Influence of Substrate Bias Voltage on the Properties of Sputtered Aluminum-Scandium Thin Sheets

Julien Kovac, Heinz-Rolf Stock, Hans-Werner Zoch

Oberflaechentechnik, Stiftung Institut für Werkstofftechnik (IWT), Bremen, Germany..

DOI: 10.4236/jsemat.2012.22018                

Abstract

Thin sheets (20 μm - 30 μm) of an aluminum-scandium alloy were manufactured by magnetron sputtering with a homogeneous thickness distribution. The influence of bias voltage on the sheet properties was investigated. Steel sheets of 100 μm were employed as substrate and were coated in a dc magnetron sputtering unit fitted with a rectangular target of aluminum 2.0 w% scandium master alloy. After deposition, the substrates were dissolved in an oxidizing medium and thus freestanding aluminum-scandium thin films were obtained. The homogeneous thickness was achieved by a reciprocal movement of the substrate. The influence of a radio frequency bias voltage on the coating properties was investigated. The bias voltage resulted in an important coarsening of the columnar structure as well as an increase of the roughness and hardness. Additionally, a low bias voltage could intensively reduce the coating defect density without altering too much the sheet properties.

Keywords

Aluminum-Scandium Alloy; Magnetron Sputtering; Freestanding Thin Films; Bias Voltage

Conflicts of Interest

The authors declare no conflicts of interest.

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