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)

Abstract

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
DOIs
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
Volume2016-November
ISSN (Print)1948-5719
ISSN (Electronic)1948-5727

Other

Other2016 IEEE International Ultrasonics Symposium, IUS 2016
Country/TerritoryFrance
CityTours
Period16/9/1816/9/21

Keywords

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

ASJC Scopus subject areas

  • Acoustics and Ultrasonics

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