Silicon-based surface micromachined interferometers for infrared wavelengths

Mikko Tuohiniemi

Silicon-based surface micromachined interferometers for infrared wavelengths

Julkaisun otsikon käännös: Piipohjaiset pintamikromekaaniset interferometrit infrapuna-aallonpituuksille

Mikko Tuohiniemi

Tutkimustuotos: Doctoral Thesis › Collection of Articles

Abstrakti

Fabry-Perot interferometri (FPI) on säädettävä optinen kaistanpäästösuodin. Mikromekaaninen (MEMS) toteutus mahdollistaa hyvin pienen interferometrin massatuotannon ja alhaisen yksikköhinnan. Teolliselle tuotannolle tyypillinen yksikköhinta olisi kymmenen euron luokkaa, koko muutama neliömilli ja tuotantomäärä miljoonia yksiköitä MEMS FPI on pienikokoisen spektrometrin avainkomponentti. Kaasujen transmissiospektrometriaa infrapuna-aalloilla käytetään esimerkiksi hiilivetyjen, hiilidioksidin ja monimutkaisempien orgaanisten yhdisteiden havaitsemiseen ja analyysiin. Sovellusalueita ovat muun muassa lääketiede, maatalous, moottoriajoneuvot, kaasuturvallisuus ja sisäilman laatu. Tässä työssä kehitettiin kapasitiivisesti säädettävä pintamikromekaaninen FPI termisen infrapunan ja keski-infrapunan aallonpituusalueille. Ainutlaatuinen piirre on Braggin peilin (DBR) rakenne: Si/ilma/Si. DBR perustuu pistemäisesti ankkuroituihin polypiikalvoihin vetojännityksessä. Pii-ilma DBR:n avulla savutetaan kapeampi päästökaista (parempi resoluutio), tasaisempi suorituskyky säädettäessä ja laajempi säätöalue. Työ pohjautuu VTT:n pintamikromekaanisen FPI:n teknologiaan, jolla saavutetaan laaja optinen alue ja joka osaltaan takaa tasaisen suorituskyvyn säädössä. Suorituskyvyn parannus perustuu työhypoteesiin pii-ilma DBR:n optisista ominaisuuksista. Sen lisäksi että konsepti todennettiin, huomattiin myös etuja rakenteen mekaanisessa käytöksessä. Väitöskirjan työssä on suunniteltu uuden mikromekaanisen interferometrin konsepti, rakenne ja valmistusmenetelmä. Valmistettiin lukuisia kiekkoja, joissa oli useita erilaisia FPI-mitoituksia ja malleja. Optinen ja sähköinen suorituskyky mitattiin kymmenistä näytteistä. Työn alkuvaiheessa valmistettiin myös testikiekkoeriä, joilla tutkittiin uhrikerrosten koostumusta, polypiin istutusta sekä DBR:n rakennetta, valmistusta ja suorituskykyä. Väitöskirjan julkaisut keskittyvät parhaiten toimineisiin rakenteisiin ja niiden valmistukseen. Varhaisiin testiajoihin ei julkaisuissa keskitytä muuten kuin toteamalla niiden johtopäätökset. Toimivan laitteen kehitystä tukevien valmistustestien tuloksista käsiteltiin yhdessä artikkelissa DBR ja toisessa istutuksen optimointi. Väitöskirja kattaa kehitystyön alkaen ideasta aina siihen asti kun konsepti osoitettiin toimivaksi. Työstä on rajattu pois kokeellinen tutkimus interfero-metrin suorituskyvystä ympäristökuormituksessa, joskin odotuksista on keskusteltu.

