MANUFACTURE OF HIGH SPEED BIPOLAR TRANSISTOR

PURPOSE:To easily manufacture a high speed bipolar transistor by forming a narrow emitter having a narrow pattern width by an ordinary self-alignment without using a special device and a special process and making an emitter electrode close to a base electrode. CONSTITUTION:After a polycrystalline silicon layer 6 is etched except a base electrode, an SiO2 film 7 is formed about 3000Angstrom -1.5mum thick on the surface by a normal pressure CVD using monosilane. Then, the whole film 7 is etched until the film 7 at the thinner emitter part than the other part is eliminated by RIE, a base Si3N4 film 5 and an SiO2 film 3 are removed by etching, a polycrystalline silicon layer is formed on the whole surface, As or P is implanted from above to form a polycrystalline silicon emitter electrode 8. Thus, an emitter layer 9 is narrower than the emitter region pattern removed by etching from the layer 6 to be largely reduced.