The extraordinary role of the AlN interlayer in growth of AlN sputtered on Ti electrodes

Abstract

The structure of AlN layers grown on Ti with and without an AlN interlayer between the Si substrate and the Ti layer is investigated. The AlN grains take over the orientation of the Ti columnar grains in both cases. Surprisingly, the Ti grains do not take over completely the orientations of the AlN grains of the interlayer, and show the same columnar grain structure as the sample without interlayer. Hence, the structure of the AlN top layer is independent of the presence of an AlN interlayer below the Ti layer and is mainly determined by the Ti layer microstructure.