Biaxially aligned TiN layers have been deposited by reactive unbalanced magnetron sputtering. In this work, a mechanism for the resulting microstructure and biaxial alignment of the deposited TiN layers will be discussed. According to the described model, the resulting biaxial alignment is caused by an overgrowth mechanism (zone T) due to an anisotropy in growth rate of the different oriented grains towards the incoming material flux. Hence, the in-plane alignment will mainly depend on two parameters: the mobility during the growth (zone T condition) and the spread on the incoming material flux. This spread on the incoming material flux has been calculated by an earlier published Monte Carlo simulation program of the transport of sputtered particles towards the substrate. The model for the mechanism of biaxial alignment is validated by comparing the experimental and theoretical influence of target-substrate distance and working pressure on the resulting in-plane alignment. (c) 2005 Elsevier B.V All rights reserved.