Impact of deposition temperature on structural and electrical properties of sputtered AlN/ Si (111) for CMOS compatible MEMS

Aluminium nitride (AlN) thin films are grown by reactive sputtering on Silicon (Si) with (111) orientation at low temperature (≤ 450 °C) for piezoelectric-based micro-electromechanical systems (MEMS). The grown AlN thin films were polycrystalline wurtzite hexagonal structure with a high texture coefficient for the (002) plane of orientation. The leakage current density by the current-voltage ( I-V) measurement was found to be as low as 1.6 ×10 −6 A cm −2 in the grown films. The trapped charges are crucial in controlling these electrical characteristics, and low interface trap density (6.72 ×10 10 cm −2 eV) was observed for the sputtered AlN grown at a substrate temperature of 300 °C. This study on the structural and electrical properties of AlN/Si (111) at low substrate temperature is compatible with the complementary metal oxide semiconductor (CMOS) process for constructing piezoelectric-based MEMS devices for various applications. • Polycrystalline AlN films are sputter deposited at temperatures below 400 °C. • 300 °C was sufficient for obtaining the high texture coefficient along (002). • The texture development and topography with temperature are explained. • A low leakage current of 1.6 ×10 −6 A/cm 2 is obtained. • A low interface trap density of 6.72 ×10 10 cm − 2 eV − 1 has been demonstrated.