M SCAT Eil]N G C-1A (⊃r⊥1tZ2LA∴rZON OF
S 1ZJ S= (m UCrm R T =CT∃∃S
( _)
By
propertiesofsmallsemiconductorIrticlesofSiandGewitha
semiconductor.ThereareTnain tvo SeSOfthisthesisWork:
mdes innonpolarsemiconductors.Theother istocontributeto
s trOSCOPy in combinationwith electronmicroscopy.The I
sIetra from thegas-evaprated SifrticlesWith free tDundAry
conditions are measured for the first time. The structural
changes of the Siand Ge particles in thin films are detected
zmdamlyZedbythe m SCatteringmeasurementssueeessftnly.
glowJischarge-deposited Sifilms.Somecomentsaregiven on
thetheoreticalstudiesdealingwith the finite-sip:eeffects,
measuredforthefirsttime.Theresultshowsthat concepts
am rrhous-likes Ctradonotmeanthecontinuousrzmdomnetwork
showing thesimilaritiesbtween Simd Ge.Possiblemechanisms
microcrystallinemodel instead of the continuous random network
e.
thesispssible.
world of this research field,ofEob University for his con-
stm tgui ICe,encouragementand suggestionsduringeveryphase
The author t40uld like to express his sincere thanks to
professorS.lyaShiofKotc Universityforhisvalblediscus-
fortheir suggestionsand guidanceduringthepreparation of
tdlOSenamesarefound inhispaperslistedinthereferences,of
Professor Yaw oto's latx)ratory for their help and useful dis-
cussions in this thesis work. In frticular ,the author td es
pleasureinacknowledging the initialpartplayedbyMessrs.T.
TYle author wishes to thank Professor Y. kawa ofOsaka
thiversityforthepreparation ofglow-dischargedeposited Si
Shimonishi.fortheirhelpandencouragement.
2.6 Summary
Particles
5.4 nSpectraofGem iumParticleswithFreeBot ry

Particles
tween stars,tells us valuable information on the birth and
groIJth of stars. Thus a great interest in the small particles
spreadsoverengineersand scientistsfrom a surprising variety
of disciplines; electrical engineering,solid-sate physics,
chemistry,astronomy,meteorology,zmdbiophysics.
Inordertotreatthesmallparticlesinawidefield,itis
derstwd the various prope rties of the small ticles results
fromtheirsmallersizethan ausualsi21eOfbulkmatter.
propertiesbgin tochangedrastically.Thusit isdesired to
for the research on the smallparticles.Now a new field in
solid state physics grotJS aiming to study the physical
properties of solids smaller than l FLm in sip:e,Which are
called byvarioustermssuchassmallparticles,ultrafineIr-
result in the brilliantcolorsofstained glasseslthe optical
properties of smallparticleshave ben the subject of intense
investigations froththe latenineteenth century.1)A wide
variety ofopticalspectra of small‡rticles can explained
in tens of special electromagnetic oscillation in the par-
ticles,called electromagnetic surface modes or surface
plaritons.2) TYle COnCept OfthesurfacepIaritons isextended
to other particles such as semiconductor ones,and hasbeen
successful in explaining experimental results. For example, Ibyashi3) hassummariZ:ed thetheoriesofthe surfacenodesin
thesmallparticlesandhasshowedhowthesurfacemdescanhe
zmdnSCtraOfGapIrticles.
electromagnetic surfacemodesisvalid only forpolarphonon
mier∝leviees.Thereforthevibrationaland opticalproperties
2
years
modynamiealand structuralaspectsasasolid in thevitreous
statesorthequantun statisticalstudiesasa random network
system.Nowmuchattention isdevoted to amorphousmaterials, mainlyamorphoussemiconductors,from viewpintofsolid state
devices.
valency controllability in glow-discharge-produced amorphous
siliconby Spear and LeComber in 1975.4) Since then,a con-
siderableamountof intensive investigationshasbeencarried
fortshaveproduced variouspracticaldevicesutilizing amor-
tors,andintegratedphotosensors.
Fortheamorphoussiliconaswellastheotheramorphous
materials,thechemicalbrdingstructureisoneofthemostim-
figurationshaveben investigatedbythevibrationalproperties
ional modes measured in Raman and infrared spectra have
revealedthelocalbondingenvironmentand the role ofincor-
papers.Howevera few analyses in fomativedataobtainedby, mainly,high-resolution transmission electronmieroscopyhave
supported the microcrystallinemodel.89) Therefor further
studiesaredesiredtoconfinnthestructuralmi elsbyusi a
both thefinite-sizeeffectsonphysicalpropertiesof small
particlesand thestructureofamorphous solidsareizTIPrtant
for not only a basic research but also an applied field.
However,upto this time,nooneconsidered in cormeetionWith
thesmallsemiconductor-frticlestudyand theamorphoussemi-
thestudiesoverlappingtheabove two fields are possibleby
considering smallparticlesormicrocrystals for nonplarsemi-
isfidtoinquireintotheappearameoffinite-sip:eeffectsof
tionalproperties.areexamined experimentallyby,mainly,using
thefrticle-si2;e analysisofgas-evaprated small siliconpar-
ducedbythermalamealingor laser irradiation are examined to
clarifythestructureoftheSifrticles.12-15)
Changes in the Raman spectra of evaporated1416) and glow-
dischargedep⊃sited l?) thin Sifilms arediscussed in terms of
thepeak frequencyar° linewidthofaTO-likemodeandavolume
fractionofcrystallinity.TheeffectsofthermlIm ealing for
theevaporated filmsandofthedepositioncondition forthe
structuralinfom tionoftheSifilJnS.
Inchapter4,acomprativesttdyofSiparticlesand films
isgivenbyusing themeasurementoftheRamandepolarization
plari2:ation properties of the Si films are not interpreted by
the continues random network mdeltut favor the microerysta1-
1inemcxlelinstead.
In chapter 5, the investigation dealing with the sTTnll Si
particles isextended tosmallgemanium particles.1920)The
sane analyticalproceduresasused fortheSiparticlesareap-
films.Theresultsobtained inthischapteragreewith those
LightbySmallParticles (Wiley-Interscience,New York, 1983).
Interscience,NewYork,1982).
(1975)1193.
(1986)19.
Soe.Jpn.54 (1985)1173.
Speetroseopy,1984)p.234.
p.UltrasonicElectronics,Tokyo,1983,Jpn.J.Appl.
Phys.23(1984)Supp1.23-1,p.72.
7
2134.
