Plasma-enhanced atomic layer deposition of aluminum nitride : characteristics and applications

Heli Seppänen

Plasma-enhanced atomic layer deposition of aluminum nitride : characteristics and applications

Julkaisun otsikon käännös: Alumiininitridin plasma-avusteinen atomikerroskasvatus : ominaisuudet ja sovellukset

Heli Seppänen

Elektroniikan ja nanotekniikan laitos

Tutkimustuotos: Doctoral Thesis › Collection of Articles

Abstrakti

Plasma-avusteisella atomikerroskasvatuksella (eng. plasma-enhanced atomic layer deposition, PEALD) on useita etuja verrattuna moniin ohutkalvojen kasvatustekniikoihin, kuten esimerkiksi monimutkaisten rakenteiden tasainen pinnoittaminen. Huonolaatuinen kiteisyys on kuitenkin PEALD:lla kasvatettujen alumiininitridiohutkalvojen (AlN) heikkous, mikä on estänyt niiden käytön monissa sovelluksissa. Tässä väitöskirjassa tutkittiin PEALD-prosessia, jolla voitaisiin saavuttaa parempi kidelaatu AlN-ohutkalvoihin. Tutkitussa prosessissa PEALD-jaksoon on lisätty ylimääräinen plasmavaihe, atomikerroshehkutus (eng. atomic layer annealing, ALA). Väitöskirjan tulokset on jaettu uuden AlN-materiaalin ominaisuuksiin sekä PEALD ALA AlN - ja PEALD AlN -ohutkalvojen käyttöön erinäisissä sovelluksissa. PEALD ALA -prosessilla saavutettiin parempi stoikiometria, kiteisyys sekä c-akselin mukainen suuntautuminen AlN:lle. Lisäksi materiaalissa on vähemmän hiili- ja vetyepäpuhtauksia, mutta enemmän happiepäpuhtauksia. Hehkutus tyhjiössä korkeassa lämpötilassa kasvatuksen jälkeen poistaa epäpuhtauksia kalvosta, muttei paranna kiteisyyttä. Pinnoitettavan substraatin kiteisyys vaikuttaa myös kalvon kidelaatuun, ja sillä voi edistää AlN:n kasvua haluttuun kiderakenteeseen. Mittauksissa todettiin ALA AlN:n olevan pietsosähköinen kasvatettuna alumiinille. Lisäksi se kasvaa kiteisenä pystysuorille sivuseinille. PEALD ALA AlN:n käyttö siirtymäkerroksena uudelleenkasvatettavaksi metalliorgaanista kemiallista kaasufaasipinnoitusta käyttäen osoitettiin onnistuneesti. PEALD AlN todettiin toimivaksi piin pintapassivointimateriaaliksi. Kalvo passivoi pinnan, ja pisimmät varauksenkuljettajien elinajat saatiin korkeampaa kasvatuslämpötilaa käyttämällä sekä hehkutuksen että nopean kuumennuksen (engl. firing) yhdistelmää kasvatuksen jälkeisenä lämpökäsittelynä.

Julkaisun otsikon käännös	Alumiininitridin plasma-avusteinen atomikerroskasvatus : ominaisuudet ja sovellukset
Alkuperäiskieli	Englanti
Pätevyys	Tohtorintutkinto
Myöntävä instituutio	Aalto-yliopisto
Valvoja/neuvonantaja	Lipsanen, Harri, Vastuuprofessori Suihkonen, Sami, Ohjaaja Kauppinen, Christoffer, Ohjaaja
Kustantaja	Aalto University
Painoksen ISBN	978-952-64-1619-9
Sähköinen ISBN	978-952-64-1620-5
Tila	Julkaistu - 2024
OKM-julkaisutyyppi	G5 Artikkeliväitöskirja

Tutkimusalat

plasma-avusteinen atomikerroskasvatus
AlN
atomikerroshehkutus
ohutkalvot

Pääsy asiakirjaan

http://urn.fi/URN:ISBN:978-952-64-1620-5

OtaNano
Rissanen, A. (Manager)
Aalto-yliopisto
Laitteistot/tilat: Facility
OtaNano Nanofab
Repo, P. (Manager) & Rissanen, A. (Other)
OtaNano
Laitteistot/tilat: Facility
OtaNano Nanomikroskopiakeskus
Seitsonen, J. (Manager) & Rissanen, A. (Other)
OtaNano
Laitteistot/tilat: Facility

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@phdthesis{bf484381e6dc4a06a9eb9ae8cb78d1ee,

title = "Plasma-enhanced atomic layer deposition of aluminum nitride : characteristics and applications",

