Improvement in retention reliability of SONOS nonvolatile memory devices by two-step high temperature deuterium anneals

The deterioration of the Si-SiO/sub 2/ interface is associated with the degradation of long term retention in polysilicon-oxide-nitride-oxide-silicon (SONOS) nonvolatile semiconductor memory (NVSM) devices. Two-step high temperature deuterium anneals, applied in SONOS device fabrication for the first time, improve the endurance characteristics and retention reliability over traditional hydrogen anneals. Electrical characterization shows deuterium-annealed SONOS devices have nearly one order of magnitude longer projected retention time than hydrogen-annealed devices after 10/sup 7/ erase/write cycles at 85/spl deg/C to provide an extrapolated 0.5 V detection window. In this paper, we introduce the annealing process along with experiment results.