COLOURLESS MONOCRYSTALLINE DIAMOND AND METHOD FOR PRODUCTION THEREOF Russian patent published in 2013 - IPC C30B25/02 C30B29/04 C23C16/27 C30B28/14 

FIELD: chemistry.

SUBSTANCE: invention relates to the technology of producing a colourless monocrystalline diamond by chemical vapour deposition (CVD), which can be used in optical and jewellery applications. The method involves preparation of a substrate, using the diamond CVD synthesis atmosphere, which contains nitrogen in concentration ranging from 300 ppb to 30 ppm, and adding gas to the synthesis atmosphere, said gas containing boron in concentration ranging from 0.5 ppb to 0.2 ppm; wherein boron is added to the synthesis atmosphere in a controlled manner so as to provide stability of boron concentration higher than 20% and in an amount selected to reduce negative effect of nitrogen on the colour of the diamond, where the dominant volume of at least 80% of the monocrystalline diamond has at least one of the following characteristics: absorption spectrum, measured at room temperature, which corresponds to colour of standard circular diamond weighing 0.5 carats better than K on the Gemological Institute of America (GIA) colour scale, and absorption coefficient, measured at room temperature at wavelength 270 nm is less than 2.9 cm^-1, at wavelength 350 nm - less than 1.5 cm^-1, at wavelength 520 nm - less than 0.45 cm^-1 and at wavelength 700 nm - less than 0.18 cm^-1. That monocrystalline CVD diamond has thickness of more than 0.1 mm; nitrogen concentration in the dominant volume of the diamond ranges from 1·10¹⁴ to 5·10¹⁷ atoms/cm³, and boron concentration ranges from 3·10¹⁴ to 1·10¹⁷ atoms/cm³.

EFFECT: invention enables to obtain a colourless or almost colourless monocrystalline diamond for making gemstones and optical devices.

15 cl, 3 dwg, 6 tbl, 9 ex