CCVD Process: Thin Films

CCVD Technology and Traditional Coating Technologies

Thin films have traditionally been deposited using CVD, PVD, or Sol-gel. Existing CVD and PVD technologies require a reaction or vacuum chamber to deposit thin films. Traditionally, CVD also requires a furnace or auxiliary heating system to further control the environment for the deposition to occur. Due to these temperature and vacuum requirements, substrates (the materials being coated) that can be used in these processes are limited. Sol-gel requires multiple deposition steps to achieve acceptable thin film thickness, with concurrent difficulties in maintaining the purity of the resultant thin film.

Traditional Coating Technologies

Technology Issues
 Chemical Vapor Deposition (CVD)
  • Difficult or impossible to deposit multi-element compounds
  • Requires expensive high temperature reaction furnace and/or vacuum environment, and expensive high vapor pressure compounds
  • Substrate must withstand high temperatures (limits choices)
 Physical Vapor Deposition (PVD)
  • Difficult or impossible to deposit multi-element compounds
  • Requires expensive high vacuum chamber
  • Substrate must be vacuum compatible (limits choices)
  • Limited to flat substrates
 Sol-gel
  • Difficult to maintain purity
  • Multi-step process (lower productivity)
  • High temperature substrates only

 nGimat’s proprietary Combustion Chemical Vapor Deposition (CCVD) process is an open-atmosphere, flame-based technique for depositing high-quality thin films and nanomaterials. A schematic representation of a CCVD system for thin film coatings and its major components is shown below compared to a traditional CVD system.

Combustion Chemical Vapor Deposition

The CCVD process is based on nGimat’s NanoSpraySM Combustion Processing technology. In the process, precursors (metal-bearing chemicals used to coat an object) are first dissolved in a solution, which typically is a combustible fuel. This solution is then atomized to form microscopic droplets by means of nGimat’s proprietary NanomiserTM Device. These droplets are next carried by an oxygen stream to the flame where they are combusted. A substrate (the material being coated) is coated by simply drawing it in front of the flame. The heat from the flame provides the energy required to vaporize the droplets and for the precursors to react and deposit on the substrate. One of the strengths of the CCVD process is the variety of deposited materials and substrates that can be utilized. The CCVD process offers significant advantages over traditional CVD/PVD techniques, including:

  • Quality production of highly-tailored and complex material solutions that cannot be commercially achieved with CVD/PVD processes;
  • Elimination of energy intensive, highly specialized and expensive equipment (e.g., vacuum chambers, reaction furnaces and chemical scrubbers);
  • Continuous manufacturing capability currently unavailable under competing CVD/PVD batch technologies; and
  • Use of low-cost and environmentally friendly precursors and other process chemicals.

Deposited Materials

This is a representative, but not complete, list of deposited materials, substrates and application areas. Many of these same materials can be deposited as nanopowders desired for any number of applications.

Metals Ceramics Others
Ag, Au, Cu, Ir, Ni, Rh, Pt, Ru, Zn Al2O3, Al2O3•MgO, 3Al2O3•2SiO2, BaCeO3, BaCO3, BaTiO3, BST, doped-CeO2, Cr2O3, CuxO, [La.95Ca.05]CrO3, Fe2O3, In2O3, ITO, LaAlO3, LaPO4, LSC, LSM, MgO, Mn2O3, MoO3, Nb2O5, NiO, NSM, PbSO4, PbTiO3, PdO, PLZT, PMN, PMT, PNZT, PZT, RbOx, RhOx, RuO2, SiO2, Spinels (e.g. NiAl2O4, NiCr2O4), Silica Glasses, SnO2, SrLaAlO4, SrRuO3, SrTiO3, Ta2O5, TiO2, V2O5, WO3, YBa2Cu3Ox, YbBa2Cu3Ox, YIG, YSZ, YSZ•Al2O3, YSZ-Ni, ZrO2, ZnO (+ dopants in many cases) Over 10 polymers (polyimides, NafionTM, epoxies), numerous composites of metals, ceramics and polymers
Substrates Used
 Al, Brass, Ag, Cu, Pt, Ni, Stainless and C-Steel, Al2O3, Fiber Tows, Glass, Graphite, LaAlO3, MgO, NafionTM, NiCr, Optical fibers, OPP, PET, Polycarbonate, Silica, Si, Si-Ti/Pt wafers, SiC, Si3N4, Superalloys, TeflonTM, Ti, TiAl alloy, YSZ, powders
 Some Applications
Adhesion, capacitors, catalytic applications, corrosion resistance, gas diffusion barriers, electronics, engines, ferroelectric materials, flat panel displays, fuel cells, interface layers, optics, piezoelectrics, resistors, RF and millimeter wave components solar cells, superconductors, thermal barrier, thermal control, and wear resistance

For additional CCVD technical information, refer to:

  • Hunt, A.T., et al. (1993, July 12). Combustion chemical vapor deposition: A novel thin-film deposition technique. Applied Physics Letters, pp. 266-268.
  • Hunt, A.T., et al., Method and Apparatus for the Combustion Chemical Vapor Deposition of Films and Coatings, U.S. Patent 5,652,021, 1997.
  • Hunt, A.T., et al., Combustion Chemical Vapor Deposition of Phosphate Films and Coatings, U.S. Patent 5,858,465, 1999.
  • Hunt, A.T., et al., Method for the Combustion Chemical Vapor Deposition of Films and Coatings, U.S. Patent 6,013,318, 2000.
  • Hunt, A.T., Pohl, M. (2001). Combustion Chemical Vapor Deposition (CCVD). In Park, J. (ed.), Chemical Vapor Deposition (pp. 81-102). Materials Park, Ohio: ASM International.