Handbook of Sputter Deposition Technology. Fundamentals and Applications for Functional Thin Films, Nano-Materials and MEMS

640 Pages·2016·24.23 MB·English

by  Wasa K.

Handbook of Sputter Deposition Technology
Coauthors
HideakiAdachi
PanasonicCo.Ltd.
Kyoto,Japan
TomonobuHata
KanazawaUniversity
Kanazawa,Japan
TomoakiMatsushima
KyotoUniversity
Kyoto,Japan
TomoyoshiMotohiro
ToyotaCentralR&DLabs.,Inc.
Aichi,Japan
KikuoTominaga
TokushimaUniversity
Tokushima,Japan
Handbook of Sputter
Deposition Technology
Fundamentals and Applications for
Functional Thin Films, Nanomaterials,
and MEMS
Second Edition
Edited by
Kiyotaka Wasa
Isaku Kanno
Hidetoshi Kotera
AMSTERDAM BOSTON HEIDELBERG LONDON NEWYORK
(cid:1) (cid:1) (cid:1) (cid:1)
OXFORD PARIS SANDIEGO SANFRANCISCO SINGAPORE
(cid:1) (cid:1) (cid:1) (cid:1)
SYDNEY TOKYO
(cid:1)
WilliamAndrewisanimprintofElsevier
WilliamAndrewisanimprintofElsevier
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Firstedition1992
Secondedition2012
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Preface
The first edition of Handbook of Sputter Deposition Technology was published in
1992 (Noyes Publications, NJ) in a series Editions of Electronic Materials and
Process Technology, Materials Science and Process Technology Series edited by
Professor R.F. Bunshah (University of California, LA). The first edition described
sputteringmaterialengineeringbasedontheauthor’sresearchatPanasonic,Japan.
More than 15 years have passed since the publication of the first edition.
In the last 15 years, sputter deposition technology has been extended to a much
wider variety of community not only for the electronics industry but also for the
medical and/or biotechnology. At present sputtering is a key technology for present
and future material processing including nanofunctional materials and micro/
nanoelectromechanical system (MEMS/NEMS).
The second edition enriches the scientific and technological descriptions of the
firsteditionwithnewchapterrelated to“Computersimulationofsputteringdeposi-
tion,”“nanomaterials,”and“MEMS”soastobeusefulfornext10years.
The thin film materials described in this book are based on the author’s profes-
sional works on sputtering deposition for over 40 years in Panasonic, Research
Institute of Innovative Technology for the Earth (Japanese government institute
for global environment issues, RITE), Yokohama City University, and Kyoto
University. Wide varieties of functional thin film materials and processing are
describedinaconcreteform.Anexpertonthecomputersimulationonthesputtering
hascontributedtothesecondedition.Theprofessionalexperimentaldatawithvariety
of examples and the theoretical descriptions will be useful for graduate students and
researchers/engineersinuniversityandindustry.
Part I (Chapters 1(cid:1)3) describes “Introduction of Thin Films and Sputtering
Deposition.” Chapter 1 reviews the fundamentals of thin films and nanomaterials.
Unique functional material properties of thin films are shown and then typical thin
film deposition process is reviewed for a better understanding of the sputtering
deposition. Chapter 2 describes fundamentals of sputtering. Chapter 3 describes the
basicdesignandoperationsofthesputteringdepositionsystem.
Part II (Chapters 4(cid:1)6) describes “Theory and Practice for Sputtering
Deposition.”Chapter4describes thecomputersimulationofsputteringandsputter-
ing deposition. Chapter 5 describes the fundamentals and basic sputtering deposi-
tion conditions of functional compound thin films. The reactively sputtering is
described in detail by an expert in this field. Varieties of sputtering conditions for
functional thin films are shown in tables by an expert in this field. Chapter 6
describes sputtering deposition of key functional materials at present and for future
xii Preface
including ZnO thin films, perovskite ferroelectric thin films, carbide, nitride,
sulfidethinfilms,andorganicthinfilms.
