The formation mechanism of modified thin-film structures based on Ge-Se(S) systems and its influence on physical properties
The mechanisms of formation of modified thin-film structures based on GeSe(S) systems with different Al, Bi, Pb, Te, In modifiers evaporated in vacuum have been determined. The process of their growth and the structure is greatly influenced by the vapor composition, energetic state of its particl...
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Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України
2007
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irk-123456789-1177752017-05-27T03:03:25Z The formation mechanism of modified thin-film structures based on Ge-Se(S) systems and its influence on physical properties Horvat, G.T. Kondratenko, O.S. Loja, V.Ju. Myholynets, I.M. Rosola, I.J. Jurkovуch, N.V. The mechanisms of formation of modified thin-film structures based on GeSe(S) systems with different Al, Bi, Pb, Te, In modifiers evaporated in vacuum have been determined. The process of their growth and the structure is greatly influenced by the vapor composition, energetic state of its particles, the velocity of condensation, the temperature of the lining and that of evaporator. The 〈Ge₀.₄S₀.₆:Х〉 (Bi,Pb,In), 〈Ge₀.₄S₀.₆:In〉 structure is characterized by the mechanism of condensation which is realized according to the type: vapor-liquid-solid phase with coalescence. The condensation mechanism in 〈Ge₀.₄S₀.₆:Al(Te)〉 structures is realized according to the type vapor-solid phase. The roughness of modified Al (2 аt. %), Bi (14 аt. %), Pb (12 аt. %), In (1 аt. %, 5 аt. %) structures is 1…13 nm, and for 〈Ge₀.₄S₀.₆:Те〉 (Те is 30.7 аt. %) structure reaches ~37 nm. The thickness and optical parameters of modified thin-film structures have been determined using the method of multiangular ellipsometry. 2007 Article The formation mechanism of modified thin-film structures based on Ge-Se(S) systems and its influence on physical properties / G.T. Horvat, O.S. Kondratenko, V.Ju. Loja, I.M. Myholynets, I.J. Rosola, N.V. Jurkovуch // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2007. — Т. 10, № 1. — С. 45-48. — Бібліогр.: 6 назв. — англ. 1560-8034 PACS 78.66.-w http://dspace.nbuv.gov.ua/handle/123456789/117775 en Semiconductor Physics Quantum Electronics & Optoelectronics Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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| language |
English |
| description |
The mechanisms of formation of modified thin-film structures based on GeSe(S)
systems with different Al, Bi, Pb, Te, In modifiers evaporated in vacuum have
been determined. The process of their growth and the structure is greatly influenced by
the vapor composition, energetic state of its particles, the velocity of condensation, the
temperature of the lining and that of evaporator. The 〈Ge₀.₄S₀.₆:Х〉 (Bi,Pb,In),
〈Ge₀.₄S₀.₆:In〉 structure is characterized by the mechanism of condensation which is
realized according to the type: vapor-liquid-solid phase with coalescence. The
condensation mechanism in 〈Ge₀.₄S₀.₆:Al(Te)〉 structures is realized according to the type
vapor-solid phase. The roughness of modified Al (2 аt. %), Bi (14 аt. %), Pb (12 аt. %),
In (1 аt. %, 5 аt. %) structures is 1…13 nm, and for 〈Ge₀.₄S₀.₆:Те〉 (Те is 30.7 аt. %)
structure reaches ~37 nm. The thickness and optical parameters of modified thin-film
structures have been determined using the method of multiangular ellipsometry. |
| format |
Article |
| author |
Horvat, G.T. Kondratenko, O.S. Loja, V.Ju. Myholynets, I.M. Rosola, I.J. Jurkovуch, N.V. |
| spellingShingle |
Horvat, G.T. Kondratenko, O.S. Loja, V.Ju. Myholynets, I.M. Rosola, I.J. Jurkovуch, N.V. The formation mechanism of modified thin-film structures based on Ge-Se(S) systems and its influence on physical properties Semiconductor Physics Quantum Electronics & Optoelectronics |
| author_facet |
Horvat, G.T. Kondratenko, O.S. Loja, V.Ju. Myholynets, I.M. Rosola, I.J. Jurkovуch, N.V. |
| author_sort |
Horvat, G.T. |
| title |
The formation mechanism of modified thin-film structures based on Ge-Se(S) systems and its influence on physical properties |
| title_short |
The formation mechanism of modified thin-film structures based on Ge-Se(S) systems and its influence on physical properties |
