Design considerations in scaled SONOS nonvolatile memory devices

Scaling the programming voltage, while still maintaining 10-year data retention time, has always been a big challenge for polysilicon-oxide-nitride-oxide-silicon (SONOS) researchers. We describe progress in the design and scaling of SONGS nonvolatile memory devices. We have realized -9 + 10 V (1 ms) programmable SONGS devices ensuring 10-year retention time after 10: erase/write cycles at 85 degreesC. Deuterium anneals, applied in SONGS device fabrication for the first time. improves the endurance characteristics when compared with traditional hydrogen or forming gas anneals. We introduce scaling considerations and process optimization along with experiments and SONGS device characterization. A field programmable gate array-based measurement system is described for the dynamic characterization of SONGS nonvolatile memory devices. (C) 2001 Elsevier Science Ltd. All rights reserved.