| 摘要 |
PURPOSE:To obtain a super-high speed bipolar semiconductor device having a base comprising a very thin, excellent single crystal silicon with high impurity concentration, by using a reverse conductivity type single crystal silicon layer in a reverse conductivity type silicon semiconductor epitaxy layer, which is formed on substrate, as a base, and using reverse conductivity type polycrystalline silicon layer as a base lead-out electrode. CONSTITUTION:An n-type silicon semiconductor epitaxy layer 1A having a thickness of about 1 mum is formed on a silicon semiconductor substrate 1 by a vapor phase epitaxy method. An element isolating insulating layer 2 is formed by a selective thermal oxidation method with a silicon nitride film as a mask. Boron is diffused so as to obtain a (p) type and a silicon semiconductor epitaxy layer 7 is grown by applying a VPE method. A part of the epitaxy layer 7, which is formed on the epitaxy layer 1A, becomes a p-type single crystal silicon layer 7S. A part, which is formed on the insulating layer 2, becomes a p-type polycrystalline silicon layer 7P. Then, impurity ions are implanted through an opening 5A, which is formed in an insulating layer 5, and an n<+> type emitter region 6 is formed. In this constitution, the n-type polycrystalline silicon layer 7P acts as a base lead-out electrode.
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