Memory element

Abstract

Provided is a memory element having a reduced occupied area. A vertical channel type transistor is used as a transistor connected to an SOT-MTJ element (spin-orbit torque magnetic tunnel junction element) of one storage element. By using the vertical channel type transistor, the occupied area of the memory element can be reduced. In addition, by using the oxide semiconductor in the channel formation region of the vertical channel type transistor, it is possible to achieve a storage element that is stable and highly reliable in write operation and read operation even in a high-temperature environment.

Description

Technical Field

[0001] One aspect of the present invention relates to a storage element.

[0002] Note that one aspect of the present invention is not limited to the aforementioned technical fields. The technical fields of the invention disclosed in this specification relate to an object, a method of operation, or a method of manufacturing. Furthermore, one aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter. Therefore, specifically, examples of the technical fields of one aspect of the present invention disclosed in this specification include semiconductor devices, display devices, light-emitting devices, energy storage devices, imaging devices, storage devices (memory), signal processing devices, sensors, processors, electronic devices, systems, methods of driving them, methods of manufacturing them, or methods of inspecting them. Background Technology

[0003] In recent years, with the increase in the amount of data used, there is a need for storage devices with larger storage capacities. In order to increase the storage capacity per unit area, it is effective to stack storage elements (also known as storage cells) as in 3D NAND type storage devices (see Patent Documents 1 to 3). By stacking storage elements, the storage capacity per unit area can be increased accordingly with the number of stacked storage cells.

[0004] [Preliminary Technology Documents]

[0005] [Patent Literature]

[0006] [Patent Document 1] U.S. Patent Application Publication No. 2011 / 0065270

[0007] [Patent Document 2] U.S. Patent Application Publication No. 2016 / 0149004

[0008] [Patent Document 3] U.S. Patent Application Publication No. 2013 / 0069052 Summary of the Invention

[0009] The technical problem that the invention aims to solve

[0010] To increase storage capacity per unit area, it is necessary not only to reduce the stacking of storage elements, but also to reduce the area occupied by a single storage element.

[0011] One objective of this invention is to provide a storage element with a reduced footprint. Another objective of this invention is to provide a storage element with high reliability. Another objective of this invention is to provide a storage element with low power consumption. Another objective of this invention is to provide a novel storage element. Furthermore, one objective of this invention is to provide a storage device with a reduced footprint. Another objective of this invention is to provide a storage device with high storage density (storage capacity per unit area). Another objective of this invention is to provide a storage device with high reliability. Another objective of this invention is to provide a storage device with low power consumption. Another objective of this invention is to provide a novel storage device.

[0012] Note that the purpose of one aspect of the present invention is not limited to the purposes listed above. The purposes listed above do not preclude the existence of other purposes. Furthermore, other purposes are those not mentioned above but will be described in the following description. Those skilled in the art can derive and appropriately extract purposes other than those listed above from the description, drawings, etc. Moreover, one aspect of the present invention does not need to achieve all of the above-mentioned and other purposes. Furthermore, one aspect of the present invention achieves at least one of the above-listed and other purposes.

[0013] means of solving technical problems

[0014] (1) One aspect of the present invention is a storage element comprising a conductive layer, a magnetic tunnel junction element and a transistor, wherein the magnetic tunnel junction element is disposed overlapping the conductive layer, one of the source electrode and the drain electrode of the transistor is electrically connected to the conductive layer, one of the source electrode and the drain electrode of the transistor has a region on the insulating layer, the other of the source electrode and the drain electrode of the transistor has a region under the insulating layer, and the channel forming region of the transistor has a region along the side of the insulating layer.

[0015] Furthermore, in (1), the resistance value of the magnetic tunnel junction element is controlled according to the direction of the current supplied to the conductive layer through the transistor. As the semiconductor layer of the transistor, an oxide semiconductor is preferably used. Additionally, the conductive layer may have a region in contact with the semiconductor layer of the transistor.

[0016] (2) Another aspect of the present invention is a storage element comprising a conductive layer, a magnetic tunnel junction element, a first transistor, and a second transistor, wherein the magnetic tunnel junction element is disposed overlapping the conductive layer, one of the source electrode and drain electrode of the first transistor is electrically connected to one of the source electrode and drain electrode of the second transistor through at least a region of the conductive layer overlapping the magnetic tunnel junction element, one of the source electrode and drain electrode of the first transistor has a region on the insulating layer, the other of the source electrode and drain electrode of the first transistor has a region under the insulating layer, the channel forming region of the first transistor has a region along a first side of the insulating layer, one of the source electrode and drain electrode of the second transistor has a region on the insulating layer, the other of the source electrode and drain electrode of the second transistor has a region under the insulating layer, and the channel forming region of the second transistor has a region along a second side of the insulating layer.

[0017] Furthermore, in (2), the resistance value of the magnetic tunnel junction element is controlled according to the direction of the current supplied to the conductive layer through the first transistor or the second transistor. Oxide semiconductor is preferably used as the semiconductor layer of the transistor. Oxide semiconductor is preferably used as the semiconductor layer of the first transistor. Oxide semiconductor is preferably used as the semiconductor layer of the second transistor. The conductive layer may have a region that contacts the semiconductor layer of the first transistor or a region that contacts the semiconductor layer of the second transistor.

