| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor device with easy flow of a tunnel current, with low pn-junction capacitance, and with a high cut-off frequency.SOLUTION: A semiconductor device includes: a first semiconductor layer of a first conductivity type; a second semiconductor layer of a second conductivity type; and a third semiconductor layer and a fourth semiconductor layer of the first conductivity type that are formed between the first semiconductor layer and the second semiconductor layer, and the layers are connected in the order of: the first semiconductor layer, the third semiconductor layer, the fourth semiconductor layer, and the second semiconductor layer. The band gap of the third semiconductor layer is formed narrower than the band gap of the first semiconductor layer, and the band gap of the fourth semiconductor layer is formed narrower than the band gap of the third semiconductor layer. |
