Characteristics and Properties of Diamond

The compact structure of diamond accounts for its outstanding properties. It is the hardest of all materials with the highest thermal conductivity. It is the most perfectly transparent material and has one of the highest electrical resistivities and, when suitably doped, is an outstanding semiconductor material. The properties of CVD and single-crystal diamonds are summarized in Table 7 2.[1][18]-[20] 

Diamond is obtained as a polycrystalline material by CVD with properties similar to these of natural diamond. Efforts to produce single crystal thin films have so far been largely unsuccessful. 

A basic reaction in the CVD of diamond is based on the decomposition of a hydrocarbon, such as methane, as follows  

The deposition is a complex mechanism which is not fully understood at this time. Two conditions seem necessary (a) activation of the carbon species and (b) the action of atomic hydrogen. These factors are reviewed in the following sections. 

Deposition Precursors. Diamond has been deposited from a large variety of precursors which include, besides methane, aliphatic and aromatic hydrocarbons, alcohols, ketones, and solid polymers such as polyethylene, polypropylene, and polystyrene, and halogens. 

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