Nonvolatile semiconductor memory device and its writing method
First Claim
1. A nonvolatile semiconductor memory device comprising:
- a memory cell array consisting of memory cells having a nonvolatile transistor capable of electrically writing, erasing and reading out information arranged in a matrix in a row direction and in a column direction;
a row selection circuit for selecting the memory cell in the row direction;
a column selection circuit for selecting the memory cell in the column direction; and
a control circuit for exercising a writing control on the memory cell selected by the row selection circuit and the column selection circuit by a command inputted from outside, wherein the control circuit is configured to be able to receive a first external write command and a second external write command, and performs a first threshold voltage control for writing the memory cell selected as a writing target to a first predetermined threshold voltage when receiving the first external write command, and a second threshold voltage control for writing the memory cell selected as a writing target to a second predetermined threshold voltage that is different from the first threshold voltage when receiving the second external write command.
1 Assignment
0 Petitions
Accused Products
Abstract
There is provided a nonvolatile semiconductor memory device and its writing method capable of controlling an increase in threshold voltage due to effects of adjacent memory cells and performing stable readout operations even if miniaturization of semiconductor memory devices proceeds further. The device comprises a memory cell array 411 having memory cells in a row and column directions, a row selection circuit 412, a column selection circuit 411, and a control circuit 405 for exercising writing control on a selected memory cell by an external command input. The control circuit performs a threshold voltage control for writing a memory cell selected as a writing target to a first predetermined threshold voltage when receiving a first external write command, and performs another threshold voltage control for writing the selected memory cell to a second predetermined threshold voltage different from the first threshold voltage when receiving a second external write command.
13 Citations
6 Claims
-
1. A nonvolatile semiconductor memory device comprising:
-
a memory cell array consisting of memory cells having a nonvolatile transistor capable of electrically writing, erasing and reading out information arranged in a matrix in a row direction and in a column direction;
a row selection circuit for selecting the memory cell in the row direction;
a column selection circuit for selecting the memory cell in the column direction; and
a control circuit for exercising a writing control on the memory cell selected by the row selection circuit and the column selection circuit by a command inputted from outside, whereinthe control circuit is configured to be able to receive a first external write command and a second external write command, and performs a first threshold voltage control for writing the memory cell selected as a writing target to a first predetermined threshold voltage when receiving the first external write command, and a second threshold voltage control for writing the memory cell selected as a writing target to a second predetermined threshold voltage that is different from the first threshold voltage when receiving the second external write command. - View Dependent Claims (2, 3, 4, 5, 6)
-
Specification