Characterization of AlN thin film piezoelectric coefficient d31 using Piezoelectric Micromachined Ultrasonic Transducers (PMUTs)

Development of piezoelectric micromachined ultrasonic transducers

Piezoelectric micromachined ultrasonic transducers (pMUTs) are an example of the application of MEMS technology to ultrasound generation and detection, which is expected to offer many advantages over conventional transducers. In this work, we investigate pMUTs through novel design and fabrication methods. A finite element (FE) model, with original tools to measure device performance, was develo...

Piezoelectric thin-film superlattices without using piezoelectric materials

In this paper we show that experimentally realizable apparently piezoelectric thin-film superlattices can be created from nonpiezoelectric materials provided an odd-order e.g., trilayer stacking sequence is used. The size-dependent mechanism of flexoelectricity, which couples gradients of strain to polarization, allows such a possibility. We present closed-form analytical expressions for the re...

Absolute Ultrasonic Measurements with Piezoelectric Transducers

The absolute calibration of a piezoelectric transducer refers to the determination of the relationship between the electrical and acoustical quantities for a transducer coupled to a solid. It is shown how a well-characterized ultrasonic system, consisting of source,structure and receiver can be used to make such measurements for transducers operating as sources or receivers. Results are given, ...

High Frequency and High Fill Factor Piezoelectric Micromachined Ultrasonic Transducers Based on Cavity Soi Wafers

This paper presents a high frequency and high fill factor piezoelectric micromachined ultrasonic transducer (PMUT) array, which is fabricated with a simple and CMOS compatible process based on commercially available cavity SOI wafers. This 2-mask process eliminates the need for through-wafer etching and enables 10× higher fill factor and thereby higher acoustic performance. PMUTs based on both ...

Micromachined piezoelectric ultrasonic transducer with ultra-wide frequency bandwidth