| 摘要 |
PURPOSE:To enable the shallowing of a base layer, by reducing the amount of implanted base impurities by utilizing the characteristic of a self-aligning transistor. CONSTITUTION:An oxide film 12, a silicon nitride film 13 and a polycrystalline Si layer 14 are connected in superposition on the surface of an Si substrate 11, and B is diffused in high concentration into the layer 14. Next, an oxide film 15 and a silicon nitride film 16 are formed on the surface of the layer 14. The films 16-14 in a region in which an emitter is to be formed are removed. An oxide film 17 is formed on the lateral side of the film 14. Then, base impurities in an amount of 4X10<13>cm<-2> or less are implanted to form a base layer 18. A polycrystalline Si layer 19 is connected thereafter, and photoetching is applied by using a pattern larger than an emitter mask. The films 15-17 are removed. Then, the exposed film 12 is removed. The layer 19 in the emitter region is removed. When the exposed film 12 is removed, a base contact region 2 can be formed. A polycrystalline Si layer 20 is connected thereafter, and when heat treatment is applied thereto, B is diffused from the layer 14 into the layer 20. After B is diffused in the lateral direction, the layer in which B is not contained is subjected to etching. Then, an emitter layer 1 is formed.
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