Comparison of co films deposited by remote plasma atomic layer deposition method with cyclopentadienylcobalt dicarbonyl [CpCo(CO)(2)] and dicobalt octacarbonyl [Co-2(CO)(8)]

Abstract

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 degrees C) and higher growth rate (similar to-1.2 angstrom/cycle) than the Co films deposited with CpCo(CO)(2) which had a process window of 125-175 degrees C and a growth rate of similar to 1.1 angstrom/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 similar to 15 and similar to 2% with the H-2 plasma, and similar to 8 and similar to 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 degrees C for the Co films deposited with Co-2(CO)(8) can be explained by high carbon content including Co-C bonds.