CONTROL OF STABILITY AND CURRENT-VOLTAGE CHARACTERISTICS IN AMORPHOUSHYDROGENATED SILICON-NITRIDE THIN-FILM DIODES

Current transport and instability mechanisms in thin film diodes with nonstoichiometric silicon nitride (a-SiNx:H) semiconducting layers hav e been investigated, In common with amorphous silicon thin film transi stors the electrical characteristics of these diodes have been found t o drift during use. We found that the initial current-voltage characte ristics are related to the choice of interfacial treatments. This is e xplained by trapping of electrons at interface defect states and by tu nnelling of electrons into the conduction band via these states. We ha ve also found a relationship between the initial characteristics of th e diodes and the rate of drift due to electrical stressing. A threshol d exists below whose drift is independent of the current-voltage chara cteristics and above which there is a strong dependence. This dependen ce of drift on current-voltage characteristic is consistent with field enhanced defect creation in the a-SiNx:H layer. (C) 1997 American Ins titute of Physics.