Organic molecular memory

Abstract

To provide an organic molecular memory that can achieve large capacity.SOLUTION: An organic molecular memory according to an embodiment includes a first electrode, a second electrode, an organic molecular layer provided between the first electrode and the second electrode, extending in a first direction from the first electrode toward the second electrode, and including a first molecule and a second molecule provided between the first molecule and the second electrode, and a third electrode facing the second molecule. The first molecule and the second molecule include a metal complex or a fullerene derivative.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] FIELD OF THE INVENTION Embodiments of the present invention relate to organic molecular memories. [Background technology]

[0002] To achieve a larger capacity of nonvolatile memories, for example, miniaturization of memory cells and three-dimensional structuring of memory cell arrays are being promoted, and it is desired to realize a further increase in the capacity of nonvolatile memories. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-81627 Summary of the Invention [Problem to be solved by the invention]

[0004] One embodiment of the present invention provides an organic molecular memory that can achieve large capacity. [Means for solving the problem]

[0005] The organic molecular memory of the embodiment comprises a first electrode, a second electrode, an organic molecular layer disposed between the first electrode and the second electrode, extending in a first direction from the first electrode toward the second electrode, and including a first molecule and a second molecule disposed between the first molecule and the second electrode, and a third electrode facing the second molecule, wherein the first molecule and the second molecule include a metal complex or a fullerene derivative. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a block diagram of an organic molecular memory according to a first embodiment. [Figure 2] FIG. 2 is an equivalent circuit diagram of a memory cell array of the organic molecular memory according to the first embodiment. [Figure 3]FIG. 1 is a schematic cross-sectional view of an organic molecular memory according to a first embodiment. [Figure 4] FIG. 2 is a diagram showing an example of an organic molecule according to the first embodiment. [Figure 5] FIG. 2 is a diagram showing an example of an organic molecule according to the first embodiment. [Figure 6] FIG. 2 is a diagram showing an example of an organic molecule according to the first embodiment. [Figure 7] FIG. 2 is a diagram showing an example of an organic molecule according to the first embodiment. [Figure 8] FIG. 2 is a diagram showing an example of an organic molecule according to the first embodiment. [Figure 9] FIG. 2 is a diagram showing an example of an organic molecule according to the first embodiment. [Figure 10] FIG. 2 is a diagram showing an example of an organic molecule according to the first embodiment. [Figure 11] FIG. 1 is an explanatory diagram of an organic molecule according to a first embodiment. [Figure 12] FIG. 2 is a diagram showing an example of an organic molecule according to the first embodiment. [Figure 13] FIG. 2 is a diagram showing an example of an organic molecule according to the first embodiment. [Figure 14] FIG. 2 is a diagram showing an example of an organic molecule according to the first embodiment. [Figure 15] FIG. 2 is a diagram showing an example of an organic molecule according to the first embodiment. [Figure 16] FIG. 2 is a diagram showing an example of an organic molecule according to the first embodiment. [Figure 17] FIG. 1 is an explanatory diagram of an organic molecule according to a first embodiment. [Figure 18] FIG. 2 is an explanatory diagram of the operation of the organic molecular memory according to the first embodiment. [Figure 19] FIG. 2 is an explanatory diagram of the operation of the organic molecular memory according to the first embodiment. [Figure 20] FIG. 2 is an explanatory diagram of the operation of the organic molecular memory according to the first embodiment. [Figure 21] FIG. 2 is an explanatory diagram of the operation of the organic molecular memory according to the first embodiment. [Figure 22] FIG. 2 is an explanatory diagram of the operation of the organic molecular memory according to the first embodiment. [Figure 23] FIG. 2 is an explanatory diagram of the operation of the organic molecular memory according to the first embodiment. [Figure 24]FIG. 2 is an explanatory diagram of the operation of the organic molecular memory according to the first embodiment. [Figure 25] FIG. 2 is an explanatory diagram of the operation of the organic molecular memory according to the first embodiment. [Figure 26] FIG. 2 is an explanatory diagram of the operation of the organic molecular memory according to the first embodiment. [Figure 27] FIG. 2 is an explanatory diagram of the operation of the organic molecular memory according to the first embodiment. [Figure 28] FIG. 2 is an explanatory diagram of the operation of the organic molecular memory according to the first embodiment. [Figure 29] FIG. 2 is an explanatory diagram of the operation of the organic molecular memory according to the first embodiment. [Figure 30] FIG. 2 is an explanatory diagram of the operation of the organic molecular memory according to the first embodiment. [Figure 31] FIG. 4 is a schematic cross-sectional view of an organic molecular memory according to a modified example of the first embodiment. [Figure 32] FIG. 10 is an equivalent circuit diagram of a memory cell array of the organic molecular memory according to the second embodiment. [Figure 33] FIG. 10 is a schematic cross-sectional view of an organic molecular memory according to a second embodiment. [Figure 34] FIG. 10 is an explanatory diagram of the operation of the organic molecular memory according to the second embodiment. [Figure 35] FIG. 10 is an explanatory diagram of the operation of the organic molecular memory according to the second embodiment. [Figure 36] FIG. 10 is an explanatory diagram of the operation of the organic molecular memory according to the second embodiment. [Figure 37] FIG. 10 is an explanatory diagram of the operation of the organic molecular memory according to the second embodiment. [Figure 38] FIG. 10 is an explanatory diagram of the operation of the organic molecular memory according to the second embodiment. [Figure 39] FIG. 10 is an explanatory diagram of the operation of the organic molecular memory according to the second embodiment. [Figure 40] FIG. 10 is an explanatory diagram of the operation of the organic molecular memory according to the second embodiment. [Figure 41] FIG. 10 is an explanatory diagram of the operation of the organic molecular memory according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, embodiments will be described with reference to the drawings. In the following description, the same or similar components will be denoted by the same reference numerals, and the description of components that have already been described will be omitted as appropriate.

[0008] To identify the components constituting the organic molecular memory of the embodiment, for example, secondary ion mass spectroscopy (SIMS), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction analysis (XRD), electron beam diffraction analysis (EBD), X-ray photoelectron spectroscopy (XPS), synchrotron radiation X-ray absorption fine structure analysis (XAFS), liquid chromatography, gas chromatography, or ion chromatography can be used.

[0009] Furthermore, for example, a transmission electron microscope (TEM) can be used to measure the thickness of the members constituting the organic molecular memory of the embodiment, the distance between the members, and the like.

[0010] Furthermore, the molecular structure of an organic molecule can be identified using, for example, an atomic force microscope (AFM) or a scanning tunneling microscope (STM).

[0011] In this specification, the term "chemical bond" refers to any of covalent bonds, ionic bonds, and metallic bonds, and excludes hydrogen bonds and bonds based on van der Waals forces.

[0012] (First embodiment) The organic molecular memory of the first embodiment includes a first electrode, a second electrode, an organic molecular layer provided between the first electrode and the second electrode, extending in a first direction from the first electrode toward the second electrode, and including a first molecule and a second molecule provided between the first molecule and the second electrode, and a third electrode facing the second molecule. The first molecule and the second molecule include a metal complex or a fullerene derivative.

[0013] The organic molecular memory of the first embodiment is a nonvolatile organic molecular memory 100 in which memory cells are arranged three-dimensionally. In the organic molecular memory 100, the memory cells store data using the electric charges in the organic molecules. The organic molecular memory 100 operates as a shift register.

[0014] 1 is a block diagram of an organic molecular memory according to a first embodiment. As shown in FIG. 1, the organic molecular memory 100 includes a memory cell array 101, a write control circuit 102, a read control circuit 103, a shift control circuit 104, a sense amplifier circuit 105, and a central control circuit 106. The write control circuit 102 is an example of a first control circuit. The shift control circuit 104 is an example of a second control circuit.

[0015] FIG. 2 is an equivalent circuit diagram of a memory cell array of the organic molecular memory of the first embodiment.

[0016] As shown in FIG. 2, the memory cell array 101 includes a first memory string MS1, a second memory string MS2, a third memory string MS3, a fourth memory string MS4, a source plate SP, a lower select gate line SBG, an upper select gate line STG, a write line WL, a read line RL, a first bit line BL1, and a second bit line BL2.

[0017] The first bit line BL1 is an example of a first wiring, and the second bit line BL2 is an example of a second wiring.

[0018] Hereinafter, the first memory string MS1, the second memory string MS2, the third memory string MS3, and the fourth memory string MS4 may be individually or collectively referred to as memory strings MS. Also, the first bit line BL1 and the second bit line BL2 may be individually or collectively referred to as bit lines BL.

[0019] Each of the first memory string MS1, the second memory string MS2, the third memory string MS3, and the fourth memory string MS4 includes an organic molecular layer 10, a lower electrode 12, an upper electrode 14, a read electrode 16, a write electrode 18, a lower select gate transistor BST, and an upper select gate transistor TST.

[0020] The bottom electrode 12 is an example of a first electrode. The top electrode 14 is an example of a second electrode. The read electrode 16 is an example of a third electrode. The write electrode 18 is an example of a fourth electrode.

[0021] In the memory cell array 101, the direction from the lower electrode 12 to the upper electrode 14 is defined as a first direction. A direction intersecting the first direction is defined as a second direction. A direction intersecting the first and second directions is defined as a third direction. The second direction is, for example, perpendicular to the first direction. The third direction is, for example, perpendicular to the first and second directions.

[0022] As shown in FIG. 2, the first memory string MS1, the second memory string MS2, the third memory string MS3, and the fourth memory string MS4 extend in a first direction.

[0023] The first bit line BL1 and the second bit line BL2 extend in the second direction. The first memory string MS1 and the second memory string MS2 are provided between the first bit line BL1 and the source plate SP. The third memory string MS3 and the fourth memory string MS4 are provided between the second bit line BL2 and the source plate SP.

[0024] The first bit line BL1 is provided in a first direction of the first memory string MS1 and the second memory string MS2, and is electrically connected to the first memory string MS1 and the second memory string MS2.

