Characterization and Deposition Methods and Classification of CVD Diamond

The CVD diamond film is mostly composed of dense polycrystalline diamond grain, generally used to be analyzed and characterized by scanning electron microscopy, Raman spectrometry and X-ray. X-ray diffraction will be used to test the orientation of diamond, and the half height of Raman peaks is related to the grain boundary, dislocation, crystal defects and microtwins and other crystal defects in the diamond crystals. Generally, these crystal defects can make the half height of Raman characteristic peak of diamond film increased.

At present, countries around the world have developed more than 20 methods of low pressure gas phase synthesis of diamond film. One is PVD (physical vapor deposition) technology represented from the chemical vapor deposition method and sputtering method, whose characteristic is: low air pressure and temperature, and no H2. It is the primary method of amorphous diamond, diamond-like carbon, and hydrogen carbon film, but has not synthesised single phase diamond film so far; The other is CVD (chemical vapor deposition) technique with method of hot filament, which is applied more widely in the development of industry.

Chemical vapor deposition methods mainly include: common chemical vapor deposition method, hot filament CVD method (HCVD), plasma chemical vapor deposition (PCVD) method (including direct current plasma chemical vapor deposition (DC-PCVD), radio frequency (RF) plasma chemical vapor deposition (RF-PCVD), microwave plasma chemical vapor deposition (MW-PCVD) and plasma jet, the flame combustion method, etc.

Physical vapor deposition methods include sputtering method, chemical vapor phase transport method, material beam deposition method, etc. The most widely used and mature in these methods are hot filament CVD method and dc plasma jet chemical vapor phase method.