| 摘要 |
PROBLEM TO BE SOLVED: To cope with both the cost reduction and the high frequency response characteristics of a longitudinal NPN bipolar transistor having a polysilicon emitter electrode structure, by controlling the current amplification factor of the transistor without adding any process. SOLUTION: On forming an emitter polysilicon 190 at low temperatures (400°C), an interfacial oxide film (natural oxide film) grows between an intrinsic base 140 and the emitter 190. Then the heat treating temperature for forming an emitter 150 is adjusted in a range of 820-910°C to control the interfacial oxide film condition and the pile up condition of electrons, thus finely adjusting the current amplification factor. COPYRIGHT: (C)2008,JPO&INPIT
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