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Har
vard
Uni
vers
ity
New
Pre
curs
ors
for A
LD
of H
igh-
k D
iele
ctric
s
Roy
G. G
ordo
n,Je
an-S
ébas
tien
Lehn
, Yiq
unLi
u,
Kyo
ung
H. K
im, Z
heng
wen
Li a
nd M
icha
el C
oulte
rH
arva
rd U
nive
rsity
Cam
brid
ge, M
A
Hua
zhiL
i, R
alph
Pug
h an
d D
eoSh
enai
Roh
m a
nd H
aas
Com
pany
Nor
th A
ndov
er, M
A
Har
vard
Uni
vers
ity
ALD
HfO
2fr
om s
tabl
e H
fam
idin
ate
prec
urso
rs
Stab
le, a
mor
phou
s hi
gh-k
die
lect
rics
=> L
aLuO
3ha
s th
e be
st p
rope
rtie
s
Vola
tile
Prec
urso
rs fo
r Lan
than
um O
xide
ALD
of L
a 2O
3an
d La
AlO
3
Vola
tile
Prec
urso
rs fo
r Lut
etiu
m O
xide
Out
line
Har
vard
Uni
vers
ity
Hig
h-k
HfO
2or
ZrO
2w
ith v
ery
low
ele
ctric
al le
akag
e ne
eded
Why
Mor
e St
able
Hfa
nd Z
rPre
curs
ors?
Car
bon
impu
rity
in fi
lms
incr
ease
s le
akag
e
Ther
mal
dec
ompo
sitio
n of
org
anic
pre
curs
ors
adds
C to
film
s
Ther
mal
dec
ompo
sitio
n de
stro
ys u
nifo
rmity
and
con
form
ality
Dep
ositi
on T
~ 3
50 o C
nee
ded
for H
fAlO
xw
ith A
LD A
l 2O3
Hfa
lkyl
amid
epr
ecur
sors
dec
ompo
se to
o qu
ickl
y at
350
o C
Har
vard
Uni
vers
ity
Haf
nium
tetr
akis
(N,N
’-dim
ethy
lform
amid
inat
e)
Neg
ligib
le re
sidu
e af
ter T
G
CH
3
N
NC
H3
H
H3C
N
N CH
3H
CH
3N
N CH
3H
CH
3
N
NH
3C
H
Hf
=> S
uffic
ient
vol
atili
ty a
nd th
erm
al s
tabi
lity
for A
LD
TG d
ata
for
Hf(M
e 2-fm
d)4
Tem
pera
ture
(oC
)
Remaining mass (%)
187
o C
Har
vard
Uni
vers
ityHaf
nium
Am
idin
ates
CH
3
N
NC
H3
R
H3C
N
N CH
3R
CH
3N
N CH
3R
CH
3
N
NH
3C
R
Hf
bmd
pmd
amd
fmd
187
141
H
246
<20
CH
2CH
2CH
3
251
80C
H2C
H3
221
171
CH
3
TG T
½o C
Mel
ting
Poi
nt,o
CR
R =
CH
2CH
2CH
3(p
ropy
l) is
a li
quid
Hfp
recu
rsor
20 o C
R =
H is
the
mos
t vol
atile
; liq
uid
in b
ubbl
er >
141
o CSo
lid a
t 20
o C, s
olub
le fo
r use
in d
irect
liqu
id in
ject
ion
Har
vard
Uni
vers
ity
Ther
mal
Sta
bilit
y of
Hfa
nd Z
rPre
curs
ors
No
deco
mpo
sitio
n of
Hf
or Z
ram
idin
ates
dur
ing
1000
hou
rs a
t 200
o C:
Hfa
nd Z
ram
ides
com
plet
ely
deco
mpo
sed
in a
few
hou
rs
at 2
00 o C
:
Prec
urso
rs d
isso
lved
in m
esity
lene
-d12
, hea
ted,
an
d N
MR
spe
ctra
take
n pe
riodi
cally
020406080100
120
02
46
810
1214
Tim
e (h
)
% of complex remaining
Zr(N
Me2
)4Zr
(NEt
2)4
Hf(N
Me2
)4H
f(NM
eEt)4
020406080100
120
020
040
060
080
010
00Ti
me
(h)
% of complex remainingZr
(MM
M)4
Hf(M
MM
)4
Hf(M
EM)4
Zr(M
e 2-a
md)
4H
f(Me 2
-am
d)4
Hf(M
e 2-p
md)
4
Har
vard
Uni
vers
ity
Ther
mal
Sta
bilit
y of
Hfa
nd Z
rAm
idin
ates
No
deco
mpo
sitio
n du
ring
140
hour
s at
250
o CD
ecom
posi
tion
afte
r ~2
00 h
ours
at 2
80 o C
=> H
fand
Zra
mid
inat
es m
uch
mor
e st
able
than
am
ides
020406080100
120
050
100
150
200