| title_full |
The formation mechanism of modified thin-film structures based on Ge-Se(S) systems and its influence on physical properties |
| title_fullStr |
The formation mechanism of modified thin-film structures based on Ge-Se(S) systems and its influence on physical properties |
| title_full_unstemmed |
The formation mechanism of modified thin-film structures based on Ge-Se(S) systems and its influence on physical properties |
| title_sort |
formation mechanism of modified thin-film structures based on ge-se(s) systems and its influence on physical properties |
| publisher |
Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
| publishDate |
2007 |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/117775 |
| citation_txt |
The formation mechanism of modified thin-film structures based on Ge-Se(S) systems and its influence on physical properties / G.T. Horvat, O.S. Kondratenko, V.Ju. Loja, I.M. Myholynets, I.J. Rosola, N.V. Jurkovуch // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2007. — Т. 10, № 1. — С. 45-48. — Бібліогр.: 6 назв. — англ. |
| series |
Semiconductor Physics Quantum Electronics & Optoelectronics |
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Semiconductor Physics, Quantum Electronics & Optoelectronics, 2007. V. 10, N 1. P. 45-48.
© 2007, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
45
PACS 78.66.-w
The formation mechanism of modified thin-film structures
based on Ge-Se(S) systems and its influence on physical properties
G.T. Horvat1, O.S. Kondratenko2, V.Ju. Loja2, I.M. Myholynets1, I.J. Rosola1, N.V. Jurkovуch1
1Uzhgorod National University, 54, Voloshyna str., 88000 Uzhgorod, Transcarpathia, Ukraine
E-mail: horvathalina@mail.ru
2V. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine
3Institute of Electronic Physics, NAS of Ukraine
Abstract. The mechanisms of formation of modified thin-film structures based on Ge-
Se(S) systems with different Al, Bi, Pb, Te, In modifiers evaporated in vacuum have
been determined. The process of their growth and the structure is greatly influenced by
the vapor composition, energetic state of its particles, the velocity of condensation, the
temperature of the lining and that of evaporator. The 〈Ge0.4S0.6:Х〉 (Bi,Pb,In),
〈Ge0.4Se0.6:In〉 structure is characterized by the mechanism of condensation which is
realized according to the type: vapor-liquid-solid phase with coalescence. The
condensation mechanism in 〈Ge0.4S0.6:Al(Te)〉 structures is realized according to the type
vapor-solid phase. The roughness of modified Al (2 аt. %), Bi (14 аt. %), Pb (12 аt. %),
In (1 аt. %, 5 аt. %) structures is 1…13 nm, and for 〈Ge0.4S0.6:Те〉 (Те is 30.7 аt. %)
structure reaches ~37 nm. The thickness and optical parameters of modified thin-film
structures have been determined using the method of multiangular ellipsometry.
Keywords: modified thin-film structures, condensation mechanism, surface morphology,
optical parameters.
Manuscript received 26.10.06; accepted for publication 26.03.07; published online 01.06.07.
1. Introduction
Thin films with the micron thickness may differ
substantially by their properties from massive samples. It
opens the opportunity to create materials, which are new
both by their structure and properties. Using them, the
practical realization of nanocrystalline state becomes
possible. This fact is very important for thin-film
electronics, optics and sensorics.
Nowadays, there exist a great number of formation
methods of gradient structures with the necessary
profiles of modifier distribution. These methods include
thermal rectification of multicomponent alloys, different
kinds of ionic evaporation, epitaxy, alloying, as well as
the methods of simultaneous evaporation of components
from two and more evaporators. The choice of the
method to obtain gradient structures is conditioned by a
specific task and available technological means. The
forecast of film peculiarities is conditioned not only by
its very small size, but by the correct choice of modifier
element, enabling the creation of structures with the
target properties. This article highlights the mechanisms
of formation of modified thin-film structures based on
Ge-Se(S) systems with different modifiers as well as
their influence on physical properties.
