Atomic layer deposition (ALD) of ruthenium (Ru) is being investigated for next generation interconnects and conducting liners for copper metallization. However, integration of ALD Ru with diffusion barrier refractory metal nitrides, such as tantalum nitride (TaN), continues to be a challenge due to its slow nucleation rates. Here, we demonstrate that an ultraviolet-ozone (UV-O3) pretreatment of TaN leads to an oxidized surface that favorably alters the deposition characteristics of ALD Ru from islandlike to layer-by-layer growth. The film morphology and properties are evaluated via spectroscopic ellipsometry, atomic force microscopy, electrical sheet resistance measurements, and thermoreflectance. We report a 1.83 nm continuous Ru film with a roughness of 0.19 nm and a sheet resistance of 10.8 KΩ/□. The interface chemistry between TaN and Ru is studied by x-ray photoelectron spectroscopy. It is shown that UV-O3 pretreatment, while oxidizing TaN, enhances Ru film nucleation and limits further oxidation of the underlying TaN during ALD. An oxygen “gettering” mechanism by TaN is proposed to explain reduced oxygen content in the Ru film and higher electrical conductivity compared to Ru deposited on native-TaN. This work provides a simple and effective approach using UV-O3 pretreatment for obtaining sub-2 nm, smooth, and conducting Ru films on TaN surfaces.

