| 摘要 |
PROBLEM TO BE SOLVED: To improve a frequency responsibility of a transistor, especially a vertical PNP transistor, in other words, to increase a cut-off frequency fT, in the manufacture of a semiconductor device including a bipolar transistor having a high cut-off frequency. SOLUTION: A P-type diffusion layer serving also as a side face collector region of a vertical PNP transistor is formed by vertically etching an N-type epitaxial layer which constitutes the vertical PNP transistor. Then, the P-type diffusion layer is formed on its side wall with an oxide film and then is filled with high melting point metal. The side face collector region itself is reduced in resistance and its width and diffusion depth, which have been expanded in a thermal diffusion, are not expanded. As a result, a parasitic capacity of the diffusion layer of the side face collector region is reduced and a collector capacity is also reduced as a whole, increasing a cut-off frequency fT of the vertical PNP transistor.
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