The electrical conduction processes through silicon nitride are examined and discussed. Three processes were found to occur: Frenkel–Poole emission, field ionization, and trap hopping. The characteristic constant for the field ionization was found to be lower than expected (~5 × 106 V cm−1), and the thermal activation energy for the trap hopping was between 0.08 and 0.10 eV. The Frenkel–Poole effect indicated trap depths varying from 0.50 to 0.85 eV for various devices, and was more complicated than previously reported. All of the processes were bulk limited. Approximate values of m*/m and the mobility at 300 °K were found to be 0.20 and 0.13 cm2/V s respectively.