Kabushiki Kaisha Toshiba

Kunihiro Yamada

Yoshiaki Fukuzumi

Hideaki Aochi

Masaru Kito

Yoshihisa Iwata

Ryouhei Kirisawa

Tomoko Fujiwara

Yoshimasa Mikajiri

Kiyotaro Itagaki

Naoyuki Shigyo

Hideto Horii

Kaori Kawasaki

Michiru Hogyoku

According to one embodiment, a semiconductor memory device includes: semiconductor member; electrode member; charge accumulation member; a memory unit; and a control unit. Memory cell is formed at each crossing portion of the semiconductor member and the electrode member. The memory unit retains information indicating that the memory cell belongs to first group or second group. The control unit performs first step and second step, when reducing the charge accumulated in the charge accumulation member. In the first step, first voltage is applied both between the semiconductor member and the electrode member of the first group and between the semiconductor member and the electrode member of the second group. In the second step, second voltage is applied between the semiconductor member and the electrode member constituting the memory cell belonging to the second group.

Semiconductor memory device and method for driving the same

According to one embodiment, a method of operating a semiconductor memory device is disclosed. The method can include storing read-only data in at least one selected from a memory cell of an uppermost layer and a memory cell of a lowermost layer of a plurality of memory cells connected in series via a channel body. The channel body extends upward from a substrate to intersect a plurality of electrode layers stacked on the substrate. The method can include prohibiting a data erase operation of the read-only memory cell having the read-only data stored in the read-only memory cell.

Method of operating semiconductor memory device

A control circuit is configured to set a drain-side select transistor and a source-side select transistor connected to a selected memory string to non-conductive states. The control circuit is configured to apply a first voltage to a non-selected word line connected to a gate of a non-selected memory cell in the selected memory string. The control circuit is configured to apply a second voltage to a selected word line connected to a gate of a selected memory cell in the selected memory string. The second voltage is smaller than the first voltage in an erasing operation.

Nonvolatile semiconductor memory device and method for erasing data thereof

A non-volatile semiconductor memory device according to one aspect of an embodiment of the present invention includes: a semiconductor substrate; an element region; a plurality of memory cell transistors which each include a control gate electrode; and programming means for programming data to a programming target memory cell transistor by applying a programming voltage to the programming target memory cell transistor. Moreover, the programming means applies a programming voltage incremented stepwise from an initial programming voltage, to the programming target memory cell transistor while applying a constant initial intermediate voltage to memory cell transistors adjacent to the programming target memory cell transistor. Thereafter, the programming means applies an intermediate voltage incremented stepwise from the initial intermediate voltage, to one of the respective memory cells adjacent to the programming target memory cell transistor, while applying a constant final programming voltage to the programming target memory cell transistor.

Non-volatile semiconductor memory device and a programming method thereof

Growing community of inventors

Suzuka, Japan

Kunihiro Yamada