Reliability of vapor-grown planar In/sub 0.53/Ga/sub 0.47/As/InP p-i-n photodiodes with very high failure activation energy

The mean time to failure (MTTF) was measured for a statistically significant population of planar In/sub 0.53/Ga/sub 0.47/As/InP heterostructure p-i-n photodetectors at several elevated temperatures. The probability for failure is fit to a log-normal distribution, with the result that the width of the failure distribution is sigma =0.55+or-0.2, and is roughly independent of temperature. From the temperature dependence of MTTF data, it is found that the failure mechanism is thermally activated, with an activation energy of less than 1.5+or-0.2 eV measured in the temperature range of 170-250 degrees C. This extrapolates to a MTTF of less than 0.1 failure in 10/sup 9/ h (or <0.1 FIT) at 70 degrees C, indicating that such devices are useful for systems requiring extremely high reliable components, even if operated at elevated temperatures for significant time periods. This activation energy is the highest value reported for In/sub 0.53/Ga/sub 0.47/As/InP photodetectors, and is significantly higher than the energies of approximately 0.85 eV often suspected for these devices.<
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