Julkaisun otsikon käännös	Piipohjaiset pintamikromekaaniset interferometrit infrapuna-aallonpituuksille
Alkuperäiskieli	Englanti
Pätevyys	Tohtorintutkinto
Myöntävä instituutio	Aalto-yliopisto
Ohjaaja	Franssila, Sami, Vastuuprofessori Franssila, Sami, Ohjaaja
Kustantaja	Aalto University
Painoksen ISBN	978-952-60-6177-1
Sähköinen ISBN	978-952-60-6178-8
Tila	Julkaistu - 2015
OKM-julkaisutyyppi	G5 Artikkeliväitöskirja

Tutkimusalat

mikromekaniikka
interferometri
pii

Pääsy asiakirjaan

http://urn.fi/URN:ISBN:978-952-60-6178-8Lisenssi: Määrittelemätön

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@phdthesis{94858d4db8a648afa9ad8e1b160da7a1,

title = "Silicon-based surface micromachined interferometers for infrared wavelengths",

abstract = "The Fabry-Perot interferometer (FPI) is a tunable optical band-pass filter. The realization with micro-electro mechanics (MEMS) technology enables high-volume production of miniature-size FPI at a low unit cost. Some ten-euro unit cost, few-millimeter square size, and millions of units fabrication volumes could characterize the industrial fabrication. The MEMS FPI is a key component of a miniature spectrometer. The gas-phase transmission infrared (IR) spectroscopy is applied in the detection and analysis of hydrocarbons, carbon dioxide and more complicated organic compounds. Application areas include medical, agriculture, automotive, gas security, and interior air quality, to name but a few. This work introduces a capacitively tunable surface-MEMS FPI for mid- and thermal IR. The unique feature is the Si/air/Si Bragg reflector (DBR) structure enabled by point-wise anchoring of tensile-stressed poly-Si films. The Si-air DBR enables narrower pass-band (better resolution) and more uniform tuning behavior over a wider tuning range. The founding technology of the MEMS FPI at VTT additionally provides a wide optical area and generally provides the uniform tuning performance. The improved performance is based on the work hypothesis of the Si-air DBR optical properties. Along with the proof of concept in this work, further benefits in the mechanical behavior of our structure were found. The work of the thesis covered the design of the concept, structure, and fabrication process for the novel MEMS FPI. Several wafers of multiple device designs were fabricated. Dozens of devices were characterized for the optical and electrical performance. In the early phase of the work, process-test wafer lots were fabricated for testing the sacrificial-layer composition, poly-Si implanting and the DBR structure, fabrication and performance. The publications, included in the thesis, concentrate on the dissemination of the designs of the best performance and of their structure and fabrication. The earlier test runs are not emphasized in the publications but the final conclusions are merely rephrased. A paper on the DBR demonstration, and another on the implanting optimization, report process-test results that supported the development of the fully functional device. The scope of the work covers the development from the idea until the proof of the concept. The scope is limited such that the devices reliability under environmental loads is discussed but not experimentally studied.",

keywords = "Fabry-Perot, MEMS, micromechanics, interferometer, silicon, mikromekaniikka, interferometri, pii, Fabry-Perot, MEMS, micromechanics, interferometer, silicon",

author = "Mikko Tuohiniemi",

year = "2015",

language = "English",

isbn = "978-952-60-6177-1",

series = "Aalto University publication series DOCTORAL DISSERTATIONS",

publisher = "Aalto University",

number = "54",

address = "Finland",

school = "Aalto University",

}

TY - BOOK

T1 - Silicon-based surface micromachined interferometers for infrared wavelengths

