Semiconductor pillars having triangular-shaped lateral peripheries, and integrated assemblies
11616079 · 2023-03-28
Assignee
Inventors
- Albert Fayrushin (Boise, ID, US)
- Augusto Benvenuti (Lallio, IT)
- Haitao Liu (Boise, ID, US)
- Xin Lan (Singapore, SG)
Cpc classification
H10B43/27
ELECTRICITY
H01L29/513
ELECTRICITY
H10B41/27
ELECTRICITY
International classification
H01L29/10
ELECTRICITY
Abstract
Some embodiments include a pillar which contains semiconductor material, and which extends primarily along a first direction. A cross-section through the pillar along a second direction orthogonal to the first direction is through the semiconductor material and includes a lateral periphery of the pillar configured as three-sided shape. Some embodiments include an integrated assembly having a vertical stack of alternating first and second levels. The first levels include conductive structures and the second levels are insulative. Channel-material-pillars extend through the vertical stack. Each of the channel-material-pillars has a top-down cross-section which includes a lateral periphery configured as three-sided shape of an equilateral triangle with rounded vertices.
Claims
1. A pillar comprising semiconductor material and extending primarily along a first direction; a cross-section through the pillar along a second direction orthogonal to the first direction being through the semiconductor material and comprising a lateral periphery of the pillar configured as a three-sided shape; a central-most material comprising rounded corners in the three-sided shape; and a charge-storage material surrounding the central-most material and comprising conductive nanodots.
2. The pillar of claim 1 wherein the pillar comprises a plurality of pillars configured as three-sided shapes, all the three-sided shapes of the plurality of pillars pointing in the same direction.
3. The pillar of claim 1 wherein the central-most material comprises a dielectric material.
4. The pillar of claim 1 extending vertically, and wherein the configuration is along a horizontal cross-section through the vertically-extending pillar.
5. The pillar of claim 1 wherein the semiconductor material is a channel material, and the pillar further comprising: a tunneling material between the channel material and the charge-storage material.
6. The pillar of claim 1 wherein the central-most material comprises silicon dioxide.
7. The pillar of claim 1 wherein the pillar comprises a hollow structure.
8. The pillar of claim 1 further comprising a gate structure proximate the pillar, the gate structure comprising a conductive core and a conductive liner surrounding the conductive core.
9. The pillar of claim 8 further comprising a dielectric-barrier layer surrounding the conductive core.
10. An integrated assembly, comprising: vertically-stacked memory cells along a vertically-extending pillar; the memory cells comprising gate structures having conductive cores with conductive liners surrounding the conductive cores; the pillar comprising a cylinder of channel material, each of the memory cells including a region of said cylinder; the cylinder having a top-down cross-section comprising a lateral periphery configured as a three-sided shape; and a central-most material within the three-side shape, the central-most material comprising rounded corners.
11. The integrated assembly of claim 10 wherein the three-sided shape has rounded corners where the sides of the three-sided shape join to one another.
12. The integrated assembly of claim 10 wherein the three-sided shape corresponds substantially to an equilateral triangle with rounded vertices.
13. The integrated assembly of claim 10 wherein the central-most material comprises silicon dioxide.
14. The integrated assembly of claim 10 wherein the vertically-extending pillar comprises a hollow structure.
15. The integrated assembly of claim 10 further comprising dielectric-barrier layers surrounding the conductive cores.
16. The integrated assembly of claim 10 wherein the channel material comprises nihonium.
17. An integrated assembly of memory cells, comprising: a plurality of vertically-extending pillars comprising a cylinder of channel material, the cylinders being hollow and having a top-down cross-section comprising a lateral periphery configured as a three-sided shape; and wherein all the three-sided shapes of the plurality of the vertically-extending pillars pointing in the same direction.
18. The integrated assembly of claim 17 wherein a central-most material within the three-side shape, the central-most material comprising rounded corners.
19. The integrated assembly of claim 17 further comprising gate structures proximate the plurality of the vertically-extending pillars, the gate structures comprising conductive cores and conductive liners surrounding the conductive cores.
