| 摘要 |
A logic circuit is formed of an I2L cell structure in which a difference of switching speeds at every collectors in a multi-collector structure is small. In a semiconductor device in which an integrated injection logic cell including a constant current source transistor and a switch transistor is formed on a common semiconductor substrate, a first semiconductor layer (13) doped with a first conductivity type impurity and a second semiconductor layer (19) doped with a second conductivity impurity are electrically isolated from each other on a semiconductor substrate. A plurality of collector electrodes of the switch transistor and a plurality of collector regions (20) based on diffusion of impurity are formed by the second semiconductor layer (19). The first semiconductor layer (13) includes a base electrode deriving portion, and a direct contact portion which directly contacts with the semiconductor substrate between a plurality of collector regions (20). An external base region (17) is formed by diffusion of first conductivity type impurity from the direct contact portion.
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