Structural Switch of AlN Sputtered Thin Films From (101) to (002) Orientation, Driven by the Growth Kinetics

Due to its wide bandgap, high thermal conductivity, high electrical resistivity, temperature independent piezoelectric coefficient, aluminum nitride (AlN) represents a material of great technological interest, for applications in RF MEMS devices, high power electronics, energy harvesting and optoelectronics [1]. In the specific case of piezoelectric applications, the performances of the device strongly depend on the AlN microstructural properties, because AlN thin films grown along c-axis orientation exhibit intense piezoelectric response, the (001) orientation having the highest piezoelectric constants [2].