| 摘要 |
PURPOSE:To obtain a uniform streamline flow by arranging an auxiliary tube which decreases the sectional area thereof gradually to be less than one-half in a gas flow direction between the crystal growth zone of a reaction tube and an outlet of a gas. CONSTITUTION:An auxiliary tube 36 is inserted between the substrate 33 for crystal growth and a gas outlet 35. The auxiliary tube having a conical shape is made of quartz and is placed at a low temperature side lower by 50-100 deg.C than substrate temperature at the time of crystal growth. As the result, a suddenly cooled gas at a furnace end portion can be separated from a counter flow part to a reaction tube. On the other hand, since the sectional area decreases gradually, the streamline flow is not disordered on the upper side of the auxiliary tube, and the flow of the gas is not changed and not influenced by the substrate of the crystal growth. |
