Electrical and mechanical properties of micromachined vacuum cavities

Jyrki Kiihamäki (Corresponding Author), Hannu Ronkainen, Ari Häärä, Tomi Mattila

Research output: Contribution to journalArticleScientificpeer-review

4 Citations (Scopus)

Abstract

This paper reports the measured electrical and mechanical properties of micromachined vacuum cavity resonators made on bonded silicon on insulator (SOI) wafers using the new plugup process. With this novel process it is possible to fabricate microelectromechanical devices without the attack of hydrofluoric acid against the aluminium metallisation during the sacrificial oxide layer etching. Another merit of the new process is its improved immunity to stiction.

The moving parts of the microresonator are constructed of single crystal silicon with very low internal stress. In surface micromachining the structures are typically made of CVD polysilicon, which has higher internal stress. Thus the mechanical properties of these resonators on SOI are governed by the elastic rigidity of the material used and the geometry of the structure which is affected by both design parameters and process variations.

The mechanical losses of the cavity structure are caused by the supports at edges of resonator and the acoustic damping. The pressure during LPCVD process used for sealing determines the pressure remaining in the cavity. With the plug-up process one can fabricate vacuum cavities on SOI substrates without deteriorating the silicon material properties or its surface quality. These cavities can be utilised for realization of a wide variety of single crystal micromechanical devices and in monolithical integration of SOI/MEMS and integrated circuits.

Original languageEnglish
Pages (from-to)195 - 198
Number of pages4
JournalPhysica Scripta
VolumeT114
DOIs
Publication statusPublished - 2004
MoE publication typeA1 Journal article-refereed
Event20th Nordic Semiconductor Meeting, NSM20 - Tampere, Finland
Duration: 25 Aug 200327 Aug 2003

Fingerprint

Electrical Properties
Silicon-on-insulator
Mechanical Properties
Vacuum
Cavity
electrical properties
mechanical properties
vacuum
cavities
Resonator
silicon
insulators
Single Crystal
Silicon
residual stress
Microresonators
Internal
resonators
Process Variation
Micromachining

Cite this

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title = "Electrical and mechanical properties of micromachined vacuum cavities",
abstract = "This paper reports the measured electrical and mechanical properties of micromachined vacuum cavity resonators made on bonded silicon on insulator (SOI) wafers using the new plugup process. With this novel process it is possible to fabricate microelectromechanical devices without the attack of hydrofluoric acid against the aluminium metallisation during the sacrificial oxide layer etching. Another merit of the new process is its improved immunity to stiction. The moving parts of the microresonator are constructed of single crystal silicon with very low internal stress. In surface micromachining the structures are typically made of CVD polysilicon, which has higher internal stress. Thus the mechanical properties of these resonators on SOI are governed by the elastic rigidity of the material used and the geometry of the structure which is affected by both design parameters and process variations. The mechanical losses of the cavity structure are caused by the supports at edges of resonator and the acoustic damping. The pressure during LPCVD process used for sealing determines the pressure remaining in the cavity. With the plug-up process one can fabricate vacuum cavities on SOI substrates without deteriorating the silicon material properties or its surface quality. These cavities can be utilised for realization of a wide variety of single crystal micromechanical devices and in monolithical integration of SOI/MEMS and integrated circuits.",
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Electrical and mechanical properties of micromachined vacuum cavities. / Kiihamäki, Jyrki (Corresponding Author); Ronkainen, Hannu; Häärä, Ari; Mattila, Tomi.

In: Physica Scripta, Vol. T114, 2004, p. 195 - 198.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Electrical and mechanical properties of micromachined vacuum cavities

AU - Kiihamäki, Jyrki

AU - Ronkainen, Hannu

AU - Häärä, Ari

AU - Mattila, Tomi

PY - 2004

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N2 - This paper reports the measured electrical and mechanical properties of micromachined vacuum cavity resonators made on bonded silicon on insulator (SOI) wafers using the new plugup process. With this novel process it is possible to fabricate microelectromechanical devices without the attack of hydrofluoric acid against the aluminium metallisation during the sacrificial oxide layer etching. Another merit of the new process is its improved immunity to stiction. The moving parts of the microresonator are constructed of single crystal silicon with very low internal stress. In surface micromachining the structures are typically made of CVD polysilicon, which has higher internal stress. Thus the mechanical properties of these resonators on SOI are governed by the elastic rigidity of the material used and the geometry of the structure which is affected by both design parameters and process variations. The mechanical losses of the cavity structure are caused by the supports at edges of resonator and the acoustic damping. The pressure during LPCVD process used for sealing determines the pressure remaining in the cavity. With the plug-up process one can fabricate vacuum cavities on SOI substrates without deteriorating the silicon material properties or its surface quality. These cavities can be utilised for realization of a wide variety of single crystal micromechanical devices and in monolithical integration of SOI/MEMS and integrated circuits.

AB - This paper reports the measured electrical and mechanical properties of micromachined vacuum cavity resonators made on bonded silicon on insulator (SOI) wafers using the new plugup process. With this novel process it is possible to fabricate microelectromechanical devices without the attack of hydrofluoric acid against the aluminium metallisation during the sacrificial oxide layer etching. Another merit of the new process is its improved immunity to stiction. The moving parts of the microresonator are constructed of single crystal silicon with very low internal stress. In surface micromachining the structures are typically made of CVD polysilicon, which has higher internal stress. Thus the mechanical properties of these resonators on SOI are governed by the elastic rigidity of the material used and the geometry of the structure which is affected by both design parameters and process variations. The mechanical losses of the cavity structure are caused by the supports at edges of resonator and the acoustic damping. The pressure during LPCVD process used for sealing determines the pressure remaining in the cavity. With the plug-up process one can fabricate vacuum cavities on SOI substrates without deteriorating the silicon material properties or its surface quality. These cavities can be utilised for realization of a wide variety of single crystal micromechanical devices and in monolithical integration of SOI/MEMS and integrated circuits.

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