| 摘要 |
PURPOSE:To remove the amount of dispersion of current amplification factor and eliminate the need for making apertures twice at an emitter region, thereby, improving an integration degree and decreasing the total man-hour as well, by carrying out an emitter diffusion after completion of a process where a base region of a metal layer such as aluminum and the like is flattened. CONSTITUTION:A highly concentrated n-type buried layer 2 is formed on a substrate 1 and a collector region 3 is formed by causing an n-type silicon layer to make an epitaxial growth. A base 7 is formed by introducing p-type impurities and a thin insulating film 8 is formed after removing a silicon nitride film used in a LOCOS process from a collector electrode region. A PSG film 11 is formed to 6000 Angstrom thickness and is treated with heat at a temperature of around 1000 deg.C. As a result, the PSG film 11 is flattened and apertures for an emitter diffusion as well as for a collector- contact diffusion are formed. Then, polycrystal silicon layers 9 are formed on the above apertures and an n-type region 101 and an emitter 10 are formed by passing through the polycrystal silicon layers 9 and also by diffusing n-type impurities. After removing the PSG film 11 as well as the thin insulating film 8 from a base electrode- contact region and also after forming a base electrode-contact aperture, an aluminum film is formed and it is processed by patterning.
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