| 摘要 |
PURPOSE: A bipolar transistor and a fabrication method thereof are provided to enlarge a safe operation area by restraining local current concentration during turnoff and to reduce switching time by reducing turnoff time. CONSTITUTION: An n type epitaxial layer(13) is grown on an n+ type semiconductor layer(11) in a semiconductor substrate(10). A p type base region(15) is formed in the epitaxial layer(13) and n+ type emitter region(17) is formed in the base region(15). At an underneath junction between the emitter and base regions(17,15), a p+ type base region(16) is formed. Further, an emitter electrode(E) and a base electrode(B) are electrically connected to the emitter and base regions(17,15) through contact holes in a passivation layer(19) stacked on the epitaxial layer(13), while a collector electrode(C) is formed on the entire bottom surface of the semiconductor layer(11). In this transistor, since minority carrier flows to the emitter region(17) via the base region(16), the current concentration at local part of junction of the emitter region(17) or the base region(15) is restrained during turnoff.
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