The thermal evaporator uses resistive energy to evaporate thin films onto a given substrate. It can deposit materials with a specified thickness of up to 1500 nanometers. The thickness is controlled by the use of a quartz crystal monitor. Evaporants used in the BYU lab include silver, gold, aluminum, nickel, and chromium. Eighteen wafers can be processed simultaneously. Up to three different layers may be evaporated in one run.
Power Supply: 3500 W
Cryopump: Pressure of 10-8 Torr
Sources: 3 in parallel individually selectable.
Substrate Heat Control: 0 - 540 Degrees Celsius
Measurements: 43"x84"x35" (Width x Height x Depth)\
External Tube Diameter: 20"
Start up evaporator, program deposition meter
The nitrogen and vacuum should be on at all times.
Turn on power supply
Make sure the chiller is on.
On deposition meter, select preprogrammed option OR
Press program to enter programming mode
Display should change to that shown here
Press enter ([E]) until selector bar is over large number on left titled film
Extensive list of material parameters available in XTM/2 Deposition Monitor Operating Manual
Open bell jar and load wafers and targets
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Flip function selector switch from "OFF" to "Manual" Caution both vacs must be shut!
Flip nitrogen vent switch until bell jar vents (you will hear and feel nitrogen escaping). Close nitrogen.
need to take picture.
Flip function selector switch to "OFF"
This step prevents accidental opening of the vacuum valves.
Flip raise bell jar switch. There will be a 10s delay and the jar will then open. When jar is completely raised, flip switch back to middle position.
Insert wafers: Wafers snap into place. Replace glass slides with new clean ones. Close shutter.
shutter operation
select electrode ( front middle back). Load targets.
Types of targets: boats and rods
Establish orbiter's rotation speed.
Slider switch in middle position turns orbital on.
Use speed dial to adjust rotational speed.
Look inside to top of bell jar to gauge speed.
Turn off orbital before lowering bell jar.
Close bell jar and pump down the chamber
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Flip bell jar switch down. As before there is a 10 second delay before the jar begins to lower.
Pay attention as jar lowers. It sometimes hangs up on the orbital structure. If it makes contact with the orbitals, flip the switch back up immediately; raise the jar & retry.
Open rough pump
Flip switch to manual
Open roughing switch.
Turn on thermogauge power. Wait until pressure drops to .5 torr.
See Pictures for above instructions
Initiate cyropump.
Turn off roughing pump. Make sure switch is all the way closed (i.e. hissing sound had stopped) before flipping up the high vac switch.
The pressure needle should bury left.
flip ionization gauge gauge to 10-4 range
Turn on filament power. Turn on degas & wait 5 mins. If the selector switch is above 10-4, the filament will turn off and you won't get any pressure readings.
Turn off degas. When gauge gets to 2 range, flip selector to 10-5. repeat for 10-6. you may have to wait 30-60 mins for the pump to get down past 4x10-6
Begin Evaporation
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Turn on heater power. Make sure selector switch is on 100amps (bottom numbers)
Rotate current dial slowly increasing current.
If you approach 80 amps, flip the selector switch from 100 to 500.
The amount of current required varies for diferent metals. This link describes specific process recipies.
When you begin to get a deposition, press open shutter on deposition meter and open shutter inside bell jar by flipping shutter switch down.
Dep meter gives timer + thickness
Adjust current up or down to maintain ideal deposition rate for specific metal.
At desired thickness, close shutter.
Slowly ramp down current when finished.
Open bell jar
Turn off high vac switch (see step 5)
Wait 10 mins for everything to cool down.
Follow remaining steps in 3b.
Turn off Equipment
In the Back
Turn off vac
Turn off nitrogen (if no one else is using it.)
For pictures see step 1.
Open rough vac briefly to seal shamber
Make sure heater power is off, gauge power is off
Turn off main power breaker
Troubleshooting
For more information on thermal evaporation, see our Metal Deposition page.
