ALD and CVD Ni using Ni Amidinate Precursor

Huazhi Li1, Deo V. Shenai1, Zhefeng Li2 and Roy G. Gordon2

1. Rohm and Haas Electronic Materials LLC, Microelectronic Technologies,60 Willow Street, North Andover, MA 01845, U.S.A. 2. Department of Chemistry and Chemical Biology,Harvard University, 12 Oxford Street, Cambridge, MA 02138, U.S.A.

Nickel silicide (NiSi) is emerging as the choice material for contact applications in

semiconductor device processing for the 65nm technology node and beyond. As

the dimensions of microelectronic circuits are being reduced, the non-conformal

nature of sputtered Ni contact layers has started to cause problems. Chemical

vapor deposition (CVD) and atomic layer deposition (ALD) are identified as the

methods that can produce thin conformal contact layers (<10 nm). In this

presentation we demonstrate the effectiveness of novel nickel amidinate (Ni AMD)

as a good precursor in both ALD and CVD Ni thin films due to its high thermal

stability and high reactivity. Ni AMD has acceptable vapor pressure (> 0.1 Torr at

90 ºC) for both ALD and CVD applications. Its solubility in common commercial

solvents is excellent, which allows it to be used in direct liquid injection (DLI)

mode. Our results confirm that when this precursor reacts with ammonia as

second reagent in ALD, it readily forms Ni3N films. These NiNx films can be

converted to conductive NiSi films with annealing under reducing environment

such as using hydrogen. The conformality of both ALD and CVD films was

confirmed inside holes with 40: aspect ratio.

ALD

dC

VDfN

iNU

iA

LD a

ndC

VD o

fNiN

Usi

ngN

icke

l Am

idin

ate

Sour

ce

Huaz

hi L

i and

Deo

She

nai

Dow

Ele

ctro

nic

Mat

eria

ls,

The

Dow

Che

mic

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ompa

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orth

A

ndov

er, M

A 0

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eng

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d Ro

y G

ordo

nDe

pt o

f Che

mist

ry a

nd C

hem

ical

Bio

logy

, H

dU

iit

Cb

idM

A02

138

Harv

ard

Univ

ersit

y, C

ambr

idge

, MA

021

38

July

19,

200

920

09D

Elt

iM

ti

l20

09D

owEl

ectr

onic

Mat

eria

ls

Bac

kgro

und

and

Mot

ivat

ion

for A

LD/C

VD N

iSi

Met

al g

ate

Sour

ceD

rain

Cha

nnel

Hig

h k

oxid

e

•NiS

i is

wid

ely

used

in C

MO

S fo

r sou

rce

and

drai

n co

ntac

t met

al.

•NiS

i offe

rs th

e ad

vant

age

of s

ubst

antia

lly lo

w re

sist

ance

than

oth

er m

etal

s.

•With

the

com

plex

ity o

f str

uctu

res

invo

lved

at 3

2 nm

and

bey

ond,

•

ALD

is c

onsi

dere

d as

pre

ferr

ed te

chni

que

than

CVD

for N

iSi

•G

ood

prec

urso

rs o

f acc

epta

ble

stab

ility

and

reac

tivity

are

nee

ded

•B

ette

rpre

curs

ors

need

edfo

rdep

ositi

ons

bybo

thA

LDan

dC

VDB

ette

rpre

curs

ors

need

edfo

rdep

ositi

ons

bybo

thA

LDan

dC

VD•M

ost o

f the

com

mer

cial

Ni p

recu

rsor

s ha

ve li

mite

d st

abili

ty a

nd re

activ

ity

•e.

g. N

i(PF 3

) 4, N

i(CO

) 4an

d N

i(aca

c)2.

•New

ALD

/CVD

resu

lts u

sing

NiA

MD

pre

curs

or a

re p

rese

nted

in th

is w

ork

Ni A

mid

ina

te

Pr

ec

ur

so

r f

or

AL

D

an

d C

VD

1000

0.00

TGA

of N

i-AM

DVa

por P

ress

ure

Cur

ve fo

r Ni-A

MD

1000

.00

ssure (mtorr)

100.0

0

Vapor Pres

10.00

5060

7080

9010

011

012

013

0Te

mper

ature

Cen

tigra

de

•Lo

w m

eltin

g po

int s

olid

(87

ºC) w

ith g

ood

shel

f life

and

ther

mal

sta

bilit

y•

Hig

h va

por p

ress

ure

(>1

Torr

@ 9

0 ºC

) offe

rs a

dvan

tage

of h

igh

thro

ughp

ut•

Ne g

ligib

le e

vapo

ratio

n re

sidu

e as

con

firm

ed b

y TG

Ag

gp

y

Ther

mal

Sta

bilit

y of

Ni A

MD

by

AR

C

ARC

Resu

lts: N

ickle

amidi

nate

[Ni_a

md.da

t]

Acc

eler

atin

g R

ate

Cal

orim

etry

(AR

C) S

tudi

es o

n N

i-AM

D

250

300

350

ees C)

200

250

Onse

t Tem

p. (d

eg C

):22

0.24

48

100

150

200

le Temp. (Degre

100

150

Pressure (psia)

050100

020

040

060

080

010

0012

0014

0016

0018

00

Samp

050

000

0060

080

000

000

0060

080

0

Time (

Minu

tes)

•Ons

et o

f the

rmal

dec

ompo

sitio

n is

repo

rted

at a

roun

d 22

0 º C

•Hal

f life

(t1/

2) a

t 130

ºC w

as fo

und

to b

e 96

hrs

by

NM

R s

tudi

es

AL

D a

nd

CV

D N

i Co

nd

itio

ns

ALD

/CV

Dco

nditi

ons

Bub

bler

tem

pera

ture

for A

LD/C

VD: 9

0-10

0 C

(mol

ten

sour

ce)

ALD

/CVD

subs

trat

ete

mpe

ratu

re:2

75C

.

