Low-pressure plasmas, in particular magnetron sputtering discharges, are increasingly used for the deposition of wideband gap semiconductor nitrides films (e.g., GaN or AlN) considering many benefits they exhibit with respect to conventional chemical vapor deposition techniques. Plasma-based solutions enable the dissociation of N2 molecules into N-atoms under conditions that would not be possible with the thermal process. However, as the dissociation rate remains quite small due to the strong nitrogen triple bond, it is somewhat complicated to determine and correlate the N-atoms density in the gas phase with that of the grown film in low-pressure discharges. Therefore, ns-two-photon absorption laser induced fluorescence (TALIF) has been carried out to determine the absolute density of N-atoms as a function of the pressure (tens of Pa range) in a radio-frequency sputtering plasma reactor used for GaN deposition. The TALIF set-up has been optimized using a monochromator and adequate signal processing to enhance the detection limit, enabling the measurement of N-atoms density as low as 1011 cm−3 at 15 Pa. These measurements have been completed with electron density measurements performed in the same pressure range using microwave interferometry, thus providing quantitative data on both electron and N-atom densities that can be used for fundamental understanding, process optimization, and modeling of magnetron discharge intended for nitride semiconductor deposition.

1.
Y.
Zhong
,
J.
Zhang
,
S.
Wu
,
L.
Jia
,
X.
Yang
,
Y.
Liu
,
Y.
Zhang
, and
Q.
Sun
, “
A review on the GaN-on-Si power electronic devices
,”
Fundam. Res.
2
(
3
),
462
475
(
2022
).
2.
N.
Li
,
C. P.
Ho
,
S.
Zhu
,
Y. H.
Fu
,
Y.
Zhu
, and
L. Y. T.
Lee
, “
Aluminium nitride integrated photonics: A review
,”
Nanophotonics
10
(
9
),
2347
2387
(
2021
).
3.
L.
van Deurzen
,
T.-S.
Nguyen
,
J.
Casamento
,
H. G.
Xing
, and
D.
Jena
, “
Epitaxial lattice-matched AlScN/GaN distributed Bragg reflectors
,”
Appl. Phys. Lett.
123
(
24
),
241104
(
2023
).
4.
Z.
Fan
,
Z.
Qin
,
L.
Jin
,
Z.
Yue
,
B.
Li
,
W.
Zhang
,
Y.
Wang
,
H.
Wu
, and
Z.
Sun
, “
A solar-blind vacuum-ultraviolet photodetector based on free-standing lamellar aluminum nitride single crystal
,”
Appl. Phys. Lett.
123
(
23
),
232104
(
2023
).
5.
C.
Zhang
,
M. A.
Tran
,
Z.
Zhang
,
A. E.
Dorche
,
Y.
Shen
,
B.
Shen
,
K.
Asawa
,
G.
Kim
,
N.
Kim
,
F.
Levinson
,
J. E.
Bowers
, and
T.
Komljenovic
, “
Integrated photonics beyond communications
,”
Appl. Phys. Lett.
123
(
23
),
230501
(
2023
).
6.
H.
Wei
,
J.
Wu
,
P.
Qiu
,
S.
Liu
,
Y.
He
,
M.
Peng
,
D.
Li
,
Q.
Meng
,
F.
Zaera
, and
X.
Zheng
, “
Plasma-enhanced atomic-layer-deposited gallium nitride as an electron transport layer for planar perovskite solar cells
,”
J. Mater. Chem. A
7
(
44
),
25347
25354
(
2019
).
7.
M.
Moradpour
,
P.
Ghani
, and
G.
Gatto
, “
A GaN-based battery energy storage system for residential application
,” in
International Conference on Clean Electrical Power (ICCEP)
(
IEEE
,
2019
), pp.
427
432
.
8.
T.
Polster
and
M.
Hoffmann
, “
Aluminum nitride based 3D, piezoelectric, tactile sensor
,”
Procedia Chem.
1
(
1
),
144
147
(
2009
).
9.
S. J.
Bader
,
H.
Lee
,
R.
Chaudhuri
,
S.
Huang
,
A.
Hickman
,
A.
Molnar
,
H. G.
Xing
,
D.
Jena
,
H. W.
Then
,
N.
Chowdhury
, and
T.
Palacios
, “
Prospects for wide bandgap and ultrawide bandgap CMOS devices
,”
IEEE Trans. Electron Devices
67
(
10
),
4010
4020
(
2020
).
10.
J.
Ross
and
M.
Rubin
, “
High-quality GaN grown by reactive sputtering
,”
Mater. Lett.
12
(
4
),
215
218
(
1991
).
11.
M.
Monish
,
S.
Mohan
,
D. S.
Sutar
, and
S. S.
Major
, “
Gallium nitride films of high n-type conductivity grown by reactive sputtering
,”
Semicond. Sci. Technol.
