Precursors with Metal-Nitrogen Bonds for ALD of Metals, Nitrides and Oxides

Roy Gordon Gordon@chemistry.harvard.edu

Harvard University, Cambridge, MA

Abstract

To achieve ALD’s unique characteristics, ALD precursors must have very specific properties: high and self-limited reactivity with surfaces, high thermal stability and adequate volatility. In addition, their reaction byproducts must not react with the deposited films or the substrates. Precursors with metal-nitrogen bonds have been found to be particularly effective for ALD of metal oxides, nitrides and pure metals: dialkylamides of Al, Sn, Ti, Zr, Hf, Nb and Ta; dialkylamide-alkylimide mixed ligand compounds of Nb, Ta, Mo and W; dialkylacetamidinates of Mg, Ca, Sc, Ti, V, Cr, Mn, Fe, Ru, Co, Rh, Ni, Cu, Bi, Y, La and the other lanthanide metals. As one example, new precursors for ALD of nickel will be presented. Other examples of the materials made from these precursors include high-k dielectric insulators HfO2, HfON, HfSiON and LaAlO3; electrical conductors of Cu; conducting Cu diffusion barriers of WN and TaNx;metals Co and Ru that promote strong adhesion between Cu and nitride diffusion barriers; magnetic metals Fe, Co and Ni and their magnetoresistive combinations with Al2O3 or MgO; photonic crystals of high-dielectric constant material Ta3N5; insulating AlN and Hf3N4 for passivating Ge surfaces.

Har

vard

Uni

vers

ity

Roy

G. G

ordo

nHa

rvar

d Un

iver

sity

Cam

brid

ge, M

A

Har

vard

Uni

vers

ity

How

man

y pr

ecur

sors

are

nee

ded?

Che

mic

al T

ypes

of P

recu

rsor

s fo

r ALD

Prec

urso

rs w

ith M

etal

-Nitr

ogen

Bon

ds

Met

als:

Ni,

Cu

Nitr

ides

: Hf 3

N4

=> H

fN

Oxi

des:

Lan

than

ides

, Tra

nsiti

on m

etal

s

Out

line

Har

vard

Uni

vers

ity

How

Man

y Pr

ecur

sors

Nee

ded

for A

LD?

Har

vard

Uni

vers

ity

Num

ber o

f Ele

men

ts in

a C

ompu

ter C

hip

Har

vard

Uni

vers

ity

•Suf

ficie

nt v

olat

ility

(> 0

.1 T

orr)

•Suf

ficie

nt th

erm

al s

tabi

lity

•Hig

h, s

elf-l

imite

d re

activ

ity w

ith s

ubst

rate

s

•Hig

h, s

elf-l

imite

d re

activ

ity w

ith th

e su

rfac

e pr

epar

ed b

y th

e ot

her p

recu

rsor

•Pre

curs

ors

and

bypr

oduc

ts th

at d

on’t

etch

or

adso

rb o

n th

e fil

m o

r the

sub

stra

te

Crit

eria

for A

LD P

recu

rsor

s

Har

vard

Uni

vers

ity

Type

s of

Pre

curs

ors

for A

LD M

N

R

Alky

limid

es

Har

vard

Uni

vers

ity

Lim

itatio

ns o

f Pre

curs

or T

ypes

for A

LD

Har

vard

Uni

vers

ity

Rea

ctiv

ity o

f Haf

nium

Pre

curs

ors

Hf(N

Me 2

) 4ha

s hi

ghes

t rea

ctiv

ity w

ith w

ater

and

am

mon

ia,

lead

ing

to th

e•P

ures

t film

s (<

0.1%

impu

ritie

s)•S

moo

thes

t film

s (r

ough

ness

sam

e as

sub

stra

te)

•Hig

hest

ste

p co

vera

ge (>

200:

1 as

pect

ratio

s)•L

owes

t dep

ositi

on te

mpe

ratu

re (~

50 o C

)