AU - Tuohiniemi, Mikko

PY - 2015

Y1 - 2015

N2 - The Fabry-Perot interferometer (FPI) is a tunable optical band-pass filter. The realization with micro-electro mechanics (MEMS) technology enables high-volume production of miniature-size FPI at a low unit cost. Some ten-euro unit cost, few-millimeter square size, and millions of units fabrication volumes could characterize the industrial fabrication. The MEMS FPI is a key component of a miniature spectrometer. The gas-phase transmission infrared (IR) spectroscopy is applied in the detection and analysis of hydrocarbons, carbon dioxide and more complicated organic compounds. Application areas include medical, agriculture, automotive, gas security, and interior air quality, to name but a few. This work introduces a capacitively tunable surface-MEMS FPI for mid- and thermal IR. The unique feature is the Si/air/Si Bragg reflector (DBR) structure enabled by point-wise anchoring of tensile-stressed poly-Si films. The Si-air DBR enables narrower pass-band (better resolution) and more uniform tuning behavior over a wider tuning range. The founding technology of the MEMS FPI at VTT additionally provides a wide optical area and generally provides the uniform tuning performance. The improved performance is based on the work hypothesis of the Si-air DBR optical properties. Along with the proof of concept in this work, further benefits in the mechanical behavior of our structure were found. The work of the thesis covered the design of the concept, structure, and fabrication process for the novel MEMS FPI. Several wafers of multiple device designs were fabricated. Dozens of devices were characterized for the optical and electrical performance. In the early phase of the work, process-test wafer lots were fabricated for testing the sacrificial-layer composition, poly-Si implanting and the DBR structure, fabrication and performance. The publications, included in the thesis, concentrate on the dissemination of the designs of the best performance and of their structure and fabrication. The earlier test runs are not emphasized in the publications but the final conclusions are merely rephrased. A paper on the DBR demonstration, and another on the implanting optimization, report process-test results that supported the development of the fully functional device. The scope of the work covers the development from the idea until the proof of the concept. The scope is limited such that the devices reliability under environmental loads is discussed but not experimentally studied.

AB - The Fabry-Perot interferometer (FPI) is a tunable optical band-pass filter. The realization with micro-electro mechanics (MEMS) technology enables high-volume production of miniature-size FPI at a low unit cost. Some ten-euro unit cost, few-millimeter square size, and millions of units fabrication volumes could characterize the industrial fabrication. The MEMS FPI is a key component of a miniature spectrometer. The gas-phase transmission infrared (IR) spectroscopy is applied in the detection and analysis of hydrocarbons, carbon dioxide and more complicated organic compounds. Application areas include medical, agriculture, automotive, gas security, and interior air quality, to name but a few. This work introduces a capacitively tunable surface-MEMS FPI for mid- and thermal IR. The unique feature is the Si/air/Si Bragg reflector (DBR) structure enabled by point-wise anchoring of tensile-stressed poly-Si films. The Si-air DBR enables narrower pass-band (better resolution) and more uniform tuning behavior over a wider tuning range. The founding technology of the MEMS FPI at VTT additionally provides a wide optical area and generally provides the uniform tuning performance. The improved performance is based on the work hypothesis of the Si-air DBR optical properties. Along with the proof of concept in this work, further benefits in the mechanical behavior of our structure were found. The work of the thesis covered the design of the concept, structure, and fabrication process for the novel MEMS FPI. Several wafers of multiple device designs were fabricated. Dozens of devices were characterized for the optical and electrical performance. In the early phase of the work, process-test wafer lots were fabricated for testing the sacrificial-layer composition, poly-Si implanting and the DBR structure, fabrication and performance. The publications, included in the thesis, concentrate on the dissemination of the designs of the best performance and of their structure and fabrication. The earlier test runs are not emphasized in the publications but the final conclusions are merely rephrased. A paper on the DBR demonstration, and another on the implanting optimization, report process-test results that supported the development of the fully functional device. The scope of the work covers the development from the idea until the proof of the concept. The scope is limited such that the devices reliability under environmental loads is discussed but not experimentally studied.

KW - Fabry-Perot

KW - MEMS

KW - micromechanics

KW - interferometer

KW - silicon

KW - mikromekaniikka

KW - interferometri

KW - pii

KW - Fabry-Perot

KW - MEMS

KW - micromechanics

KW - interferometer

KW - silicon

M3 - Doctoral Thesis

SN - 978-952-60-6177-1

T3 - Aalto University publication series DOCTORAL DISSERTATIONS

PB - Aalto University

ER -

Silicon-based surface micromachined interferometers for infrared wavelengths

Abstrakti

Tutkimusalat

Pääsy asiakirjaan

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