| 摘要 |
PURPOSE:To stabilize product characteristics by adjusting the flow rate of a supply gas by the difference of a set value signal corresponding to the flow rate of a gas to be fed into a reaction furnace and an output signal corresponding to the flow rate of a carrier gas passing through an evaporation regulator. CONSTITUTION:Voltage VM outputted from a voltage conversion circuit 6 in response to the set flow value Ml/min of H2 gas to be fed to a reaction furnace 1 is inputted to an arithmetic circuit 11. Output voltage VC corresponding to the flow rate Cl/min of carrier H2 gas introduced to a vaporizer controller 5 is also inputted to the circuit 11. The difference of voltage VM and VC is outputted to a mass flow controller 2, and the flow rate of main H2 is adjusted. The flow rate of SiCl4 gas in a mixed gas from a vessel 4 is regulated by set value voltage VS outputted from a voltage conversion circuit 7 in response to a flow set value Sg/min in a controller 5. Accordingly, the ratio of both gases is kept constant at all times in the reaction furnace 1, thus stabilizing the characteristics of an silicon epitaxial layer formed through vapor growth in the reaction furnace 1.
|
