Thin film technology for chemical sensors

Antti J. Niskanen

Thin film technology for chemical sensors

Julkaisun otsikon käännös: Ohutkalvoteknologian käyttö kemiallisissa antureissa

Antti J. Niskanen

Tutkimustuotos: Doctoral Thesis › Collection of Articles

Abstrakti

Mikrovalmistus- ja ohutkalvoteknologioita hyödynnettiin pienikokoisten kemiallisten anturien valmistuksessa. Työssä kehitettiin kahdenlaisia antureita: kuumien elektronien aiheuttamaan elektrokemiluminesenssiin perustuvia antureita, sekä atomikerroskasvatuksella (ALD:llä) valmistettua tinadioksidiohutkalvoa käyttävä mikrovalmistettu kaasuanturi. Kuumien elektronien aiheuttamaan elektrokemiluminesenssiin perustuvassa anturissa on samalle sirulle integroitu sekä ohuella eristekalvolla päällystetty työelektrodi, että platinaohutkalvosta valmistettu vastaelektrodi. Sirulle on myös valmistettu kahdenlaisia rakenteita nesteen käsittelyä varten: polydimetyylisiloksaanista (PDMS:stä) valmistettuja suljettuja nestekammioita, sekä hydrofobisia rakenteita sirun pinnalla. Useita materiaaleja kokeiltiin työelektrodeissa, tavoitteena löytää elektrokemiluminesenssin kannalta tehokkain elektrodirakenne. Näitä materiaaleja käytettiin integroiduissa elektrodisiruissa, joita valmistettiin sekä pii- että lasikiekoille. Useita eri elektrodigeometrioita testattiin erilaisten nesteenkäsittelyrakenteiden kanssa, ja parhailla geometrioilla saavutettiin alle nanomolaarisia herkkyyksiä. Muovisille alustoille valmistetuista komponenteista esitetään myös alustavia tuloksia. Yhteenveto-osassa esitetään uusimpia, vielä julkaisemattomia tuloksia PDMS:stä valmistetun nestekammion pinnan palauttamisesta hydrofiiliseksi. PDMS:n pinta palautuu luonnostaan hydrofobiseksi, mikä estää kammion täyttymisen pelkällä kapillaarivoimalla. Tässä esitetyllä plasmakäsittelyllä PDMS-kammion saa täyttymään pelkällä kapillaarivoimalla myös pitkän säilytyksen jälkeen. Kaasuanturikomponentti on mikrolämpölevytyyppinen, ja siinä käytetään tinadioksidia kaasuherkkänä materiaalina. Tinadioksidi on valmistettu atomikerroskasvatuksella ensimmäistä kertaa tämäntyyppisessä anturissa. Tämän mahdollistamiseksi komponentin valmistusprosessissa tarvittiin useita erikoisia ratkaisuja. Lisäksi, mikrolämpölevyssä käytettiin poikkeuksellisia materiaaleja ja menetelmiä mahdollistamaan nopea valmistus käytettävissä olevilla laitteilla. Valmiilla komponenteilla mitattiin nopeita vasteaikoja eri kaasuille, täydellistä palautumista altistuksen jälkeen, sekä vakaita ominaisuuksia lyhyellä aikavälillä. Tämä osoittaa ALD-menetelmän sopivuuden kaasuanturikäytössä.

Julkaisun otsikon käännös	Ohutkalvoteknologian käyttö kemiallisissa antureissa
Alkuperäiskieli	Englanti
Pätevyys	Tohtorintutkinto
Myöntävä instituutio	Aalto-yliopisto
Valvoja/neuvonantaja	Kuivalainen, Pekka, Vastuuprofessori Franssila, Sami, Ohjaaja
Kustantaja	Aalto University
Painoksen ISBN	978-952-60-4450-7
Sähköinen ISBN	978-952-60-4451-4
Tila	Julkaistu - 2011
OKM-julkaisutyyppi	G5 Tohtorinväitöskirja (artikkeli)

Tutkimusalat

ultraohuet eristekalvot
elektrokemiluminesenssi
mikrovalmistettu kaasuanturi
atomikerroskasvatus

Pääsy asiakirjaan

http://urn.fi/URN:ISBN:978-952-60-4451-4

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title = "Thin film technology for chemical sensors",

abstract = "Microfabrication and thin film technologies were applied in the fabrication of miniaturized chemical sensors. Two types of devices were developed: an electrochemiluminescence device utilizing tunnel-emitted hot electrons, and a microhotplate semiconductor gas sensor with an atomic layer deposited (ALD) tin dioxide sensing film. The hot electron-induced electrochemiluminescence (HECL) device is an integrated microelectrode device that combines an insulator-covered working electrode and a platinum counter electrode on a single chip. Two types of fluidic systems were integrated on the same type of electrode chip: either an enclosed sample chamber made of polydimethylsiloxane (PDMS) elastomer, or hydrophobic sample confinement on the chip surface. Different metals were tested as the working electrode, and different types of insulator films made by various methods were tested as the tunneling dielectric, to determine the optimal working electrode structures for HECL. These were then used in the integrated microelectrode devices, which were fabricated on silicon and glass substrates. A variety of electrode geometries were tested with the different fluidic systems, and sub-nanomolar sensitivity and wide dynamic range were demonstrated with the best devices. Ongoing work with polymeric substrates is briefly presented. In the review, latest results are presented on the restoration of the hydrophilic properties of enclosed PDMS microfluidic channels. While a PDMS surface quickly reverts to its naturally hydrophobic state, thus preventing capillary filling, this plasma treatment enables capillary filling even after extended periods of storage.The gas sensor is a microhotplate (MHP) device, utilizing a tin dioxide sensing layer deposited by ALD for the first time in a MHP sensor. Unconventional solutions were developed for the fabrication sequence to accommodate the demands of the deposition method. Also, metallizations and intermetal dielectrics not commonly used in MHP devices were tested to enable rapid processing of prototype devices with available methods and equipment. Fast response to various analyte gases, as well as good recovery and short-term stability were observed, demonstrating the potential of ALD tin dioxide films in gas sensor applications.",

