| 摘要 |
PURPOSE:To prevent the transformation of the surface of a substrate and the deterioration of dissipation of the structure of a diffraction grating, ridge and the like on the substrate due to heat, by controlling the temperatures of the substrate and a solution independently. CONSTITUTION:An outlet port 3 is so provided that a cooling gas can be made to flow directly to a substrate holder element of a growth boat, and only the vicinity of a substrate element is cooled down. An InP substrate having a diffraction grating is set in the substrate holder element, and it is heated to a prescribed temperature and kept thereat by heaters 13, while hydrogen is made to flow together with a substitution gas and the cooling gas. On the occasion, the flow rate (f) of the substitution gas at outlet ports 3 and 10 is set at 0.4l/min and 0.6l/min respectively. After a high temperature is kept for 1hr, the substitution gas at the outlet port 10 is turned to be 1.0l/min and the quantity of gas at the outlet port 03 to be zero. These conditions are maintained for 10min, and in this period the growth is implemented. While a solution for growth is kept at a high temperature, the substrate holder unit is cooled to prevent the structure on the substrate from being deteriorated or dissipated due to heat. The cooling of the substrate holder element is stopped just before the growth is executed, so that an entire system be put uniformly under a growth temperature. Thereby the growth can be implemented with the structure on the substrate preserved, without any effect on the growth.
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