Array Of Cross Point Memory Cells And Methods Of Forming An Array Of Cross Point Memory Cells
20170330881 · 2017-11-16
Inventors
Cpc classification
H10B63/20
ELECTRICITY
H10B53/00
ELECTRICITY
H10N70/882
ELECTRICITY
H10N70/826
ELECTRICITY
H10B63/80
ELECTRICITY
H10N70/231
ELECTRICITY
International classification
Abstract
A method of forming an array of cross point memory cells comprises using two, and only two, masking steps to collectively pattern within the array spaced lower first lines, spaced upper second lines which cross the first lines, and individual programmable devices between the first lines and the second lines where such cross that have an upwardly open generally U-shape vertical cross-section of programmable material laterally between immediately adjacent of the first lines beneath individual of the upper second lines. Arrays of cross point memory cells independent of method of manufacture are disclosed.
Claims
1. A method of forming an array of cross point memory cells, comprising: using two, and only two, masking steps to collectively pattern within the array spaced lower first lines, spaced upper second lines which cross the first lines, and individual programmable devices between the first lines and the second lines where such cross that have an upwardly open generally U-shape vertical cross-section of programmable material laterally between immediately adjacent of the first lines beneath individual of the upper second lines.
2. The method of claim 1 wherein a last of the two masking steps collectively final patterns material of each of said second lines and said individual programmable devices within the array.
3. The method of claim 1 comprising: using a first of the two masking steps to pattern the first lines and form trenches there-between; and forming programmable material of the programmable devices longitudinally alongside the first lines within the trenches.
4. The method of claim 3 comprising forming conductive electrode material of the programmable devices longitudinally along the programmable material.
5. The method of claim 1 comprising: using a first of the two masking steps to pattern the first lines and form trenches there-between; lining the trenches with programmable material of the programmable devices to less-than-fill the trenches; and lining the programmable material-lined trenches with conductive electrode material of the programmable devices to less-than-fill the programmable material-lined trenches.
6. The method of claim 5 comprising anisotropically etching the conductive electrode material selectively relative to the programmable material to form spaced walls of the conductive electrode material and expose programmable material there-between.
7. The method of claim 6 comprising elevationally recessing the spaced walls relative to programmable material.
8. The method of claim 7 comprising forming the select device material of individual of the memory cells within recesses formed by said elevationally recessing, the select device material comprising an upwardly open generally U-shape in vertical cross-section orthogonal the first lines.
9. The method of claim 1 comprising using said two masking steps to also pattern select device material that is between the programmable devices and the upper second lines.
10. The method of claim 9 comprising forming the select device material of individual of the memory cells to underlie individual ones of the second lines and to comprise an upwardly open generally U-shape in vertical cross-section along its overlying second line.
11. The method of claim 9 comprising: using a first of the two masking steps to pattern the first lines and form trenches there-between; lining the trenches with programmable material of the programmable devices to less-than-fill the trenches; lining the programmable material-lined trenches with conductive electrode material of the programmable devices to less-than-fill the programmable material-lined trenches; lining uppermost portions of the programmable material-lined trenches with select device material to less-than-fill the uppermost portions of the programmable material-lined trenches; lining the select device material-lined trenches with conductive electrode material to less-than-fill the select device material-lined trenches; and anisotropically etching the conductive electrode material to the select device material to form spaced walls of the conductive electrode material and expose select device material there-between.
12. The method of claim 11 wherein the etching is conducted selectively relative to the select device material and etching is not conducted completely there-through prior to depositing material of the upper second lines.
13. The method of claim 11 comprising etching completely through the select device material using the spaced walls as a mask prior to depositing material of the upper second lines.
14. An array of cross point memory cells comprising: spaced lower first lines, spaced upper second lines which cross the first lines, and an individual memory cell between the first lines and the second lines where such cross, the individual memory cells comprising: a select device and a programmable device in series with each other, the select device being electrically coupled to one of the second lines, the programmable device being electrically coupled to the select device and one of the first lines, the select device comprising an upwardly open generally U-shape of select device material in a vertical cross-section along its overlying second line; and the programmable device comprising: a first electrode electrically coupled to one of the first lines; programmable material laterally aside the first electrode and the one first line; and a second electrode laterally aside the programmable material and electrically coupled to the select device.
15. The array of claim 14 wherein the first electrode is part of the one first line wherein no portion thereof projects laterally relative to the one first line.
16. The array of claim 14 wherein individual ones of the generally U-shaped select device material are shared by two different immediately adjacent memory cells along said overlying second line.
17. The array of claim 16 wherein laterally outer sidewalls of the individual ones of the generally U-shaped select device material are aside and directly against the programmable material of said two immediately adjacent memory cells.
18. The array of claim 16 comprising a shared electrode within the individual ones of the generally U-shaped select device material that is electrically coupled with said overlying second line and shared by said two immediately adjacent memory cells.
19. The array of claim 18 wherein the shared electrode does not comprise an upwardly open generally U-shape in the vertical cross-section.
