J. Plasma Fusion Res. SERIES, Vol.7 (2006) 307-309

Design and Fabrication of a DC
Cylindrical Magnetron Sputtering Device
GHORANNEVISS Mahmoud1 , YASSERIAN Kiomars1,2 , ANVARI Abbas3 ,POURBALASI Hamidreza1 , HOJABRI Alireza2 and HOSSEINI Homa1
1 Plasma Physics Research center, Science and Research Branch, I.Azad University, P.O.Box 14665-678, Tehran, Iran2 Department of physics, Karaj Branch, I.Azad University, Iran3 Department of physics, Sharif University of Technology, Iran（Received: 5 October 2004 / Accepted: 8 February 2006）

Abstract
A dc cylindrical magnetron sputtering device is designed and its characteristics are studied. The device
consists of two copper cylinders with 1.5 and 5 cm in radius and 20 cm in length. A magnetic coil mounted
around the outer cylinder generates an axial magnetic field up to 550 G. The eﬀect of diﬀerent magnetic fieldon the ionization rate of the discharge is observed. It is shown that the electrical behaviour of the dischargestrongly depends on the values of the magnetic field and shows an optimum value at which the power absorbedby the plasma is maximum. The eﬀect of diﬀerent pressure on the ionization rate is also studied and the results
are reported.
Keywords:
magnetron, glow discharge, sputtering, thin film, conductance of thin film
1．Introduction
Deposition of thin films may be achieved by the following methods.
Reactive thermal evaporation deposition, RF & DC
magnetron sputtering, electron beam evaporation, ionassisted deposition techniques, electroless chemical
growth techniques, spray pyrolysis, chemical vapor deposition, vacuum evaporation and laser-assisted deposition techniques [1].
Sputtering techniques are commonly used to deposit
metal thin film on insulating and conducting substrates.
The growth parameters, such as thickness of thin film
and sputtering power usually play significant roles ingoverning the properties of metal films [2].
Plasma sources are nowadays widely used for sputtering and film deposition application [2, 3]. A dc magnetron sputtering device plasma is essentially a glow
discharge produced between two cylindrical electrodes
as anode and cathode. A magnetic coil located outside
the cylinders creates a field configuration acting as amagnetic trap for the electrons [4], which typically havea temperature of a few eV. A strong ionization source isthus produced in the region located at the front of thecathode. The ions created in this region are accelerated
towards the cathode, causing sputtering from its surface. In this paper variations of voltage and current ofa dc magnetron sputtering device for various pressuresand magnetic fields are studied and optimum values forthese parameters are obtained.
2．Experimental set up
In Fig. 1 the schematic view of the system is pre-Fig. 1 Schematic of the customized system (coaxial DCmagnetron sputtering device).
C 2006 by The Japan Society of Plasma

Science and Nuclear Fusion Research

Corresponding author’s e-mail: kyasserian@yahoo.com

307

Design and Fabrication of a DC Cylindrical Magnetron Sputtering Device

sented. As shown it consists of two coaxial cylinders
used as cathode (inner one) and anode (outer one). Diameters of the cylinders are 10 and 3 cm with 20 cm
length. The gas used in this apparatus was Argon at
the pressure of 10−2 Torr. The system was evacuatedby means of a mechanical and also a turbo-molecularpump. A high voltage power supply up to 2 kV wasused to maintain the desirable voltage across the electrodes. A nearly uniform magnetic field, parallel to theaxis of the cylinders, was generated by a coil (900 turns)
around the outer cylinder. The samples used for deposition testing were 4 × 2 cm pieces of plane glass chosen
as substrate which could be mounted on the anode asshown in Fig. 1.

testing their resistance of which the results are shown inFig. 4.
For measuring the thickness of the samples we havesupposed it is lineary related to its resistance, though weknow diﬀerent parameters should be taken into accountsuch as degree of film continuity, method of film preparation, electrode eﬀect, chemical reactivity, etc. However as we have been interested only in comparing them,
we have ignored and filtered out these parameters.
As shown the maximum thickness was obtained forthe sample produced under 190 G magnetic field corresponding to the peak power shown in Fig. 3. To in-

3．Results and discussion
The voltage between cathode and anode versus thedischarge current has been measured for various magnetic field under a constant pressure of P = 0.02 Torr.
These variations which are shown in Fig. 2 clearly
indicate that the relation between the current and voltage tends to be nonlinear for a critical value of magnetic
field, i.e. 190 G, under the above mentioned conditions.
In Fig. 3 the power absorbed by the plasma is plotted
under constant voltage (600 V) and pressure (0.02 Torr)and for diﬀerent values of magnetic field. As shown
the curve shows a peak at 190 G of magnetic field. For
testing this result, a few samples were deposited by theapparatus under equal condition but diﬀerent values ofmagnetic field, and their thicknesses were measured andcompared. For this purpose Cu was chosen as depositing material and some pieces of 2 × 4 cm glass plate as
the substrates. The thicknesses of the thin films underconstant deposition time (t = 5 min) were measured by

Fig. 3 Variation of power absorbed as a function of magnetic ﬁeld under constant voltage (600 V) andpressure (0.02 Torr).

Fig. 4 Variation of resistance of the thin ﬁlms as a function of magnetic ﬁeld under constant deposition
time (t = 5 min) and pressure (P = 0.02 Torr).

Fig. 2 Variation of voltage versus discharge current at
p = 0.02 Torr and different magnetic ﬁelds.

308

Design and Fabrication of a DC Cylindrical Magnetron Sputtering Device

Fig. 6 Variation of resistance of the thin ﬁlms as a function of pressure under constant parameters: deposition time (t = 5 min), discharge current (I = 70 mA)
and magnetic ﬁeld strength (B = 190 G).

4．Conclusion
The characteristics of a cylindrical dc magnetron
sputtering device have been studied. We have shownthat at an optimum value of the magnetic field there is a
maximum value for the power absorbed by the plasma.
At this optimum value the activity of the system is maximum which has been shown by testing the thicknessof the deposited film on a substrate. The pressure has
also shown a similar eﬀect on the deposition rate of thismagnetron sputtering device.

Fig. 5 Variation of voltage versus discharge current at
B = 190 G and different pressure.

terpret the result we note that when the magnetic field
is increased more than its optimum value, the electrons
trapped in the magnetic field cannot reach the cathodeand thus the current tends to decrease. On the contrary
when the field diminishes, it reduces the degree of ionization and thus again the discharge current decreases.
In a similar way, the eﬀect of diﬀerent pressures on
V-I curves under constant magnetic field B = 190 G areshown in Fig. 5. The eﬀect of diﬀerent pressures on
the thickness of the thin films under constant deposition
time (t = 5 min) is also shown in Fig. 6. As shown
the pressure shows an optimum value (in this case 0.02Torr) when the magnetic field strength (B = 190 G) andthe discharge current (I = 70 mA) have been kept constant.

[1]
[2]
[3]
[4]

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