Hf

NM

e 2M

e 2N

NM

e 2

NM

e 2

Hf

Cl

Cl

Cl

Cl

Hf

OBu

tBu

t O

OBu

t

OBu

t

>>

Haf

nium

dim

ethy

lam

ide

Haf

nium

chl

orid

eH

afni

um te

rt-bu

toxi

de

Har

vard

Uni

vers

ity

Prec

urso

rs w

ith N

itrog

en-B

ased

Lig

ands

HH

eL

i B

e B

C

N

O

F N

e N

a M

g A

l Si

P

S C

l A

r K

Ca

Sc

Ti

V

Cr

Mn

Fe

Co

Ni

Cu

Zn

Ga

Ge

As

Se

Br

Kr

Rb

Sr

Y

Zr

Nb

Mo

Tc

Ru

Rh

PdA

g C

d In

Sn

Sb

T

e I

Xe

Cs

Ba

La

Hf

Ta

W

Re

Os

Ir

Pt

Au

Hg

Tl

Pb

Bi

Po

At

Rn

Fr

Ra

Ac

C

e Pr

N

d Pm

Sm

Eu

Gd

Tb

Dy

Ho

Er

Tm

Y

b L

u

Th

Pa

U

Np

Pu

Am

C

m

Bk

Cf

Es

Fm

Md

No

Lr

Gre

en =

at l

east

one

vol

atile

N-b

ased

pre

curs

or k

now

n

Har

vard

Uni

vers

ity

ALD

of t

rans

ition

met

als

from

am

idin

ate

prec

urso

rs

1 Zhe

ngw

en L

i, A

LD 2

005,

Tue

sday

1:4

5

2 Hua

zhi L

i, A

LD 2

005,

Tue

sday

2:1

5

Har

vard

Uni

vers

ity

Stru

ctur

es o

f 2 N

i ace

tam

idin

ate

prec

urso

rs

Har

vard

Uni

vers

ity

Har

vard

Uni

vers

ity

Nic

kel P

recu

rsor

s w

ith V

ario

us A

lkyl

Gro

ups

100 80 60 40 20

5010

015

020

025

030

035

040

0

R

R

esid

ue(%

)M

e

0.

7E

t

0.

5i P

r0.

8P

h

3.

6

Weight (%)

Tem

pera

ture

(°C

)

t Bu N t BuN

R

t BuNt Bu N

RN

i

0

Har

vard

Uni

vers

ityALD

of N

icke

l on

Si

95 ºC

sou

rce

(liqu

id)

270º

C s

ubst

rate

Gro

wth

: ~0

.2 Å

/cyc

le

with

eith

er H

2or

NH

3

RB

S sp

ectr

um (7

00 c

ycle

s)

Thic

knes

s ~

14 n

m

050100

150

020

040

060

080

0#

of c

ycle

s

Thickness (A)

020

040

060

080

010

00C

hann

el

05101520253035 NormalizedYield

0.5

1.0

1.5

Ener

gy(M

eV)

Har

vard

Uni

vers

ity

XR

D o

f Nic

kel o

n S

i10

0 80 60 40 20 0

50

4540

3530

2 th

eta

( de

gree

s )

NiSi(111)

NiSi(220)

NiSi(121)

NiSi(310)

Ni (101)

Ann

eale

d, N

iSi

As

Dep

osite

d, N

i

Sili

cida

tion

usin

g R

TA :

550

ºC, 5

min

in fo

rmin

g ga

s (lo

w p

ress

ure)

She

et re

sist

ance

of N

i as

depo

site

d ~

90

/�, 1

4 nm

She

et R

esis

tanc

e of

NiS

iafte

r ann

ealin

g ~

4.2

/�

Har

vard

Uni

vers

ity

ALD

of N

icke

l on

SiO

2

Dep

ositi

on C

ondi

tions

: 270

ºC/ 9

5 ºC

Gro

wth

bef

ore

60 c

ycle

s ~

0.6

Å/ c

ycle

Gro

wth

afte

r 60

cycl

es ~

0.2

Å/c

ycle

Res

istiv

ity~

68

-cm

( 90

0 cy

cle,

18

nm,

She

et R

esis

tanc

e ~

38

/�)

RB

S s

pect

rum

for 7

00

cycl

es

Thic

knes

s ~

14 n

m

200

300

400

500

600

700

800

Cha

nnel

051015202530 NormalizedYield

0.4

0.6

0.8

1.0

1.2

1.4

Ener

gy(M

eV)

020406080100

120

140

160

180

200

020

040

060

080

010

00

# of

cyc

les

Thickness (A)

