Microfabrication technologies for single-crystal silicon sensors

Päivi Sievilä

Microfabrication technologies for single-crystal silicon sensors

Julkaisun otsikon käännös: Yksikiteiseen piihin pohjautuvien antureiden mikrovalmistustekniikoita

Päivi Sievilä

Tutkimustuotos: Doctoral Thesis › Collection of Articles

Abstrakti

Korkealaatuisten materiaaliominaisuuksiensa vuoksi piillä on viimeisten vuosikymmenten ajan ollut keskeinen asema mikromekaniikan kehityksen kärjessä. Tässä työssä arvioidaan piin syövytysmenetelmien ominaispiirteitä ja niitä hyödyntämällä valmistetaan antureita, jotka ovat äärimmäisen herkkiä mekaanisten voimien havainnoinnissa. Vakiintuneempiin tekniikoihin yhdistellään esimerkiksi atomikerroskasvatusta (ALD) ja kohdistetun ionisuihkun (FIB) avulla tapahtuvaa työstämistä uudenlaisten toiminnallisten ominaisuuksien saavuttamiseksi. Väitöskirjassa keskitytään valmistamaan komponentteja yksikiteisestä piistä. Kehitetyt prosessit perustuvat olennaisilta osin anisotrooppiseen tetrametyyliammoniumhydroksidi (TMAH) -märkäsyövytykseen. Työssä tutkitaan materiaalien käyttäytymistä ottamalla huomioon lähtösubstraatteihin, seostukseen ja ohutkalvoihin liittyvät ominaisuudet sekä valmistuksen aikana että lopullisissa rakenteissa. Lisäksi selvitetään sisäisten jäännösjännitysten syntymekanismia mikromekaanisissa laitteissa. Saavutettuja tuloksia hyödyntämällä valmistettiin menestyksekkäästi mekaanisia antureita, joiden avulla voidaan havaita akustisia aaltoja suurella tarkkuudella. Silicon-on-insulator (SOI)-teknologian erityispiirteitä hyväksikäyttäen toteutettiin vapautettuja, kalvomaisia palkkirakenteita, jotka toimivat erittäin herkkinä mikrofoneina fotoakustisessa spektroskopiassa. Lisäksi ALD-ohutkalvopinnoituksesta todettiin olevan etua värähtelevien piiantureiden toiminnallisten ominaisuuksien muokkaamisessa. Koska yleisenä suuntauksena on tuottaa jatkuvasti yhä pienempikokoisia antureita, kehitettiin myös menetelmä, joka perustuu FIB-ioni-istutuksen käyttöön märkäsyövytysmaskina kolmiulotteisten nanorakenteiden valmistuksessa. Osa työssä valmistetuista fotoakustisista antureista on käytössä kaupallisissa kaasuanalysattoreissa. Laajemmasta näkökulmasta katsottuna erityisen merkittäviä ovat jännitysten hallintaan liittyvät tulokset, sillä niiden avulla pystytään parantamaan monenlaisten mikro- ja nanomekaanisten laitteiden tuotannon luotettavuutta. Kaikki työssä käytetyt menetelmät ovat yhteensopivia integroitujen piirien (IC) valmistuksen kanssa, mikä mahdollistaa kehitettyjen prosessien yhdistelemisen elektroniikkakomponentteihin sekä siirtämisen teolliseen tuotantoon.

Julkaisun otsikon käännös	Yksikiteiseen piihin pohjautuvien antureiden mikrovalmistustekniikoita
Alkuperäiskieli	Englanti
Pätevyys	Tohtorintutkinto
Myöntävä instituutio	Aalto-yliopisto
Valvoja/neuvonantaja	Tittonen, Ilkka, Vastuuprofessori
Kustantaja	Aalto University
Painoksen ISBN	978-952-60-5450-6
Sähköinen ISBN	978-952-60-5451-3
Tila	Julkaistu - 2013
OKM-julkaisutyyppi	G5 Artikkeliväitöskirja

Tutkimusalat

pii
SOI
mikromekaaniset laitteet
anturit
mikrovalmistustekniikat
märkäsyövytys
kohdistettu ionisuihku
seostus

Pääsy asiakirjaan

http://urn.fi/URN:ISBN:978-952-60-5451-3

Siteeraa tätä

@phdthesis{e33e76f2ef5046c3ac90d5d63bdc18f9,

title = "Microfabrication technologies for single-crystal silicon sensors",

abstract = "For decades, silicon as a high quality solid material has been playing a major role in developing state-of-the-art micromechanical sensors. In this work, the performance of silicon etching processes is evaluated, and utilized in creating devices for high precision sensing of mechanical forces. Emerging methods such as atomic layer deposition (ALD) and focused ion beam (FIB) processing are combined with established technologies in order to achieve extended functionalities. The thesis is focused on the fabrication of components from single crystal silicon. In the developed processes, anisotropic tetramethylammonium hydroxide (TMAH) wet etching has a central role. The material behavior related to substrate specifications, doping level, and the effects inherent to thin films, is studied both during the fabrication stage and in the final structures. Furthermore, the intrinsic residual stress generation in mechanical devices is investigated. The results were applied in successful production of mechanical sensors with superior accuracy in acoustic wave detection. The specific features of silicon-on-insulator (SOI) technology were utilized in the fabrication of released, membrane-type cantilevers that serve as highly sensitive microphones in photoacoustic spectroscopy. Moreover, ALD thin film coatings were shown to be advantageous in manipulating the functional properties of resonant silicon sensors. A step towards further device miniaturization was taken by using FIB implantation as a wet etching mask to realize 3D nanoscale structures. Some of the developed cantilever sensors have already been implemented in commercial photoacoustic gas analyzers. In a broader perspective, the achievements related to stress control in mechanical silicon structures are of great importance in reliable production of various micro- and nanomechanical systems. All the methods employed in this work are compatible with integrated circuit (IC) processing, which enables combining the developed processes with electronic chips and the adaptation to industrial manufacturing.",

