Specific Process Knowledge/Thin Film deposition/ALD/Al2O3 deposition using ALD

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The ALD window for depostion of aluminium oxide ranges from 150 ^oC to 350 ^oC. XPS measurements shows that at temperatures below 150 ^oC the Al₂O₃ layer will be contaminated by unreacted TMA molecules, and at temperatures above 350 ^oC the TMA decomposes.

All results shown on this page have been obtained using the "AL2O3" recipe on new Si(100) wafers with native oxide:

Recipe: AL2O3

Temperature: 150 ^oC - 350 ^oC

	TMA	H2O
Nitrogen flow	150 sccm	200 sccm
Pulse time	0.1 s	0.1 s
Purge time	3.0 s	4.0 s

The deposition rate for Al₂O₃ depends on the temperature, see the graph below.

Al2O3 deposition rate as function of temperature.

In the graphs below the Al₂O₃ thickness as function of number of cycles for deposition temperatures between 150 ^oC and 350 ^oC can be seen. From the equations the number of cycles required for a certain thickess can be calculated.

• Aluminium oxide thickness as function of number of cycles
• 
  Temperature 150 ^oC.
• 
  Temperature 200 ^oC.
• 
  Temperature 250 ^oC.
• 
  Temperature 300 ^oC.
• 
  Temperature 350 ^oC.

Evgeniy Shkondin, DTU Danchip, February-March 2014.