35
(
4
),
045011
(
2020
).
12.
V.
Dimitrova
,
D.
Manova
,
T.
Paskova
,
T.
Uzunov
,
N.
Ivanov
, and
D.
Dechev
, “
Aluminium nitride thin films deposited by DC reactive magnetron sputtering
,”
Vacuum
51
(
2
),
161
164
(
1998
).
13.
W.
Liu
,
W.
Xu
,
W.
Wang
,
L.
He
,
J.
Zhou
,
K.
Radhakrishnan
,
H.
Yu
, and
J.
Ren
, “
RF reactive sputtering AlN thin film at room temperature for CMOS-compatible MEMS application
,” in
Joint IEEE International Symposium on the Applications of Ferroelectric (ISAF)/International Workshop on Acoustic Transduction Materials and Devices (IWATMD)/Piezoresponse Force Microscopy (PFM)
(
IEEE
,
2017
), pp.
52
55
.
14.
A.
Prabaswara
,
J.
Birch
,
M.
Junaid
,
E. A.
Serban
,
L.
Hultman
, and
C.-L.
Hsiao
, “
Review of GaN thin film and nanorod growth using magnetron sputter epitaxy
,”
Appl. Sci.
10
(
9
),
3050
(
2020
).
15.
S.
Morikawa
,
K.
Ueno
,
A.
Kobayashi
, and
H.
Fujioka
, “
Pulsed sputtering preparation of InGaN multi-color cascaded LED stacks for large-area monolithic integration of RGB LED pixels
,”
Crystals
12
(
4
),
499
(
2022
).
16.
T.
Watanabe
,
J.
Ohta
,
T.
Kondo
,
M.
Ohashi
,
K.
Ueno
,
A.
Kobayashi
, and
H.
Fujioka
, “
AlGaN/GaN heterostructure prepared on a Si(110) substrate via pulsed sputtering
,”
Appl. Phys. Lett.
104
(
18
),
182111
(
2014
).
17.
R.
Maeda
,
K.
Ueno
,
A.
Kobayashi
, and
H.
Fujioka
, “
AlN/Al0.5Ga0.5N HEMTs with heavily Si-doped degenerate GaN contacts prepared via pulsed sputtering
,”
Appl. Phys. Express
15
(
3
),
031002
(
2022
).
18.
L.
Srinivasan
,
C.
Jadaud
,
F.
Silva
,
J.-C.
Vanel
,
J.-L.
Maurice
,
E.
Johnson
,
P.
Roca i Cabarrocas
, and
K.
Ouaras
, “
Reactive plasma sputtering deposition of polycrystalline GaN thin films on silicon substrates at room temperature
,”
J. Vac. Sci. Technol., A
41
(
5
),
053407
(
2023
).
19.
T.
Czerwiec
,
F.
Greer
, and
D. B.
Graves
, “
Nitrogen dissociation in a low pressure cylindrical ICP discharge studied by actinometry and mass spectrometry
,”
J. Phys. D
38
(
24
),
4278
(
2005
).
20.
N.
Kang
,
F.
Gaboriau
,
S.
Oh
, and
A.
Ricard
, “
Modeling and experimental study of molecular nitrogen dissociation in an Ar–N2 ICP discharge
,”
Plasma Sources Sci. Technol.
20
(
4
),
045015
(
2011
).
21.
M.
Tabbal
,
M.
Kazopoulo
,
T.
Christidis
, and
S.
Isber
, “
Enhancement of the molecular nitrogen dissociation levels by argon dilution in surface-wave-sustained plasmas
,”
Appl. Phys. Lett.
78
(
15
),
2131
2133
(
2001
).
22.
A.
Salmon
,
N. A.
Popov
,
G. D.
Stancu
, and
C. O.
Laux
, “
Quenching rate of N(2P) atoms in a nitrogen afterglow at atmospheric pressure
,”
J. Phys. D
51
(
31
),
314001
(
2018
).
23.
P.
Vašina
,
V.
Kudrle
,
A.
Tálský
,
P.
Botoš
,
M.
Mrázková
, and
M.
Meško
, “
Simultaneous measurement of N and O densities in plasma afterglow by means of NO titration
,”
Plasma Sources Sci. Technol.
13
(
4
),
668
(
2004
).
24.
A.
Remigy
,
S.
Kasri
,
T.
Darny
,
H.
Kabbara
,
L.
William
,
G.
Bauville
,
K.
Gazeli
,
S.
Pasquiers
,
J. S.
Sousa
,
N. D.
Oliveira
,
N.
Sadeghi
,
G.
Lombardi
, and
C.
Lazzaroni
, “
Cross-comparison of diagnostic and 0D modeling of a micro-hollow cathode discharge in the stationary regime in an Ar/N2 gas mixture
,”
J. Phys. D
55
(
10
),
105202
(
2021
).
