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Evaporation of Carbon

• Prepare carbon rods.
  • One carbon rod should have a sharpened point or a reduced section.
  • The second carbon rod may have a pointed end, a flattened end or a shelf cut in the end.
• Turn off discharge gauge.
• Turn on nitrogen.
• Turn switch on auto console to vent.
• Turn off nitrogen when bell jar is vented.
• Lift bell jar.
• Place pointed carbon rod in electrodes on right side with spring.
• Place second carbon rod in other right electrode. If a shelf is cut, the extended portion of the end should be oriented away from the stage.
• Push carbon rods together so that the ends make contact and about 0.5 cm of tension is established with spring on one electrode.
• Place specimens on stage.
• Place a white porcelain dish with a drop of oil on stage to monitor thickness of deposited carbon layer.
• Adjust horizontal position and angle of stage if necessary.
• Adjust height of electrodes if necessary.
• Wipe bell jar gasket and base plate to remove particulate matter.
• Replace bell jar. Switch to auto on auto console.
• Turn thermocouple gauge to TC1.
• When thermocouple vacuum gauge reads below 50, move auto console switch to auto.
• When back and high vac lamps on auto console remain illuminated, turn thermocouple gauge to TC2.
• When vacuum gauge on auto console reads below 5 mm:
  • Turn on discharge gauge.
  • Turn range selector switch to 0 and wait 30 sec.
  • Adjust to 0 with zero adjust knob.
  • Press vacuum read switch. If high voltage disconnects, wait a few sec. and press again.
  • Turn range selector switch until reading is above 1.
  • Return switch to 0 and readjust to 0 with zero adjust knob.
  • Turn range selector switch until reading is above 1. Turn each time reading falls below 1.
• Fill cold trap with liquid N2 .
• Wait until discharge gauge reads 10(-6) or better.
• Turn filament selector switch to right electrodes.
• Turn transformer selector to filament.
• Turn on power to monitor (separate box).
• Turn on filament power switch.
• Turn filament adjust knob slowly until carbon rods glow (20-30 amp) and de-gas rods for 5-10 sec.
• Turn filament adjust knob to 0.
• For even evaporation, turn switch for rotary stage to on and adjust speed to 0.5-2 rev/sec.
• Turn filament adjust knob slowly until gauge reads desired setting for evaporation.
  • For rapid deposition:
    • Slowly increase current until narrow tip of carbon rod begins to glow.
    • Rapidly increase current to 40-50 amp. Pause for 0.5-1 sec.
    • Rapidly decrease current to 0.
  • For slow deposition:
    • Turn filament current to intermediate position between glow position and full current (34-36 amp).
    • Pause for several sec to 1 min depending on desired thickness.
    • Turn filament current control to 0.
• Check thickness of carbon layer by observing the color of the dish compared to the color under the oil drop.
  • A layer of 5 nm of carbon will produce a barely perceptible change in color.
  • The color may be checked during deposition of carbon by turning off current to electrodes.
• Turn filament power switch to off. Let chamber cool for a few minutes before opening.
• Turn off discharge gauge.
• Vent bell jar and remove specimens.
• Replace bell jar.
• Switch to auto and evacuate.

Evaporation of Metal

• Wrap platinum or platinum/palladium wire (2-5 cm) closely around point of tungsten filament bent into V shape making about 10-15 turns.
• Rinse filament in 95% ethanol to remove grease
• Turn off discharge gauge.
• Turn on nitrogen.
• Turn switch on auto console to vent.
• Turn off nitrogen when bell jar is vented.
• Lift bell jar.
• Place tungsten filament between electrodes on left side with point of filament oriented toward stage.
• Adjust height of electrodes to give desired angle for evaporation.
• Place carbon rods between electrodes on left side.
• Adjust height of electrodes if necessary.
• Place specimens on stage.
• Place a white porcelain dish with a drop of oil on stage to monitor thickness of deposited carbon layer.
• Adjust horizontal position and angle of stage if necessary.
• Wipe bell jar gasket and base plate to remove particulate matter.
• Replace bell jar. Switch to auto on auto console.
• Turn thermocouple gauge to TC1.
• When thermocouple vacuum gauge reads below 50, move auto console switch to auto.
• When back and high vac lamps on auto console remain illuminated, turn thermocouple gauge to TC2.
• When vacuum gauge on auto console reads below 5 mm:
  • Turn on discharge gauge.
  • Turn range selector switch to 0 and wait 30 sec.
  • Adjust to 0 with zero adjust knob.
  • Press vacuum read switch. If high voltage disconnects, wait a few sec and press again.
  • Turn range selector switch until reading is above 1.
  • Return switch to 0 and readjust to 0 with zero adjust knob.
  • Turn range selector switch until reading is above 1. Turn each time reading falls below 1.
• Fill cold trap with liquid N2 .
• Wait until discharge gauge reads 10(-6) or better.
• Turn filament selector switch to left electrodes.
• Turn transformer selector to filament.
• Turn on power to monitor (separate box).
• Turn on filament power switch.
• Turn filament adjust knob until metal is heated near but below melting point to burn off contaminants and de-gas filament. Turn filament adjust knob to 0.
• Wait until discharge gauge reads 10(-6) or better.
• WITH EYES PROTECTED WITH DARK GLASS OR PLASTIC, turn filament adjust knob slowly until metal wire just melts and coalesces.
• Increase current about 3-4 amp very slowly over the next 10-60 sec to keep metal molten. Evaporation time should be kept short, but metal should not sputter.
• Turn filament adjust knob to 0.
• Turn off filament power switch.
• Turn filament selector switch to right electrodes.
• Turn on filament power switch.
• Turn switch for rotary stage to on and adjust speed to 0.5-2 rev/sec.
• Turn filament adjust knob slowly until gauge reads desired setting for evaporation.
  • For rapid deposition:
    • Slowly increase current until narrow tip of carbon rod begins to glow.
    • Rapidly increase current to 40-50 amp. Pause for 0.5-1 sec. Rapidly decrease current to 0.
  • For slow deposition:
    • Turn filament current to intermediate position between glow position and full current (34-36 amp).
    • Pause for several sec to 1 min depending on desired thickness.
    • Turn filament current control to 0.
• Check thickness of carbon layer by observing the color of the dish compared to the color under the oil drop.
  • A layer of 5 nm of carbon will produce a barely perceptible change in color.
  • The color may be checked during deposition of carbon by turning off current to electrodes.
• Turn filament power switch to off. Let chamber cool for a few minutes before opening.
• Turn off discharge gauge.
• Vent bell jar and remove specimens.
• Replace bell jar.
• Switch to auto and evacuate.

To pump down manually if necessary

• With switch on auto console in manual, close all valves with switches.
• Turn on mechanical pump.
• Turn on thermocouple gauge.
• Turn thermocouple gauge to TC1.
• Vacuum reading should drop quickly below 50 mm.
• Open backing valve. Evacuate system below main valve and diffusion pump to about 50 mm.
• Close backing valve and open roughing valve. Evacuate bell jar to about 50 mm.
• Close roughing valve. Open backing valve.
• Turn on diffusion pump.
• Turn on water.
• Allow diffusion pump to warm up about 10 min.
• Close backing valve.
• Open roughing valve.
• Re-pump bell jar to about 50 mm.
• Close roughing valve.
• Open backing valve.
• Turn thermocouple gauge to TC2.
• Open high vac valve (main valve).
• When thermocouple gauge reaches 5 mm or below, turn on discharge gauge.
• Proceed according to instructions for automatic pump down.