Influence of small miscuts on self-ordered growth of Ge nanoislands
Using high-resolution X-ray diffraction (HRXRD), we have investigated lateral ordering the nanoislands formed from Ge wetting layer of various thicknesses deposited on a strained Si₁₋xGex sublayer. We observed that the high lateral ordering degree is initiated by ordered modulation of non-uniform...
Saved in:
| Published in: | Semiconductor Physics Quantum Electronics & Optoelectronics |
|---|---|
| Date: | 2011 |
| Main Authors: | , , , , , , , |
| Format: | Article |
| Language: | English |
| Published: |
Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України
2011
|
| Online Access: | https://nasplib.isofts.kiev.ua/handle/123456789/117796 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Journal Title: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Cite this: | Influence of small miscuts on self-ordered growth of Ge nanoislands / O.Yo. Gudymenko, V.P. Kladko, O.M. Yefanov, M.V. Slobodian, Yu.S.Polischuk, Z.F. Krasilnik, D.V. Lobanov, А.А. Novikov // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2011. — Т. 14, № 4. — С. 389-392. — Бібліогр.: 18 назв. — англ. |
Institution
Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
nasplib_isofts_kiev_ua-123456789-117796 |
|---|---|
| record_format |
dspace |
| spelling |
Gudymenko, O.Yo. Kladko, V.P. Yefanov, O.M. Slobodian, M.V. Polischuk, Yu.S. Krasilnik, Z.F. Lobanov, D.V. Novikov, А.А. 2017-05-26T17:45:36Z 2017-05-26T17:45:36Z 2011 Influence of small miscuts on self-ordered growth of Ge nanoislands / O.Yo. Gudymenko, V.P. Kladko, O.M. Yefanov, M.V. Slobodian, Yu.S.Polischuk, Z.F. Krasilnik, D.V. Lobanov, А.А. Novikov // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2011. — Т. 14, № 4. — С. 389-392. — Бібліогр.: 18 назв. — англ. 1560-8034 PACS 68.37.Ef, 81.07.Ta, 81.16.Rf https://nasplib.isofts.kiev.ua/handle/123456789/117796 Using high-resolution X-ray diffraction (HRXRD), we have investigated lateral ordering the nanoislands formed from Ge wetting layer of various thicknesses deposited on a strained Si₁₋xGex sublayer. We observed that the high lateral ordering degree is initiated by ordered modulation of non-uniform deformation fields. This modulation is induced by small (∼0.3°) misorientation of Si substrate from [001] direction. Finally, we show that the miscut can be the source of perfectly ordered nanoisland arrays in two dimensions when the growth is performed on the strained SiGe (001) sublayer. The effect of substrate miscut can be amplified tuning the deviation of buffer layer surface from [001] growth direction via increasing the Ge content. The authors acknowledge the financial support of the National Academy of Sciences of Ukraine (projects No 3.5.1.12, No 3.5.1.30) and State Agency for Science, Innovation and Informatization of Ukraine (project M/ 212 − 2011). en Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України Semiconductor Physics Quantum Electronics & Optoelectronics Influence of small miscuts on self-ordered growth of Ge nanoislands Article published earlier |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| title |
Influence of small miscuts on self-ordered growth of Ge nanoislands |
| spellingShingle |
Influence of small miscuts on self-ordered growth of Ge nanoislands Gudymenko, O.Yo. Kladko, V.P. Yefanov, O.M. Slobodian, M.V. Polischuk, Yu.S. Krasilnik, Z.F. Lobanov, D.V. Novikov, А.А. |
| title_short |
Influence of small miscuts on self-ordered growth of Ge nanoislands |
| title_full |
Influence of small miscuts on self-ordered growth of Ge nanoislands |
| title_fullStr |
Influence of small miscuts on self-ordered growth of Ge nanoislands |
| title_full_unstemmed |
Influence of small miscuts on self-ordered growth of Ge nanoislands |
| title_sort |
influence of small miscuts on self-ordered growth of ge nanoislands |
| author |
Gudymenko, O.Yo. Kladko, V.P. Yefanov, O.M. Slobodian, M.V. Polischuk, Yu.S. Krasilnik, Z.F. Lobanov, D.V. Novikov, А.А. |
| author_facet |
Gudymenko, O.Yo. Kladko, V.P. Yefanov, O.M. Slobodian, M.V. Polischuk, Yu.S. Krasilnik, Z.F. Lobanov, D.V. Novikov, А.А. |
| publishDate |
2011 |
| language |
English |
| container_title |
Semiconductor Physics Quantum Electronics & Optoelectronics |
| publisher |
Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
| format |
Article |
| description |
Using high-resolution X-ray diffraction (HRXRD), we have investigated
lateral ordering the nanoislands formed from Ge wetting layer of various thicknesses
deposited on a strained Si₁₋xGex sublayer. We observed that the high lateral ordering
degree is initiated by ordered modulation of non-uniform deformation fields. This
modulation is induced by small (∼0.3°) misorientation of Si substrate from [001]
direction. Finally, we show that the miscut can be the source of perfectly ordered
nanoisland arrays in two dimensions when the growth is performed on the strained SiGe
(001) sublayer. The effect of substrate miscut can be amplified tuning the deviation of
buffer layer surface from [001] growth direction via increasing the Ge content.
