Features of high-current pulsed regimes in regimes in magnetron sputtering systems
The high-current pulsed magnetron sputtering system is presented and its operation regimes are studied. The comparative technological trials of the system are carried out at various types of the discharge: stationary magnetron, pulsed magnetron and pulsed arc. A procedure of calculation of dynamics...
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2005
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| Цитувати: | Features of high-current pulsed regimes in regimes in magnetron sputtering systems / A.A. Bizyukov, A.Ye. Kashaba, E.V. Romashchenko, K.N. Sereda, I.K. Tarasov, S.N. Abolmasov // Вопросы атомной науки и техники. — 2005. — № 2. — С. 167-169. — Бібліогр.: 4 назв. — англ. |
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irk-123456789-798092015-04-05T03:02:13Z Features of high-current pulsed regimes in regimes in magnetron sputtering systems Bizyukov, A.A. Kashaba, A.Ye. Romashchenko, E.V. Sereda, K.N. Tarasov, I.K. Abolmasov, S.N. Low temperature plasma and plasma technologies The high-current pulsed magnetron sputtering system is presented and its operation regimes are studied. The comparative technological trials of the system are carried out at various types of the discharge: stationary magnetron, pulsed magnetron and pulsed arc. A procedure of calculation of dynamics and distribution of temperature in a near surface layer of the target material at heat application to a surface in conditions of low pressures of working gases is described. Описана сильнострумова імпульсна магнетронна розпилювальна система та вивчені режими її роботи. Проведені порівняльні технологічні випробування системи при різних типах розряду: стаціонарному магнетронному, імпульсному магнетронному та імпульсному дуговому. Приведена методика розрахунку динаміки і розподілу температури в приповерхневому шарі матеріалу мішені при підводі тепла до поверхні в умовах низьких тисків робочих газів. Представлена сильноточная импульсная магнетронная распылительная система и изучены режимы ее работы. Проведены сравнительные технологические испытания системы при различных типах разряда: стационарном магнетронном, импульсном магнетронном и импульсном дуговом. Приведена методика вычисления динамики и распределения температуры в приповерхностном слое материала мишени при подводе тепла к поверхности в условиях низких давлений рабочих газов. 2005 Article Features of high-current pulsed regimes in regimes in magnetron sputtering systems / A.A. Bizyukov, A.Ye. Kashaba, E.V. Romashchenko, K.N. Sereda, I.K. Tarasov, S.N. Abolmasov // Вопросы атомной науки и техники. — 2005. — № 2. — С. 167-169. — Бібліогр.: 4 назв. — англ. 1562-6016 PACS: 52.40.Hf http://dspace.nbuv.gov.ua/handle/123456789/79809 en Вопросы атомной науки и техники Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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Low temperature plasma and plasma technologies Low temperature plasma and plasma technologies |
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Low temperature plasma and plasma technologies Low temperature plasma and plasma technologies Bizyukov, A.A. Kashaba, A.Ye. Romashchenko, E.V. Sereda, K.N. Tarasov, I.K. Abolmasov, S.N. Features of high-current pulsed regimes in regimes in magnetron sputtering systems Вопросы атомной науки и техники |
| description |
The high-current pulsed magnetron sputtering system is presented and its operation regimes are studied. The comparative technological trials of the system are carried out at various types of the discharge: stationary magnetron, pulsed magnetron and pulsed arc. A procedure of calculation of dynamics and distribution of temperature in a near surface layer of the target material at heat application to a surface in conditions of low pressures of working gases is described. |
| format |
Article |
| author |
Bizyukov, A.A. Kashaba, A.Ye. Romashchenko, E.V. Sereda, K.N. Tarasov, I.K. Abolmasov, S.N. |
| author_facet |
Bizyukov, A.A. Kashaba, A.Ye. Romashchenko, E.V. Sereda, K.N. Tarasov, I.K. Abolmasov, S.N. |
| author_sort |
Bizyukov, A.A. |
| title |
Features of high-current pulsed regimes in regimes in magnetron sputtering systems |
| title_short |
Features of high-current pulsed regimes in regimes in magnetron sputtering systems |
| title_full |
Features of high-current pulsed regimes in regimes in magnetron sputtering systems |
| title_fullStr |
Features of high-current pulsed regimes in regimes in magnetron sputtering systems |
| title_full_unstemmed |
Features of high-current pulsed regimes in regimes in magnetron sputtering systems |
| title_sort |
features of high-current pulsed regimes in regimes in magnetron sputtering systems |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
2005 |
| topic_facet |
Low temperature plasma and plasma technologies |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/79809 |
| citation_txt |
Features of high-current pulsed regimes in regimes in magnetron sputtering systems / A.A. Bizyukov, A.Ye. Kashaba, E.V. Romashchenko, K.N. Sereda, I.K. Tarasov, S.N. Abolmasov // Вопросы атомной науки и техники. — 2005. — № 2. — С. 167-169. — Бібліогр.: 4 назв. — англ. |
| series |
Вопросы атомной науки и техники |
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2025-07-06T03:46:56Z |
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| fulltext |
FEATURES OF HIGH-CURRENT PULSED REGIMES IN MAGNETRON
SPUTTERING SYSTEMS
A.A. Bizyukov, A.Ye. Kashaba, E.V. Romashchenko*, K.N. Sereda, I.K. Tarasov**,
S.N. Abolmasov***
V.N. Karazin Kharkov National University, Kharkov, Ukraine;
* East-Ukrainian National University, Lugansk, Ukraine;
** NSC Kharkov Institute of Physics and Technologies, Kharkov, Ukraine;
*** Kyoto University, Japan
The high-current pulsed magnetron sputtering system is presented and its operation regimes are studied. The
comparative technological trials of the system are carried out at various types of the discharge: stationary magnetron,
pulsed magnetron and pulsed arc. A procedure of calculation of dynamics and distribution of temperature in a near
surface layer of the target material at heat application to a surface in conditions of low pressures of working gases is
described.