Part III (Chapters 7(cid:1)9) describes “Sputtering Deposition of Nanofunctional
Materials and Related MEMS.” Chapter 7 describes nanofunctional materials
including nanometer superlattice. Chapter 8 describes sputtering deposition of
high-performance piezoelectric materials for MEMS. Chapter 9 describes the fun-
damentalsandfabricationofMEMSusingsputteringand/orplasmaprocess.
The fundamental knowledge about sputtering deposition is widely distributed in
the scientific and technical literature. The present handbook includes fundamental
theory using computer modeling and a variety of professional experimental data as
an example. This publication will make a bridge between fundamental theory and
practical application. I believe this text gives hints for innovative new materials,
newdevices,and/ornewsystems.
The second edition has been completed based on the first edition. I am grateful
to the late Professor R.F. Bunshah (University of California, LA) for his valuable
advice for the publication of the first edition. I am also grateful to Professor K.L.
Chopra (Indian Institute of Technology) for his continuous advice on the publica-
tion of the second edition. I owe my thanks to many material scientists including
Professor T.H. Geballe (Stanford University), L.E. Cross, the late R.E. Newnham,
K. Uchino, S. Trolier McKinstry (Penn State University), D.G. Schlom (Cornell
University),C.B.Eom(Wisconsin-MadisonUniversity)fortheirhelpfuldiscussion.
Finally, this book could not be published without the constant help of members
of Kotera Laboratory and secretary, Kimiko Terakawa (Kyoto University), and my
wife,SetsukoWasa.
KiyotakaWasa
Kyoto,Japan
April2012
1
Thin Films and Nanomaterials
Hideaki Adachi and Kiyotaka Wasa
ChapterOutline
1.1 ThinFilmsandNanomaterials 4
1.2 ThinFilmDevicesandMEMS 10
1.2.1 ThinFilmDevices 10
1.2.2 ThinFilmMEMS 12
1.3 ThinFilmDeposition 14
1.3.1 PhysicalVaporDeposition,PVD 14
VacuumDeposition 14
PulsedLaserDeposition 16
MolecularBeamEpitaxy 17
Sputtering 17
MiscellaneousPVDProcesses 22
1.3.2 ChemicalVaporDeposition,CVD 23
ThermallyActivatedCVD 23
Plasma-AssistedCVD 24
1.4 CharacterizationofThinFilms 25
1.5 SputteringasaNanomaterialEngineering 28
References 36
Thin films are fabricated by the deposition of material atoms on a substrate. A thin
film is defined as a low-dimensional material created by condensing, one-by-one,
atomic/molecular/ionic species of matter. The thickness is typically less than sev-
eral micron-meters. The thin films are typically deposited by a thermal evaporation
of source materials in vacuum. Figure 1.1 shows the typical evaporation process
forthedepositionofthinfilms.
Historically, thin films have been used for more than a half century in making
electronic devices, optical coatings, instrument hard coatings, and decorative parts.
In 1960s, thin film transistors (TFT) and/or thin film integrated circuits (ICs) were
extensively studied. These trials were not used in practice due to the drift of the
TFT. After the developments of Si-(MOS) (Metal Oxide Semiconductor) IC in
1970s, thin film materials were used only for passive devices. The real market of
thinfilmscouldnotbedeveloped likeSi-IC. Avarietyofnew materialswas devel-
oped in academic phase such as a diamond-like carbon (DLC), high-T supercon-
c
ductors. The thin film technology is a well-established material processing
technology. However, the thin film technology is still being developed on a daily
HandbookofSputterDepositionTechnology.
©2012ElsevierInc.Allrightsreserved.
4 HandbookofSputterDepositionTechnology
Figure1.1 Typicalthinfilmdeposition
systeminvacuum.
