NAND Flash Program Operation： One Shot VS. Two Pass

讲解相关内容的文章很少，开始只搜索到本站一篇相关内容：浅谈NAND FLASH的两种编程方式
看完以后思路还不是很清晰，又发现了两篇FMS的主题演讲，在此简单总结分享。

1. Flash Memory Summit 2016， Thomas Parnell, IBM Research - Zurich.
2. Flash Memory Summit 2018， Vic Ye, YEESTOR.

One Shot TLC Program Operation

即Incremental Programming，很典型的ISPP Procedure。

更形象的Vth Distribution过程：
初始：

过程：

最后：

Two Pass TLC Program Operation

即对One Shot TLC Program的过程分解。

更形象的Vth Distribution过程：
Two Pass TLC Program Operation (4-8 Type)

Two Pass TLC Program Operation (2-8 Type)


Two Pass QLC Program Operation (8-16 Type)
参考2 Pass TLC Program Operation (4-8 Type)

1-Shot vs. 2-Pass Program

One Shot program operation: CT Cells 3D NAND
Two Pass program operation: FG Cells 3D NAND

Two Pass program operation 比One Shot program operation更复杂更慢。但是FG Cells 3D NAND为啥选择使用Two Pass program operation？这是因为Two Pass program在FG Cells 3D NAND上的Vth分布相对于One Shot program来说更不易产生Fail bit。