Teer Coatings Ltd.
A New High Rate Magnetron
---Characteristics & Applications
D.G. Teer
Teer Coatings Ltd., UK
www.teercoatings.co.uk
1
Background
N
S
N
Closed
magnetic
field
system
Target
S
S
N
N
S
S
Magnetron
Sample
holder
N
S
N
• TCL coatings are deposited using patented Close Field Unbalanced
Magnetron Sputter Ion Plating (CFUBMSIP) system
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Background
System for coating up
to 432 drills (∅ 10 mm)
per run
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New high power density magnetron
Target size 380 X 175 mm
Magnetic field above the target
stronger than for a conventional
magnetron
Optimised water cooling system
Typical rectangular magnetrons
manufactured by TCL
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Experimental configuration
Closed magnetic
field
OES
viewport
N
S
S
N
N
S
Counterpart
magnetron
Flat ring jig/
sample holder
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High
power
magnetron
Vacuum
chamber
Ti, Al or Cu
target
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Experimental condition
• Ar flow: 4 – 70 sccm ⇒ pressure variation 0.075 – 5.2 Pa
• “Advanced Energy” MDX-II DC power generators with
max output 15 kW
• I-V reading from generator panel set in current regulation mode
• OES measurements by EP200 Verity Instrument monochromator
in manual mode, FWHM > 1 nm.
• During deposition sample holder revolved at 4 rpm
• Deposition substrate to target distance 150 mm
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I-V characteristics (Al, Cu and Ti)
550
Gas - Ar
p = 0.24 Pa
500
V (V)
450
400
350
CM-Cu
HPM-Cu
300
CM-Al
HPM-Al
250
CM-Ti
HMP-Ti
200
0
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15
30
45
I (A)
60
75
90
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I-V characteristics (Ti target)
500
Target material - Ti
Gas - Ar+N2
450
p (Pa)
0.30
V (V)
400
0.17
350
300
250
200
0
10
20
30
40
50
I (A)
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I-V characteristics (Al target)
550
Target material - Al
Gas - Ar
500
p (Pa)
V (V)
450
0.09
0.17
400
0.30
350
0.7
0.30
300
250
200
0
10
20
30
40
50
I (A)
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Ion current to the -50V biased substrate
4.5
4
p=0.30 Pa
3.5
Ijig (A)
3
2.5
HPM-Ti
2
HPM-Al
1.5
CM-Al
1
0.5
0
0
2
4
6
8
10
12
14
16
Pmag (kW)
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Deposition of TiN coating
Deposition conditions
• 2 opposing unbalanced HPMs
•12.5 kW at each target
• Sample rotation at 4 rpm
• OEM controlled introduction of N2
• 50 min deposition time
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Coating characteristics:
• Total thickness 3.36 μm
• Deposition rate 4 μm/h ⇒ 4
times higher than from CMs
• Hardness – 33 GPa
• Good scratch result
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Deposition of Cu coating
Deposition conditions:
• Single unbalanced HPM
without closed field
Coating characteristics:
• Total thickness 8.0 μm
• Deposition rate ≈ 30 μm/h
• 28 kW at the Cu target
• Sample rotation at 4 rpm
• Deposition time 16 min
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Graphit-iCTM coatings
Graphit-iCTM (a-C)
Sputtered a-C doped with Cr
Dense amorphous structure
Very low friction (<0.1 in dry sliding)
Very low specific wear rate (<6x10-17 m3.N-1.m-1)
High load bearing capacity (>2.5GPa)
Electrically conducting
Current commercial applications
Automotive components, machinery & Tools,
decorative & electrical applications
Development of Graphit-iC coatings
Increase deposition rate (e.g. fuel cell application)
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Deposition Equipment
Two magnetrons of the new design
used in place of conventional
magnetrons
Cr
C
C
Cr
(Target size 380 x 175 mm)
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Graphit-iCTM coating procedure
A three step process is ued for the deposition of Graphit-iCTM
• ion cleaning
• deposition of a thin metallic chromium layer
• deposition of the C / Cr layer
1.8 μm
0.2 μm
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Magnetron Characteristics
Current-voltage curve for conventional
and high power magnetrons
700
650
Voltage / V
600
550
500
450
HPM1
400
HPM2
Conventional design
350
300
0
1
2
3
4
5
6
7
8
9
10
Current / A
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Magnetron Characteristics
Current-Power graph for target 380mm x 175mm
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Power / kW
7
6
5
4
HPM1
3
HPM2
2
Conventional
1
0
0
2
4
6
8
10
12
14
Current/ A
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Ion currents at substrate holder
Magnetron
Design
C Target
*/ A
Cr Target
**/A
Bias
/V
Ion current
recorded /A
Conventional
3.5
0.25
60
0.46
HPM
9.0
0.40
60
1.25
HPM
12.0
0.54
60
1.65
* applied to each of two carbon targets
* *applied to one of two chromium targets
¾ Ion current is significantly increased by the higher powers
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Deposition Rates
C
target power
/ kW
Graphit-iC
Layer
thickness
/ µm
Graphit-iC
Graphit-iC/
/ hrs
µm/hr
Conventional
2.2 - 2.4
1.8 - 2.0
4
0.45 - 0.5
HPM
5.0 - 5.2
1.8 - 1.9
2
0.9 – 0.95
HPM
6.7 - 7.1
2.4/2.5
2
1.2 /1.35
Magnetron
Design
Deposition time Deposition rate
Summary
• Power input increased by up to 3 times.
