The carbon vacancy (VC) is a major point defect in high-purity 4H-SiC epitaxial layers limiting the minority charge carrier lifetime. In layers grown by chemical vapor deposition techniques, the VC concentration is typically in the range of 1012 cm−3, and after device processing at temperatures approaching 2000 °C, it can be enhanced by several orders of magnitude. In the present study, both as-grown layers and a high-temperature processed one have been annealed at 1500 °C and the VC concentration is demonstrated to be strongly reduced, exhibiting a value of only a few times 1011 cm−3 as determined by deep-level transient spectroscopy measurements. The value is reached already after annealing times on the order of 1 h and is evidenced to reflect thermodynamic equilibrium under C-rich ambient conditions. The physical processes controlling the kinetics for establishment of the VC equilibrium are estimated to have an activation energy below ∼3 eV and both in-diffusion of carbon interstitials and out-diffusion of VC's are discussed as candidates. This concept of VC elimination is flexible and readily integrated in a materials and device processing sequence.

1.
N.
Kaji
,
H.
Niwa
,
J.
Suda
, and
T.
Kimoto
,
Mater. Sci. Forum
778–780
,
832
(
2014
).
2.
N. T.
Son
,
X. T.
Trinh
,
L. S.
Løvlie
,
B. G.
Svensson
,
K.
Kawahara
,
J.
Suda
,
T.
Kimoto
,
T.
Umeda
,
J.
Isoya
,
T.
Makino
,
T.
Ohshima
, and
E.
Janzén
,
Phys. Rev. Lett.
109
,
187603
(
2012
).
3.
P. B.
Klein
,
B. V.
Shanabrook
,
S. W.
Huh
,
A. Y.
Polyakov
,
M.
Skowronski
,
J. J.
Sumakeris
, and
M. J.
O'Loughlin
,
Appl. Phys. Lett.
88
,
052110
(
2006
).
4.
K.
Danno
,
D.
Nakamura
, and
T.
Kimoto
,
Appl. Phys. Lett.
90
,
202109
(
2007
).
5.
P. B.
Klein
,
J. Appl. Phys.
103
,
033702
(
2008
).
6.
T.
Hiyoshi
and
T.
Kimoto
,
Appl. Phys. Express
2
,
041101
(
2009
).
7.
T.
Hiyoshi
and
T.
Kimoto
,
Appl. Phys. Express
2
,
091101
(
2009
).
8.
L. S.
Løvlie
and
B. G.
Svensson
,
Appl. Phys. Lett.
98
,
052108
(
2011
).
9.
L. S.
Løvlie
and
B. G.
Svensson
,
Phys. Rev. B
86
,
075205
(
2012
).
10.
K.
Kawahara
,
J.
Suda
, and
T.
Kimoto
,
J. Appl. Phys.
111
,
053710
(
2012
).
11.
L.
Storasta
and
H.
Tsuchida
,
Appl. Phys. Lett.
90
,
062116
(
2007
).
12.
L.
Storasta
,
H.
Tsuchida
,
T.
Miyazawa
, and
T.
Ohshima
,
J. Appl. Phys.
103
,
013705
(
2008
).
13.
R.
Nipoti
,
A.
Nath
,
M. V.
Rao
,
A.
Hallén
,
A.
Carnera
, and
Y.-L.
Tian
,
Appl. Phys. Express
4
,
111301
(
2011
).
14.
H. M.
Ayedh
,
V.
Bobal
,
R.
Nipoti
,
A.
Hallén
, and
B. G.
Svensson
,
J. Appl. Phys.
115
,
012005
(
2014
).
15.
H. M.
Ayedh
,
R.
Nipoti
,
A.
Hallén
, and
B. G.
Svensson
,
Mater. Sci. Forum
821–823
,
351
(
2015
).
16.
T.
Hornos
,
A.
Gali
, and
B. G.
Svensson
,
Mater. Sci. Forum
679–680
,
261
(
2011
).
17.
X. T.
Trinh
,
K.
Szász
,
T.
Hornos
,
K.
Kawahara
,
J.
Suda
,
T.
Kimoto
,
A.
Gali
,
E.
Janzén
, and
N. T.
Son
,
Phys. Rev. B
88
,
235209
(
2013
).
18.
R.
Nipoti
,
F.
Mancarella
,
F.
Moscatelli
,
R.
Rizzoli
,
S.
Zampolli
, and
M.
Ferri
,
Electrochem. Solid-State Lett.
13
,
H432
(
2010
).
19.
B. G.
Svensson
,
K.-H.
Rydén
, and
B. M. S.
Lewerentz
,
J. Appl. Phys.
66
,
1699
(
1989
).
20.
M.
Bockstedte
,
A.
Mattausch
, and
O.
Pankratov
,
Phys. Rev. B
68
,
205201
(
2003
).
21.
R.
Nipoti
,
R.
Scaburri
,
A.
Hallén
, and
A.
Parisini
,
J. Mater. Res.
28
,
17
(
2013
).
22.
H. M.
Ayedh
,
A.
Hallén
, and
B. G.
Svensson
,
J. Appl. Phys.
118
,
175701
(
2015
).
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