| 摘要 |
PURPOSE:To form a thin base and increase the amplification factor by making a PNP lateral transistor, thereby separating parts other than a portion of self aligning structure that is coated with resist. CONSTITUTION:SiO2 films ranging from 12 to 15 are formed in sequence on a Si substrate 11 and a thermal oxide film 16 is formed at a side wall of a hole by etching SiO2 films 15 and polysilicon 14. Portions shown by slanting lines are applied with resist 17 and SiN films 13 are etched and then SiO2 films 12 are removed by etching. Resist 17 is removed so as to form polysilicon films 18. On the other hand, the polysilicon films 18 are etched and only polysilicon on the side wall are removed. The SiO2 films 19 and polysilicon 20 are formed. Once these substances are etched, a hole attaining a depth up to the surface of the substrate is formed. The hole is filled with polysilicon which is doped with N-type impurities and if it is annealed, P-type base regions 31 and an N-type emitter region 32 are formed. Eventually, Al is vaporized to form an electrode. |