Quick Materials Evaporation Reference
1) Quick reference for materials common to IML lab
Metal
Cr
Au
Ni
Cu
Al
Density
7.2
19.3
8.91
8.93
2.7
z-ratio
0.305
0.381
0.331
0.437
1.08
Current (A)
80
190
185
190
200
Dep. Prog#
2
3
-
-
1
2) Table of density and Z-ratio values
Material
Symbol
Melting Temperature (°C)
Density (bulk, g/cm3)
Z-Ratio
Aluminum
Al
660
2.7
1.08
Antimony
Sb
631
6.62
0.768
Arsenic
As
612
5.73
0.966
Barium
Ba
729
3.5
2.1
Beryllium
Be
1287
1.85
0.543
Bismuth
Bi
271
9.78
0.79
Boron
B
2067
2.535
0.389
Cadmium
Cd
321
8.65
0.682
Cadmium sulfide
CdS
1750
4.83
1.02
Cadmium telluride
CdTe
1041
6.2
0.98
Calcium
Ca
839
1.55
2.62
Calcium fluoride
CaF2
1360
3.18
0.775
Carbon (diamond)
C
3550
3.52
0.22
Carbon (graphite)
C
3652
2.25
3.26
Chromium
Cr
1857
7.2
0.305
Cobalt
Co
1495
8.71
0.343
Copper
Cu
1083
8.93
0.437
Copper(I) Sulfide (Alpha)
Cu2S
1100
5.6
0.69
Copper(I) Sulfide (Beta)
Cu2S
1100
5.8
0.67
Copper(II) Sulfide
CuS
1100
4.6
0.82
Gallium
Ga
30
5.93
0.593
Gallium arsenide
GaAs
1238
5.31
1.59
Germanium
Ge
937
5.4
0.516
Gold
Au
1063
19.3
0.381
Gold Germanide
AuGe(12%)
-
17.63
0.3972
Indium
In
157
7.24
0.841
Indium antimonide
InSb
535
5.76
0.769
Indium tinide
InSn(80-20wt%)
-
7.25
0.8176
Iridium
Ir
2434
22.4
0.129
Iron
Fe
1536
7.86
0.349
Lead
Pb
327
11.342
1.13
Lead sulfide
PbS
1114
7.5
0.566
Lithium
Li
181
0.534
5.9
Lithium fluoride
LiF
896
2.64
0.774
Magnesium
Mg
649
1.74
1.61
Magnesium oxide
MgO
2642
3.58
0.411
Manganese
Mn
1244
7.44
0.377
Manganese Sulfide
MnS
-
3.99
0.94
Material
Symbol
Melting Temperature (°C)
Density (bulk, g/cm3)
Z-Ratio
Mercury
Hg
-39
13.6
0.74
Molybdenum
Mo
2617
10.2
0.257
Nickel
Ni
1453
8.85
0.331
Nickel chromide
NiCr(80-20wt%)
-
8.52
0.3258
Niobium
Nb
2467
8.57
0.493
Palladium
Pd
1552
12.16
0.357
Platinum
Pt
1770
21.37
0.245
Potassium chloride
KCl
770
1.98
2.05
Selenium
Se
221
4.82
0.864
Silicon
Si
1412
2.34
0.712
Silicon dioxide (fused quartz)
SiO2
1610
2.2
1.07
Silicon monoxide
SiO
1702
2.13
0.87
Silver
Ag
961
10.492
0.529
Silver bromide
AgBr
432
6.47
1.18
Silver chloride
AgCl
455
5.56
1.32
Sodium
Na
98
0.971
4.8
Sodium chloride
NaCl
800
2.17
1.57
Sulfur
S8
115
2.07
2.29
Tantalum
Ta
2977
16.6
0.262
Tellurium
Te
450
6.25
0.9
Tin
Sn
232
7.3
0.724
Titanium
Ti
1670
4.5
0.628
Titanium oxide
TiO
-
4.9
N/A
Titanium dioxide
TiO2
1825
4.26
0.4
Tungsten
W
3380
19.3
0.163
Tungsten carbide
W2C
2860
15.6
0.151
Uranium
U
1132
18.7
0.238
Vanadium
V
1902
5.87
0.53
Ytterbium
Yb
824
6.96
1.13
Yttrium
Y
1526
4.48
0.835
Zinc
Zn
420
7.14
0.514
Zinc oxide
ZnO
1975
5.61
0.556
Zinc selenide
ZnSe
1100
5.42
0.722
Zinc sulfide
ZnS
1700
4.1
0.775
Zirconium
Zr
1852
6.53
0.6
Material
Symbol
Melting Temperature (°C)
Density (bulk, g/cm3)
Z-Ratio
Aluminum (Al)
New boat:
Slowly ramp current (50 Amps/min) up to 200 Amps.
Wait (patiently) until samples are molten.
Slowly increase current until the deposition rate is nonzero.
More rapidly increase deposition rate to 10 Å/s.
Maintain this deposition rate until you have reached desired thickness or sample is depleted.
Slowly ramp current down (50 Amps/min) to zero.
Used boat:
Slowly ramp current (50 Amps/min) up to 250 Amps.
Wait 15 min.
Increase current to 300.
Wait (patiently) until samples are molten. Depending on the condition of the boat, you may need to increase the current above 300 to get the aluminum to melt.
Slowly increase current until the deposition rate is nonzero.
More rapidly increase deposition rate to 10 Å/s.
Maintain this deposition rate until you have reached desired thickness or sample is depleted.
Slowly ramp current down (50 Amps/min) to zero.
Notes:
If you ramp too quickly, you'll break the boats. If you vent the chamber too quickly, you'll break the boats.
If you are doing multiple depositions, you do not need to let the chamber cool down between depositions.
Aluminum alloys with the tungsten boats, so you won't be able to evaporate your entire sample. Don't be afraid to ramp up the current (slowly) and try to evaporate as much as possible, but don't go above 400 Amps. You'll blow a fuse.
Pressure should be in 10-6 range.
Maximum deposited from one boat: 6200 Å.
Ideal deposition rate: 10 Å/s.
Number of aluminum pellets on boat not to exceed three.
Ideal "warm up current": 200 Amps.
Program number on deposition meter: 1.
Chromium (Cr)
Ramp current up slowly (50 Amps/s) to 80 Amps.
Let rod warm to a healthy glow.
Increase current slowly until the deposition rate is nonzero.
Increase current to obtain desired deposition rate.
Notes
Data based on use of chromium on tungsten rod.
Rods tend to break if current ramped too quickly, particularly when ramping down.
Chrome sublimes.
High deposition rates are possible, but current tends to max out around 120 Amps. Further increases in current do little good and may cause additional strain on rod??