| 摘要 |
PURPOSE:To increase the operating speed and enhance the collector withstand voltage by a method wherein, with the thickness of a low concentration collector layer set in a specific range, this layer and a base layer are formed of hetero kinds of semiconductor, and the band gap of the collector layer is made larger than that of the base layer. CONSTITUTION:A high concentration collector layer 12, the low concentration collector layer 13, base layer 14, and an emitter layer 15 are successively formed on a substrate 11. A region for base electrode formation is formed by partial exposure of the base layer, and a region for collector electrode formation is formed by partial edposure of the collector layer 12. Finally, an emitter electrode 16, a base electrode 17, and a collector electrode 18 are formed. When the thickness LCI of the collector layer 13 is 0.03-0.2mum, the cut-off frequency fgamma can be increased, and the operating speed can be increased. Then, when the mixed crystal ratio (x) is determined (x>0.45) so that the band gap (b) at the point X may become smaller than that (a) at the point gamma, the band gap of the low concentration collector layer can be made smaller; accordingly, the collector withstand voltage can be made higher. |
