Ultrasonic transducer is used for biological imaging. High frequency ultrasound has high spatial resolution. Higher frequency, however, induces lower deep resolution because of the large sound attenuation. The electromechanical coupling coefficient kt2 of generally used PVDF (Polyvinylidene Difluoride) is not enough for practical applications. We previously reported the transducer with ScAlN thick film on silica glass rod, operating at 44 MHz (kt2=11.9%) . Lead-free ScAlN with large piezoelectricity is suitable for medical applications. In this study, we report for the first time the fabrication of ScAlN free-standing plates with 0.105 mm and 0.117 mm thickness by using hot target sputtering growth.