Specific Process Knowledge/Thin film deposition/Deposition of Alumina

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Deposition of Al2O3

Aluminium oxide (Alumina, Al2O3) can be deposited by use of ALD (atomic layer deposition), by e-beam evaporation or by sputtering. During the evaporation or sputter deposition oxygen is added to the chamber resulting in aluminium oxide on the sample.

Comparison of the methods for deposition of Alumium Oxide

Sputter-System(Lesker) Sputter-System Metal-Oxide(PC1) ALD Picosun 200 10-pocket e-beam evaporator
Generel description
  • RF sputtering from Al2O3 target
  • Reactive sputtering
  • RF sputtering from Al2O3 target
  • Pulsed DC reactive sputtering
  • Reactive HIPIMS (high-power impulse magnetron sputtering)
  • ALD (atomic layer deposition) of Al2O3
  • E-beam evaporation of Al2O3 pellets or of Al in an O2 flow
Stoichiometry
  • Not tested
  • Not tested
  • Al2O3, very good
  • Not tested yet
Film Thickness
  • few nm - 200 nm
  • few nm - 200-300 nm
  • 0nm - 100 nm
  • few nm - 200 nm (talk to staff if you wish to deposit more than 100 nm as it can cause flaking in the chamber)
Deposition rate
  • 0.3 nm/min
  • About 1.7 nm/min, depends on sputtering parameters
  • 0.088 - 0.097 nm/cycle (Using the "Al2O3" recipe, temperature dependent)
  • 1-2 Å/s
Step coverage
  • unknown
  • unknown
  • Very good. Covers sample everywhere (but long purge time needed for very high aspect ratio structures)
  • We expect no step coverage unless using tilt holder, in which case the step coverage can be very good and can be tuned.
Process Temperature
  • room temperature
  • Up to 600 °C
  • 150 °C - 350 °C
  • Up to 250 °C
More info on Al2O3
Substrate size
  • chips
  • 1x 100 mm wafer
  • 1x 150 mm wafer
  • chips
  • 10x 100 mm wafer
  • 10x 150 mm wafer
  • 1-5 100 mm wafers
  • 1-5 150 mm wafers
  • Several smaller samples
  • chips
  • 1-3 x 100 mm wafers
  • 1-3 x 150 mm wafers
  • 1-3 x 200 mm wafers
Allowed materials
  • almost any that does not degas
  • Silicon
  • Silicon oxide, silicon nitride
  • Quartz/fused silica
  • Al, Al2O3
  • Ti, TiO2
  • Other metals (use dedicated carrier wafer)
  • III-V materials (use dedicated carrier wafer)
  • Polymers (depending on the melting point/deposition temperature, use carrier wafer)