C consisted of stoichiometric and crystalline Co3O4.