Table Of ContentLecture Notes in Physics 916
Yutaka Yoshida
Guido Langouche E ditors
Defects and
Impurities in
Silicon Materials
An Introduction to Atomic-Level
Silicon Engineering
Lecture Notes in Physics
Volume 916
FoundingEditors
W.Beiglböck
J.Ehlers
K.Hepp
H.Weidenmüller
EditorialBoard
M.Bartelmann,Heidelberg,Germany
B.-G.Englert,Singapore,Singapore
P.Hänggi,Augsburg,Germany
M.Hjorth-Jensen,Oslo,Norway
R.A.L.Jones,Sheffield,UK
M.Lewenstein,Castelldefels(Barcelona),Spain
H.vonLöhneysen,Karlsruhe,Germany
J.-M.Raimond,Paris,France
A.Rubio,Donostia-SanSebastian,Spain
S.Theisen,Golm,Germany
D.Vollhardt,Augsburg,Germany
J.Wells,Michigan,USA
G.P.Zank,Huntsville,USA
M.Salmhofer,Heidelberg,Germany
The Lecture Notes in Physics
The series Lecture Notes in Physics (LNP), founded in 1969, reports new devel-
opmentsin physicsresearch and teaching-quicklyand informally,but with a high
qualityand the explicitaim to summarizeand communicatecurrentknowledgein
anaccessibleway.Bookspublishedinthisseriesareconceivedasbridgingmaterial
between advanced graduate textbooks and the forefront of research and to serve
threepurposes:
(cid:129) to be a compact and modern up-to-date source of reference on a well-defined
topic
(cid:129) to serve as an accessible introduction to the field to postgraduate students and
nonspecialistresearchersfromrelatedareas
(cid:129) to be a source of advanced teaching material for specialized seminars, courses
andschools
Bothmonographsandmulti-authorvolumeswillbeconsideredforpublication.
Editedvolumesshould,however,consistofaverylimitednumberofcontributions
only.ProceedingswillnotbeconsideredforLNP.
VolumespublishedinLNParedisseminatedbothinprintandinelectronicfor-
mats,theelectronicarchivebeingavailableatspringerlink.com.Theseriescontent
isindexed,abstractedandreferencedbymanyabstractingandinformationservices,
bibliographicnetworks,subscriptionagencies,librarynetworks,andconsortia.
Proposalsshouldbe sent to a memberof the EditorialBoard, ordirectly to the
managingeditoratSpringer:
ChristianCaron
SpringerHeidelberg
PhysicsEditorialDepartmentI
Tiergartenstrasse17
69121Heidelberg/Germany
[email protected]
Moreinformationaboutthisseriesathttp://www.springer.com/series/5304
Yutaka Yoshida (cid:129) Guido Langouche
Editors
Defects and Impurities
in Silicon Materials
An Introduction to Atomic-Level Silicon
Engineering
123
Editors
YutakaYoshida GuidoLangouche
ShizuokaInstituteofScience Nuclearsolidstatephysics
andTechnology KatholiekeUniversiteitLeuven
Fukuroi,Japan (KULeuven)
Leuven,Belgium
ISSN0075-8450 ISSN1616-6361 (electronic)
LectureNotesinPhysics
ISBN978-4-431-55799-9 ISBN978-4-431-55800-2 (eBook)
DOI10.1007/978-4-431-55800-2
LibraryofCongressControlNumber:2016930107
SpringerTokyoHeidelbergNewYorkDordrechtLondon
©SpringerJapan2015
Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpartof
thematerialisconcerned,specificallytherightsoftranslation,reprinting,reuseofillustrations,recitation,
broadcasting,reproductiononmicrofilmsorinanyotherphysicalway,andtransmissionorinformation
storageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilarmethodology
nowknownorhereafterdeveloped.
Theuseofgeneraldescriptivenames,registerednames,trademarks,servicemarks,etc.inthispublication
doesnotimply,evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfromtherelevant
protectivelawsandregulationsandthereforefreeforgeneraluse.
Thepublisher,theauthorsandtheeditorsaresafetoassumethattheadviceandinformationinthisbook
arebelievedtobetrueandaccurateatthedateofpublication.Neitherthepublishernortheauthorsor
theeditorsgiveawarranty,expressorimplied,withrespecttothematerialcontainedhereinorforany
errorsoromissionsthatmayhavebeenmade.
Printedonacid-freepaper
SpringerJapanKKispartofSpringerScience+BusinessMedia(www.springer.com)
Thisbookisdedicatedto thememoryof
Prof.GeorgeRozgonyi.