YanOtO:J.Phys.Soe.Jpn.56 (1987)243.
scatteringeI10)measurement;theresultshavebensuccessfully
phononsandsurfaceplasmonshasbeenreportedforthesmall
controversy.nthesttxliesoftheseTTnterials,RaIInSCattering
film19-21)and the changes in the Raman Spectra due to the
variation ofcrystIlite size have ben reprted.22-24)However
allexperimentsonmicrocrystalshavebeencarriedoutinthe
a systematic exTriment on the m SCattering from the small
silicon particlespreparedbygas-evaprationteclmique.2627)
Si particles in cornection vith an electron diffraction sttRiy.
We find that the Si particles possess the same crystalline
structureasthebulk Siin spiteoftheiramorphous-likeRaJTW
tegrated intensitydecreaseswith an increaseoftheparticle
ingorlaser irradiation isalsomeasured toclarifythestruc-
theoreticalstLdiesrelatedtothepresentexprimentaregiven,
suggesting a lack of proper theory to account for the results
fully.
gas-evaporation technique,3233)in which bulk materialsare
evaprated inan inertgasatalowpressurenthepresentex-
nitride boat in an argon gas.A schematic diagram of the
10
l
ArCos
BorTlb
distancetXtWeen thetDrOn nitridetx)atand the substrate.The
gas pressure tJaS Varied from Olto 1Torr for the samples of
the sip:e depndence experimentland was kept at O17 Torr for
the samples of the thermal amealing End the laser irradiation
exp riments.
variousmaterials:glasscoveredwithevapratedthinahmi num
film,quartz,sapphire,singleCrystalsilicon,and tungsten.
ThedifferencesintheRaman spectrameasuredWerehardlyob-
siliconused in thethennalannealing (seethe laterdiscussion
in §25).mugtheresultsreIrted inthischapterweremostly
thealuminumfilmforas-depsitedmeasurement auseofacom-
treatment,wereusedforthethemtalarnealingaJd thelaserir-
radiationexpe riments.
The thermal annealing was carried out in a quartz tube
evacuateddo topressureof the order of 10-6 Torr.The tub
containingtheszmpleswasinserted inan eleetricovenThean-
nealingtemperaturewaskeptataconstantvalueWithin2%ina
range of 100 to 800oC.The armealing time was fixed at 30
minutes for allresultsrep rted here.The s les amealed at
thedesiredtemperaturewerequenchedtoroomtempe ratureinthe
p werusedforthesizedependenceandthethermalamealing ex-
perimentswaslessthan 50mWtopreventa localheatingofthe
samples irradiated at a laser pwerbelow 50mW. In laser ir-
radiationexpriment,leaving amarginweused arx)werof 30mW
Subsequently,thepowderslmPlescollectedonamicrogrid
coated with a carbon thin film were studied by a JEM-200CX
(JEOL)electronmicroscope operated at 200kV.According tothe
usual TnZm er,10I34) themicrographsobtainedwereusedtodeter-
electrondiffractionftternSWerealsomeasured.
analyzed by aDuPont 310CurveResolver.The spectracould
resolved intoseveralcoTTP nentSinarange of250to600cm-I,
reveal speCtralchanges,andhasbeen successfullyapplied to
ter3.
varies froTn70 to 220AWith increasing the argongaspressure
from 0.1to 1Torr.It isnoted thatt,hevaluesobserved are
13
linesiliconfi.22'23)
Todeducethegrowthkinetidsofthesiliconparticles,We
forthesTlpleprefredatthepressureof0.5Torr isshown in
], (2.1)
where dx and 6 are the individual particle size and the
geometric standard deviation.This log-normal curve is also
plotted inFig.2.2;thecurvecalculated fromtheexperimental
hastofallWithinatd givenby J=1.48± 0.2forcrystal-
line inertgas-evaporated particles;although silicon is ex-
cldedfromtheconsideration.3435) thesaneistruefortheSi
frticlesinvestigatedhere (6=1.39).
vaprsource losetheirenergyrapidlybycollisionwiththegas
homogeneousnucleation,ar° those embryonicparticlesthengrow
firstobservationofthelog-normaldistributionforthesizeof
Sirrticles.
14
preIredatthepressureof0.5Torr.Thestaplesdenotethe
bl1-sha°ctm erepresentsafittoalog-no¶ldistribu-
tionfunctioncharacterizedbythefollowingvalues:a=103 C A and q= 1.39, ere aand 6 are the statisticalmedian
and thegeometric standarddeviation.Theareaunderthe
(theright)correspnding to,resp∋ctively,thesmallestfmd the
ringsareclearlyobservableeven forthesnPleswith a=70A,
and thebrightsptSareOften found forthesamplespreparedat
that the Si rnrticles have the ordinary diamond structure; the
latticeparameterscalculated from (111),(220)and (311)planes
are 5.41,5.40 and 5.43 A respectively,and agree with the
standardvalue of silicon (5.43A)Within an experimentalac-
CuraCy
Siparticlespssessthesame irnerstructureas thebulkcrys-
temedthesiliconmicrocrystalsreasornbly.
With crystallineand amorphous-likephases (d=220A).This
si2:edependenceisshoTm inFig24.It issome tsiTnilarto
theeaeOfmicrocrystallineSifilms2223)thatthecrystalline
inFig.2.4islargecompredWith thatofthefi containing
''amorphous-1ike'spectrum oftheSifrticlesdifferssubstw -
are sho in Fig. 2.5.The resolved cotnpnents are classified
into four modestnsed on the center frequency in the range of
250 to 600cm-1.The relative integrated intensity I (theper-
centage area ofthe indivi1compnent to the total area)of
eachmi eisplottedasafunctionofdinFig.2.6.Inthefol-
designatedbythesubscriptofthecenterfrequency
17
D )
∝
600
Fig 24 Size dependence of the -Zm spectra of the
siliconparticlesThevalues indicatedbydirected lines
D
withd=70 ard 220A.
h V ∝
Fig.2.6 Dependeneeoftherelativeintegrated inten-
perimentalpints. In our resolvingprocedure,the errors
of Iand thecenterfrequencyareestimated tobeatDut5%
independently of .Because of these tendencies and their
frequencies,weassignthesemdestoLA- (7300) 1d (Zdβ0)
20
assigned to the allowed-TO-phonon mode of crystalline
silicon,36) whichmeansthe earisingfromtheallowed I125
shouldtk notedthattheallowed-TOmdesoftheswpleshaving
than theotherlowermodefmdappe arsinthesampleoflargea.
aresufficiently largetoregardthemassinglecrystalsfor
crystallineparticlesand theshifttolow frequencyofthis
withthefrequencyof430cm-I hasadifferentcharacter,i.e.a
ulike sigrlalofamorIus siliconwas frequentlymuchweaker
than thoseoftheothermodes.40) Consequently.weassign this
mi etoanewsurfacemode;thistern comesfrom itscharacter
we refer to soTPe theoretical sttdies to accountfor the nan
spectraofamorphouszmd/Ormicrocrystallinesilicon.232441-
vectorselection-rule232443)ornormalmodecalculation.4142)
observationoftheshiftandthebroadeningofthe nallowed
freetDldarycondition,nonofthestudiesgiveusan overall
amorphous-likespectraoftheparticleswiththecrystalline
structureandthespectralstructureinvolvingthesurfacemde.
