JP3620041B2 - MEMORY DEVICE, ITS MANUFACTURING METHOD, AND ELECTRONIC DEVICE - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a memory device having a layer structure, and more particularly to a memory device in which memory layers having a simple matrix structure are stacked.
[0002]
[Prior art]
Memory device structures include a simple matrix structure in which memory cells are formed at the intersections of a pair of linear electrodes, and an active matrix structure in which a thin film transistor for selecting a memory cell is arranged for each memory cell. In a memory device having a simple matrix structure, a memory cell is selected by selecting an X direction linear electrode and a Y direction linear electrode corresponding to the memory cell.
[0003]
FIG. 15 is a diagram showing a specific configuration of a simple matrix structure. In this memory device, a pair of linear electrodes 11 and 13 that cross each other are disposed on a substrate 10 that serves as a support, and a memory layer 12 is provided between the linear electrodes 11 and 13. Hereinafter, the linear electrode 11 is referred to as an X direction linear electrode, and the linear electrode 13 is referred to as a Y direction linear electrode. In a memory device having a simple matrix structure, a memory cell is formed at an intersection where both linear electrodes 11 and 13 overlap in the stacking direction. Here, the stacking direction means a stacking direction in the manufacturing process, such as the substrate 10 / linear electrode 11 / memory layer 12 / linear electrode 13, and corresponds to the vertical direction in the drawing.
[0004]
FIG. 16 shows an equivalent circuit when the simple matrix structure is a 3 × 3 matrix. FIG. 16A is a memory cell layout diagram, and FIG. 16B is an equivalent circuit diagram. The memory cells 301 to 309 formed at the intersections of the X-direction linear electrode 11 and the Y-direction linear electrode 13 in FIG. 16A correspond to capacitors having the same reference numerals in FIG.
[0005]
FIG. 17 is a schematic plan view showing an arrangement of detection circuits and drive circuits 101 (hereinafter collectively referred to as “detection / drive circuits”) in a simple matrix structure. In a memory device having a simple matrix structure, in order to select a memory cell located at an intersection and perform read processing or write processing, current detection or voltage is independently applied to each X-direction and Y-direction linear electrode. It is necessary to have a configuration that can apply. Therefore, one detection / drive circuit 101 is connected and arranged for each X-direction and Y-direction linear electrode.
[0006]
Here, in order to increase the storage capacity, a stacked type memory device having a layer structure in which memory layers are stacked is known. FIG. 18 shows an example of a memory device having a simple matrix structure and a layer structure. 18A is a cross-sectional view of the XZ plane, and FIG. 18B is a cross-sectional view of the YZ plane.
[0007]
[Problems to be solved by the invention]
Since the conventional stacked type memory device has a configuration in which memory layers having a simple matrix structure are simply stacked, one detection / drive circuit 101 is also provided for each X-direction and Y-direction linear electrode for each layer. It was configured to be connected (see FIG. 18). In such a configuration, the number of detection / drive circuits 101 (number of layers × number of linear electrodes of each layer × 2) is required. Therefore, as the number of stacked layers increases, the number of detection / drive circuits and the like and the number of connection terminals with these circuits increase, which causes a complicated circuit configuration.
[0008]
In addition, the detection / drive circuit and the like (including the connection between the detection / drive circuit and the memory) are usually formed in a process separate from the process of forming the memory layer. Will be formed together. For this reason, as the number of stacked layers increases, the area of the circuit formation region occupied by the detection / drive circuit also increases, which is a problem in miniaturization.
[0009]
The present invention has been made in order to solve such a conventional problem, and an object thereof is to provide a compact stacked type memory device having a simple circuit configuration.
