Study of off-stoichiometric aluminum nitride thin films: a simple method of fabricating distributed Bragg reflector for ultraviolet A by RF magnetron sputtering (Conference Presentation)

Aluminum nitride (AlN) thin films were studied to assess the dependence of their optical properties on their chemical and structural characteristics. The AlN thin films used for the study were deposited by RF magnetron sputtering with an aluminum nitride target reactively sputtered with a mixture of Ar and N2 gases.Resulting AlN thin films were further studied in the form of Distributed Bragg Reflector (DBR) that consists of stoichiometric AlN thin films (high-n layer) and an off-stoichiometric AlN thin films (low-n layer). The DBR was designed for the UV-A spectrum region exploiting negligible extinction coefficient of these AlN thin films, demonstrating the fabrication of DBR with a single sputtering target. By incrementally adding a high-n/low-n pair, the evolution of optical properties of the DBR was studied with respect to its structural transformation.