VACUUM VAPOR PHASE GROWTH DEVICE

摘要

PURPOSE:To perform safe operation with a titled device using dangerous gas by throttling one end of a reaction tube and passing the gas to a gas outflow pipe forming the double construction on the outside thereof thereby reducing the pressure in the reaction tube and diluting quickly the waste gas after the reaction. CONSTITUTION:A gaseous raw material of a group III element is introduced into a vessel 6 and the alkylated compd. of the group III element contained therein is supplied in the form of vapor to a reaction tube 101 in the case of growing the crystal of a group III-V compd. semiconductor by, for example, an MOCVD method. On the other hand, a gaseous raw material of a group V element is supplied from a cylinder 1 to the tube 101 and these gaseous raw materials are thermally decomposed on a substrate 10 to grow the crystal on the substrate 10. The vapor growth is accomplished under the reduced pressure in this case in order to eliminate the disturbance in the growth of an intermediate product. N2 of the inert gas of which the flow rate is controlled by a flowmeter 103 is passed through a piping 104 and is admitted at a high speed into the gas outlet pipe 102 provided on the outside of the tube 101 so as to make the tube double-fold for the purpose of the above-mentioned growth. Then the inside of the tube 101 is reduced by the effect similar to the effect of a venturi pipe and since there are no electrical systems as in a vacuum pump, the operation is safe and the danger is prevented owing to dilution of the gas.