Methods, systems, and devices for accessing a multi-level memory cell are described. The memory device may perform a read operation that includes pre-read portion and a read portion to access the multi-level memory cell. During the pre-read portion, the memory device may apply a plurality of voltages to a plurality of memory cells to identify a likely distribution of memory cells storing a first logic state. During the read portion, the memory device may apply a first read voltage to a memory cell based on performing the pre-read portion. The memory device may apply a second read voltage to the memory cell during the read portion that is based on the first read voltage. The memory device may determine the logic state stored by the memory cell based on applying the first read voltage and the second read voltage.

Systems, methods, and apparatus related to dynamically determining read voltages used in memory devices. In one approach, a memory device has a memory array including memory cells. One or more resistors are formed as part of the memory array. A memory controller increments a counter as write operations are performed on the memory cells. When the counter reaches a limit, a write operation is performed on the resistors. The write operation applies voltages to the resistors similarly as applied to the memory cells over time during normal operation. When performing a read operation, a current is applied to one or more of the resistors to determine a boost voltage. When reading the memory cells, a read voltage is adjusted based on the boost voltage. The memory cells are read using the adjusted read voltage.

A vertical resistive memory array is presented. The array includes a pillar electrode and a switching liner around the side perimeter of the pillar electrode. The array includes two or more vertically stacked single cell (SC) electrodes connected to a first side of the switching liner. The juxtaposition of the switching liner, the pillar electrode, and each SC electrode forms respective resistance switching cells (e.g., OxRRAM cell). A vertical group or bank of these cells may be connected in parallel and each share the same pillar electrode. The cells in the vertical cell bank may written to or read from as a group to limit the effects of inconsistent CF formation of any one or more individual cells within the group.

A resistance change device includes a first resistance change layer that occludes and discharges ions of at least one type, and resistance of the first resistance change layer, changes in accordance with an amount of the ions in such a manner that the resistance decreases when the ions are discharged and the resistance increases when the ions are occluded; a second resistance change layer that occludes and discharges the ions, and resistance of the second resistance change layer changes in accordance with the amount of the ions in such a manner that the resistance increases when the ions are discharged and the resistance decreases when the ions are occluded; and an ion conductive layer that carries the ions and is provided between the first resistance change layer and the second resistance change layer.

The invention provides a resistive memory with better area efficiency without degrading reliability, which includes an array area, word lines, a local source line, bit lines, and a shared source line. In the array area, memory cells are arranged in a matrix, and each memory cells includes a variable resistance element and an accessing transistor. The word lines extend in a row direction of the array area and are connected to the memory cells in the row direction. The local source line extends in a column direction of the array area. The bit lines extend in the column direction and are connected to first electrodes of the memory cells in the column direction. The shared source line is connected to the local source line. The shared source line extends in the row direction and is connected to second electrodes of the memory cells in the row direction.

Methods, systems, and devices for polarity-written cell architectures for a memory device are described. In an example, the described architectures may include memory cells that each include or are otherwise associated with a material configured to store one of a set of logic states based at least in part on a polarity of a write voltage applied to the material. Each of the memory cells may also include a cell selection component configured to selectively couple the material with an access line. In some examples, the material may include a chalcogenide, and the material may be configured to store each of the set of logic states in an amorphous state of the chalcogenide. In various examples, different logic states may be associated with different compositional distributions of the material of a respective memory cell, different threshold characteristics of the material of a respective memory cell, or other characteristics.

Methods, systems, and devices for polarity-written cell architectures for a memory device are described. In an example, the described architectures may include memory cells that each include or are otherwise associated with a material configured to store one of a set of logic states based at least in part on a polarity of a write voltage applied to the material. Each of the memory cells may also include a cell selection component configured to selectively couple the material with an access line. In some examples, the material may include a chalcogenide, and the material may be configured to store each of the set of logic states in an amorphous state of the chalcogenide. In various examples, different logic states may be associated with different compositional distributions of the material of a respective memory cell, different threshold characteristics of the material of a respective memory cell, or other characteristics.

Systems, methods, and apparatus related to memory devices. In one approach, a vertical three-dimensional cross-point memory device uses digit line decoders that include, on the digit line side of memory cells, a current limiter and sensing circuit configured to control program current in either of positive or negative program polarities, as selected by a controller. Two current limiters are each used on the digit line side of each memory cell. A negative polarity current limiter is used for pull-up, and a positive polarity current limiter is used for pull-down. A negative polarity sensing circuit is used between the respective digit line decoder and a positive supply voltage. A positive polarity sensing circuit is used between the respective digit line decoder and a negative supply voltage. The current limiter and sensing circuit pair of the same polarity is coupled to each digit line decoder based on the selected program polarity.

A device includes at least one tunable resistive element. Each tunable resistive element comprises a first terminal, a second terminal, and a dielectric layer arranged between the first and second terminals. The device is configured to apply at least one electrical set pulse to the resistive elements to form a conductive filament comprising a plurality of oxygen vacancies in the dielectric layer. The device is configured to apply at least one electrical reset pulse to displace a subset of the oxygen vacancies of the conductive filament. The at least one electrical reset pulse comprises a first part, which is adapted to increase the temperature of the conductive filament and increase the mobility of the oxygen vacancies of the conductive filament, and a second part, which is configured to displace the subset of the oxygen vacancies of the conductive filament.

A liquid electrochemical memory device is provided. In one aspect, the device includes a memory region for storing at least two bits, the memory region having a first volume; and a liquid electrolyte region fluidically connected to the memory region, the liquid electrolyte region having a second volume larger than the first volume. The device further includes a working electrode exposed to the memory region, and a counter electrode exposed to the liquid electrolyte region. The device also includes an electrolyte filling the memory region and the liquid electrolyte region, in physical contact with the working electrode and the counter electrode, the electrolyte including at least two conductive species. The device further includes a control unit for biasing the working electrode and the counter electrode.