[0018] Invention Effects

[0019] According to one aspect of the present invention, a storage element with reduced footprint can be provided. Additionally, a storage element with high reliability can be provided. Furthermore, a storage element with low power consumption can be provided. Additionally, a novel storage element can be provided. Moreover, a storage device with reduced footprint can be provided. Furthermore, a storage device with high storage density can be provided. Furthermore, a storage device with high reliability can be provided. Furthermore, a storage device with low power consumption can be provided. Furthermore, a novel storage device can be provided.

[0020] Note that the effects of one aspect of the present invention are not limited to those described above. The effects listed above do not preclude the existence of other effects. Therefore, one aspect of the present invention may sometimes not have the effects listed above. Other effects refer to effects other than those described above, which will be described in the following description. Those skilled in the art can derive and appropriately extract effects other than those listed above from the description in the specification or drawings, etc. One aspect of the present invention has at least one of the effects listed above and other effects. Attached Figure Description

[0021] Figure 1A It is a plan view of the storage element. Figure 1BThis is a cross-sectional view of the storage element.

[0022] Figures 2A to 2C It is the equivalent circuit diagram of the storage element.

[0023] Figure 3A It is a plan view of the storage element. Figure 3B This is a cross-sectional view of the storage element.

[0024] Figure 4A This is a cross-sectional view of the storage element. Figure 4B It is the equivalent circuit diagram of the storage element.

[0025] Figure 5A It is a plan view of the storage element. Figure 5B This is a cross-sectional view of the storage element.

[0026] Figure 6A It is a plan view of the storage element. Figure 6B This is a cross-sectional view of the storage element.

[0027] Figure 7A It is a plan view of the storage element. Figure 7B This is a cross-sectional view of the storage element.

[0028] Figure 8A This is a cross-sectional view of the storage element. Figure 8B It is the equivalent circuit diagram of the storage element.

[0029] Figure 9A It is a plan view of the storage element. Figure 9B This is a cross-sectional view of the storage element.

[0030] Figure 10 This is a cross-sectional view of the storage element.

[0031] Figure 11A It is a plan view of the storage element. Figure 11B This is a cross-sectional view of the storage element.

[0032] Figure 12A It is a plan view of the storage element. Figure 12B This is a cross-sectional view of the storage element.

[0033] Figure 13A This is a cross-sectional view of the storage element. Figure 13B It is the equivalent circuit diagram of the storage element.

[0034] Figure 14 This is a cross-sectional view of the storage element.

[0035] Figure 15 This is a cross-sectional view of the storage element.

[0036] Figures 16A to 16E This is a diagram illustrating an example of transistor structure.

[0037] Figure 17A and Figure 17B This is a diagram illustrating an example of transistor structure.

[0038] Figure 18 This is a diagram illustrating an example of transistor structure.

[0039] Figure 19A and Figure 19B This is a diagram illustrating an example of transistor structure.

[0040] Figures 20A to 20C This is a diagram illustrating a storage device.

[0041] Figure 21 This is a diagram illustrating an example of the structure of a storage device.

[0042] Figure 22 It is a 3D diagram of a semiconductor device.

[0043] Figure 23A and Figure 23B This is a diagram that shows various storage devices in a hierarchical manner.

[0044] Figures 24A to 24J It is a three-dimensional diagram or schematic diagram illustrating an example of an electronic device.

[0045] Figures 25A to 25C This is a diagram illustrating an example of an electronic device. Detailed Implementation

[0046] The embodiments will now be described with reference to the accompanying drawings. However, those skilled in the art will readily understand that the embodiments can be implemented in many different forms, and their manner and details can be varied in various ways without departing from the spirit and scope of the invention. Therefore, the invention should not be construed as being limited to the contents described in the embodiments shown below.

[0047] In this specification, etc., a semiconductor device refers to a device that utilizes the properties of semiconductors, and includes circuits containing semiconductor elements (transistors, diodes, photodiodes, etc.) and devices having such circuits. Furthermore, a semiconductor device refers to all devices capable of functioning by utilizing the properties of semiconductors. Examples of semiconductor devices include integrated circuits, chips containing integrated circuits, and electronic components that house chips in packages. In addition, storage devices, display devices, light-emitting devices, lighting devices, and electronic devices are themselves semiconductor devices, and sometimes include semiconductor devices.

[0048] In the accompanying drawings and other materials of this specification, sizes, layer thicknesses, or areas are sometimes exaggerated for clarity. Therefore, the invention is not limited to the sizes or aspect ratios shown in the drawings. Furthermore, while ideal examples are schematically illustrated in the drawings, the invention is not limited to the shapes, values, etc., shown in the drawings.

[0049] Note that in the structure of the invention as described in the embodiments, the same reference numerals are sometimes used in different figures to indicate the same parts or parts with the same function, and repeated descriptions are omitted. Furthermore, when indicating parts with the same function, the same shading lines are sometimes used without additional reference numerals. In perspective views, plan views, etc., illustrations of some constituent elements are sometimes omitted for clarity.

