METHOD OF CLASSIFICATION OF NATURAL DIAMOND CRYSTALS Russian patent published in 2001 - IPC

FIELD: classification of natural diamonds with low content of nitrogen; applicable in selection of integral crystals and wafers suitable in manufacture of active and passive members of semiconductor devices of microelectronics. SUBSTANCE: method includes illumination of crystal with plane-polarized light with wave length within 400-800 nm, measurement with the aid of polarizing microscope and photometric device of luminance of interference color in position of crossed nicols in transmitted light; determination of specific optical anisotropy P; placement of crystal into resonator chamber of SHF plant; radiation of crystal with radiation source; determination of SHF signal - diamond photoconductivity; comparison of these two measurements and selection of crystals. Prior to placement of crystal into resonator chamber of SHF plant, luminance of interference color is measured, specific optical anisotropy P is determined in relative units by comparison with standard specimen, where Pst-1 equals 1 relative unit with luminance of interference color of 0.1x10^-4 cd/sq.m with subsequent selection of crystals with P less than or equal to 6 relative units, intensity of SHF signal Jmax - photoconductivity is measured within wave length of 245-195 nm reduced to amplification factor K and area S of measured surface of crystal, and J^SHF= Jmax/KS is determined. Crystals with signal intensity J^SHF larger that or equal to intensity of signal of standard specimen Jst-1, where Jst-2 is maximum value for standard specimen with Pst-1 equalling 6 relative units. Besides, selected additionally are diamonds with P less than or equal to 300 relative units placed into resonator chamber of SHF plant again, and SHF signal intensity - photoconductivity is measured on at least two surfaces of crystal or wafer, crystals with maximum value J^SHF are selected and other surfaces are marked as unsuitable. EFFECT: higher yield of good natural diamonds for formation on their base of semiconductor structures uniform in electrophysical characteristics over entire volume of crystal or wafer and also semiconductor structure in layer near to surface. 2 tbl, 1 ex