Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

1 Publication
Epitaxial thin films of undoped ZnO grown by reactive pulsed magnetron sputtering
Vinnichenko, M.; Rogozin, A.; Shevchenko, N.; Kolitsch, A.; Moeller, W.;
The process of ZnO thin film growth by reactive pulsed magnetron sputtering is optimized to enable formation of epitaxial layers on Al2O3 (0001) substrates. The effects of the oxygen partial pressure, substrate temperature (Ts), base pressure, state of the target and substrate are investigated. X-ray diffraction (XRD) phi-scans suggest formation of the epitaxial ZnO layers with two types of domains in the case of chemically cleaned substrate (Ts=550°C, high oxygen, and base pressure of 5•10-7 mbar). One type of domains is 30° rotated relatively to the dominating orientation. Employing the target presputtering and additional substrate cleaning in oxygen plasma at the same other parameters, the formation of two-domain structure is suppressed and single-domain structure is obtained without additional buffer layers. The XRD rocking curve full width on half maximum is of 0.409°. According to spectroscopic ellipsometry analysis, the highly in-plane ordered ZnO films show no grading of optical constants and have significantly lower optical absorption. The Lorentz oscillator broadening obtained from the dielectric function is significantly smaller for the improved layer that also points to a higher ordering of the material. The oxygen plasma treatment of the sapphire substrate is shown to be crucial for preparation of epitaxial ZnO film with high in-plane alignment.
Keywords: ZnO thin film, in-plane ordering, reactive pulsed magnetron sputtering, optical properties
  • Poster
    E-MRS Spring Meeting, 29.05.-02.06.2006, Nice, France

Publ.-Id: 9136 - Permalink