[0025] The second bit line BL2 is arranged in a first direction of the third memory string MS3 and the fourth memory string MS4. The second bit line BL2 is electrically connected to the third memory string MS3 and the fourth memory string MS4. The second bit line BL2 is electrically isolated from the first bit line BL1.

[0026] The organic molecule layer 10 includes a plurality of organic molecules, each of which functions as a memory cell.

[0027] The lower select gate transistor BST is provided between the lower electrode 12 and the source plate SP. The lower select gate line SBG extends in the second direction.

[0028] The on / off state of the lower select gate transistor BST is controlled by the gate voltage applied to the lower select gate line SBG. The lower select gate transistor BST has the function of selecting a desired memory string MS from multiple memory strings MS. Note that the lower select gate transistor BST can be omitted.

[0029] The upper select gate transistor TST is provided between the upper electrode 14 and the first bit line BL1 or between the upper electrode 14 and the second bit line BL2. The upper select gate line STG extends in the third direction.

[0030] The on / off state of the upper select gate transistor TST is controlled by the gate voltage applied to the upper select gate line STG. The upper select gate transistor TST has the function of selecting a desired memory string MS from multiple memory strings MS.

[0031] By controlling the lower select gate transistor BST and the upper select gate transistor TST, it is possible to select one desired memory string MS.

[0032] The write line WL extends in the third direction and is connected to the write electrode 18. Data is written in the organic molecules facing the write electrode 18 by a write voltage applied to the write line WL.

[0033] For example, the write electrode 18 of the first memory string MS1 and the write electrode 18 of the third memory string MS3 are electrically connected by a write line WL. For example, the write electrode 18 of the second memory string MS2 and the write electrode 18 of the fourth memory string MS4 are electrically connected by a write line WL.

[0034] The readout line RL extends in the second direction. The readout line RL is connected to the readout electrode 16. By detecting the current flowing between the readout electrode 16 and the upper electrode 14, data on the organic molecules facing the readout electrode 16 is read out.

[0035] For example, the read electrode 16 of the first memory string MS1 and the read electrode 16 of the second memory string MS2 are electrically connected by a read line RL. For example, the read electrode 16 of the third memory string MS3 and the read electrode 16 of the fourth memory string MS4 are electrically connected by a read line RL.

[0036] The write control circuit 102 has a function of, for example, selecting a write line WL and controlling the voltage applied to the selected write line WL.

[0037] The read control circuit 103 has a function of, for example, selecting a read line RL and controlling a voltage applied to the selected read line RL.

[0038] The shift control circuit 104 has a function of controlling the shift register operation of the memory string MS. The shift control circuit 104 has a function of transferring data stored in the organic molecules OM in a first direction by applying a shift voltage between the lower electrode 12 and the upper electrode 14 of the memory string MS.

[0039] The sense amplifier circuit 105 has a function of detecting data stored in the organic molecules OM by amplifying the current flowing through the bit line BL or the voltage of the bit line BL.

[0040] The central control circuit 106 controls the operation of the organic molecular memory 100. The central control circuit 106 controls the write control circuit 102, the read control circuit 103, the shift control circuit 104, and the sense amplifier circuit 105.

[0041] The write control circuit 102, read control circuit 103, shift control circuit 104, sense amplifier circuit 105, and central control circuit 106 are configured, for example, by transistors and wiring layers formed on a semiconductor substrate (not shown).

[0042] Fig. 3 is a schematic cross-sectional view of the organic molecular memory of the first embodiment. Fig. 3 is a cross-sectional view of the memory cell array 101. Fig. 3 is a cross-sectional view parallel to the first direction and the third direction. Fig. 3 is a cross-section including the first memory string MS1.

[0043] The memory cell array 101 includes an organic molecular layer 10, a lower electrode 12, an upper electrode 14, a read electrode 16, a write electrode 18, a substrate insulating layer 20, an interlayer insulating layer 22, a source plate SP, a first bit line BL1, a lower select gate transistor BST, and an upper select gate transistor TST.

[0044] The bottom electrode 12 is an example of a first electrode. The top electrode 14 is an example of a second electrode. The read electrode 16 is an example of a third electrode. The write electrode 18 is an example of a fourth electrode.

[0045] The organic molecule layer 10 includes a first organic molecule OM1, a second organic molecule OM2, a third organic molecule OM3, a fourth organic molecule OM4, a fifth organic molecule OM5, a sixth organic molecule OM6, a seventh organic molecule OM7, and an eighth organic molecule OM8.

[0046] The first organic molecule OM1 is an example of a first molecule, and the eighth organic molecule OM8 is an example of a second molecule.

[0047] Hereinafter, the first organic molecule OM1, the second organic molecule OM2, the third organic molecule OM3, the fourth organic molecule OM4, the fifth organic molecule OM5, the sixth organic molecule OM6, the seventh organic molecule OM7, and the eighth organic molecule OM8 may be referred to individually or collectively as organic molecules OM.

[0048] The lower select gate transistor BST includes a first semiconductor layer 24. The upper select gate transistor TST includes a second semiconductor layer 26.

[0049] The substrate insulating layer 20 is, for example, an oxide. The substrate insulating layer 20 is, for example, a silicon oxide.

[0050] The source plate SP is provided on the substrate insulating layer 20. The source plate SP is a conductor. The source plate SP is, for example, a metal or a semiconductor. The source plate SP is, for example, tungsten.

[0051] The first semiconductor layer 24 is provided between the source plate SP and the lower electrode 12. The first semiconductor layer 24 is in contact with the source plate SP and the lower electrode 12, for example.

[0052] When the lower select gate transistor BST is in an on state, a channel is formed in the first semiconductor layer 24. The first semiconductor layer 24 is, for example, polycrystalline silicon.

[0053] A part of the source plate SP functions as a source / drain region of the lower select gate transistor BST. The lower electrode 12 functions as a source / drain region of the lower select gate transistor BST.

[0054] A part of the lower select gate line SBG functions as a gate electrode of the lower select gate transistor BST. A gate insulating film (not shown) is provided between the part of the lower select gate line SBG and the first semiconductor layer 24.

[0055] The lower select gate line SBG is a conductor, for example, a metal, for example, tungsten.

[0056] The lower electrode 12 is provided between the source plate SP and the organic molecular layer 10. The lower electrode 12 is provided between the first semiconductor layer 24 and the organic molecular layer 10. A dielectric layer is provided between the lower electrode 12 and the organic molecular layer 10. For example, a portion of an interlayer insulating layer 22 is provided between the lower electrode 12 and the organic molecular layer 10. The portion of the interlayer insulating layer 22 electrically isolates the lower electrode 12 and the organic molecular layer 10. The portion of the interlayer insulating layer 22 electrically isolates the lower electrode 12 and the first organic molecule OM1.

[0057] The lower electrode includes a first portion 12a. The first portion 12a faces the first organic molecule OM1 in a direction intersecting the first direction. The first portion 12a faces the first organic molecule OM1, for example, in a direction perpendicular to the first direction. The first portion 12a faces the first organic molecule OM1, for example, in a third direction.

[0058] A first organic molecule OM1 is provided between the first portion 12a and the write electrode 18. For example, in a direction intersecting the first direction, the first organic molecule OM1 is located between the first portion 12a and the write electrode 18. For example, in a direction perpendicular to the first direction, the first organic molecule OM1 is located between the first portion 12a and the write electrode 18. For example, in a third direction, the first organic molecule OM1 is located between the first portion 12a and the write electrode 18.

[0059] The distance between the first portion 12a and the first organic molecule OM1 is, for example, shorter than the length of the first organic molecule OM1 in the third direction. The distance between the first portion 12a and the first organic molecule OM1 is, for example, shorter than the arrangement pitch of the organic molecules OM in the first direction.

[0060] The lower electrode 12 is a conductor. The lower electrode 12 is, for example, a metal or a semiconductor. The lower electrode 12 is, for example, tungsten.

[0061] The organic molecular layer 10 is provided between the lower electrode 12 and the upper electrode 14. The organic molecular layer 10 extends in a first direction from the lower electrode 12 toward the upper electrode 14.

[0062] A first organic molecule OM1, a second organic molecule OM2, a third organic molecule OM3, a fourth organic molecule OM4, a fifth organic molecule OM5, a sixth organic molecule OM6, a seventh organic molecule OM7, and an eighth organic molecule OM8 are stacked in a first direction.

[0063] There are no chemical bonds between two organic molecules OM that are adjacent in a first direction. There are no covalent bonds, for example, between two organic molecules OM that are adjacent in a first direction.

[0064] For example, there is no chemical bond between a first organic molecule OM1 and a second organic molecule OM2 that are adjacent to each other in the first direction, or there is no covalent bond between the first organic molecule OM1 and the second organic molecule OM2.

[0065] The lengths of the organic molecules OM in the second and third directions are, for example, 5 nm to 20 nm, and the arrangement pitch of the organic molecules OM in the first direction is, for example, 1 nm to 5 nm.

[0066] The lengths of the organic molecule OM in the second and third directions are, for example, longer than the length of the organic molecule OM in the first direction.

[0067] The organic molecules OM include, for example, metal complexes or fullerene derivatives. The organic molecules OM include, for example, degenerate energy levels. The organic molecules OM include, for example, metal complexes or fullerene derivatives that include degenerate energy levels.

[0068] The organic molecule OM is, for example, a liquid crystal molecule. The organic molecule OM is, for example, a metal complex that is a liquid crystal molecule, or a fullerene derivative that is a liquid crystal molecule. A liquid crystal molecule is a molecule that can be in an intermediate state between a solid and a liquid.

[0069] The organic molecule OM includes, for example, a double-decker complex containing a side chain. A double-decker complex is a metal complex having a structure in which two planar molecules are stacked. The organic molecule OM includes, for example, two stacked phthalocyanine skeletons and one rare earth element selected from the group consisting of lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu). The organic molecule OM includes, for example, a rare earth element sandwiched between two phthalocyanine skeletons.