[0010]
[Means for Solving the Problems]
The memory device of the present invention is a memory device in which memory layers are stacked, and each memory layer has a simple matrix structure in which memory cells are formed at the intersections of the X direction linear electrodes and the Y direction linear electrodes. In addition, regarding a plurality of stacked memory layers, at least one of the linear electrodes in the X direction or the Y direction is short-circuited between the plurality of layers, and the other linear electrode can be applied with a voltage independently between the plurality of layers. It is configured. One linear electrode in the X direction or the Y direction may be short-circuited between the plurality of layers. According to such a configuration, the number of circuits and connection terminals connected to the linear electrodes can be reduced, and a memory device with a simple and compact circuit configuration can be realized.
[0011]
Further, a plurality of sets of the plurality of layers may be provided in a stacked memory layer. The plurality of layers may be formed by stacking one memory layer having a simple matrix structure by folding. Preferably, the number of the plurality of layers is the number of bits of 1 word in the memory device or an integer multiple thereof. According to such a configuration, it is possible to efficiently access the memory device in units of 1 word.
[0012]
The memory device of the present invention is characterized in that a single layer of a simple matrix structure is stacked in a spiral shape.
[0013]
In the memory device of the present invention, a ferroelectric layer or a charge transfer complex can be used for the memory layer.
[0014]
The memory device of the present invention can be used as a memory of an electronic device. The electronic device means a computer, a printer or other CPU, a memory, and a data input / output device.
[0015]
A method of manufacturing a memory device according to the present invention is a method of manufacturing a memory device in which memory layers are stacked, and has a simple matrix structure in which memory cells are formed at intersections of X-direction linear electrodes and Y-directional linear electrodes. A step of laminating layers, and a step of short-circuiting at least one linear electrode in the X direction or the Y direction between the plurality of layers with respect to a plurality of layers of the laminated memory layers.
[0016]
The step of short-circuiting may be configured such that one linear electrode in the X direction or the Y direction is short-circuited between the plurality of layers. Further, the short-circuiting step may be configured to be performed on a plurality of sets of the plurality of layers. Preferably, the number of the plurality of layers is configured to be the number of bits of 1 word in the memory device or an integer multiple thereof.
[0017]
A method of manufacturing a memory device according to the present invention is a method of manufacturing a memory device in which memory layers are stacked, and has a simple matrix structure in which memory cells are formed at intersections of X-direction linear electrodes and Y-directional linear electrodes. A step of forming a layer; and a step of laminating the formed simple matrix memory layer by folding. According to this configuration, the step of short-circuiting the linear electrode can be omitted.
[0018]
A method of manufacturing a memory device according to the present invention is a method of manufacturing a memory device in which memory layers are stacked, and has a simple matrix structure in which memory cells are formed at intersections of X-direction linear electrodes and Y-directional linear electrodes. The step of forming the layer and the memory layer having the simple matrix structure formed as described above are stacked in a spiral shape. According to this configuration, the step of short-circuiting the linear electrode can be omitted.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of a memory device and a manufacturing method thereof according to the present invention will be described with reference to the drawings.
(Example 1)
1 is a schematic perspective view of a memory device according to a first embodiment of the present invention, FIG. 2A is a schematic diagram of an XZ section, and FIG. 2B is a schematic diagram of a YZ section.
[0020]
As shown in FIGS. 1 and 2, the memory device 1 according to the first embodiment of the present invention has a configuration in which n layers of memory layers 100 are stacked. Each memory layer 100 has a simple matrix structure in which an X-direction linear electrode 11 and a Y-direction linear electrode 13 are arranged and a memory cell is formed at the intersection.
[0021]
Here, in this embodiment, n = 4, that is, four memory layers are stacked, but how many layers are stacked can be determined according to the design. In addition, the number of linear electrodes in each layer is determined according to the number of memory cells in one layer. However, in order to simplify the explanation, two X-directional linear electrodes and two Y-directional linear electrodes are shown in the figure. did.
[0022]
As shown in FIG. 2A, the X-direction linear electrode 11 is connected to a detection / drive circuit 101 independently for each layer. On the other hand, as shown in FIG. 2B, the Y-direction linear electrode 13 is short-circuited in the stacking direction, and the detection / drive circuit 101 is connected in common to each layer.
