Changes in Au-GaAs Schottky barrier diodes with low neutron fluence

Guarded Au/n-GaAs Schottky barrier diodes fabricated from epitaxial and bulk material with carrier concentrations of 2.2×1016 and 7.8×1016 cm−3, respectively, were exposed to fast neutron fluences between 3.6×1014 and 2.2×1015 neutron/cm2. The forward I-V and 1-MHz C-V characteristics remained relatively unchanged after irradiation at the lower fluences where carrier compensation is small (reduction in carrier concentration less than 15%). However, the reverse current increased by more than one order of magnitude at room temperature, which is neither a result of surface leakage (prevented by the guarded device structure used), classical generation-recombination current (depletion volume changes are too small), nor thermionic emission (too weak a temperature dependence). This increase in reverse current is attributed to enhanced field emission from traps.