|
| issn |
1560-8034 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/117796 |
| citation_txt |
Influence of small miscuts on self-ordered growth of Ge nanoislands / O.Yo. Gudymenko, V.P. Kladko, O.M. Yefanov, M.V. Slobodian, Yu.S.Polischuk, Z.F. Krasilnik, D.V. Lobanov, А.А. Novikov // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2011. — Т. 14, № 4. — С. 389-392. — Бібліогр.: 18 назв. — англ. |
| work_keys_str_mv |
AT gudymenkooyo influenceofsmallmiscutsonselforderedgrowthofgenanoislands AT kladkovp influenceofsmallmiscutsonselforderedgrowthofgenanoislands AT yefanovom influenceofsmallmiscutsonselforderedgrowthofgenanoislands AT slobodianmv influenceofsmallmiscutsonselforderedgrowthofgenanoislands AT polischukyus influenceofsmallmiscutsonselforderedgrowthofgenanoislands AT krasilnikzf influenceofsmallmiscutsonselforderedgrowthofgenanoislands AT lobanovdv influenceofsmallmiscutsonselforderedgrowthofgenanoislands AT novikovaa influenceofsmallmiscutsonselforderedgrowthofgenanoislands |
| first_indexed |
2025-11-24T04:19:36Z |
| last_indexed |
2025-11-24T04:19:36Z |
| _version_ |
1850841420341968896 |
| fulltext |
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2011. V. 14, N 4. P. 389-392.
© 2011, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
389
PACS 68.37.Ef, 81.07.Ta, 81.16.Rf
Influence of small miscuts on self-ordered growth of Ge nanoislands
O.Yo. GudymenkoP
1
P, V.P. KladkoP
1
P, O.M. YefanovP
1
P, M.V. SlobodianP
1
P, Yu.S. PolischukP
1
P,
Z.F. KrasilnikP
2
P, D.V. LobanovP
2
P, А.А. NovikovP
2
P
P
1
PV. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine,
45, prospect Nauky, 03028 Kyiv, Ukraine
P
2
PInstitute of Microstructure Physics, RAS,
603600 Nizhny Novgorod, GSP-105, Russia
Abstract. Using high-resolution X-ray diffraction (HRXRD), we have investigated
lateral ordering the nanoislands formed from Ge wetting layer of various thicknesses
deposited on a strained xx1 GeSi − sublayer. We observed that the high lateral ordering
degree is initiated by ordered modulation of non-uniform deformation fields. This
modulation is induced by small (∼0.3°) misorientation of Si substrate from [001]
direction. Finally, we show that the miscut can be the source of perfectly ordered
nanoisland arrays in two dimensions when the growth is performed on the strained SiGe
(001) sublayer. The effect of substrate miscut can be amplified tuning the deviation of
buffer layer surface from [001] growth direction via increasing the Ge content.
Keywords: SiGe nanoislands, miscut, deformation field, high-resolution X-ray
diffraction.
Manuscript received 20.07.11; revised manuscript received 29.08.11; accepted for
publication 14.09.11; published online 30.11.11.
1. Introduction
Self-organization is the most perspective method to form
nanoislands during epitaxial growth [1]. But it is known
that the spontaneous nucleation of nanoislands in accord
with the classical Stranski-Krastanov mechanism is
accompanied by their chaotic arrangement [2]. Today
several techniques are used to obtain ordered arrays of
Ge(Si) nanoislands. In recent years, to organize arrays of
Ge(Si) islands, they use their growth on an undulating
surface formed by deposition of x1xSiGe − layers [3],
selective epitaxial growth of Si and Ge in windows and
grooves of SiOB2B [4], growth on relaxed buffer layers
xx1 GeSi − , containing a grid of misfit dislocations [5],
the growth in pre-structured Si substrates [6].
