AlN films were grown on silicon by DC reactive magnetron sputtering and Al/AlN/Si structures were fabricated to study the influence of post metalization annealing (PMA) and UV light. Thereafter, the samples were annealed at 350 oC for 30 minutes in presence of argon gas. Reduction of hysteresis as well as interface state density was observed as a result of PMA. On the other hand, a ledge appeared in C-V curves, which became prominent with light intensity. The leakage current increased significantly as a result of photo generated charge carriers.