J. Phys. IV France 09 (1999) Pr8-349-Pr8-355
Microstructure and deposition characteristics of κ-Al2O3S. Ruppi1 and A. Larsson2
1 Seco Tools AB, 73782 Fagersta, Sweden
2 Chalmers University of Technology and Göteborg University, 41296 Göteborg, Sweden
The aim of this work is to elucidate the influence of pressure in combination with different degrees of catalysis on the growth and microstructure of chemically vapour deposited (CVD) κ-Al2O3. The coatings were deposited at 1000 °C in a vertical hot-wall reactor. Hydrogen sulphide (H2S) was used as a doping agent. The experimental κ-Al2O3 coatings were deposited as multilayers and up to 8 layers of κ-Al2O3 were obtained with different process parameters in the same run. Thin TiN interlayers were deposited to separate the κ-Al2O3 layers. Growth rates of κ-Al2O3 as a function of pressure and dopant concentration were measured using scanning electron microscopy (SEM). The changes in the microstructure of the κ-Al2O3 layers were investigated using transmission electron microscopy (TEM). The growth rate of κ-Al2O3 could be strongly enhanced by applying H2S doping or by increasing the deposition pressure. κ-Al2O3 coatings which were deposited at differing process conditions did not exhibit any pronounced microstructural or morphological variations.
© EDP Sciences 1999