1. A monolithic, three-dimensional memory device, comprising:
a substrate having a major surface;
a plurality of electrically conductive word lines over the major surface of the substrate, wherein each word line is elongated in a first direction that is substantially parallel to the major surface of the substrate and the plurality of word lines are spaced apart from one another in a second direction that is substantially perpendicular to the major surface of the substrate, and an electrically insulating material is located between each of the spaced apart word lines;
an electrically conductive bit line extending in a direction substantially perpendicular to the major surface of the substrate and adjacent to each of the plurality of word lines;
a non-volatile memory element material located between the bit line and each of the plurality of word lines; and
a plurality of middle electrodes comprising an electrically conductive material located between the bit line and each of the plurality of word lines, wherein the plurality of middle electrodes are discrete electrodes which are isolated from one another in at least the second direction.
2. The device of claim 1, further comprising:
a non-linear element located between the bit line and each of the plurality of word lines.
3. The device of claim 2, wherein each of the middle electrodes is adjacent to the non-volatile memory element material and electrically connects the non-volatile memory element material in series with the non-linear element.
4. The device of claim 2, wherein the non-linear element comprises a Schottky junction.
5. The device of claim 2, wherein the non-linear element comprises a tunnel junction.
6. The device of claim 2, wherein the non-linear element comprises a metal-insulator-metal (MIM) junction.
7. The device of claim 2, wherein the non-linear element is formed by providing a layer of insulating material over at least one side surface of the bit line.
8. The device of claim 1, wherein the plurality of middle electrodes are located between the non-volatile memory element material and the bit line.
9. The device of claim 1, wherein the plurality of middle electrodes are located between the non-volatile memory element and the word lines.
10. The device of claim 1, wherein the bit line comprises a generally pillar-shaped structure having at least one side surface, and the non-volatile memory element material comprises a continuous layer that extends over a side surface of the bit line and adjacent to each of the plurality of word lines.
11. The device of claim 10, wherein:
the layer of non-volatile memory element material comprises a plurality of clam shape portions adjacent to each of the plurality of word lines;
each of the clam shape portions surrounds a respective one of the plurality of middle electrodes on three sides;
the bit line comprises the generally pillar-shaped structure having a substantially rectangular cross section;
the non-linear element is located adjacent to all four sidewalls of the substantially-pillar shaped bit line; and
the a plurality of middle electrodes are located adjacent to two of four sidewalls of the substantially-pillar shaped bit lines.
12. The device of claim 1, wherein the monolithic, three-dimensional memory device comprises a ReRAM memory device.
13. The device of claim 1, wherein the electrically conductive bit line comprises a local bit line that is electrically connected to a global bit line via a select transistor.
14. The device of claim 1, wherein the non-volatile memory element material comprises a material in which discrete regions of the material located between the bit line and each of the plurality of word lines are controllably alternated between a more conductive state and a less conductive state by appropriate voltages applied to the bit line and the respective word line.
15. The device of claim 14, wherein the non-volatile memory element material comprises a metal oxide.
16. A method of fabricating a memory device, comprising:
providing a stack of alternating layers of a first material and a second material different than the first material over a major surface of a substrate, the first material comprising an electrically conductive word line material and the second material comprising an electrically insulating material;
etching the stack through a mask to form at least one opening having a sidewall defined by the alternating layers of the first material and the second material;
selectively removing the first material relative to the second material through the opening to provide a plurality of recessed portions along the sidewall of the opening;
forming a non-volatile memory element material over the sidewall of the opening and within the recessed portions;
forming an electrically conductive electrode material over the non-volatile memory element material and filling the recessed portions along the sidewall of the opening;
removing a portion of the electrically conductive electrode material from the opening to provide a plurality of isolated electrodes within the recessed portions; and
forming an electrically conductive bit line material within the opening.
17. The method of claim 16, further comprising:
forming a non-linear element between each of the plurality of electrodes and the bit line material within the opening.
18. The method of claim 17, wherein forming a non-linear element comprises forming a layer of insulating material over the non-volatile memory element material and the plurality of electrodes on the sidewall of the opening, wherein the bit line material is formed in the opening over the layer of insulating material.
19. The method of claim 17, wherein the non-linear element comprises a Schottky junction.
20. The method of claim 17, wherein the non-linear element comprises a tunnel junction.
21. The method of claim 17, wherein the non-linear element comprises a metal-insulator-metal (MIM) junction.
22. The method of claim 17, wherein etching the stack through a mask to form at least one opening comprises etching the stack to form a plurality of trenches extending in a first direction substantially parallel to the major surface of the substrate, wherein the layers of the first material in the stack form a plurality of word lines defined between adjacent trenches and elongated in the first direction, and the word lines are spaced apart in a second direction substantially perpendicular to the major surface of the substrate by the alternating layers of the second material.
