Impact of deposition parameters on the characterizations of highly orientated aluminum nitride for film bulk acoustic wave resonator device

AIN thin films were grown on Si(100) and Al/Si(100) substrates by pulsed do sputtering system using 99.999% purity aluminum as target, and Ar+N-2 gas mixture as precursor. The impact of deposition parameters, including do power, deposition pressure and substrate temperature, on material properties has been investigated. A good correlation between film crystallinity and do power, as well as gas pressure; was addressed by x-ray diffraction, and verified by scanning electron microscope (SEM) and ellipsometry. It is found that highly c-axis oriented h-AIN can be obtained at low gas pressure and low deposition rate. For AIN on Al/Si(100) substrate, micro-crack was observed. which was assigned to the large thermal stress between AIN film and Al layer. Crack-free surface has been achieved by reducing the deposition temperature. The deposition mechanism of AIN deposition is discussed. This work provides a material foundation for filth bull; wave resonator (FBAR) devices fabrication.