keywords = "ultrathin insulating films, electrochemiluminescence, microhotplate gas sensor, atomic layer deposition, ultraohuet eristekalvot, elektrokemiluminesenssi, mikrovalmistettu kaasuanturi, atomikerroskasvatus, ultrathin insulating films, electrochemiluminescence, microhotplate gas sensor, atomic layer deposition",

author = "Niskanen, {Antti J.}",

year = "2011",

language = "English",

isbn = "978-952-60-4450-7",

series = "Aalto University publication series DOCTORAL DISSERTATIONS",

publisher = "Aalto University",

number = "146",

address = "Finland",

school = "Aalto University",

}

TY - THES

T1 - Thin film technology for chemical sensors

AU - Niskanen, Antti J.

PY - 2011

Y1 - 2011

N2 - Microfabrication and thin film technologies were applied in the fabrication of miniaturized chemical sensors. Two types of devices were developed: an electrochemiluminescence device utilizing tunnel-emitted hot electrons, and a microhotplate semiconductor gas sensor with an atomic layer deposited (ALD) tin dioxide sensing film. The hot electron-induced electrochemiluminescence (HECL) device is an integrated microelectrode device that combines an insulator-covered working electrode and a platinum counter electrode on a single chip. Two types of fluidic systems were integrated on the same type of electrode chip: either an enclosed sample chamber made of polydimethylsiloxane (PDMS) elastomer, or hydrophobic sample confinement on the chip surface. Different metals were tested as the working electrode, and different types of insulator films made by various methods were tested as the tunneling dielectric, to determine the optimal working electrode structures for HECL. These were then used in the integrated microelectrode devices, which were fabricated on silicon and glass substrates. A variety of electrode geometries were tested with the different fluidic systems, and sub-nanomolar sensitivity and wide dynamic range were demonstrated with the best devices. Ongoing work with polymeric substrates is briefly presented. In the review, latest results are presented on the restoration of the hydrophilic properties of enclosed PDMS microfluidic channels. While a PDMS surface quickly reverts to its naturally hydrophobic state, thus preventing capillary filling, this plasma treatment enables capillary filling even after extended periods of storage.The gas sensor is a microhotplate (MHP) device, utilizing a tin dioxide sensing layer deposited by ALD for the first time in a MHP sensor. Unconventional solutions were developed for the fabrication sequence to accommodate the demands of the deposition method. Also, metallizations and intermetal dielectrics not commonly used in MHP devices were tested to enable rapid processing of prototype devices with available methods and equipment. Fast response to various analyte gases, as well as good recovery and short-term stability were observed, demonstrating the potential of ALD tin dioxide films in gas sensor applications.

AB - Microfabrication and thin film technologies were applied in the fabrication of miniaturized chemical sensors. Two types of devices were developed: an electrochemiluminescence device utilizing tunnel-emitted hot electrons, and a microhotplate semiconductor gas sensor with an atomic layer deposited (ALD) tin dioxide sensing film. The hot electron-induced electrochemiluminescence (HECL) device is an integrated microelectrode device that combines an insulator-covered working electrode and a platinum counter electrode on a single chip. Two types of fluidic systems were integrated on the same type of electrode chip: either an enclosed sample chamber made of polydimethylsiloxane (PDMS) elastomer, or hydrophobic sample confinement on the chip surface. Different metals were tested as the working electrode, and different types of insulator films made by various methods were tested as the tunneling dielectric, to determine the optimal working electrode structures for HECL. These were then used in the integrated microelectrode devices, which were fabricated on silicon and glass substrates. A variety of electrode geometries were tested with the different fluidic systems, and sub-nanomolar sensitivity and wide dynamic range were demonstrated with the best devices. Ongoing work with polymeric substrates is briefly presented. In the review, latest results are presented on the restoration of the hydrophilic properties of enclosed PDMS microfluidic channels. While a PDMS surface quickly reverts to its naturally hydrophobic state, thus preventing capillary filling, this plasma treatment enables capillary filling even after extended periods of storage.The gas sensor is a microhotplate (MHP) device, utilizing a tin dioxide sensing layer deposited by ALD for the first time in a MHP sensor. Unconventional solutions were developed for the fabrication sequence to accommodate the demands of the deposition method. Also, metallizations and intermetal dielectrics not commonly used in MHP devices were tested to enable rapid processing of prototype devices with available methods and equipment. Fast response to various analyte gases, as well as good recovery and short-term stability were observed, demonstrating the potential of ALD tin dioxide films in gas sensor applications.

KW - ultrathin insulating films

KW - electrochemiluminescence

KW - microhotplate gas sensor

KW - atomic layer deposition

KW - ultraohuet eristekalvot

KW - elektrokemiluminesenssi

KW - mikrovalmistettu kaasuanturi

KW - atomikerroskasvatus

KW - ultrathin insulating films

KW - electrochemiluminescence

KW - microhotplate gas sensor

KW - atomic layer deposition

M3 - Doctoral Thesis

SN - 978-952-60-4450-7

T3 - Aalto University publication series DOCTORAL DISSERTATIONS

PB - Aalto University

ER -

Thin film technology for chemical sensors

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