Microsystems Technology Laboratories

In case of emergency, such as arcing in the chamber, do the following:

1. Turn off the Variac toggle switch, turn down the dial.
2. Close the HI-VAC valve tightly.
3. Find MTL Staff.

Preparation

1. Clean your samples (RCA/piranha-HF/other)
2. Check system to verify it is in proper standby condition:
   
   1. Hi-VAC valve - closed
   2. ROUGHING valve - closed
   3. REGEN valve ­ closed
   4. N2 vent - closed
   5. ROUGHING pump ­ on
   6. Cryo/compressor ­ on

Loading

(always wear vinyl gloves inside the lab, put fresh pair on when working w/ open chamber.)

1. Open the N₂ vent to bring the bell jar to atmosphere. Watch the roughing pump (TC₂) gauge; if it moves above 50 mtorr, close the N₂ vent and seek assistance, as the roughing valve may be leaking.
2. Raise the bell jar when it is at atmosphere, and close the N₂ vent.
3. Lift shielding, clip "up". Choose correct shielding; the old, light-gauge metal one is for Ti, Cr, Al, and standard processing ONLY; new, heavy gauge one is for all non-standard processing.
4. Check crystal life by turning on Sycon deposition monitor, switch in the back right, then press "life" to see what percentage of the crystal1s operating life is left. It should be 85% or better, otherwise, replace crystal, (Sycon 315/463-5297, PN 500-117) by removing the crystal cup holder, disposing of old crystal, and inverting new crystal over crystal holder, allowing it to drop into the cup w/o touching it. Replace the crystal cup.
5. Using hex key and adjustable wrench, load your evaporation boat in the chamber. We have been using Kurt J. Lesker (800.245.1656) part # EVS 3010W but many types will work. Consider that your settings will only be consistent if you use the exactly same type of boat on each run.
6. Put your material to be evaporated into the boat.
7. Position the shutter between the filament and your sample. Note it is turned counter-clockwise to be moved away.
8. Lower shielding material, make sure clean glass slides are in window openings.
9. Clean base plate and bell jar gasket where they will seat, using methanol only. Lower bell jar; make sure seats well.

Pump-down

Note: NEVER open the REGEN valve in normal operation!

1. Open ROUGHING valve, while holding down bell jar.
2. Close ROUGHING valve when bell-jar pressure (TC₁) and TC₂ drop below 50mTorr. This should take about 10 minutes. To help your Hi-VAC minimum pressure and rate, back-fill the bell jar with N₂ on one or two occasions during rough pumping. Do this by closing the ROUGHING valve, and opening N₂ vent for about 2 seconds, until bell jar pressure goes up to about 500mT, then closing N₂ and opening ROUGHING again. This will help remove light gasses like H, He from the chamber.
3. After reaching 50mT, slowly open the HI-VAC valve.
4. Turn on the ion gauge controller, for monitoring chamber pressure. Never turn on ion gauge unless in HI-VAC
5. Input data into the Sycon. Choose a program number, hit enter, and when prompted for material parameters, input as appropriate. After programming, go back to the normal operating screen, and make sure the shutter setting is now closed.

Evaporation

1. When pressure reaches into the 10-7 torr range, but not before 45 minutes, turn (side mounted) Variac to zero and flip (top box) FILAMENT toggle switch ON.
2. Turn on the crystal cooling water, in two places in back of the machine.
3. Turn Variac up slowly, but steadily. NOTE: You will need to do an "open shutter" characterization run with your boat and evaporation material to determine where on the Variac dial your material just starts to evaporate at a very low rate. In a normal run, you will normally heat your sample up to this point with the shutter "closed", then open the shutter at this point only, having allowed impurities to burn off, and let material to melt, w/o contaminating your samples.
4. Now, push the crystal monitor shutter button "open", and manually open the evaporator1s shutter.
5. Turn Variac up higher, until the deposition rate is at your target rate, usually 1-5 A/s. DO NOT turn Variac above 180. When the monitor shows the correct film thickness, close the shutter of the evaporator and push the monitor shutter button "closed". NOTE: If your evaporation rate starts to fall not due to your lowering the power setting, perhaps the crystal is failing or your evaporation source has been used up.
6. Turn Variac to zero.
7. Turn the FILAMENT toggle OFF
8. Close HI-VAC tightly. Wait five minutes, at least, before venting system. The system should not be opened if it is too hot, as your sample will likely oxidize.
9. Fill out a run sheet.

Evaporation

1. When pressure reaches into the 10-7 torr range, but not before 45 minutes, turn (side mounted) Variac to zero and flip (top box) FILAMENT toggle switch ON.
2. Turn on the crystal cooling water, in two places in back of the machine.
3. Turn Variac up slowly, but steadily. NOTE: You will need to do an "open shutter" characterization run with your boat and evaporation material to determine where on the Variac dial your material just starts to evaporate at a very low rate. In a normal run, you will normally heat your sample up to this point with the shutter "closed", then open the shutter at this point only, having allowed impurities to burn off, and let material to melt, w/o contaminating your samples.
4. Now, push the crystal monitor shutter button "open", and manually open the evaporator's shutter.
5. Turn Variac up higher, until the deposition rate is at your target rate, usually 1-5 A/s. DO NOT turn Variac above 180. When the monitor shows the correct film thickness, close the shutter of the evaporator and push the monitor shutter button "closed".
   NOTE: If your evaporation rate starts to fall not due to your lowering the power setting, perhaps the crystal is failing or your evaporation source has been used up.
6. Turn Variac to zero
7. Turn the FILAMENT toggle OFF
8. Close HI-VAC tightly. Wait five minutes, at least, before venting system. The system should not be opened if it is too hot, as your sample will likely oxidize.
9. Fill out a run sheet.

Unloading

(HI-VAC, ROUGHING, AND REGEN valves are shut)

1. Open N₂ vent valve. If gauge TC₂ goes above 50 mtorr, close N₂ vent and seek assistance.
2. When bell jar reaches atmosphere, raise the bell jar and shielding and close N2 vent.
3. Remove samples and control (slide)
4. Replace glass window slide in shield, lower shield.
5. Clean bell-jar gasket and the mating surface of the base plate, lower bell jar

Shut-down

1. Open ROUGHING valve, making sure bell-jar seals with base plate.
2. Close ROUGHING valve when pressure drops below 25mtorr
3. Verify standby conditions:
   
   1. a.HI-VAC valve ­ closed
   2. ROUGHING valve ­ closed
   3. REGEN valve ­ closed
   4. N₂ vent - closed
   5. ROUGHING pump ­ on
   6. Cryo/compressor ­ on
   7. Cooling water ­ on

    

Regen (lab staff only!)

(HI-VAC, ROUGHING, and N2 valves are closed)

1. Turn off compressor/cryo unit. This will allow the cryo to heat-up overnight, or if using N₂ bleed, several hours. Poppet valve will pop when at atmosphere. Close N₂.
2. Open REGEN valve, until TC₂ down to 30u and 2 hrs min, then close REGEN. Cycle several minutes of alternating N₂ bleed and open REGEN, bringing down to 30u w/ each REGEN.
3. Turn on cryo/compressor pump. Make sure cryo pump is dominant over ROUGHING pump before closing REGEN valve (may be instantaneous).
4. The cryo temp gauge s/b about 10-15K w/in 2hrs.