We demonstrate that 3.5% in-plane lattice mismatch between GaN (0001) epitaxial layers and SiC (0001) substrates can be accommodated without triggering extended defects over large areas using a grain-boundary-free AlN nucleation layer (NL). Defect formation in the initial epitaxial growth phase is thus significantly alleviated, confirmed by various characterization techniques. As a result, a high-quality 0.2-μm thin GaN layer can be grown on the AlN NL and directly serve as a channel layer in power devices, like high electron mobility transistors (HEMTs). The channel electrons exhibit a state-of-the-art mobility of >2000 cm2/V-s, in the AlGaN/GaN heterostructures without a conventional thick C- or Fe-doped buffer layer. The highly scaled transistor processed on the heterostructure with a nearly perfect GaN–SiC interface shows excellent DC and microwave performances. A peak RF power density of 5.8 W/mm was obtained at VDSQ = 40 V and a fundamental frequency of 30 GHz. Moreover, an unpassivated 0.2-μm GaN/AlN/SiC stack shows lateral and vertical breakdowns at 1.5 kV. Perfecting the GaN–SiC interface enables a GaN–SiC hybrid material that combines the high-electron-velocity thin GaN with the high-breakdown bulk SiC, which promises further advances in a wide spectrum of high-frequency and power electronics.

