Photo-MOCVD of Cu thin films using Cu(hfa)(MHY) as precursor

Pure Cu thin films were deposited in the temperature range 120-220°C by Photo-MOCVD on different substrates using Cu(I) hexafluoroacetylacetonate 2-methyl-1-hexene-3-yne, Cu(hfa)(MHY), as molecular precursor. Without UV activation, a selective growth of Cu was observed on both Si and Ag surfaces detrimental to SiO2 surface but this selectivity has a tendency to be lost under photon irradiation. The growth rate is thermally activated and, for instance, values as high as 700 nm/min were obtained on (100)Si at 220°C. Surprisingly, the growth rate is significantly reduced under UV irradiation indicating that likely the photons favor the desorption of reactive species from the growing surface and have a low efficiency on the decomposition and, subsequently, the nucleation and growth. No impurity was detected by XPS analysis and the films exhibit resistivity very close to that of pure bulk copper