公开(公告)号：US09786378B1

公开(公告)日：2017-10-10

申请号：US15367549

申请日：2016-12-02

Applicant: SanDisk Technologies LLC

Inventor： Zhengyi Zhang ,  Liang Pang ,  Caifu Zeng ,  Xuehong Yu ,  Yingda Dong

IPC: G11C11/34 ,  G11C16/04 ,  G11C16/16 ,  G11C16/34 ,  G11C16/10 ,  G11C16/26

CPC classification number: G11C16/16 ,  G11C16/0483 ,  G11C16/10 ,  G11C16/26 ,  G11C16/3445 ,  G11C16/3477

Abstract: A memory device and associated techniques provide a uniform erase depth for different blocks of memory cells which are at different distances from pass gates of a voltage source. In one approach, a voltage of a source side select gate transistor of a memory string is a decreasing function of the distance. In another approach, a magnitude or duration of an erase voltage at a source end of a memory string is an increasing function of the distance. Adjacent blocks can be arranged in subsets and treated as being at a common distance. In another approach, an additional erase pulse can be applied when the distance of the block exceeds a threshold. Other variables such as initial erase voltage and step size can also be adjusted as a function of distance.