Theattempttointerprettheamorphous-likeRamanspectrahas
experimentalandtheoretical SttxliestJill requiredtoaccount
lnordertocheckthestructureofthesiliconparticle,it
is useful to examine Whether the In Spectra Of the silicon
frticlesareaffectedbythethe¶larnealing28-30)zmd laser
bytheamealing isslightoverthewholetemperaturerange.We
sP CtrainFig.2.7byusingthesameprocedureasapplied in §
in theregionbetween the surfaceand Tt>1ikemCdesasabroad
comp nent (450cm-1),togetherWith theothermdesdiscussed
in §2.4.Thedependenceoftherelative integrated intensities
ontheamealingtemfCrature.30)Thatis,thismderesultsfrom
0-Si angle,Which has been the subject of theoretical andex-
perimentalinvestigationsonvitreoussilica.46-49) uswecon-
D )
N V ≡ V ∝
400 500 RAMANSHT(cm-
temperature.
24
V∝9_L N
ANNEALINGTEMPERATURE (oC)
Fig.2.8 Dependenceoftherelativeintegratedintensities
discussedinChapter5.
mW)zmd ata low-pwer level (30mW)aftercooling.An example
oftWon Spectraforthehigh-andlow-fWerlevelsisshown
to the lower-frequency side and becamebroad;this frequency
shiftand thebroadening apprently indicatea rise in tempera-
tureduring laser irradiation.Toquantitatively estimatethe
forbulk Si.This asstmption is reasonabletm ause of the dis-
cussion stated in this chapter that the Sifrticles are crys-
talline.
resultreportedbyBalkanski eta1.50) Their calculation in-
cluded contributionsfrom four-phononarharnonicprocessesand
has provided a good fit to the experimental values for the
frequency shift and the linewidth up to 1400. It is,there-
fore,appropriatetocompreour results.
Figure2.10showsacomparisonbtween thetheoreticalline
forbulk Si and the measured pints for the Sifrticles as a
relationshiptxtweenthepeak frequencyshiftand thelinewidth
perature Tbythe expressions50)
(2.3)
perimental pints;thatallfinite-sizeeffectsareincltRled in
frequencyshiftandthe linewidthariseonly from thetempera-
p intsandthetheoreticallineisfairlygod inspiteofour
600
s le at two laser-Pwer levels (30zmd 300mW). The two
spectra arenormalized tothemaximum intensity.Vertical
solid line was derived from the theoretical calculation
reprted byBalkanski eta1.50) The circles designate the
experimentalpints.
29
ticleswith freetx)undary condition,wemeasured for the first
time the n Spectra from the smallSiparticlespreplred by
gasevaprationtechnique.Theelectronmicroscopicstudyshoved
clearlyobservedandanalyzedbyresolving the spectra intoa
spectrum even though their structure iscrystalline.Wecom
mentedsometheoreticalstudiesto interpretthisobservation;
ticlesastheCrystallineone.
30
References
3) R.FbchsandX.L.miewer:J.Opt.Soc.Am .58(1968)319.
4) R.Eri andR.RIPPin:J.Phys.C:SolidStatePhys.1
(1982)75.
T.Okada,T.Iwaki,K.Yamamoto,H.XasaharaandK.Abe:
Spectroscopy,1984)p.234.
tures2(1986)581.
3.1 Intrduction
RaJnan SpeCtrOSCOpyisnon-destructivezmdisoneofthemost
generally accepted that the Raman spectrum of a- or FLe-Si
evolvesfromabroad spectrum around 480cm-1 characteristicof
an amorphous film to a single-line spectrum around 520 cm-1
characteristic ofbulk siliconcrystal (e-Si),dending on the
crystallinityofthe film.Thisfeaturehasbeen reported for
tion.1112) n these experiments,the above change in Raman
sPetrumhasbeenutili2:edasafastconvenientmethod ofdeter-
minir Whetherthefilmiscrystallineoramorphous.
showtheamrphous-likeRm spectrumeventhoththeparticles
arecrystalline.On thebasisofthisobservation,weextendour
ent allows us to determine quantitatively the structural
properties, especially the change in erystallinity,of so-
Cal1ed a-Si film prepared by the classicalevapration JTNeth∝1.
Evaporated Sifilmsareusedbecause oftheir simple nature,
35
prducedbytheGDtechnique,e.a.theeffectsofthe incorpra-
search intothesefilmsisthusexrectedtogiveamoredetailed
shotJinthischapterthatthestructuralchangeofthermally-
ing.Moreover,the energy ofactivation of the crystalli21ation
will deduced fromthevolumefractionofcrystallinitydeter-
film,aswellasthe linevidthof theRaman spectrum and the
crystAllite sizecalculated from X-ray diffraction.The results
presented inthischaptershowthatthevolumefractionofcrys-
JLC-SifilJn.In additionweconsiderthe finite-size effectson
perimenton thermallyamealed Sifilm reprted in thischapter
andthecalculationTTd ebyRichtereta1.16)
3.2 Experimental
preIred byvacuum evapration;e-Sichipswere evap rated from
aron-nitrideboatinavacuumoftheorderof 10-6 Torr.All
thefilmsweresufficientlythick (10 m),thesubstratesdid
Weresplitintosmallchipsatnut 1cm2 inarea,zmdthesechips
The sampleswere placed in a quartz tube evacuated to a
pressureoftheorderof 10-6 Torr,then inserted inanelectric
oven.Thearnealingtemperature T3 0feachrultJaSmaintained at
here. The samples annealed at the desired temperature were
quenchedtoroomtempe ratureinvacuum .
oscillator of 4 MHz and DC electric field applied perpen-
dicularlyto theRF electric field was employed forthederx)si-
tion of SiH4¶-e RF rDWer,tJaS Varied from 40 to 300W and IX:
bias voltagell,aSCOntrOlled from - 50 to+100V,tJhere the ∝
biasvoltagetJasmeasuredtJithrespecttothesubstrate.TYleto-
talgas floIJrate Waskeptat 70cc/minwith agaspressure of
0.9 Torr. The substrate of tty CryStalline Si Was used and
iLs temperature rs was kept at 250, 300 and 35()oC. Using the
abve IrameterS,We get the JJC-Si fibs with abut 1 JLm in O
thickandthedePSitionrateofr).24-6.17A/Sec
usingtheScherrerfomllla.
si_ljcon films tJereTneaSured in aconvenient 90oscattering con- r;
figuration tJithabut50mW of 4880A argon-ion laserradiation
focused by a (ylindrical lensat room temperature.TheRaan
37
standard (Tool(d photomultiplierand otoncounting system.The
RarnanspectraWereanalyzedbyaDu Pont 310 Curve Resolver;
†hisapproach is thesameasusd forthesmallSiparticles in
Chapter2.
