Andrew J. Gellman Group S.O.P.
Surface Cleaning (Sputtering/Annealing Cycles) using the Omicron ISE-10 Ion Gun
- LOOK inside the chamber to verify:
Check chamber vacuum pressure (should be in UHV range before turning on equipment).
Fill thermocouple reference dewar with an ice bath.
Remove condensed water from bottom of manipulator tube using vacuum line connected to aspirator.
Run titanium sublimation pump.
Turn on ion gun and mass spectrometer electronics.
Check manifold vacuum pressure and evacuate line using the turbopump before filling with argon.
- Tribometer is out of the way and safe.
- Manipulator crystal is in sputtering position.
- Shield is in place over electron gun and analyzer cones.
Connect themocouple and heating wires to manipulator crystal.
Fill liquid nitrogen funnel to begin cooling manipulator crystal.
Leak argon into the chamber by opening the leak valve while monitoring chamber pressure until a chamber pressure no greater than 1(10)-8 Torr. (It may take as many as 5 full turns to begin Ar flow.)
The purpose of this is to ensure argon purity using the mass spectrometer before beginning sputtering. If air (oxygen) is detected, close the leak valve and find out how Ar is getting contaminated before proceeding with sputtering.
Turn off mass spectrometer.
Close ion pump valve (Chamber pressure will begin to rise again).
Allow pressure to rise until about 5(10)-6 Torr is read on the ion gauge.
Ensure turbo pump is closed to all areas except to the 6-way cross leading to the chamber. (Pump both manipulator rotary stages using the roughing pump only at this point).
Open turbo pump to the chamber (Chamber pressure will begin to decrease).
Slowly continue to open the leak valve until a chamber pressure of about 1(10)-5 Torr is reached.
Operate the ion gun electronics in the following manner:
- Close the needle valve closest to the argon lecture bottle.
- Open argon lecture bottle valve and close.
- Close valve to turbopump (and all pumps).
- Slowly open needle valve while watching the analog valve connected to the manifold until a gage pressure of 10 psi, then close needle valve.
- Allow manifold pressure to equilibrate for one minute.
- Close valve leading to the ion sputter gun (this line is now charged with Ar and ready for sputtering).
- Open all valves leading to the roughing pump to pump the manifold into vacuum.
Slowly open the leak valve to allow more Ar flow while monitoring the extraction current until a current of 25mA is reached (as read on the ISE-10 gun control power supply).
Optimize the position of the crystal to read a crystal current of about 8 µA and visually ensure the crystal is in the line of sight of the ion gun.
Once crystal is sufficiently cold (~120K), anneal while sputtering for several cycles…
- Operate and HV to ON.
- Increase electron emission to 0.10mA.
- Increase beam energy (slowly) to 1000 V.
- Slowly increase electron emission and beam energy in a step wise manner until 10.0mA and 5kV are reached.
- Allow one minute to stabilize.