Volume 82, Number 3, May 2008
Article Number 36002
Number of page(s) 5
Section Condensed Matter: Structural, Mechanical and Thermal Properties
Published online 23 April 2008
EPL, 82 (2008) 36002
DOI: 10.1209/0295-5075/82/36002

Synthesis of $\alpha$-Al2O3 thin films using reactive high-power impulse magnetron sputtering

E. Wallin1, T. I. Selinder2, M. Elfwing2 and U. Helmersson1

1  Plasma Coatings Physics Division, IFM Material Physics, Linköping University - SE-581 83 Linköping, Sweden, EU
2  Sandvik Tooling AB - SE-126 80 Stockholm, Sweden, EU

received 18 February 2008; accepted in final form 12 March 2008; published May 2008
published online 23 April 2008

$\alpha$-alumina coatings have been deposited directly onto cemented-carbide and Mo substrates at a temperature as low as 650 $^{\circ}$C using reactive high-power impulse magnetron sputtering (HiPIMS) of Al in an ArO2 gas mixture. The coatings consisted of plate-like crystallites, as revealed by scanning electron microscopy. $\alpha$ phase growth was retained over the studied range of substrate bias voltages (from floating potential up to -100V), with films exhibiting a slightly denser microstructure at higher bias voltages. X-ray diffraction indicated that the $\alpha$-alumina grains had a preferred orientation of (0001)-planes perpendicular to the substrate surface. X-ray analysis of films deposited at 575 $^{\circ}$C indicated the presence of $\gamma$-alumina, whereas films grown at 500 $^{\circ}$C or lower were X-ray amorphous.

68.55.-a - Thin film structure and morphology.
81.15.Cd - Deposition by sputtering.
81.05.Je - Ceramics and refractories (including borides, carbides, hydrides, nitrides, oxides, and silicides).

© EPLA 2008