Journal of Alloys and Compounds 479 (2009) 812–815
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Journal of Alloys and Compounds
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Growth of well-oriented Al
x
In
1-x
N films by sputtering at low temperature
C.J. Dong
a
, M. Xu
a,b,∗
, Q.Y. Chen
a
, F.S. Liu
c
, H.P. Zhou
a
, Y. Wei
a
, H.X. Ji
a
a
Lab for Low-dimensional Structure Physics, Institute of Solid State Physics, Sichuan Normal University, Chengdu 610068, China
b
International Center for Material Physics, Chinese Academy of Sciences, Shenyang 110016, PR China
c
Research Center of V-Ti materials, Panzhihua University, Panzhihua 617000, China
article info
Article history:
Received 5 December 2008
Received in revised form 13 January 2009
Accepted 15 January 2009
Available online 31 January 2009
PACS:
78.20.Ek
78.66.Fd
Keywords:
AlxIn1-xN film
Magnetron sputtering
Crystallinity
Resistance
abstract
Al
x
In
1-x
N films with an AlN buffer were deposited on different substrates (including Si(1 1 1), sapphire,
and glass) by radio-frequency (RF) magnetron sputtering at a low temperature of 300
◦
C. The morphol-
ogy and structure analysis revealed that the Al
x
In
1-x
N films grown on Si(1 1 1) and sapphire are of high
orientation and good crystallinity with a bandgap energy (E
g
) of less than 2.41 eV. The sheet resistance of
Al
x
In
1-x
N film grown on Si(1 1 1) and sapphire is approximately 40 /. These results are highly relevant
to the development of effective nitride photovoltaic materials.
© 2009 Elsevier B.V. All rights reserved.
1. Introduction
Group III nitrides are among the most promising optoelectronic
materials because they possess excellent intrinsic properties such
as a wide range of direct transition-type energy bandgaps from
6.2 eV for AlN [1,2] to 0.6–0.8 eV for InN [3–6], strong bond between
nitrogen and each group III atom, high thermal conductivity, high
electron saturation velocity [6–9], and several others. As such, these
materials offer various promising applications in high-efficiency
light emitting diodes (LEDs), laser diodes (LDs), photodiodes (PDs)
operating in visible and ultraviolet (UV) regions, as well as high-
power electronic devices. Recent investigation by Senda et al. [10]
showed that AlInN is more suitable than AlGaN for UV photodiodes
with a cutoff wavelength in the UV-C range. In spite of this, there
have been only a few reports on the growth of Al
x
In
1-x
N ternary
material [11–17]. The difficulty in the epitaxial growth arises from
phase separation [7–19] caused by the large mismatch of covalent
bond lengths and the difference in the thermal stability of AlN and
InN. Guo et al. [20] reported that the fabrication of single-crystal
Al
x
In
1-x
N films with x ranging from 0 to 0.14 in the low Al content
regime using metal organic vapor phase epitaxy (MOVPE). There-
after, Kim et al. [21] reported on the MOVPE growth of Al
x
In
1-x
N
∗
Corresponding author at: Institute of Solid State Physics, Sichuan Normal Uni-
versity, Chengdu 610068, China. Tel.: +86 28 84760805; fax: +86 28 84480790.
E-mail address: hsuming 2001@yahoo.com.cn (M. Xu).
with x ranging from 0.92 to 0.99 in the very high Al content regime.
In 2000, Yamaguchi et al. [22] successfully fabricated Al
x
In
1-x
N
films on GaN with x from 0.42 to 0.86 using MOVPE at 720
◦
C.
Recently, Peng et al. [23] reported on the possibility of the growth of
polycrystalline Al
x
In
1-x
N films with x ranging from 0 to 1 by sput-
tering. Very recently, Cheng et al. [24] reported on the growth of
AlInN using metal organic vapor phase epitaxy, a small full-width at
half-maximum (only 219.8 arcsec) of the AlInN diffraction peak was
observed by double crystal X-ray diffraction for the indium content
of 20.8%. Since AlInN is very important, in this work, we show the
possibility of the growth of Al
x
In
1-x
N with good crystal structure
and electrical properties in a low-cost process (i.e., growth at low
temperature, low-cost methods such as magnetron sputtering, etc.).
2. Growth and characterization of Al
x
In
1-x
N films
In this study, Al
x
In
1-x
N films were grown on different substrates
including Si(1 1 1), glass and sapphire by radio-frequency (RF)
magnetron sputtering. A series of preliminary experiments indi-
cated that 300
◦
C was the ideal temperature for growing Al
x
In
1-x
N
films. Prior to the growth of the Al
x
In
1-x
N film, substrates used
in this study were chemically cleaned before being loaded into
the sputtering chamber. A typical base pressure of 4.5 × 10
-5
Pa
is routinely achieved by a turbomolecular pumping system. To
accommodate the large lattice mismatch between the substrates
and the Al
x
In
1-x
N layer, an AlN buffer layer was first grown on the
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doi:10.1016/j.jallcom.2009.01.075