SIMULATED GROWTH-PROCESS OF SINGLE-CRYSTAL DIAMOND AT HIGH-PRESSURE

The diffusion field of carbon is calculated for the molten metallic so lvent in the temperature gradient growth system of diamond. The surfac e of the growing crystal gives carbon concentration on it as a part of the boundary conditions. The calculated concentration gradient on the surface produces the growth rate of the surface, which determine a ne w surface, a new boundary condition, for the next step calculation of the concentration distribution. The features of the calculated diffusi on field can predict substantial natures of particular growth systems very well, and explain several phenomena accompanied with the growth p rocess. The relations between the crystal weight and growth time are r eproduced with different characters according to the geometry of the g rowth space. Quantitative agreement with observed experimental results is excellent if the process parameters are properly selected. The pre sent simulation has revealed the existence of an important character o f the growth process such as the growth rate peak, which has not been noticed so far and is considered to be related to formation of metalli c inclusions in the crystal.