Transmission electron microscopy was used to study the interfacial reactions and crystallographic structure in high‐temperature sputtered Al alloy/TiN system. An intermediate layer and semispherical precipitates were observed as the reaction products during high‐temperature sputtering at 500 °C. Electron diffraction analysis indicated that the intermediate layer consisted of hexagonal AlN and cubic TiN. Semispherical precipitates were also found to consist of tetragonal Al3Ti. Additional energy dispersive x‐ray spectrometer analysis suggested that the intermediate layer was formed by the diffusion of Al atoms into the TiN film. ©1995 American Institute of Physics.