| 摘要 |
PURPOSE:To eliminate variations of high frequency characteristics caused by the differences in distances between emitter windows and base contact windows by forming the emitter windows and the base contact windows simultaneously. CONSTITUTION:After base regions 9 and 10 are formed in a semiconductor substrate 8, a silicon nitride film 11 is formed and emitter windows 12 and base contact windows 13 are formed in the silicon nitride film 11 with a single photomask. Then, a silicon oxide film 12 is formed over the whole surface and apertures, which are wider than the emitter windows 12 mentioned above, are formed in the silicon oxide film 12. Then polycrystalline silicon layers 14 doped with impurity are formed in the apertures and subjected to a heat treatment to form emitter regions 15. Then, after the silicon oxide film 12 is removed, the base contact windows 13 mentioned above are drilled again and base electrodes 17 and emitter electrodes 16 are formed on the base contact windows 13 and the polycrystalline silicon layers 14 mentioned above.
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