Patent ID: 7964280
Filing Date: 2011-06-21
Classification: C23C,C30B,Y10T

Abstract:
1. A method of forming a CVD diamond, the method comprising: (i) providing a substrate; (ii) providing a CVD synthesis atmosphere in which there exists a gas comprising nitrogen at a concentration greater than 300 ppb, calculated as molecular nitrogen; and (iii) adding into the CVD diamond synthesis atmosphere a gas comprising boron or silicon, wherein the boron or silicon is added in a controlled manner into the CVD diamond synthesis atmosphere to reduce a detrimental effect on color of the single crystal CVD diamond caused by nitrogen so as to produce a single crystal CVD diamond in which a majority volume of at least 80% of the single crystal CVD diamond has at least one of the following features (a) to (e): (a) an absorption spectrum measured at room temperature such that the color of a standard 0.5 ct round brilliant would be better than K on the Gemological Institute of American (GIA) gem diamond color scale; (b) an absorption coefficient at 270 nm measured at room temperature which is less than 2.9 cm (c) an absorption coefficient at 350 nm measured at room temperature which is less than 1.5 cm (d) an absorption coefficient at 520 nm measured at room temperature which is less than 0.45 cm (e) an absorption coefficient at 700 nm measured at room temperature which is less than 0.18 cm wherein the single crystal CVD diamond has a thickness of greater than 0.1 mm, wherein a concentration of nitrogen in the majority volume of the single crystal CVD diamond is greater than 5×10