| 摘要 |
PURPOSE:To obtain a semiconductor device having large cut-off frequency and current gain by forming an N-P junction by Si or an N<+>-N or P<+>-P<++> hetero junction in contact with P-P<+> junction. CONSTITUTION:An N-type emitter 14 having several tens - thousands Angstrom is formed on a P-type base 13 on an N<->-N type collector, an amorphous N-type SiC:H layer 15 is formed thereon to form an N-N type hetero junction. Since the N-type Si layer is thin, the implantation of holes to the emitter layer 14 is prevented by the influence of a barrier due to a hetero junction boundary to increase the current gain of a transistor. Since the hetero junction and the N-P type junction boundary are separated by the N-type Si layer, the influence of a boundary level generated in the hetero junction boundary can be reduced. Since the carrier density of the N-type Si layer is decreased and thinned, the time constant between the emitter and the base can be reduced to increase a cut-off frequency.
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