[0023]
In such a configuration, the X-direction linear electrode side requires (number of layers × number of linear electrodes in each layer) detection / drive circuits 101, but the Y-direction linear electrode side has (number of linear electrodes in each layer). Only one detection / drive circuit 101 is sufficient, and the detection / drive circuit 101 is constant regardless of an increase in the number of layers.
[0024]
In this embodiment, the linear electrodes are short-circuited with respect to the Y-directional linear electrodes. However, since the X-direction and the Y-direction are relative concepts, the X-directional linear electrodes are substituted for the Y-directional linear electrodes. It is good also as a structure which short-circuits about.
[0025]
In the memory device having such a configuration, the principle that a memory cell in an arbitrary layer can be selected and a voltage can be applied even if one of linear electrodes in the X direction or the Y direction is short-circuited will be described. Since the Y-direction linear electrode is short-circuited in the stacking direction, a voltage is simultaneously applied to the linear electrode at the same position in each layer. Therefore, a layer cannot be selected only by such Y-direction linear electrodes. However, with respect to the X-direction linear electrode, since a detection / drive circuit is connected to each layer, a voltage can be applied independently for each layer. Therefore, the layer can be selected depending on which layer of the X-direction linear electrode the voltage is applied to. For example, when it is desired to select the memory cell 200, a voltage may be applied to each linear electrode as shown in FIG. For example, when it is desired to select a memory cell 201 in a layer different from the memory cell 200, a voltage may be applied to each linear electrode as shown in FIG. In addition, the linear electrode shown with a thick line in a figure shows that the predetermined voltage is applied. As described above, any layer can be selected as long as the voltage can be applied independently for each layer in either the X direction or the Y direction. The selection of memory cells in the selected layer may be performed in the same manner as in a single layer memory device having a simple matrix structure.
[0026]
Next, the manufacturing process of the memory device of Example 1 will be described. In the manufacturing process, a memory layer forming process (1) to (4) for forming a memory layer having a simple matrix structure and a linear electrode in either the X direction or the Y direction are short-circuited between a plurality of layers with respect to the stacked memory layers And a linear electrode short-circuiting step (5). The memory layer forming step includes four steps of (1) X-direction linear electrode forming step, (2) dielectric layer forming step, (3) Y-direction linear electrode forming step, and (4) insulating layer forming step. Thus, the memory layer can be stacked by repeating these four steps as many as the number of layers to be stacked (eight layers in this embodiment).
(1) X-direction linear electrode forming step (FIG. 4A)
An electrode layer is formed on the substrate 10 (in the case of the second and subsequent layers, an insulating layer). The electrode layer is obtained by forming a platinum film by a direct current sputtering method, an electron beam evaporation method or the like. As a suitable electrode other than platinum, a noble metal electrode such as palladium, IrO ₂ , RuO ₂ , ReO ₃ There are conductive compounds such as
[0027]
After the electrode layer is formed, a resist (not shown) is applied, patterned linearly in the X direction, and dry etching is performed using this as a mask. By this process, a plurality of X-direction linear electrodes 11 are formed. In the figure, it is linear in the direction from the front to the back.
(2) Memory layer forming step (FIG. 4B)
A memory layer 12 is formed on the X-direction linear electrode 11. In this embodiment mode, a case where a film is formed by a sol-gel method will be described. The memory layer 12 can be used as long as it can be used as a capacitor. For example, in the present invention, a ferroelectric material can be used as the memory layer. Specifically, lead titanate (PbTiO ₃ ), Lead zirconate titanate (Pb (Zr, Ti) O) ₃ ), Lead zirconate (PbZrO) ₃ ), Lead lanthanum titanate ((Pb, La), TiO) ₃ ), Lead lanthanum zirconate titanate ((Pb, La) (Zr, Ti) O) ₃ ) Or lead magnesium niobate zirconium titanate (Pb (Zr, Ti) (Mg, Nb) O) ₃ ) Can be used as a ferroelectric memory. In addition, a charge transfer complex can be used as the memory layer. Specifically, an organometallic charge transfer complex using 7,7,8,8-tetracyanoquinodimethane (TCNQ) as a base and Cu as a donor can be preferably used. In addition, a dielectric material can be appropriately selected and used.
