| 摘要 |
PROBLEM TO BE SOLVED: To reduce leakage current of a bipolar transistor by suppressing formation of crystal defects in structural portions, such as sidewalls which have large stress concentration. SOLUTION: This method of manufacturing a bipolar transistor having a double polysilicon structure uses a polycrystalline silicon film as lead-out electrodes in the emitter region 11 and the base region (the external base region 9 and the intrinsic base region 10). For the formation of the region 9, it is subjected to a long duration heat treatment at a low temperature of about 600 deg.C as a first annealing step after the polycrystalline silicon film is doped with an impurity, and then to a short duration heat treatment at a high temperature of about 1,000 deg.C as a second annealing step.
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