Application of these techniques allows obtaining the
ordered chains of nanoislands with a high linear density,
but in this case their two-dimensional density still
remains low.
The possibility of spontaneous spatial ordering
appears with elastic interaction of neighbor nanoislands,
when the distance between them is of the order of their
sizes in the growth plane [7, 8]. Reduction of this
distance can be achieved by increasing the nanoisland
density via decreasing the growth temperature. But it is
followed also with reduction of the nanoisland size.
One of the most effective techniques to form dense
ordered arrays of GeSi islands can be their growth on
x1xSiGe − buffer layers [9, 10]. It is known from [11]
that the deposition of strained SiGe layer on Si(001)
increases the growth plane roughness. This, in turn,
leads to a decrease in the diffusion length of surface
adatoms. As a result, the surface density of nanoislands
increases with increasing their lateral interaction through
the elastic deformation fields. This interaction facilitates
nanoisland ordering in the growth plane.
The self-ordering effect of nanoislands grown on
SiGe buffer layers can be amplified by unintentional
miscut within the range of 0.2–0.5º of commercially
available substrates Si(001). Until recently, the influence
of misorientation of the substrate vicinal surface on
epitaxial growth was not specially attended [12]. The
step edges of atomic layers specify the modulation of
non-uniform deformation fields in the deposited buffer
layer [13], which, in turn, becomes the pattern for the
ordered formation of nanoisland arrays.
In this paper, we investigate the influence of
substrate and buffer miscut on the lateral ordering the
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2011. V. 14, N 4. P. 389-392.
© 2011, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
390
SiGe nanoislands formed on the xx1 GeSi − sublayer in
dependence on the Ge amount. We demonstrate that
high homogeneity in distribution of islands can be
achieved when depositing 10 monolayers (ML) of Ge.
Detailed characterization reveals that the direction of
ordering the islands is given by the miscut direction,
which has not been observed previously. In particular,
we showed that the lateral period of nanoislands depends
on the substrate misorienation value.
The samples under investigation were grown using
molecular-beam epitaxy on Si(001) substrates with the
controlled miscut 0.3º at 700 ºC. After thermal
refinement of substrate in the growth chamber and the
growth of 100-nm thick Si buffer layer, the 10-nm thick
strained xx1 GeSi − sublayer with Ge fraction x =
0.22±0.02 was deposited. Self-assembled Ge
nanoislands were formed on xx1 GeSi − sublayer in
Stranski-Krastanov growth mode during deposition of
the Ge layer with various thicknesses from 9 to 11 ML.
HRXRD measurements were performed with
PANalytical X’Pert PRO MRD XL diffractometer. To
obtain information about strains and their relaxation
during nanoisland ordering, the reflection curves (RCs)
and high-resolution reciprocal space maps (HR-RSMs)
were measured for symmetrical 004 and asymmetrical
113, 404 reflections [14].
Si substrate was slightly misoriented in the
direction close to [ 100− ], with the miscut components
along [ 101−− ] near 0.4º and along [ 110− ] – 0.3º. The
buffer layer, in its turn, was 0.2º misoriented only in the
[ 110− ] direction.
The layer misorientation increases with increasing
the Ge content due to the lattice mismatch. The nature of
layer misorientation on miscut substrate is given in [15].
Substrate surface deviations from exact
crystallographic orientation are the triggers for the
formation of anisotropically ordered system of quantum
nanoislands due to different conditions for diffusion
processes. Besides, the growth of strained SiGe layer on
miscut substrate will cause the periodical strain
modulation in the places of breaking the atomic steps
[15], which increases the ordering degree (Fig. 1). The
unit cells close to each SiGe/Si interface will be
inhomogeneously strained because of the atomic
steps [16].
Modulation of elastic strain fields is caused by the
reduction of chemical potential in the places with greater
mismatch between Si substrate and SiGe layer. The
following growth of Ge wetting layer (WL) reaches the
critical thickness at a less equivalent amount of
deposited Ge. In other words, the nanoislands are formed
in the places of elastic strain localization [15]. In the
case of vicinal surface of xx1 GeSi − layer, the non-
uniform fields of elastic strains, which could decrease
the critical thickness of WL, are absent.