Substrate
Vacuum
Thin films
Evaporated atoms
Heating source materials
basis, since it is a key in the twenty-first century development of new functional
materialssuchasnanometermaterialsand/orman-madesuperlattices.
Thin film materials and devices are also available for minimization of toxic
materials, sincethe quantity used is limitedonly toasurface and/or thin film layer.
Thin film processing also saves energy consumption in production and is consid-
eredtobeanenvironment-benignmaterialtechnology.1
Thin film technology is both an old and a current key material technology.
Thin film materials and deposition processes have been reviewed in several
publications.2(cid:1)19 Among the earlier publications, the Handbook of Thin Film
Technology4 is still notable, even though 40 years have passed since the book was
published and many new and exciting developments have occurred in the interven-
ingyears.
At the beginning of this chapter, the features of the thin films are reviewed
in relation to their applications for thin film devices and/or thin film micro-
electromechanical systems (MEMS). Secondly, fundamentals of thin film fabrica-
tionprocessesareexplainedforabetterunderstandingofthesputteringdeposition.
1.1 Thin Films and Nanomaterials
Thin films are grown by the deposition of material atoms on a substrate. Typical
thin film growth process on a substrate by the deposition material atoms is shown
inFig.1.2.
Thethinfilmgrowthexhibitsthefollowingfeatures:
1. The birth of thin films of all materials starts with a random nucleation process followed
bynucleationandgrowthstages.
2. Thenucleationandgrowthstagesaredependentuponvariousdepositionconditions,such
asgrowthtemperature,growthrate,andsubstratesurfacechemistry.
3. The nucleation stage can be modified by external agencies, such as electron or ion
bombardments.
ThinFilmsandNanomaterials 5
Evaporated atom
Removing atom
Adsorb on substrate
Trapped atoms
Brownian motion
Nucleation and
film growth
Substrate
Figure1.2 Thegrowthmodelsofthethinfilms.
4. Filmmicrostructure,associateddefectstructure,andfilmstressdependonthedeposition
conditionofthenuclearstage.
5. Crystal phase and crystal orientation of the thin films are governed by the deposition
conditions.
The basic properties of thin films, such as film chemical composition, structural
properties, film thickness, are controlled by the deposition conditions. The thin
filmsexhibituniquepropertiesthatcannotbeobservedinbulkmaterials:
1. Unique material properties resulting from the atomic growth process on the growing
substrates.
2. Sizeeffectsincludingquantumsizeeffectscharacterizedbythethickness,crystalorienta-
tion,andmultilayeraspects.
Bulk materials are usually sintered from powder of source materials. The parti-
cle size of the powder is of the order of 1μm in diameter. Thin films are synthe-
sized from ultrafine particles, i.e., atoms or a cluster of atoms. Ultrauniform
compound materials are possibly synthesized from the atomic collisions between
theadatomsonasubstratesurface.
Anotherconsequenceofthethinfilmgrowthprocessisthephenomenonofsolu-
bility relaxation. The atomistic process of growth during codeposition allows
doping and alloying of films. Since thin films are formed from individual atomic,
molecular,orionicspecies,whichhavenosolubilityrestrictionsinthevaporphase,
the solubility conditions between different materials are considerably relaxed. This
allows the preparation of multicomponent materials, such as alloys and compounds
over an extended range of compositions as compared to the corresponding bulk
materials. It is thus possible to have tailor-made materials with desired properties,
which adds a new and exciting dimension to materials technology. An important
example of this technology of tailor-made materials is the formation of hydroge-
natedamorphousSifilmsforuse insolar cells.Hydrogenationhas madeitpossible
to vary the optical band gap of amorphous Si from 1 to about 2eV and to decrease
the density of dangling bond states in the band gap so that doping a (n and p) is
madepossible.20
Thepropertiesofthinfilmsare governed bythe depositionmethod. Thethermal
evaporation is a well-known process. The deposition process using the irradiation
of energetic species is known as sputtering. Bunsen and Grove first observed