2. The regularities of film evaporation and
condensation
While analysing the process of surface coating formation
on lining one should single out two aspects: the physical
and technological ones [1]. The physical aspect consists
of formation regularities of initial surface layers, the
character of longitudinal and transverse structures,
surface relief, etc. The process of condensation and the
structure of the film formed depend upon the kinetic
parameters of condensation, temperature and the
potential relief of the lining, the density of the falling
molecular beam, the character of evaporating atoms
interaction. The most important is the temperature of the
lining. The molecular beam condenses on it in the case
when the temperature of the lining is lower than some
critical one.
As far as the technological aspect is concerned, two
mechanisms of condensation are realized: vapor-solid
phase and vapor-liquid-solid phase [1]. These conden-
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2007. V. 10, N 1. P. 45-48.
© 2007, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
46
Fig. 2. Morphology of the gradient film Ge0.4S0.6 surface.
sation mechanisms determine different ways of film
formation and their growth from the vapor phase,
influencing the film properties. It is necessary to
mention that the mechanism of condensation depends
upon the correlation of temperature of lining and that of
melting, at which the substance being condensed. With
the change of lining temperature, it is possible to change
the mechanism of condensation. With the condensation
of molecular beams of complex composition, the
mechanism of condensation depends on the composition
of vapor phase as well. After finishing the formation of
the whole layer, the regularities of the film growth are
determined not only by the mechanism of substance
condensation, but mainly by the structure of the initially
formed layers.
In the process of obtaining the gradient films on the
basis of glass-like Ge0.4Se(S)0.6 with Al, Bi, Pb, Te, In
modifiers the method of thermal evaporation in vacuum
from two separate evaporators has been used [2]. The
necessary flow of the modifying component has been
created due to the change of evaporation temperature. The
control of chemical and quantitative composition of
gradient films being obtained has been conducted by the
method of mass spectrometry of post-ionized neutral
particles. The thickness of films was from 0.45 to 2.7 nm.
3. The investigation of film surface
The investigation of microrelief peculiarities of gradient
films has been performed using an atomic force
microscope (AFM) Dimension TM 3000. The measure-
ments have been made in air at the room temperature
using the nib made of silicon; with radius of curvature
~5-10 nm on a string console element with the
coefficient of rigidity 0.01-0.6 N/m. The geometry of the
nib and its interaction with the surface under
investigation limited the resolution of horizontal
dimension to 2 nm and of vertical ones to 0.1 nm [3].
Figs. 1-3 depict the morphology of the surfaces of
〈Ge0.4Se(S)0.6:In〉 heterogeneous films. It is complicated
enough and depends upon the type of matrix and the
type of the modifier that was introduced.
It has been found that while doping with Bi, Pb, In
modifiers the formation of condensate is carried out
according to the type vapor-liquid-solid phase with
coalescence. Condensed atoms interact between
themselves stronger than with the surface of the neutral
lining. This is the explanation of their free and intensive
migration along the surface. With the high density of the
flow of the substance being evaporated, the nuclei of
crystal or liquid phase are formed. The surface of the
structure with such a mechanism of condensation is
characterized by the formation of canals and merging
small islands into the larger ones. Table 1 demonstrates
the basic parameters that characterize the surface of the
films. The height of the outgrowth of Bi gradient
structure varies from 0.4 to 2.5 nm, while that for Pb
gradient structures varies from 1.2 to 5.4 nm [4].
Fig. 1. Section analysis of Ge0.4S0.6:In gradient film surface.
It has been found that the increase of the In
concentration (from 1 to 5 at. %) in Se-based structure
does not lead to significant changes in surface
morphology. The roughness of their surfaces
approximates the one of the very matrix (about 0.5 nm).
The height of the roughness is: 0.5…1.3 nm when In is
1 at. % and 0.5…2.13 nm when In is 5 at. %.
〈Ge0.4S0.6:In〉 (5 аt. % In) film is characterized by
the vapor-liquid-solid phase type of condensation. But in
contrast to the chaoticity of island structure of the Se
film surface (Fig. 2), it is characterized by the partial
inputting of comparatively big islands (Fig. 3). The
height of unevenness of the gradient structure surface
varies from 0.8 to 13.6 nm.
