Radiation-Induced Modifications of the Electrical Characteristics of Nanocrystal Memory Cells and Arrays

Abstract

Proton irradiation on Nanocrystals Memories\ud produces peculiar radiation effects on the electrical\ud characteristics of these devices, owing to their thin tunnel oxide\ud and to the presence of nanocrystals replacing the Flash memory\ud conventional floating gate. In this work we show that the data\ud retention capability is compromised only after high fluences and\ud that irradiated devices do not show accelerated degradation\ud during subsequent electrical stresses. The presence of\ud nanocrystals instead of a floating gate reduces also the quantity\ud of charge lost during irradiation, indicating these devices as\ud possible candidates for space and avionic environment

Radiation Tolerance of Nanocrystal-Based Flash Memory Arrays Against Heavy Ion Irradiation

“…The first work on prototype NCM intended to evaluate different cell designs and processes [19] presented results on nanocrystal memories, favorably comparing with those on currently available commercial flash technology, and indicating a promising future for NCM even for space and military applications. In [20] and [21] we showed promising results regarding NCM in terms of both single event and total irradiated dose effects, highlighting that NCM's can tolerate radiation doses as high as several Mrad's.…”

“…In the last years it has been demonstrated that NCMs have a very good potential in retaining the electric charge within the nanocrystal layer after irradiation [19]- [21]. However, most of these results have been obtained by studying the "average" characteristics of CAST (Cell Array Stress Test) structures, featuring 256 kbit cells with parallel connection.…”