Novel liquid cobalt precursor for metal atomic layer deposition

A novel liquid cobalt (Co) precursor, bis (diisopropylbutanamidinate)cobalt (DIPRoBA-Co), is proposed as the liquid Co precursor for metal atomic layer deposition (ALD). This precursor was synthesized and the Co ALD process using the obtained precursor was examined. This precursor is liquid and successfully achieves Co ALD with a liquid precursor instead of a solid one. Transmission electron microscopy observation shows that 5–6 nm thick Co metal film grows on a plasma silicon dioxide substrate step structure by this ALD using an ammonia, hydrogen and DIPRoBA-Co gas system with 80 cycles at 220 °C substrate temperature.