23. The method of claim 22, wherein each trench comprises two opposing sidewalls defined by the alternating layers of the first material and the second material, wherein the recessed portions are formed along both opposing sidewalls, and the non-volatile memory element material is formed over both opposing trench sidewalls and within the recessed portions.
24. The method of claim 23, further comprising:
filling the plurality of trenches with an insulating material; and
etching the insulating material through a mask to form a plurality of bit line openings in the trench separated by the insulating material, wherein the non-volatile memory element material is exposed on two opposing sidewalls of the bit line openings.
25. The method of claim 24, wherein forming the electrically conductive electrode material comprises at least partially filling the bit line openings with the electrode material, and removing a portion of the electrode material comprises etching the electrode material, stopping the etching at the non-volatile memory element material and the insulating material while leaving isolated portions of the electrode material within the recessed portions along the opposing sidewalls of the bit line openings.
26. The method of claim 25, further comprising:
slimming the mask after the step of at least partially filling the bit line openings with the electrode material and after the step of etching the electrode material; and
forming a layer of an insulating material over the non-volatile memory element material and the isolated electrodes along the sidewalls of the bit line openings to form the non-linear element.
27. The method of claim 26, wherein the layer of insulating material is formed via atomic layer deposition (ALD) over all sidewalls of the bit line opening.
28. The method of claim 25, wherein:
forming the electrically conductive bit line material comprises depositing the bit line material within the bit line openings to form a plurality of substantially-pillar shaped bit lines having a substantially rectangular cross section;
the non-linear element is located adjacent to all four sidewalls of the substantially-pillar shaped bit lines; and
the isolated portions of the electrode material are located adjacent to two of four sidewalls of the substantially-pillar shaped bit lines.
29. The method of claim 17, wherein selectively removing the first material relative to the second material comprises etching through the opening using an etching process having a higher etching rate for the first material than for the second material of the stack of alternating layers.
30. The method of claim 17, wherein the memory device comprises a ReRAM memory device.
31. A method of fabricating a memory device, comprising:
providing a stack of alternating layers of a first material and a second material different than the first material over a major surface of a substrate, the first material comprising an electrically conductive word line material and the second material comprising an electrically insulating material;
etching the stack through a mask to form at least one opening having a sidewall defined by the alternating layers of the first material and the second material;
selectively removing the first material relative to the second material through the opening to provide a plurality of recessed portions along the sidewall of the opening;
forming a non-linear element material over the sidewall of the opening and within the recessed portions;
forming an electrically conductive electrode material over the non-linear memory element material and filling the recessed portions along the sidewall of the opening;
removing a portion of the electrically conductive electrode material from the opening to provide a plurality of isolated electrodes within the recessed portions;
forming a non-volatile memory element material over the sidewall of the opening and adjacent to the plurality of isolated electrodes; and
forming an electrically conductive bit line material within the opening and adjacent to the non-volatile memory element material.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A fuel cell, comprising:
a fuel electrode;
an oxidant electrode;
a fuel supply port; and
a porous material layer for transferring a liquid fuel from the fuel supply port to the fuel electrode;
wherein the porous material layer has different values of at least one of a porosity, a permeability and a tortuosity factor depending on the distance of a site of the porous material layer from at least one of the fuel supply port and the fuel electrode.
2. The fuel cell according to claim 1, wherein the porous material layer includes a plurality of porous material members, and at least one of the porous material members is arranged in contact with the fuel electrode; and
the farther from the fuel supply port, the higher value of at least one of the porosity and the permeability of the porous material member in contact with the fuel electrode or the lower value of the tortuosity factor of the porous material member in contact with the fuel electrode.
3. The fuel cell according to claim 1, wherein the porous material layer contains particles having a diameter d, and the relationship between the diameter d of the particle and at least one of the porosity and the permeability of the porous material layer satisfies formula (1) given below:
d
=
C
\xd7
K
\u2061
(
1
–
\u025b
)
2
\u025b
3
(
1
)
where d denotes the particle diameter, \u03b5 denotes the porosity, K denotes the permeability, and C denotes a proportional constant falling within a range of between the proportional constant of Carman-Kozeny formula and the proportional constant of Blake-Kozeny formula including the proportional constant of Carman-Kozeny formula and the proportional constant of Blake-Kozeny formula.
4. The fuel cell according to claim 1, wherein the porous material layer includes a laminate prepared by stacking a plurality of porous material members, at least one of the porous material members having different values of at least one of the porosity, the permeability and the tortuosity factor from the other porous material members, and having the thickness to be gradually increased or decreased depending on the distance from the fuel supply port.