Preface
This book provides the basic physics behind crystal growth, modeling, and eval-
uation techniques used in silicon materials science and especially emphasizes the
importanceofthefascinatingatomisticinsightsintodefectsandimpuritiesaswell
astheirdynamicbehaviorinsiliconmaterials.Duringthelast20yearstheseinsights
have become directly accessible by newly developedexperimentalmethods, first-
principles calculations, modeling, and other computational techniques. Central to
the success of semiconductor technology is the ability to control the electrical
properties of silicon material. The role of intentionally added dopants to produce
theoptimumconcentrationofholesandelectronsforagivenelectronicapplication
iswellestablished.However,thepresenceofunintentionalimpuritiesandstructural
defectsinthelatticecanhaveadramaticeffectontheelectronicpropertiesofsilicon
andarethereforeatopicofattentionthroughoutthisbook.
Accordingly,thebookaddressesyoungresearchers,scientists,andengineersin
therelatedindustry.Themainpurposeistooffertoreaders:(1)anin-depthcoverage
ofthebasicphysicsofdefectsinsiliconmaterials,(2)anintroductiontoatomistic
modelingaswellascharacterizationtechniquesrelatedtodefectsandimpuritiesin
silicon materials, and (3) an overviewof the wide range of research topics in this
field.
In Chap. 1, Hartmut Bracht discusses diffusion of self- and dopant atoms in
silicon. The diffusion studies comprise experiments on self- and dopant diffusion
performed (both) separately and simultaneously. The mathematical treatment of
diffusion–reactionmechanismsis introducedin orderto explainwhat information
regardingatomicmechanismsandpropertiesofpointdefectscanbededucedfrom
diffusionexperimentsperformedundervariousexperimentalconditions.Computer
simulationsofatomictransportinsiliconarecomparedwithexperimentalself-and
dopantprofiles,andthemechanismsthatdeterminethediffusionofself-anddopant
atoms in silicon are summarized. Finally, yet unsolved questions concerning the
propertiesofpointdefectsinsiliconandthediffusionbehaviorinthree-dimensional
confinedsiliconstructuresareaddressed.
vii
viii Preface
In Chap. 2, José Coutinho providesthe groundsfor defect modeling in silicon
materials using density functional methods. His chapter starts with a review of
the theoretical framework and tools, including the relevant methods to treat the
exchange-correlation interactions. It then describes how to step up from total
energies,electrondensities,andKohn–Shamstatestotheactualdefectcalculations.
Particular emphasis is given to the calculation of spectroscopic observables such
aselectricallevels, localvibrationalmodes,spin densities, migrationbarriers,and
defect response to uniaxial stress. The defect survey starts with a description of
elemental intrinsic centers. Understanding their fundamental properties will be
crucial to unravel the features of many substitutional and interstitial impurities
involvingdopants,transitionmetals,carbon,oxygen,orhydrogen.Inthelastsection
thelatestdevelopmentsinmodelingdefectsinsiliconnanostructuresarediscussed.
Whileholdinggreatpromisesregardingthefascinatingopticalemission/absorption
properties,nano-siliconpresentsmanychallenges,particularlywithregardtodefect
control,doping,andelectricaltransport.
Chapter3 isdevotedto reviewingtechniquesthatcharacterizeandquantifythe
propertiesofdefectsandimpuritiesinsiliconmaterialsanddevicesintermsoftheir
effect on free carriers and their recombination and generation behavior. Anthony
R. Peaker and Vladimir P. Markevich explore, in particular, the application of
deep-leveltransientspectroscopyand its manyvariantsto electronic gradesilicon
during critical process steps. The effect of ion implantation damage and process
contaminationisconsideredinrelationtospecificdevicesforsignalprocessingand
powercontrol.Inthecaseofsolargradesilicon,problemsassociatedwithdifferent
types of silicon material are considered including the use of inexpensive impure
siliconfeedstock.Thecomplexitiesof theinteractionofunwantedimpuritieswith
extendeddefectsincastmulti-crystallinesiliconandtheproblemsinevaluatingthe
defectsconcernedisdiscussed.Thephysicsofcarrierrecombinationatthesedefects
ispresentedandrelatedtomethodstomapminoritycarrierlifetimeincastsilicon.
The status and limitations of the techniques for qualification of material for solar
cellsisdiscussed.
