Very slow charge trapping and release in ion implanted GaAs [MESFETs]

Unusually slow trapping and release of electrons has been observed in ion implanted GaAs with room temperature time constants of the order of 1000 s. Trap filling experiments showed that the capture cross section was temperature dependent with capture being more efficient at lower temperatures. The measured capture cross sections were used to refine the analysis of the emission data to demonstrate the existence of two electron emission processes with activation energies of 0.56 eV and 0.013 eV. The effects appear not to be artefacts due to surface or interface states at the edge of the test structures but are due to states within the bulk of the semiconductor within the implanted region.