Performance analysis and design of FET-embedded capacitive micromachined ultrasonic transducer (CMUT)

Seung Geun Jung, Jinsik Kim, Kyo Seon Hwang, Hyun Yong Yu, Byung Chul Lee

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)


In this paper, we present design guideline and simulation results of capacitive micromachined ultrasonic transducer (CMUT) embedded field effect transistor (FET) for high frequency mode operation. The CMUT-FET consists of a mechanical CMUT part and an electrical sensing FET part. The device has a characteristic of a shared gate dielectric between a CMUT and an FET; hence, the gate capacitance change in the CMUT part can be reflected to the FET current as pressure changes. With an FET's current amplifying characteristic, the CMUT-FET makes it possible to achieve higher sensitivity and high resonant frequency with smaller element pitch and smaller active cell area than existing CMUTs. Combination of a 3-D finite element analysis (FEA) model of the CMUT part and a commercial technology computer aided design (TCAD) simulation of the FET device was used for inspection of the CMUT-FET device performance. In the 3-D FEA simulation, we focused on investigating pull-in voltage and electrical potential of a rectangular CMUT plate which have 20MHz resonant frequency in immersion with different dimensions. The FET part simulation was performed with variation of gate oxide thickness, source/drain doping concentration, channel doping concentration, substrate doping concentration. We combined data and inspected overall device performance with pressure variation at specific gate voltage and optimized the factor above-mentioned to get high sensitivity. Simulation results show that the optimized model has the collapse voltage of 13.4V and the pressure sensitivity of 11.34μA/Pa at gate voltage of 11V.

Original languageEnglish
Title of host publication2016 IEEE International Ultrasonics Symposium, IUS 2016
PublisherIEEE Computer Society
ISBN (Electronic)9781467398978
Publication statusPublished - 2016 Nov 1
Event2016 IEEE International Ultrasonics Symposium, IUS 2016 - Tours, France
Duration: 2016 Sept 182016 Sept 21

Publication series

NameIEEE International Ultrasonics Symposium, IUS
ISSN (Print)1948-5719
ISSN (Electronic)1948-5727


Other2016 IEEE International Ultrasonics Symposium, IUS 2016

Bibliographical note

Publisher Copyright:
© 2016 IEEE.

Copyright 2016 Elsevier B.V., All rights reserved.


  • 3-D FEA simulation
  • CMUT
  • FET
  • High-frequency

ASJC Scopus subject areas

  • Acoustics and Ultrasonics


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