| 摘要 |
PURPOSE:To produce a single crystal of a compound semiconductor having high decomposition pressure, in high yield and workability, by detecting the pressure in the bomb for supplying an inert gas and in the closed vessel, and controlling the feeding or discharging flow rate of the inert gas according to the detected data. CONSTITUTION:An inert gas is supplied from the bomb 15 to the closed vessel 1 in the growth of a compound semiconductor crystal having high decomposition pressure, e.g. GaP, etc. The pressure of the inert gas is controlled to keep the output level of the pressure sensor A36 at a constant level. The pressure in the vessel 1 is detected constantly during the pulling of the crystal by the pressure sensor B34, and the difference of the output signals of both sensors 34 and 36 is converted to an electrical signal by the device C37. When the pressure difference exceeds the preset level, the solenoid valve V1 (25) of the bypass discharge line 26 is opened and the inert gas is discharged from the system little by little through the needle valve V2 (27). As an alternative method, the solenoid valve V3 (31) of the bypass feed line 30 is opened, and the inert gas is supplied to the vessel 1 through the needle valve V4 (32). The lowering of the yield of a single crystal caused by the pressure fluctuation in the vessel can be prevented by this process. |
