meltback

Meltback is a phenomenon observed in certain semiconductor devices, particularly during periods of high electrical stress or overcurrent. It occurs when the intense heat generated by the current flow causes the semiconductor material itself to melt. This melting can lead to a permanent degradation or failure of the device.

The process begins with localized heating within the semiconductor. This can be due to a defect in the material, poor contact, or simply exceeding the device's rated current capacity. As the temperature rises, the silicon or other semiconductor material reaches its melting point. Once melted, the molten material can flow, often creating a short circuit or an open circuit depending on how it solidifies. This molten state is irreversible and renders the component non-functional.

Meltback is a critical failure mode that engineers strive to prevent through careful device design, material selection, and operating condition management. Understanding the thermal characteristics and current limits of semiconductor devices is essential for avoiding meltback failures. It is distinct from thermal runaway, which involves a self-reinforcing cycle of increasing temperature and conductivity, though meltback is often the ultimate consequence of severe thermal runaway.