Cvd Introduction

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Introduction to Chemical Vapor Deposition

A) Chemical Vapor Deposition

CVD TypesCVD Uses

CVD Process

General CVD Reactor Concept

General CVD Process Advantages

General CVD Process Applications

B) Dealing ith !ngineering "cience o# CVD Reactions

Transport Processes

$aminar %lo Boundary $ayer Concept

&ther "usceptor to %lo A'is &ptions

Thermodynamics

Reaction (inetics

C) &perational &vervie

Polycrystaline "ilicon

"ilicon Dio'ide

itride %ilms



LPCVD APCVD

PECVD

Chemical Vapor Deposition

Current &ptions

Atmospheric Pressure CVD

Plasma !nhanced CVD

$o Pressure CVD



CVD

"ilicon itride

"ilicon dio'ide Polycrystalline"ilicon

!pita'ial $ayersCustomi*ed "ur#aces

Insulator Conductors

Barriers


CVD Applications



Arrival Flow

Rate

"u+strate

Input Flow Rate

r , Groth Rate o# %ilmg

rg

"ur#ace Reaction Rate

G r o t h R a t e

% i l m


CVD Process

"ur#ace Reaction



CVD Reactor Concept

Reaction Chamber

SusceptorControlled Thermal Environment

Controlled Pressure Environment

Film Surface

Hydrogen Carrier Gas

With additional film significant containing gas components



General CVD Process Advantages

Excellent Step CoverageLarge hro!ghp!t "#$$ A%min film gro&th'Lo& emperat!re Processing "()$ to #$$$ C'

Applica*le to any Vapori+ation So!rce echnology"Laser CVD for direct Writing'

General CVD Process Applications

Epitaxial ,ilmsEnhance performance of Discreet and -ntegrated .ipolar Devices

Allo& ,a*rication of /A01s and C02S in .!l3 S!*strate

Dielectrics-ns!lation *et&een Cond!cting LayersDiff!sion and -on -mplant 0as3sCapping Dopant ,ilmsExtracting -mp!ritiesPassivation to Protect Str!ct!res from

-mp!rities0oist!reScratches

Polysilicon Cond!ctorsGate ElectrodesCond!ctors for 0!ltilevel 0etali+ations

Contacts for Shallo& 4!nction Devices



.' Dealing &ith Engineering Science of CVD /eactions

ransport Processes

hermodynamics

/eaction 5inetics

ransport Processes

!r*!lent ,lo& 6o7 to 0any Particles8

0olec!lar ,lo& 6o7 to Lo& a hro!ghp!t

Laminar ,lo& " 2nly 2ne Left7 0a3e Do'

Set Conditions ,or Laminar ,lo& " Lo& /eynolds 6!m*er Val!e'



R = D V !

/eynolds 6!m*er

Linear Velocity

!*e Diameter

9 "

Gas Density

Gas Viscosity



Laminar ,lo& Conditions

Diameter and velocity in tens of cm and cm%s &ill give

/eynolds n!m*ers in laminar flo& regime

R = #$%& ' #()

*rowth D +R! #+ T !

#$&%

T+ , ! -! P!.oundar, /a,er

Thic0ness

Rea1ent Partial Pressure

Rea1ent2s *as Phase Coe33icient

o3 Thermal Di33usion

($44



S!sceptor

Input Reactant *as Flow

.o!ndary layer develops along s!sceptor flo& axis

X1

X2

X3

X4

*raphic E'a11erated 3or Visual E33ect

Velocity Gradient Profiles at Discrete Points along ,lo& Axis

1 2 3X

4X X X

: n d e r d e

v e l o p e d

f l o & p a t t

e r n a t t h i s

p o s i t i o n a l o n g

s ! s c e p t o r

D i s t a n c e A * o v e S ! s c e p t o r



rends in GradientsVelocity Val!es

-ncrease Along S!sceptor-ncrease A*ove S!sceptor

emperat!re Val!es-ncrease Along S!sceptorDecrease A*ove S!sceptor

/eactant Concentration Val!e

Decrease Along S!sceptor-ncrease A*ove S!sceptor

Velocity Gradient Profiles at Discrete Points along ,lo& Axis

1 2 3X

4X X X

: n d e r d e v e l o p e d

f l o & p a t t

e r n a t t h i s

p o s i t i o n a l o n g

s ! s c e p t o r



2ther S!sceptor to ,lo& Axis 2ptions

Design ,actors -ncl!de ,lo& Direction and Wafer Angle

A' -np!t gas flo&

.' -np!t gas flo&

C' -np!t gas flo&

D' -np!t gas flo&

E' -np!t gas flo&



hermodynamics

CVD Phase Diagram

Give range of inp!t conditions for CVD that co!ld prod!ce specificcondensed phases8

Presented as ,!nction of emperat!re or Press!re vs 0ole ,raction

.

.oron codeposit only in High

.oron 0ole ,ractions in inp!t

stream

.oron codeposition favored at

higher press!res81200

oC

1000o

C

1400

o

C

/eactant Gas 0ole ,raction

.%"i ; .'

$8$# Atm #8$ Atm

$8<

i. = Phase

H%HCl > $8?)

Use Graphic for Educational Value Only 7 th

Conference on CVD 1979

K.E. Spear

Electrochemical Society Vol 79

i.

=@

.Phase



.Cl %CH ( > (

Use Graphic for Educational Value Only

J. Electrochem. Soc. 123 ,136, 1976

Bernard Ducarror

#$ B(

#$ B

#$ B=

#$ B#

#$ B$

#$ B(

#$ B

#$ B=

#$ B#

Partial Pressure 3or 5ethane

.6C 7 C

.6C

.6C 7 .

