Question

Avalanche breakdown is primarily dependent on this phenomenon of collision.Explain.

Answer 1

Avalanche breakdown usually occurs when we apply a high reverse voltage across the diode. So as we increase the applied reverse voltage, the electric field across junction will keep increasing. This generated electric field exerts a force on the electrons at junction and it frees them from covalent bonds. These free electrons will gain acceleration and it will start moving across the junction with high velocity. This results in collision with other neighboring atoms. These collisions in high velocity will generate further free electrons. These electrons will start drifting and electron-hole pair recombination occurs across the junction. This results in net current that rapidly increases.