[0050] In this specification, ordinal numbers such as "first," "second," and "third" are added to avoid confusion regarding the constituent elements. Therefore, these ordinal numbers do not limit the number of constituent elements. Furthermore, these ordinal numbers do not limit the order of the constituent elements. For example, a constituent element marked "first" in one embodiment of this specification may be marked "second" in other embodiments or claims. Furthermore, for example, a constituent element marked "first" in one embodiment of this specification may be omitted in other embodiments or claims.

[0051] In this specification and other materials, for convenience, terms such as "above," "below," "above," and "below" are sometimes used to indicate the arrangement of components in conjunction with the accompanying drawings. Furthermore, the positional relationships of the components may be appropriately changed depending on the orientation of each structure being described. Therefore, the use of terms not limited to those described in the specification and other materials may be appropriately changed as needed. For example, the expression "an insulator located on the top surface of a conductor" can be replaced with "an insulator located below a conductor" by rotating the orientation of the shown drawings by 180 degrees.

[0052] Furthermore, terms like "above" and "below" are not limited to situations where the constituent elements are positioned "directly above" or "directly below" and in direct contact. For example, if the statement is "electrode B on insulating layer A," it is not necessary for electrode B to be formed in direct contact with insulating layer A; it could also include situations where other constituent elements are included between insulating layer A and electrode B.

[0053] In this specification, the term "overlapping" does not limit the state of the stacking order of the constituent elements. For example, "electrode B overlapping with insulating layer A" is not limited to the state of "electrode B is formed on insulating layer A", but also includes the state of "electrode B is formed under insulating layer A" or "electrode B is formed on the right (or left) side of insulating layer A", etc.

[0054] In this specification and other documents, terms such as "adjacent" and "near" do not limit the state of direct contact between constituent elements. For example, if the description is "electrode B adjacent to insulating layer A", it does not necessarily mean that insulating layer A and electrode B are in direct contact; it may also include situations where other constituent elements are included between insulating layer A and electrode B.

[0055] In this specification and other materials, the terms "film" and "layer" may be interchanged depending on the context. For example, "conductive layer" may sometimes be replaced with "conductive film." Additionally, "insulating film" may sometimes be replaced with "insulating layer." Furthermore, depending on the situation or state, other terms may be used instead of "film" and "layer." For example, "conductive layer" or "conductive film" may sometimes be replaced with "conductor." Additionally, "conductor" may sometimes be replaced with "conductive layer" or "conductive film." Furthermore, for example, "insulating layer" or "insulating film" may sometimes be replaced with "insulator." Additionally, "insulator" may sometimes be replaced with "insulating layer" or "insulating film."

[0056] Note that voltage refers to the potential difference between two points, while potential refers to the electrostatic energy (potential energy) of a unit charge at a point in an electrostatic field. Generally, the potential difference between a point and a standard potential (e.g., ground potential) is simply referred to as potential or voltage, and in many cases, potential and voltage are synonymous. Therefore, in this specification and other documents, unless specifically specified, "potential" may be referred to as "voltage," and "voltage" may be referred to as "potential."

[0057] In this specification, the terms "electrode," "wiring," and "terminal" do not functionally limit their constituent elements. For example, sometimes "electrode" is used as part of "wiring," and vice versa. Furthermore, "electrode" or "wiring" also includes cases where multiple "electrodes" or "wiring" are formed as one unit. Similarly, sometimes "terminal" is used as part of "wiring" or "electrode," and vice versa. Furthermore, the term "terminal" includes cases where multiple "electrodes," "wiring," and "terminals" are formed as one unit. Therefore, for example, an "electrode" can be part of "wiring" or "terminal," and vice versa. Furthermore, the terms "electrode," "wiring," and "terminal" are sometimes replaced with terms such as "area."

[0058] In this instruction manual and other documents, the terms "wiring," "signal line," and "power line" may be interchanged depending on the situation or state. For example, sometimes "wiring" may be replaced with "signal line." Similarly, sometimes "wiring" may be replaced with "power line," etc. Conversely, sometimes "signal line" or "power line" may be replaced with "wiring." Sometimes "power line," etc., may be replaced with "signal line," etc. Conversely, sometimes "signal line," etc., may be replaced with "power line," etc. Furthermore, depending on the situation or state, the "potential" applied to the wiring may be interchanged with "signal," etc. Conversely, sometimes "signal," etc., may be replaced with "potential."

[0059] In this specification, the term "X and Y connection" includes both electrical and functional connections between X and Y. Here, X and Y refer to objects (e.g., devices, components, circuits, wiring, electrodes, terminals, conductive films, layers, etc.). Therefore, the scope is not limited to the specified connection relationships such as those shown in the drawings or text, but also includes relationships other than those shown in the drawings or text.

[0060] As examples of the electrical connection between X and Y, there are cases where X and Y are directly connected in the equivalent circuit, and cases where more than one element (e.g., switch, transistor, inductor, resistor, etc.) is connected between X and Y to achieve the electrical connection between X and Y.