Theresultsobtained byRim scatteringTneaSurement Of a-
fmd e-Si have ben interpreted in tem lS Of chaqes in the
T0-2-4781718)and TA-1ike1819)phonon frequencies,the
linevidth of the TO-like phonon band,379-121718)and the
volumefractionofcrystallinity.5620)Theseparametershave
b nds.10)Inthissection,wewilldiscussthestructumlchange
of the evaporated 8-Si film in terms of the frequency and
linevidthofthem-likephononmdeand thevolume fraction of
thatcorresprdingtotheTOtwdine-Si.
films annealed at various temperatures.The spectrum ofas-
deposited film is a broad asyTnmetric hump arotlnd 480 cm-I
characteristic ofso-Called a-Si,While,for the films annealed
at theannealing temperature T 700oC,a sharp structure
slightlybelow 520 cm-1dominates thespectra.These results
clearlydemonstrate thegrowthofthecrystallites induced by
600
filmsarnealedatvarioustenp rattueB.
"
200
a U
linewidthsaredetemined intwoways. (Seedetails in the
text.)
InFig.3.2,theapfrentpeak frequencyar° thelinevidths
of the TO-like mode are plotted as a function of Ta. The
linetJidthsweredetemined in twoways;onewastheusual full
the intensity at 600 cm-I (closed circles),ard the other was
obtainedbydoubling thevaluemeasured from thepeak to the
halfmaximum Onthehigh-frequencyside (opencircles).Thelat-
pendenceofthe two linewidths on Ta showsavery similar ten-
dency,soitis_difficulttodiscussthecontributionoftheLL>
likeTTKXleinthistJay.
justatx)ve700oC.Thisindicatesthatthelargegrowthofcrys-
taIlitestakesplacevigorouslyatx)vethistempenture.However,
crystalli2:ation, tm use its value depends strongly on the an-
nealir COnditionsand isalSo affected byacotnplex effect of
theTO-and LO-like modes.In fact,in sples subjected to
preheattreatmentatabout600oC for 30minutes,theabrupt
fromaconsiderablylowertemperature.
ourknowledge,thereare twometh∝k ofdetemi ning yF fromthe
measured nSpeetra6720) apartfroTnanalysisofpolari2:ed
Raman scattering,which is suitable forquasi-singlecrystal
silicon22) but not for the present case.Mishima et81.56)
Simply used the ratio of thepeak heightat 520cm~l to the
heightat480cm-1, dIileTsu eta1.20) used the integrated in-
tensitiesoftheresolved escorrespndi tOthecrystalline
andamorphous-likeparts.In thepresentdiscussion,Weadopta
methd similar to the latter,b∋cause it seems that the fh
peakheightsusedintheforrdonotcorrectlyreflectthena-
frequencyrange.SinceZcand Zaaremeasuredonthesa SCale,
eveninarbitryun its,weCan definevl as
whereqristheratiooftheintegratedlmanCrossSectionfor
cause thevaluesof Zcand Z∂ obtainedare freefrom thecon-
tributionfromtheI0-likemodeandaeeidentalmodesarising
fromimpwitiessuchasoxygenintr cedduringthedeposition.
600
tallineTnrt(a)and amorphous-likepart.Thevalues indi-
valueof rhasbeen reported tobe from about0.1for a-Si
filmsrelative.torx)1ycrystallineorsingle-crystalSi 2324) to
0.88for 8-SifilJnSrelativeto JLe-Si.20 Obviously,thevalue
of drvaries with various parameters such as the exciting
photon energy and the crystallite size. However, we have used
hereaconsbntvalueof0.8as Tsu etal.havedone.20) This is
reasonablebeausetheopticalpropertiesofthecrystallinezmd
amrphous-likephases'aresimilarinacoexistentfilm.
mationofstructurearecorrmonlydescribedby theAvmi for-
tivation energy Ea ata fixed temperature Ta,which isexactly
thepresentcase,theAvramifom aIncomes
constzmtunderthepresentconditions.
tively,non-eat-treated films (the same as those in Fig 31)
and filmspre-heat-treatedatatDut600oCfor30minutestefore
the regular amealir. In spite of the different value of vfO
(vfO =O or 0.16),the structuralchange of two sample sets
obysthesameequation,eq.(3.3).
44
and after annealing.Thecirclesand crossesdesignate
range.Thevalueof E isthe slopedetermined by a least-
squaresfitto.theexfrimentalpoints.tispintedout for
400oCataconstNtrate.Inddition,wepstulatethattheEa
of0.35eVisidenticaltotheactivationenergyfortheviscous
flowofSi,0.37eV(8.63kcal/mol).28)
fullyexplainthepresentresult.Ourinterpretationwillbe
frticleszmdfilms.
linevidth (fullWidthathalfmaximum)ofW lpeakr,andthe
resolved mdes isshown inFig. 3.5,inwhich theprefration
conditionsaregiven.Ourinpurpseistodiscusstheeffect
ofpreparationconditionsonthecrystallinityofthefilms.
46
^
N V ∑ V
tegrated intensities of the crystalline zmd amorrhous-like
compnents.Thevaluesindicatedbydirected linesarepe
shown in Fig.36.As thefWer increases,the increase of the
crystallinity is observed. In frticular,vl has a linear cor-
relation With thepwer. In contrast to vF,d and r indicate
more complicated bhavior:ahas the imum around 180 W zmd
thendecreasesgradually;simultaneously,r decreases firstand
thepwerklowandabove 180Wareprotnblycaused by,resrec-
formed inthefilm aswellasthefinite-size effectsdiscussed
It is instructive to compre the atx)ve resultswith those
reported by Mishima et a1.,5) because they have clearly
descritxd the effect of RF pwer on the crystallite fomd in
GDJep sited JLe-Si.Theyhaveconcludethatthevolumefraction
thisincreasearisesfromtheincreaseofthenunbrofcrystal-
1ites tJithout any acc nyi Chare in the crystallite size.
mefomerconclusionagreeswithoursinspiteofthedifferent
method ofdetermination of vF; the latter,however,disagrees
with ours.We feel that the constant value of d is a over-
simplified assumption.The resultreported here indicatesthe
variationofawiththerx)wer. Moreover,thefi depsitedat
IJeCOnCludewith theaid of vF thatthedense filmswith the
crystallitesaredepsit.edathighpwer.
