Radiation Tolerance of NROM Embedded Products

Radiation tolerance of NROM memories is demonstrated at the level of industrial 4 Mbit memory embedded modules, specifically not designed for operation in radiation harsh environments. The memory fabricated in 0.18 um technology remains fully functional after total ionization doses exceeding 100 krad. The tests were performed by irradiating with γ-rays ( ⁶⁰Co source) and 10 MeV ¹¹B ions in active (during programming/erase and read-out) and passive (no bias) modes. Comprehensive statistics were obtained by using large memory arrays and comparison of the data with the parameters of irradiated single cells allowed deep understanding of the physical phenomena in the irradiated NROM devices for both moderate (<;1 Mrad) and large (> 1 Mrad) TID. The obtained data is currently employed in the design of the new generation of NROM memories, having improved radiation tolerance.