Cambridge ALD

Cambridge ALD

Essentials
Full name	Savannah S100 (gen. 1)
Manufacturer	Cambridge NanoTech (Veeco)
Description	Atomic layer deposition system
Location	Cleanrooms 1 & 2
Responsibility
Primary	Martin
Secondary	Karolis

Current growth per cycle (GPC)

• File:ALD1.jpg
• File:ALD2.jpg

Available processes

Deposited material	Precursor	ALD1	ALD2	Ref.
Hafnium oxide (HfOx, HfO2)	TDMAH tetrakis(dimethylamino)hafnium [(CH3)2N]4Hf	Yes	Yes	[1]
Aluminum oxide (AlOx, Al2O3)	TMA trimethylaluminum (CH3)3Al	Yes	No	[2]

Standard operating procedure

• Open valve on top of the nitrogen bottle.
• Check nitrogen bottle pressure. Main bottle pressure should be at least 5 bar, line pressure 1-2 bar.

  If line pressure is outside of 1-2 bar range, carefully adjust the regulator valve.

• Make sure the valves of all precursors inside the ALD machine are closed.
• ALD1 only: run recipe Default_cleaning to pump out any residual gas in the gas lines.

  With flow set to 0 the actual flow can be between 0-1 sccm.

• Press the big round VENT button.
• Open the metal lid.
• Put your sample inside, roughly in the center, away from the gas inlet and outlet.

  Check whether the rubber O-ring is properly seated.

• Close the metal lid.
• Press the big round PUMP button.

  Pressure with flow set to 0: ~5e-2 Torr or lower.

• Place the metal cage on top of the tool.
• Open relevant precursor valves.
• Run your recipe.

  Pressure with flow present: low e-1 Torr.

  Pulse pressure: in the order of 1e0 Torr. Both precursors should show similar pulse peak pressure.

  ALD1 pulse lengths: H₂O ~0.5 s, HfOx TDMAH 0.2 s, AlOx TMA 0.02 s.

  ALD2 pulse lengths: H₂O ~0.02 s, HfOx TDMAH 0.2-0.5 s.

• Close precursor valves.
• Press the big round VENT button.
• Place the metal cage on the side of the tool.
• Take out your sample. Check the rubber o-ring.
• Press the big round PUMP button.
• Close the nitrogen bottle valve.
• Run recipe Default_heater_set.

Technical notes

• Recipe file location

  ALD1: C:\Savannah\Users\Standard\

  ALD2: C:\Cambridge Nanotech\Recipes\Standard\

• Log file location

  ALD1: C:\ALD data. Includes pressure data, screenshot at termination.

  ALD2: C:\Cambridge Nanotech\Logfile\. Includes pressure and heater temperature data, screenshot at termination, software event logs.

Troubleshooting

• Pressure reading obviously wrong (above 1e3 Torr or below 1e-4 Torr):
  • Pressure gauge failure. Unplug the network cable from the small square pressure gauge beneath the chamber and plug it back in. The pressure reading should return to expected values.
• No peak visible during precursor pulse:
  • Precursor valves closed. Make sure the relevant precursor valves are open. Consult the labels on the inside of the door.
  • Pulse time too short. Select the lowest plotting interval and check whether you can spot a small peak when the automatic valve opens. Increase pulse time as needed.
• Cannot open lid upon venting:
  • Chamber pressure still below atmosphere. Confirm pressure reading in software. If pressure is below 5e2 Torr, check whether the nitrogen bottle valve is open.
  • Rubber O-ring can get stuck to the lid. Gently but firmly lift the lid. Reseat the O-ring if needed.