Radiation-induced displacement damage in silicon carbide blue light-emitting diodes

The effect of electron irradiation on the minority carrier lifetime of silicon carbide (SiC) light-emitting diodes has been evaluated. It is shown that the frequency-domain lifetime measuring technique used on GaAs LEDs (light emitting diodes) can be used successfully on SiC devices to determine a unique value for damage constant at energies not too close to threshold. Although the electron threshold energy for displacement damage is lower than that for GaAs by a factor of 2.5 because of the smaller mass of the carbon atom, at energies above 0.5 MeV the damage constant for SiC is more than three orders of magnitude lower than for GaAs, indicating greatly superior performance in most radiation environments. Preliminary annealing studies indicate significantly different recovery behavior for damage by electrons of different energies.<
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