Capacitive micromachined ultrasonic transducers


What are CMUTs?

CMUTs – capacitive micromachined ultrasonic transducers – is a breakthrough ultrasound technology. CMUT 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 technology in a diverse range of industries such as medical, microscopy, inkjet printin and testing among others. Compared to conventional technology, CMUT ultrasound transducers convey numerous advantages such as large bandwidth, easy fabrication of large arrays, and integration with driver circuitry: CMUT-on-CMOS.

Advantages of CMUT technology in 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. Our CMUT experts with over 10 years of experience are here to think along with you and make innovation work with clever new technology designs.


Direct contact

paul bekkers

Paul Bekkers
Business development manager

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Relevant news 

Read more about ultrasound innovation project gets ECSEL award ›

What is the principle of operation of a CMUT?


CMUT receiver - capacitive micromachined ultrasonic transducers


The basic element of a CMUT array 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 CMUT transducers

  • 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

CMUT examples

CMUTs - Capacitive Micromachined Ultrasonic Transducers can be used in a series of industries and applications. Here you see some examples of CMUT arrays that we've developed together with our partners.

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

Philips Innovation Services - with over 10 years of experience in CMUT technology

Imagine what could be possible with CMUT technology. Are you curious about new CMUT 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.

Our CMUT experts deliver 

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


Contact a CMUT expert now

Learn more about CMUT and PMUT in medical ultrasound imaging

Download the CMUT and PMUT presentation

Explore the possibilities of CMUT and PMUT, a new technology platform for medical ultrasound


Presentation CMUT and PMUT, Rob van Schaijk (PDF)

Interested in additional MEMS Foundry services?

We offer several MEMS Foundry services that are also involved in the manufacturing of CMUT devices. Check out our additional services here as well as other relevant MEMS applications.

Relevant for you: MEMS & Micro Devices 

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. Check out our services in the MEMS & Micro Devices key area of expertise.

Contact us about capacitive micromachined ultrasonic transducers

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