Thermal breakthrough

The thermal break is one of three breakdown mechanisms in semiconductor devices . The semiconductor loses its characteristic property of being able to block and becomes conductive. Three different breakthrough mechanisms can be identified:

1. Avalanche breakthrough (cause: impact ionization),
2. Zener breakthrough (cause: tunnel effect),
3. Thermal breakdown (cause: heating of the semiconductor).

Since semiconductors have finite track resistances, heat loss occurs when current flows , an effect that is similar to friction . Excessive heating of the semiconductor leads to its destruction. This effect is therefore irreversible .

Two causes can cause large heat losses:

• In river operation: too large currents
• In blocking mode: voltages too high