| 摘要 |
PURPOSE:To turn a junction ON-OFF by extremely small voltage amplitude by a P-N junction, in which carriers are injected, crossing a potential barrier, by forming a region, which has thickness in an extent that tunnel currents are caused to flow through the P-N junction and has no impurity or low impurity concentration, between a P-region and an N-region. CONSTITUTION:An I-layer 3 to which any donor or acceptor is not doped is shaped between a semiconductor 1 (an N<+> layer), to which a P-type impurity in high concentration is doped, and a semiconductor 2 (a P<+> layer) to which an N-type impurity in high concentration is doped. The band gap of the P<+> layer is narrowed and the band gap of the N<+> layer is widened in band structure at that time. The band gap of the I layer is changed continuously to the band gap of the P<+> layer from the band gap of the N<+> layer. Si is used normally as a group III-V donor impurity and Be as an acceptor. In this case, electrons in an N<+> region and holes in a P<+> region are degenerated intensely, and Fermi levels 4 are each formed in a conduction band 5N and a valence band 6P. The conditions of such strong degeneration can be realized by sufficiently high doping.
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