| 摘要 |
PURPOSE:To improve the resistance of a base, the capacitance of a collector and the like and to improve the characteristics such as cut-off frequency, by forming a groove deeper than the contact surface of a base electrode between an emitter region and the like on a base layer and a region, where a base electrode is arranged, implanting ions in the region, where the base electrode is arranged, and in the groove, and forming an outer base region. CONSTITUTION:Before ion implantation for forming an outer base region 8, a groove 9, which is deeper than the contact surface of a base electrode 11 between an emitter (or collector) region on a base layer 4 and a region, where the base electrode is 11 is formed. Ions are implanted into a range from the region, where the base electrode 11 is arranged, to the groove 9. Therefore a part of the outer base region 8 at the groove part 9 does not become thin. A part of the outer base region 8, which is connected to the base layer 4, is shifted in the direction of the high concentration in an impurity implanting profile. Therefore, the base resistance becomes low. The area occupied by the groove 9 is very small. The distance between the outer base region 8 and a sub-collector layer 2 at a part beneath an electrode contact surface is made larger than the conventional distance. The capacitance between said parts is reduced, and the high frequency characteristics such as cut-off frequency can be improved.
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