abstract = "Plasma-enhanced atomic layer deposition (PEALD) offers a variety of advantages over other thin film growth techniques, such as conformal coverage of complex surface structures. However, low crystallinity has been a drawback for PEALD aluminum nitride (AlN) thin films, which makes it impossible to use in many applications. In this thesis, a process for reaching a higher quality AlN grown with PEALD was studied. The process included an added plasma step into the PEALD cycle, atomic layer annealing (ALA). The results of this thesis are divided into material characteristics of the improved PEALD ALA AlN and use of PEALD ALA AlN and PEALD AlN thin films in diverse applications. AlN grown with the PEALD ALA process has improved stoichiometry, crystallinity, and c-axis orientation, and contained less carbon and hydrogen impurities. Amount of oxygen impurities has increased. Post deposition annealing at high temperature in vacuum reduced impurities but did not improve the crystallinity further. The substrate also has an impact on the obtained crystal quality of the film and could aid the AlN film to achieve the preferred structure. The ALA AlN was measured to be piezoelectric when deposited on an aluminum substrate. In addition, ALA AlN grows crystalline on vertical sidewalls. The use of PEALD ALA AlN as a transition layer for further metalorganic chemical vapor deposition regrowth was demonstrated successfully. Silicon surface passivation was demonstrated with PEALD AlN. The film provides passivation for the surface and the highest carrier lifetime was obtained with higher deposition temperature and a combination of annealing and firing as a postdeposition heat treatment.",

keywords = "plasma-enhanced atomic layer deposition, AlN, atomic layer annealing, thin films, plasma-avusteinen atomikerroskasvatus, AlN, atomikerroshehkutus, ohutkalvot, plasma-enhanced atomic layer deposition, AlN, atomic layer annealing, thin films",

author = "Heli Sepp{\"a}nen",

year = "2024",

language = "English",

isbn = "978-952-64-1619-9",

series = "Aalto University publication series DOCTORAL THESES",

publisher = "Aalto University",

number = "6",

address = "Finland",

school = "Aalto University",

}

TY - BOOK

T1 - Plasma-enhanced atomic layer deposition of aluminum nitride : characteristics and applications

AU - Seppänen, Heli

PY - 2024

Y1 - 2024

N2 - Plasma-enhanced atomic layer deposition (PEALD) offers a variety of advantages over other thin film growth techniques, such as conformal coverage of complex surface structures. However, low crystallinity has been a drawback for PEALD aluminum nitride (AlN) thin films, which makes it impossible to use in many applications. In this thesis, a process for reaching a higher quality AlN grown with PEALD was studied. The process included an added plasma step into the PEALD cycle, atomic layer annealing (ALA). The results of this thesis are divided into material characteristics of the improved PEALD ALA AlN and use of PEALD ALA AlN and PEALD AlN thin films in diverse applications. AlN grown with the PEALD ALA process has improved stoichiometry, crystallinity, and c-axis orientation, and contained less carbon and hydrogen impurities. Amount of oxygen impurities has increased. Post deposition annealing at high temperature in vacuum reduced impurities but did not improve the crystallinity further. The substrate also has an impact on the obtained crystal quality of the film and could aid the AlN film to achieve the preferred structure. The ALA AlN was measured to be piezoelectric when deposited on an aluminum substrate. In addition, ALA AlN grows crystalline on vertical sidewalls. The use of PEALD ALA AlN as a transition layer for further metalorganic chemical vapor deposition regrowth was demonstrated successfully. Silicon surface passivation was demonstrated with PEALD AlN. The film provides passivation for the surface and the highest carrier lifetime was obtained with higher deposition temperature and a combination of annealing and firing as a postdeposition heat treatment.

AB - Plasma-enhanced atomic layer deposition (PEALD) offers a variety of advantages over other thin film growth techniques, such as conformal coverage of complex surface structures. However, low crystallinity has been a drawback for PEALD aluminum nitride (AlN) thin films, which makes it impossible to use in many applications. In this thesis, a process for reaching a higher quality AlN grown with PEALD was studied. The process included an added plasma step into the PEALD cycle, atomic layer annealing (ALA). The results of this thesis are divided into material characteristics of the improved PEALD ALA AlN and use of PEALD ALA AlN and PEALD AlN thin films in diverse applications. AlN grown with the PEALD ALA process has improved stoichiometry, crystallinity, and c-axis orientation, and contained less carbon and hydrogen impurities. Amount of oxygen impurities has increased. Post deposition annealing at high temperature in vacuum reduced impurities but did not improve the crystallinity further. The substrate also has an impact on the obtained crystal quality of the film and could aid the AlN film to achieve the preferred structure. The ALA AlN was measured to be piezoelectric when deposited on an aluminum substrate. In addition, ALA AlN grows crystalline on vertical sidewalls. The use of PEALD ALA AlN as a transition layer for further metalorganic chemical vapor deposition regrowth was demonstrated successfully. Silicon surface passivation was demonstrated with PEALD AlN. The film provides passivation for the surface and the highest carrier lifetime was obtained with higher deposition temperature and a combination of annealing and firing as a postdeposition heat treatment.

KW - plasma-enhanced atomic layer deposition

KW - AlN

KW - atomic layer annealing

KW - thin films

KW - plasma-avusteinen atomikerroskasvatus

KW - AlN

KW - atomikerroshehkutus

KW - ohutkalvot

KW - plasma-enhanced atomic layer deposition

KW - AlN

KW - atomic layer annealing

KW - thin films

M3 - Doctoral Thesis

SN - 978-952-64-1619-9

T3 - Aalto University publication series DOCTORAL THESES

PB - Aalto University

ER -

Plasma-enhanced atomic layer deposition of aluminum nitride : characteristics and applications

Abstrakti

Tutkimusalat

Pääsy asiakirjaan

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