Growth of large size high quality single crystal diamond

Large size (with a thickness exceeding 2mm) and high purity diamond single crystal grown by microwave plasma CVD. As per our examination, the sample color and clarity can all reach the gem grade level. With the optimization of process parameters, the crystal growth rate can reach up to 30 um/h, and the thickness tolerance of polishing sample can reach + / - 0.05 mm, crystallographic orientation deviation can reach ±2 ° and the surface roughness Ra < 30 nm.

The full width at half maximum (FWHM) of diamond (400) peak in the X-ray rocking curve is only 0.008 (left), whilst the nitrogen content in the diamond single crystal isestimated to be less than 1.1 ppm from the tiny absorption peak at 270nm (right). Diamond single crystal with nitrogen content as low as 0.7ppm (700ppb) has also beensuccessfully obtained.