| 摘要 |
<p>A bipolar transistor comprising an emitter, a base, and a collector wherein the band gap of at least a partial region of the base is narrower than the band gap of the emitter. The base has a first layer disposed adjacent to the emitter with a band gap narrower than the band gap of the emitter and a second layer disposed adjacent to the first layer with a band gap narrower than the band gap of the first layer. This bipolar transistor improves advantages in device manufacture, that is, uniformity, yield, and productivity while keeping the peak values of a cutoff frequency and a maximum oscillation frequency equivalent to those of a base structure with an ideal compositional gradient.</p> |
