Conduction Studies in Silicon Nitride: Dark Currents and Photocurrents
by D. J. DiMaria, P. C. Arnett
Dark conduction and photoconduction phenomena in amorphous, stoichiometric Si3 N4 films incorporated into metal-silicon nitride-silicon (MNS) structures are studied in detail. Results demonstrating the importance of hole conduction in Si3 N4 thin films are presented. The importance of trapped space charge injected from the contacts is shown in an analysis of the effects of Si3 N4 thickness and the choice of gate metal on conduction. Contact effects that are apparent in the current characteristics of thin Si3 N4 layers become dominated by bulk conduction mechanisms as the silicon nitride film increases in thickness. Optical interference effects in photoconduction are used to determine the origin of photocarriers.