Near-ideal behavior in Schottky contacts to Si-doped AlN was observed as evidenced by a low ideality factor of 1.5 at room temperature. A temperature-independent Schottky barrier height of 1.9 eV was extracted from temperature-dependent I–V measurements. An activation energy of ∼300 meV was observed in the series resistance, which corresponded to the ionization energy of the deep Si donor state. Both Ohmic and Schottky contacts were stable up to 650 °C, with around four orders of magnitude rectification at this elevated temperature. These results demonstrate the potential of AlN as a platform for power devices capable of operating in extreme environments.

1.
J. Y.
Tsao
,
S.
Chowdhury
,
M. A.
Hollis
,
D.
Jena
,
N. M.
Johnson
,
K. A.
Jones
,
R. J.
Kaplar
,
S.
Rajan
,
C. G.
Van de Walle
,
E.
Bellotti
,
C. L.
Chua
,
R.
Collazo
,
M. E.
Coltrin
,
J. A.
Cooper
,
K. R.
Evans
,
S.
Graham
,
T. A.
Grotjohn
,
E. R.
Heller
,
M.
Higashiwaki
,
M. S.
Islam
,
P. W.
Juodawlkis
,
M. A.
Khan
,
A. D.
Koehler
,
J. H.
Leach
,
U. K.
Mishra
,
R. J.
Nemanich
,
R. C. N.
Pilawa‐Podgurski
,
J. B.
Shealy
,
Z.
Sitar
,
M. J.
Tadjer
,
A. F.
Witulski
,
M.
Wraback
, and
J. A.
Simmons
, “
Ultrawide‐bandgap semiconductors: Research opportunities and challenges
,”
Adv. Electron. Mater.
4
(
1
),
1600501
(
2018
).
2.
H.
Amano
,
R.
Collazo
,
C. D.
Santi
,
S.
Einfeldt
,
M.
Funato
,
J.
Glaab
,
S.
Hagedorn
,
A.
Hirano
,
H.
Hirayama
,
R.
Ishii
,
Y.
Kashima
,
Y.
Kawakami
,
R.
Kirste
,
M.
Kneissl
,
R.
Martin
,
F.
Mehnke
,
M.
Meneghini
,
A.
Ougazzaden
,
P. J.
Parbrook
,
S.
Rajan
,
P.
Reddy
,
F.
Römer
,
J.
Ruschel
,
B.
Sarkar
,
F.
Scholz
,
L. J.
Schowalter
,
P.
Shields
,
Z.
Sitar
,
L.
Sulmoni
,
T.
Wang
,
T.
Wernicke
,
M.
Weyers
,
B.
Witzigmann
,
Y.-R.
Wu
,
T.
Wunderer
, and
Y.
Zhang
, “
The 2020 UV emitter roadmap
,”
J. Phys. D: Appl. Phys.
53
(
50
),
503001
(
2020
).
3.
A. G.
Baca
,
A. M.
Armstrong
,
B. A.
Klein
,
A. A.
Allerman
,
E. A.
Douglas
, and
R. J.
Kaplar
, “
Al-rich AlGaN based transistors
,”
J. Vac. Sci. Technol. A
38
(
2
),
020803
(
2020
).
4.
R.
Rounds
,
B.
Sarkar
,
D.
Alden
,
Q.
Guo
,
A.
Klump
,
C.
Hartmann
,
T.
Nagashima
,
R.
Kirste
,
A.
Franke
,
M.
Bickermann
,
Y.
Kumagai
,
Z.
Sitar
, and
R.
Collazo
, “
The influence of point defects on the thermal conductivity of AlN crystals
,”
J. Appl. Phys.
123
(
18
),
185107
(
2018
).
5.
K. A.
Jones
,
T. P.
Chow
,
M.
Wraback
,
M.
Shatalov
,
Z.
Sitar
,
F.
Shahedipour
,
K.
Udwary
, and
G. S.
Tompa
, “
AlGaN devices and growth of device structures
,”
J. Mater. Sci.
50
(
9
),
3267
3307
(
2015
).
6.
Y.
Irokawa
,
E. A. G.
Víllora
, and
K.
