Deposition of crack-free 30 µm AlN on IDT/ZnO/Si for wave guiding layer acoustic wave applications

Realization of packageless acoustic waveguiding sensors on basis of AlN/IDT/ZnO/Si structure was studied. The influence of ZnO and AlN deposition parameters and interdigital transducer structure on the performance of the device is discussed. The thick AlN layer, up to 30 μm, was deposited on IDT/ZnO/Si under optimized conditions for the growth of crack-free layers. Film texture and crystalline quality were examined by using X-ray diffraction methods. Surface morphology and interfaces between layers were investigated by transmission electron microscopy and atomic force microscopy. Acoustic performances of devices were characterized by a network analyzer.