20. The integrated assembly of claim 19 further comprising dielectric-barrier layers surrounding the conductive cores.
21. A pillar comprising: a cylinder of channel material, the cylinders having a top-down cross-section comprising a lateral periphery configured as a three-sided shape; wherein the channel material comprises an outer periphery opposite an inner periphery, the inner periphery comprising rounded corners; and wherein the outer periphery comprises pointed corners.
22. The pillar of claim 21 wherein the cylinder of channel material comprises a plurality of cylinders of channel material configured as three-sided shapes, all the three-sided shapes of the plurality of cylinders pointing in the same direction.
23. The pillar of claim 21 wherein the channel material comprises nihonium.
24. The pillar of claim 21 wherein the cylinder of the channel material comprises a hollow structure.
25. A pillar comprising: a cylinder of channel material, the cylinders having a top-down cross-section comprising a lateral periphery configured as a three-sided shape; wherein the channel material comprises an outer periphery opposite an inner periphery, the inner periphery comprising rounded corners; and wherein the cylinder of channel material comprises a plurality of cylinders of channel material configured as three-sided shapes, all the three-sided shapes of the plurality of cylinders pointing in the same direction.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
(10) Some embodiments include semiconductor-containing pillars (e.g., channel-material-pillars of NAND memory strings) having three-sided lateral peripheries. Some embodiments include integrated arrangements (e.g., memory arrays) comprising such semiconductor-containing pillars. Example embodiments are described with reference to
(11) Referring to
(12) The conductive structures may comprise any suitable conductive composition(s). In the illustrated embodiment, each of the conductive structures 18 comprises a core material 22 and a conductive liner-material 24 extending along an outer periphery of the core material. In some embodiments, the core material 22 may comprise, consist essentially of, or consist of tungsten; and the liner-material 24 may comprise, consist essentially of, or consist of one or both of the titanium nitride and tungsten nitride.
(13) The insulative material 20 may comprise any suitable composition(s); and in some embodiments may comprise, consist essentially of, or consist of silicon dioxide.
(14) Dielectric-barrier material 26 extends along an outer periphery of the liner-material 24. The dielectric-barrier material 26 may comprise any suitable composition(s); and in some embodiments may comprise, consist essentially of, or consist of one or more high-k materials. The term “high-k” means a dielectric constant greater than that of silicon dioxide (i.e., greater than 3.9). Example high-k materials are aluminum oxide, hafnium oxide, zirconium oxide, etc.
(15) The stack 12 is supported over a source structure 28. The source structure 28 may comprise any suitable electrically conductive composition(s); such as, for example, one or more of various metals (e.g., titanium, tungsten, cobalt, nickel, platinum, ruthenium, etc.), metal-containing compositions (e.g., metal silicide, metal nitride, metal carbide, etc.), and/or conductively-doped semiconductor materials (e.g., conductively-doped silicon, conductively-doped germanium, etc.). In some embodiments, the source structure 28 may comprise conductively-doped silicon over tungsten silicide. The source structure 28 may be analogous to the structures 216 described above in the Background section of this disclosure.
(16) The source structure is shown to be over an insulative material 30. The insulative material 30 may comprise any suitable composition(s); and in some embodiments may comprise one or more of silicon dioxide, silicon nitride, etc.
(17) The insulative material 30 is supported by a base 32. The base 32 may comprise semiconductor material; and may, for example, comprise, consist essentially of, or consist of monocrystalline silicon. The base 32 may be referred to as a semiconductor substrate. The term “semiconductor substrate” means any construction comprising semiconductive material, including, but not limited to, bulk semiconductive materials such as a semiconductive wafer (either alone or in assemblies comprising other materials), and semiconductive material layers (either alone or in assemblies comprising other materials). The term “substrate” refers to any supporting structure, including, but not limited to, the semiconductor substrates described above. In some applications, the base 32 may correspond to a semiconductor substrate containing one or more materials associated with integrated circuit fabrication. Such materials may include, for example, one or more of refractory metal materials, barrier materials, diffusion materials, insulator materials, etc.
(18) The base 32 may have a planar surface 33 which extends along an illustrated horizontal y-axis.