250
300
350
Tim
e (h
)
% of complex remaining
Zr(M
MM
)4
Hf(M
MM
)4
020406080100
120
020
4060
8010
012
014
0Ti
me
(h)
% of complex remaining
Zr(M
MM
)4
Hf(M
MM
)4
Zr(M
e 2-a
md)
4H
f(Me 2
-am
d)4
Zr(M
e 2-a
md)
4H
f(Me 2
-am
d)4
Har
vard
Uni
vers
ity
Vapo
rizat
ion
Rat
es o
f Haf
nium
Am
idin
ates
Hig
hest
rate
with
Hft
etra
kis(
N,N
’-dim
ethy
lform
amid
inat
e)
=> H
igh
evap
orat
ion
rate
s fr
om th
erm
ally
sta
ble
liqui
ds
Har
vard
Uni
vers
ity
ALD
of H
fO2
from
Am
idin
ate
Prec
urso
rs
ALD
Con
ditio
ns
Typi
cal b
ubbl
er te
mpe
ratu
res
100-
150
o C(m
p 14
1 o C
)
ALD
with
H2O
sel
f-lim
iting
at ~
0.1
nm p
er c
ycle
ALD
“w
indo
w”
~150
to ~
400
o C
Elec
tric
al P
rope
rtie
s (n
on-o
ptim
ized
)
Die
lect
ric c
onst
ant >
16
Bre
akdo
wn
field
~6
MV/
cm
Har
vard
Uni
vers
ity
Stab
le A
mor
phou
s H
igh-
k D
iele
ctric
s
2.5
2.0
22D
yScO
3
4.4
3.5
3.9
SiO
2
4.9
2.8
8A
l 2O3
2.1
2.1
32La
LuO
3
2.5
2.0
22G
dScO
3
2.6
2.0
20La
2Hf 2O
7
3.2
1.9
18La
AlO
3
3.4
1.5
12H
fSiO
4
Val
ence
band
offs
etC
ondu
ctio
nba
nd o
ffset
k
=> L
aLuO
3ha
s th
e be
st p
rope
rtie
s!
Har
vard
Uni
vers
ity
Adv
anta
ges
of L
aLuO
3as
hig
h-k
diel
ectr
ic
Hig
h di
elec
tric
cons
tant
(k~3
2) fo
r am
orph
ous
pha
se
Sha
rp in
terfa
ce w
ith S
i, an
d no
low
-k in
terla
yer
Sta
ys a
mor
phou
s an
d do
esn’
t for
mal
loys
with
Sio
r Ge
afte
r res
pect
ive
S/D
act
ivat
ion
anne
als
Bot
h ba
nd o
ffset
s w
.r.t S
iare
larg
e (2
.1 e
V),
help
ing
to a
chie
ve lo
w le
akag
e cu
rren
ts
Har
vard
Uni
vers
ity
Am
idin
ate
Prec
urso
rs fo
r Lan
than
ides
Ln
NN
NN
NN
R2
R1
R2
R2
R1
R1
R3
R3
R3
The
R1
and
R2
are
alky
l gro
ups:
isop
ropy
l, te
rt-b
utyl
, eth
yl, e
tc.
The
choi
ces
of R
naf
fect
the
vola
tility
, rea
ctiv
ity a
nd s
tabi
lity.
R3
can
be a
n al
kyl g
roup
or h
ydro
gen
Har
vard
Uni
vers
ity
Ther
mog
ravi
met
ricA
naly
sis
of
Lant
hanu
m A
mid
inat
es
NH C
N
N CH
NN
HCN
La
NC
N
N CN
NCN
LaCH
3
CH
3H
3C
NC
N
N CN
NCN
LaCH
3
CH
3H
3CH3C
CH
3 CH
3
CH
3C
H3
H3C
=> V
apor
izat
ion
tem
pera
ture
incr
ease
s w
ith m
olec
ular
mas
s
Har
vard
Uni
vers
ity
Vapo
r Pre
ssur
es o
f Lan
than
um P
recu
rsor
s
=> L
a(iP
r 2-fm
d)3
is m
ost
vola
tile
La c
ompo
und
know
n,
60 m
Torr
at 1
00 o C
La(iP
rCp)
3
NH C
N
N CH
NN
HCN
La
Har
vard
Uni
vers
ity
ALD
of L
a 2O
3 => 0
.16
nm p
er c
ycle
=> n
eglig
ible
del
ay
in n
ucle
atio
n on
SiH
NH C
N
N CH
NN
HCN
La
tris
(N,N
’-diis
opro
pyl-
form
amid
inat
o)la
ntha
num
(i Pr 2
-fmd)
3La
Prec
urso
rs:
H2O
and
Har
vard
Uni
vers
ity
Gro
wth
per
La
Cyc
le fo
r ALD
LaA
lO3
Bub
bler
tem
pera
ture
90
to 1
20 o C
Subs
trat
e te
mpe
ratu
re 3
00 o C
Gro
wth
eve
n at
bub
bler
te
mpe
ratu
re <
100
o C
=> A
LD s
atur
atio
n at
0.
