-Boron (B) doped Aluminium Nitride (AlN) thin film ((B, Al)N) was synthesized by DC-RF coupled co-sputtering and post processed for three different annealing temperatures. The structural properties was studied by X-ray spectra and observed the mixture of cubic BN and hexagonal AlN when annealed up to 300 °C. Increased crystallite size showed the influence of both B doping as well as annealing temperature on crystallite properties of (B, Al)N. Compressive and tensile stress was noticed with all samples and observed high value for cubic BN phase at 300 °C. Dislocation density and strain were also changed by the influence of B doping at high temperatures (> 200 °C). AFM images were showed the rough surface of B doped AlN thin film at 400 °C than other temperatures. The FESEM images revealed the particle agglomeration during B doping into AlN at high annealing temperatures. Elemental composition analysis by EDS spectra were also evidenced the change in surface structure as the effect of annealing.