Shimamura
, “
Shottky barrier diodes on AlN free-standing substrates
,”
Jpn. J. Appl. Phys.
51
(
4R
),
040206
(
2012
).
7.
T.
Kinoshita
,
T.
Nagashima
,
T.
Obata
,
S.
Takashima
,
R.
Yamamoto
,
R.
Togashi
,
Y.
Kumagai
,
R.
Schlesser
,
R.
Collazo
,
A.
Koukitu
, and
Z.
Sitar
, “
Fabrication of vertical Schottky barrier diodes on n-type freestanding AlN substrates grown by hydride vapor phase epitaxy
,”
Appl. Phys. Express
8
(
6
),
061003
(
2015
).
8.
T.
Maeda
,
R.
Page
,
K.
Nomoto
,
M.
Toita
,
H. G.
Xing
, and
D.
Jena
, “
AlN quasi-vertical Schottky barrier diode on AlN bulk substrate using Al0.9Ga0.1N current spreading layer
,”
Appl. Phys. Express
15
(
6
),
061007
(
2022
).
9.
H.
Fu
,
I.
Baranowski
,
X.
Huang
,
H.
Chen
,
Z.
Lu
,
J.
Montes
,
X.
Zhang
, and
Y.
Zhao
, “
Demonstration of AlN Schottky barrier diodes with blocking voltage over 1 kV
,”
IEEE Electron Device Lett.
38
(
9
),
1286
1289
(
2017
).
10.
H.
Okumura
,
Y.
Watanabe
, and
T.
Shibata
, “
Temperature dependence of electrical characteristics of Si-implanted AlN layers on sapphire substrates
,”
Appl. Phys. Express
16
(
6
),
064005
(
2023
).
11.
P.
Reddy
,
I.
Bryan
,
Z.
Bryan
,
J.
Tweedie
,
R.
Kirste
,
R.
Collazo
, and
Z.
Sitar
, “
Schottky contact formation on polar and non-polar AlN
,”
J. Appl. Phys.
116
(
19
),
194503
(
2014
).
12.
P.
Reddy
,
I.
Bryan
,
Z.
Bryan
,
W.
Guo
,
L.
Hussey
,
R.
Collazo
, and
Z.
Sitar
, “
The effect of polarity and surface states on the Fermi level at III-nitride surfaces
,”
J. Appl. Phys.
116
(
12
),
123701
(
2014
).
13.
P.
Reddy
,
I.
Bryan
,
Z.
Bryan
,
J.
Tweedie
,
S.
Washiyama
,
R.
Kirste
,
S.
Mita
,
R.
Collazo
, and
Z.
Sitar
, “
Charge neutrality levels, barrier heights, and band offsets at polar AlGaN
,”
Appl. Phys. Lett.
107
(
9
),
091603
(
2015
).
14.
R.
Schlesser
,
V.
Noveski
, and
Z.
Sitar
, US7678195B2 (16 March
2010
).
15.
D.
Ehrentraut
and
Z.
Sitar
, “
Advances in bulk crystal growth of AlN and GaN
,”
MRS Bull.
34
(
4
),
259
265
(
2009
).
16.
R.
Schlesser
,
R.
Dalmau
, and
Z.
Sitar
, “
Seeded growth of AlN bulk single crystals by sublimation
,”
J. Cryst. Growth
241
(
4
),
416
420
(
2002
).
17.
V.
Noveski
,
R.
Schlesser
,
B.
Raghothamachar
,
M.
Dudley
,
S.
Mahajan
,
S.
Beaudoin
, and
Z.
Sitar
, “
Seeded growth of bulk AlN crystals and grain evolution in polycrystalline AlN boules
,”
J. Cryst. Growth
279
(
1
),
13
19
(
2005
).
18.
I.
Bryan
,
Z.
Bryan
,
S.
Mita
,
A.
Rice
,
J.
Tweedie
,
R.
Collazo
, and
Z.
Sitar
, “
Surface kinetics in AlN growth: A universal model for the control of surface morphology in III-nitrides
,”
J. Cryst. Growth
438
,
81
89
(
2016
).
19.
A.
Rice
,
R.
Collazo
,
J.
Tweedie
,
R.
Dalmau
,
S.
Mita
,
J.
