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This paper presents a 1.2-mm diameter high fill-factor array of 1261 piezoelectric micromachined ultrasonic transducers (PMUTs) operating at 18.6 MHz in fluid for intravascular ultrasound imaging. At 1061 transducers/mm<sup>2</sup>, the PMUT array has a 10-20 times higher density than previous PMUT arrays realized to date. Aluminum nitride (AlN)-based PMUTs(More)
An accurate, low-power, and highly integrated solution for accurate assessment of body fat is presented that addresses a growing consumer interest in economical and easy-to-use solutions for monitoring personal health and fitness. Unlike the prevalent present solution that estimates body fat percentage from an impedance measurement integrated in a weight(More)
Ultrasound imaging uses costly bulk piezoelectric transducers and high voltage (200V+) electronics. Low-cost and low-voltage ultrasound transducers would enable many new applications in healthcare, biometrics, and personal health-monitoring. Here, we demonstrated short-range (~mm) and high-resolution (&lt;;100 &#x03BC;m) imaging based on piezoelectric(More)
This paper presents high fill-factor piezoelectric micromachined ultrasonic transducer (PMUT) arrays fabricated via a novel process using cavity SOI wafers. The simple three-mask fabrication process enables smaller diameter PMUTs (25 &#x03BC;m) and finer pitch than previous processes requiring through-wafer etching. PMUTs were fabricated with diameters from(More)
This paper presents a 591&#x00D7;438 DPI ultrasonic fingerprint sensor. The sensor is based on a piezoelectric micromachined ultrasonic transducer (PMUT) array that is bonded at wafer-level to complementary metal oxide semiconductor (CMOS) signal processing electronics to produce a pulse-echo ultrasonic imager on a chip. To meet the 500 DPI standard for(More)
Piezoelectric micromachined ultrasonic transducers (PMUTs) have the potential for broad bandwidth, thus enabling high resolution imaging. However, previous PMUTs had fractional bandwidths of only ~50% or smaller because of the thick multilayer PMUT structure. Here, we demonstrate broadband PZT PMUTs that achieve a 97% fractional bandwidth by utilizing a(More)
This work demonstrates short-range and high-resolution ultrasonic imaging using 8 MHz aluminum nitride (AlN) piezoelectric micromachined ultrasonic transducer (PMUT) arrays, which are compatible with complementary metal-oxide semiconductor circuitry and wafer-level mass manufacture. Because AlN has a low dielectric constant, the PMUTs have low capacitance(More)
This paper describes a single-chip 591&#x00D7;438 DPI ultrasonic fingerprint sensor. The sensor is based on a piezoelectric micromachined ultrasonic transducer (PMUT) array that is bonded at wafer-level to complementary metal oxide semiconductor (CMOS) signal processing electronics to produce a pulse-echo ultrasonic imager on a chip. To meet the 500 DPI(More)
A fully integrated 3-D ultrasonic fingerprint sensor-on-a-chip is presented. The device consists of a 110&#x00D7; 56 piezoelectric micromachined ultrasonic transducer (PMUT) array bonded at the wafer level to custom readout electronics fabricated in a 180-nm CMOS process with a HV (24 V) transistor option. With the 24 V driving signal strength, the sensor(More)