48
^ 1
a u Jn lO
O
200
linewidthof npeak r,and tecrystallitesi2:e aasa
ftmctionoftheRFpWer
49
Fig 37 The volume fraction of erystallinity y′,the
linewid of pe ak I.,aTXlthecrystAllitesi2e dasa
functionofthe biasvoltqe.
figureareasfollows:(1)VFS inthefilmsdepositedatthe
=350Chavethemaxinum lueamund 50Vandaredegradedby
thepsitive Vbhigherthan 50V.(2)Thefilmsderx)Sitedat Ts
dm eviththecha∫lgein Vbfrom-50to100V,butrsofthe
V.
interpretation:In theconditionofnegative Vb,thegrowing
radicals.Thereforetheincreaseinrofthefilmdepositedat
thisStress.On theotherhand,thepsitivebiaspromotesthe
decreaseof d at Vhigherthan 50Vdisagrees;thisisat-
tributable.atleastinpart.tothedifferentmethd applying
seems thatSiHxradicalsarerelated tothisdifference.Since
thehigher Ts enhancesthesurfacemobilityofdiffusingradi-
hydrogen evolution takesplace atabove 300.C,3637)itmay
hirderfromgrowingthecrystallite.Thesecontraryeffectsmake
neededforfullclarificationoftheformtionkinetics.
several theoretical calculations is made on the first order
Ramanmodeobserved in silicon films.The formation of large
mieroerystals in Sifilmsgivesrise tothe sharpcrystalline
mode,whichmoreorlessaccompanies the frequency Shift and
broadening.Severalattemptstoestimate the finite-sip;eef-
refX3rted intermsofacontinuous bm-networkstructure,10)a
thin slab,38)and a relaxation of the wave-vector selection
rule.7'16J39)
mostsuitAble forcαringour resultsbecM e Of their simple
htvaltble results. n their model,the localization due to
the relaxation of the Conservation of crystal momentu in
microerystalhas b endescrib dbyaneww efun ction ¢ in the
fom
r2
where qoisthephononwavevector,L is thediameterOfthe
lattice.The qtm tity ¢ isno longer the eigenfunction of qo, soitleak toabroadeningoftheRm -active lineard acon-
52
results of the evaporated and the GD-deposited Si films are
plottedbyopen1dclosedcirclesres tively.
0 1
filmamealedthe¶1ly.
between the shift of peak position and the linewidth for
evarx3mted film zm ealed thermally is explained fairly well by
the simplemdel.However,thisisnotthecase intherelation
high frequency side ofthecalculated line.This isprobably
caused by the effect of stress. me shift to higher frequency
slgeStS a COmPreSSive stress.40) In adLhtion,we can estimate
the stress to severalktn r, which is the same order of the
other estimation.33'41) The above resultshowsthatthe relaxa-
tionofthetaVe-VectorSelection rule iseffective forthe in-
terpretationoffinite-si2:eeffectofthemicrocrystalsinfin.
But itmust noted that the finite-si2:e effects ofthe small
particlesWith freetn ryconditionarenotexplained bythe
amrphous-like broad srnctrum of small Siparticles With crys-
talline structurediscussed in §2.4isnot interpreted bythis
mdel.Although some mechanismsareprop)ed,4243) furtherex-
pe rimentalard theoreticalinvestigationsarerequird.
3.5 Sum ry
Wereamlyzed intermsofthepeak frequency and the linevidths
for theTt)-likemdetogetherwith thevolume fractionofcrys-
resolved modesCorresponding to the Crystallinepartand the
arPhous-like one.Moreover,by fitting v′ to theAvrani for-
mula,we found the tt40 different activation energy for the
structuralcharlie.Theverylowactivationenergyof0.35eVwas
54
flowofSi.
ar° the ∝ bias voltage on the structural properties was dis-
cussedbyusing v/,thelinewidthofthe ISpectrum,andthe
interpret the finite-size effect of smallparticle formed in
film,wec red our exprimentalresultsofevaprated andGD-
depsited filmswiththetheoreticalcalculationmadebyRichter
selection rule.We suggested that furtherstudy isneeded to
clarifythefinite-si2:eeffectsforthes11particles.
SolidStateCom .40(1981)161.
2916.
56
16)
17)
18)
19)
20)
21)
22)
23)
24)
27)
28)
29)
30)
(1983)783.
Alloy (PergamonPress, bn,1965).
M.Jami,D.D.Alred,D.C. th anda.0.Seraohin:Sol.
242.
ford:Appl.Phys.ktt.30(1977)561.
37) S.(uz,R.W.Collins,M.A.paeslerandW.bul:J.Non-
tures2(1986)581.
58
orientedsi1ecrystal.On theotherhard,thesytZmetryCharac-
smallparticles and fluid systems are characteri2:ed by a
dep lari2:ationratio A definedastheratioofthede‡Iari2:ed
totheplarizedunintensities.Inanycasethepolari2:ation
measurementOfsmllsiliconfrticlesl)followingour previous
andtoContributetothestudyofthestructureofamorphous
time.Thentheresultsarediscussedbyamlogywithliquidsarid
§2.2.Byvaryingtheargongaspressurefrom 0.1to1Torr,we O
sized.Thesize veredetermined fromelectronmicrograS
used in §2.2 To amlyze theIIarization properties, we re-
corded lh nspectrawithtwodifferent m Plarizationcon-
figurationsusir theright-anglescatteringgeometry.Thatis,
resTnCtively, dlereX axisisthen forthedirectionoflaser
deplari2:ationratio p asZγ/ZB.Themeasured valuesofA were
Calibrated against reference peaks of Carbon tetraehloride,
vhose 218- and 314-cm-1 lines are knotm to be completely
deplarized (A=0.75).
4.3 Discussionof nDef1ariationRatio
TbefX)larized (ZB)ard dep larized (Zy) n S tra for
therrticles350ard 60Ainsi2;eare Shotm inFig.41For O
particles smaller than about 100 A, the polarized and
deplarized spectrashowabroadzm or10uS-likebmd.Forlarge
ofthesmallsiliconIticles350and 60Aintheaverage
ticleSaSa functionoftheaverageparticlesi2:e d.There
are three Asdetemi ned from the whole spectrum (a solid
line),the crystalline node (a broken line),and the
BunOrPotB-1ikemi e (ashJotted line).
the polari2:ed and depolari2:ed_intensities over the Whole
spectralrange studied and then took theratio.Furthermore,
sincethespectraconsistofseveralmi es,wealsoobtained the
62
ing procedureused forum -polarized spectra (see §2.2).Then
theratioswere.Calculated from the integrated intensitiesof
tworesolved modes,the amorphous-likemode ( 480cm-1) and
thecrystallinemde ( 520cm-1).
