Atomic layer deposition (ALD) of aluminum nitride (AlN) using in situ atomic layer annealing (ALA) is studied for microelectromechanical systems (MEMS). Effective piezoelectric in-plane actuation and sensing requires deposition of high crystal quality and (0002) oriented AlN on vertical sidewalls of MEMS structures. Previous studies have shown that the crystal quality of ALD AlN can be significantly improved using ALA but have not studied the conformal coverage or crystal quality on metal electrodes, which are required for piezoelectric MEMS devices. In this study, AlN thin films are deposited on Si, Al, Pt, and on vertical sidewalls etched into Si. The AlN microstructure and properties are studied using x-ray diffraction methods, transmission electron microscopy, and Fourier transform infrared spectroscopy. The conformal coverage is evaluated by measuring the film thickness on the vertical sidewalls. The effects of postdeposition annealing are studied as well. This study aims to enable effective piezoelectric actuation and sensing for MEMS sensors. The conformal coverage of the ALA ALD process is excellent and AlN has the best crystal quality and degree of orientation when deposited on Al. The as-deposited films contain oxygen impurities, which might be detrimental to the piezoelectric properties of AlN. Annealing at high temperatures reduced the number of impurities but did not improve the crystal quality.

1.
G.
Wingqvist
,
Surf. Coat. Technol.
205
,
1279
(
2010
), iCMCTF 2010 Special Issue.
2.
T. Y.
Lee
and
J. T.
Song
,
Thin Solid Films
518
,
6630
(
2010
).
3.
M. D.
Williams
,
B. A.
Griffin
,
T. N.
Reagan
,
J. R.
Underbrink
, and
M.
Sheplak
,
J. Microelectromech. Syst
21
,
270
(
2012
).
4.
S.
Akhbari
,
F.
Sammoura
,
S.
Shelton
,
C.
Yang
,
D.
Horsley
, and
L.
Lin
, “Highly responsive curved aluminum nitride pMUT,” in Proceedings of IEEE 27th International Conference on Micro Electro Mechanical Systems (MEMS) (IEEE, San Francisco, 2014), pp. 124–127.
5.
D.
Gong
,
H.
Cai
,
Y.
Xia
,
S.
Ma
,
H.
Liu
,
Y.
Chiu
, and
Y.
Jin
, “Fabrication and characterization of AlN based piezoelectric micromachined ultrasonic transducer for contact sensing,” in Proceedings of 19th International Conference on Electronic Packaging Technology (ICEPT) (IEEE, Shanghai, 2018), pp. 1442–1447.
6.
S.
Trolier-McKinstry
and
P.
Muralt
,
J. Electroceram.
12
,
7
(
2004
).
7.
M.-A.
Dubois
and
P.
Muralt
,
Sens. Actuators, A
77
,
106
(
1999
).
8.
E.
Österlund
,
J.
Kinnunen
,
V.
Rontu
,
A.
Torkkeli
, and
M.
Paulasto-Kröckel
,
J. Alloys Compd.
772
,
306
(
2019
).
9.
D.
Zhuang
and
J.
Edgar
,
Mater. Sci. Eng. R Rep.
48
,
1
(
2005
).
10.
M.
Ramezani
,
V.
Felmetsger
,
N.
Rudawski
, and
R.
Tabrizian
,
IEEE Trans. Ultrason., Ferroelectr., Freq. Control
68
,
753
759
(2020).
11.
H.
Cui
,
R.
Hensleigh
,
D.
Yao
,
D.
Maurya
,
P.
Kumar
,
M. G.
Kang
,
S.
Priya
, and
X. R.
Zheng
,
Nat. Mater.
18
,
234
(
2019
).
12.
A.
Yanguas-Gil
,
Y.
Yang
,
N.
Kumar
, and
J. R.
Abelson
,
J. Vac. Sci. Technol. A
27
,
1235
(
2009
).
13.
E.
Österlund
,
S.
Suihkonen
,
G.
Ross
,
A.
Torkkeli
,
H.
Kuisma
, and
M.
Paulasto-Kröckel
,
J. Cryst. Growth
531
,
125345
(
2020
).
