filterprice posted an update 2 weeks, 6 days ago
Reverse breakdown can be divided into Ziner breakdown and avalanche breakdown according to the mechanism. In the case of high doping concentration, the covalent bond structure in the barrier region is destroyed due to the small width of the barrier region and the large reverse voltage, which makes the valence electrons break away from the covalent bond bond bond and produce electron-hole pairs, resulting in a sharp increase of current. This breakdown is called Zener breakdown. If the doping concentration is low, the barrier width is wide, and Ziner breakdown is not easy to occur.
Another kind of breakdown is avalanche breakdown. When the reverse voltage increases to a larger value, the external electric field accelerates the electron drift speed, thus colliding with the valence electrons in the covalent bond, knocking the valence electrons out of the covalent bond and generating new electron-hole pairs. The newly generated electron-hole is accelerated by the electric field and then knocks out other valence electrons. The carrier avalanche increases, resulting in a sharp increase in current. This breakdown is called avalanche breakdown. No matter what kind of breakdown, if its current is not limited, it may cause permanent damage of PN junction.Generator Rectifier Diode