Agenda
EI Colloquium
- Friday, 3 July 2026
- 15:45-18:00
- Lecture Hall Chip
High-Performance PMUTs Enabled by Bilayer X-Cut Lithium Niobate by Xiaoxi Zhao
Xiaoxi Zhao
Abstract:
Piezoelectric micromachined ultrasonic transducers (PMUTs) are promising for compact ultrasound systems, including medical imaging, fingerprint sensing, range finding, etc. Compared with CMUTs, PMUTs can operate without a DC bias voltage, offer a more linear response, and are compatible with integrated microsystems. However, their transmit and receive sensitivities are still limited by material and device-design constraints. In this talk, I will present our recent work on PMUTs based on bilayer X-cut lithium niobate (LiNbO₃). By using the crystal orientation and bilayer structure of LiNbO₃, the device can more effectively convert membrane bending into electrical and acoustic signals. I will discuss the design concept, fabrication process, and characterization results, and show how this approach can be extended from single PMUTs to arrays for future integrated ultrasound systems.
Speaker Bio:
Xiaoxi Zhao is a PhD candidate in Microelectronics at Delft University of Technology, where his research focuses on piezoelectric micromachined ultrasonic transducers (PMUTs) based on lithium niobate. He specializes in MEMS modeling and design, microfabrication, PCB-level readout, and electrical, mechanical, and acoustic characterization of ultrasonic MEMS devices.
His PhD work explores high-performance PMUTs using bilayer X-cut lithium niobate, with the goal of improving transmit and receive sensitivity for compact integrated ultrasound systems. He has presented his research at leading international conferences, including Transducers, IEEE MEMS, and IEEE IUS, and was selected as a finalist for the Outstanding Young Researcher Award at Transducers 2025. Before joining TU Delft, he received his MSc in Microelectronics from South China University of Technology, where he worked on lithium-niobate-based MEMS infrared sensors.
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