[0070] Fig. 4 is a diagram showing an example of an organic molecule according to the first embodiment. The organic molecule in Fig. 4 is a phthalocyanine double-decker complex. In the molecular structure in Fig. 4, "M" represents a rare earth element selected from the group consisting of lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

[0071] The phthalocyanine double-decker complex shown in Fig. 4 has two phthalocyanine skeletons stacked on top of each other, which are planar molecules. The phthalocyanine double-decker complex shown in Fig. 4 has two phthalocyanine skeletons stacked on top of each other. The plane formed by each phthalocyanine skeleton intersects with the first direction, for example, in the organic molecular layer 10. The plane formed by each phthalocyanine skeleton is approximately perpendicular to the first direction, for example, in the organic molecular layer 10. The plane formed by each phthalocyanine skeleton is provided along a plane perpendicular to the first direction, for example, in the organic molecular layer 10.

[0072] The phthalocyanine double-decker complex shown in Figure 4 includes a side chain. "R" in the molecular structure of Figure 4 represents the side chain. The side chain R is, for example, an alkyl chain having 3 to 18 carbon atoms. The side chain R includes, for example, an alkyl group, an orthoalkyl group, or a thioalkyl group.

[0073] The phthalocyanine double-decker complex shown in Figure 4 contains degenerate energy levels. Because two phthalocyanine skeletons are stacked, the number of states at the same energy level doubles.

[0074] The metal complex contained in the organic molecule OM is, for example, a metallocene derivative containing a side chain. The metallocene derivative contains, for example, one metal element selected from the group consisting of iron (Fe), copper (Cu), cobalt (Co), titanium (Ti), nickel (Ni), zinc (Zn), and chromium (Cr). The side chain contained in the metallocene derivative is, for example, an alkyl chain having 3 to 18 carbon atoms. The side chain R contains, for example, an alkyl group, an orthoalkyl group, or a thioalkyl group.

[0075] 5(a) and 5(b) are diagrams showing an example of an organic molecule according to the first embodiment. The organic molecules in FIGS. 5(a) and 5(b) are metallocene derivatives. The metallocene derivatives in FIGS. 5(a) and 5(b) contain iron (Fe) as a metal element. The metallocene derivatives in FIGS. 5(a) and 5(b) contain degenerate energy levels.

[0076] The metal complex contained in the organic molecule OM is, for example, a metalloporphyrin derivative containing a side chain. The metalloporphyrin derivative contains, for example, one metal element selected from the group consisting of iron (Fe), copper (Cu), cobalt (Co), titanium (Ti), nickel (Ni), zinc (Zn), and chromium (Cr). The side chain contained in the metalloporphyrin derivative is, for example, an alkyl chain having 3 to 18 carbon atoms. The side chain R contains, for example, an alkyl group, an orthoalkyl group, or a thioalkyl group.

[0077] Figures 6(a), 6(b), 7(a), 7(b), 8(a), and 8(b) are diagrams showing examples of organic molecules according to the first embodiment. The organic molecules shown in Figures 6(a), 6(b), 7(a), 7(b), 8(a), and 8(b) are metalloporphyrin derivatives. The "M" in the molecular structures shown in Figures 6(a), 6(b), 7(a), 7(b), 8(a), and 8(b) includes a metal element selected from the group consisting of iron (Fe), copper (Cu), cobalt (Co), titanium (Ti), nickel (Ni), zinc (Zn), and chromium (Cr). In the organic molecules shown in Figures 6(b), 8(a), and 8(b), chlorine (Cl) is bonded to the metal element.

[0078] In the molecular structures of Figures 6(a), 6(b), 7(a), 7(b), 8(a), and 8(b), "R" denotes a side chain. The side chain R is, for example, an alkyl chain having 3 to 18 carbon atoms. The side chain R includes, for example, an alkyl group, an orthoalkyl group, or a thioalkyl group.

[0079] Fig. 9 is a diagram showing an example of an organic molecule of the first embodiment. Fig. 9 is a metalloporphyrin derivative. Fig. 9 is a specific example of the metalloporphyrin derivative of Fig. 6(b). The metalloporphyrin derivative shown in Fig. 9 contains iron (Fe) as a metal element. In the metalloporphyrin derivative shown in Fig. 9, chlorine (Cl) is bonded to iron (Fe).

[0080] The metalloporphyrin derivatives shown in Figures 6(a), 6(b), 7(a), 7(b), 8(a), 8(b) and 9 contain degenerate energy levels.

[0081] The metal complex contained in the organic molecule OM is, for example, a metallophthalocyanine derivative containing a side chain. The metallophthalocyanine derivative contains, for example, one metal element selected from the group consisting of iron (Fe), copper (Cu), cobalt (Co), titanium (Ti), nickel (Ni), zinc (Zn), and chromium (Cr). The side chain contained in the metallophthalocyanine derivative is, for example, an alkyl chain having 3 to 18 carbon atoms. The side chain R contains, for example, an alkyl group, an orthoalkyl group, or a thioalkyl group.

[0082] 10(a) and 10(b) are diagrams showing an example of an organic molecule according to the first embodiment. The organic molecules shown in FIGS. 10(a) and 10(b) are metallophthalocyanine derivatives. "M" in the molecular structures shown in FIGS. 10(a) and 10(b) includes one metal element selected from the group consisting of iron (Fe), copper (Cu), cobalt (Co), titanium (Ti), nickel (Ni), zinc (Zn), and chromium (Cr).

[0083] In the molecular structures of Figures 10(a) and 10(b), "R" denotes a side chain. The side chain R is, for example, an alkyl chain having 3 to 18 carbon atoms. The side chain R includes, for example, an alkyl group, an orthoalkyl group, or a thioalkyl group.

[0084] The metalloporphyrin derivatives shown in Figures 10(a) and 10(b) contain degenerate energy levels.

[0085] When the organic molecules OM of the first embodiment are metal complexes, for example, each organic molecule OM has a cyclic structure in which the constituent atoms form a plane. For example, the plane formed by the constituent atoms of the cyclic structure of the organic molecule OM intersects with the first direction. For example, the planes formed by the constituent atoms of the cyclic structures of two adjacent organic molecules OM face each other in the first direction.

[0086] Furthermore, when the organic molecules OM of the first embodiment are metal complexes, each organic molecule OM contains a metal element. For example, the direction connecting the two metal elements contained in each of two adjacently arranged organic molecules OM is along the first direction. For example, the direction connecting the metal elements of two adjacently arranged organic molecules OM is the first direction.

[0087] Fig. 11 is an explanatory diagram of organic molecules according to the first embodiment. Fig. 11 is a diagram showing an example of the arrangement of a first organic molecule OM1 and a second organic molecule OM2. The first organic molecule OM1 and the second organic molecule OM2 are metalloporphyrin derivatives.

[0088] The first organic molecule OM1 has a first cyclic structure whose constituent atoms form a first plane P1. The first cyclic structure is a porphyrin skeleton. The second organic molecule OM2 has a second cyclic structure whose constituent atoms form a second plane P2. The second cyclic structure is a porphyrin skeleton.

[0089] The first plane P1 and the second plane P2 intersect with the first direction. The first plane P1 and the second plane P2 are, for example, substantially perpendicular to the first direction. The first plane P1 and the second plane P2 face each other in the first direction. In other words, the first plane P1 and the second plane P2 face each other in the stacking direction of the first organic molecule OM1 and the second organic molecule OM2.

[0090] The first organic molecule OM1 and the second organic molecule OM2 each have a metal element (M in FIG. 11). The direction connecting the two metal elements M of the first organic molecule OM1 and the second organic molecule OM2 arranged adjacent to each other is along the first direction. For example, the direction connecting the two metal elements M of the first organic molecule OM1 and the second organic molecule OM2 arranged adjacent to each other is the first direction.

[0091] For example, the organic molecules OM included in the organic molecular layer 10 satisfy the arrangement shown in Fig. 11 even if they are not adjacent organic molecules OM in the first direction. For example, the first organic molecule OM1 includes a first ring structure whose constituent atoms form a first face, and the eighth organic molecule OM8 includes a second ring structure whose constituent atoms form a second face, and the first face and the second face face each other in the first direction.

[0092] In this specification, the term "facing" includes the concept of having another element between the two facing elements. For example, one or more organic molecules may be present between the facing first and second surfaces. Also, for example, no other organic molecules may be present between the facing first and second surfaces.

[0093] The organic molecule OM is, for example, a fullerene derivative. The organic molecule OM is, for example, a fullerene derivative including a degenerate energy level. The organic molecule OM is, for example, a fullerene derivative including a side chain. The side chain included in the fullerene derivative includes, for example, an alkyl chain having 3 to 18 carbon atoms.

[0094] Figures 12(a), 12(b), 13(a), 13(b), 14(a), 14(b), 15(a), 15(b), and 16 are diagrams showing examples of organic molecules according to the first embodiment. The organic molecules in Figures 12(a), 12(b), 13(a), 13(b), 14(a), 14(b), 15(a), 15(b), and 16 are fullerene derivatives containing side chains.

[0095] The fullerene derivatives shown in Figures 12(a), 12(b), 13(a), 13(b), 14(a), 14(b), 15(a), 15(b), and 16 include degenerate energy levels.

[0096] FIG. 17 is an explanatory diagram of an organic molecule of the first embodiment. The organic molecule OM of the first embodiment includes degenerate energy levels. The organic molecule OM of the first embodiment includes degenerate orbitals. Therefore, the organic molecule OM of the first embodiment has multiple states at the same energy level. Therefore, the organic molecule OM of the first embodiment can hold three or more charges at the same energy level.

[0097] Figure 17 shows the electronic state of an organic molecule OM, which has two states at the same energy level. Figure 17 shows the lowest unoccupied molecular orbital (LUMO) of the organic molecule OM and the orbital one level above the LUMO (LUMO+1). In Figure 17, each black circle represents one electron.

[0098] As shown in Figure 17, two electrons can occupy each of the two states. Therefore, as shown in Figure 17, the number of electrons in the LUMO can be 0, 1, 2, 3, or 4. By assigning data 0 to the case where there are 0 electrons in the LUMO, data 1 to the case where there are 1 electron, data 2 to the case where there are 2 electrons, data 3 to the case where there are 3 electrons, and data 4 to the case where there are 4 electrons, the organic molecule OM can store five values.

