According to an embodiment, a phase-change memory device comprises: an upper electrode and a lower electrode; a phase-change layer in which a crystal state thereof is changed by heat supplied by the upper electrode and the lower electrode; and a selector which selectively switches the heat supplied by the upper electrode and the lower electrode to the phase-change layer, wherein the selector is formed of a compound which includes a transition metal in the phase-change material so as to have a high resistance when the crystalline state of the selector is crystalline and so as to have a low resistance when the crystalline state of the selector is non-crystalline.

A programmable resistive memory element and a method of adjusting a resistance of a programmable resistive memory element are provided. The programmable resistive memory element includes at least one resistive memory element. Each resistive memory element includes an Indium-Gallium-Zinc-Oxide (IGZO) resistive layer, a first electrical contact and a second electrical contact. The first and second electrical contacts are disposed on the IGZO resistive layer in the same plane. The programmable resistive memory element includes a voltage generator coupled to the first and second electrical contacts, constructed and arranged to apply a thermal treatment to the resistive memory element to adjust a resistance of the resistive memory element.

A phase-change memory cell is formed by a heater, a crystalline layer disposed above the heater, and an insulating region surrounding sidewalls of the crystalline layer. The phase-change memory cell supports programming with a least three distinct data levels based on a selective amorphization of the crystalline layer.

Disclosed herein is a memory cell. The memory cell may act both as a combined selector device and memory element. The memory cell may be programmed by applying write pulses having different polarities. Different polarities of the write pulses may program different logic states into the memory cell. The memory cell may be read by read pulses all having the same polarity. The logic state of the memory cell may be detected by observing different threshold voltages when the read pulses are applied. The different threshold voltages may be responsive to the different polarities of the write pulses.

The present disclosure includes apparatuses, methods, and systems for sensing two memory cells to determine one data value. An embodiment includes a memory having a plurality of memory cells and circuitry configured to sense memory states of each of two memory cells to determine one data value. One data value is determined by sensing the memory state of a first one of the two memory cells using a first sensing voltage in a sense window between a first threshold voltage distribution corresponding to a first memory state and a second threshold voltage distribution corresponding to a second memory state and sensing the memory state of a second one of the two memory cells using a second sensing voltage in the sense window. The first and second sensing voltages are selectably closer in the sense window to the first threshold voltage distribution or the second threshold voltage distribution.

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.

In an example, a plurality of signal pulses is applied across a plurality of memory cells concurrently until each respective memory cell reaches a desired state. Each respective memory cell is commonly coupled to a first signal line and is coupled to a different respective second signal line. Each signal pulse causes each respective memory cell to move toward the desired state by causing each respective memory cell to snap back. Current to a respective second signal line is turned off in response to each time the respective memory cell coupled thereto snaps back.

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.

A method for reading memory cell, comprising the steps of applying a first read voltage to a plurality of memory cells, detecting first threshold voltages exhibited by the plurality of memory cells in response to application of the first read voltage, based on the first threshold voltages, associating a first logic state to one or more cells of the plurality of memory cells, applying a second read voltage to the plurality of memory cells, wherein the second read voltage has the same polarity of the first read voltage and a higher magnitude than an expected highest threshold voltage of memory cells in the first logic state, detecting second threshold voltages exhibited by the plurality of memory cells in response to application of the second read voltage, based on the second threshold voltages, associating a second logic state to one or more cells of the plurality of memory cells, applying a third read voltage to the plurality of memory cells, wherein the third read voltage has the same polarity of the first and second read voltages and is applied at least to a group of memory cells that, during the application the second read voltage, have been reprogrammed to an opposite logic state, detecting third threshold voltages exhibited by the plurality of memory cells in response to application of the third read voltage, and based on the third threshold voltages, associating one of the first or second logic state to one or more of the cells of the of the plurality of memory cells. A related circuit, a related memory device and a related system are also disclosed.

A high density embedded-artificial synaptic element includes a semiconductor substrate, a select transistor, a metal layer and a memory transistor. The select transistor is disposed on the semiconductor substrate and includes a first gate structure, a drain region and a source region. The drain region and the source region are located on the opposite sides of the first gate structure. The metal layer is connected to the drain region. The memory transistor is disposed on the semiconductor substrate and includes a second gate structure, a first electrode region, a second electrode region, a first memristor and a second memristor. The second gate structure is connected to the metal layer. The first memristor is formed between the second gate structure and the first electrode region. The second memristor is formed between the second gate structure and the second electrode region.