Specific Process Knowledge/Thin film deposition/ALD Picosun R200/HfO2 deposition using ALD

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The ALD temperature window for HfO2 is 150 - 300 ^oC.

The TEMAHf precursor is heated to 125 ^oC (TE210) and the heater (TE211 max.) is set to 140 ^oC during deposition. Remember to set the values in the "MANUAL" tab and to change them to back after deposition (TE211 max. to 1 ^oC). These values may not be exceeded to prevent precursor decomposition. Due to the heating of the precursor the stabilization time needs to be set to 60 min. Else an alarm (TE210 PID limit exceeded while pulsing) will be triggered and the process will be stopped after the first pulsing attempt.

HfO₂ standard recipe

HfO₂ deposition using TEMAHf and H₂O precursors

The following tables show the recipe and boost settings for the TEMAHf precursor:

	TEMAHf	H2O
Nitrogen flow	150 sccm	120 sccm
Pulse time	1.6 s	0.1 s
Purge time	8.0 s	4.0 s

Boost flow	500 sccm
Pre-empty	0.5 s
Master fill	1.2 s
Post-empty	0 s

HfO₂ deposition at 150 ^oC

Two HfO₂ depositions were made January 2018 - One for 91 cycles and one for 250 cycles. Both deposition were done on 4" wafers with native oxide. The deposition temperature was 150 ^oC , and the precursor temperature (T210) for TEMAHf was 125 ^oC.

Number of cycles: 91

Results:

Average HfO₂ thickness: 9.57 nm (measured in nine points)
Deposition rate: 0.11 nm/cycle
Non-uniformity: 4.15 %

• 
  Ellipsometer measurement of HfO₂. Deposition temperature: 150 ^oC. Number of cycles: 91.

Number of cycles: 250

Results:

Average HfO₂ thickness: 27.65 nm (measured in five points)
Deposition rate: 0.11 nm/cycle
Non-uniformity: 2,20 %

• 
  Ellipsometer measurement of HfO₂. Deposition temperature: 150 ^oC. Number of cycles: 250.

HfO₂ deposition at 250 ^oC

The test was done with 300 cycles at 250 ^oC where the deposition rate was measured to be 0.0827 nm/cycle. The precursor temperature (T210) for TEMAHf was 125 ^oC.

• 
  Ellipsometer measurement of HfO₂. Deposition temperature: 250 ^oC. Number of cycles: 300.

Parameter	Average	Min.	Max.	Std.Dev	%Range
Thickness (nm)	24.83	24.05	27.13	0.68	12.38

• 
  AFM measurement roughness 0.3784 nm.

The XPS measurement was made by our XPS-ThermoScientific and shows that the film is purely HfO₂ except for some impurities on the surface.

• 
  Atomic percentage distribution of a depth profile.

Tanja Amport, Pernille Voss Larsen and Mikkel Dysseholm Mar, DTU Danchip, 2017.