InChap.4,JanVanhellemont,KozoNakamura,EijiKamiyama,andKojiSueoka
are concerned with single-crystal growth of Si and Ge. The so-called Voronkov
criterion defines a critical value (cid:2) of the ratio (cid:2) Dv/G of the pulling rate v
crit
over the thermal gradient G at the melt–solid interface of a growing crystal. For
(cid:2) >(cid:2) , the crystal is vacancy-rich and can contain large vacancy clusters that
crit
are detrimentalforgate-oxideperformanceand forthin-filmepitaxialgrowth.For
(cid:2) <(cid:2) , the crystal is self-interstitial-rich and in the worst case will contain
crit
dislocation clusters. For (cid:2) (cid:2) , the crystal is free of grown-in intrinsic point
crit
defectclustersandoptimalfordeviceprocessing.Theimportantimpactofthermal
stress (cid:3) at the melt–solid interface and crystal doping on (cid:2) is clarified. As
th crit
(cid:3) increases with increasing crystal diameter, controlling G and v become a real
th
challengeforthedevelopmentoffuture450-mmdiameter,defect-freeSicrystals.
Chapter 5, written by Bing Gao and Koichi Kakimoto, discusses large-scale
numerical modeling for silicon single-crystal growth for large-scale integrated
systems and solar cells, where the goal is to reduce the number of light elements
Preface ix
anddislocationsfromthecrystals.Foranaccuratepredictionofcarbonandoxygen
impurities in crystalline silicon material for solar cells, a global simulation of
coupled oxygen and carbon transport in a unidirectional solidification furnace is
implemented. Both the gas flow and the silicon melt flow are considered in this
chapter. The effects of flow rate and pressure on the impurities are examined. To
effectively control dislocations in crystalline silicon, the relationship between the
locationsofactivateddislocationsandthecoolingfluxdirectionis studiednumer-
ically from the perspective of activation of slip systems. A model of dislocation
propagationina crystalduringcrystalgrowthandcoolingprocessesisdeveloped.
The first part describes how to calculate stress and strain in the crystal. Then,
the mechanism of dislocation propagation is explained by using the Alexander–
Haasen–Sumino model. This part explains a non-linear system of dislocation
propagation, which is important to predict the dislocation density quantitatively.
Finally,preferentialslipsystemsordislocationpropagationarediscussed.
In Chap. 6, Gudrun Kissinger reports on nucleation and growth of oxygen
precipitatesfromthepointofviewofclassicalnucleationtheoryandonpossibilities
andlimitsoftheirdetection.Theinitialstatesofoxygenprecipitationassuggested
by ab initio calculation are described. Results on the impact of intrinsic point
defects, doping, and co-doping are presented. A second focus of this chapter is
directedtowardstheimpactofgrown-inoxygenprecipitatenucleiinsiliconwafers
onoxygenprecipitation,andcreationofhigh-qualitydefectdenudedzonesduring
device processing. Conventional and modern methods of thermal processing and
theirimpactonoxygenprecipitationarediscussed.Methodstodeterminethegetter
efficiencyofoxygenprecipitatesandtheirresultsaredescribed.
In Chap. 7, Takashi Sekiguchi and Jun Chen describe electron-beam-induced
current(EBIC)andcathode-luminescence(CL) techniques,whichhavebeenused
for the electrical/optical characterization of extended defects in Si. For both
techniques, they use scanning electron microscopes (SEM) for electron beam
irradiation. The electric current induced at the internal circuit and light emission
areused forimagingofEBIC andCL, respectively.Theyclassifythe dislocations
and grain boundaries (GBs): clean dislocations are not per se electrically active,
butdobecomeactiveaftermetallicdecoration.Large-angle(LA)GBsalsobehave
like dislocations. The coherency of GB and the degree of contamination are the
majorfactorsthatdeterminetheelectricalactivitiesofLA-GBs.Small-angle(SA)
GBs have certain carrier recombination activities at room temperature. Owing to
dislocation bundles, SA-GBs emit D-lines and can be distinguished in the D-line
imaging in the CL mode. The SA-GBs are classified by these D-lines according
tothecharacterandmisorientationangle.EBIC/CLshavebeenextensivelyusedto
characterizemulti-crystallineSiforphotovoltaicapplications.
Chapter 8 by Guido Langouche and Yutaka Yoshida explains that the
hyperfine interaction between an atomic nucleus and its surrounding charge
and electromagnetic-field distribution is extremely sensitive to the atomic and
electronic configuration of this atom. In the field of defects and impurities in
semiconductors, the study of their hyperfine interaction can therefore contribute
substantially to their identification and characterization. The introduction of
