Nature Of Traps Responsible For The Memory Effect In Silicon Nitride

Nature of traps responsible for the memory effect in Si3N4 still remains the subject matter of much discussion. Based on our quantum chemical simulation results, Si-Si bonds can be identified as traps for electrons and holes with localization energies falling within the ranges of W-t(e) = 1.2 similar to 1.7 eV and W-t(h) = 0.9 - 1.4 eV. Within the multiphonon trap ionization model, our experimental data on Si3N4 conductivity have allowed us to evaluate the thermal ionization energies of electron and hole traps in Si3N4 as W-t(e) = W-t(h) = 1.4 eV. The same value of 1.4 eV was obtained as half the Stokes shift of the 2.4 eV green photoluminescence line observed in Si3N4 films under excitation with 5.2 eV. Thus, the data obtained in the present study strongly suggest that Si-Si bonds are responsible for localization of electrons and holes in Si3N4. Published by AIP Publishing.