Theobtainedvaluesof psareshotm inFig.4.2asa fum I
tionof d.The p of whol e s trumdecreases from 0.45at d= O o
60A to 0.25at a=350A . The psofamorphous-likeand crys-
tallinemodes are slightly largerand smaller than the p of
olespectrum,respectively,inthesizeraJieOfFig.4.2.¶le
largersip;eisdominatedbythecrystallinemi e,an errorin A
of crystalline mde is small for larger si2:e. Thus we discuss
the implication of As by sepamting the region into two,the ()
regionsofsizesmallerwdlargerthan atDut100A.
mainly the region of larger size.As reprted previously,128)
thegas-evapratedSiparticlespossess thecrystalline struc-
ture.We thus regard the present system as an assebly of the
frticleswith the same n tenSOrSaS those of the bulk Si
By analogy with liquids and gases,3) p for the randomly
orientedparticlesisgivenby
isotropICandanisotropICrnrtSOfthetensorJrespectively.
thediagonalcompnentsofthe an tenSOrSforthephonon of
astheF28 SyTTmetryfmd A-selectionrulearethoughttob in-
operative. If it is so, should increase to the ideal
deplarizationlimitof0.75asthefrticlesi2:eincreases.To
may be considered that the higher value than the ideal
depolarization limitforaplanepolarized incident light
amltiple scattering;thenatural light leads β → 6/7.3) To
elucidatethesi2:eeffectsoffIari2:ationprope rty,furtherex- C
difficulty in making stably the Sifrticles much larger size;
thisdifficulty isprotxiblycausedbyadecomp sitionofatx)ron
mde.For this region,A rangesarotRld 0.5, ich agreesWith
valuesofaJnOrPhousormicrocrystalline Si filmsprepared by
variousmethods.4-7) Incomparing our resultwiththoseofSi
turesandthep⊃larizationproperties.KobliskaandSolin9)sug
te used to test the validity of two structuralmdelsof amor-
phousTTnterials,arardomnetworkmodelard amolecularone.On
theprope rtiesof p asfollows:In acontinuousrandom network
((N)mi el,A shouldte frequency-dependentbeeauseallvibra-
inashowsa featureless frequency-independentvalueofabout
0.4,asplotted inFig.4.3.Fi e4.3alsoinclulestheresult
have a typlealamorphous structure.Thesevaluesofthepar- t
ticles and fi are the same within an exprimental error.As
65
Inaddition,themolecular-likeClustermodeldonot explain
films. We thus suggest that neither the CRNmodel nor the
molecular-1ikemi elexplains the structures ofmaterials show-
ingamorIous-1ike nSpectra.
0 1- ∝
N O tlV Z l∝ V 1 0 d
400 450 500 RAMANSFT (cm~')
Fig.4.3 Frequencydependenceofthederx31ari2:ationratio
psofthesmallsiliconparticles60A intheaverage -
films consist ofmicrocrystals.The agreement between the
results of particles and those of films indicates that the
structures in both Systems must essentially be identical at
least in Raman scattering process.We thus believe that the
microcrystallinemdelisappropriatetodescrib thestructures
crystallinefrticles exhibit theamorphous-like spectra is un -
certain atpresent. yashiandYazTW tOll) reported an attempt
to interprettheamorphous-like signalasan enhanced signal
from the surface layer ofnicrocrystals.Theoretical investiga-
tionsproperlytreating intrinsicsurfaceeffectsarerequired.
ratio p ofsmall siliconparticleswithan averageparticle O
size from 60 to 350A.The low values of p for the particles
having acrystallinepeakwerenotexplained by regardingthe
particlesas thebulkSi.Thusbulkconceptssuch asthe F2g
syTtm try Zmd k-selection rule were inoperative to tile SJTRllSi
frticles.Bycompri PSOfthe SiparticlesWith those of
Si films,we have showed that thebroad amrphous-like spectra
do not mean the continuous random network structure or
molecular-likecluster.Theexp riJTkmtal results presented here
werenotpredicted byexistingtheories.Todiscuss the finite-
(Wiley-Interscience,hndon,1970).
405.
(1982)377.
havesimilarproperties.Forexllple, n SrXeCtraOfso-Called
resblesasharppeak observed inbulkcrystals (locatedat520
cm~l for Si and 300 cm-1 for Ge),and a broad one called
amorphous-likecoTTP nent,Which resemblesabroad peak observed
in so-called amrphous films (located at 480 cm -1 for Si
and 280 cm-1 for a-Ge). So it is informative to exp d our
investigation on thesmallparticlesofSito thoseofGe by
usi thesamemethd .
ThesiZ:edependenceof nSpectrafromsmllGerrticles
a1.1) nleydemonstrated that the m SetrunOfthe Ge Ir- C
ticlesassmallas80A showstebroadarrhous-likefeature;
attention,in thischapter,on the structuralchanges of small
Ge particlesboth tJith freeboundary conditions and in thin
film.Byusingthesameanalyticalmethod asused fortheSi
69
highenergyreultsfromthecoalescenceofmicrocrystalS.3)
singlecrystal (purity9N)OntocrystallineSiwafersatroom
250to600oC for20or30minutes.
wafersby evap ratingbulkGe fromatuStenbatinArgasof
0.75Torr (gas-evaporation).The Geparticlescollected Were
the film for20min.Theannealing temperature Ta wasvaried
from200to500oCwithastep50oC. RaJTm SCatteri from theas-dep sitedad arnealed samples
of particles and films was measured by a SPEX RAMAIJOG 5M
spectrophotometer equlPPed with a doublemonochromator and a
C photon coun ting system. The 4880- or 5145-A line of an Ar-ion
laserwasusedtoexcitethespectra;toavoidthelocalheating
one ( 280cm-1). Theresolvingwascarriedoutonamicrocom-
puter (FbjitsuFM-8)byassumingGaussian lineshapeS.
AftercompletingtheRamanmeasurements,theGeparticles
70
were scrapd off from the substrate and dispersed in ethyl al-
coholA drop of the alcohol was put on a standard electron
microscoplC grid covered with a thin carbon film.After the
evarx)rationofalcohol,thegridwasexamined_byaHitaChiHS-7D
electronmicroscope .
The typICal n Spectra Of evapmted Ge films amealed
thermally are sho in Fig.5.1.In the middle part of this
fi e,two Spectra resolved into the crystalline nde ( 300
cm-1)ard theamorphous-likeone ( 280cm-1)arealsoplotted.
