PURPOSE: To control a rate of emitter diffusion properly and to control depths of an internal base diffused layer and emitter diffused layer with good reproducibility, by implating second dopant ions for forming a second dopant diffused layer of one conductivity type into a second polycrystalline semiconductor film before implating third dopant ions for forming a third dopant diffused layer of the reverse conductivity type into a third polycrystalline semiconductor film through an insulating film.
CONSTITUTION: As+ ions 21 for forming an emitter diffused layer 23 are implanted into a poly-Si film 20 through an SiO2 film 19, after implanting B+ ions for forming an internal base diffused layer 14 into a poly-Si film 17. Accordingly, when a P-type Si substrate 11 is heat-treated, the As+ ions 21 are caused to pass through the SiO2 and poly-Si films 19 and 17 and to reach an N-type epitaxial layer 12. In this manner, the emitter diffused layer 23 is formed after the formation of the internal base diffused layer 24.
TANDO YASUHIKO
MIYAKE TSUNEHITO
FUJITSU VLSI LTD
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