| 摘要 |
PURPOSE:To reduce a parasitic capacitance between a collector and a base by a method wherein a transistor active region (genuine base region, emitter region) is formed in a self-matching manner and moreover an oxide film is formed also in a self-matching manner on an underside of an outer base region connected with a genuine base region. CONSTITUTION:Boron(B<+>) ions 5X10<15>/cm<2> in density are implanted with 40KeV through a resist film 27 and a Si3N4 film 24 serving as masks for the formation of a P-type exterior base region 28. Furthermore, oxygen ions (O2<+>)1X10<19>/cm<2> in density are implanted with 180KeV for the formation of a SiO2 film 29 under the exterior base region 28. Oxydization is performed through the Si3N4 film 24 serving as a mask for forming SiO2 film 30. A base electrode window is formed where the Si3N4 24 is removed and a polycrystalline Si film 31 is formed on the whole surface. Boron ions(B<+>) are selectively implanted to form the genuine base region 32 and render a contact of the base electrode ohmic as well. Moreover, arsenic ions(As<+>) are selectively implanted for the formation of an emitter region 33.
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