Imaging of simulated muscle based on single chip of AlN piezoelectric micromachined ultrasonic transducer

Abstract

Most of current portable B-mode medical imaging is based on traditional ultrasonic transducers (UTs) or capacitive micromachined ultrasonic transducers (cMUTs), both of them have defects that impede satisfying performance. Piezoelectric micromachined ultrasonic transducers (pMUTs) is a promising solution for portable/wearable B-mode imaging as alternative. This work demonstrates B-mode imaging of simulated muscle with an aluminum nitride (AlN) pMUT array for application of muscle disorder diagnosis. A 23×26 pMUT array with resonant frequency of 5 MHz (in oil) is fabricated based on cavity silicon on- -insulator (SOI) process. It has transmitting sensitivity of 3.6 kPa/V at 10 mm, receiving sensitivity of 1.1 μV/Pa and -6 dB bandwidth of 40% (in oil). Feasibility of muscle imaging based on pMUT is demonstrated by using muscle-like phantoms. Imaging results shows clear interfaces among layers, the axial and lateral resolution is 0.25 mm and 1.23 mm respectively. Furthermore, ex-vivo Bmode scans towards porcine tissues based on pMUT are firstly demonstrated. Different tissues including muscle, subcutaneous fat, fascia and hematoma is distinguished. The maximum imaging depth inside the porcine tissue is above 40 mm. These results demonstrate great potential of the pMUT array in muscle imaging.

Demonstration of MHz piezoelectric micromachined ultrasonic transducers array and its potential application for biomedical treatment

“…The transmit performance of this work demonstrates superior results compared to those presented in [28,29], primarily attributed to the larger total area. Despite having a smaller area than the [7], the utilization of ScAlN films and higher FFs in this work leads to improved transmit sensitivity. The PMUTs in [30] have good transmit performance but are lower than the transmit sensitivity of this work.…”

“…A fetal scan was carried out with their probe connected to a smartphone. Qu et al demonstrated B-mode imaging of simulated muscle with a piezoelectric micromachined ultrasound transducer (PMUT) array for application of muscle disorder diagnosis [7].…”

Recent Advances in Flexible Ultrasonic Transducers: From Materials Optimization to Imaging Applications

“…There has been an increased interest recently in the development of flexible US transducers using high performance piezoelectric thin film materials, such as AlN, ZnO and PZT, as shown in Figure 1 b [ 19 , 27 ]. These materials could be deposited on flexible substrates, such as thin metallic foils, to prepare flexible US transducers [ 16 , 18 , 19 , 27 , 33 ], due to the inherent physical flexibility of the film or the ultrathin thickness weakening its inherent stiffness. Vincenzo et al reported a flexible US transducer, which was based on micromembranes of piezoelectric AlN embedded between two Molybdenum electrodes on a Kapton substrate [ 27 ].…”

“…Recently, flexible US transducers with high performances in converting mechanical energy into electrical energy have attracted tremendous attention. Several groups have proposed some typical design strategies, such as attaching rigid piezoelectric material films to flexible substrates to construct flexible US transducers, directly fabricating flexible US transducers based on piezopolymers and flexible piezocomposites, embedding many rigid micromachined US transducer elements into flexible polymer substrates, and so on [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. The recent boom in the development of flexible electronic technology has also laid the foundation for the fabrication of higher performance flexible US transducers, especially for flexible array US transducers.…”

Noncontact human-machine interaction for air-writing with ultrasound technology

“…Piezoelectric micromachined ultrasonic transducers (pMUTs) manufactured using micro-electro-mechanical system (MEMS) technology offer many advantages, including low cost, miniaturization, and compatibility with microelectronics, while retaining the merits of the bulk piezoelectric ultrasonic transducers 33,34 . These pMUTs have been applied in various fields, including handheld devices for medical imaging [35][36][37] , fingerprint recognition 38,39 , wireless communication 40,41 , haptic feedback 42 .…”