The volume fraction of crystal1inity v/ can determined from
theintegrated intensitiesofthecrystallineand any)rbhous-like
thestructuralchanges.The Arrheniusplotsoflnl(1- vFO)/(1-
vl) are sho in Fig. 5.2. t is evident that the structuml
change of evaporated Ge films is veil described by the same
mechanism observed in the Sifilms (§3.3).Fbrthemore,froma
leastsquares fit to the experimental points,the activation
energyEa isfound tob O13eV fortheincipientStageregard-
lessofthearnealing time , Idto thevalueatDVe 1.0eV for
the later stage dependently on the amealing time . It is noted
thattheenergyofthe incIPlentChange agreeswith the activa-
tion energy for the viscous flow of Ge,0.14 eV (2.74
kcal/mol),4) and that this result of the Ge film is consistent
tJiththatofevarnratedSifilm (see §3.3).
D )

N V ∑ V ∝
middlepartcontainstworesolvedspectraofthecrystalline
600500 400 300250
Fig.5.2 Arrheniusplotsoflnl(1-V/o)/(1-′)versus
minutes.Thesolidlinesareleast-squaresfitstotheex-
perimentalpints.
73
stage isthelowestenergyinthecrystalli2:ationenergiesofGe
from 0.18 to 3.2eV.5-10) One reason yve observethe lowest
value isthat them SCattering isvery sensitive to varia-
tions in structural orderofsO-called amorphousstate.In fact
thesttdyusi theRam linewidthonamealedamorphousGe and
Sifilmshasdetermined avalue for thestructuralrelaxation
closestvaluestothepresentresult intheliterature.And the
higherthanthosevalues.
can seethattheas-depsitedsampleshowsabroad nbmdat
noted that the appearance of the amorphous-like compnent does
not always imply the random network structure of materials
studied;gas-evaprated Sild Ge particles smaller than atnut O
100Ausually show thisamorphous-likecomponent,eventholh
they are crystalline.ll12) 0LlrmeasurementOftheaveragefr-
ticle size from the electron micrographs shows that the as- C
depsitedsamplecontaincrystallineparticlesassmallas90A.
74
TnZniumfrticlesontheamealingtemperature Ta.Am exaple1
of the decompsition of the s trum into the crystalline
and amorphous-likemdesisshown forthespectrum Ta=400
C.
75
tainedbyanalyzingtheRam spectraofthesmallgermanium
isobserved,eventhhasmallpeak atroun d 300cm-1 appears
at Ta= 450oC. Themostdrasticchaqe in the s trumoccurs
en Ta israised to500oC;thecrystallinepeak atarotmd 300
cm-1 grolJSabruptly and the amorphous-likecomponentbecomes
veryweak.Wenote here that the s etralchangespresented in
Fig.5.3 for the Ge particles resemble very much those pre-
viouslyreprted for thermally armealed Si (§3.3)and Ge (§
5.3)filJTB.
fraction ofcrystallinity vF.then plotted lnl(1- vFO)/(1-
vE)] asafunctionof 1/kBTa (Arrheniusplot).This issho in
Fig.5.4indicating theclose similaritybetween thesfCtral
changesseen fortheGeparticleswith freeb yand theSi
and Ge particles in thin films.We can see that the plot is
foldedatthe temperaturewhere the strong crystallineRaman
peak abruptly emerges.For the present Ge frticles,we obtain
the lowactivationenergyE. =0.10eV,which isslightly lower
thanthatforthe film (0.13eV).Wealsoobtainthehighac-
tivationenergyEa =2.5eV,which is slightlyhigherthan that
for the Ge film (1.4 eV). It should b stressed thatalthough
thevaluesofthe activation energy obtained are slightly dif-
ferent from those for the Ge film,the Arrheniusplot obtained
isverysimilartothatfortheGefilm.
after thethermalannealing.Form the electIOn micrographs
measured,weobserved thatwhen Ta 450 oC thernrticle size
reTnainsalmostsame,Whileat Ta =500 oCtherrticlesi.ae in-
77
directly from the electron micrograbhs by measuring the linear
dimension ofpartieles along only one direction of the
mierographsTheaveragedeteminedbythisprocedureimplies
tainedare a=89A fortheasJepsited sampleand a=95, 96 0
and 200A forthesnplesamealedat Ta=400,450and 500C, respectively.Note thatthe particlesbecome about two times
largerthan beforewhenamealedat500C. The above experimental results indicate that an abrupt
growthoftheGefrticleso∝)urstetween Ta =450and 500oC, at a temperature much lover than the melting pint of bulk Ge
(934C);theabntgrowth oftheparticles leadstoan abnt
increase in the intensityofthecrystallineRamansignalard
theGep rticleswithfreeh) y (§5.4),theGefin(§5.3)l
andtheSifilm (§3.3).Sowediscussherepossible Jtm hzmisms
servationsbyhighresolutionelectronmicroscopy ( )have
1inemdel:(1)Saito12)showed atnut 14-A sutnicroerystallites
Ounnazd eta1.13)reported 15-30-Asutmicrocrystallitesin a-Si
illips eta1.14) Supprted the microerystalline model on the
basis of the observation of Bragg diffraction from super-
nanometer regions of so-called amorphous Si,ich reveals the
existenceofcrystallineclusterstoosmallto observedbyX
served by M for gas-evaprated frticles of Si and Ge,10)
ard arrhous films otherthan SizmdGe suchasSiO,16J W)317)
and SiGe.18) It isnoted that these resultsobtained through
HRlareconsistentwit our conclusionpresented inthisthesis
At first,we discuss the incIPlent StageWith the low ac- t
tivation energy based on the microcrystalline model. Our
resultsindicate that thecrystallite si2:eremainsalmostthe
blieve that the process involves the rearrangement of surface
atoms.We pstulate that the film iscomISed ofmicroerystals
havingslightlyJeviatedordistorted atomsatsurface layers.
Thus the microcrystals Can restricted easily by ordering of
thesurfaceatomsfromlowteTTpe ratureataCOnStantrateOflow
intx)ndangledeviation.
Theab⊃ve asstption is supp rted by indirect evidence ex-
tensively. (1) Extemled X-ray-absorption fine-structtue (EXAFS)
measurementson arPhous Ge showed the increase ofthe second-
neightx)rpeak strengthwith an atb entOfthe localorder,819-
21) The second peak was considered to be a measure of the
tetrahedralangledistribution.Therefore,sincetheinelplent
reasonablethattheenergyrequisitetothevariation inkmding
thatchangesinthendanglewidthof7%,ich isapracti-
particlegrowthcanbewellexplainedbythelow temperature
thesmokeparticlescollidewitheachotherand thenuniteWith
faceenergy.bito26) stdiedindetailthegrowth ttNeChanismsof
meltingpintoftmlkAg (962oC)Inour ameali eXriments, thegrovJthofSiandGe particlestakesplaceon thesubstrate,
not in theconvection stream ofgas.Howeverthecoalescence
growthispssible,becausetheparticlesaresodenselycol-
lectedorfCkedthattheytouchoneanother.
the lattice vibration.If tJe adopt the Lindeman'smelting
fornula29) forsimplicity,theratioofthemelting t rature
of a small particle T to that of a bulk crystal 'Tb Can be
expressedas Tp/Tb=(a p/eA)2,where apad eAaretheDebye
teTnperatureSOftheparticleand ofthebulkcrystal,respec-
agreesverywellwithhisexperimentalliquid-likecoalescence
measurements,31) he could Show thatthesurface Itingcoales-
cenceoccursbytheconnectionof (100)planes.
