The growth of ultrathin films of copper on polycrystalline ZrO2

X-ray photoelectron spectroscopy (XPS/XAES) and work function measurements (WF) have been used to study the Cu/ZrO2 interface. Copper was deposited up to a thickness of 26 Angstrom at room temperature (RT) and up to 8 Angstro m at 673 K. At RT deposition it was found that, after the formation of just about 1 ML, copper starts to form three-dimensional clusters, exhibiting a Stranski-Krastanov growth process. At 673 R. 3D copper clusters begin to f orm from the very early stages of deposition. which reveals a stronger 3D c haracter. The XPS results did nor show any strong interaction between ZrO2 and Cu. Copper clusters exhibited core-level shifts due to both final and i nitial state effects. Work function measurements carried out during deposit ion at 673 R yielded additional information about the copper growth mode an d the copper-zirconia interaction, which is consistent with the XPS results . Furthermore, the work function of clean ZrO2 was measured as 3.1+/-0.1 eV from the width of the ultraviolet photoelectron spectrum (UPS). (C) 2000 E lsevier Science B.V. All rights reserved.