| 摘要 |
PURPOSE:To obtain a compound semiconductor crystal reduced in both impurity content and number of defects, by melting a III-V family compound semiconductor polycrystal, and drawing up a single crystal from the melt while vaporizing the V-family element. CONSTITUTION:After a vessel 2 is evacuated, a cock 14 is closed, and As 13 on each of shelves 12 is heated as at 7' to sublime. Ga is placed in a crucible 1 and heated to 1,238 deg.C as at 7''. As a result, GaAs is formed on the surface of a Ga melt 9 and gradually increases in amount to become the main body of the melt 9. A seed crystal 15 is brought into contact with the melt 9 and then drawn up. In this case, As vapor is supplied from the upper side to baffle the vapor pressure of As dissociating from the molten GaAs thereby to prevent the melt composition from deviating from its stoichiometric composition. It is to be noted that an independent heater 7''' for the intermediate region is adapted to effect a precise temperature control at the interface between the liquid phase and the solid phase, thereby to conduct seeding, necking, diameter control and so forth. This constitution makes it possible to grow a single crystal reduced in both contamination and number of crystal defects due to thermal strain. |
