High growth rate deposition of oriented InN pillar crystals

Article abstract of DOI:10.1016/j.ssc.2005.03.003

High growth rate deposition of highly oriented indium nitride (InN) pillar crystals were successfully grown on Si(100) substrate prepared under atmospheric pressure using a halide CVD method (AP-HCVD). The growth rate of InN pillar crystal can be enhanced threefold by AP-HCVD system with metal halide dual sources zone, and the maximum growth rate of 8.33 nm/s was achieved. X-ray diffraction and X-ray pole-figure analyses showed that the each InN pillar crystal grows with a different rotation angle around the 〈001〉 axis. Selected area transmission electron diffraction showed that that they are of high crystal quality.

Full text of DOI:10.1016/j.ssc.2005.03.003

Solid State Communications 134 (2005) 617–620
www.elsevier.com/locate/ssc
High growth rate deposition of oriented InN pillar crystals
a
Kikurou Takemoto , Naoyuki Takahashi
b,
b
*
, Takato Nakamura
a
Innovative Research Center, Shizuoka University, 3-5-1 Johoku, Hamamatus, Shizuoka 432-8561, Japan
b
Department of Materials Science and Technology, Faculty of Engineering, Shizuoka University, 3-5-1 Johoku, Hamamatus,
Shizuoka 432-8561, Japan
Received 24 January 2005; accepted 1 March 2005 by C.N.R. Rao
Available online 19 March 2005
Abstract
High growth rate deposition of highly oriented indium nitride (InN) pillar crystals were successfully grown on Si(100)
substrate prepared under atmospheric pressure using a halide CVD method (AP-HCVD). The growth rate of InN pillar crystal
can be enhanced threefold by AP-HCVD system with metal halide dual sources zone, and the maximum growth rate of
8
.33 nm/s was achieved. X-ray diffraction and X-ray pole-figure analyses showed that the each InN pillar crystal grows with a
cd ri yf f se t ra el n qt ur ao lt iat tyi .o n angle around the h001i axis. Selected area transmission electron diffraction showed that that they are of high
q 2005 Elsevier Ltd. All rights reserved.
PACS: 80
Keywords: A. InN; A. Pillar crystal; B. AP-HCVD; D. Crystal quality; D. High growth rate
1
. Introduction
GaAs and GaN. This means that the understanding of the
optical and structural properties of high quality InN brings
us further advance of light-emitting group III nitride device.
We have already reported that an atmospheric pressure
halide chemical vapor deposition (AP-HCVD) is an
appropriate technique for the preparation of InN pillar
crystals [12]. Advantages of this method are as follows; (a)
The pillar crystals are prepared by a simple reaction of
Recently, low-dimensional nano-structures and micro-
structures like wires or whisker of semiconductor materials
have attracted much attention due to their possible
applications in nano-scale or micro-scale electronics and
optoelectronic devices. Group III nitride semiconductor (Al,
Ga, In)N are currently the subject of much interest in their
fundamental physical properties and their potential for high-
temperature electronic devices and visible/near optoelec-
tronic devices [1]. However, the InN has not received as
much experimental attention as GaN [2–6] because of the
difficulties associated with the growth of high quality
crystals [7–11]. On the other hand, a large drift velocity of
InN at room temperature is very attractive, and would bring
better field effect transistors in comparison with those of
gaseous InCl
There is no need to do post-annealing. (c) High-purity InCl
used as a starting material is cheap compared with other
indium compounds such as In(CH and In(C used for
3 3
with NH under atmospheric pressure. (b)
3
3
)
3
2 5 3
H )
molecular beam epitaxy (MBE) and metal-organic chemical
vapor deposition (MOCVD). It should be noticed that there
is no report on the growth of the InN pillar crystals by means
of MBE and MOCVD to the best of the authors’ knowledge.
In this paper, we report the growth of InN pillar crystal on
Si(100) with a growth rate of 8.33 nm/s by AP-HCVD using
dual sources. In addition, we describe the results of their
detailed investigation carried out by various means, X-ray
*
Corresponding author. Tel./fax: C81 53 478 1197.
E-mail address: tntakah@ipc.shizuoka.ac.jp (N. Takahashi).
0038-1098/$ - see front matter q 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.ssc.2005.03.003