[0061] As an example of a functional connection between X and Y, more than one circuit capable of functionally connecting X and Y can be connected between X and Y (e.g., logic circuits (inverters, NAND circuits, NOR circuits, etc.), signal conversion circuits (DA converters, AD converters, gamma correction circuits, etc.), potential level conversion circuits (power supply circuits (boost circuits, buck circuits, etc.), level converter circuits that change the potential level of a signal, etc.), voltage sources, current sources, switching circuits, amplification circuits (circuits that can increase signal amplitude or current, operational amplifiers, differential amplifiers, source follower circuits, buffer circuits, etc.), signal generation circuits, storage circuits, control circuits, etc.). Furthermore, as an example, even when other circuits are included between X and Y, it can still be said that X and Y are functionally connected when the signal output from X is transmitted to Y.

[0062] In this specification and other documents, unless otherwise stated, the use of terms such as “same,” “identical,” “equal,” “uniform” (including synonyms of these terms) for count or measurement values ​​includes a variation of ±20% as an error.

[0063] In addition, arrows indicating the X, Y, and Z directions are sometimes included in the accompanying drawings and other materials of this specification. In this specification, "X direction" refers to the direction along the X-axis, and unless otherwise specified, the distinction between clockwise and counterclockwise directions is sometimes made. The same applies to "Y direction" and "Z direction." Furthermore, the X, Y, and Z directions are intersecting directions. More specifically, the X, Y, and Z directions are orthogonal directions.

[0064] In this specification and other materials, when multiple constituent elements use the same symbol and it is necessary to distinguish them, symbols such as "A", "b", "_1", "[n]", and "[m,n]" are sometimes added to the symbol for identification. For example, opening 162 is sometimes represented as opening 162a, opening 162b, opening 162c, etc.

[0065] (Implementation Method 1)

[0066] A storage element 100A according to one aspect of the present invention will be described. Figure 1A and Figure 1B This is a schematic diagram illustrating an example of the structure of a memory element 100A, one of the semiconductor devices. Figure 1A This is a plan view of storage element 100A. Additionally, Figure 1B It is along Figure 1A A cross-sectional view of the section with the dotted lines A1-A2 in the figure.

[0067] According to one aspect of the present invention, a storage element 100A includes a variable resistance element 600, a transistor 233, and a transistor 234. The variable resistance element 600 includes an MTJ (Magnetic Tunnel Junction) element (also known as a "magnetic tunnel junction element") 620 and a conductive layer 610.

[0068] As MTJ devices, two-terminal memory devices (also known as "STT-MTJ devices") that read and write data using Spin Transfer Torque (STT) and three-terminal memory devices (also known as "SOT-MTJ devices") that read and write data using Spin Orbit Torque (SOT) are known. SOT-MTJ devices have more terminals than STT-MTJ devices, therefore occupying a larger area. On the other hand, SOT-MTJ devices have faster write speeds and higher rewrite tolerance than STT-MTJ devices.

[0069] Note that a memory device using multiple STT-MTJ elements is called an STT-MRAM (Spin Transfer Torque-Magnetoresistive Random Access Memory). Additionally, a memory device using multiple SOT-MTJ elements is called an SOT-MRAM (Spin Orbit Torque-Magnetoresistive Random Access Memory).

[0070] According to one aspect of the present invention, the storage element 100A is a three-terminal storage element used as an SOT-MTJ element. According to one aspect of the present invention, the storage element 100A is a non-volatile storage element that can retain written data for a long period even when the power supply is interrupted.

[0071] <Example of storage element structure>

[0072] right Figure 1A and Figure 1B The structure of the storage element 100A shown will be described using an example. The storage element 100A includes conductive layers 155a and 155b on the insulating layer 154. Furthermore, the storage element 100A includes an insulating layer 157 on the insulating layer 154, conductive layers 155a and 155b, an insulating layer 158 on the insulating layer 157, and an insulating layer 159 on the insulating layer 158. Sometimes, insulating layers 157, 158, and 159 are collectively referred to as insulating layer 156 or a spacer layer. Additionally, conductive layers 161a and 161b are included on the insulating layer 159.

[0073] Additionally, in the region that overlaps with a portion of conductive layer 155a when viewed from the Z direction, an opening 162a is included in conductive layer 161a, insulating layer 159, insulating layer 158, and insulating layer 157. Furthermore, in the region that overlaps with a portion of conductive layer 155b when viewed from the Z direction, an opening 162b is included in conductive layer 161b, insulating layer 159, insulating layer 158, and insulating layer 157.

[0074] Additionally, a semiconductor layer 163a covering the opening 162a is included on the opening 162a, and a semiconductor layer 163b covering the opening 162b is included on the opening 162b.

[0075] Semiconductor layer 163a has a region overlapping the bottom of opening 162a and a region overlapping the side of opening 162a. Semiconductor layer 163a has a region in opening 162a that contacts the side of insulating layer 156. That is, semiconductor layer 163a has a region in opening 162a that contacts the side of insulating layer 157, a region that contacts the side of insulating layer 158, and a region that contacts the side of insulating layer 159.

