非挥发性记忆体Read Disturb测试方法的研究

DDF是一种高容量的NAND Flash。以DDF产品为例,研究和讨论了它的Read Disturb测试方法。受测试时间的限制,只能选择局部的存储区间进行DDF的Read Disturb测试。这样局部区间的测试结果是否能够代表整个芯片的性能,设计了一套实验,对这个课题进行了研究和讨论。依据非挥发性记忆体产品的特性,主要以阈值电压的分布为参考来评价DDF芯片性能的一致性和性能恶化趋势的一致度。最后的实验结果证明了这种测试方法的正确性和合理性。这种分析方法也可以用于其他非挥发性记忆体产品的其他可靠性测试项目的评估。

Study on the Read Disturb Test for Non-Volatile Memory

DDF(double density flash memory)is a NAND flash with a high memory capacity.Taking DDF products for example,the test methodology of Read Disturb is studied.Under the restriction of limited test time,Read Disturb tests only on partial memory for DDF can be performed.Whether such partial test result can represent the performance of a full chip,to answer this question an experiment was designed based on the characteristics of NVM(non-volatile memory)products,to evaluate the conformance and the degradations of a DDF by the threshold voltage (Vt) distribution.From the test results,the feasibility and applicability of the proposed method are confirmed,which can also be applied to other reliability tests of NVM chips.