- Patent Title: Semiconductor memory device and memory system that performs a normal read operation or a special read operation including a tracking read followed by a shift read
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Application No.: US16238400Application Date: 2019-01-02
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Publication No.: US10720219B2Publication Date: 2020-07-21
- Inventor: Yoshikazu Harada
- Applicant: Toshiba Memory Corporation
- Applicant Address: JP Tokyo
- Assignee: Toshiba Memory Corporation
- Current Assignee: Toshiba Memory Corporation
- Current Assignee Address: JP Tokyo
- Agency: Kim & Stewart LLP
- Priority: com.zzzhc.datahub.patent.etl.us.BibliographicData$PriorityClaim@41a517ae
- Main IPC: G11C16/26
- IPC: G11C16/26 ; G11C11/56 ; G11C16/34 ; G11C16/04

Abstract:
A semiconductor memory device includes a memory cell array including a plurality of memory cells, a word line connected in common to gates of the memory cells, and a control circuit configured to execute a read operation on the memory cells by applying a first read voltage to the word line to determine for each of the memory cells whether or not the memory cell has a threshold voltage that is below the first read voltage and a second read voltage to the word line to determine for each of the memory cells whether or not the memory cell has a threshold voltage that is below the second read voltage. The control circuit determines the first read voltage by applying at least first to third voltages to the word line, and determines the second read voltage based on the first read voltage.
Public/Granted literature
- US20190139614A1 SEMICONDUCTOR MEMORY DEVICE AND MEMORY SYSTEM Public/Granted day:2019-05-09
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