PRODUCTION OF GAAS SINGLE CRYSTAL AND ITS APPARATUS

摘要

PURPOSE:To make the control of temp. and vapor pressure easy in comparison with a conventional method and also to prevent the impurities from mixing by providing the radiation shields of the plural steps consisting of BN or PBN between a lower part of a crucible incorporated in a closed vessel and an As source part. CONSTITUTION:The radiation shields 9 of plural steps consisting of BN or PBN are provided between a lower part of a crucible 2 incorporated in a closed vessel 1 for drawing up GaAs single crystal in a hot wall method and an As source part 4. The size of the radiation shields 9 is made a little smaller than the internal diameter of the closed vessel 1 (the clearance is regulated to about 0.5-1cm in the diameter). The thermal inflow due to the radiation from the neighborhood of the crucible is prevented by superposing the radiation shields 9 in the plural steps and also the thermal transfer due to the convection is prevented by making the clearance small between the closed vessel 1 and the radiation shields 9. Thereby both the neighborhood of the crucible 2 and the As source part 4 are thermally made almost independent and the temp. control is separately made easy.