[0099] Therefore, the organic molecular memory 100 including the organic molecule OM functions as a multi-value memory in which the same memory cell can store multiple values.

[0100] As shown in Figure 17, when an electron enters the LUMO, on-site Coulomb repulsion occurs, causing the energy level to shift upward. For example, when one electron enters, the LUMO shifts upward by Uev. For example, when another electron enters, the LUMO shifts upward by another Uev. Therefore, for example, there is a 4UeV difference in LUMO energy between data 0 and data 4. Note that in Figure 17, the energy difference between the LUMO and (LUMO+1) is Δ(delta)eV.

[0101] The upper electrode 14 is provided on the organic molecular layer 10. The upper electrode 14 is provided between the organic molecular layer 10 and the first bit line BL1. The organic molecular layer 10 is provided between the lower electrode 12 and the upper electrode 14.

[0102] The upper electrode 14 includes a second portion 14a. The second portion 14a faces the eighth organic molecule OM8 in a direction intersecting the first direction. The second portion 14a faces the eighth organic molecule OM8, for example, in a direction perpendicular to the first direction. The second portion 14a faces the eighth organic molecule OM8, for example, in a third direction.

[0103] An eighth organic molecule OM8 is provided between the second portion 14a and the readout electrode 16. For example, in a direction intersecting the first direction, the eighth organic molecule OM8 is located between the second portion 14a and the readout electrode 16. For example, in a direction perpendicular to the first direction, the eighth organic molecule OM8 is located between the second portion 14a and the readout electrode 16. For example, in a third direction, the eighth organic molecule OM8 is located between the second portion 14a and the readout electrode 16.

[0104] The distance between the second portion 14a and the eighth organic molecule OM8 is, for example, shorter than the length of the eighth organic molecule OM8 in the third direction. The distance between the second portion 14a and the eighth organic molecule OM8 is, for example, shorter than the arrangement pitch of the organic molecules OM in the first direction.

[0105] The upper electrode 14 is a conductor, such as a metal or a semiconductor, and is, for example, tungsten.

[0106] The write electrode 18 faces the first organic molecule OM1 in the third direction. The first organic molecule OM1 is provided between the write electrode 18 and the first portion 12a of the lower electrode in the third direction. The distance between the write electrode 18 and the first organic molecule OM1 is, for example, shorter than the length of the first organic molecule OM1 in the third direction. The distance between the write electrode 18 and the first organic molecule OM1 is, for example, shorter than the arrangement pitch of the organic molecules OM in the first direction.

[0107] The write electrode 18 has a function of injecting charges into the first organic molecules OM1. The write electrode 18 has a function of injecting electrons into the first organic molecules OM1, for example.

[0108] The write electrode 18 is electrically connected to a write line WL extending in a third direction, for example, in the depth direction of the paper. Although Fig. 3 illustrates a structure in which the write electrode 18 faces the first organic molecule OM1 in the third direction, it is also possible to employ a structure in which the write electrode 18 faces the first organic molecule OM1 in the second direction.

[0109] The write electrode 18 is a conductor. The write electrode 18 is, for example, a metal or a semiconductor. The write electrode 18 is, for example, tungsten.

[0110] The readout electrode 16 faces the eighth organic molecule OM8, for example, in a direction intersecting the first direction. The readout electrode 16 faces the eighth organic molecule OM8, for example, in a direction perpendicular to the first direction. The readout electrode 16 faces the eighth organic molecule OM8, for example, in a third direction. The distance between the readout electrode 16 and the eighth organic molecule OM8 is, for example, shorter than the length of the eighth organic molecule OM8 in the third direction. The distance between the readout electrode 16 and the eighth organic molecule OM8 is, for example, shorter than the arrangement pitch of the organic molecules OM in the first direction.

[0111] The readout electrode 16 has a function of passing a current through the eighth organic molecule OM8. A current is passed through the eighth organic molecule OM8 using the readout electrode 16 as one terminal and the upper electrode 14 as the other terminal.

[0112] The readout electrode 16 extends, for example, in the depth direction of the paper, that is, in the second direction.

[0113] The read electrode 16 is a conductor. The read electrode 16 is, for example, a metal or a semiconductor. The read electrode 16 is, for example, tungsten.

[0114] The upper select gate transistor TST includes a second semiconductor layer 26. The second semiconductor layer 26 is provided between the upper electrode 14 and the first bit line BL1. The second semiconductor layer 26 is in contact with, for example, the upper electrode 14 and the first bit line BL1.

[0115] When the upper select gate transistor TST is in an on state, a channel is formed in the second semiconductor layer 26. The second semiconductor layer 26 is, for example, polycrystalline silicon.

[0116] The upper electrode 14 functions as a source / drain region of the upper select gate transistor TST, and a part of the first bit line BL1 functions as a source / drain region of the upper select gate transistor TST.

[0117] A part of the upper select gate line STG functions as the gate electrode of the upper select gate transistor TST. A gate insulating film (not shown) is provided between the part of the upper select gate line STG and the second semiconductor layer 26.

[0118] The upper select gate line STG is a conductor, for example, a metal, for example, tungsten.

[0119] The first bit line BL1 is made of a conductor, such as a metal, such as tungsten.

[0120] The interlayer insulating layer 22 is, for example, an oxide. The interlayer insulating layer 22 is, for example, a silicon oxide.

[0121] Next, the operation of the organic molecular memory 100 will be described.

[0122] During write and read operations, the organic molecular memory 100 sequentially transfers data stored in a plurality of organic molecules OM stacked in the organic molecular layer 10 to adjacent organic molecules OM. During write and read operations, the organic molecular memory 100 performs a so-called shift register type operation.

[0123] Hereinafter, an example will be described in which the organic molecule OM can hold five values, data 0 to data 4, as shown in FIG.

[0124] 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, and 30 are explanatory diagrams of the operation of the organic molecular memory of the first embodiment.

[0125] 18 shows the initial state of operation of the organic molecular memory 100. In operation of the organic molecular memory 100, a first voltage V1 is applied to the lower electrode 12, a second voltage V2 is applied to the upper electrode 14, a third voltage V3 is applied to the read electrode 16, and a fourth voltage V4 is applied to the write electrode 18.

[0126] As shown in FIG. 18, the case where data stored in all organic molecules OM is data 0 is considered as the initial state of the operation of the organic molecular memory 100.

[0127] First, as shown in FIG. 19, consider the case where data is written to the first organic molecule OM1. When writing data to the first organic molecule OM1, the fourth voltage V4 is set to a voltage lower than the first voltage V1. For example, the first voltage V1 is set to 0 V, and the fourth voltage V4 is set to the write voltage Vwrite. The write voltage Vwrite is a negative voltage. The write voltage Vwrite is, for example, a voltage applied between the bottom electrode 12 and the write electrode 18.

[0128] Fig. 20 is a diagram illustrating the operation of writing data to the first organic molecule OM1. Fig. 20 is an explanatory diagram of writing data 1 to the first organic molecule OM1. That is, it is an explanatory diagram of the case where one electron is injected into the first organic molecule OM1. Fig. 20 is a diagram illustrating the time change of the electronic state of the first organic molecule OM1 and the Fermi level of the write electrode 18.

[0129] Before writing data 1, the data held by the first organic molecule OM1 is data 0 (time 0). Next, a first write voltage Vwrite1 is applied to the write electrode 18 (time 1). The first write voltage Vwrite1 is a negative voltage. By applying the first write voltage Vwrite1, the Fermi level of the write electrode 18 increases, and the Fermi level of the write electrode 18 and the (LUMO+1) of the first organic molecule OM1 are aligned. As the Fermi level of the write electrode 18 and the (LUMO+1) of the first organic molecule OM1 are aligned, one electron is injected from the write electrode 18 to the (LUMO+1) by tunneling.

[0130] When one electron is injected into (LUMO+1), on-site Coulomb repulsion occurs, and the LUMO and (LUMO+1) of the first organic molecule OM1 rise by U eV (time 2). The rise in (LUMO+1) creates an energy difference between (LUMO+1) and the Fermi level of the write electrode 18. Therefore, a second electron is not injected into (LUMO+1) from the write electrode 18.

[0131] Then, application of the first write voltage Vwrite1 to the write electrode 18 is stopped (time 3). After a certain time has elapsed, the electrons in (LUMO+1) move to the LUMO and stabilize. That is, the electrons in the excited state (LUMO+1) move to the LUMO and stabilize by dissipating energy.

[0132] Through the above process, data 1 is written to the first organic molecule OM1. After writing data 1 to the first organic molecule OM1, the LUMO and (LUMO+1) of the first organic molecule OM1 are in a state where their energies are higher by U eV than when data 0 is written.

[0133] Fig. 21 is a diagram illustrating the operation of writing data to the first organic molecule OM1. Fig. 21 is an explanatory diagram of the case where data 2 is written to the first organic molecule OM1. That is, it is an explanatory diagram of the case where two electrons are injected into the first organic molecule OM1. Fig. 21 is a diagram illustrating the change over time in the electronic state of the first organic molecule OM1 and the Fermi level of the write electrode 18.

[0134] Before writing data 2, the data held by the first organic molecule OM1 is data 0 (time 0). Next, a first write voltage Vwrite1 is applied to the write electrode 18 (time 1). The first write voltage Vwrite1 is a negative voltage. By applying the first write voltage Vwrite1, the Fermi level of the write electrode 18 increases, and the Fermi level of the write electrode 18 and the (LUMO+1) of the first organic molecule OM1 are aligned. As the Fermi level of the write electrode 18 and the (LUMO+1) of the first organic molecule OM1 are aligned, one electron is injected from the write electrode 18 to the (LUMO+1) by tunneling.

[0135] When one electron is injected into (LUMO+1), on-site Coulomb repulsion occurs, and the LUMO and (LUMO+1) of the first organic molecule OM1 rise by U eV (time 2). The rise in (LUMO+1) creates an energy difference with the Fermi level of the write electrode 18. Therefore, a second electron is not injected into (LUMO+1) from the write electrode 18.