PACS: 52.40.Hf
1. INTRODUCTION
The investigation of the pulsed magnetron sputtering
system (MSS) in modes with large discharge currents is
stimulated by an opportunity to decrease energy expenses
on the process of ion sputtering at large densities of ion
current to the target when transition of ion-nuclear inter
action into a mode of "thermal peaks" occurs [1-4]. The
realization of these opportunities of pulsed conditions of
the MSS is especially attractive at use of conventional
discharge systems and power units for a dc MSS. At the
same time, the modes of operations of the MSS with large
densities of ion current to the sputtered target are accom
panied by processes of intensive heating of a target sur
face that can lead to transition into the mode of "thermal
peaks", and to thermal explosion of microroughnesses of
the surface or even to melting of a target material.
In the presented work the high-current pulsed MSS is
submitted and the modes its operation are studied. The
comparative technological trials of the system are carried
out at various types of the discharge: stationary mag
netron, pulsed magnetron and pulsed arc. In the presented
work a procedure of calculation of dynamics and distribu
tion of temperature in a near surface layer of the material
also is given at heat application to a surface in conditions
of low pressures of working gases.
2. MATERIALS AND METHODS
The experiments on study of pulsed conditions of the
MSS were carried out on conventional planar magnetron
with a target diameter of 150 mm (copper). Intensity of a
magnetic field on a surface of a target was about
H=250 Oe . The anode of the magnetron was
grounded and the negative voltage from a conventional
magnetron power unit was applied to the target: a dis
charge voltage up to 1000 V , discharge current up to
5 А in a range of pressures of
p=1 ÷8 ⋅10−3 Тorr (working gas - argon).
At investigation of pulsed conditions of the MSS be
tween a power unit and magnetron the store of energy
(pulsed capacitor with a capacity of 10÷100 μF ) and
thyristor circuit changer-transformer was included. The
circuit changer-transformer provided delivery of negative
impulses of a voltage U=1 ÷3 kV to the target with
duration of 50÷200 μs and frequency of 50 Hz
and adjustment of a discharge current in a range of
20÷5000 А .
3. RESULTS OF EXPERIMENTS AND
DISCUSSION
The pulsed magnetron discharge, in contrast to sta
tionary, stably develops at much lower pressures of work
ing gas. The limiting pressure of the discharge ignition in
stationary conditions was 2 ⋅10−3 Torr , in pulsed -
3 ⋅10−4 Torr . The current-voltage characteristics and
the discharge parameters are typical for the magnetron
discharge. In this mode of operation of the MSS, in spite
of the facts that the current of the discharge exceeds aver
age current of a cathode spot for a copper electrode (75 А)
and the duration of existence of the discharge is sufficient
for occurrence of a cathode spot, the transition into an arc
mode does not occur. When the discharge current exceeds
some critical value in a range of 80÷120 А , we can
observe formation of cathode spots on the target surface.
The apparent phenomena, probably, are related to a break
down of an external magnetic field of the magnetron by
own magnetic field of a drift (Hall) electron current. In
the Fig.1, the schematic figure of analytical model of cir
cular planar magnetron is given. Owing to axial symmetry
the zx-plane with radius of the magnetron loop of 5 cm is
considered only.