20. The array of claim 18 wherein the shared electrode comprises an upwardly open generally U-shape in the vertical cross-section.
21. The array of claim 16 wherein the individual ones of the generally U-shaped select device material contain two non-shared electrodes that are each electrically coupled with said overlying second line.
22. The array of claim 14 wherein the programmable material comprises an upwardly open generally U-shape in the vertical cross-section, individual ones of the generally U-shaped select device material being laterally within individual ones of the generally U-shaped programmable material.
23. The array of claim 14 wherein the second electrode is directly against an elevationally innermost surface of the generally U-shaped select device material in the vertical cross-section.
24. The array of claim 14 wherein the select device material is not generally U-shaped in any vertical cross-section parallel its immediately adjacent first lines.
25. An array of cross point memory cells comprising: spaced lower first lines, spaced upper second lines which cross the first lines, and an individual memory cell between the first lines and the second lines where such cross, the individual memory cells comprising: a select device and a programmable device in series with each other, the select device being electrically coupled to one of the second lines, the programmable device being electrically coupled to the select device and one of the first lines; and the programmable device comprising: a first electrode electrically coupled to one of the first lines; programmable material laterally aside the first electrode and the one first line, the programmable material being laterally between the one first line and a first line immediately adjacent thereto and comprising an upwardly open generally U-shape in a vertical cross-section along its overlying second line; and a second electrode laterally aside the programmable material and electrically coupled to the select device.
26. An array of cross point memory cells comprising: spaced lower first lines, spaced upper second lines which cross the first lines, and an individual memory cell between the first lines and the second lines where such cross, the individual memory cells comprising: a select device and a programmable device in series with each other, the select device being electrically coupled to one of the second lines, the programmable device being electrically coupled to the select device and one of the first lines, the select device comprising a general L-shape of select device material in a vertical cross-section along its overlying second line; and the programmable device comprising: a first electrode electrically coupled to one of the first lines; programmable material laterally aside the first electrode and the one first line; and a second electrode laterally aside the programmable material and electrically coupled to the select device.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS
[0020] Embodiments of the invention encompass an array of cross point memory cells and methods of forming an array of cross point memory cells.
[0021] Materials may be aside, elevationally inward, or elevationally outward of the
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[0023] Individual memory cells 12 comprise a select device 18 and a programmable device 20 in series (i.e., electrical) with each other. Example current flow paths 45 for individual memory cells relative to first lines 14 and second lines 16 through select device 18 and programmable device 20 are shown by way of example. First lines 14 and second lines 16 are elevationally otherwise separated by intervening insulator material 25 (e.g., silicon dioxide and/or silicon nitride).
[0024] Any existing or yet-to-be developed select devices may be used, for example a junction device or a diode. Example diodes include PN diodes, PIN diodes, Schottky diodes, Zener diodes, avalanche diodes, tunnel diodes, diodes having more than three materials, metal-semiconductor-metal based tunnel diodes, threshold switches, chalcogenide based threshold switches, etc. Select device 18 is electrically coupled to one of second lines 16. Programmable device 20 is electrically coupled to select device 18 and one of first lines 14. In one embodiment, select device 18 is directly electrically coupled to the one second line and in one embodiment programmable device 20 is directly electrically coupled to both the one first line 14 and select device 18. In this document, two electronic devices or components are “electrically coupled” to one another if in normal operation electric current is capable of continuously flowing from one to the other, and does so predominately by movement of subatomic positive and/or negative charges when such are sufficiently generated. Another electronic component may be between and electrically coupled to the two electrically coupled electronic components or devices. In contrast, when two electronic components or devices are referred to as being “directly electrically coupled”, no intervening electronic component is between the two directly electrically coupled components or devices.
[0025] Individual programmable devices 20 comprise a first electrode 22 electrically coupled with (in one embodiment and as shown also comprising a portion of) one of first lines 14. A programmable material 28 is laterally aside first electrode 22 and the one first line 14. Any existing or yet-to-be-developed programmable material may be used, for example those described in the “Background” section above. In one embodiment, programmable device 20 is a ferroelectric capacitor with programmable material 28 thereby comprising ferroelectric material. Programmable device 20 also includes a second electrode 30 laterally aside programmable material 28 (in one embodiment directly there-against) and electrically coupled to select device 18. Any suitable conductive material(s) may be used for either first or second electrodes 22 and 30, with TiN being one example. In one embodiment and as shown, first electrode 22 is part of the one first line 14 wherein no portion thereof projects laterally relative to the one first line 14.
[0026] In one embodiment, select device 18 comprises an upwardly opening generally U-shape 21 of select device material 19 in a vertical cross-section along its overlying second line (e.g., along the front-depicted second line 16 in
[0027] In one embodiment, programmable material 28 is laterally between one first line 14 and a first line 14 immediately adjacent thereto. In one embodiment, programmable material 28 comprises an upwardly open generally U-shape 33 in the vertical cross-section along its overlying second line 16. Individual ones of select device material 19 of generally U-shape 21 are laterally within individual ones of programmable material 28 of generally U-shape 33. In one embodiment, individual ones of generally U-shaped programmable material 19 contain two physically separated second electrodes 30 of two different programmable devices 20 of immediately adjacent memory cells 12 along the overlying second line 16. Insulator material 32 (e.g., silicon dioxide and/or silicon nitride) is shown laterally between second electrodes 30.