1.
C.
Arenas
,
G.
Herrera
,
E.
Muñoz
, and
R. C.
Munoz
,
Mater. Res. Express
8
,
015026
(
2021
).
2.
C. C.
Yang
,
S.
Cohen
,
T.
Shaw
,
P. C.
Wang
,
T.
Nogami
, and
D.
Edelstein
,
IEEE Electron Device Lett.
31
,
722
(
2010
).
3.
T.
Nogami
et al, “
High reliability 32 nm Cu/ULK BEOL based on PVD CuMn seed, and its extendibility
,” in
2010 International Electron Devices Meeting
,
San Francisco, CA, 6–8 December, 2010
(
IEEE
,
New York
,
2010
).
4.
C.
De Paula
,
N. E.
Richey
,
L.
Zeng
, and
S. F.
Bent
,
Chem. Mater.
32
,
315
(
2020
).
5.
D. Z.
Austin
,
M. A.
Jenkins
,
D.
Allman
,
S.
Hose
,
D.
Price
,
C. L.
Dezelah
, and
J. F.
Conley
,
Chem. Mater.
29
,
1107
(
2017
).
6.
Q.
Xie
et al,
Thin Solid Films
517
,
4689
(
2009
).
7.
B. H.
Choi
,
Y. H.
Lim
,
J. H.
Lee
,
Y. B.
Kim
,
H.-N.
Lee
, and
H. K.
Lee
,
Microelectron. Eng.
87
,
1391
(
2010
).
9.
10.
D.
Gall
,
J. Appl. Phys.
119
,
085101
(
2016
).
11.
D.
Gall
,
A.
Jog
, and
T.
Zhou
, “
Narrow interconnects: The most conductive metals
,” in
2020 IEEE International Electron Devices Meeting (IEDM)
,
San Francisco, CA, 2020
(
IEEE
,
New York
,
2020
), pp.
32.3.1
32.3.4
.
12.
T.
Zhou
and
D.
Gall
,
Phys. Rev. B
97
, 165406 (
2018
).
13.
D.
Gall
,
J. Appl. Phys.
127
,
050901
(
2020
).
14.
O.-K.
Kwon
,
J.-H.
Kim
,
H.-S.
Park
, and
S.-W.
Kang
,
J. Electrochem. Soc.
151
,
G109
(
2004
).
15.
S. M.
George
,
A. W.
Ott
, and
J. W.
Klaus
,
J. Phys. Chem.
100
,
13121
(
1996
).
16.
Y. H.
Park
,
M. H.
Kim
,
S. B.
Kim
,
H. J.
Jung
,
K.
Chae
,
Y. H.
Ahn
,
J.-Y.
Park
,
F.
Rotermund
, and
S. W.
Lee
,
Chem. Mater.
28
,
7268
(
2016
).
17.
C.
Feit
,
J.
Sosa
,
A.
Kostogiannes
,
M.
Chazot
,
N. G.
Rudawski
,
T.
Jurca
,
K. A.
Richardson
, and
P.
Banerjee
,
J. Vac. Sci. Technol. A
40
,
052402
(
2022
).
18.
J.
Yarbrough
,
A. B.
Shearer
, and
S. F.
Bent
,
J. Vac. Sci. Technol. A
39
,
021002
(
2021
).
19.
J.
Lee
,
J. M.
Lee
,
H.
Oh
,
C.
Kim
,
J.
Kim
,
D. H.
Kim
,
B.
Shong
,
T. J.
Park
, and
W. H.
Kim
,
Adv. Funct. Mater.
31
,
2102556
(
2021
).
20.
Z.
Gao
,
D.
Le
,
A.
Khaniya
,
C. L.
Dezelah
,
J.
Woodruff
,
R. K.
Kanjolia
,
W. E.
Kaden
,
T. S.
Rahman
, and
P.
Banerjee
,
Chem. Mater.
31
,
1304
(
2019
).
21.
J. R.
Schneider
,
C.
de Paula
,
J.
Lewis
,
J.
Woodruff
,
J. A.
Raiford
, and
S. F.
Bent
,
Small
18
,
e2105513
(
2022
).
22.
D. K.
Schroder
,
Semiconductor Material and Device Characterization
(
Wiley
,
New York
,
2015
).
23.
R. L.
Puurunen
and
W.
Vandervorst
,
J. Appl. Phys.
96
,
7686
(
2004
).
24.
Z.
Gao
,
M. M. R.
Hussain
,
D.
De Ceglia
,
M. A.
Vincenti
,
A.
Sarangan
,
I.
Agha
,
M.
Scalora
,
J. W.
Haus
, and
P.
Banerjee
,
Appl. Phys. Lett.
111
,
161601
(
2017
).
25.
P. E.
Hopkins
,
P. M.
Norris
,
R. J.
Stevens
,
T. E.
Beechem
, and
S.
Graham
,
J. Heat Trans.
130
,
062402
(
2008
).
26.
A.
Giri
and
P. E.
Hopkins
,
Adv. Funct. Mater.
30
,
1903857
(
2020
).
27.
E.
Swartz
and
R.
Pohl
,
Appl. Phys. Lett.
51
,
2200
(
1987
).
28.
D.
Cristea
,
L.
Cunha
,
C.
Gabor
,
I.
Ghiuta
,
C.
Croitoru
,
A.
Marin
,
L.
Velicu
,
A.
Besleaga
, and
B.
Vasile
,
Nanomaterials
9
,
476
(
2019
).
29.
J. R.
Vig
,
J. Vac. Sci. Technol. A
3
,
1027
(
1985
).
30.
J.
Hrbek
,
D. G.
van Campen
, and
I. J.
Malik
,
J. Vac. Sci. Technol. A
13
,
1409
(
1995
).
31.
Y.
Li
,
Q.
Zhang
,
N.
Zhang
,
L.
Zhu
,
J.
Zheng
, and
B. H.
Chen
,
Int. J. Hydrogen Energy
38
,
13360
(
2013
).
32.
J. V.
Rojas
,
M.
Toro-Gonzalez
,
M. C.
Molina-Higgins
, and
C. E.
Castano
,
Mater. Sci. Eng. B
205
,
28
(
2016
).
33.
See the supplementary material for the spectroscopic ellipsometry model for Ru on TaN and experimental and modeling details on time domain thermoreflectance (TDTR) and steady-state thermoreflectance (SSTR).

Supplementary Material

You do not currently have access to this content.