[0028]
A thin film as the memory layer can be formed by a sol-gel method. Hydrate complex of metal component hydroxide capable of forming a layer, that is, a sol is applied to the X-direction linear electrode 11 and the substrate 10, dried and degreased into a precursor, and this precursor is subjected to RTA treatment. Crystallize to obtain a thin film.
[0029]
Further, the memory layer can be formed not only by the sol-gel method described above but also by high-frequency sputtering, MOD (Metal Organic Decomposition Process), printing method, or the like. As for the sputtering film forming method, Japanese Patent Application Laid-Open No. 8-277195 and Japan Journal of Applied Physics Vol. 32 pp4122-4125 “Preparation and Characterization of Pb (Zr _x Ti _1-x ) O ₃ It is described in detail in documents such as “Thin Films by Reactive Suttering using an Alloy Target.” Further, the formation of a memory layer by a printing method is disclosed in detail in Japanese Patent Laid-Open No. 3-128681.
[0030]
After the memory layer is formed, a resist (not shown) is applied, and dry etching is performed using this as a mask so that the surface becomes smooth.
(3) Y-direction linear electrode forming step (FIG. 4C)
An electrode layer is formed on the memory layer 12. The electrode layer is obtained by forming a platinum film by a direct current sputtering method, an electron beam evaporation method or the like. As a suitable electrode other than platinum, a noble metal electrode such as palladium, IrO ₂ , RuO ₂ , ReO ₃ There are conductive compounds such as
[0031]
After the electrode layer is formed, a resist (not shown) is applied and patterned in a direction perpendicular to the X-direction linear electrode 11 (Y direction), and dry etching or the like is performed using this as a mask. Through this process, a plurality of Y-direction linear electrodes 13 are formed.
(4) Insulator layer forming step (FIG. 4D)
On the Y-direction linear electrode layer 13, an ordinary method such as PSG or SiO ₂ Or Si ₃ N ₄ Etc. is used to form the insulator layer 14 by atmospheric pressure CVD, plasma CVD, or the like. By forming the insulator layer 14, the insulator layer 14 enters between adjacent memory cells, and crosstalk is reduced.
(5) Linear electrode short-circuiting process (FIGS. 4E and 4F)
By repeating the steps (1) to (4), the through holes 20 are formed in the stacking direction, for example, by subjecting the stacked memory layers to drilling with a laser beam. Through-hole formation may be performed before lamination. The through hole 20 is formed so as to pass through each Y-direction linear electrode, for example, as shown in the plan view of FIG. Then, the connecting terminal 21 is formed by short-circuiting the Y-direction linear electrodes of the respective layers by plating a conductive material such as copper or nickel with respect to the formed through holes. The connection terminal 21 is connected to a corresponding detection / drive circuit (not shown in FIG. 4).
(X-direction linear electrode connection terminal forming step)
As for the X-direction linear electrodes, the connection terminals may be formed as follows in each memory layer formation process, as in the conventional stacked memory device.
[0032]
That is, when forming each memory layer, the X-direction linear electrode is extended outside the memory cell area 30 by a different length for each memory layer (shorter toward the lower layer and longer toward the upper layer). Then, the extension part 31 is formed (FIGS. 6A to 6D). Then, after the memory layer is formed, a through hole 32 is formed in the extended portion 31 of the memory layer at a position where it does not overlap with the extended portion 31 of the memory layer below the memory layer (see FIG. 6 (e)). Then, an independent connection terminal 21 is formed for each layer by plating a conductive material such as copper or nickel (FIG. 6F). Such a process is executed for each memory layer (FIG. 6G). The connection terminal 21 is connected to a corresponding detection / drive circuit (not shown in FIG. 6) similarly to the Y-direction linear electrode.
