Title:
DATA DELETION DEVICE FOR NONVOLATILE SEMICONDUCTOR STORAGE DEVICE AND METHOD FOR MANUFACTURING NONVOLATILE SEMICONDUCTOR STORAGE DEVICE
Document Type and Number:
WIPO Patent Application WO/2018/150803
Kind Code:
A1
Abstract:
A data deletion device for a nonvolatile semiconductor storage device, which includes a plurality of cells (11), is provided with a control unit (2) for applying a voltage to the cells (11), wherein a first voltage is applied to the cells to write data thereto and a second voltage different from the first voltage is applied to the cells to delete data therefrom. The control unit (2) applies a constant value of the second voltage to the plurality of cells (11) during a period t1 a plurality of times to thereby place the plurality of cells (11) in a first deletion state. After placing the plurality of cells (11) in the first deletion state, the control unit (2) applies the second voltage to the plurality of cells (11) during a period t2 longer than the period t1, thereby placing the plurality of cells (11) in a second deletion state that is deeper than the first deletion state. When placing the plurality of cells (11) in the first deletion state, the control unit (2) varies the number of times the second voltage is applied during the period t1 according to the deletion conditions of the plurality of cells (11) for each cell (11) or a cell group (16) including a plurality of the cells (11).
Inventors:
YAKO KOICHI (JP)
NAKAYAMA YOSHIAKI (JP)
NAKAYAMA YOSHIAKI (JP)
Application Number:
PCT/JP2018/001431
Publication Date:
August 23, 2018
Filing Date:
January 18, 2018
Export Citation:
Assignee:
DENSO CORP (JP)
International Classes:
G11C16/34; G11C16/14
Foreign References:
| JP2002133882A | 2002-05-10 | |||
| JPH05234388A | 1993-09-10 |
Attorney, Agent or Firm:
YOU-I PATENT FIRM (JP)
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