| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a bipolar transistor wherein a lead base electrode can be connected to an epitaxial silicon layer in a low damage process in a simple and convenient manner. SOLUTION: In forming a base/emitter, damage of a surface of the epitaxial silicon layer 3 by etching can be eliminated by stopping dry etching of a silicon oxide film 11 and thereafter wet etching the film. Further, deformation of a polysilicon film 12 as a lead base electrode can be enhanced by heating the film at an ultra-high vacuum level (of 1×10-4 to 1×10-5 Pa). As a result, self alignment enables the base electrode to be connected to the silicon layer 3. A part 18 contacted with the silicon layer 3 is formed to have an eaves structure due to the above wet etching, so that the contact area of the part 18 with the base electrode can be made large and thus a base resistance can be reduced.
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