(19) Vertically-extending pillars 34 extend through the stack 12. Each of the pillars includes channel material 36, tunneling material 38, charge-storage material 40 and charge-blocking material 42.
(20) In the illustrated embodiment, the pillars 34 extend along the z-axis direction of
(21) The channel material 36 comprises appropriately-doped semiconductor material. The semiconductor material may comprise any suitable composition(s); and in some embodiments may comprise, consist essentially of, or consist of one or more of silicon, germanium, III/V semiconductor material (e.g., gallium phosphide), semiconductor oxide, etc.; with the term III/V semiconductor material referring to semiconductor materials comprising elements selected from groups III and V of the periodic table (with groups III and V being old nomenclature, and now being referred to as groups 13 and 15). In some embodiments, the channel material 36 comprises, consist essentially of, or consists of appropriately-doped silicon.
(22) The tunneling material 38 (also referred to as insulative material or as charge-passage material) may comprise any suitable composition(s); and in some embodiments may comprise one or more of silicon dioxide, silicon nitride, silicon oxynitride, etc. The tunneling material may comprise a single composition, or may comprise a laminate of compositions, with such laminate being bandgap-engineered to achieve desired tunneling properties.
(23) The charge-storage material 40 may comprise any suitable composition(s); and in some embodiments may comprise charge-trapping material; such as, for example, silicon nitride, conductive nanodots, etc. In some embodiments, the charge-storage material 40 may comprise silicon nitride having a stoichiometry of Si.sub.3N.sub.4. In some embodiments, the charge-storage material 40 may comprise silicon and nitrogen, and may or may not have the stoichiometry of Si.sub.3N.sub.4.
(24) The charge-blocking material 42 may comprise any suitable composition(s); and in some embodiments may comprise silicon, oxygen and nitrogen (i.e., may comprise silicon oxynitride).
(25) The channel material 36 within the pillars 34 is configured as vertically-extending cylinders 44. In some embodiments, such cylinders may be referred to as channel-material-cylinders, or as channel-material-pillars. In the illustrated embodiment, the channel-material-cylinders 44 are hollow, and a dielectric material 46 is provided within the hollows in the cylinders 44. The dielectric material 46 may comprise any suitable composition(s); and in some embodiments may comprise, consist essentially of, or consist of silicon dioxide.
(26) The top-down view of
(27) In some embodiments, the channel-material-pillars 44 may be considered to have first lateral peripheries 45, and the pillars 34 may be considered to have second lateral peripheries 47 which are outward of the first lateral peripheries 45.
(28) The tunneling material 38 may be considered to be adjacent to the channel material 36, and to be configured as cylinders 49 which laterally surround the channel-material-pillars 44. The charge-storage material 40 may be considered to be adjacent to the tunneling material 38, and to be configured as cylinders 51 which laterally surround the tunneling-material-cylinders 49. The charge-blocking material 42 may be considered to be adjacent to the charge-storage material 40 and to be configured as cylinders 53 which laterally surround the charge-storage-material-cylinders 51. In the illustrated embodiment, the tunneling-material-cylinders 49 are conformal to outer surfaces of the channel-material-cylinders 44, the charge-storage-material-cylinders 51 are conformal to outer surfaces of the tunneling-material-cylinders 49, and the charge-blocking-material-cylinders 53 are conformal to outer surfaces of the charge-storage-material-cylinders 51.
(29) Vertically-stacked memory cells 50 are along the pillars 34. Each of the memory cells includes regions of the channel material 36, tunneling material 38, charge-storage material 40, charge-blocking material 42, dielectric-barrier material 26, and conductive structures 18.
(30) The portions of the conductive structures 18 within the memory cells 50 may be considered to be gating regions 52. Other portions of the conductive structures 18 which are not within the memory cells 50 may be considered to be routing regions (wordline regions) 54.
(31) The channel material 36 is shown to be electrically coupled with the source structure 28. A gap is illustrated between the source structure 28 and the stacked memory cells 50 to indicate that there may be other materials and devices between the source structure 28 and the memory cells. For instance, source-side select gates (SGSs) may be provided between the source structure 28 and the vertically-stacked memory cells 50.