.

CarbonVapor

#&(( ( C

#$( Atm

.oronBCar*on CVD Phase Diagrams



1 0 0 0 o C

9 0 0 o C

1 1 0 0 o C

I n p u t e a c t a n t ! a " # o l e F r a c t i o n

S i % " S i ; V '

$ 8 <H % H C l > $ 8 ? )

U s e G r a p h i c f o r E d u c a t i o n a l V a l u e O n l y

7 t h C o n f e r e n c e o n C V D 1 9 7 9

K . E . S p e a r

E l e c t r o c h e m i c a l S o c i e t y V o l 7 9

1 2 0 0 o C

VCl8

VCl8 7 V)Si4

V)Si4

P > $8=) atm

Vanadi!mBSiliconBHydrogenBChloride CVD Phase Diagrams



Vanadi!mBSiliconBHydrogenBChloride CVD Phase DiagramCom po" ition ratio" for input $a"e" of VCl 4 %SiC l4 % &2 are not e'uili(rium )alue"

ransport Processes vs hermo dynamics

*a"+, # a+ e a V- S i3 film.

roc e/ ure , F rom C V h a"e ia$ ra m fo r a 9 00 oC / epo"ition an input $a" mo le

fraction of 0.20 can (e u "e/.

ro( lem , " V- S i3 form " on "urface actual rea$ent $a" S i mo le fraction co n"um e/

at "urface i" hi$her 0.37- than the input reactant $a" ratio "upplie/

0.20. *hu" Si at "urface i" /ep lete/ more Vana/ium i" a)a ila( le at the

"urface a n/ ac tual e'u ili(rium "hift" to pro/uc tion of V 3Si.

roce/ure, &ol/ temperature con"tant (ut "hif t the input $a" mole fract ion to 0.-.

ro( lem , " V- S i3 form " on "urface actual rea$ent )ana/ ium $a" m ole fraction

con"um e/ 0.52- i" hi$her than the input $a" mo le fraction for )ana/ ium .

*hu" Vana/ium at "urface i" /eplete/ more Silicon i" a)aila(le at the

"urface a n/ actual e'uili(rium "h ift" to pro/uction of VSi 2.



/eaction 5inetics


12!, 79" #1979$

Be%mann ,J. Electrochem. Soc.

#+T ' #( + 9!

-.0 5.0 7.0 6.0 9.0

1.0

10.0

Titanium Diboron Deposition Arrhenius Plot

P = ($8&4 Atm$

Input 3low Rate = 6&8 cc +min

.+. 7 Ti! = ($&&

Cl+Cl 7 :! = ($44

Input *ases

TiCl6

.Cl4

:8

Reaction Temperatures 8((( 9 to #((( 9!

;#




Arrhenius Rate Pro3iles

#+T

1.0

10.0

af

/ower Sur3ace Temperatures:i1her Sur3ace Reaction Rates




Partial Pressure Reactant *as

1.0

10.0

Arrhenius Isotherms

a

fSur3ace Reaction /imitin1 *rowth Rate



# + T

.est Fit 5odel .ehavior based

<perational /ine 3or Deposition at :i1her Pressure

r1#

<n ) Calibration Runs

#+ T 8

r18

Desired *rowthRate

ew <peratin1Temperature

#+ T#

Current

<peratin1 Temperature

Current

*rowth Rate

ln (r g2

/ r g1

) (q act

/k ) (T 2 T

1 / T

2 T

1)





Silicon dioxide

Lo& emperat!reLoose adhering deposits on side &alls of reactor8 " Particles that cancontaminate the film8

At high silane press!res allo&s for gas phase reactions8 " Promotesparticle contamination and ha+y films'

,air step coverage

Lo& film density " =8 $ g%cm '

Deposition rate complex f!nction of 2xygen concentration

Easy chemical reaction8 " Lo& activation energy7 $8( ev "#$ 3cal%mole' '

,ilm depends on gas phase transport of material to s!rface

Lo& temperat!re allo&s prod!ction of films that &ill serve as

ins!lation *et&een al!min!m levels in device8

Si

:

::

:

Si72

<'idation$

6(( ; 6)( C72

Films Contain :,dro1en as

Silanol Si<:!:,dride Si:!

<r @ater

Amorphous Structure o3 Si<6 Tetrahedra



Si

:

:: :

Si 2

<

&)( to %)( C

Si

<

C

C

:

:

:

:< <

C

:

:

C

:

:

C&2C&3

C&2C&3

Silane Tetraetho',silane

TE<S

Si 2

&)( to %)( C/PCVD!

4( PA to 8)( PA

#(( to #((( std$ cc + min

0edi!m emperat!re



S i

C l

:C l :

S i 7 2

= 8 < $

A ) ( t o ? ( ( C

D i c h l o r o s i l a n e

/PCVD

itrous <'ide

High emperat!re

6onlinear press!re dependence that is f!nction of &afer position8

Small amo!nts of Chlorine in films that tends to ca!se crac3ing in a poly layer'

/eagent depletion pro*lems

Phosphor!s doping is diffic!lt8 " he phosphor!s oxides are volatile at highdeposition temperat!res8'

Excellent :niformity



Except for epi and parallel plate processes both sides of wafer are coated.

Equipment

Furnace with or without vacuum capability Plasma hamber

CVD is Cr!cial to ,a*rication of -Cs7 Especially 02S,ES

!"he #ottom $ine%

Pad &ilicon 'ioxide

First (onolayer of &ilicon )itride

&i

l

l

)

* *

Precursor

NH Si Cl

* l

*

l

l l

*

*

)

* * *

&i

l

l *

* &i

l

l *

*

Documents

Cvd Introduction