Fig. 2 presents the RC’s obtained in asymmetrical
diffraction geometry for 113 and 404 reflections
measured in {110} and {100} scattering planes. One can
clearly see the system of lateral satellites, confirming the
ordering of nanoislands. The distance between lateral
satellites allows us to determine the mean distance
between nanoislands: from 113 reflections – the distance
along [110] direction, from mutually perpendicular (404)
scans – along [100] and [010]. These values are given in
Table.
Reciprocal space maps measured for asymmetrical
113 and 404 reflections confirmed our suggestions about
ordering character in dependence on the thickness of
deposited Ge (Fig. 3).
The nanoisland ordering degree increases with Ge
content increasing from 9 to 10 ML. This is seen from
the appearance of the 2P
nd
P-order lateral satellites on RCs
and HR-RSMs (Fig. 3b). When the Ge layer thickness is
11 ML, these satellites disappear because of the bad
structural properties [17]. Broadening the diffuse
scattering background perpendicular to the diffraction
vector can indicate the appearance of chaotically
distributed misfit dislocations leading to the structural
relaxation (Fig. 3с).
One can observe the additional “streaks” on 113
HR-RSMs close to crystal truncation rod. We suppose
that this diffraction effect is the result of mirror
reflection of X-rays from island facets aligned along
{110}. In 404 HR-RSMs, we did not observe this effect,
since there is no scattering from facet edges. These
streaks can be criteria of ordering the planar quantum
dots.
Fig. 1. Periodical strain modulation in the SiGe/Si with
unintentional miscut.
Fig. 2. ω-scans for samples with 9, 10 and 11 МL of deposited
Ge (1, 2, 3), respectively.
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2011. V. 14, N 4. P. 389-392.
© 2011, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
391
As it was showed in [18], increase in the deposited
Ge nominal thickness from 9 to 10 ML improves the
ordering degree, which is seen from the high-order
maxima in AFM autocorrelation profiles. A further
increase in the Ge thickness up to 11 ML changes the
size and shape of nanoislands that appear to be of an
elliptical shape. This is a result of anisotropic character
of material surface diffusion.
The decrease in the lateral period of nanoislands
versus the deposited Ge thickness is evidently given by
an increase in their density [18]. The observed difference
of lateral period in mutually perpendicular directions for
113 reflections as well as for 404 reflections is a result
of the difference of nanoislands planar unit cell from
their square shape due to surface diffusion anisotropy.
Note that the angle between nanoisland distribution
directions was measured to be ≈82º. Thus, the planar
unit cell representing the two-dimensional arrangement
of nanoislands is an oblique lattice.
We have investigated the spatial ordering of
nanoislands grown with different thicknesses of
deposited Ge layer on the xx1 GeSi − sublayer. It has
been shown that surface-ordered fields of elastic strains
initiated by misorientation of substrate and buffer layers
amplify the role of interdiffusion processes, which gives
the anomalously great flux of atoms from the buffer
sublayer into the islands. The ordered character of
deformation fields gives rise to the formation of self-
ordered nanoisland system. The optimal nanoisland
ordering was observed at 10 ML Ge deposition.
The authors acknowledge the financial support of
the National Academy of Sciences of Ukraine (projects
No 3.5.1.12, No 3.5.1.30) and State Agency for Science,
Innovation and Informatization of Ukraine (project
2011212/M − ).
References
1. J. Phillips, Evaluation of the fundamental
properties of quantum dot infrared detectors // J.
Appl. Phys. 91, p. 4590 (2002).
2. V.A. Shchukin, N.N. Ledentsov, D. Bimberg,
Epitaxy of Nanostructures. NanoScience and
Technology. Springer, 387, 2004.
3. Y. Wakayama, G. Gerth, P. Werner, U. Gosele,
L.V. Sokolov, Structural transition of Ge dots
induced by submonolayer carbon on Ge wetting
layer // Appl. Phys. Lett. 77, p. 2328-2330 (2000).
4. S. Kim, N. Usami, and Y. Shiraki, Selective
epitaxial growth of dot structures on patterned Si
substrates by gas source molecular beam epitaxy //
Semiconductor Science and Technolology, 14,
p. 257-265 (1999).
