Understanding MOSFET Principles and Common Failure Modes

However, MOSFETs are prone to several failure modes:

1. Avalanche Breakdown: Occurs when the drain-source voltage (VDS) exceeds the device’s rated breakdown voltage (BVDSS), often due to voltage spikes from inductive loads or parasitic oscillations. For example, in flyback converters, unclamped inductive energy can cause VDS to surge beyond safe limits.

2. Gate Oxide Breakdown: Overvoltage or electrostatic discharge (ESD) can damage the fragile oxide layer, leading to gate leakage or short circuits. ESD events, common during handling, can inject high-energy electrons through the oxide, causing permanent damage.

3. Thermal Runaway: Excessive power dissipation from high currents or inadequate heat sinking leads to thermal stress. This can trigger a positive feedback loop where increased temperature raises resistance, further increasing power loss.

4. Body Diode Failure: In bridge topologies, the parasitic body diode may fail due to repetitive reverse recovery or overcurrent during freewheeling.

To mitigate these issues, designers should implement voltage clamping (e.g., TVS diodes for ESD protection), optimize thermal management, and ensure proper gate drive circuitry. For example, using gate resistors can dampen parasitic oscillations and reduce switching stress.

YFW Microelectronics’ MOSFETs are engineered with robust oxide layers and advanced packaging to enhance reliability in harsh environments. Our products undergo rigorous testing to ensure compliance with industry standards, providing customers with high-performance solutions for power conversion and control applications.

For more technical resources, visit www.yfwdiode.com.