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Reactive magnetron sputtering of transparent conductive oxide thin films: Role of energetic particle (ion) bombardment

Published online by Cambridge University Press:  08 February 2012

Klaus Ellmer  and
Thomas Welzel
Klaus Ellmer*
Affiliation:
Helmholtz-Zentrum für Materialien und Energie GmbH, 14109 Berlin, Germany
Thomas Welzel
Affiliation:
Helmholtz-Zentrum für Materialien und Energie GmbH, 14109 Berlin, Germany
*
a)Address all correspondence to this author. e-mail: [email protected]
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Abstract

Transparent conductive oxides (TCOs) are degenerately doped compound semiconductors with wide band gaps (Eg > 3 eV), which are used as transparent electrodes in optoelectronic devices. Reports on the influence of negative ions on the electrical properties of TCO films are reviewed and compared with our results. It was reported that the radial resistivity distributions depend (i) on the excitation mode of the magnetron (direct current or radio frequency), (ii) on the erosion state of the sputtering target, and (iii) on the density of the ceramic targets. This can be explained by the fact that the negative ions in magnetron discharges (in our case O−) are generated at the target surface and accelerated toward the growing films. Their energy and their radial distribution depend on the discharge voltage and the shape of the emitting surface, i.e., of the erosion groove. Ways for reducing the effect of negative ion bombardment are discussed.

Keywords

Plasma depositionTransparent conductorElectrical properties
Type
Reviews
Information
Journal of Materials Research , Volume 27 , Issue 5: Focus Issue: Plasma and Ion-Beam Assisted Materials Processing , 14 March 2012 , pp. 765 - 779
Copyright
Copyright © Materials Research Society 2012

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References

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