- 专利标题: Equalizing erase depth in different blocks of memory cells
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申请号: US15367549申请日: 2016-12-02
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公开(公告)号: US09786378B1公开(公告)日: 2017-10-10
- 发明人: Zhengyi Zhang , Liang Pang , Caifu Zeng , Xuehong Yu , Yingda Dong
- 申请人: SanDisk Technologies LLC
- 申请人地址: US TX Plano
- 专利权人: SanDisk Technologies LLC
- 当前专利权人: SanDisk Technologies LLC
- 当前专利权人地址: US TX Plano
- 代理机构: Vierra Magen Marcus LLP
- 主分类号: G11C11/34
- IPC分类号: G11C11/34 ; G11C16/04 ; G11C16/16 ; G11C16/34 ; G11C16/10 ; G11C16/26
摘要:
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.
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