Kabushiki Kaisha Toshiba

Kazuhisa Kanazawa

Hiroto Nakai

Hiroshi Iwahashi

Isao Sato

Hiroshi Nakamura

Toshio Yamamura

Makoto Iwai

Masaki Fujiu

Shigeru Kumagai

Koji Sakui

Takashi Mori

Hideo Kato

Masamichi Asano

Kaoru Tokushige

Yoshihisa Sugiura

A semiconductor memory device includes a memory cell array including a plurality of blocks each including a memory cell unit, and a selection transistor which selects the memory cell unit, and a row decoder including a first block selector and a second block selector each of which includes a plurality of transfer transistors which are formed to correspond to the plurality of blocks and arranged adjacent to each other in a word-line direction wherein the diffusion layers are formed to oppose each other in the first block selector and the second block selector, and a width between the diffusion layers of the first block selector and the second block selector adjacent to each other in the word-line direction is made larger than a width between the diffusion layers in each of the first block selector and the second block selector adjacent to each other in the word-line direction.

Semiconductor memory device

A memory cell array is divided into left and right cell arrays, each of which includes a plurality of blocks. Data erase is sequentially controlled by an erase control circuit on the basis of an erase command flag incorporated into a command register and an address incorporated into an address register. Batch erase is carried out with respect to selected blocks of the right and left cell arrays. After data erase, a verify operation is carried out with respect to the erased blocks by retrieving the erased blocks simultaneously with respect to the right and left cell arrays in parallel. Thus, the time required to retrieve the selected blocks for the verify operation after data erase is shortened, so that the time required to carry out the whole data erase is shortened.

Non-volatile semiconductor memory device and data erase controlling method for use therein

There is disclosed a semiconductor memory device comprising memory cells (M11 to Mmn) for storing binary data, and first reference cells (DM11 to DMm1) and second reference cells (DM12 to DMm2) corresponding to respective two storage states of the memory cell, to make comparisons between the storage state of the memory cell and the storage states of the both reference cells at first and second sense amplifiers (1, 2) to compare outputs from the both sense amplifiers at the third sense amplifier (3) to thereby detect storage data of the memory cell. Thus, there can be provided a high speed memory device which has a less number of memory cells and of a high integration structure, and which has a little possibility of an erroneous operation in reading.

Semiconductor memory device having redundant memory cells

In response to a plurality of address signal input from the outside in sequence, an erase information inputting section controls an erase information holding section corresponding to the batch erase block to be erased so as to hold an erase information data. By repeating this operation in sequence, the erase information data are stored in the erase information holding sections corresponding to the plural batch erase blocks to be erased. Successively, on the basis of the erase information data stored in the erase information holding sections, block erasing sections are activated to erase all the nonvolatile memory cells of each of the corresponding blocks where the erase information data are held. As a result, the erasure operation is achieved for all the batch erase blocks corresponding to the erase information holding sections in each of which the erase information data is held, so that a plurality of batch erase blocks can be erased simulataneously, thus reducing the erasure time, as compared with the prior art memory device.

Block erasable nonvolatile memory device

There is disclosed a semiconductor memory device comprising memory cells (M11 to Mnn) for storing binary data, and first reference cells (DM11 to Dm1) and second reference cells (DM12 to DMm2) corresponding to respective two storage states of the memory cell, to make comparisons between the storage state of the memory cell and the storage states of the both reference cells at first and second sense amplifiers (1, 2) to compare outputs from the both sense amplifiers at the third sense amplifier (3) to thereby detect storage data of the memory cell. Thus, there can be provided a high speed memory device which has a less number of memory cells and of a high integration structure, and which has a little possibility of an erroneous operation in reading.

In a semiconductor memory device, a first load circuit is coupled with the column lines, first dummy cells are connected to a dummy column line, a second load circuit is connected to the dummy column line, a second dummy cell is connected to the dummy column line, and a sense amplifier senses the data stored in the memory cell in accordance with a potential difference between the column line and the dummy column line. In semiconductor memory devices thus arranged, the second dummy cell is set in an on state normally. The connection of the second dummy cell with the dummy line changes a current flowing to the dummy line at the time of row line switching, thereby to hold back a rise of the reference potential at the time of the row line switching.

Growing community of inventors

Tokyo, Japan

Kazuhisa Kanazawa