In Fig.2, the results of numerical modelling of super
position of own external magnetic field of the planar mag
netron with value on the target surface of В=200 Oe
and magnetic field created by a Hall current with a value
of I d=80 А is shown.
The field inside the section of a conductor was calcu
lated from the theory about circulation of magnetic inten
sity, and outside of section of a conductor by means of
vector potential (elliptic integrals of 1-st and 2-nd sort).
One can see that at large currents the configuration of
Problems of Atomic Science and Technology. Series: Plasma Physics (11). 2005. № 2. P. 167-169 167
magnetic field loses confining properties and the dis
charge transfers from the discharge with cross magnetic
field into the discharge with longitudinal magnetic field.
Fig.1. Schematic of analytical model of circular planar
magnetron
HFig.2. Change of topography of magnetic surfaces of the
MSS in the region of magnetic trap
The technological trials have shown that the deposition
rate of coatings depends on the discharge type in the MSS
and this dependence in pulsed conditions is stronger than
in stationary ones. At average power of 3 kW and peak
pulsed currents for each type of the discharge the deposi
tion rate of a copper in the pulsed magnetron discharge
was incremented in 1 . 2 ÷1 . 3 times, in pulsed arc -
in 3 ÷3 .5 times. The mechanical and adhesive char
acteristics of coatings were also improved.
Increase of velocity of mass transfer at pulsed high-
current operation mode of the MSS probably is connected
with transition of an ion sputtering into a mode of "ther
mal peaks" when the discharge current reaches values
typical for an electric arc, but the transition into an elec
tric arc and occurrence of cathode spots does not occur.
At pulsed conditions of operation of the MSS heating
of a surface layer of a material of a sputtered target
occurs. During period between impulses the processes of
cooling occurs. For evaluation of dynamics of distribution
of temperature in a near surface layer, we shall take the
equation of a thermal conduction:
∂T
∂ t
=a 2 ∂
2 T
∂ x2 ,
where a2=k /cρ is the thermal diffusivity of the target
material, T is the temperature in a selected point of the
material, с is the specific heat capacity, ρ is the density of
the target material, k is the thermal conductivity.
The boundary and initial conditions for the equation of
a thermal conduction for alternating periods of heating
and cooling of the surface have a various looks. Therefore
for the analytical solution of the problem on distribution
of temperature in a near surface layer of the target it is
necessary to divide the problem on two parts. One part
describes the process of heating of the surface during one
impulse, and second part describes the process of cooling
of the surface between impulses:
1)
∂T 1
∂ t
=a2 ∂
2 T 1
∂ x2
, k
∂T 1 L ,t
∂ x
=−q t ,
k
∂T 1 0, t
∂ x
=0 , T 1 x ,0 =T 0 , where
q t =4Q t / τ−t 2 /τ 2 is the parabolic shape pulse,
τ is the pulse duration, L is the thickness of near surface
layer.
2)
∂T 2
∂ t
=a2 ∂
2 T 2
∂ x2
,
∂T 2 L , t
∂ x
=hT L ,t ,
T 2 0, t =0 with initial conditions corresponding
T 1 x , τ .
Using cosine-transformation Fourier it is possible to
obtaine the following solution describing spatial-temporal
distribution of temperature in near surface layer of target
with thickness L during her heating:
T 1 x , t =4 Qa2
kL τ {− t3
3τ
t2
2
2 ∑
n=1
∞
−1 n cos π nx
L
⋅¿
¿⋅[ exp−a2π 2 n2 t
L2 −2L6
τa6 π6 n6
L4
a4π 4 n4
L2 2L4−2a2 π2 n2 L2 ta4 π4 n4 t2
τa6 π6 n6
L2 −L2a2π 2 n2 t2
a4 π4 n4 ]}T 0 .
At the time of t=τ we shall obtain expression for spa
tial distribution of temperature in the layer after heating:
T 1 x , τ =4 Qa2
kL τ {τ 2
6
2 ∑
n=1
∞
−1 n An cos π nx
L }T 0 ,
where
An=exp−a2 π 2n2τ
L2 −2L6
τa6 π6 n6
L4
a 4π 4 n4
L2 2L4−2a2π 2 n2 L2 τa4 π 4n4 τ2
τa6π6 n6
L2 −L2a2π 2 n2 τ2
a4 π4 n4
168
Using a method of partitioning variable Fourier it is possi
ble to obtain the following solution for the problem which
describes cooling of the surface between impulses
T 2 x , t =2
L2 {∑m=1
∞
[ 2 Qa2 τ
3k
L1 −cos λm
λm
T 0 L 1 −cos λm
λm
8 Qa2
kτ ∑
n=1
∞
−1 n An⋅
¿∫
0
L
cosπ nx
L
sin λm dx ]⋅sin λm xexp−a2 λm
2 t
L2 }.
