Kioxia Corporation

Toshiba Memory Corporation

Tomoki Nakagawa

Koji Kato

Toshifumi Hashimoto

Koji Hosono

Mai Shimizu

Shuhei Oketa

A semiconductor memory device includes a memory string, a voltage supply circuit, a plurality of control signal lines, a row decoder, and a control circuit. The voltage supply circuit is configured to generate a plurality of operation voltages to operate the semiconductor memory device. The operation voltages include a negative voltage. The plurality of control signal lines is connected between the voltage supply circuit and the memory string. The row decoder includes a plurality of transistors provided in the plurality of control signal lines, respectively. The control circuit is configured to control the transistors of the row decoder, and cause the negative voltage to be supplied to the row decoder during a certain period of time in which a voltage of one of the control signal lines drops to a negative level.

Semiconductor memory device

A semiconductor memory device includes a plurality of memory cells, a word line connected to gates of the memory cells, a bit line electrically connected to one ends of the memory cells through a plurality of select gate transistors, respectively, the select gate transistors including two outer select gate transistors and one or more inner select gate transistors between the two outer select gate transistors, two outer select gate lines connected to gates of the two outer select gate transistors, respectively, one or more inner select gate lines connected to gates of the one or more inner select gate transistors, respectively, and a voltage generation circuit configured to independently control supply of voltages to the outer select gate lines and the inner select gate lines during an operation to read data stored in the memory cells.

A semiconductor memory device includes memory cell transistors, a word line connected to the plurality of memory cell transistors, bit lines that are respectively connected to the memory cell transistors, and a control circuit. The control circuit carries out a write operation on the memory cell transistors connected to the word line by performing, in sequence, a first loop of operations, including a first program operation followed by at least one verification operation, that are carried out until all memory cell transistors targeted by the first program operation have passed the at least one verification operation, a second loop of operations, including a second program operation and no verification operation, that are carried out for a fixed number of loops and a third loop of operations, including a third program operation and no verification operation, that are carried out for a fixed number of loops.

Growing community of inventors

Yokohama Kanagawa, Japan

Tomoki Nakagawa