Techniques are provided for improving the accuracy of read operations of memory cells, where the threshold voltage of the memory cells can shift depending on the coupled up state of the word lines. In one approach, for a read operation, a representative word line voltage in a block is detected and a corresponding set of read voltages is selected. In another approach, a pre-read voltage pulse is applied to a selected word line in response to a read command, just prior to reading the selected cells. In another approach, a voltage pulse is periodically applied to each word line in a block to provide the word lines in a coupled up state. In another approach, a soft erase is performed after a read operation to prevent coupling up of the word lines.

A two-sided, staged programming operation is applied to a memory having first and second stacks of memory cells C1(i) and C2(i), i being the physical level of a cell. The staged programming operation includes applying a preliminary program stage S1, an intermediate program stage S2, and a final program stage S3 to memory cells in the first and second stacks. In a programming order the final program stage S3 is applied to memory cells in the first and second stacks at each level (i) for which the intermediate program stage S2 has already been applied to the memory cells in any neighboring levels (levels i+1 and i1). The intermediate program stage S2 is applied only to memory cells for which the preliminary program stage S1 has already been applied to the cells in any neighboring levels (levels i+1 and i1).

Memory arrays and reading, programming and erasing methods of the memory arrays are provided. An exemplary memory array includes a plurality of memory columns. Each memory column has a plurality of flash memory cells. The memory columns are divided into at least two blocks. At least one source pull down column is disposed between the two adjacent blocks. Each source pull down column has a plurality of flash memory cells. A source of each flash memory cell in the source pull down column is coupled to sources of the flash memory cells of the plurality memory columns in a same row as the flash memory cell in the source pull down column to pull down a source of a selected flash memory cell to 0 V.

A data storage device includes a semiconductor structure including a first conductive-type region having a first-type conductivity, a second conductive-type region spaced apart from the first conductive-type region and having a second-type conductivity opposite to the first-type conductivity, and a semiconductor region between the first conductive-type region and the second conductive-type region and including a neighboring portion adjacent to the second conductive-type region; a mode select transistor including a gate electrode aligned with the neighboring portion and an insulation layer between the gate electrode and the neighboring portion; a plurality of memory cell transistors including a plurality of control gate electrodes aligned with the semiconductor region, and a data storage layer interposed between the plurality of control gate electrodes and the semiconductor region; a first wire electrically connected to the first conductive-type region; and a second wire including an ambipolar contact having a first contact between the second wire and the second conductive-type region, and a second contact between the second wire and the neighboring portion.

A nonvolatile semiconductor memory device includes a control circuit configured to control a soft program operation of setting nonvolatile memory cells to a first threshold voltage distribution state of the nonvolatile memory cells. When a characteristic of the nonvolatile memory cells is in a first state, the control circuit executes the soft program operation by applying a first voltage for setting the nonvolatile memory cells to the first threshold voltage distribution state to first word lines, and applying a second voltage higher than the first voltage to a second word line. When the characteristic of the nonvolatile memory cells is in a second state, the control circuit executes the soft program operation by applying a third voltage equal to or lower than the first voltage to the first word lines and applying a fourth voltage lower than the second voltage to the second word line.

A data storage device includes a semiconductor structure including a first conductive-type region having a first-type conductivity, a second conductive-type region spaced apart from the first conductive-type region and having a second-type conductivity opposite to the first-type conductivity, and a semiconductor region between the first conductive-type region and the second conductive-type region and including a neighbouring portion adjacent to the second conductive-type region; a mode select transistor including a gate electrode aligned with the neighbouring portion and an insulation layer between the gate electrode and the neighbouring portion; a plurality of memory cell transistors including a plurality of control gate electrodes aligned with the semiconductor region, and a data storage layer interposed between the plurality of control gate electrodes and the semiconductor region; a first wire electrically connected to the first conductive-type region; and a second wire including an ambipolar contact having a first contact between the second wire and the second conductive-type region, and a second contact between the second wire and the neighbouring portion.

A nonvolatile semiconductor memory device includes a control circuit configured to control a soft program operation of setting nonvolatile memory cells to a first threshold voltage distribution state of the nonvolatile memory cells. When a characteristic of the nonvolatile memory cells is in a first state, the control circuit executes the soft program operation by applying a first voltage for setting the nonvolatile memory cells to the first threshold voltage distribution state to first word lines, and applying a second voltage higher than the first voltage to a second word line. When the characteristic of the nonvolatile memory cells is in a second state, the control circuit executes the soft program operation by applying a third voltage equal to or lower than the first voltage to the first word lines and applying a fourth voltage lower than the second voltage to the second word line.

A nonvolatile semiconductor memory device includes a control circuit configured to control a soft program operation of setting nonvolatile memory cells to a first threshold voltage distribution state of the nonvolatile memory cells. When a characteristic of the nonvolatile memory cells is in a first state, the control circuit executes the soft program operation by applying a first voltage for setting the nonvolatile memory cells to the first threshold voltage distribution state to first word lines, and applying a second voltage higher than the first voltage to a second word line. When the characteristic of the nonvolatile memory cells is in a second state, the control circuit executes the soft program operation by applying a third voltage equal to or lower than the first voltage to the first word lines and applying a fourth voltage lower than the second voltage to the second word line.

The present technology relates to a memory device and a method of operating the same. The memory device includes a plurality of memory blocks each including a plurality of memory cells, peripheral circuits configured to perform a background operation and an overwrite operation on a selected memory block among the plurality of memory blocks, and control logic configured to control the peripheral circuits to perform the background operation and the overwrite operation, and the control logic controls the peripheral circuits to perform the overwrite operation including increasing a threshold voltage of the plurality of memory cells of the selected memory block to at least a predetermined threshold voltage value based on the quantity of valid data stored in the selected memory block.