618
K. Takemoto et al. / Solid State Communications 134 (2005) 617–620
Fig. 1. Schematic illustration of AP-HCVD with dual sources zone.
pole-figure, scanning electron microscopy (SEM), trans-
mission electron microscopy (TEM) in conjunction with
selected area electron diffraction (SAED).
Fig. 2. SEM image of InN pillar crystal grown on Si(100) substrate.
2
. Experimental procedure
It was confirmed that the deposited InN under growth time
of 3600 s consists of the hexagonal pillars with the height of
30,000 nm and the diameter of 1000 nm. The growth rate
A schematic diagram of AP-HCVD apparatus using dual
sources for InN pillar crystal growth is show in Fig. 1. So
(8.33 nm/s) increased by the increase of the InCl partial
3
far, the vapor of InCl as a source was supplied from one
3
pressure, which is threefold higher than the growth rate
source zone. To increase the growth rate, the vapor of InCl
was supplied from the dual source zone.
3
reported (2.77 nm/s) in the literature [12]. This high growth
rate deposition of InN has not been reported until now.
Interestingly, they are standing on the surface of the
substrate, and at the end of the pillar six triangle {103}
faces meet in a point at the top like hexagonal pyramid.
Fig. 3 shows the typical XRD pattern of the InN pillar
crystal grown on the Si(100) substrate. Resulting crystals on
the Si(100) substrate showed an intense X-ray diffraction
line appearing at 2qZ31.28 assigned to the (002) diffraction
of InN with hexagonal structure. This implies that the InN
pillar crystals have high orientation. An estimated lattice
constant of 0.5697 nm, which is slightly smaller than the
reported one of 0.57033 nm for the bulk InN powder, also
supported the formation of InN crystals [9].
The pillar crystal of InN were grown on a Si(100)
substrate under atmospheric pressure. The substrate was an
n-type Si(100) wafer with 0.05 U cm. InCl
was evaporated at a temperature of 523 K, and supplied to
the growth zone by purified N carrier gas. Partial pressures
of InCl and NH were adjusted independently by varying
3
in a source boat
2
3
3
the flow rates of the carrier gas. Typical experimental
conditions are summarized in Table 1.
The growth direction of respective pillar crystals on the
Si(100) surface was assessed by X-ray pole-figure (Rigaku,
ATX-G), and their quality was evaluated using a JEOL
JSM-5500LV SEM microscope and a JEOL JEM-200E
TEM microscope equipped with selected area electron
diffraction (SAED) accessory. The X-ray photoelectron
spectroscopy (XPS) spectra were measured using a
Shimadzu XRTOS-XSAM 800 X-ray photoelectron
spectrometer.
Fig. 4 shows the X-ray pole-figures of the hexagonal InN
pillar crystal. The measurements were carried out with fixed
u and 2q values corresponding to the hexagonal (004) and
3
. Results and discussion
Fig. 2 shows the SEM images of the InN crystal grown
on the Si(100) substrate under growth conditions in Table 1.
Table 1
Typical growth conditions
Substrate
InCl partial pressure
NH partial pressure
Si(100)
2
4.66!10 Pa
3
2.33!10 Pa
3
3
Carrier gas
N
2
K5
3 K1
Total flow rate
Growth temperature
Growth time
1.25!10 m s
923 K
Fig. 3. XRD pattern of the InN pillar crystal grown on the Si(100)
substrate.
3600 s