Xie
, and
Z.
Sitar
, “
Surface preparation and homoepitaxial deposition of AlN on (0001)-oriented AlN substrates by metalorganic chemical vapor deposition
,”
J. Appl. Phys.
108
(
4
),
043510
(
2010
).
20.
P.
Reddy
,
M. P.
Hoffmann
,
F.
Kaess
,
Z.
Bryan
,
I.
Bryan
,
M.
Bobea
,
A.
Klump
,
J.
Tweedie
,
R.
Kirste
,
S.
Mita
,
M.
Gerhold
,
R.
Collazo
, and
Z.
Sitar
, “
Point defect reduction in wide bandgap semiconductors by defect quasi Fermi level control
,”
J. Appl. Phys.
120
(
18
),
185704
(
2016
).
21.
P.
Reddy
,
S.
Washiyama
,
F.
Kaess
,
R.
Kirste
,
S.
Mita
,
R.
Collazo
, and
Z.
Sitar
, “
Point defect reduction in MOCVD (Al)GaN by chemical potential control and a comprehensive model of C incorporation in GaN
,”
J. Appl. Phys.
122
(
24
),
245702
(
2017
).
22.
S.
Washiyama
,
P.
Reddy
,
B.
Sarkar
,
M. H.
Breckenridge
,
Q.
Guo
,
P.
Bagheri
,
A.
Klump
,
R.
Kirste
,
J.
Tweedie
,
S.
Mita
,
Z.
Sitar
, and
R.
Collazo
, “
The role of chemical potential in compensation control in Si:AlGaN
,”
J. Appl. Phys.
127
(
10
),
105702
(
2020
).
23.
P.
Bagheri
,
C.
Quiñones-Garcia
,
D.
Khachariya
,
S.
Rathkanthiwar
,
P.
Reddy
,
R.
Kirste
,
S.
Mita
,
J.
Tweedie
,
R.
Collazo
, and
Z.
Sitar
, “
High electron mobility in AlN:Si by point and extended defect management
,”
J. Appl. Phys.
132
(
18
),
185703
(
2022
).
24.
M. H.
Breckenridge
,
P.
Bagheri
,
Q.
Guo
,
B.
Sarkar
,
D.
Khachariya
,
S.
Pavlidis
,
J.
Tweedie
,
R.
Kirste
,
S.
Mita
,
P.
Reddy
,
R.
Collazo
, and
Z.
Sitar
, “
High n-type conductivity and carrier concentration in Si-implanted homoepitaxial AlN
,”
Appl. Phys. Lett.
118
(
11
),
112104
(
2021
).
25.
H.
Ahmad
,
Z.
Engel
,
C. M.
Matthews
,
S.
Lee
, and
W. A.
Doolittle
, “
Realization of homojunction PN AlN diodes
,”
J. Appl. Phys.
131
(
17
),
175701
(
2022
).
26.
H.
Ahmad
,
Z.
Engel
,
C. M.
Matthews
, and
W. A.
Doolittle
, “
p-type AlN based heteroepitaxial diodes with Schottky, pin, and junction barrier Schottky character achieving significant breakdown performance
,”
J. Appl. Phys.
130
(
19
),
195702
(
2021
).
27.
R.
Dalmau
,
B.
Moody
,
R.
Schlesser
,
S.
Mita
,
J.
Xie
,
M.
Feneberg
,
B.
Neuschl
,
K.
Thonke
,
R.
Collazo
,
A.
Rice
,
J.
Tweedie
, and
Z.
Sitar
, “
Growth and characterization of AlN and AlGaN epitaxial films on AlN single crystal substrates
,”
J. Electrochem. Soc.
158
(
5
),
H530
(
2011
).
28.
P.
Bagheri
,
P.
Reddy
,
S.
Mita
,
D.
Szymanski
,
J. H.
Kim
,
Y.
Guan
,
D.
Khachariya
,
A.
Klump
,
S.
Pavlidis
,
R.
Kirste
,
R.
Collazo
, and
Z.
Sitar
, “
On the Ge shallow-to-deep level transition in Al-rich AlGaN
,”
J. Appl. Phys.
130
(
5
),
055702
(
2021
).
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