The natural numbers λm are obtained by graphical cal
culation from the trigonometric equation λ=htg λL .
0
0.0002
0.0004
0
0.005
0.01
0.015
0.02
0
2
4
6
0
0.0002
0.0004
0
2
4
6
Fig.3. Spatial - temporal distribution of temperature in a
copper target of magnetron sputter system
In Fig.3 the spatial-temporal distribution of tempera
ture in the near surface layer of the target with thickness
of L=0 . 5 mm is shown at a pulsed heating (the
pulse duration is τ=100 μs , the density of applied
power is Q=6 ⋅106 W /m2 ) and subsequent cooling
of the target during the time period of 0.02 s correspond
ing to repetition rate of impulses 50 Hz.
The average temperature of a surface and volume
grows linearly with time, however the pulsed temperature
of a surface can essentially exceed the temperature of vol
ume. In the gaps between impulses partial cooling of the
surface due to heat exchange to environmental gas and
propagation of a thermal wave deep into the target occurs.
The calculations show that at the pulsed high-current
magnetron discharge the temperature of the copper target
surface grows in 2-3 times, but does not reach the value
of melting temperature that proves by experimental data.
At the same time, essential increase of the discharge cur
rent and deposition rates of coating in this mode testify to
growth of velocity of mass transfer as a result of transi
tion from an ion - atom sputtering of the target to a mode
of "thermal peaks".
4. CONCLUSIONS
Thus, the transition from stationary to pulsed opera
tion of a conventional magnetron sputtering system
(MSS) has allowed to obtain universal technological sys
tem (stationary magnetron - pulsed high-current mag
netron with enhanced deposition rate - arc evaporator)
with increased density of pulsed reactionary plasma. It is
theoretically shown that the transition to an arc mode oc
curs as a result of deformation of configuration of mag
netic trap and loss of confining properties of the trap
when the discharge current exceeds the critical value. The
scheme of calculation of temperature distribution in the
sputtered target at pulsed thermal action on a surface is
proposed that significally simplifies a choice of optimum
parameters for various vacuum-plasma surface process
ing.
REFERENCES
1. B.S. Danilin. Application of low-temperature plasma
for deposition of thin films. M.: “Energoatomizdat”,
1989, p. 328.
2. V.P. Belevsky, A.I. Kuzmichov, et al. Pulsing ion
treatment and deposition of thin films and coats. К.:
Society “Znaniye” of Ukraine, 1991, p. 23.
3. A.I. Kuzmichov. Modulators for pulsing feed of mag
netron sputtering systems // Proc. 7th International
Symposium “Thin films in electronics”, Ioshkar-Ola.
1996, p.237 - 240.
4. P. Berish. Sputtering of solid bodies by ion bombard
ment. M.: "Mir", 1984, p. 336.
ОСОБЕННОСТИ СИЛЬНОТОЧНЫХ ИМПУЛЬСНЫХ РЕЖИМОВ В МАГНЕТРОННЫХ
РАСПЫЛИТЕЛЬНЫХ СИСТЕМАХ
А.А. Бизюков, А.Е. Кашаба, Е.В. Ромащенко, К.Н. Середа, И.К. Тарасов, С.Н. Аболмасов
Представлена сильноточная импульсная магнетронная распылительная система и изучены режимы ее работы.
Проведены сравнительные технологические испытания системы при различных типах разряда: стационарном
магнетронном, импульсном магнетронном и импульсном дуговом. Приведена методика вычисления динамики
и распределения температуры в приповерхностном слое материала мишени при подводе тепла к поверхности в
условиях низких давлений рабочих газов.
ОСОБЛИВОСТІ ПОТУЖНОСТРУМОВИХ ІМПУЛЬСНИХ РЕЖИМІВ У МАГНЕТРОННИХ РОЗПИ
ЛЮВАЛЬНИХ СИСТЕМАХ
О.А. Бізюков, А.Є. Кашаба, О.В. Ромащенко, К.М. Середа, І.К. Тарасов, С.М. Аболмасов
169
x, m
t, s
T, a.u.
Описана сильнострумова імпульсна магнетронна розпилювальна система та вивчені режими її роботи.
Проведені порівняльні технологічні випробування системи при різних типах розряду: стаціонарному
магнетронному, імпульсному магнетронному та імпульсному дуговому. Приведена методика розрахунку ди
наміки і розподілу температури в приповерхневому шарі матеріалу мішені при підводі тепла до поверхні в
умовах низьких тисків робочих газів.
170
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