08 n
m p
er L
a cy
cle
NH C
N
N CH
NN
HCN
La
tris
(N,N
’-diis
opro
pyl-
form
amid
inat
o)la
ntha
num
(i Pr 2
-fmd)
3La
Prec
urso
rs:
Me 3
Al,
H2O
and
120
o C11
0o C
100
o C90
o C
Har
vard
Uni
vers
ity
Com
posi
tion
of A
LD L
a xA
l 1-xO
3/2
Gro
wth
con
ditio
ns:
Bub
bler
tem
pera
ture
120
o CSu
bstr
ate
tem
pera
ture
300
o C
=> C
ompo
sitio
n co
ntro
l by
cha
ngin
g ra
tio o
f pr
ecur
sor d
oses
=> 2
x a
s m
any
Al a
tom
s as
La
atom
s pe
r dos
e
NH C
N
N CH
NN
HCN
La
tris
(N,N
’-diis
opro
pyl-
form
amid
inat
o)la
ntha
num
(i Pr 2
-fmd)
3La
Prec
urso
rs:
Me 3
Al,
H2O
and
Har
vard
Uni
vers
ity
Prec
urso
r Rea
ctiv
ity w
ith S
iHSu
rfac
e by
IR
=> C
ompl
etel
y un
iform
sur
face
cov
erag
e by
La
amid
inat
e
Hfa
lkyl
amid
eon
ly
reac
ts w
ith h
alf o
f th
e Si
-H b
onds
on
the
surf
ace
even
af
ter m
any
cycl
es
La a
mid
inat
e re
acts
w
ith n
early
all
the
Si-H
bon
ds in
onl
y 3
cycl
es
Det
ails
of t
he in
frar
ed s
pect
ra w
ere
give
n in
a p
aper
this
mor
ning
by
J. K
won
, M. D
ai, E
. Lan
gere
is, Y
. Cha
bal,
K.-H
. Kim
and
R. G
. Gor
don.
Har
vard
Uni
vers
ity
TEM
sof
ALD
LaA
lO3an
d G
dScO
3
=> S
harp
inte
rfac
es w
ith s
ilico
n w
ithou
t int
erla
yers
=> U
nifo
rm n
ucle
atio
n an
d th
ickn
ess
Har
vard
Uni
vers
ity
Leak
age
Cur
rent
thro
ugh
ALD
La 2
O3
Vapo
r sou
rce:
a s
olut
ion
of th
e La
pre
curs
or (m
p 19
4 o C
)va
poriz
ed w
ith a
n M
KS
MD
D s
yste
m
Low
leak
age
curr
ent s
imila
r to
film
s m
ade
from
a b
ubbl
er.
=> n
eglig
ible
car
bon
cont
amin
atio
n fr
om s
olve
nt
Har
vard
Uni
vers
ity
Ther
mal
Gra
vim
etric
Ana
lysi
s of
Lu
tetiu
m tr
is(N
,N’-d
iisop
ropy
lace
tam
idin
ate)
Evap
orat
ion
with
neg
ligib
le re
sidu
e
=> S
uffic
ient
vol
atili
ty a
nd th
erm
al s
tabi
lity
for A
LD
NC
N
N CN
NCN
LuCH
3
CH
3H
3C
Har
vard
Uni
vers
ity
Ther
mal
Gra
vim
etric
Ana
lyse
s of
La
ntha
num
and
Lut
etiu
m A
mid
inat
es
NH C
N
N CH
NN
HCN
LuN
CN
N CN
NCN
LuCH
3
CH
3H
3C
NC
N
N CN
NCN
LuCH
3
CH
3H
3CH3C
CH
3 CH
3
CH
3C
H3
H3C
=> L
u am
idin
ates
are
slig
htly
mor
e vo
latil
e th
an L
a am
idin
ates
Har
vard
Uni
vers
ity
ALD
of L
u 2O
3an
d La
LuO
3
ALD
exp
erim
ents
and
film
cha
ract
eriz
atio
n ar
e un
derw
ay. .
. .
Har
vard
Uni
vers
ity
Con
clus
ions
Hfa
mid
inat
es a
re m
ore
stab
le th
an H
fam
ides
Hfa
mid
inat
es a
re s
uita
ble
as A
LD p
recu
rsor
s
La a
nd L
u am
idin
ates
are
vol
atile
ALD
pre
curs
ors
LaLu
O3
is a
ver
y pr
omis
ing
high
-k d
iele
ctric
Cur
rent
wor
k on
ALD
of L
aAlO
3, Lu
2O3
and
LaLu
O3
Har
vard
Uni
vers
ity
Am
idin
ate
prec
urso
rs s
uppl
ied
by R
ohm
and
Haa
s C
ompa
ny
MD
D li
quid
del
iver
y sy
stem
sup
plie
d by
MK
S In
stru
men
ts, I
nc.
Infr
ared
dat
a fr
om J
inhe
eK
won
, Min
Dai
, Erik
Lan
gere
is,
Lesz
ekW
ielu
nski
and
Yves
J. C
haba
l, R
utge
rs U
nive
rsity
Supp
orte
d in
par
t by
the
US
Nat
iona
l Sci
ence
Fou
ndat
ion
Ack
now
ledg
emen
ts
