Development and Up-Scaling of the hot filament process for diamond CVD

Research of hot-filament CVD technology constantly continues to provide new scientific developments that are transferred into economically functioning products. This business model enabled the establishment of the worldwide largest experimental CVD facility.

Development details:

• Upscaling of the hot-filament diamond surface area up to 10.000cm².
• Flexible chamber set up to coat small (weight < 1 g) as well as large components (weight > 40 kg) via CVD.
• Reduction of energy input (electric power/carat) for hot-filament CVD.
• Homogenisation of diamond growth rate and boron doping for a 2D and 3D substrates.
• Reproducible substrate temperature ranging from 650 °C to 950 °C.
• Integration of heat treatment during the hot-filament process.
• Development of in-situ measurements, e.g. online measurement of diamond growth rate.

• Ramakrishnan R., Lodes M., Rosiwal S., Singer R.:
  Self-supporting nanocrystalline diamond foils: Influence of template morphologies on the mechanical properties measured by ball on three balls testing
  In: Acta Materialia 59 (2011), p. 3343-3351
  ISSN: 1359-6454
  DOI: 10.1016/j.actamat.2011.02.009
• Hirmke J., Rosiwal S., Singer R.:
  Monitoring oxygen species in diamond hot-filament CVD by zircon dioxide sensors
  In: Vacuum 82 (2008), p. 599-607
  ISSN: 0042-207X
  DOI: 10.1016/j.vacuum.2007.09.002
• Hirmke J., Glaser A., Hempel F., Stancu GD., Röpcke J., Rosiwal S., Singer R.:
  Improved flow conditions in diamond hot filament CVD-Promising deposition results and gas phase characterization by laser absorption spectroscopy
  In: Vacuum 81 (2007), p. 619-626
  ISSN: 0042-207X
  DOI: 10.1016/j.vacuum.2006.08.004
• Hirmke J., Schwarz S., Rottmair CA., Rosiwal S., Singer R.:
  Diamond single crystal growth in hot filament CVD
  In: Diamond and Related Materials 15 (2006), p. 536-541
  ISSN: 0925-9635
  DOI: 10.1016/j.diamond.2006.01.003
• Glaser A., Rosiwal S., Singer R.:
  Chemical vapor infiltration (CVI) - Part II: Infiltration of porous substrates with diamond by using a new designed hot-filament plant
  In: Diamond and Related Materials 15 (2006), p. 49-54
  ISSN: 0925-9635
  DOI: 10.1016/j.diamond.2005.07.010