Direct thermal oxidation of CuO film from Cu2O as proved by x-ray diffractometry and Raman spectroscopy

Abstract

Copper film was deposited onto silicon (100) substrates in a two step process, firstly from copper to Cu₂O, then from Cu₂O to CuO. Preliminary x-ray diffractometry was done in the first step and only the typical silicon (100) peaks of the substrate and a single peak for monoclinic structure of Cu₂O were observed. No further peaks were obtained from latter XRD scans of the samples. This suggests a phase transformation of the Cu₂O to an amorphous CuO. Raman spectroscopy was done for further analysis. Two of the three phonon modes of CuO were observed from Raman spectroscopy of the final product. No Raman peaks for Cu₂O were obtained. These served to confirm that complete oxidation was achieved for the first and second steps. The absence of crystal peaks from the XRD of the final product and the broad CuO peak at 634.38 cm^-1 strongly suggest that sputter deposited copper metal was fully oxidized to an amorphous CuO film.