| 摘要 |
<p>In a phototransistor having an emitter, a collector and a base, the impurity density of the base regions (20, 21) is irregular, a minority of carriers produced by a light are stored in the base region (20) having a large impurity density, and the majority of carriers are stored in the base region (21), with a low impurity density, in such a way that they are easily removed. The two base regions are placed in such a manner that the voltages of the base regions of large and small impurity densities are coupled to each other. This phototransistor can operate at extremely high sensitivity and high speed. </p> |
