Diamond Crystallinity Research Articles

Formation and characterization of diamond crystals synthesized by microwave plasma CVD system

Abstract Diamond crystals have been successfully synthesized on (100) Si wafer using microwave plasma CVD. The growth was conditioned in a flowing system in which the parameters, such as CH4/H2 ratio, pressure, temperature and microwave power were varied. Cubo‐octahedra or tetrakaidecahedra are the equilibrium shape of diamond single crystals obtained under all conditions and are therefore the basic unit for the formation of polycrystalline diamond films, mostly through repetitive twinning and secondary growth of diamond crystals on {100} habit planes of cubo‐octahedra. Both X‐ray diffraction and Raman spectroscopy were used to facilitate the analysis of the diamond crystallinity and purity. These qualities are similar to those of natural diamonds.

Crystallinity and strength of diamond bombarded with low energy ion beams

In order to improve the performance of diamond tools formed or sharpened with Ar ions, we have used RHEED to investigate the crystallinity of diamond specimens machined with argon ions of 0.4–2.0 keV and processed with hydrogen plasma (ions and atoms) at 800–850° C under various conditions. Moreover, the microstrength of diamond specimens machined with Ar ions and processed with hydrogen plasma has also been investigated by Hertz indentation. The damaged layer of the diamond specimen caused by Ar ion bombardment can be removed by processing with hydrogen plasma. Moreover, the microstrength of a diamond specimen prefinished by conventional mechanical lapping (39 GPa) is decreased to 34 GPa by bombardment with argon ions. However, that is increased to 47 GPa by processing with hydrogen plasma.