EEPROM和SRAM瞬时剂量率效应比较

Comparison of Transient Radiation Effect Between EEPROM and SRAM

对一种256 kb EEPROM电路AT28C256和一种256 kb SRAM电路HM62256开展了"强光一号"瞬时剂量率效应实验,测量了存储器的闩锁效应、翻转效应等。HM62256的翻转阈值为9.0×106 Gy(Si)/s,闩锁阈值高于5.4×107 Gy(Si)/s。AT28C256的闩锁阈值为2×107 Gy(Si)/s,存储单元翻转阈值高于3.0×108 Gy(Si)/s。对于SRAM,其翻转阈值远低于闩锁阈值;而对于EEPROM,在瞬时辐照下,闩锁阈值远低于存储单元的翻转阈值。基于两种存储器的数据存储原理,分析了SRAM和EEPROM瞬时剂量率效应差异的原因。

AT28C256 is a kind of floating gate electrically erasable programmable read only memory and HM62256 is a kind of static random memory. Transient dose rate effects are studied for AT28C256 and HM62256 using Qiangguang-1 accelerator. The AT28C256 was found to be susceptible to dose rate latchup and average latchup level is 1.9 × 107 Gy（Si）/s Following 3.0 × 108 Gy（Si）/s, memory contents were retained and memory can erasure and program exactly in AT28C256. HM62256 was found to be susceptible to upset and average upset level is 0.9 × 107 Gy（Si）/s. Following 5.4 × 107 Gy（Si）/s, no latchup was happened in HM62256. Differences in memory structures and mechanism to store data are the causes for difference of transient radiation effects between EEPROMs and SRAMs.