Croissance de monocristaux de bore rhomboédrique β par une méthode de type verneuil

Abstract

β-rhombehedral boron crystals are grown from the melt, at about 2100°C, without crucible, by a modified Verneuil process. A molten pool is created on the tip of a vertical boron rod (12 mm in diameter) by means of a cylindrical rf heating coil: 1 MHz, 2.5 turns, 12 mm in external diameter, 12–15 mm high. Boron powder is slowly fed into the liquid while the growing crystal is rotated and pulled downwards at a rate of 1 to 10 cm h -1. Growth may occur either on a graphite pedestal or on a boron seed: 〈0001〉 is a preferential growing direction.