Capacitive micromachined ultrasonic transducers

CMUTs – capacitive micromachined ultrasonic transducers – are MEMS based structures that can be used to transmit and receive acoustic signals in the ultrasonic range. They enable breakthrough applications for ultrasound, complementing conventional technology with advantages such as large bandwidth, easy fabrication of large arrays, and integration with driver circuitry: CMUT-on-CMOS.

CMUT ready for manufacturing

On top of these advantages, CMUT technology offers a lot of design freedom, enabling your custom ultrasound MEMS device. Our experience in design and processing of CMUT devices enables us to support your custom MEMS device requirements. CMUT technology is capable of operating in a wide range of conditions:

  • Temperature
    -40 °C up to 200 °C (up to 250 °C with application-specific design).
  • Pressure
    Up to 10 bar.
  • Abrasion resistance
    Protective stacks available for various applications, scratch- and impact-resistant.
  • Chemical robustness
    Resistant against substances like sulfuric acid (98%), ammonia water, sodium hydroxide, sodium oxalate, acetone, ethanol.

Exact device capabilities depend on design parameters and material choices.

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paul bekkers

Paul Bekkers
Business development manager

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Relevant for you

MEMS foundry High Tech Campus Eindhoven

Read more about our MEMS Foundry ›

Presentation CMUT and PMUT, Rob van Schaijk (PDF)

CMUT examples

Electronics assembly on CMUT wafer

Electronics assembly on CMUT wafer

Medical imaging CMUT array

Medical imaging CMUT array

Rollable CMUT array on flexible substrate

Rollable CMUT array on flexible substrate

Custom CMUT array with integrated flexible electrical connections

Custom CMUT array with integrated flexible electrical connections

Custom CMUT array on flexible foil

Custom CMUT array on flexible foil

Various CMUT layouts with flexible connections

Various CMUT layouts with flexible connections

What do you want to know about CMUT technology?

Imagine what could be possible with CMUT technology…

Are you curious about new sensors and transducer technology? Are you interested in learning more about the design and manufacturing of CMUT devices? Are you on the lookout for the newest technologies in town?

Our CMUT experts are here to think along with you and accelerate your innovation with clever new technology designs. We have been working on CMUT technology for over 10 years now, and we are ready to share our CMUT knowledge with you.

What is the principle of operation of a CMUT?


CMUT receiver - capacitive micromachined ultrasonic transducers


The basic element of a CMUT is a parallel-plate capacitor. One plate is fixed, the other plate is supported by a flexible membrane. In receiving mode, an ultrasonic wave causes membrane vibration and a change of capacitance, which can be detected.


CMUT transmitter - capacitive micromachined ultrasonic transducers


In transmitting mode, an alternating voltage is applied between the membrane and the substrate back plate. The resulting electrostatic forces cause vibration of the membrane, sending out ultrasound at the frequency of modulation.

 Key features of ultrasound MEMS designs

  • Frequency range from 500 kHz to 50 MHz
  • Large bandwidth: over 100% in immersion
  • Low mechanical coupling between elements, no crosstalk
  • Integration with ASIC: CMUT-on-CMOS
  • ROHS compliant, no toxic materials
  • Large range in numbers of CMUTs per array, array size, and array layout
  • Easily attainable miniaturization, leading to a small form factor

CMUT application areas

  • Medical imaging
  • Medical therapy (high intensity focused ultrasound HIFU)
  • ‘Smart’ medical instruments
  • Nondestructive testing
  • Ultrasonic flow metering
  • Short range distance measuring
  • Ultrasound microscopy
  • Particle & fluidic manipulation
  • Inkjet printing

MEMS Foundry & Micro Devices Facility

We are Philips Innovation Services and we operate a state-of-the-art 2,650 m² pure-play MEMS foundry in Eindhoven, the Netherlands. We offer in-house MEMS & Micro Devices services. At the MEMS Foundry and Micro Devices Facility we offer advanced prototyping, development and volume manufacturing services for capacitive micromachined ultrasonic transducers (CMUTs), both for components and for complete module assemblies.

Our CMUT technology enables high volume ultrasound transducer manufacturing and high levels of integration at a lower cost. You benefit from our expertise, built from developing and manufacturing a range of CMUT array devices. Our CMUT technology platform shortens design cycles and therefore your time-to-market. Partnering with Philips Innovation Services is the quickest way to obtain a reliable CMUT device.

More about our MEMS & Micro Devices expertise 

What sets us apart?

  • Device design, combining customer’s application know-how and over 10 years of CMUT experience.
  • Process development, state-of-the-art MEMS fabrication equipment, experienced engineering crew.
  • Development of customized driver ICs, including specification, design, test and industrialization support.
  • One-stop-shop, from device and process concept development to volume manufacturing, integration of electronics, and assembly services: one single partner for a custom CMUT device.
  • Pure-play MEMS foundry – for over 30 years we have been working for industry leaders with high confidentiality and IP protection demands.
  • High customer satisfaction, NPS score > 50% (4.5 on a 5-point scale).

MEMS Foundry services

MEMS Foundry services involved in the manufacturing of CMUT devices.

Check out our other MEMS applications

MEMS applications are many. Organ-on-a-chip for example, where a human organ is reproduced in its most elementary form: microelectromechanical systems device. Several applications stand out, because of their promise and our capabilities.

Relevant for you: MEMS & Micro Devices MEMS is our expertise

Sustainable competitive advantage through custom MEMS devices. Check out our services in the MEMS & Micro Devices key area of expertise.

News & events

Save the date! The next European MEMS & Sensors Summit will take place on 19-21 September 2018 in Grenoble, France.

Projects on ultrasound innovation awarded for future generation microfabrication technologies for ultrasound products and imaging catheters.

Presentation by technologist René Sanders about microfluidic device standardization and manufacturability at the Polymer Replication on Nanoscale conf.

Presentation by Dr. Jos Giesbers, Sr. Development Engineer & Technical Project Leader, focussed on unique to graphene applications for MEMS devices.

Contact us about capacitive micromachined ultrasonic transducers

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