METHOD OF DOPING IN DECOMPRESSED HOT WALL DEVICE

PURPOSE:To make uniform the film thickness and the specific resistance of a plurality of substrates by a method wherein doping gas is injected into a reaction tube from the opposite side of the port where a substrate jig will be put in and out. CONSTITUTION:A quartz reaction tube 2 is inserted in a diffusion furnace and a jig 3, whereon a plurality of sets of two substrates are mounted, is set at the inlet of the tube 2. Then, the jig is carried to the high-temperature reaction part in the furnace by a magnetic type automatic loader 5. Reaction gas, as the main stream of gas, is supplied through a flow meter 6 and a piping 7 and, as supplimentary gas, it is supplied through a piping 8 and a nozzle tube 11. Supplementary doping gas PH3 passes through the piping 8, the introduction tube 9 of a quartz nozzle and a manifold 10. At this point, said gas PH3 is branched into four streams, comes out of the nozzle located above the branch tubes, passes through the center of the substrate interval and injected toward the center of the circular substrate.