CuxAl1−x thin films with 0.2 ≤ x ≤ 0.7 have been studied as potential alternatives for metallization of advanced interconnects. First-principles simulations were used to obtain the CuxAl1−x electronic structure and cohesive energy to benchmark different intermetallics and their prospects for interconnect metallization. Next, thin CuxAl1−x films were deposited by PVD with thicknesses in the range between 3 and 28 nm. The lowest resistivities of 9.5 μΩ cm were obtained for 28 nm thick stoichiometric CuAl and CuAl2 after 400 °C postdeposition annealing. Based on the experimental results, we discuss the main challenges for the studied aluminides from an interconnect point of view, namely, control of the film stoichiometry, the phase separation observed for off-stoichiometric CuAl and CuAl2, as well as the presence of a nonstoichiometric surface oxide.

1.
P.
Kapur
,
J. P.
McVittie
, and
K. C.
Saraswat
,
IEEE Trans. Electron Devices
49
,
590
(
2002
).
2.
D.
Josell
,
S. H.
Brongersma
, and
Z.
Tőkei
,
Annu. Rev. Mater. Res.
39
,
231
(
2009
).
3.
A. S.
Oates
,
ECS J. Solid State Sci.
4
,
N3168
(
2015
).
4.
Z.
Tőkei
et al.,
2020 IEEE International Electron Devices Meeting
, San Francisco, CA,
2020
, p.
32.2.1
(unpublished).
5.
D.
Gall
,
2020 International Symposium on VLSI Technology, Systems and Applications
, Hsinchu, Taiwan,
2020
, p.
112
(unpublished).
6.
C.
Adelmann
et al.,
2014 IEEE International Interconnect Technology Conference
, San Jose, CA,
2014
, p.
173
(unpublished).
7.
C.
Adelmann
et al.,
2018 IEEE Internatonal Interconnect Technology Conference
, Santa Clara, CA,
2018
, p.
154
(unpublished).
8.
D.
Gall
,
J. Appl. Phys.
127
,
050901
(
2020
).
9.
S.
Dutta
,
K.
Sankaran
,
K.
Moors
,
G.
Pourtois
,
S.
Van Elshocht
,
J.
Bömmels
,
W.
Vandervorst
,
Z.
Tőkei
, and
C.
Adelmann
,
J. Appl. Phys.
122
,
025107
(
2017
).
10.
D.
Wan
et al.,
2018 IEEE International Interconnect Technology Conference
, Santa Clara, CA,
2018
, p.
10
(unpublished).
11.
V.
Founta
et al,
Materialia
24
,
101511
(
2022
).
12.
O. V.
Pedreira
et al.,
2017 IEEE International Reliability Physics Symposium
, Monterey, CA, USA,
2017
, p.
6B–2.1
(unpublished).
13.
Y.
Terada
,
K.
Ohkubo
,
T.
Mohri
, and
T.
Suzuki
,
Mater. Trans.
43
,
3167
(
2002
).
14.
B.
Van Troeye
,
K.
Sankaran
,
Z.
Tokei
,
C.
Adelmann
, and
G.
Pourtois
,
Phys. Rev. B
108
,
125117
(
2023
).
15.
J.-P.
Soulié
,
Z.
Tőkei
,
J.
Swerts
and
C.
Adelmann
,
2021 IEEE International Interconnect Technology Conference
, Kyoto, Japan,
2021
, p.
1
(unpublished).
16.
L.
Chen
,
D.
Ando
,
Y.
Sutou
, and
J.
Koike
,
J. Vac. Sci. Technol. B
37
,
031215
(
2019
).
17.
T.
Kuge
,
M.
Yahagi
, and
J.
Koike
,
J. Alloys Compd.
918
,
165615
(
2022
).
18.
T.
Kuge
,
M.
Yahagi
and
J.
Koike
,
2023 IEEE International Interconnect Technology Conference
, Dresden, Germany,
2023
, p.
1
(unpublished).
19.
J. L.
Murray
,
Int. Met. Rev.
30
,
211
(
1985
).
20.
P.
Giannozzi
et al,
J. Phys.: Condens. Matter
21
,
395502
(
2009
).
21.
K. F.
Garrity
,
J. W.
Bennett
,
K. M.
Rabe
, and
D.
Vanderbilt
,
Comput. Mater. Sci.
81
,
446
(
2014
).
22.
J. P.
Perdew
,
K.
Burke
, and
M.
Ernzerhof
,
Phys. Rev. Lett.
77
,
3865
(
1996
).
23.
H. J.
Monkhorst
and
J. D.
Pack
,
Phys. Rev. B
13
,
5188
(
1976
).
24.
Anubhav
Jain
et al,
APL Mater.
1
,
011002
(
2013
).
25.
D.
Gall
,
J. Appl. Phys.
119
,
085101
(
2016
).
26.
K.
Moors
,
K.
Sankaran
,
G.
Pourtois
, and
C.
Adelmann
,
Phys. Rev. Mat.
6
,
123804
(
2022
).
27.
F. J.
Humphreys
and
M.
Hatherly
,
Recrystallization and Related Annealing Phenomena
, 2nd ed. (
Elsevier
,
Oxford
,
2004
).
28.
C.
Macchioni
,
J. A.
Rayne
, and
C. L.
Bauer
,
Phys. Rev. B
25
,
3865
(
1982
).
29.
J. J.
Gniewek
and
C. A.
Wasik
,
J. Appl. Phys.
42
,
2151
(
1971
).
30.
T.
Kuge
,
M.
Yahagi
, and
J.
Koike
,
2021 IEEE International Interconnect Technology Conference
, Kyoto, Japan,
2021
, p.
1
(unpublished).
31.
T.
Kuge
,
M.
Yahagi
, and
J.
Koike
,
2022 IEEE International Interconnect Technology Conference
, San Jose, CA,
2022
, p.
22
(unpublished).
32.
T.
Kuge
,
M.
Yahagi
, and
J.
Koike
,
IEEE Trans. Device Mater. Reliab.
24
,
14
(
2024
).
33.
K.-A.
Son
,
N.
Missert
,
J. C.
Barbour
,
J. J.
Hren
,
R. G.
Copeland
, and
K. G.
Minor
,
J. Electrochem. Soc.
148
,
B260
(
2001
).
34.
J.-P.
Soulié
,
Z.
Tőkei
,
J.
Swerts
, and
C.
Adelmann
,
2022 IEEE International. Interconnect Technology Conference
, San Jose, CA,
2022
, p.
73
.
35.
J.-P.
Soulié
et al,
Microelectron. Eng.
286
,
112141
(
2024
).
You do not currently have access to this content.