| 摘要 |
PURPOSE:To obtain an element having short base-length, low resistance, and small junction capacitance by exposing a base layer by etching respective layers with the exception of an emitter part after forming collector, base and emitter layers and by causing a base electrode taking out layer having the same conductivity type as that of the base to perform an epitaxial growth. CONSTITUTION:Layers of collectors 2 and 3, a base 4, and emitters 6 and 7 are formed in advance and after an insulating film 11 is formed on the above layers, only a part corresponding to the emitter layer is left as it is and the others are etched and further, the base layer 4 is exposed by dry-etching the emitter layer. The insulating film 11' is formed on the above base layer and only the insulating film 11' located at the upper port of the exposed base layer 4 is removed by dry-etching, and then this device allows a semiconductor layer 5 having the same conductivity type as that of the base to grow at the upper part of the exposed base layer 4 with an epitaxial glowth technique, thereby holding a space between its layer 5 and the emitter as it is. Thus a structure having exceedingly short and low base-length and small junction capacitance is obtained by maintaining the ease of taking out the base electrode as it is.
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