[0033]
By adopting a configuration in which the linear electrodes in either the X direction or the Y direction are short-circuited in this way, the number of connection terminals and the number of detection / drive circuits can be reduced compared to conventional memory devices. The configuration can be simplified. As a result, circuit reliability and yield can be improved. Further, since the detection / drive circuit is shared for the linear electrodes in the Y direction, the area (volume) occupied by these circuits can be reduced, and the memory device can be made compact.
(Example 2)
7 is a schematic perspective view of a memory device according to Embodiment 2 of the present invention, and FIG. 8 is a schematic diagram of a YZ cross section.
[0034]
As shown in FIGS. 7 and 8, the memory device 2 according to the second embodiment of the present invention includes n layers of memory layers 100 having a simple matrix structure (n = 8), and the X-direction linear electrode 11 is Similar to the first embodiment, the detection / drive circuit 101 is connected to each layer independently. However, as shown in FIG. 8, the Y-direction linear electrode 13 is detected in common for each group in a state where n memory layers are grouped by m layers and each group is short-circuited in the stacking direction. The second embodiment is different from the first embodiment in that the drive circuit 101 is connected.
[0035]
Here, in this embodiment, n = 8 and m = 4. However, how many layers are stacked and how many layers are grouped can be determined according to design. In addition, the number of linear electrodes in each layer is determined according to the number of memory cells in one layer. However, in order to simplify the explanation, two X-directional linear electrodes and two Y-directional linear electrodes are shown in the figure. did.
[0036]
In such a configuration, the X-direction linear electrode side requires (number of layers × number of linear electrodes in each layer) detection / drive circuits 101, whereas the Y-direction linear electrode side has (number of groups × linearity of each layer). The number of electrodes) is the number of detection / drive circuits 101.
[0037]
In this embodiment, the linear electrodes are short-circuited with respect to the Y-directional linear electrodes. However, since the X-direction and the Y-direction are relative concepts, the X-directional linear electrodes are substituted for the Y-directional linear electrodes. It is good also as a structure which short-circuits about.
[0038]
The manufacturing method of the memory device of Example 2 is the same as that of Example 1 with respect to the process of forming the memory layer and the process of forming the connection terminal of the X-direction linear electrode.
[0039]
However, in the process of forming each memory layer, the Y-direction linear electrode is also formed with an extended portion outside the memory cell area and a plurality of memory layers in which the linear electrode short-circuit process is grouped. Each point is different.
[0040]
In the Y-direction linear electrode forming step in the process of forming each memory layer, the Y-direction linear electrode is different in each group by a different length (shorter toward the lower layer and longer toward the upper layer). The extended portion 31 is formed by being pulled out from 30. (See Fig. 9 (a))
Then, in the linear electrode short-circuiting process, when the plurality of memory layers constituting the group are formed, the extension portion 31 of the group does not overlap with the extension portion 31 of the group lower than the group. A through hole is formed so as to pass through the position. Then, for example, by plating a conductive material such as copper or nickel, the Y-direction linear electrodes of each group are short-circuited through the through holes to form the connection terminals 21 (see FIG. 9B).
[0041]
Here, the number m of memory layers constituting the group is desirably the number of bits constituting one word in the memory device or an integer multiple thereof. For example, when 1 word is 8 bits, one group is composed of 8 layers. Hereinafter, the desirable reason will be described assuming that 1 word is 8 bits.
[0042]
Normally, access to a memory device is performed in units of 1 word (or an integer multiple thereof). If a memory cell is a binary memory cell (that is, 1 bit), 8 memory cells are required to configure 1 word, and the 8 memory cells are configured on the same memory layer. It is not preferable to end up. This is because, in a memory device having a simple matrix structure, only one memory cell can be accessed at the same time in the same memory layer. Therefore, if 1 word is composed of memory cells in the same memory layer, 1 word (that is, 8 memories) This is because the load on the detection / driving circuit increases because the cell) must be accessed simultaneously. Therefore, in the memory device of this embodiment, one word is composed of memory cells in different layers.