(32) The stacked memory cells 50 along a pillar 34 may correspond to a string of NAND memory devices. There may be any suitable number of memory cells within each string. For instance, in some embodiments the individual strings may comprise eight memory cells, 16 memory cells, 32 memory cells, 64 memory cells, 128 memory cells, etc.
(33) The channel-material-pillars 44 may be electrically coupled to bitlines 56, which in turn may be electrically coupled with sensing circuitry (e.g., sense-amplifier-circuitry) 58. Only one of such connections is shown to simplify the drawing of
(34) The routing regions (wordline regions) 54 may be electrically coupled with wordline-driver-circuitry 60. Only one of such connections is shown to simplify the drawing of
(35) In the illustrated embodiment, the sense-amplifier-circuitry 58 and the wordline-driver-circuitry 60 are along the base 32, and beneath the memory cells 50 (i.e., beneath a memory array comprising the memory cells 50). The sense-amplifier-circuitry 58 and wordline-driver-circuitry 60 may be considered to be examples of logic circuitry (e.g., CMOS circuitry) which may be provided beneath an array of the memory cells 50. In some embodiments, at least some of the logic circuitry may be directly beneath the array of memory cells 50, and other portions of the logic circuitry may or may not be directly beneath the array of the memory cells (i.e., may be over the array of the memory cells, laterally offset relative to the array of the memory cells, etc.).
(36) The base 32 is illustrated to be spaced from the insulative material 30 by a gap to indicate that there may be additional components and materials between the base 32 and the insulative material 30. Such additional components and materials may include, for example, regions of the illustrated logic circuits 58 and 60.
(37) The top view of
(38) Insulative material 48 is shown to be laterally adjacent the arrangement of the pillars 34. The insulative material 48 may comprise any suitable composition(s); and in some embodiments may comprise, consist essentially of, or consist of silicon dioxide. The insulative material 48 may fill slits which are utilized during a gate replacement process to form the materials 26, 22 and 24 along the levels 14. The filled slits may correspond to panels which separate adjacent blocks of memory cells from one another.
(39) In some embodiments, the pillars 34 may be considered to extend primarily along a first direction (the z-axis direction of
(40) The channel-material-cylinders (channel-material pillars) 44 have three-sided shapes conformal to the three-sided shapes of the pillars 60.
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(42) An advantage of the pillars 34 having the three-sided-shaped cross-sections is that such may improve charge retention as compared to conventional pillars having circular-shaped cross-sections, while maintaining rapid program/erase speeds. Specifically, the rounded vertices 62, 64 and 66 may provide pockets for retaining charge. Such mechanism is provided to assist the reader an understanding the invention. The suggested mechanism is not to limit this disclosure or the claims that follow in any manner, except to the extent, if any, that such mechanism is expressly recited in the claims.
(43) In some embodiments, the three-sided shapes 60 may be based on an original circular shape of a conventional pillar, and may be formed so that they may be packed to about the same density as the conventional pillar. Accordingly, the advantages of the three-sided shapes may be achieved without adversely influencing packing density. In some embodiments, the three-sided shapes 60 may be based on an original circular shape of a conventional pillar, and may be formed to be packed to a tighter density than the conventional pillar, to the same density as the conventional pillar, or to a looser density than the conventional pillar.
(44) An example method for generating a suitable three-sided shape 60 is described with reference to
(45) Referring to
(46) Referring to
(47) Referring to
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(49) Referring to
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(52) The shape 60 may be tailored relative to an original starting circle 72 by tailoring the size of the equilateral triangle template 74 and/or by tailoring the sizes of the circle templates 82, 84 and 86. Such is illustrated utilizing
(53) The right-side of
(54) The right-side of
(55) The right-side of
(56) The memory cells 50 described herein (
(57) The tunneling material 38 may be configured to allow desired tunneling (e.g., transportation) of charge (e.g., electrons) between the charge-storage material 40 and the channel material 36. The tunneling material may be configured (i.e., engineered) to achieve a selected criterion, such as, for example, but not limited to, an equivalent oxide thickness (EOT). The EOT quantifies the electrical properties of the tunneling material, (e.g., capacitance) in terms of a representative physical thickness. For example, EOT may be defined as the thickness of a theoretical silicon dioxide layer that would be required to have the same capacitance density as a given dielectric (e.g., tunneling material 38), ignoring leakage current and reliability considerations.