[0028] In one embodiment, programmable material 28 is not generally U-shaped in any vertical cross-section parallel its laterally aside one first line 14. In one embodiment, programmable material 28 is discontinuous between individual memory cells along the one and immediately adjacent first lines. In one embodiment, the generally U-shaped programmable material 28 has external sidewalls 35 that are directly against longitudinally elongated sidewalls 37 of the one and immediately adjacent first lines 14. In one embodiment, programmable material 28 and select device 18 have respective elevationally outermost tops 39 and 41, respectively, that are planar and in one embodiment that are elevationally coincident. In one embodiment, second electrode 30 is directly against an elevationally innermost surface 23 of generally U-shaped select device material 19 in the vertical cross-section along its overlying second line 16.
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[0034] Embodiments of the invention encompass methods of forming an array of cross point memory cells and example embodiments of which are next described with reference to
[0035] A method of forming an array of cross-point memory cells in accordance with an embodiment of the invention comprises using two, and only two, masking steps to collectively pattern within the array spaced lower first lines, spaced upper second lines which cross the first lines, and individual programmable devices between the first lines and the second lines where such cross and that have an upwardly open generally U-shape vertical cross-section of programmable material laterally between immediately adjacent of the first lines beneath individual of the upper second lines. In one embodiment, select device material is between the programmable devices and the upper second lines and the two masking steps are used to also pattern the select device material. In one embodiment, a last of the two masking steps collectively final patterns material of each of the second lines and the individual programmable devices within the array.
[0036] Referring to
[0037] Referring to
[0038] In one embodiment, programmable material of the programmable devices is formed longitudinally alongside the first lines within the trenches. In one such embodiment, conductive electrode material of the programmable devices is formed longitudinally along the programmable material. As examples,
[0039] Referring to
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[0042] As alternate example method embodiments, the select device material-lined trenches may be lined with conductive electrode material 26 to less-than-fill the select device material-lined trenches, for example to produce the generally upwardly open U-shape 47 as shown with respect to conductive electrode material 26a in
CONCLUSION
[0043] In some embodiments, a method of forming an array of cross point memory cells comprises using two, and only two, masking steps to collectively pattern within the array spaced lower first lines, spaced upper second lines which cross the first lines, and individual programmable devices between the first lines and the second lines where such cross that have an upwardly open generally U-shape vertical cross-section of programmable material laterally between immediately adjacent of the first lines beneath individual of the upper second lines.
[0044] In some embodiments, an array of cross point memory cells comprises spaced lower first lines, spaced upper second lines which cross the first lines, and an individual memory cell between the first lines and the second lines where such cross. The individual memory cells comprise a select device and a programmable device in series with each other. The select device is electrically coupled to one of the second lines. The programmable device is electrically coupled to the select device and one of the first lines. The select device comprises an upwardly open generally U-shape of select device material in a vertical cross-section along its overlying second line. The programmable device comprises a first electrode electrically coupled to one of the first lines, programmable material laterally aside the first electrode and the one first line, and a second electrode laterally aside the programmable material and electrically coupled to the select device.
[0045] In some embodiments, an array of cross point memory cells comprises spaced lower first lines, spaced upper second lines which cross the first lines, and an individual memory cell between the first lines and the second lines where such cross. The individual memory cells comprise a select device and a programmable device in series with each other. The select device is electrically coupled to one of the second lines. The programmable device is electrically coupled to the select device and one of the first lines. The programmable device comprises a first electrode electrically coupled to one of the first lines, programmable material laterally aside the one first line (the programmable material being laterally between the one first line and a first line immediately adjacent thereto and comprising an upwardly open generally U-shape in a vertical cross-section along its overlying second line), and a second electrode laterally aside the programmable material and electrically coupled to the select device.
[0046] In some embodiments, an array of cross point memory cells comprises spaced lower first lines, spaced upper second lines which cross the first lines, and an individual memory cell between the first lines and the second lines where such cross. The individual memory cells comprise a select device and a programmable device in series with each other. The select device is electrically coupled to one of the second lines. The programmable device is electrically coupled to the select device and one of the first lines. The select device comprises a general L-shape of select device material in a vertical cross-section along its overlying second line. The programmable device comprises a first electrode electrically coupled to one of the first lines, programmable material laterally aside the first electrode and the one first line, and a second electrode laterally aside the programmable material and electrically coupled to the select device.
[0047] In compliance with the statute, the subject matter disclosed herein has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the claims are not limited to the specific features shown and described, since the means herein disclosed comprise example embodiments. The claims are thus to be afforded full scope as literally worded, and to be appropriately interpreted in accordance with the doctrine of equivalents.