Har

vard

Uni

vers

ity

TEM

of N

ucle

atio

n of

Nic

kel o

n S

iO2

Gro

wth

at 2

70 ºC

, 30

cyc

les

Thic

knes

s by

RB

S ~

1.7

nm

Ave

rage

gra

in d

iam

eter

5-1

0 nm

Har

vard

Uni

vers

ity

Prec

urso

rs fo

r ALD

of C

oppe

r Film

sC

u(I)

N,N

’-di-s

ec-b

utyl

acet

amid

inat

e[C

u(se

c-Bu

2-am

d)] 2

Mel

ting

poin

t: 77

o CVa

por p

ress

ure

of li

quid

: 95

o C/0

.2 T

orr

Rea

ctiv

e to

mol

ecul

ar h

ydro

gen,

H2

0.1

to 2

Ang

stro

m p

er c

ycle

Zhen

gwen

Li, A

LD 2

005

(Tue

sday

, 1:4

5pm

)

1 -2

SiO

2, A

l 2O3,

HfO

2

0.1

-0.2

Ru

0.4

-0.5

Co

0.4

-0.5

Cu

Gro

wth

(A/c

ycle

)Su

bstr

ate

Har

vard

Uni

vers

ity

TEM

Stu

dy o

f Cu

Nuc

leat

ion

on S

iO2

and

on C

o

2 nm

Cu,

man

y sm

all n

ucle

iel

ectr

ical

ly c

onne

cted

50 A

LD c

ycle

s of

Cu/

H2

on a

Co/

SiO

2su

bstr

ate:

30 A

LD c

ycle

s of

Cu/

H2

on a

SiO

2su

bstr

ate

:

6 nm

Cu,

few

larg

e nu

clei

not e

lect

rical

ly c

onne

cted

40/�

for 4

nm

thic

k C

u se

ed la

yer

Har

vard

Uni

vers

ity

ALD

of m

etal

nitr

ides

from

nitr

ogen

-bas

ed li

gand

s

1 Zhe

ngw

en L

i, A

LD 2

005

(Tue

sday

1:4

5pm

)

Har

vard

Uni

vers

ity

ALD

of H

afni

um N

itrid

es, H

f 3N

4an

d H

fN

Jill

S.B

ecke

r, E

sthe

r K

im a

nd R

oy G

.Gor

don

Chem

. Mat

er.(

2004

), 16

, 349

7.

Top

Botto

m

60 n

m

60 n

m

Top

Botto

m

60 n

m

60 n

m

Top

Botto

m

60 n

m

60 n

m

Har

vard

Uni

vers

ity

Con

vers

ion

of In

sula

ting

Hf3N

4to

Met

allic

HfN

2030

4050

60050100

150

Si

As d

epos

ited

900

o C

1050

o C

HfN (220)

HfN (200)

HfN ( 111)

CPS

2

Har

vard

Uni

vers

ity

New

Lan

than

ide

Prec

urso

rs

Mos

t vol

atile

La

com

poun

d kn

own

(~0.

1 To

rr/1

30 o C

)H

igh

ther

mal

sta

bilit

y (~

300

o Cin

ALD

reac

tor)

Initi

ates

gro

wth

on

HF-

last

sili

con,

EO

T ~

1nm

, < m

Ale

akag

e

R =

isop

ropy

l

La

NN

NN

NN

CC

CR

R

RR

RR

CH

3

CH

3H

3C

Har

vard

Uni

vers

ityTG o

f Yttr

ium

Am

idin

ates

Har

vard

Uni

vers

ity

Mod

els

for Y

ttriu

m A

mid

inat

es

Har

vard

Uni

vers

ity

ALD

of m

etal

(III)

oxid

es fr

om a

mid

inat

epr

ecur

sors

*Phi

lippe

de

Rou

ffig

nac,

ALD

200

5 (W

edne

sday

B 8

:45

am)

# Kyo

ung

Kyo

ung --

hahaK

im, A

LD 2

005

(Wed

nesd

ay B

8:1

5 am

)

Har

vard

Uni

vers

ity

Mod

els

for L

anth

anum

and

Sca

ndiu

m A

mid

inat

es

Har

vard

Uni

vers

ity

Har

vard

Uni

vers

ity

ALD

of m

etal

(II) o

xide

s fro

m a

mid

inat

es

Har

vard

Uni

vers

ity

Har

vard

Uni

vers

ityAck

now

ledg

emen

ts