Studies on interface of Cu/Al and Al/SiO2/Si

We prepared Cu/Al and Al/SiO2/Si samples by sputtering Cu on Al metals and Al on SiO2/Si, respectively. We investigated the interfaces between Cu film and Al metal, or between Al film and SiO2/Si by XPS (X-ray photoelectron spectroscopy). From the results, we found that Cu metals were oxidized in the Cu/Al samples and changed to Cu+ and Cu2+. In addition, the thickness of Cu metal in Cu/Al and Al metal in Al/SiO2/Si are thought to be less than 100 Å. At the same time, the Cu film deposited by a sputtering method may be oxidized more than the Al metal, which is prepared by the method of cold rolling. The XPS results of Al/SiO2/Si samples indicate that there may be oxygen-reduced Al2O3-x layer on the interface between Al and SiO2, and that there are inhomogeneous SiO2-x in the Ar+ etched surface of the Al/SiO2/Si sample.