| 摘要 |
PURPOSE:To obtain a hetero junction diode with a high-speed switching characteristic and high breakdown voltage and low series resistance, by forming an n-type layer into a two-layered structure and decreasing the thickness of the n-type layer, in which a junction functioning as a Potential barrier to a hole is formed, in a range where a tunnel effect does not occur. CONSTITUTION:A semiconductor with a large band gap Eg is generally high in resistivity. Therefore, when a diode is composed of such semiconductors as this, a forward voltage drop is enlarged. In order to remove this phenomenon, a n-type layer is formed into such two-layered structure consisting of a n<+> layer 4 and a n<+> layer 5. Namely, when thickness d2 of a region B functioning as a potential barrier to a hole is made smaller than thickness d1 of the n<+> layer 5, a series resistance value of the n-type layer can be decreased. The region B can be made thin to such a degree that a tunnel effect on the hole does not occur, so that even the thickness d2 of 100 nm or less is practically effectual.
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