Manufacture of self-aligning-type bipolar transistor

PURPOSE: To obtain the self-aligning-type bipolar structure for adoption on an SOI(silicon on insulator) substrate. CONSTITUTION: An outer base 72 is self-aligned to a side-wall oxide spacer 66 on an emitter poly 60. After the etching of the silicon on a collector side wall and the formation of a second side-wall spacer 74, a collector contact 76 is self-aligned to the outside of the emitter poly 60. By the etching of the silicon of the collector side wall, the base and the heavily doped collector contact 76 are separated. The deterioration of the breakdown voltage for the collector-base junction is blocked.