keywords = "silicon, silicon-on-insulator SOI, micromechanical devices, sensors, microfabrication, wet etching, focused ion beam, doping, pii, SOI, mikromekaaniset laitteet, anturit, mikrovalmistustekniikat, m{\"a}rk{\"a}sy{\"o}vytys, kohdistettu ionisuihku, seostus, silicon, silicon-on-insulator SOI, micromechanical devices, sensors, microfabrication, wet etching, focused ion beam, doping",

author = "P{\"a}ivi Sievil{\"a}",

year = "2013",

language = "English",

isbn = "978-952-60-5450-6",

series = "Aalto University publication series DOCTORAL DISSERTATIONS",

publisher = "Aalto University",

number = "193",

address = "Finland",

school = "Aalto University",

}

TY - BOOK

T1 - Microfabrication technologies for single-crystal silicon sensors

AU - Sievilä, Päivi

PY - 2013

Y1 - 2013

N2 - For decades, silicon as a high quality solid material has been playing a major role in developing state-of-the-art micromechanical sensors. In this work, the performance of silicon etching processes is evaluated, and utilized in creating devices for high precision sensing of mechanical forces. Emerging methods such as atomic layer deposition (ALD) and focused ion beam (FIB) processing are combined with established technologies in order to achieve extended functionalities. The thesis is focused on the fabrication of components from single crystal silicon. In the developed processes, anisotropic tetramethylammonium hydroxide (TMAH) wet etching has a central role. The material behavior related to substrate specifications, doping level, and the effects inherent to thin films, is studied both during the fabrication stage and in the final structures. Furthermore, the intrinsic residual stress generation in mechanical devices is investigated. The results were applied in successful production of mechanical sensors with superior accuracy in acoustic wave detection. The specific features of silicon-on-insulator (SOI) technology were utilized in the fabrication of released, membrane-type cantilevers that serve as highly sensitive microphones in photoacoustic spectroscopy. Moreover, ALD thin film coatings were shown to be advantageous in manipulating the functional properties of resonant silicon sensors. A step towards further device miniaturization was taken by using FIB implantation as a wet etching mask to realize 3D nanoscale structures. Some of the developed cantilever sensors have already been implemented in commercial photoacoustic gas analyzers. In a broader perspective, the achievements related to stress control in mechanical silicon structures are of great importance in reliable production of various micro- and nanomechanical systems. All the methods employed in this work are compatible with integrated circuit (IC) processing, which enables combining the developed processes with electronic chips and the adaptation to industrial manufacturing.

AB - For decades, silicon as a high quality solid material has been playing a major role in developing state-of-the-art micromechanical sensors. In this work, the performance of silicon etching processes is evaluated, and utilized in creating devices for high precision sensing of mechanical forces. Emerging methods such as atomic layer deposition (ALD) and focused ion beam (FIB) processing are combined with established technologies in order to achieve extended functionalities. The thesis is focused on the fabrication of components from single crystal silicon. In the developed processes, anisotropic tetramethylammonium hydroxide (TMAH) wet etching has a central role. The material behavior related to substrate specifications, doping level, and the effects inherent to thin films, is studied both during the fabrication stage and in the final structures. Furthermore, the intrinsic residual stress generation in mechanical devices is investigated. The results were applied in successful production of mechanical sensors with superior accuracy in acoustic wave detection. The specific features of silicon-on-insulator (SOI) technology were utilized in the fabrication of released, membrane-type cantilevers that serve as highly sensitive microphones in photoacoustic spectroscopy. Moreover, ALD thin film coatings were shown to be advantageous in manipulating the functional properties of resonant silicon sensors. A step towards further device miniaturization was taken by using FIB implantation as a wet etching mask to realize 3D nanoscale structures. Some of the developed cantilever sensors have already been implemented in commercial photoacoustic gas analyzers. In a broader perspective, the achievements related to stress control in mechanical silicon structures are of great importance in reliable production of various micro- and nanomechanical systems. All the methods employed in this work are compatible with integrated circuit (IC) processing, which enables combining the developed processes with electronic chips and the adaptation to industrial manufacturing.

KW - silicon

KW - silicon-on-insulator SOI

KW - micromechanical devices

KW - sensors

KW - microfabrication

KW - wet etching

KW - focused ion beam

KW - doping

KW - pii

KW - SOI

KW - mikromekaaniset laitteet

KW - anturit

KW - mikrovalmistustekniikat

KW - märkäsyövytys

KW - kohdistettu ionisuihku

KW - seostus

KW - silicon

KW - silicon-on-insulator SOI

KW - micromechanical devices

KW - sensors

KW - microfabrication

KW - wet etching

KW - focused ion beam

KW - doping

M3 - Doctoral Thesis

SN - 978-952-60-5450-6

T3 - Aalto University publication series DOCTORAL DISSERTATIONS

PB - Aalto University

ER -

Microfabrication technologies for single-crystal silicon sensors

Abstrakti

Tutkimusalat

Pääsy asiakirjaan

Sormenjälki

Siteeraa tätä