Methods, systems, and devices for time-based access of memory cells in a memory array are described herein. During a sense portion of a read operation, a selected memory cell may be charged to a predetermined voltage level. A logic state stored on the selected memory cell may be identified based on a duration between the beginning of the charging and when selected memory cell reaches the predetermined voltage level. In some examples, time-varying signals may be used to indicate the logic state based on the duration of the charging. The duration of the charging may be based on a polarization state of the selected memory cell, a dielectric charge state of the selected state, or both a polarization state and a dielectric charge state of the selected memory cell.

A device comprises a non-volatile memory and a control system. The non-volatile memory includes an array of non-volatile memory cells, wherein at least one non-volatile memory cell includes a ferroelectric field-effect transistor (FeFET) device. The FeFET device includes first and second source/drain regions, and a gate structure which comprises a ferroelectric layer, and a gate electrode disposed over the ferroelectric layer. The ferroelectric layer comprises a first region adjacent to the first source/drain region and a second region adjacent to the second source/drain region. The control system is operatively coupled to the non-volatile memory to program the FeFET device to have a logic state among a plurality of different logic states. At least one logic state among the plurality of different logic states corresponds to a polarization state of the FeFET device in which the first and second regions of the ferroelectric layer have respective remnant polarizations with opposite polarities.

Methods, systems, techniques, and devices for operating a ferroelectric memory cell or cells are described. A first ferroelectric memory cell may be used to charge a second ferroelectric memory cell by transferring charge from a plate of first ferroelectric memory cell to a plate of the second ferroelectric memory cell. In some examples, prior to the transfer of charge, the first ferroelectric memory cell may be selected for a first operation in which the first ferroelectric memory cell transitions from a charged state to a discharged state and the second ferroelectric memory cell may be selected for a second operation during which the second ferroelectric memory cell transitions from a discharged state to a charged state. The discharging of the first ferroelectric memory cell may be used to assist in charging the second ferroelectric memory cell.

A circuit structure includes a first ferroelectric field effect transistor (FeFET) having a first gate electrode, a first source electrode, and a first drain electrode and a second FeFET having a second gate electrode, a second source electrode, and a second drain electrode. The first gate electrode is connected to a wordline, and the first source electrode and the second source electrode are connected to a bitline. The first drain electrode is connected to the second gate electrode and the second drain electrode is connected to a bias line. A weight synapse structure is constructed by combining two circuit structures. A plurality of weight synapse structures are incorporated into a crossbar array.

Structures including non-volatile memory elements and methods of fabricating a structure including non-volatile memory elements. First, second, and third non-volatile memory elements each include a first electrode, a second electrode, and a switching layer between the first electrode and the second electrode. A first bit line is coupled to the first electrode of the first non-volatile memory element and to the first electrode of the second non-volatile memory element. A second bit line is coupled to the first electrode of the third non-volatile memory element.

Memory cells are described that include two reference voltages that may store and sense three distinct memory states by compensating for undesired intrinsic charges affecting a memory cell. Although embodiments described herein refer to three memory states, it should be appreciated that in other embodiments, the memory cell may store or sense more than three charge distributions using the described methods and techniques. In a first memory state, a programming voltage or a sensed voltage may be higher than a first reference voltage and a second reference voltage. In a second memory state, the applied voltage or the sensed voltage may be between the first and the second reference voltages. In a third memory state, the applied voltage or the sensed voltage may be lower than the first and the second reference voltages. As such, the memory cell may store and retrieve three memory states.

Some embodiments include apparatuses, and methods of forming and operating the apparatuses. Some of the apparatuses include a conductive line, non-volatile memory cells of a first memory cell type, the non-volatile memory cells coupled in series among each other, and an additional non-volatile memory cell of a second memory cell type coupled to the conductive line and coupled in series with the non-volatile memory cells of the first memory cell type. The second memory cell type is different from the first memory cell type.

Methods, systems, and apparatuses for self-referencing memory cells are described. A reference value for a cell may be created through multiple sense operations on the cell. The cell may be sensed several times and an average of at least two sensing operations may be used as a reference for another sense operation. For example, the cell may be sensed and the resulting charge stored at a capacitor. The cell may be biased to one state, sensed a second time, and the resulting charge stored at another capacitor. The cell may be biased to another state, sensed a third time, and the resulting charge stored to another capacitor. The values from the second and third sensing operations may be averaged and used as a reference value in a comparison with value of the first sensing operation to determine a logic state of the cell.

A semiconductor device includes a substrate including an active region extending in a first direction, a gate electrode on the substrate and extending in a second direction, and a plurality of channel layers on the active region. The plurality of channel layers are spaced apart from each other in a third direction perpendicular to an upper surface of the substrate. The device includes a plurality of dielectric layers between the plurality of channel layers and the gate electrode, the plurality of dielectric layers include at least one of a ferroelectric material or an anti-ferroelectric material, and each of the plurality of dielectric layers has a different coercive voltage. The device includes source/drain regions in recess regions in which the active region is recessed, the source/drain regions are on both sides of the gate electrode, and the source/drain regions are in contact with the plurality of channel layers.

An electronic device including a semiconductor memory is provided. The semiconductor memory includes a plurality of first lines extending in a first direction; a plurality of second lines disposed over the first lines, the second lines extending in a second direction crossing the first direction; a plurality of memory cells disposed between the first lines and the second lines at intersection regions of the first lines and the second lines; first liner layer patterns positioned on both sidewalls of each memory cell in the second direction; a first insulating layer pattern positioned between adjacent first liner layer patterns in the second direction; second liner layer patterns positioned on both sidewalls of each memory cell in the first direction; a second insulating layer pattern positioned between adjacent second liner layer patterns in the first direction; and a third insulating layer positioned between adjacent second liner layer patterns in the second direction.