Invention Grant
- Patent Title: Soft erase operation for 3D non-volatile memory with selective inhibiting of passed bits
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Application No.: US14290224Application Date: 2014-05-29
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Publication No.: US08879333B2Publication Date: 2014-11-04
- Inventor: Xiying Costa , Haibo Li , Masaaki Higashitani , Man L Mui
- Applicant: SanDisk Technologies Inc.
- Applicant Address: US TX Plano
- Assignee: SanDisk Technologies Inc.
- Current Assignee: SanDisk Technologies Inc.
- Current Assignee Address: US TX Plano
- Agency: Vierra Magen Marcus LLP
- Main IPC: G11C11/34
- IPC: G11C11/34 ; G11C16/34 ; G11C16/14 ; G11C16/16 ; G11C11/56 ; G11C16/04

Abstract:
An erase operation for a 3D stacked memory device selectively inhibits subsets of memory cells which meet a verify condition as the erase operation progresses. As a result, the faster-erasing memory cells are less likely to be over-erased and degradation is reduced. Each subset of memory cells can be independently erased by controlling a select gate, drain (SGD) transistor line, a bit line or a word line, according to the type of subset. For a SGD line subset or a bit line subset, the SGD line or bit line, respectively, is set at a level which inhibits erase. For a word line subset, the word line voltage is floated to inhibit erase. An inhibit or uninhibit status can be maintained for each subset, and each type of subset can have a different maximum allowable number of fail bits.
Public/Granted literature
- US20140269081A1 SOFT ERASE OPERATION FOR 3D NON-VOLATILE MEMORY WITH SELECTIVE INHIBITING OF PASSED BITS Public/Granted day:2014-09-18
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