Role of Copper in the Degradation of GaAs Electroluminescent Diodes

Abstract

The degradation associated with prolonged operation of GaAs diodes under large forward bias has been investigated. It is observed that the degradation rate increases with temperature and that the fractional percent degradation per unit time interval increases as exp (−E₀/KT) for most devices. The value of E₀ is about 0.45 ± 0.1 eV. It is shown that contamination of devices with copper increases the degradation rate. The 1.28‐eV emission band in the degraded Cu‐contaminated devices is enhanced relative to the band‐edge emission at low temperatures. A Cu‐contamination model for the degradation is considered which shows agreement with experimental data. Accordingly, the degradation is attributed to the diffusion of interstitial copper ions in the p region of the devices toward the junction during operation at high‐current densities.