[0136] Next, a second write voltage Vwrite2 is applied to the write electrode 18 (time 3). The second write voltage Vwrite2 is a negative voltage. The second write voltage Vwrite2 is a voltage different from the first write voltage Vwrtie. The second write voltage Vwrite2 is a voltage with an absolute value greater than that of the first write voltage Vwrtie.

[0137] Applying the second write voltage Vwrite2 further increases the Fermi level of the write electrode 18, aligning it with the (LUMO+1) of the first organic molecule OM1. The alignment of the Fermi level of the write electrode 18 with the (LUMO+1) of the first organic molecule OM1 allows a second electron to be injected from the write electrode 18 into the (LUMO+1) by tunneling.

[0138] When the second electron is injected into (LUMO+1), on-site Coulomb repulsion occurs, and the LUMO and (LUMO+1) of the first organic molecule OM1 rise by another U eV (time 4). The rise in (LUMO+1) creates an energy difference between (LUMO+1) and the Fermi level of the write electrode 18. Therefore, the third electron is not injected into (LUMO+1) from the write electrode 18.

[0139] Thereafter, the application of the second write voltage Vwrite2 to the write electrode 18 is stopped (time 5). After a certain period of time has elapsed, the electron in (LUMO+1) moves to the LUMO and stabilizes. Through the above process, data 2 is written to the first organic molecule OM1. After writing data 2 to the first organic molecule OM1, the LUMO and (LUMO+1) of the first organic molecule OM1 are in a state where their energies are 2 UeV higher than when data 0 was written.

[0140] As described above, when writing data 1 to the organic molecule OM, it is necessary to apply a first write voltage Vwrite1 to the organic molecule OM. When writing data 2 to the organic molecule OM, it is necessary to apply the first write voltage Vwrite1 to the organic molecule OM, and then apply a second write voltage Vwrite2, which has an absolute value greater than that of the first write voltage Vwrite1, to the organic molecule OM.

[0141] 22 is an explanatory diagram of the writing operation to the organic molecule OM. The horizontal axis of Fig. 22 represents time, and the vertical axis represents the magnitude of the writing voltage. The vertical axis represents the writing voltage in absolute value.

[0142] As shown in FIG. 22, when writing data 1 to the organic molecule OM, a first write voltage Vwrite1 is applied to the organic molecule OM. When writing data 2 to the organic molecule OM, the first write voltage Vwrite1 is applied to the organic molecule OM, and then a second write voltage Vwrite2 having an absolute value greater than that of the first write voltage Vwrite1 is applied. When writing data 3 to the organic molecule OM, the first write voltage Vwrite1 and the second write voltage Vwrite2 are applied to the organic molecule OM, and then a third write voltage Vwrite3 having an absolute value greater than that of the second write voltage Vwrite2 is applied. When writing data 4 to the organic molecule OM, the first write voltage Vwrite1, the second write voltage Vwrite2, and the third write voltage Vwrite3 are applied to the organic molecule OM, and then a fourth write voltage Vwrite4 having an absolute value greater than that of the third write voltage Vwrite3 is applied.

[0143] 22, in the organic molecular memory 100, when writing data to the organic molecule OM, a write voltage Vwrite of different magnitudes is used depending on the value of the data to be written. In the organic molecular memory 100, for example, when writing data to the organic molecule OM, a write voltage Vwrite of different magnitudes is applied between the lower electrode 12 and the write electrode 18 depending on the value of the data to be written.

[0144] As shown in FIG. 22, in the organic molecular memory 100, when writing data to the organic molecule OM, a plurality of write voltages Vwrite with different magnitudes are applied in stages between the lower electrode 12 and the write electrode 18.

[0145] The above-described operation of writing data to the organic molecule OM is controlled by, for example, a write control circuit 102.

[0146] If the injection of electrons from the write electrode 18 to (LUMO+1) is completed in an extremely short time, it may not be necessary to apply the write voltage Vwrite in a stepwise or staircase manner as shown in Fig. 22. For example, when writing data 4 to the organic molecule OM, it is also possible to increase the voltage applied to the organic molecule OM continuously from 0 V to a fourth write voltage Vwrite4.

[0147] When writing data 1 to the first organic molecule OM1, for example, the second voltage V2 is 0V and the third voltage V3 is 0V.

[0148] After writing data 2 to the first organic molecule OM1, the data in the organic molecule OM is transferred in the direction from the lower electrode 12 to the upper electrode 14, as shown in Fig. 23. Data 2 in the first organic molecule OM1 is transferred to the second organic molecule OM2.

[0149] When transferring data of the organic molecule OM, for example, the first voltage V1 is set to 0 V and the second voltage V2 is set to a shift voltage Vshift. The shift voltage Vshift is applied between the upper electrode 14 and the lower electrode 12. The shift voltage Vshift is a positive voltage.

[0150] Fig. 24 is a diagram illustrating the operation of transferring data from a first organic molecule OM1 to a second organic molecule OM2. Fig. 24 is an explanatory diagram of the case where data 2 is transferred from the first organic molecule OM1 to the second organic molecule OM2. That is, it is an explanatory diagram of the case where two electrons are transferred from the first organic molecule OM1 to the second organic molecule OM2. Fig. 24 is a diagram illustrating the change over time in the electronic state of the first organic molecule OM1 and the electronic state of the second organic molecule OM2.

[0151] Before transferring Data 2, the data held by the first organic molecule OM1 is Data 2. Furthermore, the data held by the second organic molecule OM2 is Data 0 (time 0).

[0152] Next, a first shift voltage Vshift1 is applied to the upper electrode 14. The first shift voltage Vshift1 is a positive voltage. A shift voltage Vshift1a, which is the capacitive division of the first shift voltage Vshift1, is applied between the second organic molecule OM2 and the first organic molecule OM1 (time 1).

[0153] By applying the first shift voltage Vshift1, the energy level of the second organic molecule OM2 is relatively lowered, and the LUMO of the first organic molecule OM1 is aligned with the (LUMO+1) of the second organic molecule OM2. As a result of the alignment of the LUMO of the first organic molecule OM1 with the (LUMO+1) of the second organic molecule OM2, one electron is injected by tunneling from the LUMO of the first organic molecule OM1 to the (LUMO+1) of the second organic molecule OM2.

[0154] When one electron is injected into the (LUMO+1) of the second organic molecule OM2, on-site Coulomb repulsion occurs, and the LUMO and (LUMO+1) of the second organic molecule OM2 rise by UeV. Meanwhile, when one electron is lost from the first organic molecule OM1, the on-site Coulomb repulsion decreases, and the LUMO and (LUMO+1) of the first organic molecule OM1 fall by UeV (time 2). An energy difference occurs between the LUMO of the first organic molecule OM1 and the (LUMO+1) of the second organic molecule OM2. Therefore, no second electron is injected from the first organic molecule OM1 to the second organic molecule OM2.

[0155] Next, a second shift voltage Vshift2 is applied to the upper electrode 14. The second shift voltage Vshift2 is a positive voltage. The second shift voltage Vshift2 is a voltage different from the first shift voltage Vshift1. The second shift voltage Vshift2 is a voltage having a larger absolute value than the first shift voltage Vshift1. A shift voltage Vshift2a, which is the capacitive division of the second shift voltage Vshift2, is applied between the second organic molecule OM2 and the first organic molecule OM1 (time 3).

[0156] By applying the second shift voltage Vshift2, the energy level of the second organic molecule OM2 is relatively lowered, and the LUMO of the first organic molecule OM1 is aligned with the (LUMO+1) of the second organic molecule OM2. As a result of the alignment of the LUMO of the first organic molecule OM1 with the (LUMO+1) of the second organic molecule OM2, a second electron is injected by tunneling from the LUMO of the first organic molecule OM1 to the (LUMO+1) of the second organic molecule OM2.

[0157] When a second electron is injected into the (LUMO+1) of the second organic molecule OM2, on-site Coulomb repulsion occurs, and the LUMO and (LUMO+1) of the second organic molecule OM2 rise by UeV. Meanwhile, when one electron is removed from the first organic molecule OM1, the on-site Coulomb repulsion decreases, and the LUMO and (LUMO+1) of the first organic molecule OM1 fall by UeV. An energy difference occurs between the LUMO of the first organic molecule OM1 and the (LUMO+1) of the second organic molecule OM2.

[0158] Then, the application of the second shift voltage Vshift2 to the upper electrode 14 is stopped (time 4). After a certain period of time has elapsed, the two electrons in (LUMO+1) of the second organic molecule OM2 are transferred to the LUMO of the second organic molecule OM2 and stabilized. Through the above process, data 2 is transferred from the first organic molecule OM1 to the second organic molecule OM2.

[0159] As described above, in order to transfer data 2 from a first organic molecule OM1 to an adjacent second organic molecule OM2, it is necessary to apply a first shift voltage Vshift1 and then apply a second shift voltage Vshift2 having an absolute value greater than that of the first shift voltage Vshift1.

[0160] Figure 25 is an explanatory diagram of the data shift operation of the organic molecule OM. The horizontal axis of Figure 25 represents time, and the vertical axis represents the magnitude of the shift voltage. The vertical axis represents the shift voltage in absolute value.

[0161] 25, when transferring data of the organic molecules OM, for example, a plurality of shift voltages with different magnitudes are applied in stages between the lower electrode 12 and the upper electrode 14. For example, as shown in Fig. 25, a first shift voltage Vshift1, a second shift voltage Vshift2, a third shift voltage Vshift3, a fourth shift voltage Vshift4, a fifth shift voltage Vshift5, a sixth shift voltage Vshift6, a seventh shift voltage Vshift7, an eighth shift voltage Vshift8, and a ninth shift voltage Vshift9 are applied in stages.