[0043]
Here, in the memory device of this embodiment, since the Y-direction linear electrodes are short-circuited in units of groups, voltage application to the Y-direction linear electrodes is performed in units of groups. For example, if the number of layers m of a group is 4, in order to access a 1 word memory, a voltage must be applied to the Y-direction linear electrodes of the two groups. For example, if the number of layers m of the group is 10, when the 1 word memory is accessed, the voltage is also applied to the Y-direction linear electrodes for two layers that do not need to be accessed. Therefore, by making the number of layers m of the group equal to the number of bits constituting 1 word, it is possible to efficiently apply a voltage only to the Y direction linear electrodes of the required memory layer. In addition, when p times the number of bits constituting one word (p is an integer), (p) word can be accessed simultaneously by applying a voltage to the Y-direction linear electrodes of one group. A device can be provided.
(Example 3)
10 is a schematic perspective view of a memory device according to Embodiment 3 of the present invention, and FIG. 11 is a schematic diagram of a YZ cross section. However, in order to make the drawing easier to see, the detection / drive circuit connected to the X-direction linear electrode is omitted in FIG.
[0044]
As shown in FIGS. 10 and 11, the memory device 3 according to the third embodiment of the present invention has a simple matrix structure of n layers of memory layers 100, and the X-direction linear electrode 11 is independently detected and layered. This is the same as the first embodiment in that the drive circuit 101 is connected.
[0045]
However, as shown in FIG. 11, the Y-direction linear electrode 13 is the same as the first embodiment in that the detection / drive circuit is connected in a short-circuited state in the stacking direction. This embodiment is different in that it is short-circuited on the same side surface of the device, but in this embodiment, it is configured to be alternately short-circuited on two opposite side surfaces of the memory device.
[0046]
Next, a manufacturing process of the memory device of Example 3 will be described. The manufacturing process includes a planar memory layer forming process for forming a planar memory layer having a simple matrix structure, and a folding process for stacking a plurality of memory layers by folding the planar memory layer in a predetermined direction.
[0047]
The planar memory layer forming step can be performed in the same manner as steps (1) to (4) of the first embodiment.
[0048]
In the folding step, the memory layer is laminated by folding the planar memory layer as shown in FIG. The memory device obtained as a result of this process has a configuration in which two opposing side surfaces are alternately short-circuited. After folding, the shape may be maintained by adhesion or the like, or may be fixed in a housing.
[0049]
Here, by forming the planar memory layer so that the length of the Y-direction linear electrode = (number of layers × the length of the X-directional linear electrode), the X direction of each layer in the stacked state The number of linear electrodes in the Y direction can be made the same.
[0050]
In this example, in addition to the same effects as in Example 1, by folding the planar memory layer, it is possible to realize a configuration in which the Y-direction linear electrodes are substantially short-circuited in the stacking direction. The step of performing can be omitted.
(Example 4)
FIG. 13 is a schematic perspective view of a memory device according to Embodiment 4 of the present invention, and FIG. 14 is a schematic diagram of a cross section in the radial direction.
[0051]
As shown in FIGS. 13 and 14, the memory device 4 according to the fourth embodiment of the present invention has a configuration in which memory layers having a simple matrix structure are spirally wound and stacked in the radial direction. Here, assuming that a layer rotated 360 degrees once is regarded as one layer, the X-direction linear electrode is connected to the detection / drive circuit 101 independently for each layer. The Y-direction linear electrode is connected to the detection / drive circuit 101 in common for each layer in a state where all layers are short-circuited (connected). In order to make the drawing easier to see, some of the X-direction linear electrodes and the like are omitted in FIG.
[0052]
Next, a manufacturing process of the memory device of Example 4 will be described. The manufacturing process includes a planar memory layer forming process for forming a planar memory layer having a simple matrix structure, and a winding process (5) for stacking a plurality of memory layers by spirally winding the planar memory layer in a predetermined direction. Yes.
