According to an embodiment, a control circuitry performing: a first operation of reading data out of a memory cell with a first voltage applied to a word line while changing the first voltage by a first shift amount within a first range, and a second operation of reading data out of the memory cell with a second voltage applied to the word line while changing the second voltage by a second shift amount within a second range, wherein the second shift amount is smaller than the first shift amount, and wherein the control circuitry performs the second operation to apply the second voltage to the word line subsequently to application of the first voltage to the word line in the first operation.

Numerous embodiments are disclosed for compensating for differences in the slope of the current-voltage characteristic curve among reference transistors, reference memory cells, and flash memory cells during a read operation in an analog neural memory in a deep learning artificial neural network. The embodiments are able to compensate for slope differences during both sub-threshold and linear operation of reference transistors.

According to one embodiment, a memory system includes a semiconductor memory and a controller. The semiconductor memory includes first blocks including a memory cell capable of storing data of one bit, a second block including a memory cell capable of storing data of two or more bits. The semiconductor memory stores first data in a first latch circuit, and second data in a second latch circuit, and writes the first data into one of the first blocks in page units, and the second data into one of the first blocks in page units. The semiconductor memory writes data of at least two pages into the second block, using the first data stored in the first latch circuit and the second data stored in the second latch circuit.

A memory device includes; a memory area including a first memory area including first memory cells storing N-bit data and a second memory area including second memory cells storing M-bit data, where ‘M’ and ‘N’ are natural numbers and M is greater than N, and a controller configured to read data stored in the first memory area using a first read operation, read data stored in the second memory area using a second read operation different from the first read operation, and selectively store data in one of the first memory area and the second memory area based on a frequency of use (FOU) of the data.

Presented herein is a memory device and a method of operating the memory device. The memory device may include a memory cell, and a page buffer coupled to the memory cell via a bit line and configured to perform a read operation on the memory cell. The page buffer may include a storage unit configured to control a bit line precharge operation during the read operation and to store a result value of a first sensing operation. After the bit line precharge operation, a value stored in the storage unit is inverted before the storage unit stores the result value of the first sensing operation.

A semiconductor memory device includes a memory cell, a word line connected to the memory cell, a source line connected to the memory cell, a bit line connected to the memory cell, and a control circuit configured to perform a read operation on the memory cell. During the read operation, the control circuit applies to the word line a first voltage, a second voltage greater than the first voltage after applying the first voltage, and a third voltage greater than the first voltage and smaller than the second voltage after applying the second voltage, and applies to the source line a fourth voltage according to a timing at which the second voltage is applied to the word line, a fifth voltage smaller than the fourth voltage after applying the fourth voltage, and a sixth voltage greater than the fifth voltage after applying the fifth voltage.

A nonvolatile memory device including: a memory cell array, the memory cell array including a plurality of cell strings, at least one of the cell strings including a plurality of memory cells stacked in a direction perpendicular to a surface of a substrate, at least one of the memory cells is a multi-level cell storing at least three bits; and a control logic circuit configured to control a page buffer to read a fast read page of the memory cells with one read voltage and at least two normal read pages of the memory cells with the same number of read voltages.

A material layer stack, a non-volatile memory device comprising the stack, and arrays thereof are described. The material layer stack comprises first and second magnetic tunnel junctions and a first top electrode formed on a top face of the stack. A shoulder is formed on a lateral face of the stack and divides the stack into a lower portion and an upper portion, wherein a tunnel barrier of the first magnetic tunnel junction is comprised by the lower stack portion and a tunnel barrier of the second magnetic tunnel junction by the upper stack portion. A second top electrode is formed on the shoulder. Each magnetic tunnel junction is adapted to store a bit as a reconfigurable magnetoresistance of its magnetic electrodes. Preferably, a bottom face of the stack is connected to a conductor supporting current induced magnetic polarization switching for the first magnetic tunnel junction by spin-orbit torque; magnetic polarization switching for the second magnetic tunnel junction is preferably achieved by spin-transfer torque.

According to one embodiment, a memory system includes: a semiconductor memory including a memory cell array, the memory cell array including a memory cell, and a controller configured to issue a first read command sequence after a lapse of a first time period from access to the semiconductor memory, and issue a second read command sequence after a lapse of a second time period from access to the semiconductor memory. When the controller issues the first read command sequence, the semiconductor memory applies a first voltage and a second voltage to the memory cell. When the controller issues the second read command sequence, the semiconductor memory applies a third voltage and a fourth voltage to the memory cell.

A semiconductor memory device includes a memory cell, a word line connected to the memory cell, a source line connected to the memory cell, a bit line connected to the memory cell, and a control circuit configured to perform a read operation on the memory cell. During the read operation, the control circuit applies to the word line a first voltage, a second voltage greater than the first voltage after applying the first voltage, and a third voltage greater than the first voltage and smaller than the second voltage after applying the second voltage, and applies to the source line a fourth voltage according to a timing at which the second voltage is applied to the word line, a fifth voltage smaller than the fourth voltage after applying the fourth voltage, and a sixth voltage greater than the fifth voltage after applying the fifth voltage.