Meaning
Failure mode where a non-conductive layer loses its insulating properties and allows a sudden surge of current. Studying oxide film breakdown helps engineers determine the maximum safe operating voltage. This transition from insulator to conductor is usually permanent and destructive.
Dielectric Stress
High electric fields pull electrons through the atomic structure of the material. The oxide film breakdown occurs when the field strength exceeds the dielectric strength of the oxide. This process often starts at a single point of weakness, such as a lattice defect or a contaminant particle, and quickly spreads.
Thermal Runaway
Current flowing through the breakdown path generates heat, which further reduces the resistance of the material. Oxide film breakdown leads to a localized melting of the dielectric and the surrounding metal electrodes. This thermal spike can cause the entire package to rupture or catch fire if the current is not limited by external circuitry.
Testing Limit
Accelerated aging tests are used to predict the time to failure under normal operating conditions. The oxide film breakdown voltage is measured by ramping the potential until the leakage current reaches a predefined threshold. Devices that show early signs of breakdown are screened out during the manufacturing process to ensure long-term reliability.