In semiconductors, insulation breakdown occurs in the insulating layer or PN junction due to surges or short-term high voltages, and is one of the causes of failure in semiconductor devices.

Principle of insulation breakdown

• Surge breakdown occurs when a momentary high voltage pushes the insulating material (e.g., silicon dioxide, polyimide, epoxy, etc.) or PN junction of a semiconductor beyond its withstanding limit.

• Avalanche breakdown and Zener breakdown are representative examples. Avalanche breakdown occurs when electrons are accelerated by a high-frequency electric field, dislodging other electrons within the lattice, resulting in a surge in current. Zener breakdown occurs in highly doped diodes when electrons tunnel under a strong electric field at low voltage.

Major types of damage

• Pinhole formation in insulating layers such as silicon oxide films → Increased leakage current in the long term, leading to gradual failure.

• PN junction insulation breakdown in semiconductors → loss of device function, heat dissipation, and additional damage as large amounts of current flow.

• Arcing and leakage current within multilayer insulation within PCB or integrated circuit → Gradually deteriorating insulation, which can lead to fatal open/short failure.

Typical conditions of occurrence

• Lightning and switching surge : A momentary high voltage of tens to hundreds of kV is applied when the breakdown threshold is exceeded depending on the silicon oxide film thickness, insulator quality, and joint type.

• Accumulation of repetitive voltage stress : possible degradation of insulation durability, long-term aging, and fatigue failure.

Protection and Prevention

• Install surge protection devices (SPDs) : Block transient voltages and reduce the risk of insulation breakdown.

• Increase insulation thickness and apply high-quality insulation materials when designing devices : Thick insulation materials (e.g., 400 μm polyimide) can withstand up to 10 kV.

• Design of an arc/voltage distribution structure within the device : Minimizes thermal and electrical effects caused by repetitive surges and arcs.

Reference Table (Examples of Destruction Methods and Thresholds)