| 摘要 |
PURPOSE:To form an emitter region in a highly accurate manner by a method wherein after an epitaxially grown Si layer, having the prescribed pattern, has been formed in advance on the part where an emitter region will be formed, the Si layer is removed using the etchant consisting of KOH. CONSTITUTION:On the emitter forming region marked out with an interelement isolation insulating film 27, a film of two-layer structure of prescribed pattern consisting of a silicon dioxide film 28A and a silicon nitride film 29A is formed on an N-type Si epitaxial layer 21. Then, after an Si layer 30 has been epitaxially grown on the surface, an external base region 31 is formed by ion implantation with boron atoms. Subsequently, a silicon nitride film 32 is formed on the layer 30 excluding the external base forming region of the layer 21, and the layer 30 is oxidized by heat using the film 32 as a mask. Then, the film 32 on the emitter forming region is removed, the layer 30 located below the layer 32 is removed using the aqueous solution of KOH, and an aperture part is formed on the emitter region.
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