[0076] Additionally, semiconductor layer 163a has a region contacting conductive layer 155a and a region contacting conductive layer 161a. That is, a portion of semiconductor layer 163a is electrically connected to conductive layer 155a, and another portion of semiconductor layer 163a is electrically connected to conductive layer 161a. Furthermore, semiconductor layer 163a may also have a region extending beyond the end of conductive layer 161a (see reference). Figure 1A ).

[0077] Furthermore, the semiconductor layer 163b has a region overlapping the bottom of the opening 162b and a region overlapping the side of the opening 162b. The semiconductor layer 163b has a region in the opening 162b that contacts the side of the insulating layer 156. That is, the semiconductor layer 163b has regions that contact the side of the insulating layer 157, regions that contact the side of the insulating layer 158, and regions that contact the side of the insulating layer 159.

[0078] Additionally, semiconductor layer 163b has a region that contacts conductive layer 155b and a region that contacts conductive layer 161b. That is, a portion of semiconductor layer 163b is electrically connected to conductive layer 155b, and another portion of semiconductor layer 163b is electrically connected to conductive layer 161b. Furthermore, semiconductor layer 163b may also have a region extending beyond the end of conductive layer 161b (see reference). Figure 1A ).

[0079] Additionally, an insulating layer 164 is included on the insulating layer 159, conductive layers 161a, 161b, semiconductor layers 163a and 163b. Furthermore, conductive layers 165a and 165b are included on the insulating layer 164. The conductive layer 165a has a region overlapping with the opening 162a, and in this region, it has regions that overlap with the sides and bottom of the opening 162a through the insulating layer 164 and the semiconductor layer 163a. ​​The conductive layer 165b has a region overlapping with the opening 162b, and in this region, it has regions that overlap with the sides and bottom of the opening 162b through the insulating layer 164 and the semiconductor layer 163b. Note that... Figure 1A and Figure 1BThe structural example shown illustrates an example where a portion of conductive layer 165 is used as conductive layer 165a and another portion is used as conductive layer 165b. Therefore, in this specification, conductive layer 165 sometimes includes both conductive layer 165a and conductive layer 165b.

[0080] The thickness of the semiconductor layer 163 is preferably 1 nm or more and 20 nm or less, more preferably 3 nm or more and 15 nm or less, even more preferably 5 nm or more and 12 nm or less, and still more preferably 5 nm or more and 10 nm or less. The thickness of the insulating layer 164 is preferably 0.5 nm or more and 15 nm or less, more preferably 0.5 nm or more and 12 nm or less, and even more preferably 0.5 nm or more and 10 nm or less. At least a portion of the insulating layer 164 may be a region having the above-mentioned thickness.

[0081] Additionally, an insulating layer 166 is included on the insulating layer 164. Furthermore, it is preferable that the top surfaces (positions in the Z direction) of the conductive layers 165a, 165b, and insulating layer 166 are aligned or substantially aligned. For example, by performing a chemical mechanical polishing (CMP) process, the top surfaces of the conductive layers 165 and insulating layer 166 can be aligned or substantially aligned. By aligning or substantially aligning the top surfaces of the conductive layers 165 and insulating layer 166, the coverage of the subsequently formed insulating and conductive layers can be improved.

[0082] Additionally, an insulating layer 167 is included on the conductive layer 165 and the insulating layer 166, and a conductive layer 610 is included on the insulating layer 167. Furthermore, a conductive layer 168a, which passes through the insulating layers 167, 166, and 164, is included in the region overlapping with the conductive layer 161a when viewed from the Z direction. Similarly, a conductive layer 168b, which passes through the insulating layers 167, 166, and 164, is included in the region overlapping with the conductive layer 161b when viewed from the Z direction. The conductive layer 168a is electrically connected to a first region 611 of the conductive layer 610, and the conductive layer 168b is electrically connected to a second region 612 of the conductive layer 610. Therefore, the conductive layer 610 is electrically connected to the conductive layer 161a via the conductive layer 168a. Additionally, the conductive layer 610 is electrically connected to the conductive layer 161b via the conductive layer 168b. Both the conductive layers 168a and 168b serve as contact plugs.

[0083] Additionally, when viewed from the Z direction, the MTJ element 620 is included in the region of conductive layer 610 that does not overlap with conductive layers 168a and 168b. Note that the region of conductive layer 610 that overlaps with the MTJ element 620 is sometimes referred to as the third region 613. The third region 613 is located between the first region 611 and the second region 612. More specifically, the third region 613 is included midway along the path connecting the first region 611 to the second region 612 of conductive layer 610 when viewed from the Z direction.

[0084] The MTJ element 620 includes a first magnetic layer 601, an insulating layer 602, and a second magnetic layer 603. The first magnetic layer 601 is disposed overlapping the conductive layer 610. The insulating layer 602 is disposed on the first magnetic layer 601, and the second magnetic layer 603 is disposed on the insulating layer 602. There are areas where they overlap with each other across the insulating layer 602.

