| 摘要 |
PURPOSE:To form a shallow impurity diffusion layer having high surface impurity density by a method wherein a solidstate diffusion source and a silicon wafer are quickly heated up simultaneously in a vacuum state using a lamp annealing device, the temperature is raised to the target temperature by stages in two or more stages, impurities are diffused on the wafer, they are cooled down, nitrogen is made to flow at the same time, and the impurities are discharged. CONSTITUTION:The atmospheric air containing moisture is brought into the quartz tube 5, the nitrogen to be used to prevent the change of B2O3 density on the surface of a boron plus plate 10 is allowed to flow, and the quartz tube 5 is airtightly sealed by a chamber door 7. A silicon wafer 11 is placed in the tube 5, the tube 5 is heated up while it is being evacuated to +mTorr, the above-mentioned state is maintained until the surface temperature of the boron plus plate 10 and the silicon wafer 11 is made uniform. Besides, their temperature is raised to the prescribed diffusion temperature by heating them for several seconds, and the prescribed diffusion layer is obtained. When the heat treatment is finished, the evacuating operation is stopped, nitrogen is made to flow, temperature is dropped, and after the above-mentioned state is maintained for several tens of seconds, they are quickly cooled down to the room temperature. |