[0162] If the energy difference between LUMO and (LUMO+1) is Δ(delta) eV and the energy shift caused by the on-site Coulomb repulsion of one electron is Uev, for example, the first shift voltage Vshift1 is the voltage applied between adjacent organic molecules OM corresponding to (Δ-4U) eV, the second shift voltage Vshift2 is the voltage applied between adjacent organic molecules OM corresponding to (Δ-3U) eV, the third shift voltage Vshift3 is the voltage applied between adjacent organic molecules OM corresponding to (Δ-2U) eV, and the fourth shift voltage Vshift4 is the voltage applied between adjacent organic molecules OM corresponding to (Δ The fifth shift voltage Vshift5 is a voltage applied between adjacent organic molecules OM corresponding to ΔeV, the sixth shift voltage Vshift6 is a voltage applied between adjacent organic molecules OM corresponding to (Δ+U) eV, the seventh shift voltage Vshift7 is a voltage applied between adjacent organic molecules OM corresponding to (Δ+2U) eV, the eighth shift voltage Vshift8 is a voltage applied between adjacent organic molecules OM corresponding to (Δ+3U) eV, and the ninth shift voltage Vshift9 is a voltage applied between adjacent organic molecules OM corresponding to (Δ+4U) eV.

[0163] That is, when transferring data, shift voltages Vshift corresponding to all energy differences that can occur between the LUMO and (LUMO+1) of adjacent organic molecules OM are applied in stages, from shift voltages Vshift with smaller absolute values ​​to shift voltages Vshift with larger absolute values. By the shift operation, all electrons held in all organic molecules OM contained in the organic molecular layer 10 can be transferred to adjacent organic molecules OM.

[0164] The shift operation of the data of the organic molecules OM described above is controlled by, for example, the shift control circuit 104.

[0165] If the injection of electrons from the LUMO of one organic molecule OM to the (LUMO+1) of the adjacent organic molecule OM is completed in an extremely short time, it may not be necessary to apply the shift voltage Vshift in a stepwise or staircase manner as shown in Fig. 25. For example, it is also possible to increase the shift voltage Vshift continuously from 0 V to the ninth shift voltage Vshift9.

[0166] When transferring data of the organic molecule OM, for example, the read electrode 16 and the write electrode 18 are set to a floating potential. For convenience of explanation, the state in which the read electrode 16 and the write electrode 18 are set to a floating potential will be expressed below as the third voltage V3 and the fourth voltage V4 being a floating voltage Vfloating.

[0167] By repeatedly writing data to the first organic molecule OM1 and transferring the data from the organic molecule OM, data 0 to 4 are stored in all the organic molecules OM, as shown in Fig. 26. For example, by keeping the first voltage V1, the second voltage V2, the third voltage V3, and the fourth voltage V4 at a floating voltage Vfloating, the data stored in the organic molecule OM is retained. In other words, the organic molecular memory 100 functions as a nonvolatile memory that can retain data even when no power supply voltage is applied.

[0168] Next, as shown in FIG. 27, data of the eighth organic molecule OM8 is read. When reading data of the eighth organic molecule OM8, for example, the second voltage is set to 0 V and the third voltage is set to a read voltage Vread. The read voltage Vread is, for example, a positive voltage. The absolute value of the read voltage Vread is, for example, lower than the absolute value of the write voltage Vwrite.

[0169] A current flows from the readout electrode 16 through the eighth organic molecule OM8 to the second portion 14a. The magnitude of the current flowing through the eighth organic molecule OM8 varies depending on the data stored in the eighth organic molecule OM8. For example, when the data stored in the eighth organic molecule OM8 is data 3, a larger current flows than when the data stored in the eighth organic molecule OM8 is data 0, data 1, or data 2. This is because the conductance of the eighth organic molecule OM8 varies depending on the number of electrons held in the eighth organic molecule OM8.

[0170] The current flowing from the read electrode 16 to the upper electrode 14 flows to the first bit line BL1 through, for example, the upper select gate transistor TST that is turned on. Based on the current flowing to the first bit line BL1, data of the eighth organic molecule OM8 is read out.

[0171] The organic molecular memory 100 reads out data stored in the organic molecule OM by detecting the current flowing from the readout electrode 16 to the upper electrode 14. The current flowing from the readout electrode 16 to the upper electrode 14 is a tunneling current via the wave function of the organic molecule OM.

[0172] When reading out data of the eighth organic molecule OM8, for example, the first voltage V1 and the fourth voltage V4 are the floating voltage Vfloating.

[0173] After reading out the data of the eighth organic molecule OM8, the data of the organic molecule OM is transferred in the direction from the lower electrode 12 to the upper electrode 14, as shown in FIG. 28. When transferring the data of the organic molecule OM, for example, the first voltage V1 is set to 0 V, and the second voltage V2 is set to a shift voltage Vshift. The shift voltage Vshift is a positive voltage. The third voltage V3 and the fourth voltage V4 are floating voltages Vfloating.

[0174] For example, before transferring the data of the organic molecule OM, an operation of erasing the data of the eighth organic molecule OM8 may be performed. For example, when erasing the data of the eighth organic molecule OM8, the second voltage V2 and the third voltage V3 are set to positive voltages. By setting the second voltage V2 and the third voltage V3 to positive voltages, even if the data 3 is stored in the eighth organic molecule OM8, for example, it is possible to reset the data of the eighth organic molecule OM8 to data 0 by extracting electrons from the eighth organic molecule OM8.

[0175] Next, as shown in FIG. 29, the data of the eighth organic molecule OM8 is read. The data of the eighth organic molecule OM8 is the data stored in the seventh organic molecule OM7 before the data transfer. When reading the data of the eighth organic molecule OM8, for example, the second voltage is set to 0 V and the third voltage is set to a read voltage Vread. The first voltage V1 and the fourth voltage V4 are, for example, a floating voltage Vfloating.

[0176] By repeating the reading of the data from the eighth organic molecule OM8 and the transfer of the data from the organic molecules OM, it is possible to read out the data stored in all of the organic molecules OM in the organic molecular layer 10. After reading out the data stored in all of the organic molecules OM, the organic molecular layer 10 returns to its initial state as shown in FIG.

[0177] Next, the operation and effects of the organic molecular memory of the first embodiment will be described.

[0178] There is a demand for increasing the capacity and reducing the cost of nonvolatile memories. The organic molecular memory 100 of the first embodiment uses organic molecules for memory cells. By using minute organic molecules for memory cells, it becomes possible to miniaturize the memory cells. Furthermore, a plurality of organic molecules OM are arranged in one direction in a self-aligned manner to form a memory cell array 101 with a three-dimensional structure. Furthermore, by arranging the organic molecules OM in one direction and operating them in a shift register-type manner, for example, a control electrode for controlling each memory cell is not required.

[0179] The organic molecules OM of the organic molecular memory 100 have degenerate energy levels. Therefore, the organic molecules OM can hold three or more charges at the same energy level. Therefore, the organic molecular memory 100 including the organic molecules OM functions as a multi-valued memory in which one memory cell can store multiple values.

[0180] Furthermore, the organic molecular memory 100 performs a data write operation by utilizing the fluctuation of energy levels due to on-site Coulomb repulsion. In this write operation, electrons can be injected into the organic molecules OM individually and separately using different write voltages Vwrite. This prevents unintended electron injection into the organic molecules OM. This prevents erroneous data writing into the organic molecules OM. By preventing erroneous data writing, for example, a data verify operation becomes unnecessary.

[0181] With the above configuration, a multi-valued memory can be realized by the organic molecular memory 100 of the first embodiment. Therefore, it is possible to realize an organic molecular memory with a large capacity and low cost.

[0182] The organic molecules OM preferably contain alkyl chains with a carbon number of 3 or more as side chains, and more preferably alkyl chains with a carbon number of 4 or more. By containing alkyl chains as side chains, it becomes easier to align multiple organic molecules OM with each other in a self-aligned manner in a first direction.

[0183] In particular, when the organic molecule OM is a metal complex and includes a surface formed by atoms of a cyclic structure, it becomes easy to arrange the surfaces formed by the atoms of the cyclic structure of the organic molecule OM in a self-aligning manner so that they face each other in the first direction.

[0184] The organic molecules OM are preferably liquid crystal molecules, which makes it easy to align a plurality of organic molecules OM with each other in a self-aligned manner in the first direction.

[0185] In a direction intersecting the first direction, the organic molecules OM are preferably located between the first portion 12a of the lower electrode and the write electrode 18. In a direction perpendicular to the first direction, the organic molecules OM are preferably located between the first portion 12a and the write electrode 18. The above configuration stabilizes the operation of writing multi-valued data of the organic molecules OM.

[0186] In a direction intersecting the first direction, the organic molecule OM is preferably located between the second portion 14a of the upper electrode and the readout electrode 16. In a direction perpendicular to the first direction, the organic molecule OM is preferably located between the second portion 14a and the readout electrode 16. The above configuration stabilizes the readout operation of multi-valued data of the organic molecule OM.

[0187] (Variation) The organic molecular memory of the modified example differs from the organic molecular memory of the first embodiment in that it does not have the first portion of the first electrode and the second portion of the second electrode, i.e., the lower electrode does not have the first portion 12a and the upper electrode does not have the second portion 14a.

[0188] Fig. 31 is a schematic cross-sectional view of an organic molecular memory according to a modified example of the first embodiment, which corresponds to Fig. 3 of the first embodiment.

[0189] 31, the lower electrode 12 does not have the first portion 12a that the lower electrode 12 of the organic molecular memory 100 of the first embodiment had. Also, the upper electrode 14 does not have the second portion 14a that the upper electrode 14 of the organic molecular memory 100 of the first embodiment had.

[0190] The organic molecular memory of this modification can realize a nonvolatile memory with a large capacity and low cost, similar to the organic molecular memory 100 of the first embodiment.

[0191] (Second embodiment) The organic molecular memory of the second embodiment differs from the organic molecular memory of the first embodiment in that it does not have a fourth electrode. Hereinafter, some of the description overlapping with the first embodiment may be omitted.

[0192] The organic molecular memory of the second embodiment is a nonvolatile organic molecular memory 200 in which memory cells are arranged three-dimensionally. In the organic molecular memory 200, the memory cells store data using the electric charges in the organic molecules. The organic molecular memory 200 operates as a shift register.

