Synthesizing single-crystal diamond by repetition of high rate homoepitaxial growth by microwave plasma CVD

Repetition of high rate homoepitaxial growth of diamond by microwave plasma CVD has been successfully applied to the growth of single-crystal diamonds with the thickness as large as 10 mm. By optimizing the shape of the substrate holder, smooth and flat surface morphology suitable for regrowth has been obtained. Using this condition, a 4.65 ct single-crystal diamond with the thickness of 1 cm has been grown on a HPHT synthetic 5 × 5 × 0.7 mm3 seed by 24 times repetition of high rate growth with the average growth rate of 68 μm/h. Also a method to enlarge the size of diamond three-dimensionally by growing on side {100} surface of a thick diamond prepared by this technique has been demonstrated.