K. Takemoto et al. / Solid State Communications 134 (2005) 617–620
619
(
013) Bragg diffractions, in which the h013i axis is of 628 off
measurement, spot pattern was observed at the InN pillar
(Fig. 5(b)), indicating that at the InN pillar it has crystal
structure with high quality.
from the h001i direction. In order to see the distribution of
the growing direction of the InN pillars on the Si surface, the
u and 2q were fixed at the (004) diffraction peak (Fig. 4(a)).
It showed an intense diffraction at jZ908, but the spot
diffuses to jZ808. It is, therefore, presumed that the InN
pillars are grown at an angle of 80–908 to the Si surface.
When the u and 2q were fixed at the (013) diffraction peak, a
strong diffraction ring at jZ20–408 was observed indepen-
dent of the f value ranging from 0 to 3608 (Fig. 3(b)). This
means that each InN pillar crystal is grown with different in-
plane rotation around the h100i axis.
The indium and nitrogen contents of the InN pillar
crystal were determined by XPS. The two strong peaks at
396.1 and 443.6 eV correspond to the N(1s) and In(3d)
binding energy, respectively, for the InN pillar crystal. No
obvious peak for indium oxide (444.9 eV) for In3d5/2 in
In O and 445.0 eV in In(OH) is observed. The ratio of the
2
3
3
quantification of peaks N:In is closed to 1:1, which is
consistent with that found by elemental analysis. Also, it
was found that no peak assigned to carbon, chlorine and
oxygen is observed for the InN pillar crystals prepared in
this study so that their contents are less than 1 at.%,
implying that there is little contamination of these elements.
TEM and SAED were employed in order to examine the
microstructure and crystallinity of the InN pillar crystal.
Fig. 5 shows the cross-sectional TEM image of a whole
pillar crystal along with the SAED patterns of the InN pillar
crystal grown on the Si(100) substrate. For the TEM
measurements the crystals were sliced perpendicular to the
substrate. As is seen in the TEM image (Fig. 5(a)), there are
light gray and dark gray areas observed in the InN crystals.
This implies that the InN pillar crystals have single
crystalline structure with defects. As for the SAED a
Fig. 5. (a) TEM image and (b) SAED pattern of the InN pillar
crystal.
Fig. 4. X-ray pole-figure of the InN pillar crystal grown on Si(100).

620
K. Takemoto et al. / Solid State Communications 134 (2005) 617–620
Therefore, apparent that the InN pillar crystals are high
quality crystal form and that as the InN grows the
crystallinity is improved significantly.
[2] S. Nakamura, T. Mukai, M. Senoh, Appl. Phys. Lett. 64 (1994)
1687.
[
3] S. Nakamura, T. Matsushita, Y. Sugimoto, H. Kiyoku, Appl.
Phys. Lett. 69 (1996) 3034.
[
[
4] W. Han, S. Fan, Q. Li, Y. Hu, Science 277 (1997) 1287.
5] M. Yoshizawa, A. Kikuchi, M. Mori, N. Fujita, K. Kishino,
Jpn. J. Appl. Phys. 36 (1997) L459.
4
. Conclusions
[
6] S. Nakamura, M. Senoh, S. Nagahama, N. Iwasa, T. Yamada,
T. Matsushita, H. Kiyoku, Y. Sugimoto, T. Kozaki,
U. Umemoto, M. Sato, K. Chocho, Appl. Phys. Lett. 72
We reported the high growth rate deposition of InN pillar
crystal by the AP-HCVD with dual sources. The pillar
crystals of InN were deposited on Si(100) at a growth rate of
(
1998) 2014.
8
.33 nm/s (30 mm/h), which is threefold higher than the
[
[
7] J.B. MacChesney, P.M. Bridenbaugh, P.B. O’Connor, Mater.
Res. Bull. 5 (1970) 783.
growth rate reported in the literature. Detailed characteriz-
ation of the InN pillar crystals has been performed using
SEM, XRD, X-ray pole-figure, TEM, SAD and SIMS. The
as-deposited pillars are a crystal with c-axis orientation, but
each of them grows with a different rotation angle around
8] T.L. Tansley, C.P. Foley, Electron. Lett. 20 (1984) 1066.
[9] T.L. Tansley, C.P. Foley, J. Appl. Phys. 59 (1986) 3241.
[10] R.D. Jones, K. Rose, J. Phys. Chem. Solids 48 (1987) 587.
[11] A. Wakahara, T. Tsuchiya, A. Yoshida, J. Crystal Growth 99
(1990) 385.
te hx ec ehl 1l e0 n0 ti. axis. The quality of the InN pillar crystal is
[12] N.
Takahashi, A. Niwa, T. Takahashi, T. Nakamura,
M. Yoshioka, J. Mater. Chem. 172 (1997) 298.
References
[1] S. Strite, H. Morkoc, J. Vac. Sci. Technol., B 10 (1992) 1237.