Self-Curved Diaphragms By Stress Engineering For Highly Responsive pMUT

Tech ID: 24472 / UC Case 2015-050-0

Patent Status

Country Type Number Dated Case
United States Of America Published Application 20170170383 06/15/2017 2015-050
Patent Cooperation Treaty Published Application WO2015112452 07/30/2015 2015-050

Brief Description

Curved pMUTs, as developed at UC Berkeley, have been shown to have 2 orders of magnitude improvement over flat pMUTs as well as the capacity for post-processing tuning. However, it is desirable to improve production methods to make this innovation more commercially applicable.

To meet this challenge, investigators at Berkeley have developed a self-curved diaphragm process using stress engineering to produce highly responsive curved pMUTs. This diaphragm pMUT can boost 6X better performance compared to the flat diaphragm state-of-the-art pMUT. CMOS foundry-based process flow has produced self-curved diaphragms by engineering residual stress in thin films to construct molds for fabrication. Benefits of the invention include achieving silicon curved molds by patterning thin layers of stressed silicon nitride and silicon oxide layers on top of a silicon plate of a predetermined thickness.


- Ultrasonic gesture recognition
- Range finding
- Finger print identification
- Medical imaging and diagnosis
- Sensors in hand-held devices


- 95% wafer utilization
- Foundry-based CMOS process
- Frequency tuning to desired value
- Both low frequency and high frequency pMUT arrays

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