Heavy ion test results on memories

A synthesis is presented of heavy ion single event upset and latch-up sensitivity test results on 12 memory types from various technologies. Test data for CMOS and SOI SRAMs, FG/EEPROMs and SNOS/EEPROMs are presented. After a presentation of the test conditions, the interpretation of the results for high density technologies are discussed. The test results are then summarized and discussed in detail. The data collected for high density SRAMs revealed a deviation from the effective LET cos theta law. This phenomenon may be correlated to the shape of the sensitive area. Some products exhibited a strong sensitivity asymmetry (0 to 1 or 1 to 0 transitions). This effect has been correlated to the basic cell design. In addition, an ion species dependence has been noticed for one type. A normalized plot showing a common behaviour of all the devices tested is presented. With respect to these phenomena, some guidelines are suggested to achieve a full characterization of the devices.<
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