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Thermal Evaporator

slideNumber:

CHA-600

Contact Information

CHA Industries Faculty Contact: Aaron Hawkins
Maintenance Request Staff Contact: Jim Fraser
SCHEDULER IS REQUIRED Student Contacts: Matt Hamblin
General Information
Equipment Specifications
Operating Procedure
Evaporation Reference
Processes & Deposition Data

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.

  1. Power Supply: 3500 W
  2. Cryopump: Pressure of 10-8 Torr
  3. Sources: 3 in parallel individually selectable.
  4. Substrate Heat Control: 0 - 540 Degrees Celsius
  5. Measurements: 43"x84"x35" (Width x Height x Depth)\
  6. External Tube Diameter: 20"

Start up evaporator, program deposition meter

  1. The nitrogen and vacuum should be on at all times.
  2. Turn on power supply
  3. Make sure the chiller is on.
  4. On deposition meter, select preprogrammed option OR
    1. Press program to enter programming mode
    2. Display should change to that shown here
    3. Press enter ([E]) until selector bar is over large number on left titled film
    4. Enter desired program number according to chart
    5. Press program to exit programming mode

Program deposition meter

    1. Press program
    2. Display should change to that shown here
    3. Set stop thickness. Press enter until density slot is selected.
    4. Set density. Press Enter.
    5. Set Z-value Press Enter.
    6. Tooling factor should be ---%. If so, Press program, you're done.
  1. See Video of deposition meter being programmed
    1. Partial List of common material properties
    2. Extensive list of material parameters available in XTM/2 Deposition Monitor Operating Manual

Open bell jar and load wafers and targets

  1. Flip function selector switch from "OFF" to "Manual" Caution both vacs must be shut!
  2. Flip nitrogen vent switch until bell jar vents (you will hear and feel nitrogen escaping). Close nitrogen.
    1. need to take picture.
  3. Flip function selector switch to "OFF"
    1. This step prevents accidental opening of the vacuum valves.
  4. 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.
  5. Insert wafers: Wafers snap into place. Replace glass slides with new clean ones. Close shutter.
    1. shutter operation
  6. select electrode ( front middle back). Load targets.
    1. Types of targets: boats and rods
  7. Establish orbiter's rotation speed.
    1. Slider switch in middle position turns orbital on.
    2. Use speed dial to adjust rotational speed.
    3. Look inside to top of bell jar to gauge speed.
    4. Turn off orbital before lowering bell jar.

Close bell jar and pump down the chamber

  1. Flip bell jar switch down. As before there is a 10 second delay before the jar begins to lower.
  2. 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.
  3. Open rough pump
  4. Flip switch to manual
  5. Open roughing switch.
  6. Turn on thermogauge power. Wait until pressure drops to .5 torr.
  7. See Pictures for above instructions
  8. Initiate cyropump.
    1. 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.
      1. The pressure needle should bury left.
    2. flip ionization gauge gauge to 10-4 range
    3. 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.
    4. 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

  1. Turn on heater power. Make sure selector switch is on 100amps (bottom numbers)
  2. Rotate current dial slowly increasing current.
  3. If you approach 80 amps, flip the selector switch from 100 to 500.
  4. The amount of current required varies for diferent metals. This link describes specific process recipies.
  5. When you begin to get a deposition, press open shutter on deposition meter and open shutter inside bell jar by flipping shutter switch down.
    1. Dep meter gives timer + thickness
  6. Adjust current up or down to maintain ideal deposition rate for specific metal.
  7. At desired thickness, close shutter.
  8. Slowly ramp down current when finished.

Open bell jar

  1. Turn off high vac switch (see step 5)
  2. Wait 10 mins for everything to cool down.
  3. Follow remaining steps in 3b.

Turn off Equipment

  1. In the Back
    1. Turn off vac
    2. Turn off nitrogen (if no one else is using it.)
    3. For pictures see step 1.
  2. Open rough vac briefly to seal shamber
  3. Make sure heater power is off, gauge power is off
  4. 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)

  1. New boat:
    1. Slowly ramp current (50 Amps/min) up to 200 Amps.
    2. Wait (patiently) until samples are molten.
    3. Slowly increase current until the deposition rate is nonzero.
    4. More rapidly increase deposition rate to 10 Å/s.
    5. Maintain this deposition rate until you have reached desired thickness or sample is depleted.
    6. Slowly ramp current down (50 Amps/min) to zero.
  2. Used boat:
    1. Slowly ramp current (50 Amps/min) up to 250 Amps.
    2. Wait 15 min.
    3. Increase current to 300.
    4. 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.
    5. Slowly increase current until the deposition rate is nonzero.
    6. More rapidly increase deposition rate to 10 Å/s.
    7. Maintain this deposition rate until you have reached desired thickness or sample is depleted.
    8. Slowly ramp current down (50 Amps/min) to zero.
  3. Notes:
    1. If you ramp too quickly, you'll break the boats. If you vent the chamber too quickly, you'll break the boats.
    2. If you are doing multiple depositions, you do not need to let the chamber cool down between depositions.
    3. 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.
  4. Pressure should be in 10-6 range.
  5. Maximum deposited from one boat: 6200 Å.
  6. Ideal deposition rate: 10 Å/s.
  7. Number of aluminum pellets on boat not to exceed three.
  8. Ideal "warm up current": 200 Amps.
  9. Program number on deposition meter: 1.

Chromium (Cr)

    1. Ramp current up slowly (50 Amps/s) to 80 Amps.
    2. Let rod warm to a healthy glow.
    3. Increase current slowly until the deposition rate is nonzero.
    4. Increase current to obtain desired deposition rate.
    5. Notes
      1. Data based on use of chromium on tungsten rod.
      2. Rods tend to break if current ramped too quickly, particularly when ramping down.
      3. Chrome sublimes.
    6. 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??
    7. Ideal "warm up current": 80 Amps.
    8. Maximum thickness with one rod: ----
    9. Ideal deposition rate: ~30 Å/s.
    10. Pressure should be in 10-6 range.
    11. Program number on deposition meter: 2.

Nickel (Ni)

Gold (Au)

Other materials