Semiconductor device

摘要

A Schottky barrier diode in which a p⁺-type semiconductor layer is provided in an n^--type epitaxial layer can realize lowering the forward voltage VF without considering leak current IR. However, when compared with a normal Schottky barrier diode, the forward voltage VF is generally high. When a Schottky metal layer is suitably selected, although the forward voltage VF can be reduced, there is a limit in further reduction. On the other hand, when the resistivity of the n^--type semiconductor layer is reduced, although the forward voltage VF can be realized, there is a problem that breakdown voltage is deteriorated. In a semiconductor device of the invention, a second n^--type semiconductor layer having a low resistivity is laminated on a first n^--type semiconductor layer capable of securing a specified breakdown voltage. P⁺-type semiconductor regions are made to have depths equal to or slightly deeper than the second n^--type semiconductor layer. By this, in a Schottky barrier diode in which leak current IR can be suppressed by pinch off of a depletion layer, the forward voltage VF can be reduced and the specified breakdown voltage can be secured.