[0085] Additionally, an insulating layer 614 is included on the insulating layer 167, the conductive layer 610, and the MTJ element 620. Furthermore, an insulating layer 615 is included on the insulating layer 614. A conductive layer 616, passing through the insulating layer 615 and the insulating layer 614, is included in the region overlapping with the second magnetic layer 603.

[0086] Furthermore, a conductive layer 617 is included on the insulating layer 615 and the conductive layer 616. The conductive layer 617 is electrically connected to the second magnetic layer 603 through the conductive layer 616. The conductive layer 616 serves as a contact plug.

[0087] Conductive layer 165 is used as wiring WL to control the writing and reading of data from memory element 100A. The on and off states of transistors 233 and 234 can be controlled according to the potential supplied to conductive layer 165. Conductive layer 617 is used as wiring RBL for reading data. Conductive layer 155a is used as wiring WBLa for writing data, and conductive layer 155b is used as wiring WBLb for writing data. The data written to memory element 100A depends on the direction of the current flowing between wiring WBLa and wiring WBLb.

[0088] Viewed from the Z direction, the storage element 100A includes regions where transistors 233, variable resistor 600, and transistor 234 overlap with the conductive layer 617, and are arranged in a straight line (see reference). Figure 1A By overlapping transistor 233, variable resistor 600, and transistor 234 with conductive layer 617, the area occupied by storage element 100A can be reduced.

[0089] Conductive layer 161a is used as one of the source and drain electrodes of transistor 233, and conductive layer 155a is used as the other of the source and drain electrodes of transistor 233. More specifically, the region of conductive layer 161a that contacts semiconductor layer 163a is used as one of the source and drain electrodes of transistor 233. Additionally, the region of conductive layer 155a that contacts semiconductor layer 163a is used as the other of the source and drain electrodes of transistor 233.

[0090] Conductive layer 161b is used as one of the source and drain electrodes of transistor 234, and conductive layer 155b is used as the other of the source and drain electrodes of transistor 234. More specifically, the region of conductive layer 161b that contacts semiconductor layer 163b is used as one of the source and drain electrodes of transistor 234. Furthermore, the region of conductive layer 155b that contacts semiconductor layer 163b is used as the other of the source and drain electrodes of transistor 234.

[0091] Transistors 233 and 234 are used as vertical transistors (transistors containing a component whose channel length direction is perpendicular to the Z direction, the height direction, or the direction in which the transistor is formed). Vertical transistors will be described in detail later.

[0092] Furthermore, transistors 233 and 234 are preferably oxide semiconductor transistors (also known as OS transistors) in the channel formation region. Because OS transistors have significantly low off-state current, leakage current when the memory element 100A is in standby mode (a state where no data is being written or read) can be significantly reduced. Therefore, the power consumption of the memory element 100A can be reduced. Additionally, when multiple memory elements 100A are configured in a matrix and used in a memory device, by using OS transistors as the transistors constituting the memory elements 100A, crosstalk caused by leakage current between the multiple memory elements 100A is less likely to occur. Therefore, the reliability of the memory device can be improved.

[0093] Furthermore, in the storage element 100A, conductive layer 165 and conductive layer 617 extend in the X direction. Additionally, in the storage element 100A, conductive layer 155a and conductive layer 155b extend in the Y direction. The conductive layer 165, used as wiring WL, preferably intersects at least one of wiring WBLa and wiring WBLb. Furthermore, the conductive layer 617, used as wiring RBL, preferably intersects at least one of conductive layer 155a used as wiring WBLa and conductive layer 155b used as wiring WBLb. Note that wiring WBLa and wiring WBLb may also not extend parallel to each other.

[0094] Figure 2A The equivalent circuit diagram of storage element 100A is shown.

[0095] <Variable Resistive Element>

[0096] The structure of the variable resistor element 600 will be described. As described above, the variable resistor element 600 is composed of an MTJ element 620 and a conductive layer 610. The conductive layer 610 uses a material that generates the spin Hall effect. Specifically, a metal material with strong spin-orbit interaction is preferred. Examples of such metal materials include tungsten, platinum, and tantalum. Ruthenium oxide can also be used. Furthermore, the conductive layer 610 may also contain a topological insulator that generates the spin Hall effect; in this case, for example, an alloy of bismuth and antimony or an alloy of bismuth and selenium may be used.

[0097] The first magnetic layer 601 serves as a free layer in the MTJ element 620. The first magnetic layer 601 can be in a state where the magnetic moment is parallel or antiparallel to the magnetization direction of the second magnetic layer 603. As the ferromagnetic material used for the first magnetic layer 601, a material whose magnetization is reversed due to a small spin current is preferably used. Furthermore, a material that is not easily reversed by heat is preferred. As the ferromagnetic material used for the first magnetic layer 601, an alloy selected from one or more of iron, cobalt, and nickel can be used, for example. For example, an alloy of cobalt, iron, and boron (CoFeB) can be used. Furthermore, alloys of manganese and gallium (MgGa) and manganese and germanium (MgGe) are also examples.

