Schottky diodes fabricated on undoped n-GaN films grown by hydride vapor phase epitaxy showed more than two orders of magnitude higher reverse current if the films contained open core defects. The open core defects were revealed by scanning electron microscope observation in secondary electrons, microcathodoluminescence (MCL), and electron beam induced current (EBIC) modes. Plan-view EBIC imaging showed that such films contained a relatively high density of large (∼10 μm in diameter) dark defects that were absent in good films with low leakage current. In plan-view scanning electron microscope images, pits with the density similar to the density of dark defects were observed. Cross-sectional MCL observation showed that the pits terminated the vertical micropipes starting near the interface with the substrate. Some of the micropipes closed approximately halfway through the grown thickness. The regions of micropipes, either closed or not, showed a higher intensity of bandedge and defect MCL bands. Possible reasons for the formation of such structures are discussed.

1.
K.
Fujito
,
S.
Kubo
,
H.
Nagaoka
,
T.
Mochizuki
,
H.
Namita
, and
S.
Nagao
,
J. Cryst. Growth
311
,
3011
(
2009
).
2.
V.
Dmitriev
and
A.
Usikov
,
III-Nitride Semi-Conductor Materials
, edited by
Z. C.
Feng
(
Imperial College
,
London
,
2006
), pp.
1
40
.
3.
K.
Fujito
,
S.
Kubo
, and
I.
Fujimura
,
MRS Bull.
34
,
313
(
2009
).
4.
R.
Kroger
,
T.
Paskova
,
B.
Monemar
,
S.
Frigge
,
D.
Hommel
, and
A.
Rosenauer
,
Phys. Status Solidi C
4
,
2564
(
2007
).
5.
T.
Yoshida
,
Y.
Oshima
,
T.
Eri
,
K.
Watanabe
,
M.
Shibata
, and
T.
Mishima
,
Phys. Status Solidi A
205
,
1053
(
2008
).
6.
M. L.
Reed
,
E. D.
Readinger
,
H.
Shen
,
M.
Wraback
,
A.
Syrkin
,
A.
Usikov
,
O.
Kovalenkov
, and
V. A.
Dmitriev
,
Appl. Phys. Lett.
93
,
133505
(
2008
).
7.
A.
Usikov
,
V.
Soukhoveev
,
O.
Kovalenkov
,
A.
Syrkin
,
L.
Shapovalov
,
A.
Volkova
, and
V.
Ivantsov
,
Jpn. J. Appl. Phys., Part 1
52
,
08JB22
(
2013
).
8.
A.
Usui
,
ECS J. Solid State Sci. Technol.
2
,
N3045
(
2013
).
9.
K.
Yamano
,
M.
Ueno
,
H.
Furuya
,
N.
Okada
, and
K.
Tadamoto
,
J. Cryst. Growth
358
,
1
(
2012
).
10.
T.
Sato
,
S.
Okano
,
T.
Goto
,
T.
Yao
,
R.
Seto
,
A.
Sato
, and
H.
Goto
,
Jpn. J. Appl. Phys., Part 1
52
,
08JA08
(
2013
).
11.
S.
Kurin
,
A.
Antipov
,
I.
Barash
,
A.
Roenkov
,
H.
Helava
,
S.
Tarasov
,
E.
Menkovich
,
I.
Lamkin
, and
Yu.
Makarov
,
Phys. Status Solidi C
10
,
289
(
2013
).
12.
D.
Tsvetkov
,
Yu.
Melnik
,
A.
Davydov
,
A.
Shapiro
,
O.
Kovalenkov
,
J. B.
Lam
,
J. J.
Song
, and
V.
Dmitriev
,
Phys. Status Solidi A
188
,
429
(
2001
).
13.
I.-H.
Lee
,
A. Y.
Polyakov
,
N. B.
Smirnov
,
A. V.
Govorkov
,
E. A.
Kozhukhova
,
V. M.
Zaletin
,
I. M.
Gazizov
,
N. G.
Kolin
, and
S. J.
Pearton
,
J. Vac. Sci. Technol., B
30
,
021205
(
2012
).
14.
E. B.
Yakimov
,
P. S.
Vergeles
,
A. Y.
Polyakov
,
N. B.
Smirnov
,
A. V.
Govorkov
,
I.-H.
Lee
,
C. R.
Lee
, and
S. J.
Pearton
,
Appl. Phys. Lett.
90
,
152114
(
2007
).
15.
E. B.
Yakimov
,
S. S.
Borisov
, and
S. I.
Zaitsev
,
Semiconductors
41
,
411
(
2007
).
16.
S.
Mahajan
,
Appl. Phys. Lett.
80
,
4321
(
2002
).
17.
S.
Lin
,
Z.
Chen
,
Y.
Yang
,
S.
Lin
,
Y.
Ba
, and
C.
Yang
,
CrystEngComm
14
,
1588
(
2012
).
18.
D.
Cherns
,
W. T.
Young
, and
F.
Ponce
,
Mater. Sci. Eng., B
50
,
76
(
1997
).
19.
E.
Valcheva
,
T.
Paskova
, and
B.
Monemar
,
J. Cryst. Growth
255
,
19
(
2003
).
20.
T. B.
Wei
,
R. F.
Duan
,
J. X.
Wang
,
J. M.
Li
,
Z. Q.
Huo
, and
J. P.
Zeng
,
Microelectron. J.
39
,
1556
(
2008
).
21.
C.-Y.
Cho
,
M.-K.
Kwon
,
S.-J.
Lee
,
S.-H.
Han
,
J.-W.
Kang
,
S.-E.
Kang
,
D.-Y.
Lee
, and
S.-J.
Park
,
Nanotechnology
21
,
205201
(
2010
).
22.
C.-Y.
Cho
,
K. S.
Kim
,
S.-J.
Lee
,
M.-K.
Kwon
,
H.
Ko
,
S.-T.
Kim
,
G.-Y.
Jung
, and
S.-J.
Park
,
Appl. Phys. Lett.
99
,
041107
(
2011
).
23.
K.
Shiojima
and
T.
Suemitsu
,
J. Vac. Sci. Technol., B
21
,
698
(
2003
).
You do not currently have access to this content.