Apparatuses including memory cells and methods of operation of same
Disclosed herein is a memory cell including a memory element and a selector device. The memory cell may be programmed with a programming pulse having a first polarity and read with a read pulse having a second polarity. The memory cell may be programmed with a programming pulse having first and second portions. The first and second portions may have different magnitudes and polarities. The memory cell may exhibit reduced voltage drift and/or threshold voltage distribution. Described herein is a memory cell that acts as both a memory element and a selector device. The memory cell may be programmed with a programming pulse having first and second portions. The first and second portions may have different magnitudes and polarities.
1. An apparatus, comprising:
a memory cell comprising:
a memory element; and
a selector device coupled to the memory element;
a first memory access line coupled to the memory cell;
a second memory access line coupled to the memory cell; and
a control logic configured to provide control signals for a programming pulse of the memory cell and the selector device,
wherein a portion of the programming pulse is provided to the memory cell to change a material concentration in the selector device, and
wherein the another portion of the programming pulse is provided to program a logic state of the memory element.
2. The apparatus of claim 1 , wherein the other portion of the programming pulse provided to program the logic state of the memory element comprises a current magnitude or a voltage magnitude.
3. The apparatus of claim 1 , wherein the portion of the programming pulse that is configured to change the material concentration in the selector device comprises a first polarity and the other portion of the programming pulse provided to program the logic state of the memory element comprises a second polarity.
4. The apparatus of claim 1 , wherein the first memory access line and the second memory access line are set to either a forward polarity or reverse polarity.
5. The apparatus of claim 1 , wherein the portion of the programming pulse that is configured to change the material concentration in the selector device corresponds to a change to a uniform concentration of a material in the selector device.
6. The apparatus of claim 5 , wherein the change in the uniform concentration of the material in the selector device includes a change to the material in a top portion of the selector device and a change to the material in a bottom portion of the selector device.
7. The apparatus of claim 6 , wherein the change to the material in the top portion of the selector device corresponds to changing the top portion of the selector device to have a higher concentration of Se than As in the material comprising an As—Se alloy.
8. The apparatus of claim 6 , wherein the change to the material in the bottom portion of the selector device corresponds to changing the bottom portion of the selector device to have a higher concentration of As than Se in the material comprising an As—Se alloy.
9. The apparatus of claim 5 , wherein the portion of the programming pulse that is configured to change the material concentration in the selector device includes not changing a material concentration of the memory element, such that a material concentration of the memory element remains substantially uniform.
10. The apparatus of claim 5 , wherein the portion of the programming pulse that is configured to change the material concentration in the selector device comprises a current magnitude or a voltage magnitude.
11. The apparatus of claim 1 , wherein the memory element comprises a phase change material and the programming pulse is configured by the control logic to change a phase of at least a portion of the phase change material.
12. An apparatus, comprising:
a memory element configured to receive a programming pulse including a portion to write a logic state to the memory element; and
a selector device coupled to the memory element and configured to receive the programming pulse,
wherein another portion of the programming pulse having substantially a same duration as the portion of the programming pulse causes a change to a material state in the selector device.
13. The apparatus of claim 12 , wherein the memory element is configured to receive a read pulse across the memory cell, the read pulse comprising a square shape, a triangular shape, a trapezoidal shape, a staircase shape, or a sinusoidal shape.
14. The apparatus of claim 12 , further comprising a memory array including a plurality of memory cells and a plurality of memory access lines coupled to at least some of the plurality of memory cells, wherein the memory element and selector device are included in a memory cell of the plurality of memory cells.
15. The apparatus of claim 12 , wherein the memory array is a two-dimensional array (2D) or a three-dimensional (3D) array.
16. The apparatus of claim 12 , wherein the selector device comprises a chalcogenide material.
17. A method comprising:
applying a portion of a programming pulse across a memory cell; and
applying another portion of the programming pulse to change a material of a selector device coupled to the memory cell,
wherein applying the another portion of the programming pulse to change the material of the selector device comprises altering a material concentration of the selector device.
18. The method of claim 17 , wherein applying the portion of the programming pulse across the memory cell comprises writing a logic state to the memory cell.