When the forces of interaction between substance
molecules being condensed are less than the forces of
their bonds with the lining, the influence of kinetic
parameters of the lining on the process of film formation
according to the vapor-solid phase mechanism rises
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2007. V. 10, N 1. P. 45-48.
© 2007, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
47
sharply. Such a mechanism of condensation of the
substance being evaporated is characteristic of
〈Ge0.4S0.6:Х〉 (Х is Te, Al) films. For 〈Ge0.4S0.6:Al〉 (Al is
2 аt.%) structure, it has been established that the
condensate formation is carried out accompanied by
dense filling with islands of smaller sizes (1.2…5.4 nm).
This process is not observed in structures with In, Bi, Pb
modifiers. In contrast to former results for 〈Ge0.4S0.6:Те〉
(Те is 30.7 аt. %) film, parameters characterizing the
roughness value differ considerably. Such a difference in
value for the structures with Te is explained by the
availability of two chalcogenides with two different
parameters. Due to this fact, the intersubstitution of S by
Te is possible. It leads to the partial disordering of the
amorphous matrix framework based on glass-like
Ge0.4S0.6, to formation of solid solutions with the target
concentrations according to the vapor-solid phase mecha-
nism of condensates with the formation of a considerable
number of large islands. The island height reaches 37 nm.
As it is seen from the figures, the surface roughness of the
films under investigation is insufficient, and varies within
the limits of 1 to 13 nm when the structure thickness is
between 500 to 3000 nm. Only in the case of Te the
roughness thickness reaches 37 nm, which means that the
surfaces of films are smooth enough.
The main peculiarity of obtaining the amorphous
gradient structures with the modifiers in a solid phase
lies in the fact that they are always formed under
unbalanced conditions, when the maximum of potential
energy of the system is not reached. High energy of
amorphous state influences first of all the ways of
packing the structural units of solid substance, which are
numerous in this case.
Table 1. Basic parameters characterizing film surfaces.
Composition
RMS
(mean
vertical
quadratic
devia-
tion), nm
Ra (mean
arithme-
tical
deviation),
nm
Rmax
(maxi-
mum
devia-
tion), nm
Uneven-
ness
height,
nm
Ge0.4S0.6 0.67 0.5 2.40 0.3−0.5
〈Ge0.4S0.6:Bi〉
(14 аt.%) 0.80 0.22 3.34 0.4−2.5
〈Ge0.4S0.6:Те〉
(30 аt.%) 6.93 5.45 21.84 2.3−36.9
〈Ge0.4S0.6:Al〉
(2 аt.%) 1.53 1.03 8.07 1.4−6.3
〈Ge0.4S0.6:Pb〉
(12 аt.%) 2.44 2.06 11.06 1.2−5.4
〈Ge0.4S0.6:In〉
(5 аt.%) 3.23 2.41 8.83 0.8−13.6
Ge0.4Se0.6 1.78 0.26 1.06 0.2−0.5
〈Ge0.4Se0.6:In〉
(1 аt.%) 2.26 0.7 2.93 0.5−1.3
〈Ge0.4Se0.6:In〉
(5 аt.%) 0.72 0.59 2.29 0.5−2.13
Fig. 3. Morphology of the gradient film 〈Ge0.4S0.6:In〉
(5 аt.% In) surface.
One of the most perspective methods of thin films
investigation, which helps to obtain information
concerning the purity of the surface and the
heterogeneity of the structure, is ellipsometry. Its
methods are contactless, not influencing the properties
and allow to define both the optical contacts and film
thickness. The procedure of ellipsometry is based on
working out the direct and reversed problems of
ellipsometry. The measured ellipsometric angles for a
given structure with the known optical peculiarities and
geometric sizes are calculated within the limits of the
direct problem. The reversed problem uses angles ∆ and
Ψ, measured using an ellipsometer to reveal unknown
optical parameters of the system under investigation [5].
Multiangular ellipsometric measurements have been
carried out according to a null procedure on the basis of
the ellipsometer ЛЭФ-3М-1 [6]. The working
wavelength (λ) is equivalent to 632.8nm and the angular
range of light incidence (φ) is equivalent to 45-80° .
Having used angles ∆ and Ψ measured using the
ellipsometer in order to find unknown optical parameters
of the system under investigation, the optical parameters
of films have been calculated (Table 2).
Table 2. Optical parameters of films (λ = 0.6328 µm).
