Specific Process Knowledge/Thin film deposition/Deposition of Niobium Titanium Nitride

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Deposition of Niobium Titanium Nitride

Deposition of NbTiN can be done by reactive sputtering.

The preferred tool for this application is the Cluster-based multi-chamber high vacuum sputtering deposition system, commonly referred to as the 'Cluster Lesker.' The operating process is thoroughly documented and described in detail.:

Comparison of LPCVD, PECVD, and sputter systems for silicon nitride deposition

LPCVD PECVD Sputter-System Metal-Nitride(PC3) and Sputter-System Metal-Oxide(PC1) Lesker sputter system
Generel description
  • Low Pressure Chemical Vapour Deposition (LPCVD furnace process)
  • Plasma Enhanced Chemical Vapour Deposition (PECVD process)
  • Reactive sputtering
  • Pulsed DC reactive sputtering
  • Reactive HIPIMS (high-power impulse magnetron sputtering)
*Reactive sputtering
Stoichiometry
  • Stoichiometric nitride, Si3N4
  • Silicon rich (low stress) nitride, SRN
  • SixNyHz
  • SixOyNzHv

Silicon nitride can be doped with boron or phosphorus

  • SixNy (Sputter-System Metal-Nitride(PC3))
  • SixOyNz (Sputter-System Metal-Oxide(PC1))

Tunable composition

  • Unknown
Film thickness
  • Stoichiometric nitride: ~5 nm - ~230 nm
  • Silicon rich (low stress) nitride: ~5 nm - ~335 nm

Thicker nitride layers can be deposited over more runs (maximum two)

  • ~40 nm - 10 µm
  • limited by process time.
  • Deposition rate likely faster than Sputter-System (Lesker)
  • limited by process time.
  • Deposition rate ~ 1-5 nm/min
Process temperature
  • Stoichiometric nitride: 780 °C - 800 °C
  • Silicon rich (low stress) nitride: 810 °C - 845 °C
  • 300 °C
  • Up to 600 °C
  • Up to 400 °C
Step coverage
  • Good
  • Less good
  • some step coverage possible, especially by HIPIMS
  • some step coverage possible but amount unknown
Film quality
  • Deposition on both sides og the substrate
  • Dense film
  • Few defects
  • Deposition on one side of the substrate
  • Less dense film
  • Incorporation of hydrogen in the film
  • Deposition on one side of the substrate
  • Less dense film
  • Properties including density tunable (requires process development)
  • Deposition on one side of the substrate
  • unknown quality
  • likely O-contamination
KOH etch rate (80 oC)
  • Expected <1 Å/min
  • Dependent on recipe: ~1-10 Å/min
  • Unknown
  • Unknown
BHF etch rate
  • Unknown
  • Unknown
Batch size
  • 1-15 100 mm wafers (4" furnace), 1-25 100 mm wafers (6" furnace)
  • 1-25 150 mm wafers (only 6" furnace)
  • Several smaller samples
  • 1-7 50 mm wafers
  • 1 100 mm wafers
  • 1 150 mm wafer

Depending on what PECVD you use

  • many smaller samples
  • Up to 10*100 mm or 150 mm wafers
  • Several smaller samples
  • 1-several 50 mm wafers
  • 1*100 mm wafers
  • 1*150 mm wafer
Allowed materials
  • Silicon
  • Silicon oxide
  • Silicon nitride
  • Pure quartz (fused silica)

Processed wafers have to be RCA cleaned

  • Silicon
  • Silicon oxide (with boron, phosphorous)
  • Silicon nitrides (with boron, phosphorous)
  • Pure quartz (fused silica)
  • III-V materials (in PECVD4)
  • Small amount of metals (in PECVD3)
  • Almost any as long as they do not outgas and are not very toxic, see cross-contamination sheets
  • Any