Investigation of the adhesion mechanism of NiCr layers on Al2O3 and AlN substrates

Mechanical pull tests supply information about whether a sufficient adhesive strength of a layer on a carrier is present for use, not, however, about the underlying adhesion mechanism. Sputterd NiCr layers on Al sub 2 O sub 3 and AlN substrates show a very high adhesive strength in pull tests. Therefore, the endeavor was made to investigate, with analytical procedures, the ashesion mechanism which is responsible for this. For the characterization of the surfaces and layers, element analyses were carried out with XPS and AES, and cross-sections were looked through the metallized substrates with HRTEM. The results allow the conclusion that with both ceramics, the good adhesion is due to the chemical bonding between Cr, Al and O.