| 摘要 |
<p>A high-cut-off frequency, high-speed HBT is obtained by suppressing the diffusion of impurities to the utmost by lowering a heat treatment temperature in the step subsequent to the formation of a high concentration base layer (5). A base electrode (15) for a base layer (5) is made of a metal or an intermetallic compound which extends the emitter layer (6) to reach at least a part of the base layer (5). The metal or intermetallic compound forms Schottky barrier with an emitter layer (6) having a wide forbidden width ,and ohmic contacts with the base layer (5) with a narrow forbidden band. The barrier potential of the Schottky junction formed between the intermetallic compound or metal and the emitter layer (6) is higher than the diffusion potential of a pn junction between the base layer (5) and the emitter layer (6). <IMAGE></p> |
