Semiconductor and Metal Related
- Nucleation and growth of dislocations is a known mechanism for degradation of the active region, where the radiative recombination occurs. This requires a presence of an existing defect in the crystal and is accelerated by heat, high current density, and emitted light. Gallium arsenide and aluminium gallium arsenide are more susceptible to this mechanism than gallium arsenide phosphide and indium phosphide. Due to different properties of the active regions, gallium nitride and indium gallium nitride are virtually insensitive to this kind of defect.
- Electromigration caused by high current density can move atoms out of the active regions, leading to emergence of dislocations and point defects, acting as nonradiative recombination centers and producing heat instead of light.
- Ionizing radiation can lead to the creation of defects as well, which leads to issues with radiation hardening of circuits containing LEDs (e.g., in optoisolators)
- Metal diffusion caused by high electrical currents or voltages at elevated temperatures can move metal atoms from the electrodes into the active region. Some materials, notably indium tin oxide and silver, are subject to electromigration which causes leakage current and non radiative recombination along the chip edges. In some cases, especially with GaN/InGaN diodes, a barrier metal layer is used to hinder the electromigration effects.
- Short circuits Mechanical stresses, high currents, and corrosive environment can lead to formation of whiskers, causing short circuits.
Read more about this topic: List Of LED Failure Modes
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