[0193] FIG. 32 is an equivalent circuit diagram of a memory cell array of the organic molecular memory of the second embodiment.

[0194] As shown in FIG. 32, the memory cell array 201 includes a first memory string MS1, a second memory string MS2, a third memory string MS3, a fourth memory string MS4, a source plate SP, a select gate line SGL, a common line CL, a first bit line BL1, and a second bit line BL2.

[0195] The first bit line BL1 is an example of a first wiring, and the second bit line BL2 is an example of a second wiring.

[0196] Hereinafter, the first memory string MS1, the second memory string MS2, the third memory string MS3, and the fourth memory string MS4 may be individually or collectively referred to as memory strings MS. Also, the first bit line BL1 and the second bit line BL2 may be individually or collectively referred to as bit lines BL.

[0197] Each of the first memory string MS1, the second memory string MS2, the third memory string MS3, and the fourth memory string MS4 includes an organic molecular layer 10, a lower electrode 12, an upper electrode 14, a common electrode 17, and a select gate transistor SGT.

[0198] The lower electrode 12 is an example of a first electrode. The upper electrode 14 is an example of a second electrode. The common electrode 17 is an example of a third electrode. The select gate transistor SGT is an example of a first switching element.

[0199] In the memory cell array 201, the direction from the lower electrode 12 to the upper electrode 14 is defined as a first direction. A direction intersecting the first direction is defined as a second direction. A direction intersecting the first and second directions is defined as a third direction. The second direction is, for example, perpendicular to the first direction. The third direction is, for example, perpendicular to the first and second directions.

[0200] As shown in FIG. 32, the first memory string MS1, the second memory string MS2, the third memory string MS3, and the fourth memory string MS4 extend in a first direction.

[0201] The first bit line BL1 and the second bit line BL2 extend in the second direction. The first memory string MS1 and the second memory string MS2 are provided between the first bit line BL1 and the source plate SP. The third memory string MS3 and the fourth memory string MS4 are provided between the second bit line BL2 and the source plate SP.

[0202] The first bit line BL1 is arranged in a first direction between the first memory string MS1 and the second memory string MS2. The second bit line BL2 is arranged in a first direction between the third memory string MS3 and the fourth memory string MS4. The second bit line BL2 is electrically isolated from the first bit line BL1.

[0203] The organic molecule layer 10 includes a plurality of organic molecules, each of which functions as a memory cell.

[0204] The select gate transistor SGT is provided between the upper electrode 14 and the first bit line BL1 or between the upper electrode 14 and the second bit line BL2. The select gate line SGL extends in the third direction.

[0205] The select gate transistor SGT is controlled to be in an on state or an off state by a gate voltage applied to a select gate line SGL. The select gate transistor SGT has the function of selecting a desired memory string MS from among multiple memory strings MS.

[0206] The common line CL extends in the second direction. The common line CL is connected to a common electrode 17. A write voltage is applied to the common line CL to write data to the organic molecules facing the common electrode 17. Furthermore, by detecting the current flowing between the common electrode 17 and the upper electrode 14, the data of the organic molecules facing the common electrode 17 can be read out.

[0207] For example, the common electrode 17 of the first memory string MS1 and the common electrode 17 of the second memory string MS2 are electrically connected by a common line CL. For example, the common electrode 17 of the third memory string MS3 and the common electrode 17 of the fourth memory string MS4 are electrically connected by a common line CL.

[0208] Fig. 33 is a schematic cross-sectional view of the organic molecular memory of the second embodiment. Fig. 33 is a cross-sectional view of the memory cell array 201. Fig. 33 is a cross-sectional view parallel to the first direction and the third direction. Fig. 33 is a cross-section including the first memory string MS1.

[0209] The memory cell array 201 includes an organic molecular layer 10, a lower electrode 12, an upper electrode 14, a common electrode 17, a substrate insulating layer 20, an interlayer insulating layer 22, a source plate SP, a first bit line BL1, and a select gate transistor SGT.

[0210] The lower electrode 12 is an example of a first electrode. The upper electrode 14 is an example of a second electrode. The common electrode 17 is an example of a third electrode. The select gate transistor SGT is an example of a first switching element.

[0211] The organic molecule layer 10 includes a first organic molecule OM1, a second organic molecule OM2, a third organic molecule OM3, a fourth organic molecule OM4, a fifth organic molecule OM5, a sixth organic molecule OM6, a seventh organic molecule OM7, and an eighth organic molecule OM8.

[0212] The first organic molecule OM1 is an example of a first molecule, and the eighth organic molecule OM8 is an example of a second molecule.

[0213] Hereinafter, the first organic molecule OM1, the second organic molecule OM2, the third organic molecule OM3, the fourth organic molecule OM4, the fifth organic molecule OM5, the sixth organic molecule OM6, the seventh organic molecule OM7, and the eighth organic molecule OM8 may be referred to individually or collectively as organic molecules OM.

[0214] The substrate insulating layer 20 is, for example, an oxide. The substrate insulating layer 20 is, for example, a silicon oxide.

[0215] The source plate SP is provided on the substrate insulating layer 20. The source plate SP is a conductor. The source plate SP is, for example, a metal or a semiconductor. The source plate SP is, for example, tungsten.

[0216] The lower electrode 12 is provided between the source plate SP and the organic molecular layer 10 .

[0217] The lower electrode 12 is electrically connected to the source plate SP. The lower electrode 12 is in contact with the source plate SP, for example.

[0218] The lower electrode 12 is a conductor. The lower electrode 12 is, for example, a metal or a semiconductor. The lower electrode 12 is, for example, tungsten.

[0219] The organic molecular layer 10 is provided between the lower electrode 12 and the upper electrode 14. The organic molecular layer 10 extends in a first direction from the lower electrode 12 toward the upper electrode 14.

[0220] A first organic molecule OM1, a second organic molecule OM2, a third organic molecule OM3, a fourth organic molecule OM4, a fifth organic molecule OM5, a sixth organic molecule OM6, a seventh organic molecule OM7, and an eighth organic molecule OM8 are stacked in a first direction.

[0221] The upper electrode 14 is provided on the organic molecular layer 10. The upper electrode 14 is provided between the organic molecular layer 10 and the first bit line BL1.

[0222] The second portion 14a of the upper electrode faces the eighth organic molecule OM8 in the third direction. The eighth organic molecule OM8 is provided between the second portion 14a and the common electrode 17. The eighth organic molecule OM8 is located between the second portion 14a and the common electrode 17 in the third direction.

[0223] The upper electrode 14 is a conductor, such as a metal or a semiconductor, and is, for example, tungsten.

[0224] The common electrode 17 faces the eighth organic molecule OM8 in the third direction. The distance between the common electrode 17 and the eighth organic molecule OM8 is, for example, shorter than the length of the eighth organic molecule OM8 in the third direction. The distance between the common electrode 17 and the eighth organic molecule OM8 is, for example, shorter than the arrangement pitch of the organic molecules OM in the first direction.

[0225] The common electrode 17 has a function of injecting charges into the eighth organic molecule OM8. The common electrode 17 has a function of injecting electrons into the eighth organic molecule OM8, for example.

[0226] The common electrode 17 has a function of passing a current through the eighth organic molecule OM8. A current is passed through the eighth organic molecule OM8 with the common electrode 17 as one terminal and the upper electrode 14 as the other terminal.

[0227] The common electrode 17 is a conductor, such as a metal or a semiconductor, and is made of, for example, tungsten.

[0228] The select gate transistor SGT includes a semiconductor layer 25. The semiconductor layer 25 is provided between the upper electrode 14 and the first bit line BL1. The semiconductor layer 25 is in contact with, for example, the upper electrode 14 and the first bit line BL1.

[0229] When the select gate transistor SGT is in an on state, a channel is formed in the semiconductor layer 25. The semiconductor layer 25 is made of, for example, polycrystalline silicon.

[0230] The upper electrode 14 functions as the source / drain region of the select gate transistor SGT. A part of the first bit line BL1 functions as the source / drain region of the select gate transistor SGT.

[0231] A part of the select gate line SGL functions as a gate electrode of the select gate transistor SGT. A gate insulating film (not shown) is provided between the part of the select gate line SGL and the semiconductor layer 25.

[0232] The select gate line SGL is a conductor, such as a metal, such as tungsten.

[0233] The first bit line BL1 is made of a conductor, such as a metal, such as tungsten.

[0234] The interlayer insulating layer 22 is, for example, an oxide. The interlayer insulating layer 22 is, for example, a silicon oxide.

[0235] Next, the operation of the organic molecular memory 200 will be described.

[0236] During write and read operations, the organic molecular memory 200 sequentially transfers data stored in a plurality of organic molecules OM stacked in the organic molecular layer 10 to adjacent organic molecules OM. During write and read operations, the organic molecular memory 200 performs a so-called shift register type operation.

[0237] 34, 35, 36, 37, 38, 39, 40, and 41 are explanatory diagrams of the operation of the organic molecular memory of the second embodiment.

[0238] 34 shows the initial state of operation of the organic molecular memory 200. In operation of the organic molecular memory 200, a first voltage V1 is applied to the lower electrode 12, a second voltage V2 is applied to the upper electrode 14, and a third voltage V3 is applied to the common electrode 17.

[0239] As shown in FIG. 34, the case where the data stored in all organic molecules OM is data 0 is considered as the initial state of the operation of the organic molecular memory 200.

[0240] First, as shown in Figure 35, for example, data 2 is written to the eighth organic molecule OM8. When writing data 2 to the eighth organic molecule OM8, the third voltage V3 is set to a voltage lower than the second voltage V2. When writing data 2 to the eighth organic molecule OM8, for example, the second voltage V2 is set to 0V and the third voltage V3 is set to the write voltage Vwrite. The write voltage Vwrite is a negative voltage.

[0241] Electrons are injected from the common electrode 17 into the eighth organic molecule OM8, and data 2 is written in the eighth organic molecule OM8.

[0242] When writing data 2 to the eighth organic molecule OM8, for example, the first voltage V1 is 0V.