(58) The charge-blocking material 42 may provide a mechanism to block charge from flowing from the charge-storage material to the control gates.
(59) The dielectric barrier material 26 may be utilized to inhibit back-tunneling of electrons from the control gates toward the charge-storage material.
(60) The assemblies and structures discussed above may be utilized within integrated circuits (with the term “integrated circuit” meaning an electronic circuit supported by a semiconductor substrate); and may be incorporated into electronic systems. Such electronic systems may be used in, for example, memory modules, device drivers, power modules, communication modems, processor modules, and application-specific modules, and may include multilayer, multichip modules. The electronic systems may be any of a broad range of systems, such as, for example, cameras, wireless devices, displays, chip sets, set top boxes, games, lighting, vehicles, clocks, televisions, cell phones, personal computers, automobiles, industrial control systems, aircraft, etc.
(61) Unless specified otherwise, the various materials, substances, compositions, etc. described herein may be formed with any suitable methodologies, either now known or yet to be developed, including, for example, atomic layer deposition (ALD), chemical vapor deposition (CVD), physical vapor deposition (PVD), etc.
(62) The terms “dielectric” and “insulative” may be utilized to describe materials having insulative electrical properties. The terms are considered synonymous in this disclosure. The utilization of the term “dielectric” in some instances, and the term “insulative” (or “electrically insulative”) in other instances, may be to provide language variation within this disclosure to simplify antecedent basis within the claims that follow, and is not utilized to indicate any significant chemical or electrical differences.
(63) The terms “electrically connected” and “electrically coupled” may both be utilized in this disclosure. The terms are considered synonymous. The utilization of one term in some instances and the other in other instances may be to provide language variation within this disclosure to simplify antecedent basis within the claims that follow.
(64) The particular orientation of the various embodiments in the drawings is for illustrative purposes only, and the embodiments may be rotated relative to the shown orientations in some applications. The descriptions provided herein, and the claims that follow, pertain to any structures that have the described relationships between various features, regardless of whether the structures are in the particular orientation of the drawings, or are rotated relative to such orientation.
(65) The cross-sectional views of the accompanying illustrations only show features within the planes of the cross-sections, and do not show materials behind the planes of the cross-sections, unless indicated otherwise, in order to simplify the drawings.
(66) When a structure is referred to above as being “on”, “adjacent” or “against” another structure, it can be directly on the other structure or intervening structures may also be present. In contrast, when a structure is referred to as being “directly on”, “directly adjacent” or “directly against” another structure, there are no intervening structures present. The terms “directly under”, “directly over”, etc., do not indicate direct physical contact (unless expressly stated otherwise), but instead indicate upright alignment.
(67) Structures (e.g., layers, materials, etc.) may be referred to as “extending vertically” to indicate that the structures generally extend upwardly from an underlying base (e.g., substrate). The vertically-extending structures may extend substantially orthogonally relative to an upper surface of the base, or not.
(68) Some embodiments include a pillar which contains semiconductor material, and which extends primarily along a first direction. A cross-section through the pillar along a second direction orthogonal to the first direction is through the semiconductor material and includes a lateral periphery of the pillar configured as three-sided shape.
(69) Some embodiments include an integrated assembly having vertically-stacked memory cells along a vertically-extending pillar. The pillar includes a cylinder of channel material. Each of the memory cells along the pillar includes a region of said cylinder. The cylinder has a top-down cross-section having a lateral periphery configured as a three-sided shape.
(70) Some embodiments include an integrated assembly having a vertical stack of alternating first and second levels. The first levels include conductive structures and the second levels are insulative. Channel-material-pillars extend through the vertical stack. Each of the channel-material-pillars has a top-down cross-section which includes a lateral periphery configured as three-sided shape corresponding substantially to an equilateral triangle with rounded vertices.
(71) 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.