Avalanche breakdown also is used intentionally in semiconductors to serve as a trigger element to initiate turn-on of an ESD circuit. Avalanche breakdown plays a key role in semiconductor ESD elements and circuits which are intentionally reverse biased during
functional operation of semiconductor chips, but are initiated at a voltage above the native
operational voltage. This phenomenon is key to ESD networks in MOSFET and bipolar devices. It is utilized on input pin circuits, between common power rails in ESD power clamps, and between power rails. Hence, it is fundamental to the ESD discipline. What is the avalanche process? Avalanche breakdown occurs when a carrier is accelerated by an electric field, where the collision with the material leads to a secondary carrier (Figure 1.4). The secondary carrier is then also accelerated, forming a third interaction. This is why it is called “avalanche multiplication.”
Avalanche breakdown plays an important role in the understanding of electrostatic discharge issues.