[0098] The magnetic moment of the first magnetic layer 601 is subjected to spin torque due to the spin current generated in the conductive layer 610. When this spin torque exceeds a threshold, the magnetization direction of the first magnetic layer 601 is reversed. In other words, when current flows from the first region 611 to the second region 612 of the conductive layer 610, the magnetization direction of the first magnetic layer 601 can be determined according to the direction of the current. For example, by recording the case where the magnetization directions of the first magnetic layer 601 and the second magnetic layer 603 are parallel as data "0" and the case where they are antiparallel as data "1", 1 bit of data can be recorded in the MTJ element 620.

[0099] Insulating layer 602 is used as a tunneling insulating layer in the MTJ element 620. By applying a voltage between the first magnetic layer 601 and the second magnetic layer 603, tunneling current can flow through insulating layer 602. At this time, the resistance of the MTJ element 620 varies according to the direction of the magnetic moment of the first magnetic layer 601. Specifically, the resistance of the MTJ element 620 varies depending on whether the magnetization directions of the first magnetic layer 601 and the second magnetic layer 603 are parallel or antiparallel. This phenomenon is called the tunneling magnetoresistance effect (TMR effect). The magnitude of the TMR effect is represented by the difference between the resistance when the magnetization direction is parallel and the resistance when it is antiparallel, divided by the resistance when the magnetization direction is parallel (magnetoresistance ratio, also known as the "MR ratio"). Note that the MTJ element is a device that utilizes the TMR effect, so it is sometimes called a TMR element.

[0100] As the insulating layer 602 used as the tunnel insulation layer, magnesium oxide, aluminum oxide, etc., can be used, for example. In particular, crystalline magnesium oxide is preferred. By using crystalline magnesium oxide in the tunnel insulation layer, a high MR ratio can be easily achieved.

[0101] The second magnetic layer 603 serves as a fixed layer (or, also referred to as a "reference layer") in the MTJ element 620. The second magnetic layer 603 comprises a ferromagnetic material. Furthermore, the ferromagnetic material of the second magnetic layer 603 differs from that of the first magnetic layer 601, and its magnetization direction is fixed. For example, the same ferromagnetic material as that used in the first magnetic layer 601 can be used as the ferromagnetic material for the second magnetic layer 603.

[0102] Furthermore, the ferromagnetic material and tunnel insulation layer contained in the MTJ element 620 are preferably combined in a manner that increases the MR ratio of the MTJ element 620.

[0103] <Examples of how storage elements work>

[0104] Here, refer to Figure 2A The equivalent circuit diagram illustrates an example of a data writing method and an example of a data reading method in storage element 100A. Furthermore, as an example, wiring WBLb is supplied with a low-level potential (potential L).

[0105] [Data Writing]

[0106] When data is written to storage element 100A, firstly, a high-level potential (potential H) is supplied to wiring WL, turning on transistors 233 and 234. Next, a level potential (potential L) is supplied to wiring WBLb, and a first potential higher than potential L is supplied to wiring WBLa. Consequently, a current corresponding to the potential difference flows from the first region 611 to the second region 612 of conductive layer 610. Thus, a spin current is generated in conductive layer 610, and the magnetization direction of the first magnetic layer 601 depends on this spin current. Furthermore, when potential L is supplied to wiring WBLa and the first potential is supplied to wiring WBLb, the direction of the current flowing through conductive layer 610 is reversed. Therefore, the magnetization direction of the first magnetic layer 601 is also reversed.

[0107] In this way, the magnetization direction of the ferromagnetic material in the first magnetic layer 601 is controlled by the direction of the current flowing through the conductive layer 610. By controlling the direction of the current flowing through the conductive layer 610, data "0" or data "1" can be selected and written to the storage element 100A.

[0108] [Data Readout]

[0109] When data is read from storage element 100A, a potential L is supplied to wirings WBLa and WBLb. Additionally, a potential H is supplied to wiring WL, turning on transistors 233 and 234. Next, a second potential higher than L and lower than the first potential is supplied to wiring RBL. Current then flows between wiring RBL and WBLa, and between wiring RBL and WBLb. At this time, the resistance value of MTJ element 620 varies depending on whether the magnetization directions of the first magnetic layer 601 and the second magnetic layer 603 are parallel or antiparallel. Therefore, the amount of tunneling current flowing through the insulating layer 602 of MTJ element 620 also changes. By measuring the current flowing through at least one of wirings RBL, WBLa, and WBLb, the data written to storage element 100A can be read.

[0110] The resistance of the MTJ element 620 varies according to the magnetization direction of the first magnetic layer 601. Therefore, as... Figure 2B As shown in the equivalent circuit diagram, the MTJ element 620 can be represented as a variable resistor.

[0111] <Example 1 of a variation of a storage element>

[0112] like Figure 2C As shown in the equivalent circuit diagram, a structure without transistor 234 can also be used. Figure 3A and Figure 3B An example of the structure of memory element 100B with transistor 234 removed from memory element 100A is shown. Figure 3A This is a plan view of storage element 100B. Additionally, Figure 3B It is along Figure 3A A cross-sectional view of the section with the dotted lines A1-A2 in the figure. Figure 2C The equivalent circuit diagram is the equivalent circuit diagram of storage element 100B. To avoid repetition, the main differences from storage element 100A will be explained.