25.
S. F.
Adams
and
T. A.
Miller
, “
Two-photon absorption laser-induced fluorescence of atomic nitrogen by an alternative excitation scheme
,”
Chem. Phys. Lett.
295
(
4
),
305
311
(
1998
).
26.
T. L.
Chng
,
N. D.
Lepikhin
,
I. S.
Orel
,
N. A.
Popov
, and
S. M.
Starikovskaia
, “
TALIF measurements of atomic nitrogen in the afterglow of a nanosecond capillary discharge
,”
Plasma Sources Sci. Technol.
29
(
3
),
035017
(
2020
).
27.
T.
Kimura
and
H.
Kasugai
, “
Experiments and global model of inductively coupled rf Ar/N2 discharges
,”
J. Appl. Phys.
108
(
3
),
033305
(
2010
).
28.
A.
Remigy
,
X.
Aubert
,
S.
Prasanna
,
K.
Gazeli
,
L.
Invernizzi
,
G.
Lombardi
, and
C.
Lazzaroni
, “
Absolute N-atom density measurement in an Ar/N2 micro-hollow cathode discharge jet by means of ns-two-photon absorption laser-induced fluorescence
,”
Phys. Plasmas
29
(
11
),
113508
(
2022
).
29.
K.
Ouaras
,
G.
Lombardi
,
L.
Couëdel
,
C.
Arnas
, and
K.
Hassouni
, “
Microarcing-enhanced tungsten nano and micro-particles formation in low pressure high-density plasma
,”
Phys. Plasmas
26
(
2
),
023705
(
2019
).
30.
E.
Bisceglia
,
S.
Prasanna
,
K.
Gazeli
,
X.
Aubert
,
C. Y.
Duluard
,
G.
Lombardi
, and
K.
Hassouni
, “
Investigation of N(4S) kinetics during the transients of a strongly emissive pulsed ECR plasma using ns-TALIF
,”
Plasma Sources Sci. Technol.
30
(
9
),
095001
(
2021
).
31.
K.
Gazeli
,
X.
Aubert
,
S.
Prasanna
,
C. Y.
Duluard
,
G.
Lombardi
, and
K.
Hassouni
, “
Picosecond two-photon absorption laser-induced fluorescence (ps-TALIF) in krypton: The role of photoionization on the density depletion of the fluorescing state Kr 5p′[3/2]2
,”
Phys. Plasmas
28
(
4
),
043301
(
2021
).
32.
K.
Niemi
,
V.
Schulz-von der Gathen
, and
H. F.
Döbele
, “
Absolute calibration of atomic density measurements by laser-induced fluorescence spectroscopy with two-photon excitation
,”
J. Phys. D
34
(
15
),
2330
(
2001
).
33.
J. B.
Schmidt
,
S.
Roy
,
W. D.
Kulatilaka
,
I.
Shkurenkov
,
I. V.
Adamovich
,
W. R.
Lempert
, and
J. R.
Gord
, “
Femtosecond, two-photon-absorption, laser-induced-fluorescence (fs-TALIF) imaging of atomic hydrogen and oxygen in non-equilibrium plasmas
,”
J. Phys. D
50
(
1
),
015204
(
2016
).
34.
M. G. H.
Boogaarts
,
S.
Mazouffre
,
G. J.
Brinkman
,
H. W. P.
van der Heijden
,
P.
Vankan
,
J. A. M.
van der Mullen
,
D. C.
Schram
, and
H. F.
Döbele
, “
Quantitative two-photon laser-induced fluorescence measurements of atomic hydrogen densities, temperatures, and velocities in an expanding thermal plasma
,”
Rev. Sci. Instrum.
73
(
1
),
73
86
(
2002
).
35.
G. D.
Stancu
, “
Two-photon absorption laser induced fluorescence: Rate and density-matrix regimes for plasma diagnostics
,”
Plasma Sources Sci. Technol.
29
(
5
),
054001
(
2020
).
36.
L.
Invernizzi
,
C. Y.
Duluard
,
H.
Höft
,
K.
Hassouni
,
G.
Lombardi
,
K.
Gazeli
, and
S.
Prasanna
, “
Peculiarities of measuring fluorescence decay times by a streak camera for ps-TALIF experiments in reactive plasmas
,”
Meas. Sci. Technol.
34
(
9
),
095203
(
2023
).
37.
K.
Gazeli
,
G.
Lombardi
,
X.
Aubert
,
C. Y.
Duluard
,
S.
Prasanna
, and
K.
Hassouni
, “
Progresses on the use of two-photon absorption laser induced fluorescence (TALIF) diagnostics for measuring absolute atomic densities in plasmas and flames
,”
Plasma
4
(
1
),
145
171
(
2021
).
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