MINISTRY OF EDUCATION AND SCIENCE OF RUSSIA
Federal State Autonomous Educational Institution of Higher Education
"National Research University "Moscow Institute of Electronic Technology"
Institute of Nano- and Microsystem Technology
REPORT on laboratory work
in direction 11.03.03 "Design and technology of electronic means"
Profile: "Electronic means of robotic devices and systems"
On the topic of: "Investigation of current-voltage characteristics of magnetron sputtering
devices".
Checked by teacher
Moscow 2021
Objective:
1) To study the process of plasma formation in magnetron sputtering devices (MRU);
2) Conduct theoretical and experimental studies of the influence of various factors on the
CVC of a magnetron discharge;
To perform the work, a vacuum installation is used, equipped with the following
equipment and instruments:

MRU with electromagnetic system;

MRU power supply;

MRU solenoid power supply;

working gas supply unit;

vacuum gauge;

magnetic induction meter type Sh1-8
1 Brief theoretical information about the system under study
The investigated MRS, the design of which is shown in Figure 1, refers to systems with a
planar target and an annular spray zone. The main unit of the MRS is the cathode block, which
consists of a copper water-cooled body placed between the poles of the magnetic circuit, fixed on
the flange. The sputtered annular target is installed in the annular groove of the body, which
ensures good thermal and electrical contact during the sputtering process due to the thermal
expansion of the target. The target is intensively cooled by running water circulating through a
channel in the cathode block housing located directly under the target sputtering zone.
An electromagnet is installed under the body, which creates an adjustable magnetic field
of a given value above the target surface. The geometry of the magnetic field, determined by the
configuration of the lines of force, is formed by annular pole pieces raised above the target
surface. This design of the magnetic system makes it possible to create a sufficiently strong
magnetic field near the target surface, which does not depend on the thickness of the target used.
The cathode block is attached to the working chamber through the insulator with a flange.
A water-cooled anode is installed on the same insulator. The anode and cathode blocks on the
side of the chamber are covered with a screen that eliminates electrical breakdowns on the body
of the working chamber. The regulated voltage between the body of the cathode block and the
anode is supplied from a DC power supply.
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Figure 1 - Scheme of the design of the investigated MPS.
1 - body of the cathode block; 2 - target; 3 - anode; 4 - electromagnet; 5 - magnetic circuit; 6, 7 pole pieces; 8 - magnetic field line; 9 - screen; 10 - insulator; 11 - flange; 12 - MRU power
supply; 13 - electromagnet power supply.
The most important unit of the MRS is the magnetic system, which forms a region of highintensity plasma near the target surface. The magnetic system should create a strong (up to 500800 G) magnetic field, the lines of force of which should be closed above the surface of the
sputtered target, generally forming arcs, the upper point of which is located above the center of
the target sputtering zone. Violation of this requirement for the standard design scheme of the
MSS leads to a deterioration in the conditions of plasma localization and discharge parameters, a
shift in the sputtering zone from the working part of the target, and a decrease in the material
utilization factor (CMM).
The choice of the anode position is important for ensuring the high efficiency of MRS
operation. The anode must be located outside the magnetic trap and at such a distance from the
center of the sputtering zone that there is no effective capture by the anode of high-energy
electrons cycling along the sputtering zone of the target.
Main parameters of MRU

Electrode voltage (300-800 V in DC mode)

Current density and discharge current (up to 100 mA/cm2 or more)

Specific power on the target (up to 50 W/cm2 and more)

The value of the magnetic field induction (300 - 1000 gauss)

Operating pressure (0.05 - 1 Pa)
Limiting current density (sputtering rate) depends on the magnitude and configuration of
the magnetic field, operating pressure, sputtered material and cooling conditions of the sputtered
target
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2 Practical part
Influence of argon pressure and magnetic field
(planar aluminum target)
рр = 0.03 Pa
B=0.03 T
Explanation:
The CVC is influenced by the induction of the magnetic field and the operating pressure.
On the left, the influence of the working pressure is significant. A decrease in its value correlates
with high operating voltages and acquires linear features. The reason for such indicators is a
decrease in the length of the free path. The consequence of this is an increase in the number of
collisions and the formation of a larger number of ions.
The graph on the right is highlighted by a correlation in which an increase in the value of
the magnetic field induction makes the I–V characteristic linear. The essence of the explanation
of this phenomenon is that when an electron enters a linear trap, it begins to move in a cycloidlike manner. In other words, the length of the electron trajectory increases, and, consequently, the
ionization of a greater number of atoms will occur.
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Influence of the material and shape of the target
Target made of aluminum (curve 1) and copper
(curve 2) at a constant pressure of 0.5 Pa and a
magnetic field induction of 0.08 T
New (solid lines) and eroded (dashed lines) Al
target at a magnetic field induction of 0.06 T
Explanation:
An essential feature in the above graphs is the influence of the material and shape of the
target on the CVC. Improving the conditions for plasma localization can be achieved by forming
a recess in the eroded target.
Influence of pressure and magnetic field on the discharge voltage
(at direct current)
Solid curve at a discharge current of 1 A,
dashed curves at 3 A
Cylindrical MRU (at constant discharge
current and pressure)
Explanation:
In the graphs above, an essential feature is the deviation of the CVC from a linear
character. The reason for this phenomenon is the low pressure and induction of the magnetic
field, which indicates the escape of high-energy electrons from the plasma region, since their
cyclotron radius exceeds the distance between the cathode and anode. The graph on the right is
also explained, but unlike the graph on the left, a further increase in the value of the magnetic
field induction causes electron recapture.
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