| 摘要 |
1,234,963. Gallium phosphide crystals. CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE. 12 June, 1968 [13 June, 1967], No. 28010/68. Heading B1S. [Also in Division C1] Material is crystallized upwardly from the base of a tube containing a solution of the material (the solute being replenished by continuous absorption of a feed consisting of the material or a constituent thereof in vaporous, liquid or solid form at the upper surface of the soltuion. A liquid feed may diffuse through a capillary. The tube is lowered through a heating zone having a low temperature gradient into a heating zone having a high temperature gradient under such conditions that the composition of the solution remains constant and crystallization always takes place at a constant temperature, within the second zone. The second zone may have a gradient of 80‹C/cm. The rate of descent may be 2-3 mm/day. A seed may be placed at the base of the tube or formed in situ within a constriction at the base of the tube. A dopant may be incorporated in the solution or feed. In the crystallization of gallium phosphide, the apparatus comprises three heating zones 3, 4 and 5, for the vaporization of phosphorus, maintaining a melt of gallium containing gallium phosphide formed by chemical reaction, and effecting crystallization of gallium phosphide, respectively. A body F of phosphorus is continuously vaporized at a desired rate from an inner tube 2 in the upper part of a tube 1 containing a melt D of gallium and is absorbed at the upper surface of the melt while tube 1 is lowered and crystallization of a body DF of gallium phosphide effected. |
