Method to eliminate the surface growth defects of large single crystal diamonds: an effective solution to improve the utilization rate for commercial production

In this work, a growth defect with bowl shaped pits has been found to form during the growth of a diamond, synthesized over a long period of time using the temperature gradient growth (TGG) method under high pressure and high temperature (HPHT) conditions. The experimental results show that the defect arises during the later growth stage of the diamond synthetic process. In order to explain the formation of the defect, the temperature and convection fields in the later growth state of the catalyst have been analyzed using the finite element method (FEM). The formation mechanism of the growth defect on the diamond crystal has been explained accurately by the simulated results and a good agreement has been obtained between the calculated results and the observed experimental data. Exhilaratingly, we propose a simple and efficient method to eliminate growth defects by adjusting the catalyst thickness. This method not only can improve the quality of large single crystal diamonds, but also may be helpful in reducing the cost of diamond cutting in the commercial market.