A non-volatile memory device includes a plurality of memory cells arranged in a matrix, a plurality of word lines extended in a row direction, and a plurality of bit lines extended in a column direction. Each of the memory cells is coupled to one of the word lines and one of the bit lines. The memory device further includes a word-line control circuit coupled to and configured to control the word lines, a first bit-line control circuit configured to control the bit lines and sense the memory cells in a digital mode, and a second bit-line control circuit configured to bias the bit lines and sense the memory cells in an analog mode. The first bit-line control circuit is coupled to a first end of each of the bit lines. The second bit-line control circuit is coupled to a second end of each of the bit lines.

A semiconductor device includes a substrate, a plurality of word line structures disposed over the substrate to be spaced apart from each other in a first direction perpendicular to a surface of the substrate. Each of the plurality of word line structures extends in a second direction parallel to the surface of the substrate. In addition, the semiconductor device includes a switching layer disposed over the substrate to contact side surfaces of the plurality of word line structures, and bit line structures disposed over the substrate to extend in the first direction and to contact a surface of the switching layer. The switching layer is configured to perform a threshold switching operation, and has a variable programmable threshold voltage.

Systems, methods and apparatus to program a memory cell to have a threshold voltage to a level representative of one value among more than two predetermined values. A first voltage pulse is driven across the memory cell to cause a predetermined current to go through the memory cell. The first voltage pulse is sufficient to program the memory cell to a level representative of a first value. To program the memory cell to a level representative of a second value, a second voltage pulse, different from the first voltage pulse, is driven across the memory cell within a time period of residual poling in the memory cell caused by the first voltage pulse.

Methods and systems include memory devices with a memory array comprising a plurality of memory cells. The memory devices include a control circuit operatively coupled to the memory array and configured to receive a read request for data and to apply a first voltage at a first time duration to the memory array based on the read request. The control circuit is additionally configured to count a number of the plurality of memory cells that have switched to an active read state based on the first voltage and to derive a second time duration. The control circuit is further configured to apply a second voltage at the second duration to the memory array. The control circuit is also configured to return the data based at least on bits stored in a first and a second set of the plurality of memory cells.

A read reference current generator includes a temperature coefficient (TC) controller configured to adjust a temperature coefficient in response to a first control signal and generate a read reference current having an adjusted temperature coefficient, a plurality of replica circuits configured to receive the read reference current and adjust an absolute value of the read reference current with different scale factors to generate a plurality of branch currents, and a plurality of switches configured to control connection of the TC controller and the plurality of replica circuits in response to a second control signal, wherein an equivalent resistance value of each of the plurality of replica circuits corresponds to a multiple of an equivalent resistance value of a data read path, and the data read path includes a selected memory cell and a clamping circuit clamping a voltage level of a selected bit line to a determined value.

Techniques for burst memory write operations are disclosed. In the illustrative embodiment, a memory die is limited in how quickly it can perform memory write operations that it receives from a microcontroller due to thermal constraints. The memory die can mitigate the need for the microcontroller to perform a costly rank switch to send an operation to another die by buffering memory write operations. The microcontroller can then send several consecutive memory write operations to a first memory die before switching to a second memory die. The first memory die can then perform the memory write operations while the microcontroller has moved on to other memory operations.

A read technique for both SLC (single level cell) and MLC (multi-level cell) cross-point memory can mitigate drift-related errors with minimal or no drift tracking. In one example, a read at a higher magnitude voltage is applied first, which causes the drift for cells in a lower threshold voltage state to be reset. In one example, the read at the first voltage can be a full float read to minimize disturb. A second read can then be performed at a lower voltage without the need to adjust the read voltage due to drift.

An operation method for a memory device is provided. The memory device includes a two-terminal selector and a resistance variable storage element coupled to the two-terminal selector. The method includes providing a voltage pulse to the memory device. A voltage applied across the two-terminal selector during a falling part of the voltage pulse falls below a holding voltage of the two-terminal selector. A voltage falling rate of the falling part at which the voltage applied across the two-terminal selector reaches the holding voltage is raised for reducing threshold voltage drift of the two-terminal selector.

Provided herein may be a resistive memory device and a method of operating the resistive memory device. The resistive memory device may include strings coupled between one or more source lines and one or more bit lines, each string including a set of one or more resistive memory cells, one or more word lines respectively coupled to the set of one or more resistive memory cells; and a voltage generator configured to control a level of a turn-on voltage to be applied to one or more unselected word lines among the one or more word lines depending on a program target state of a subset of resistive memory cells including one or more resistive memory cells selected from among the set of one or more resistive memory cells.

Technologies relating to CMOS image sensors with integrated Resistive Random-Access Memory (RRAMs) units that provide energy efficient analog storage, ultra-high speed analog storage, and in-memory computing functions are disclosed. An example CMOS image sensor with integrated RRAM crossbar array circuit includes a CMOS image sensor having multiple pixels configured to receive image signals; a column decoder configured to select the pixels in columns to read out; a row decoder configured to select the pixels in rows to read out; an amplifier configured to amplify first signals received from the CMOS image sensor; a multiplexer configured to sequentially or serially read out second signals received from the amplifier; and a first RRAM crossbar array circuit configured to store third signals received from the multiplexer.