Chemical Process of Diamonds and CVD Methods

Abstract

Many times, first-order kinetics can be seen in gas-phase decomposition events. However, it is now known that such reactions are actually governed by bimolecular processes. Bimolecular collisional activation to an energy sufficient for decomposition sets off the reaction. Gas-phase processes occurring in catalytic cycles are also to blame for the development of the ozone hole in the polar stratosphere in the spring, albeit heterogeneous mechanisms must also be taken into account. A chemical process called a "gas evolution reaction" is one of which a gas, like oxygen or carbon dioxide, is among the byproducts. When the resulting gases are explosive or dangerous when inhaled, gas evolution reactions can be performed in a fume chamber. To achieve considerable diamond growth rates, gas-phase activation must occur above the deposition surface. In order to induce gas-phase activation, the various CVD techniques differ primarily from one another. Methyl radicals and acetylene molecules are the most prevalent carbon-containing gaseous species found in most activated systems, and they are also regarded as the main growth precursors for diamond, essentially regardless of the deposition techniques employed. But acetylene is not the only carbon atom that is plentiful in the gas phase in systems that dissolve a large portion of H2, such DC plasma arc-jet CVD. Several energctically aided CVD techniques are developed and used to achieve the gas-phase increase in efficiency necessary for the stable development of well-crystallized diamond