NAND闪存写入（编程）干扰研究

发布时间：2018-04-09 07:39

本文选题：NAND闪存　切入点：NOR　出处：《苏州大学》2013年硕士论文

【摘要】：闪存（Flash Memory）是一种长寿命的非易失性（在断电情况下仍能保持所存储的数据信息）的存储器。由于其断电后仍能保存数据，闪存通常被用来保存设置信息，如在电脑的BIOS（基本输入输出程序）、PDA（个人数字助理）、数码相机中保存资料等。闪存分为NOR型与NAND型，目前NAND闪存是一种比硬盘驱动器更好的存储方案，这在不超过8GB的低容量应用中表现的犹为明显。随着人们持续追求功耗更低、重量更轻和性能更佳的产品，NAND闪存正被证明极具吸引力。 NAND闪存作为一种比较实用的固态硬盘存储介质，有自己的一些物理特性，NAND闪存的电荷非常不稳定，在写入（编程）时很容易对邻近的单元造成干扰，，干扰后会让附近单元的电荷脱离实际的逻辑数值，造成位（bit）出错。由于阈值电压接近的关系，MLC相对SLC来说更容易受到干扰，如何改善写入（编程）干扰是本文研究的主要方向。写入（编程）干扰指的是，某个页(page)在写入（编程）时，邻近位（bit）的电压也被升高了，造成位（bit）出错。为了保证写入数据的完整性,研究如何减少写入（编程）干扰造成的数据出错显得尤为重要，除了芯片级测试参数的修改与写入（编程）的方法可以改善写入（编程）干扰，在系统级测试中，通过ECC算法也可以纠正这些位（bit）的错误。随着NAND闪存工艺的不断提升，同样大小的晶片上被封装入更多的单元，造成干扰越来越厉害，所以需要更强大的ECC来纠正位（bit）。本文重点研究了NAND闪存写入（编程）干扰的原理，由浅入深的介绍了NAND闪存写入（编程）干扰的特性与种类以及各自的改善方法，并结合NAND闪存实际测试过程中遇到的写入（编程）干扰问题，对NAND闪存写入（编程）干扰提出了合理的改善意见与建议。
[Abstract]:Flash memory (Flash memory) is a kind of memory with long life and non-volatile (the stored data information can be maintained in the case of power failure).Because it can save data after power off, flash memory is usually used to save setup information, such as PDAs (personal digital assistant, digital camera) and so on.Flash memory is divided into NOR type and NAND type. At present, NAND flash memory is a better storage scheme than hard disk drive.As people continue to pursue lower power, lighter and better performance products, NAND flash memory is proving to be extremely attractive.As a practical solid state hard disk storage medium, NAND flash memory has its own physical characteristics. The charge of NAND flash memory is very unstable, and it is easy to interfere with adjacent units when writing (programming).The interference causes the charge of the nearby cell to deviate from the actual logical value, resulting in bit error.Because of the close threshold voltage, MLC is more susceptible to interference than SLC. How to improve write (programming) interference is the main research direction of this paper.Write (programming) interference means that when a page pageis written, the voltage of the adjacent bit is also raised, causing bit error.In order to ensure the integrity of writing data, it is very important to study how to reduce the data error caused by write (programming) interference, except that the modification of test parameters at chip level and the method of writing (programming) can improve write (programming) interference.In system-level testing, these bit-bit errors can also be corrected by the ECC algorithm.As the NAND flash memory process continues to improve, the same size of the chip is encapsulated in more units, causing more and more interference, so a stronger ECC is needed to correct the bitbit.This paper focuses on the principle of NAND flash write (programming) interference, introduces the characteristics and types of NAND flash memory write (programming) interference and their respective improvement methods.Combining with the problem of write (programming) interference encountered in the process of NAND flash memory testing, the paper puts forward some reasonable suggestions for improving the write (programming) interference of NAND flash memory.
【学位授予单位】：苏州大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TP333

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