공진주파수 스펙트럼법을 이용한 압전박막의 특성 평가

초록

We studied the characteristics of impedance and electromechanical coupling coefficient in ZnO and AlN thin films by using resonance frequency spectrum method. The response peak of impedance decreased with the decrease of thickness of piezoelectrics, the number of mode of response peak increased with the increase of substrate thickness. An error of kt2 estimated from input kt2 increased as the thickness of piezoelectrics decreased and the thickness of substrate increased. Also, the error was increased in case of a large acoustic impedance of substrate. It was found that the composite resonator operating in optimized condition could be designed through the resonance frequency spectrum analysis of composited resonator consisted of piezoelectric thin film and substrate.