AlN thin films have a wide range of applications in electronic devices. AlN thin films are used as a protective coating of thermo printing devices and also as a material of cold cathodes. Moreover, these thin films are the most promising piezoelectric materials for surface acoustic wave (SAW) applications. In this work, thin films of AlN were grown on glass and MS substrates by reactive DC magnetron sputtering. The crystallographic and micro-structural properties of sputtered AlN films were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. The films were found to be having hexagonal crystalline AlN structure in all cases irrespective of deposition parameters. However, Al peaks were also observed showing simultaneous metallic layer deposition. Grain growth was observed with increase in film thickness. Biasing resulted in better adhesion of the nitride film with the substrate. Hardness measurements were also made for different deposition parameters, but less significant changes were observed.