What is CVD?
A. CVD is an abbreviation for Chemical Vapour Deposition which is a crystal growth process used not only for diamond but also for a range of different semiconductor and other crystalline materials such as silicon or gallium arsenide. The technique generally involves the growth of a solid material from the gas phase using a reactive gas mixture which supplies the necessary active species (carbon in the case of diamond) onto a controlled surface (or substrate). In contrast to high pressure/high temperature (HPHT) synthesis, the CVD technique is generally performed at below atmospheric pressure. Because CVD can use very high purity reagents the technique is capable of synthesising crystals in which the purity is closely controlled. Development of CVD technology over the last decade has led to the formulation of a range of new diamond materials with properties optimised for specific applications. These include high purity CVD diamond for optical or electronic applications as well as CVD di
