| 摘要 |
PURPOSE:To lessen the insulation capacitance between an emitter electrode and a base layer by interposing a first insulating layer, a semiconductor layer, and a second insulating layer between the emitter electrode and a base layer. CONSTITUTION:A gate oxide film 17a, a lower layer polycrystalline silicon film 18a, an oxide film 19a, and a sidewall oxide film 20a are interposed between a p-type base layer 9 and an upper polycrystalline silicon film 21a constituting an emitter electrode. Hereby, the upper polycrystalline silicon film 21a and the p-type base layer 9 are insulated from each other by the gate oxide film 17a, the lower polycrystalline silicon film 18a, and the sidewall film 20a, or the oxide film 19a. As a result, the insulation capacitance between the upper polycrystalline silicon film 21a and the p-type base layer 9 becomes small. Hereby, the parasitic capacitance between the emitter and the base becomes small. Accordingly, the drop of the operation speed of a bipolar transistor can be prevented effectively.
|
