Comparison of Co Films Deposited by Remote Plasma Atomic Layer Deposition Method with Cyclopentadienylcobalt Dicarbonyl [CpCo(CO)2] and Dicobalt Octacarbonyl [Co2(CO)8]

Co films were deposited by a remote plasma atomic layer deposition (ALD) method using either cyclopentadienylcobalt dicarbonyl [CpCo(CO) 2 ] or dicobalt octacarbonyl [Co 2 (CO) 8 ] as the Co precursor. The Co films deposited with the Co 2 (CO) 8 precursor showed a lower ALD process window (75–110 °C) and higher growth rate (∼1.2 Å/cycle) than the Co films deposited with CpCo(CO) 2 which had a process window of 125–175 °C and a growth rate of ∼1.1 Å/cycle. The Co films deposited using CpCo(CO) 2 showed an oxygen content of less than 1% with both the H 2 and N 2 plasma and about 13% carbon with the N 2 plasma and about 7–8% carbon with the H 2 plasma. In the case of Co 2 (CO) 8 , the carbon and oxygen contents were ∼15 and ∼2% with the H 2 plasma, and ∼8 and ∼21% with the N 2 plasma, respectively. The carbon impurities in the Co films deposited with CpCo(CO) 2 had a significant number of C–H bonds while Co–C bonds were dominant in the Co films deposited with Co 2 (CO) 8 . The retardation of silicide formation temperature up to 100 °C for the Co films deposited with Co 2 (CO) 8 can be explained by high carbon content including Co–C bonds.