| 摘要 |
PURPOSE:To enable pressure-reduced gaseous phase diffusion to be performed and to form high concentration diffused layer uniformly, by poviding an exhausting port at one end of a furnace core tube which is inserted in a heating furnace body, providing an opening part to which a cap can be attached at the other end, and providing a gas introducing port in the vicinity of the opening. CONSTITUTION:The exhausting port 6 is provided at one end of e.g. th quartz furnace tube 2 which is inserted into the furace body 1 and connected to a vacuum pump. the opening part 7 through which wafers are enclosed is provided at the other end of the furnace core tube 2. The inside of the tube 2 is kept at a pressure reduced state by the cap 3 through which drawing rod 4 is inserted in hermetically sealed state. The gas introducing port 8 is provided in th vicinity of the opening part 7 on the side of the furnace core tube 2, and desired gas can be supplied in the tube. A boat 9 on which e.g. BN plates 11 and the wafers 10 are mounted is enclosed in said furnace core tube 2, and B2O3 is predeposited under the pressure reduced state at a low temperature. Then very small amount of oxygen is introduced and a B glass layer is formed. Thereafter, treatment is performed in the reduced pressure atomosphere at a high temperature, and a shallow B diffused layer with high concentration is uniformly formed on each wafer. |
