5:15 PM - 5:30 PM
[16p-411-6] High Signal-to-Noise Ratio pMUT Rangefinder Utilizing Epitaxial PMnN-PZT/Si Transducer
Keywords:Piezoelectric Micromachined Ultrasound Transducer (pMUT), Pb(Mn, Nb)O3-Pb(Zr, Ti)O3 (PMnN-PZT) epitaxial thin film, Rangefinder
Recently, ultrasonic rangefinder based on AlN Piezoelectric Micromachined Ultrasound Transducer (pMUT) has been developed for consumer electronics applications such as proximity sensing, gesture recognition etc.. However, there is much room for improvement of the device performance from the view of the performance of the piezoelectric material. Signal-to-noise ratio (SNR) determining the maximum measurement range and accuracy is proportional to e31,f2 or (e31,f2/ε)2 when mechanical or electronic noise is dominant, respectively, where e31,f and ε are the piezoelectric coefficient of the piezoelectric thin film and dielectric constant. Considering these noises exist in the system, both figures of merit (FOMs) i.e. e31,f2 and (e31,f2/ε)2 should be large to create a high performance rangefinder.
C-axis oriented Pb(Mn,Nb)O3-Pb(Zr,Ti)O3 (PMnN-PZT) epitaxial thin film on Si (e31,f: 14.5 C/m2, relative dielectric constant: 200~300) we have developed promises to improve the rangefinding performance because it exhibits much higher FOMs than not only AlN-based thin films but also typical PZT polycrystalline thin films. In this study, we prototyped pMUTs mounted with a PMnN-PZT epitaxial thin film, and evaluated its range finding performance. As a result, we successfully demonstrated this pMUT exhibited an excellent range finding performance. It can provide a 2.2 m working range at only 1 Vp-p drive voltage in case that 12 dB is set as the SNR threshold, which proves the potential maximum range-finding ability for reflection mode was >1 m. The optimization of the design of device and receiver circuit is expected to further improve the performance.
C-axis oriented Pb(Mn,Nb)O3-Pb(Zr,Ti)O3 (PMnN-PZT) epitaxial thin film on Si (e31,f: 14.5 C/m2, relative dielectric constant: 200~300) we have developed promises to improve the rangefinding performance because it exhibits much higher FOMs than not only AlN-based thin films but also typical PZT polycrystalline thin films. In this study, we prototyped pMUTs mounted with a PMnN-PZT epitaxial thin film, and evaluated its range finding performance. As a result, we successfully demonstrated this pMUT exhibited an excellent range finding performance. It can provide a 2.2 m working range at only 1 Vp-p drive voltage in case that 12 dB is set as the SNR threshold, which proves the potential maximum range-finding ability for reflection mode was >1 m. The optimization of the design of device and receiver circuit is expected to further improve the performance.