Composition Refraction
index,
n
Reflection
coefficient,
k
Film
thickness
d, nm
Ge0.4S0.6 2.131 0.011 1000.04
〈Ge0.4S0.6:In〉
(5 аt.%)
2.429 0.011 1001.49
〈Ge0.4Se0.6:In〉
(1 аt.%)
2.361 0.028 1147.66
〈Ge0.4Se0.6:In〉
(5 аt.%)
2.350 0.013 999.98
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2007. V. 10, N 1. P. 45-48.
© 2007, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
48
As it is seen from the table, inputting the modifier
into the matrix Ge0.4S0.6 leads to the increase of the
refraction index, while to Ge0.4Se0.6 matrix to its
decrease. Thicknesses of films calculated applying the
ellipsometric method almost coincide with those targeted
beforehand during evaporating. High accuracy of the
ellipsometric method is connected with the fact that the
state of light polarization reacts greatly even on/at very
slight changes of the state of reflecting surface that is on
the availability of different intermediate layers,
preconditioned by the interaction of the surface with the
environment weather or other inner processes.
4. Conclusions
As one can see from what has been written above, the
process of growth and the structure of amorphous
condensates of heterogeneous modified structures, being
evaporated in vacuum, is greatly influenced by the vapor
composition, energetic state of its particles, the velocity
of condensation, temperature of the lining and that of
evaporator. Having analyzed the results of the
investigation of the surface morphology of
〈Ge0.4Se(S)0.6:Х〉 (Х – Al, Bi, Pb, Te, In) structures, the
mechanisms of their formation have been established.
The structure 〈Ge0.4S0.6:Х〉 (Bi, Pb, In), 〈Ge0.4Se0.6:In〉 is
characterized by the mechanism of condensation which
is carried out according to the type: vapor-liquid-solid
phase with coalescence. The increase of the In
concentration does not change significantly the surface
morphology of the structure based on S, partial ordering
of insular surface structure is carried out. Further
investigation of the given structures with other In
contents in them is of great interest. The condensation
mechanism in 〈Ge0.4S0.6:Al(Te)〉 structures is realized
according to the vapor-solid phase type. The roughness
of modified Al (2 аt.%), Bi (14 аt. %), Pb (12 аt. %),
In(1 аt. %, 5 аt. %) structures is 1…13 nm, and for
〈Ge0.4S0.6:Те〉(Те is 30.7 аt. %) structure reaches ~37 nm.
The thickness and optical parameters of modified thin-
film structures have been determined by the method of
multiangular ellipsometry.
Acknowledgments
The authors express their sincere gratitude to
O.S. Lytvyn for her assistance in investigations of the
structures by using AFM.
References
1. Yu.M. Tairov, V.F. Tsvetkov, Technology of
semiconductor and dielectric materials. Vysshaya
shkola, Moscow, 1990 (in Russian).
2. N.V. Yurkovich, A.V. Lada, V.Yu. Loya, I.M. Mi-
golinets, S.S. Krafchik, O.I. Pagulich, Peculiarities
of obtaining inhomogeneous structures Ge2S3+Al
(Bi, Pb, Te) with a preliminary set of component
distribution // Collection of reports of the 14-th
Intern. Symposium “Thin films in optics and
electronics”. – Kharkov, Published by Kharkov
Physico-Technical Institute, 2002, p. 138-139 (in
Russian).
3. Nanoscope. Command reference manual. – Digital
Instruments, Santa Barbara, CA, 1999.
4. N.V. Yurkovich, Modelling and physical properties
of modified structures based on vitreous germa-
nium chalcogenides. Author’s abstract of the
candidate degree thesis (Phys.-math. sci.),
Uzhgorod, 2004 (in Russian).
5. L.A. Zabashta, Investigations of optical properties
of structures semiconductor – surface phase by
using the method of multiangular ellipsometry.
Author’s abstract of the candidate degree thesis
(Phys.-math. sci.), Sumy, 1996 (in Russian).
6. I.A. Shaikevich, P.I. Drozd, L.V. Poperenko,
A small-size goniometer-ellipsometer and its
application to studies of rough surface //
Zavodskaya laboratoriya No 7, p. 35-36 (1985) (in
Russian).
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