SEU test techniques for 256 K static RAMs and comparisons of upsets by heavy ions and protons

Test procedures needed to observe the single-event phenomena for various 256 K CMOS/NMOS static RAMs are described. The tests were conducted with both protons and heavy ions, yielding correlated comparisons of results. Most of the single-event vulnerability data were obtained using EDI EDH8832C, IDT IDT71256, OMNI-WAVE OW62256, and RCA XCDM62256 32 K*8 static RAMs. Among the four device types only OW62256s were resistant to single-event latchup. Estimates of the single-event-upset (SEU) rate in space show that OW62256s are the least susceptible devices. The test and reduction methods took into consideration multiple upsets caused by a single ion, the effect of read/write access time, and scaling related to feature size. The scaling study was made possible by comparing the SEU test results of an additional four types of radiation-hardened IDT static RAMs.<
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