5. The fuel cell according to claim 1, wherein the porous material layer includes a plurality of porous material members, and the thickness of at least one of the porous material members is gradually decreased with increase in the distance from the fuel supply port.
6. The fuel cell according to claim 1, wherein the porous material layer includes a laminate prepared by stacking a first porous material member having the thickness gradually increased with increase in the distance from the fuel supply port, and a second porous material member smaller than the first porous material member in at least one of the porosity and the permeability, and having the thickness gradually decreased with increase in the distance of a site of the second porous material member from the fuel supply port.
7. The fuel cell according to claim 1, wherein the porous material layer includes a plurality of porous material members differing from each other in at least one of the porosity, the permeability and the tortuosity factor, and these porous material members are arranged along the fuel electrode in the order of the value of the porosity, the permeability or the tortuosity factor such that, the farther from the fuel supply port, the higher value of at least one of the porosity and the permeability of the porous material member in contact with the fuel electrode or the lower value of the tortuosity factor of the porous material member in contact with the fuel electrode.
8. The fuel cell according to claim 1, wherein the porous material layer includes a plurality of porous material members, and the contact area of at least one of the porous material members with the adjacent porous material member is increased with increase in the distance of a site of the porous material layer from the fuel supply port.
9. The fuel cell according to claim 1, wherein the porous material layer includes a plurality of porous material members and at least one shielding member, and the shielding member is arranged between the porous material members such that the area of the surface of at least one of the porous material members on the side of the fuel electrode is gradually increased with increase in the distance from the fuel supply port.
10. The fuel cell according to claim 1, wherein the porous material layer includes a plurality of porous material members and at least one shielding member, and the porous material members are inserted into through-holes open in the shielding member such that the open area per unit area of the porous material layer is increased with increase in the distance of a site of the shielding member from the fuel supply port.
11. The fuel cell according to claim 1, wherein the porous material layer includes a plurality of porous material members and a plurality of shielding members, and the shielding members are inserted into through-holes open in the porous material member such that the open area per unit area of the porous material layer is decreased with increase in the distance of a site of the porous material member from the fuel supply port.
12. The fuel cell according to claim 1, wherein the porous material layer is compressed at least partially.
13. The fuel cell according to claim 1, wherein the porous material layer includes a porous material member that is compressed such that the compression ratio is decreased with increase in the distance from the fuel supply port.
14. The fuel cell according to claim 1, wherein the porous material layer includes a porous material member having a tortuosity factor of 1.
15. A fuel cell, comprising:
a fuel electrode;
an oxidant electrode;
a fuel supply port; and
first and second porous material layers for transferring a liquid fuel from the fuel supply port to the fuel electrode;
wherein:
the first porous material layer has different values of at least one of a porosity, a permeability and a tortuosity factor depending on the distance of a site of the first porous material layer from at least one of the fuel supply port and the fuel electrode; and
the second porous material layer is formed of a single porous material member.
16. The fuel cell according to claim 15, wherein the first porous material layer is arranged in contact with the fuel electrode.
17. The fuel cell according to claim 15, wherein the first porous material layer includes a plurality of porous material members differing from each other in at least one of the porosity, the permeability and the tortuosity factor, and these porous material members are arranged along the fuel electrode in the order of the value of the porosity, the permeability or the tortuosity factor such that, the farther from the fuel supply port, the higher value of at least one of the porosity and the permeability of the porous material member in contact with the fuel electrode or the lower value of the tortuosity factor of the porous material member in contact with the fuel electrode.
18. The fuel cell according to claim 15, wherein the first porous material layer includes a laminate prepared by stacking a first porous material member having the thickness gradually increased with increase in the distance from the fuel supply port, and a second porous material member smaller than the than the first porous material member in at least one of the porosity and the permeability, and having the thickness gradually decreased with increase in the distance of a site of the second porous material member from the fuel supply port.
19. The fuel cell according to claim 15, wherein the first material layer includes a shielding member, porous material members inserted into through-holes open in the shielding member such that the open area per unit area of the first porous material layer is increased with increase in the distance from the fuel supply port, and a compressed porous material member that is compressed such that the compression ratio is decreased with increase in the distance from the fuel supply port.
20. A fuel cell, comprising:
a fuel electrode;
an oxidant electrode;
a fuel supply port; and
first and second porous material layers for transferring a liquid fuel from the fuel supply port to the fuel electrode;
wherein:
the first porous material layer is formed of a single porous material member; and
the second porous material layer includes a plurality of porous material members, and the contact area of at least one of the porous material members with the first porous material layer is increased with increase in the distance of a site of the second porous material layer from the fuel supply port.