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abrowaqas
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Why there is sudden increase in the small reverse saturation current at the breakdown voltage in PN-junction Diode?
marcusl said:The phenomenon is called "breakdown" because the junction is literally broken. A typical failure mechanism when the applied voltage gets too big is equivalent to an arc through the junction, resulting in localized crystal melting. This in turn puts a low resistance "short" in parallel with the junction, giving rise to large current flow.
PN-junction breakdown is a phenomenon that occurs in a PN-junction diode when the applied reverse voltage exceeds a certain threshold value, resulting in a sudden increase in reverse current.
PN-junction breakdown is caused by the electric field created when a reverse voltage is applied to the PN-junction diode. This electric field can be strong enough to cause the bonds between the atoms in the junction to break, resulting in a sudden increase in reverse current.
The two types of PN-junction breakdown are Zener breakdown and avalanche breakdown. Zener breakdown occurs in heavily doped diodes, while avalanche breakdown occurs in lightly doped diodes.
PN-junction breakdown can cause damage to the diode, as the sudden increase in reverse current can generate excessive heat and cause the diode to fail. This can also result in a permanent decrease in the diode's ability to function properly.
PN-junction breakdown can be prevented by selecting a diode with a higher breakdown voltage, using a series resistor to limit the reverse current, and ensuring that the diode is not subjected to excessive voltage or current. Additionally, using a diode with a higher power rating can also help prevent breakdown.