MOS transistor breakdown phenomenon and its cause analysis

MOS transistor breakdown phenomenon and its cause analysis

MOS transistor is a common Field-effect transistor, which is a controlled semiconductor device. It has the advantages of high input impedance, low noise, low power consumption, and is widely used in electronic equipment. However, in actual use, MOS transistors may experience breakdown, leading to equipment damage. This article will introduce the phenomenon of MOS transistor breakdown and its cause analysis.

MOS transistor breakdown phenomenon refers to the phenomenon where the insulation layer of a MOS transistor is broken down when it is subjected to excessive voltage or current, resulting in a sudden increase in current and preventing the MOS transistor from working properly. The phenomenon of breakdown can cause damage to MOS tubes and even cause safety accidents such as fires. The breakdown phenomenon of MOS tubes mainly includes the following types:

Avalanche breakdown: When MOS tube is subjected to excessive voltage, electrons and holes accelerate to collide in the insulation layer, generating new electrons and holes, forming an electron Avalanche effect, which leads to the breakdown of the insulation layer.

Tunnel breakdown: When MOS transistors are subjected to excessive voltage, electrons will pass through the insulation layer, forming an electron tunneling effect, leading to the breakdown of the insulation layer.

Thermal breakdown: When the MOS tube is subjected to excessive current, heat is generated when the current passes through the MOS tube, resulting in an increase in the temperature of the insulation layer and breakdown of the insulation layer.

The main reasons for MOS tube breakdown are as follows:

Excessive voltage or current: When MOS transistors are subjected to excessive voltage or current, the insulation layer will be broken down.

High temperature: When MOS tubes operate in high temperature environments, the insulation layer's withstand voltage ability will decrease, making it prone to breakdown.

Unreasonable design: Unreasonable design of MOS tubes, such as insufficient insulation layer thickness and small electrode spacing, can also lead to the occurrence of breakdown phenomena.

To avoid the occurrence of MOS tube breakdown, the following measures need to be taken:

Select the appropriate MOS transistor: When purchasing MOS transistors, it is necessary to choose the appropriate model and parameters based on actual working conditions to avoid exceeding their tolerance range.

Control voltage and current: When using MOS transistors, it is necessary to control voltage and current to avoid exceeding their withstand range.

Optimization design: When designing MOS transistors, it is necessary to consider factors such as the thickness of the insulation layer and electrode spacing to avoid the occurrence of breakdown caused by unreasonable design.

In summary, MOS transistor breakdown is a common fault phenomenon that needs to be taken seriously. By selecting appropriate MOS transistors, controlling voltage and current, optimizing design, and other measures, the occurrence of MOS transistor breakdown can be effectively avoided, ensuring the normal operation of the equipment.