Cubic local order around Al and intermixing in short-period AlN/TiN multilayers studied by AlK-edge extended x-ray absorption fine structure spectroscopy and x-ray diffraction

Al K-edge extended x-ray absorption fine structure (EXAFS) experiments are performed on short-period TiN (50 nm)/AlN (Lambda = 1, 2, 3, 5, and 15 nm) multilayers prepared by dc magnetron sputtering on MgO(100). It is shown that the local order around Al is hexagonal down to Lambda = 3 nm and becomes clearly cubic B1 rocksalt-type below this thickness. This phase transition is correlated with x-ray diffraction results, which reveal increased compressive stresses in TiN layers for Lambda = 3 nm. In addition, EXAFS provides direct evidence of substitution of Ti for Al within AlN layers, as well as an estimation of Ti content as a function of layer thickness. (C) 2003 American Institute of Physics.