ForthepresentGeparticles,wecarnotpreciselydetemi ne
thesurfacemeltingcoalescence,takesplace.However,a fact
thatthefrticlesobservedbyelectronmicrographsappe artobe
muse the liquid-like coalescence may result in spherical par-
ticles as pinted by Rait0.26) After our experinental results,
81
wecan approxitelyset Tp =748K (475oC), thet ratureat
tJlich the coalescence takesplace.Then,insertir Tb=1209
and 0b =378K fortNlk Gel) into the ve relation,we can
obtain a rough estimateoftheDebye temperature ofsmallGe
frticles as 0p =295E.To our knowledge,neither the X-ray
data nor theLEEDdata,Which allow ustoestimate theDebye
temperatureofGe frticles,are available.It is ofgreat in-
terest to perfom X-ray wd LEED ePeriments on Ge ard tocom-
fretheresultsWiththe veestimteofap.
amorphous Si and Ge films. As mentioned in before,the depen-
denceofmn SpectrumOntheamealingtemperatureand theAr-
rheniusplotobtained fortheGeparticlesWithfreetD ryis
very similar to that obtained for a-Si and a-Ge films.This
close similarity allows us to assume that nearly the same
phenomenaoccur inbththegas-evapratedmicrocrystalsId so-
section,the recent HREM observation indicates that the 90-
called amorphous films are Composed of extremely small
microcrystals.At leastqualitatively,thesemieroerystals in
the films are expected to bhave like the frticles With free
btmdary.From the present results,we can attribute the crys-
tallization process with high activation energy to the coales-
cencegrowthofthemicrocrystals.
=1.4eV).¶lisquantitativedifferencemayarise from thedif-
aryconditionattheparticlesurface.In fact,ourasJepsited C
snple contains the crystallite of the order of 90 A in size,
82
whilethose in a-Ge filTTIS arerep⊃rted to oftheorderof 14 0
A.13) In addition,theGefrticleshave free surfacesand con-
taminations around the particles such as oxygen atoms may
prevent the coalescence,dlile microerystals in aQ films are
closelyfCked and thebonding betweenadjacentmicrocrystals
more easily. Furthemore,the frtial b ndiI txtWeen adjacent
microcrystals may facilitate the Coalescence.Thus the
microcrystAls in so-called arPhous Ge fiS Can grow With an
activationenergy loverthan thatfortheGeparticlesWith free
The structural changes were observed for the Ge particles
tx)th with free std ing 1d those closely rncked in thin film.
¶lat is,two-step changeswere detected in the Arrhenius plots
obtained by resolvir the n spectra ofthe splesamealed
thermally,indicatingthesimilaritiesbtweenSiandGe.
QlthetnsisofthemicrocrystallinemCdel,thesestructural
gested that the incIPlent Stage With the lotJaCtivation energy
arises from the ordering of the surface atoms,and that the
abruptfrticlegrowth ofthe latter stagewith high activation
energyisattributedtothecoalescenceoftheparticles.
83
References
(1982)75.
Yamamoto:J.Phys.Soc.Jpn.56 (1987)243.
Nostrd Reid10ld,NewYork,1978)p.1021.
FilS47(1877)203.
mtn.54 (1985)447.
12) S.Hayashi:SolidStatecm . 56 (1985)375.
1415.
T.btsutra:J.Phys.Soe.Jpn.40(1976)603.
38(1977)157.
I.M.Morbito,Jr.,.F.SteigerandG.A.Somrjai:ys.
Rev.179(1969)638.
85
s trOSCOPyincombinationwithelectronmicroscopy.Therehave
Forourpurpose, n SCatteringhasbenarx)werfultoolbe-
film.mestructuralchangesinducedby,lnainly,thermalamea1-
thisdeviationhastofallwithinabmd givenby 6=1.48
arrhous-likebroadspectrum(d=70A)tD amixedsrxeCtrum C
withcrystallinearldarrhous-likephases (a=220A).It C
wasnotedthatthesiliconparticlesassmallas100Ashow
( 430cm-1
thethermIamealingandlaserirradiationexperimentswere
made.FortheisochronalarmealingoftheSifrticles,the
sma11changewasobservedandattribtedtotheformtionof
irradiationwaswellarnlyzedbyusingthetheoreticalca1-
aJTk)rIous-likecomponents.vl wasthenappliedtotheAvrami
thatthetwo-stepstnK:ttualchangewithactivationenergies
of0.35and0.87eV,andthatthelowenergyof0.35eVis
identicaltotheactivationenergyfortheviscousflowof
Si,0.37eV(8.63kcal/mol).
discharge(GD)-depsitedSifi .Thedepedenceofprefra-
structuralpropertieswasdiscussed by using vl,the
linewidth oftheRaJrLZm Setrull,and thecrystallitesize
vithan averageparticlesizefrom60to350Awasreported
forthefirsttime.ThelowvaluesofA fortheparticles
theparticlesasthebulkSi.Thusbulkconceptssuchasthe
particleswith thoseoffilms,weshowed thatthebroad
in thin film were studied by using the same analytical
meth∝lasused for theSiparticles.Wefoundthatthetvo-
resolving the n SrCCtra Of the swplesamealed ther-
mally,indicati the similarities txtveen Siand Ge. The
activationenergiesobtainedwere0.10and2.5eVfortheGe
Itwasnoted thattheenergyoftheincipientc geagrees
consistentwiththatoftheevapmtedSifilm.
Ge film and the Si filJTl,Were discussed based on the
microcrystallinemodelinsteadofthecontinuousra∫domnet-
energyresultsfrom therearrarLgementOfsurfaceatoms,and
1,1951.Hegraduated from Tsuyam NationalCollegeofTeclm01-
Company,Ltd,in April of that year,and spent four years
developing and nufacturir p wer transistors and ICs. He b-
came a facultymekrofTsuyaJTn NationalCollege ofTeclmology
in April of 1975,and studied as a research worker at Xobe
University from Hay of 1983ti11February ofthenext year.H
iscurrently aLecturer in the Department ofElectronics and
ComputerEngineering,Tsuyam NationalCollegeofTeclmology.
SocietyofAppliedPhysics,theInstituteofElectronics,Infor