Specific Process Knowledge/Thin film deposition/PECVD

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PECVD Plasma Enhanced Chemical Vapor Deposition

Name PECVD4: PRO CVD
Vendor: SPTS

PECVD3 - positioned in cleanroom A-1, photo: DTU Nanolab internal
PECVD4 - positioned in cleanroom B-1, photo: DTU Nanolab internal

We have two PECVD's here at DTU Nanolab. They can both be used to deposit Silicon oxides and Silicon nitrides with or without dopants of Boron and Phosphorus. PECVD3 can also deposit thin layer of aSi. PECVD3 is used for silicon based processing with small amounts (<5% wafer coverage, under some condition even more) of metals where as PECVD4 is dedicated for clean wafers both for silicon based materials and III-V materials. Quartz carriers are used in PECVD4 and they are dedicated the two different material groups to avoid cross contamination. See the precise rules in the equipment manuals which are uploaded in LabManager.

PECVD is a chemical vapor deposition process that applies a plasma to enhance chemical reaction rates of reactive species. PECVD processing allows deposition at lower temperatures, which is often critical in the manufacture of semiconductors. PECVD films are however known for not being stochiometeric and normally a lot of hydrogen is incorporated inside the films.

All though PECVD4 and 3 are very similar you should not expect to transfer a recipe between the systems and get the exact same result.

The user manuals, quality control procedures and results, user APVs, technical information and contact information can be found in LabManager (requires login):

PECVD3 in LabManager
PECVD4 in LabManager

Process information on PECVD3 and PECVD4





Overview of the performance of PECVD thin films and some process related parameters

PECVD PECVD3 PECVD4
Purpose Deposition of dielectrica
  • Silicon oxide
  • Silicon nitride
  • Silicon oxynitride
  • BPSG (Boron Phosphorous doped Silica Glass)
  • aSi
  • Silicon oxide
  • Silicon nitride
  • Silicon oxynitride
  • BPSG (Boron Phosphorous doped Silica Glass)
Performance Film thickness
  • ~10nm - 30µm
  • ~10nm - 30µm
Index of refraction
  • ~1.4-2.1
  • ~1.4-2.1
Step coverage
  • In general: Not so good
  • BPSG: Floats at 1000oC
  • In general: Not so good
  • BPSG: Floats at 1000oC
Film quality
  • Not so dense film
  • Hydrogen will be incorporated in the films
  • Not so dense film
  • Hydrogen will be incorporated in the films
Process parameter range Process Temperature
  • 300 oC
  • 300 oC
Process pressure
  • ~200-900 mTorr
  • ~200-900 mTorr
Gas flows
  • SiH4:0-180 sccm
  • N2O:0-3000 sccm
  • NH3:0-1000 sccm
  • N2:0-3000 sccm
  • GeH4:0-6.00 sccm
  • 5%PH3:0-60 sccm
  • 3%B2H6:0-1000 sccm
  • SiH4:0-60 sccm
  • N2O:0-3000 sccm
  • NH3:0-400 sccm
  • N2:0-3000 sccm
  • Ar:0-1000 sccm
  • He: 200sccm
  • 5%PH3:0-100 sccm
  • 3%B2H6:0-850 sccm
Substrates Batch size
  • One 4" wafer per run
  • One 6" wafer per run
  • Or several smaller pieces on carrier wafer
  • Deposition on one side of the substrate
  • One to 7 2" wafer per run
  • One 4" wafer per run
  • One 6" wafer per run
  • Or several smaller pieces
  • Deposition on one side of the substrate
Materials allowed
  • Silicon wafers, Quarts (fused silica) wafers
    • with layers of silicon oxide or silicon (oxy)nitride
    • Other material (can be allowed if less than 3.9 cm2 is exposed to the plasma (<5% coverage of a 4" wafer), please ask!
  • Silicon wafers, Quartz (fused silica) wafers,
    • with layers of silicon oxide or silicon (oxy)nitride
  • III-V wafers (on special carriers)