Chemical Vapour Deposition

Growth & Synthesis Installation 2
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CVD is a thermal process because a certain thermal energy is needed to decompose the gas precursors and reassemble them in the material to be deposited. Processing conditions in a CVD should avoid gas-phase reactions (homogenous deposition) and should favor that the deposited layer is assembled in the substrate as a surface process (heterogeneous deposition). This can be achieved at atmospheric pressure (APCVD) by heavily diluting the active gases. When these gaseous precursors are let to react in a rarefied the process is termed Low Pressure CVD (LPCVD). The partial vacuum avoids gas-phase reactions. The low pressure also favors larger diffusivity of the species so that an LPCVD process can decorate cavities and led to conformal coatings when a topography is present. The conformality is also spurred by the process temperature which favors movement of the species along the surface. Pressures are usually in the millitorr-torr range and temperatures range from 400-800C (depending on the energy needed to decompose the gas precursors). PECVD is a particular form of CVD that takes place in vacuum but in which a plasma is used to assist the decomposition of the gas precursors. This usually allows lowering the temperature of the process to a few hundred centigrade degrees, which can be run on less temperature resistant substrates or without setting off temperature triggered unwanted processes.


WARNING: Access to CNRS temporarily not available, but the technique is available at the other sites

          provided at NFFA-Europe laboratories by:

PECVD - MicroSys 200 (706)

Plasma enhanced deposition of SiNx, SiOx, Si

Process gases Ar, SiH4, NH3, N2, O2, NF3, N2O

Deposition at 20-300° C

Deposited film thicknesses typically 20-300nm

Up to 4” wafer

Turbomolecular pumping



LPCVD and PECVD @ Laboratory for Micro- and Nanotechnology

LPCVD: High quality Si3N4 films

PECVD: SiO2, Si3N4, amorphous Si deposition

LPCVD furnace (SiH2Cl2+NH3)/PECVD in Oxford plasmalab 80 plus system

LPCVD: High temperature furnace @ 780°C

PECVD: Plasma vacuum chamber, Tmax=400°C

LPCVD: Up to 4" wafers

PECVD: 4" wafers or chips


CVD and PECVD @ Analytical Laboratory

Growth of carbon-based materials

Process gases: C2H2, CH4, O2, H2, inert gasses (N2, Ar, …) - ECR reactor, COPRA

Flux: 1-100sccm

Sample temperature: RT-1500°C

Sample dimension: 1.2mm x 0.6 mm

Sample holder compatible with several other CNR-IOM laboratories (including STM, IPES, BACH beamline)

UHV system (base pressure:~10-10mbar)

The CVD system is directly connected to the following instrumentation, for in situ analysis:
- XPS and UPS analysis chamber, equipped with a conventional X-ray source Mg Ka, He discharge lamp, hemispherical electron energy analyser (120 mm by PSP)
- low energy electron diffraction (LEED)
- supersonic cluster source (AMPHIRO)
- UHV evaporators
- residual gas analyser
- sputter-gun


Semi Engineering LPCVDs  

Deposition of LPCVD high quality layers of silicon nitride and polysilicon

Quartz tubes and heaters for LPCVD thermal processes up to 800ºC

Precursors: high purity gases: Silane, DCS, NH3 and N2

Si3N4 deposition around 800ºC and polysilicon deposition between 550ºC - 650ºC

Deposited film thicknesses between 30nm-3 mm for polysilicon and between 30nm-600nm for nitride

Manual placing in vertical position in a quartz carrier onto an automatic boat loader

Wafers up to 4”

Isolated chips allowed with restrictions

Substrates with metals or polymers NOT allowed

10 mTorr range base pressure

High temperature up to 600ºC/800ºC

Clean room class 100 ambient

Semi-amorphous polySi deposition for microsystems applications

RTA or diffusion furnaces for post-deposition annealing and/or doping

Optical microscope, reflectometer and ellipsometer for film thickness measurement, confocal microscope


PECVD AMAT P5000 and Oxford Plasmalab800  

Plasma enhanced deposition of SiNx, SiOx and amorphous Si


Reaction chambers under vacuum with plasma RF source (13,56MHz) and LF source (Plasmalab: 50-460KHz) for PECVD process below 400ºC

Precursors: Silane, NH3, N2O, H2, TEOS, TMPi, TMB, O2 and N2

RF power up to 1,2 kW (Amat)/600W(Plasmalab)

LF power up to 500W(Plasmalab)

Deposited film thicknesses between 30 nm -3 mm for SiOx, between 30 nm -1.5 mm  for SiNx and between 30 nm -300 nm for a-Si 

Automatic wafer cassette loading

Plasmalab: manual positioning on the bedplate

All in horizontal position

Samples and wafers up to 6”

Substrates with polymers NOT allowed

AMAT: substrates with CMOS contaminant metals (alkalines or noble metals) NOT allowed

10 mTorr - 5 Torr range pressure

Temperature range: 200ºC – 430ºC

TEOS based SiOx doped with B and P for BPSG or PSG deposition

RTA or diffusion furnaces for post-deposition annealing

Optical microscope, reflectometer and ellipsometer for film thickness measurement, confocal microscope