Synthesis of large-size β-Si3N4 crystals

Large-sized beta-Si3N4 crystals up to 10 mm in length and 0.3 mm in diameter with low impurity concentration are successfully grown from silicon melt in a nitrogen atmosphere, By controlling the concentration of impurities in the silicon melt, a new kind of beta-Si3N4 crystal, that is, a transparent coloring one with an absorption edge around a wavelength of 520 nm, is obtained.