A Novel Method for cMUT fabrication

Jaakko Saarilahti; Hannu Kattelus; Ari Häärä; Martti Blomberg

A Novel Method for cMUT fabrication

Jaakko Saarilahti, Hannu Kattelus, Ari Häärä, Martti Blomberg

Research output: Contribution to conference › Conference article › Scientific › peer-review

Abstract

We present a novel surface micromachining process, where the top electrodes of the cMUTs (capacitive Micromachined Ultrasonic Transducer) are made-up of a combination of silicon nitride and porous polysilicon. This construction gives many advantages over the fabrication processes reported in the past. Our fabrication process contains an original method for HF etching of the sacrificial oxide layer through porous silicon, which technique seems to make the sealing process easier and improve the process quality. Also presented is a complete examination of the LPCVD low tensile silicon nitride deposition process, as the silicon nitride is used as part of the cMUT top layer. We have considered the mechanical stress, deposition rate, refractive index, etch rate and chemical composition of the LPCVD silicon nitride membranes as a function of the deposition parameters. The effects of the properties of the top membrane LPCVD silicon nitride to the cMUT characteristics are presented.

Original language	English
Publication status	Published - 2003
MoE publication type	Not Eligible
Event	3rd International Workshop on Micromachined Ultrasonic Transducers - Lausanne, Switzerland Duration: 26 Jun 2003 → 27 Jun 2003

Conference

Conference	3rd International Workshop on Micromachined Ultrasonic Transducers
Country/Territory	Switzerland
City	Lausanne
Period	26/06/03 → 27/06/03

Keywords

cMUT, Capacitive Micromachined Ultrasonic Transducers
ultrasonics

Cite this

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title = "A Novel Method for cMUT fabrication",

abstract = "We present a novel surface micromachining process, where the top electrodes of the cMUTs (capacitive Micromachined Ultrasonic Transducer) are made-up of a combination of silicon nitride and porous polysilicon. This construction gives many advantages over the fabrication processes reported in the past. Our fabrication process contains an original method for HF etching of the sacrificial oxide layer through porous silicon, which technique seems to make the sealing process easier and improve the process quality. Also presented is a complete examination of the LPCVD low tensile silicon nitride deposition process, as the silicon nitride is used as part of the cMUT top layer. We have considered the mechanical stress, deposition rate, refractive index, etch rate and chemical composition of the LPCVD silicon nitride membranes as a function of the deposition parameters. The effects of the properties of the top membrane LPCVD silicon nitride to the cMUT characteristics are presented.",

keywords = "cMUT, Capacitive Micromachined Ultrasonic Transducers, ultrasonics",

author = "Jaakko Saarilahti and Hannu Kattelus and Ari H{\"a}{\"a}r{\"a} and Martti Blomberg",

note = "Project code: T2SU00196 invited talk No bibliographic info about proceedings publication found; 3rd International Workshop on Micromachined Ultrasonic Transducers ; Conference date: 26-06-2003 Through 27-06-2003",

year = "2003",

language = "English",

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TY - CONF

T1 - A Novel Method for cMUT fabrication

AU - Saarilahti, Jaakko

AU - Kattelus, Hannu

AU - Häärä, Ari

AU - Blomberg, Martti

N1 - Project code: T2SU00196 invited talk No bibliographic info about proceedings publication found

PY - 2003

Y1 - 2003

N2 - We present a novel surface micromachining process, where the top electrodes of the cMUTs (capacitive Micromachined Ultrasonic Transducer) are made-up of a combination of silicon nitride and porous polysilicon. This construction gives many advantages over the fabrication processes reported in the past. Our fabrication process contains an original method for HF etching of the sacrificial oxide layer through porous silicon, which technique seems to make the sealing process easier and improve the process quality. Also presented is a complete examination of the LPCVD low tensile silicon nitride deposition process, as the silicon nitride is used as part of the cMUT top layer. We have considered the mechanical stress, deposition rate, refractive index, etch rate and chemical composition of the LPCVD silicon nitride membranes as a function of the deposition parameters. The effects of the properties of the top membrane LPCVD silicon nitride to the cMUT characteristics are presented.

AB - We present a novel surface micromachining process, where the top electrodes of the cMUTs (capacitive Micromachined Ultrasonic Transducer) are made-up of a combination of silicon nitride and porous polysilicon. This construction gives many advantages over the fabrication processes reported in the past. Our fabrication process contains an original method for HF etching of the sacrificial oxide layer through porous silicon, which technique seems to make the sealing process easier and improve the process quality. Also presented is a complete examination of the LPCVD low tensile silicon nitride deposition process, as the silicon nitride is used as part of the cMUT top layer. We have considered the mechanical stress, deposition rate, refractive index, etch rate and chemical composition of the LPCVD silicon nitride membranes as a function of the deposition parameters. The effects of the properties of the top membrane LPCVD silicon nitride to the cMUT characteristics are presented.

KW - cMUT, Capacitive Micromachined Ultrasonic Transducers

KW - ultrasonics

M3 - Conference article

T2 - 3rd International Workshop on Micromachined Ultrasonic Transducers

Y2 - 26 June 2003 through 27 June 2003

ER -

A Novel Method for cMUT fabrication

Abstract

Conference

Keywords

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