Abstract: A method for growing single crystals of a dissociative compound semiconductor which are pulled in an atmosphere of a gas of a volatile component of the dissociative compound filled in an inner chamber sealed within a growth apparatus is provided wherein the space of the inner chamber is divided into different parts by means of partition wall, which is disposed in the inner chamber and the lower part of which is immersed in a melt contained in a crucible, thereby high quality single crystals with a correct stoichiometric composition can be grown under the constant conditions of temperature and pressure without detrimental effects due to thermal convection in the crystal growth region and the melt. The partition wall may be made either of a monolithic structure or a composite structure capable of being divided into two parts, an upper member and a lower member like a float, the upper part of the lower member is vertically movably inserted into upper member.

Abstract: The present invention provides a method for growing single crystals of a dissociative compound by pulling with a volatile component gas of the dissociative compound sealed at a controlled pressure in a heated growth chamber in which the single crystals are pulled, wherein a partition pipe having a lower density than the density of melt of the dissociative compound is disposed so as to immerse its lower end in the melt and the melt is covered with B.sub.2 O.sub.3 at either one of the inside or outside of the partition pipe. The method of the present invention enables the precise, appropriate control of the melt composition during the course of growing and thereby provides single crystals free from any detrimental contamination and undesirable dislocation problems. The thus obtained crystals are especially desirable for use as substrates for high speed and/or optical devices, because of their excellent semi-insulating properties.