**Abstract**

Aluminum nitride (AlN) thin films have aroused the interest of researchers due to their unique physicochemical properties. However, further studies on these semiconductor materials are still necessary to establish the manufacturing of highperformance devices for applications in various areas, such as telecommunications, microelectronics, and biomedicine. This chapter introduces AlN thin film technology that has made a wide range of applications possible. First, the main physicochemical properties of AlN, its wurtzite crystalline structure, and the incorporation of oxygen during the thin film deposition process are presented. Furthermore, the growth of AlN films by different techniques and their applications as a buffer layer and sensing layer are summarized. Special attention was given to the sputtering deposition process and the use of sputtered AlN films in SAW sensors.

**Keywords:** aluminum nitride, wurtzite crystalline structure, sputtering, thin film, buffer layer, sensing layer, SAW sensors