[0053]
The planar memory layer forming step can be performed in the same manner as steps (1) to (4) of the first embodiment.
[0054]
In the winding process, the memory layer is stacked by winding the planar memory layer as shown in FIG. After entrainment, the shape may be retained by adhesion or the like, or may be fixed in a housing.
[0055]
In this embodiment, since the Y-direction linear electrode is short-circuited (connected) for all layers, the number of connection terminals and the number of detection / drive circuits can be reduced as compared with the conventional memory device. Can be simplified. As a result, the reliability and yield of the circuit can be improved. Further, since the detection / drive circuit is shared for the linear electrodes in the Y direction, the area (volume) occupied by these circuits can be reduced, and the memory device can be made compact.
[0056]
Furthermore, in this embodiment, a configuration in which the Y-direction linear electrodes are short-circuited (connected) can be realized by winding the planar memory layer, and therefore the step of forming a through-hole and short-circuiting can be omitted.
(Example 5)
In this example, in the structure of FIG. 1, FIG. 2 (a) and FIG. 2 (b) of Example 1, the X-direction linear electrode (11) is further short-circuited in the stacking direction. An electrode is provided. FIG. 19 is a diagram schematically showing an XZ cross section (see FIG. 1) of the memory device of the present embodiment.
[0057]
The structure shown in FIG. 19 is described in detail. In the structure shown in FIG. 2, n layers of memory layers are stacked, and a memory cell is formed at the intersection of the X-direction linear electrode 11 and the Y-direction linear electrode 13. It is formed. Further, a layer selection electrode 15 sandwiched between insulating layers (16, 17) is provided between the stacked bodies (X direction linear electrode 11 / memory layer 12 / Y direction linear electrode 13) sandwiching each memory layer. It is provided so as to cover the entire surface or the range of all memory cells. The X direction linear electrode 11 and the Y direction linear electrode 13 are both short-circuited in the stacking direction, and the detection / drive circuit 101 is connected to each layer in common. On the other hand, the layer selection electrode 15 is connected to the detection / drive circuit 103, but each layer can be selected.
[0058]
In the memory device of this embodiment, when a ferroelectric layer is used as the memory layer 12, a write operation is performed as follows. First, as shown in FIG. 19, when the memory cells A, B, and C in the respective layers located at corresponding positions in the stacking direction are polarized as shown in FIG. 19, for example, −V / 2. V / 2 is applied to the Y-direction linear electrode 13 (V is a ferroelectric saturation voltage), and at the same time, an electric field of V / 2 or more (less than 3 V / 2) is selectively applied to the layer selection electrode 15. (In FIG. 19, it is applied to the uppermost layer and the lowermost layer, and not applied to the middle layer). At this time, the voltage V is applied to the memory cell B corresponding to the layer to which no voltage is applied to the layer selection electrode, but the memory cells A and C corresponding to the layer to which the voltage is applied to the layer selection electrode A desired potential difference does not occur between the electrodes (V / 2 or less), and the polarization state shown in the figure does not change. Thus, by applying a voltage to the X-direction linear electrode 11 and the Y-direction linear electrode and selecting the layer selection electrode 15 (selective voltage application), a desired voltage is applied to each memory cell to write or Read operation is performed.
(Other variations)
The memory device manufactured according to the present invention can be used for all electronic devices including a memory, for example, an internal storage device of a computer, a memory stick, and a memory card.
[0059]
The present invention is not limited to the above-described embodiments, and can be applied with various modifications. For example, the present invention can use a dielectric layer instead of the ferroelectric layer. Further, instead of the ferroelectric layer, a charge transfer complex material whose impedance changes with voltage and takes a binary value can be used as a non-volatile memory having a simple matrix structure.
[0060]
【The invention's effect】
The memory device according to the present invention has a configuration in which the number of detection / drive circuits and connection terminals can be reduced by adopting a configuration in which linear electrodes in the X direction or the Y direction are short-circuited for a plurality of layers, and the circuit configuration is simple and compact. A simple memory device can be realized.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of a memory device according to a first embodiment.
