Surge protection device

摘要

A surge protection device for absorbing surges of either polarity has a second region forming a first pn junction with a first region, a third region capable of injecting first minority carriers into the second region, a fourth region forming a second pn junction with the first region and a fifth region capable of injecting second minority carriers into the fourth region. The surfaces of the fourth region and the fifth region and a first Schottky junction with respect to the first region are in mutual electrical connection with a first ohmic electrode, while the surfaces of the second region and the third region and a second Schottky junction with respect to the first region are in mutual electrical connection with a second ohmic electrode. During the initial stage when a surge voltage applied across the first and second electrodes is in a transient rising state, the dV/dt immunity is increased by majority carrier current flowing into the first region through the Schottky junction forward biased owing to the surge polarity and charging the junction capacitance of the reverse biased pn junction.