[0243] After writing data 2 to the eighth organic molecule OM8, the data of the organic molecule OM is transferred in the direction from the upper electrode 14 to the lower electrode 12, as shown in Fig. 36. When transferring the data of the organic molecule OM, for example, the second voltage V2 is set to 0 V, and the first voltage V1 is set to a shift voltage Vshift. The shift voltage Vshift is a positive voltage.

[0244] When transferring data of the organic molecules OM, for example, the common electrode 17 is set to a floating potential. For convenience of explanation, the state in which the common electrode 17 is set to a floating potential will be expressed below as the third voltage V3 being a floating voltage Vfloating.

[0245] By repeatedly writing data to the eighth organic molecule OM8 and transferring data from the organic molecules OM, data 0 to 4 are stored in all of the organic molecules OM, as shown in FIG. 37. For example, by keeping the first voltage V1, the second voltage V2, and the third voltage V3 at a floating voltage Vfloating, the data stored in the organic molecules OM is retained. In other words, the organic molecular memory 200 functions as a nonvolatile memory that can retain data even when no power supply voltage is applied.

[0246] Next, as shown in FIG. 38, the data of the eighth organic molecule OM8 is read. When reading the data of the eighth organic molecule OM8, for example, the second voltage is set to 0 V and the third voltage is set to a read voltage Vread. The read voltage Vread is a positive voltage. For example, the absolute value of the read voltage Vread is lower than the absolute value of the write voltage Vwrite.

[0247] A current flows from the common electrode 17 through the eighth organic molecule OM8 to the second portion 14a of the upper electrode. The magnitude of the current flowing through the eighth organic molecule OM8 varies depending on the data stored in the eighth organic molecule OM8. For example, when the data stored in the eighth organic molecule OM8 is data 4, a larger current flows than when the data stored in the eighth organic molecule OM8 is data 0, data 1, data 2, or data 3.

[0248] The current flowing from the common electrode 17 to the upper electrode 14 flows to the first bit line BL1, for example, through the select gate transistor SGT that is turned on. Based on the current flowing to the first bit line BL1, data of the eighth organic molecule OM8 is read out.

[0249] The organic molecular memory 200 detects the current flowing from the common electrode 17 to the upper electrode 14, thereby reading out the data stored in the organic molecules OM.

[0250] When reading out data of the eighth organic molecule OM8, for example, the first voltage V1 is a floating voltage Vfloating.

[0251] After reading out the data of the eighth organic molecule OM8, the data of the organic molecule OM is transferred in the direction from the lower electrode 12 to the upper electrode 14, as shown in FIG. 39. When transferring the data of the organic molecule OM, for example, the first voltage V1 is set to 0 V, and the second voltage V2 is set to a shift voltage Vshift. The shift voltage Vshift is a positive voltage. The third voltage V3 is a floating voltage Vfloating.

[0252] For example, before transferring the data of the organic molecule OM, an operation of erasing the data of the eighth organic molecule OM8 may be performed. For example, when erasing the data of the eighth organic molecule OM8, the second voltage V2 and the third voltage V3 are set to positive voltages. By setting the second voltage V2 and the third voltage V3 to positive voltages, for example, even if data 1 is stored in the eighth organic molecule OM8, electrons are extracted from the eighth organic molecule OM8, and the data of the eighth organic molecule OM8 can be reset to data 0.

[0253] Next, as shown in FIG. 40, the data of the eighth organic molecule OM8 is read. The data of the eighth organic molecule OM8 is the data stored in the seventh organic molecule OM7 before the data transfer. When reading the data of the eighth organic molecule OM8, for example, the second voltage is set to 0 V and the third voltage is set to a read voltage Vread. The first voltage V1 is, for example, a floating voltage Vfloating.

[0254] By repeating the reading of the data from the eighth organic molecule OM8 and the transfer of the data from the organic molecules OM, it is possible to read out the data stored in all of the organic molecules OM in the organic molecular layer 10. After reading out the data stored in all of the organic molecules OM, the organic molecular layer 10 returns to its initial state as shown in FIG.

[0255] As described above, according to the organic molecular memory of the second embodiment, similarly to the organic molecular memory of the first embodiment, it is possible to realize an organic molecular memory with a large capacity and low cost.

[0256] In the first and second embodiments, the case where the number of organic molecules OM in the organic molecular layer 10 is eight has been described as an example, but the number of organic molecules OM is not limited to 8. The number of organic molecules OM can be any number as long as it is two or more.

[0257] In the first and second embodiments, an example has been described in which the number of memory strings MS is four, but the number of memory strings MS is not limited to 4. The number of memory strings MS can be any number as long as it is one or more.

[0258] In the first and second embodiments, the case where the charge held by the organic molecule OM is an electron has been described as an example, but the charge held by the organic molecule OM may be a hole.

[0259] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments may be embodied in various other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. For example, components of one embodiment may be replaced or changed with components of another embodiment. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0260] 10 Organic molecular layer 12 Lower electrode (first electrode) 12a First Section 14 Upper electrode (second electrode) 14a Second Part 16 Readout electrode (third electrode) 17 Common electrode (third electrode) 18 Write electrode (fourth electrode) 100 Organic Molecular Memory 102 Write control circuit (first control circuit) 104 Shift control circuit (second control circuit) 200 Organic Molecular Memory BL1 First bit line (first wiring) BL2 Second bit line (second wiring) MS1 First memory string MS2 Second memory string MS3 Third memory string OM1 First organic molecule (first molecule) OM8 Eighth organic molecule (second molecule) P1 First side P2 Second side

Claims

1. a first electrode; a second electrode; and an organic molecule layer provided between the first electrode and the second electrode, extending in a first direction from the first electrode toward the second electrode, and including a first molecule and a second molecule provided between the first molecule and the second electrode; a third electrode facing the second molecule; Equipped with The organic molecular memory, wherein the first molecule and the second molecule include a metal complex or a fullerene derivative.

2. further comprising a fourth electrode; the first electrode further includes a first portion; the second electrode further includes a second portion; the first molecule is provided between the first portion and the fourth electrode in a direction intersecting the first direction; The organic molecular memory according to claim 1 , wherein the second molecule is provided between the second portion and the third electrode in a direction intersecting the first direction.

3. The organic molecular memory of claim 1 , wherein the first molecule and the second molecule comprise degenerate energy levels.

4. The organic molecular memory of claim 1 , wherein the first molecules and the second molecules are liquid crystal molecules.

5. the first molecule and the second molecule are metal complexes; the first molecule has a first ring structure whose constituent atoms form a first plane; the second molecule has a second ring structure whose constituent atoms form a second face; The organic molecular memory according to claim 1 , wherein the first surface and the second surface are opposed to each other in the first direction.

6. The organic molecular memory according to claim 1 , wherein the metal complex is a double-decker complex containing a side chain.

7. 7. The organic molecular memory according to claim 6, wherein the double-decker complex has two stacked phthalocyanine skeletons and contains one rare earth element selected from the group consisting of lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

8. The organic molecular memory according to claim 6 , wherein the side chain comprises an alkyl chain having three or more carbon atoms.

9. 2. The organic molecular memory according to claim 1, wherein the metal complex is a metallocene derivative having a side chain, a metalloporphyrin derivative having a side chain, or a metallophthalocyanine derivative having a side chain, and contains one metal element selected from the group consisting of iron (Fe), copper (Cu), cobalt (Co), titanium (Ti), nickel (Ni), zinc (Zn), and chromium (Cr).

10. The organic molecular memory according to claim 9 , wherein the side chain comprises an alkyl chain having three or more carbon atoms.

11. The organic molecular memory of claim 1 , wherein the fullerene derivative comprises a side chain.

12. The organic molecular memory according to claim 11 , wherein the side chain comprises an alkyl chain having three or more carbon atoms.

13. further comprising a first control circuit; When writing data to the first molecule, the first control circuit The organic molecular memory according to claim 2 , wherein a write voltage having a magnitude that varies depending on the value of the data is applied between the first electrode and the fourth electrode.

14. further comprising a first control circuit; When writing data to the first molecule, the first control circuit The organic molecular memory according to claim 2 , wherein a plurality of write voltages having different magnitudes are applied in stages between the first electrode and the fourth electrode.

15. further comprising a second control circuit; When transferring data from the first molecule to the second molecule, the second control circuit 3. The organic molecular memory according to claim 1, wherein a plurality of shift voltages having different magnitudes are applied in stages between the first electrode and the second electrode.

16. a first memory string extending in a first direction; a second memory string extending in the first direction; a third memory string extending in the first direction; a first wiring extending in a second direction intersecting the first direction and provided in the first direction of the first memory string and the second memory string; a second wiring extending in the second direction, electrically isolated from the first wiring, and provided in the first direction of the third memory string; Each of the first memory string, the second memory string, and the third memory string comprises: a first electrode; a second electrode provided between the first electrode and the first wiring or between the first electrode and the second wiring; an organic molecule layer provided between the first electrode and the second electrode, extending in the first direction, and including a first molecule and a second molecule provided between the first molecule and the second electrode; a third electrode facing the second molecule; The organic molecular memory, wherein the first molecule and the second molecule are a metal complex or a fullerene derivative.

17. each of the first memory string, the second memory string, and the third memory string further includes a fourth electrode; the first electrode further includes a first portion; the second electrode further includes a second portion; the first molecule is provided between a part of the first electrode and the fourth electrode in a direction intersecting the first direction; The organic molecular memory of claim 16 , wherein the second molecule is provided between a portion of the second electrode and the third electrode in a direction intersecting the first direction.

18. 17. The organic molecular memory of claim 16, wherein the first molecule and the second molecule comprise degenerate energy levels.

19. The organic molecular memory of claim 16 , wherein the first molecules and the second molecules are liquid crystal molecules.

20. the first molecule and the second molecule are metal complexes; the first molecule has a first ring structure whose constituent atoms form a first plane; the second molecule has a second ring structure whose constituent atoms form a second face; The organic molecular memory of claim 16 , wherein the first surface and the second surface are opposed to each other in the first direction.

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