Impact of Total Ionizing Dose on the Data Retention of a 65 nm SONOS-Based NOR Flash

In this paper, the impact of total ionizing dose on the data retention behavior of a silicon-oxide-nitride-oxide-silicon-based NOR flash nonvolatile memory is studied for the first time on a deep sub-micron 65-nm complementary metal-oxide semiconductor technology node. The fundamental nonvolatile single-level cell memory element utilizes uniform Fowler-Nordheim (F-N) tunneling for both program and erase operations. The data retention behavior is investigated on a 4-Mb NOR Flash-based memory array at space-level total ionizing dose (TID) exposures up to 500 krad. Excessive TID exposure reduces the program-erase window but improves the thermal emission coefficient and, hence, improves data retention.