In this article, we studied the total ionization dose (TID) effects on the multilevel-cell (MLC) 3-D NAND flash memory using Co-60 gamma radiation. We found a significant page-to-page bit error variation within a physical memory block of the irradiated memory chip. Our analysis showed that the origin of the bit error variation is the unique vertical layer-dependent TID response of the 3-D NAND. We found that the memory pages located at the upper and lower layers of the 3-D stack show higher fails compared to the middle-layer pages of a given memory block. We confirmed our findings by comparing radiation response of four different chips of the same specification. In addition, we compared the TID response of the MLC 3-D NAND with that of the 2-D NAND chip, which showed less page-to-page variation in bit error within a given memory block. We discuss the possible application of our findings for the radiation-tolerant smart memory controller design.

中文翻译：

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电离辐射下 3-D NAND 闪存中的层相关误码变化

在本文中，我们研究了使用 Co-60 伽马辐射对多级单元 (MLC) 3-D NAND 闪存的总电离剂量 (TID) 影响。我们在受辐射的存储芯片的物理存储块中发现了显着的页到页位错误变化。我们的分析表明，误码变化的根源是 3-D NAND 独特的垂直层相关 TID 响应。我们发现，与给定内存块的中间层页面相比，位于 3-D 堆栈上层和下层的内存页面显示出更高的失败率。我们通过比较相同规格的四种不同芯片的辐射响应来证实我们的发现。此外，我们将 MLC 3-D NAND 的 TID 响应与 2-D NAND 芯片的 TID 响应进行了比较，后者显示给定存储块内的页间位错误变化较小。