• Deposition rates increased by 2 to 2.7 times depending on the chosen
target power
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Coating Properties
3.5A (2.2 kW)
9A (5.1 kW)
12A (6.9 kW)
Surface Quality – Optical microscope
Adhesion – Indentations from 150kgf Rockwell Test VDI 3198/1991
Hardness – Fischerscope H100 (testing load 50mN)
1769 kgmm-2
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1519 – 1729 kgmm-2
1554 kgmm-2
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Tribological properties - Wear
3.5A (2.2 kW)
9A (5.1 kW)
12A (6.9 kW)
Specific Wear rates in m3/Nm ( 80N POD test in air against WC/Co )
2.1 x10 -17
Pin-on-disc wear tracks
2.8 x10 -17
2.9 x10 -17
Taper sections through wear tracks
(produced by ball crater technique)
Summary : Specific wear rate comparable at low and high deposition rates.
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HPM at Different Powers
Graphit-iC coatings produced at different target currents
Magnetron
Design
C Target
*/ A
Cr Target
**/A
Specific Wear Rate
80N POD
/ m3N-1m-1
Stable
Friction
Coefficient
Conventional
3.5
0.25
2.1 x10-17
0.07
HPM
2.5
0.18
2.7 x10-17
0.07
HPM
5.0
0.25
3.3 x10-17
0.08
HPM
9.0
0.40
2.8 x10-17
0.08
HPM
12.0
0.54
2.9 x 10-17
0.09
* applied to each of two carbon targets
** applied to one of two chromium targets
¾ The new magnetron can be operated at low powers if required for temperature
sensitive materials – e.g. bearing steels.
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TEM results on Graphit-iC coating
Cr interface layer
Cr/C superlattice layers ~3 nm
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TEM results on Graphit-iC coating
102
(006)
a-C phase with (006) basal
plane crystalline cluster
perpendicular to the surface
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Conclusions (1)
¾ High power density magnetron with 665 cm2 industrial size
sputter target has been designed and successfully tested
¾ Stable operation of HPM with Cu & Ti targets up to 30 kW
(80 W/cm2) and with Al target up to 15 kW (40 W/cm2) was
demonstrated
¾ Current-voltage characteristics exhibit large increase in
current with little or no increase in voltage, indicating high
efficiency of plasma confinement above the target
¾ Deposition experiments demonstrate substantial increase
of deposition rate, proving possibility of cost effective
processes based on HPMs.
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Conclusions (2)
¾ Target power was increased by up to 3 times
¾ Low voltage operation deposition rates were increased by up
to 2.7 times
¾ No detrimental effects were observed on the coating hardness
or coating tribological properties at fast deposition rates
¾ No significant increase in surface defects was observed
¾ The high power magnetron design can also be used
successfully at lower powers for temperature sensitive
substrates
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Acknowledgements
Thanks to:
Dr. A. Grouppa who did most of the development
work on the High Rate Magnetron and to Sue Field
for her work on the Graphit-iC coatings
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Teer Coatings Ltd.
www.teercoatings.co.uk
West Stone House,
Berry Hill Ind. Estate,
Droitwich,
Worcestershire,
WR9 9AS.
U.K.
www.teercoatings.co.uk
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