5. S.Yu. Shiryaev, F. Jensen, J.L. Hansen
J.W. Petersen, A.N. Larsen, Nanoscale structuring
Table. TLateral period placement of islands along different crystallographic directions.TT
Ge
thickness 113 (0) 113 (90) 404 (45) 404 (–45)
Sublayer/
islands, х
Sublayer/
islands, εBxxB
9 МL 260 269 177 164 0.30/0.29 –0.014/–0.003
10 МL 255 246 172 0.32/0.31 –0.013/–0.001
11 МL 226 226 165 157 0.33/0.32 –0.012/0.001
Fig. 3. 113 HR-RSMs for samples with 9, 10 and 11 МL of deposited Ge (a, b, c), respectively.
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2011. V. 14, N 4. P. 389-392.
© 2011, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
392
by misfit dislocations in xx1 GeSi − /Si epitaxial
systems // Phys. Rev. Lett., 78, p. 503-506 (1997).
6. Zhenyang Zhong, A. Halilovic, T. Fromherz,
F. Schäffler, and G. Bauer, Two-dimensional
periodic positioning of self-assembled Ge islands
on prepatterned Si (001) substrates // Appl. Phys.
Lett. 82, p. 4779-4781 (2003).
7. D.N. Lobanov, A.V. Novikov, N.V. Vostokov,
Y.N. Drozdov, A.N. Yablonskiy, Z.F. Krasilnik,
M. Stoffel, U. Denker, O.G. Schmidt, Growth and
photoluminescence of Ge(Si) self-assembled
islands obtained during the deposition of Ge on a
strained SiGe layer // Optical Materials, 27, p. 818
(2005).
8. P. Sutter, M.G. Lagally, Nucleationless three-
dimensional island formation in low-misfit
heteroepitaxy // Phys. Rev. Lett. 84, p. 4637-4640
(2000).
9. D.V. Yurasov, Yu.N. Drozdov, The critical
thickness of Stranski-Krastanow transition with
accounted segregation effect // Semiconductors, 42,
p. 563 (2008).
10. D.V. Yurasov, Yu.N. Drozdov, M.V. Shaleev,
A.V. Novikov, Features of two-dimensional to
three-dimensional growth mode transition of Ge in
SiGe/Si(001) heterostructures with strained layers
// Appl. Phys. Lett. 95, 151902 (2009).
11. T. Roch, V. Holy, A. Daniel, E. Hoflinger,
M. Meduna, T.H. Metzger, G. Bauer, J. Zhu,
K. Brunner, G. Abstreiter, X-ray studies on self-
organized wires in SiGe/Si multilayers // J. Phys.
D: Appl. Phys. 34, A6 (2001).
12. C. Tegenkamp, Vicinal surfaces for functional
nanostructures // J. Phys.: Condens. Matter, 21,
013002 (2009).
13. V. Holy, A.A. Darhuber, J. Stangl, G. Bauer,
J. Nutzeland, G. Abstreiter, Oblique roughness
replication in strained SiGe/Si multilayers // Phys.
Rev. B, 57, p. 12435 (1998).
14. M. Meduna, V. Holy, T. Roch, G. Bauer,
O.G. Schmidt, K. Eberl, X-ray reflectivity from
self-assembled structures in Ge/Si superlattices // J.
Phys. D. Appl. Phys. 34, p. A193 (2001).
15. O. Yefanov, V. Kladko, O. Gudymenko,
V. Strelchuk, Yu. Mazur, Zh. Wang, G. Salamo,
Fields of deformation anisotropy exploration in
multilayered (In,Ga)As/GaAs structures by high-
resolution X-ray scattering // Phys. Status Solidi
(a), 203, p. 154-159 (2006).
16. J. Stangl, V. Holy, G. Bauer, Structural properties
of self-organized semiconductor nanostructures //
Rev. Modern Phys., 76, p. 725 (2004).
17. V.P. Klad’ko, L.I. Datsenko, J. Bąk-Misiuk,
S.I. Olikhovskii, V.F. Machulin, I.V. Prokopenko,
V.B. Molodkin, Z.V. Maksimenko, Calculation of
two-dimensional maps of diffuse scattering by a
real crystal with microdefects and comparison of
results obtained from three-crystal diffractometry //
J. Phys. D: Appl. Phys., 34, p. A87 (2001).
18. M.Ya. Valakh, P.M. Lytvyn, A.S. Nikolenko,
V.V. Strelchuk, Z.F. Krasilnik, D.N. Lobanov,
A.V. Novikov, Gigantic uphill diffusion during
self-assembled growth of Ge quantum dots on
strained SiGe sublayers // Appl. Phys. Lett. 96,
141909 (2010).
|