14.
N.
Nepal
,
S.
Qadri
,
J.
Hite
,
N.
Mahadik
,
M.
Mastro
, and
C.
Eddy
, Jr.
,
Appl. Phys. Lett.
103
,
082110
(
2013
).
15.
M.
Broas
,
P.
Sippola
,
T.
Sajavaara
,
V.
Vuorinen
,
A.
Pyymaki Perros
,
H.
Lipsanen
, and
M.
Paulasto-Kröckel
,
J. Vac. Sci. Technol. A
34
,
041506
(
2016
).
16.
T.
Nguyen
,
N.
Adjeroud
,
S.
Glinsek
,
Y.
Fleming
,
J.
Guillot
,
P.
Grysan
, and
J.
Polesel-Maris
,
APL Mater.
8
,
071101
(
2020
).
17.
H.-Y.
Shih
,
W.-H.
Lee
,
W.-C.
Kao
,
Y.-C.
Chuang
,
R.-M.
Lin
,
H.-C.
Lin
,
M.
Shiojiri
, and
M.-J.
Chen
,
Sci. Rep.
7
,
1
(
2017
).
18.
H.
Seppänen
,
I.
Kim
,
J.
Etula
,
E.
Ubyivovk
,
A.
Bouravleuv
, and
H.
Lipsanen
,
Materials
12
,
406
(
2019
).
19.
M.
Bosund
,
T.
Sajavaara
,
M.
Laitinen
,
T.
Huhtio
,
M.
Putkonen
,
V.-M.
Airaksinen
, and
H.
Lipsanen
,
Appl. Surf. Sci.
257
,
7827
(
2011
).
20.
S.
Kobayashi
,
Rigaku J.
26
(
1
),
3
11
(
2010
).
21.
A.
Mazzalai
,
D.
Balma
,
N.
Chidambaram
,
L.
Jin
, and
P.
Muralt
, “Simultaneous piezoelectric and ferroelectric characterization of thin films for MEMS actuators,” in Proceedings of 2013 Joint IEEE International Symposium on Applications of Ferroelectric and Workshop on Piezoresponse Force Microscopy (IEEE, Prague, 2013), pp. 363–366.
22.
J.
Borges
,
F.
Vaz
, and
L.
Marques
,
Appl. Surf. Sci.
257
,
1478
(
2010
).
23.
Z.-Y.
Wang
, et al.,
Nanoscale Res. Lett.
10
,
46
(
2015
).
24.
A.
Artieda
,
M.
Barbieri
,
C. S.
Sandu
, and
P.
Muralt
,
J. Appl. Phys.
105
,
024504
(
2009
).
25.
W.
Wang
,
W.
Yang
,
Z.
Liu
,
Y.
Lin
,
S.
Zhou
,
H.
Qian
,
F.
Gao
, and
G.
Li
,
CrystEngComm
16
,
4100
(
2014
).
26.
C.
Sun
,
P.
Kung
,
A.
Saxler
,
H.
Ohsato
,
K.
Haritos
, and
M.
Razeghi
,
J. Appl. Phys.
75
,
3964
(
1994
).
27.
H.
Loebl
,
C.
Metzmacher
,
R.
Milsom
,
P.
Lok
,
F.
Van Straten
, and
A.
Tuinhout
,
J. Electroceram.
12
,
109
(
2004
).
28.
S.-H.
Lee
,
J.-K.
Lee
, and
K. H.
Yoon
,
J. Vac. Sci. Technol., A
21
,
1
(
2003
).
29.
R. S.
Naik
, et al.,
IEEE Trans. Ultrason., Ferroelectr., Freq. Control
47
,
292
(
2000
).
30.
J.
Bjurström
,
D.
Rosén
,
I.
Katardjiev
,
V. M.
Yanchev
, and
I.
Petrov
,
IEEE Trans. Ultrason., Ferroelectr., Freq. Control
51
,
1347
(
2004
).
31.
F.
Martin
,
P.
Muralt
,
M.-A.
Dubois
, and
A.
Pezous
,
J. Vac. Sci. Technol., A
22
,
361
(
2004
).
