Question

Avalanche breakdown in a semiconductor diode happens when (A) forward bias exceeds a certain value (B) forward current exceeds a certain value (C) reverse bias exceed a certain value (D) the potential barrier is reduced to zero

Short answer

Avalanche breakdown in a semiconductor diode occurs when the reverse bias exceeds a certain value, as it causes a large increase in reverse current due to the acceleration of charge carriers across the junction. Therefore, the correct answer is (C) reverse bias exceed a certain value.

Step-by-step solution

Understand Semiconductor Diodes Under Various Biases

A semiconductor diode consists of a P-type material and an N-type material that are joined together, forming a P-N junction. Under a forward bias, the positive terminal of the voltage source is connected to the P-type material and the negative terminal to the N-type material, allowing current to flow easily. In reverse bias, the positive terminal of the voltage source is connected to the N-type material and the negative terminal to the P-type material, creating a high resistance to current flow. The potential barrier is the energy barrier that prevents charge carriers from crossing the junction. Step 2: Identifying the Avalanche Breakdown Condition

Identify the Avalanche Breakdown Condition

Avalanche breakdown occurs when a high reverse-biased voltage is applied to the semiconductor diode, causing a large number of charge carriers (electrons and holes) to accelerate across the junction and collide with other charge carriers, creating more charge carriers and resulting in a large increase in reverse current. Step 3: Matching the Correct Answer from the Options

Match the Correct Answer

Based on the explanations given in steps 1 and 2, it's clear that avalanche breakdown in a semiconductor diode happens when the reverse bias exceeds a certain value. Therefore, the correct answer is: (C) reverse bias exceed a certain value