Kabushiki Kaisha Toshiba

Hitoshi Ohta

Tomohito Kawano

Akira Umezawa

Yuuichi Tatsumi

Hidenobu Minagawa

Noriaki Suzuki

Kazuhiko Satou

A nonvolatile semiconductor storage device includes a memory cell array including a plurality of memory cells arranged at intersection positions of word lines and bit lines in a matrix form, and a row decoder including a row sub-decoder to which a lower address for selecting a word line is input, wherein one unit of the row sub-decoder for selecting one word line is constituted of a first transistor of a first conduction type, and a second transistor of a second conduction type, and a gate electrode of each of the first and second transistors is arranged in a direction in which the bit lines are arranged.

Nonvolatile semiconductor storage device and method of testing the same

A non-volatile semiconductor memory includes a memory cell array. The memory cell array includes a plurality of banks, redundant blocks, and special blocks storing management data. Each bank includes a plurality of normal blocks, which include a plurality of electrically rewritable memory cells, the normal block being a minimum unit which is independently erased, and the redundant block configured to replace the normal block and being incapable of replacing the special block. A defective block automatic replacement sequence control circuit controls the replacement operation of the defective block FBLK with the redundant block RBLK in a defective block automatic replacement sequence.

Non-volatile semiconductor memory and method for replacing defective blocks thereof

That surface portion of a semiconductor substrate which is adjacent to a buried source region formed in the substrate is covered with an offset side wall to suppress expansion of a channel beneath the offset side wall. In addition, buried source regions in the form of offset side walls are formed on the two sides of a drain region having one non-offset side wall to prevent a write or read error in unselected memory cell transistors on both sides of a selected memory transistor either in a data write or in a data read.

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Yokohama, Japan

Hitoshi Ohta