32.
K.
Tonisch
,
V.
Cimalla
,
C.
Foerster
,
D.
Dontsov
, and
O.
Ambacher
,
Phys. Status Solidi C
3
,
2274
(
2006
).
33.
H.
Demiryont
,
L.
Thompson
, and
G.
Collins
,
J. Appl. Phys.
59
,
3235
(
1986
).
34.
M. L.
Panchula
and
J. Y.
Ying
,
J. Am. Ceram. Soc.
86
,
1114
(
2003
).
35.
J.
Coates
, “Interpretation of infrared spectra, a practical approach,” in Encyclopedia of Analytical Chemistry: Applications, Theory and Instrumentation (John Wiley & Sons, Hoboken, 2006).
36.
A. P.
Perros
,
H.
Hakola
,
T.
Sajavaara
,
T.
Huhtio
, and
H.
Lipsanen
,
J. Phys. D: Appl. Phys.
46
,
505502
(
2013
).
37.
U.
Mazur
and
A. C.
Cleary
,
J. Phys. Chem.
94
,
189
(
1990
).
38.
X. D.
Wang
,
K.
Hipps
, and
U.
Mazur
,
Langmuir
8
,
1347
(
1992
).
39.
D. N.
Goldstein
,
J. A.
McCormick
, and
S. M.
George
,
J. Phys. Chem. C
112
,
19530
(
2008
).
40.
R.
Dalmau
,
R.
Collazo
,
S.
Mita
, and
Z.
Sitar
,
J. Electron. Mater.
36
,
414
(
2007
).
41.
A.
Perros
,
M.
Bosund
,
T.
Sajavaara
,
M.
Laitinen
,
L.
Sainiemi
,
T.
Huhtio
, and
H.
Lipsanen
,
J. Vac. Sci. Technol., A
30
,
011504
(
2012
).
42.
P.
Sippola
, et al.,
J. Vac. Sci. Technol., A
36
,
051508
(
2018
).
43.
J.
Edgar
,
C.
Carosella
,
C.
Eddy
, and
D.
Smith
,
J. Mater. Sci.: Mater. Electron.
7
,
247
(
1996
).
44.
A.
Sanz-Hervás
,
E.
Iborra
,
M.
Clement
,
J.
Sangrador
, and
M.
Aguilar
,
Diamond Relat. Mater.
12
,
1186
(
2003
).
45.
M.
Moram
and
M.
Vickers
,
Rep. Prog. Phys.
72
,
036502
(
2009
).
46.
D.
Nilsson
,
E.
Janzén
, and
A.
Kakanakova-Georgieva
,
J. Phys. D: Appl. Phys.
49
,
175108
(
2016
).
47.
A.
Wright
,
J. Appl. Phys.
82
,
2833
(
1997
).
48.
M.
Signore
,
A.
Taurino
,
D.
Valerini
,
A.
Rizzo
,
I.
Farella
,
M.
Catalano
,
F.
Quaranta
, and
P.
Siciliano
,
J. Alloys Compd.
649
,
1267
(
2015
).
49.
S.
Raghavan
and
J. M.
Redwing
,
J. Cryst. Growth
261
,
294
(
2004
).
50.
L.
Vergara
,
J.
Olivares
,
E.
Iborra
,
M.
Clement
,
A.
Sanz-Hervás
, and
J.
Sangrador
,
Thin Solid Films
515
,
1814
(
2006
).
51.
L.
Vergara
,
M.
Clement
,
E.
Iborra
,
A.
Sanz-Hervás
,
J. G.
López
,
Y.
Morilla
,
J.
Sangrador
, and
M.
Respaldiza
,
Diamond Relat. Mater.
13
,
839
(
2004
).
52.
V.
Brien
and
P.
Pigeat
,
J. Cryst. Growth
310
,
3890
(
2008
).
53.
P.
Bogusławski
and
J.
Bernholc
,
Phys. Rev. B
56
,
9496
(
1997
).
54.
See supplementary material at https://doi.org/10.1116/6.0000724 for AFM and XRD results.

Supplementary Material

You do not currently have access to this content.