FIG. 2 is a schematic diagram illustrating a cross section of the memory device according to the first embodiment.
FIG. 3 is a diagram for explaining a principle capable of selecting an arbitrary memory cell;
FIG. 4 is a diagram illustrating a manufacturing process of the memory device according to the first embodiment.
FIG. 5 is a diagram for explaining a position of a through hole.
FIG. 6 is a diagram for explaining a connection terminal forming step of an X-direction linear electrode.
7 is a schematic perspective view of a memory device according to Embodiment 2. FIG.
FIG. 8 is a schematic diagram illustrating a cross section of a memory device according to a second embodiment.
FIG. 9 is a diagram illustrating a manufacturing process of the memory device according to the second embodiment.
10 is a schematic perspective view of a memory device according to Example 3. FIG.
FIG. 11 is a schematic diagram illustrating a cross section of a memory device according to a third embodiment.
FIG. 12 is a diagram illustrating a folding process.
FIG. 13 is a schematic perspective view of a memory device according to a fourth embodiment.
14 is a schematic diagram illustrating a cross section of a memory device according to Embodiment 4. FIG.
FIG. 15 is a diagram for explaining a memory device having a simple matrix structure;
FIG. 16 is a diagram showing an equivalent circuit of a memory device having a simple matrix structure.
FIG. 17 is a diagram for explaining the arrangement of detection / drive circuits of a memory device having a simple matrix structure;
FIG. 18 is a diagram for explaining a memory device having a simple matrix structure and a layer structure in the prior art.
19 is a cross-sectional view schematically showing the structure of a memory device according to Example 5. FIG.
[Explanation of symbols]
10 Substrate
11 X direction linear electrode
12 Memory layer
13 Y-direction linear electrode
14, 16, 17 Insulating layer
15 layer selection electrode
100 memory layers
101 Detection / Drive circuit
200, 201, 301-309, A, B, C Memory cells

Claims (12)

A memory device in which memory layers are stacked,
Each memory layer has a simple matrix structure in which memory cells are formed at the intersections of the X direction linear electrodes and the Y direction linear electrodes.
Regarding a plurality of stacked memory layers, at least one of the linear electrodes in the X direction or the Y direction is short-circuited between the plurality of layers, and the other linear electrode is configured such that a voltage can be applied independently between the plurality of layers. A memory device characterized by being made. 2. The memory device according to claim 1, wherein one linear electrode in the X direction or the Y direction is short-circuited between the plurality of layers. 3. The memory device according to claim 1, wherein a plurality of the plurality of layers are provided in a stacked memory layer. 4. The memory device according to claim 1, wherein the number of the plurality of layers is the number of bits of 1 word in the memory device or an integer multiple thereof. 5. The memory device according to claim 1, wherein the plurality of layers are formed by stacking one memory layer having a simple matrix structure. 5. Memory device according to any one of claims 1 to 5 wherein the memory layer is characterized by a ferroelectric. Memory device according to any one of claims 1 to 5 wherein the memory layer is characterized by a charge transfer complex. An electronic apparatus comprising the memory device according to claim 1 as a memory. A method of manufacturing a memory device in which memory layers are stacked,
Laminating a memory layer having a simple matrix structure in which memory cells are formed at intersections of the X-direction linear electrodes and the Y-direction linear electrodes;
And a step of short-circuiting at least one of the linear electrodes in the X direction or the Y direction between the plurality of layers with respect to a plurality of the stacked memory layers. 10. The method of manufacturing a memory device according to claim 9 , wherein the short-circuiting step is a step of short-circuiting one linear electrode in the X direction or the Y direction between the plurality of layers. The method of manufacturing a memory device according to claim 9 , wherein the short-circuiting step is performed on a plurality of sets of the plurality of layers. 12. The method of manufacturing a memory device according to claim 9, wherein the number of layers of the plurality of layers is the number of bits of 1 word in the memory device or an integer multiple thereof.

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