1.
S. K.
Mathis
,
A. E.
Romanov
,
L. F.
Chen
,
G. E.
Beltz
,
W.
Pompe
, and
J. S.
Speck
, “
Modeling of threading dislocation reduction in growing GaN layers
,”
Phys. Status Solidi A
179
,
125
(
2000
).
2.
F. A.
Marino
,
N.
Faralli
,
T.
Palacios
,
D. K.
Ferry
,
S. M.
Goodnick
, and
M.
Saraniti
, “
Effects of threading dislocations on AlGaN/GaN high-electron mobility transistors
,”
IEEE Trans. Electron Devices
57
,
353
(
2010
).
3.
M.
Ishida
,
T.
Ueda
,
T.
Tanaka
, and
D.
Ueda
, “
GaN on Si technologies for power switching devices
,”
IEEE Trans. Electron Devices
60
,
3053
(
2013
).
4.
F. A.
Ponce
,
B. S.
Krusor
,
J. S.
Major
, Jr.
,
W. E.
Plano
, and
D. F.
Welch
, “
Microstructure of GaN epitaxy on SiC using AlN buffer layers
,”
Appl. Phys. Lett.
67
,
410
(
1995
).
5.
B.
Morana
,
F.
Wu
,
A. E.
Romanov
,
U. K.
Mishra
,
S. P.
Denbaars
, and
J. S.
Speck
, “
Structural and morphological evolution of GaN grown by metalorganic chemical vapor deposition on SiC substrates using an AlN initial layer
,”
J. Cryst. Growth
273
,
38
(
2004
).
6.
Z. J.
Reitmeier
,
S.
Einfeldt
,
R. F.
Davis
,
X.
Zhang
,
X.
Fang
, and
S.
Mahajan
, “
Surface and defect microstructure of GaN and AlN layers grown on hydrogen-etched 6H-SiC (0001) substrates
,”
Acta Mater.
58
,
2165
(
2010
).
7.
E.
Cho
,
A.
Mogilatenko
,
F.
Brunner
,
E.
Richter
, and
M.
Weyers
, “
Impact of AlN nucleation layer on strain in GaN grown on 4H-SiC substrates
,”
J. Cryst. Growth
371
,
45
(
2013
).
8.
A.
Sarua
,
H.
Ji
,
K. P.
Hilton
,
D. J.
Wallis
,
M. J.
Uren
,
T.
Martin
, and
M.
Kuball
, “
Thermal boundary resistance between GaN and substrate in AlGaN/GaN electronic devices
,”
IEEE Trans. Electron Devices
54
,
3152
(
2007
).
9.
A.
Manoi
,
J. W.
Pomeroy
,
N.
Killat
, and
M.
Kuball
, “
Benchmarking of thermal boundary resistance in AlGaN/GaN HEMTs on SiC substrates: Implications of the nucleation layer microstructure
,”
IEEE Trans. Electron Devices
31
,
1395
(
2010
).
10.
E.
Bahat-Treidel
,
F.
Brunner
,
O.
Hilt
,
E.
Cho
,
J.
Wurfl
, and
G.
Trankle
, “
AlGaN/GaN/GaN:C back barrier HFET with breakdown voltage
,”
IEEE Trans. Electron Devices
57
,
3050
(
2010
).
11.
S.
Heikman
,
S.
Keller
,
S. P.
DenBarrs
, and
U. K.
Mishira
, “
Growth of Fe doped semi-insulating GaN by metalorganic chemical vapor deposition
,”
Appl. Phys. Lett.
81
,
439
(
2002
).
12.
M. J.
Uren
,
J.
Möreke
, and
M.
Kuball
, “
Buffer Design to minimize current collapse in GaN AlGaN HFETs
,”
IEEE Trans. Electron Devices
59
,
3327
(
2012
).
13.
J.-T.
Chen
,
J. W.
Pomeroy
,
N.
Rorsman
,
C.
Xia
,
C.
Virojanadara
,
U.
Forsberg
,
M.
Kuball
, and
E.
Janzén
,
J. Cryst. Growth
428
,
54
(
2015
).
14.
J.-T.
Chen
,
E.
Janzén
,
N.
Rorsman
,
M.
Thorsell
,
M.
Andersson
, and
O.
Kordina
, “
Carbon-doped GaN on SiC materials for low-memory-effect devices
,”
ECS Trans.
75
,
61
(
2016
).
15.
J.-T.
Chen
,
U.
Forsberg
, and
E.
Janzén
, “
Impact of residual carbon on two-dimensional electron gas properties in AlGaN/GaN heterostructure
,”
Appl. Phys. Lett.
102
,
193506
(
2013
).
16.
J.-T.
Chen
,
I.
Persson
,
D.
Nilsson
,
C.-W.
Hsu
,
J.
Palisaitis
,
U.
Forsberg
,
P. O. Å.
Persson
, and
E.
Janzén
, “
Room-temperature mobility above 2200 cm2/V·s of two-dimensional electron gas in a sharp-interface AlGaN/GaN heterostructure
,”
Appl. Phys. Lett.
106
,
251601
(
2015
).
17.
B.
Heying
,
X. H.
Wu
,
S.
Keller
,
Y.
Li
,
D.
Kapolnek
,
B. P.
Keller
,
S. P.
DenBaars
, and
J. S.
Speck
, “
Role of threading dislocation structure on the x-ray diffraction peak widths in epitaxial GaN films
,”
Appl. Phys. Lett.
68
(
5
),
643
(
1996
).
18.
J.
Bergsten
,
J.-T.
Chen
,
S.
Gustafsson
,
A.
Malmros
,
U.
Forsberg
,
M.
Thorsell
,
E.
Janzén
, and
N.
Rorsman
, “
Performance enhancement of microwave GaN HEMTs without an AlN-exclusion layer using an optimized AlGaN/GaN interface growth process
,”
IEEE Trans. Electron Devices
63
,
333
(
2016
).
19.
A.
Malmros
,
H.
Blanck
, and
N.
Rorsman
, “
Electrical properties, microstructure, and thermal stability of Ta-based ohmic contacts annealed at low temperature for GaN HEMTs
,”
Semicond. Sci. Technol.
26
,
075006
(
2011
).
20.
H.
Amano
,
Y.
Baines
,
E.
Beam
,
M.
Borga
,
T.
Bouchet
,
P. R.
Chalker
,
M.
Charles
,
K. J.
Chen
,
N.
Chowdhury
,
R.
Chu
 et al, “
The 2018 GaN power electronics roadmap
,”
J. Phys. D: Appl. Phys.
51
,
163001
(
2018
).

Supplementary Material

You do not currently have access to this content.