/Cco

dto

s

ALD

/CVD

subs

trat

ete

mpe

ratu

re:2

75C

.In

ALD

mod

e, th

e se

cond

reac

tant

is N

H3.

In C

VD m

ode,

the

seco

nd re

acta

nt is

H2/N

H3.

Silic

idat

ion

carr

ied

ot

sing

rapi

dth

erm

alan

neal

ing

(RTA

)Si

licid

atio

nca

rrie

dou

t usi

ngra

pid

ther

mal

anne

alin

g(R

TA):

at 5

50 ºC

, usi

ng fo

rmin

g ga

s at

5 T

orr f

or 5

min

.

Phy

sica

lpro

perti

es o

f Ni-A

MD

Nam

eN

icke

l Bis

(N,N

’-dite

rtial

buty

lace

tam

idin

ate)

XP n

umbe

rXP

-072

39

Form

ula

BD

TBA

Ni,

Ni(t

Bu 2

-am

d)2,

((tB

u)N

C(C

H3)

N(tB

u)2N

i

yp

p

((tB

u)N

C(C

H3)

N(tB

u)2N

i

Mol

ecul

ar W

eigh

t39

7.27

App

eara

nce

brow

n so

lid

m.p

. (ºC

)87

o C

Den

sit

(g/m

l)0

65D

ensi

ty(g

/ml)

0.65

Ther

mal

Sta

bilit

ygr

eate

r tha

n 2

mon

ths

at 9

0 o C

She

lf lif

eM

ore

than

12

mon

th

ALD

of N

iN0.

1on

Sia

nd S

iO2

160

200

onSi

SiO

80120

160

Thickness (A)

onSi

onSi

O2

040

020

040

060

080

010

00

T

ALD

rate

;~

0.2

Å/c

ycle

# of

cyc

les

ALD

rate

;~

0.6

Å/c

ycle

(bef

ore

60 c

ycle

s)0

2Å

/cyc

le(a

fter6

0cy

cles

)y

~0.

2Å

/cyc

le(a

fter6

0cy

cles

)

Hig

her g

row

th ra

te is

ach

ieve

d in

itial

ly o

n Si

O2

subs

trat

eth

an o

n Si

.A

fter~

60cy

cles

com

para

ble

grow

thra

tes

are

achi

eved

onSi

and

SiO

Afte

r~60

cycl

es,c

ompa

rabl

egr

owth

rate

sar

eac

hiev

edon

Sian

dSi

O2.

XRD

of A

LD N

iN0.

1on

Si

Si (111)

i (220)

(121)

310)

NiS

NiSi

NiSi(

NiSi (3

)

Post

Ann

eal,

NiS

i

Ni (101)

As

Dep

osite

d, N

i

Nitr

ogen

exp

elle

d an

d pu

re N

iSi f

orm

edSh

eet R

esist

ance

of N

iSi a

fter a

nnea

ling

~4.2

/sq

Resis

tivity

of N

iSi ~

32-c

m (l

owes

t rep

orte

d va

lue

~14

-cm

)

Dep

ositi

on R

ate

of C

VD N

iNx

Film

s

Slop

e =>

5 n

anom

eter

s pe

r min

ute

Inte

rcep

t~0

=>no

nucl

eatio

nde

lay

Inte

rcep

t~0

=>no

nucl

eatio

nde

lay

Com

posi

tion

of C

VD N

iNx

Film

s by

RB

S

Ni 3.

2N

Ni 11

7N

Ni

11.7

Hfl

60N

Hfl

Nflo

=60

sccm

Ni

H2

flow

= 6

0 –

NH

3flo

wN

2flo

w=

60sc

cm

Co

mp

le

te

St

ep

Co

ve

ra

ge

(>5

0:1

ho

le

s)

by

CV

D

CV

D N

iSi D

ep

th

Pr

of

ile

by

X

PS

Si2p

Ni2p

3/2

C1s

O1s

N1s

405s

585s

135s

225s

405s

Asde

p

15s

45s

1000

800

600

400

200

0B

indi

ng E

nerg

y (e

V)

Asde

p

•XPS

con

firm

s hi

gh p

urity

NiS

i film

s w

ith n

o C

, N o

r O im

purit

ies

Sum

mar

y

Ni-A

MD

has

suf

ficie

nt v

apor

pre

ssur

e, g

ood

ther

mal

sta

bilit

y, a

nd

exce

llent

reac

tivity

for A

LD a

nd C

VD

app

licat

ions

.

ALD

and

CV

D u

sing

NH

3le

ad to

Ni r

ich

NiN

xon

Si,

whi

ch c

an b

e co

nver

ted

to p

ure

NiS

i afte

r ann

ealin

g un

der N

2.

Com

plet

e st

ep-c

over

age

is a

chie

ved

in C

VD

NiN

xw

ith 5

0:1

aspe

ct

ratio

hol

es a

t sig

nific

antly

hig

her g

row

th ra

tes

than

in A

LD m

ode.

Hig

h pu

rity

of N

iSi f

ilms,

as

dem

onst

rate

d by

XP

S, c

onfir

m N

I-AM

D

to b

e a

bette

r sou

rce

for A

LD a

nd C

VD

of N

i-com

pris

ing

film

s