[0113] Note that in this embodiment, although a structure is shown as storage element 100B in which transistor 234 is removed and transistor 233 remains, a structure in which transistor 233 is removed and transistor 234 remains may also be used.

[0114] Figure 3A and Figure 3B The storage element 100B shown has a structure in which the conductive layer 155b, the opening 162b, and the semiconductor layer 163b are removed from the storage element 100A. The storage element 100B has fewer constituent elements than the storage element 100A, so the occupied area of ​​the storage element can be further reduced.

[0115] In storage element 100B, a reference potential (e.g., ground potential (GND) or common potential (COM)) is supplied to the second region 612 of conductive layer 610 through conductive layer 161b. When data is written, the direction of the current flowing through conductive layer 610 needs to be changed according to the value of the data being written. That is, a potential higher than the reference potential or lower than the reference potential needs to be supplied to wiring WBLa. Therefore, the power required to drive storage element 100B is greater than that required for storage element 100A. In addition, when the reference potential is fixed, the amplitude of the voltage applied between the source and drain of transistor 233 is greater than that of storage element 100A. Therefore, an OS transistor is preferably used as transistor 233. Furthermore, the breakdown voltage between the source and drain of the OS transistor (also known as the drain breakdown voltage) is high. By using an OS transistor as transistor 233, stable operation and high reliability can be obtained even when driven at high voltages.

[0116] By connecting the selection transistor to the conductive layer 617 used as a wiring RBL, any wiring RBL can be selected to read the data held by the storage element 100A or storage element 100B connected to the selected wiring RBL. Figure 4A An example cross-sectional structure of a memory element in which the conductive layer 617 is electrically connected to the transistor 235 is shown. Additionally, Figure 4B An equivalent circuit diagram corresponding to this cross-sectional structure example is shown.

[0117] exist Figure 4AIn this configuration, conductive layer 617 is electrically connected to conductive layer 161c. Specifically, conductive layer 617 is electrically connected to conductive layer 161c via conductive layers 632, 631, and 168c. Conductive layer 161c is used as one of the source and drain electrodes of transistor 235. Furthermore, conductive layer 155c is used as the other of the source and drain electrodes of transistor 235. Conductive layer 161c and conductive layer 161a can be formed simultaneously using the same material and the same manufacturing process. Conductive layer 155c and conductive layer 155a can be formed simultaneously using the same material and the same manufacturing process. Conductive layer 165c is used as the gate electrode of transistor 235. Conductive layer 165c and conductive layer 165a can be formed simultaneously using the same material and the same manufacturing process. Opening 162c can be formed in the same way as opening 162a. Semiconductor layer 163c and semiconductor layer 163a can be formed simultaneously using the same material and the same manufacturing process. Transistor 235 and transistor 233 can be formed simultaneously using the same materials and the same manufacturing process.

[0118] Note that in this specification, conductive layers 155a, 155b, and 155c are sometimes referred to as conductive layer 155. Additionally, conductive layers 161a, 161b, and 161c are sometimes referred to as conductive layer 161. Furthermore, openings 162a, 162b, and 162c are sometimes referred to as opening 162. Also, semiconductor layers 163a, 163b, and 163c are sometimes referred to as semiconductor layer 163.

[0119] A conductive layer 631 is included on insulating layer 167. Conductive layer 631 and conductive layer 610 can be formed simultaneously using the same material and the same manufacturing process. Conductive layer 632 is disposed through insulating layers 615 and 614. Conductive layer 632 and conductive layer 616 can be formed simultaneously using the same material and the same manufacturing process. Conductive layer 168c is disposed through insulating layers 167, 166, and 164. Conductive layer 168c and conductive layer 168a can be formed simultaneously using the same material and the same manufacturing process.

[0120] <Example 2 of a variation of a storage element>

[0121] Figure 5A and Figure 5B An example of the structure of storage element 100C is shown. Storage element 100C is a modified example of storage element 100A. Figure 5A This is a plan view of storage element 100C. Additionally, Figure 5B It is along Figure 5AThe cross-sectional view of the section marked with dashed lines A1-A2. To avoid repetition, the main differences from storage element 100A will be explained.

[0122] The memory element 100C has a structure in which a portion of the conductive layer 610 is used as one of the source and drain electrodes of the transistor 233, and another portion of the conductive layer 610 is used as one of the source and drain electrodes of the transistor 234. Specifically, the region of the conductive layer 610 that contacts the semiconductor layer 163a is used as one of the source and drain electrodes of the transistor 233. Additionally, the region of the conductive layer 610 that contacts the semiconductor layer 163b is used as one of the source and drain electrodes of the transistor 234.

[0123] By using conductive layer 610 not only as a layer that induces the spin Hall effect, but also as a source or drain electrode of the transistor, it is unnecessary to form conductive layers 161a and 161b. Therefore, the productivity of the memory element 100C is improved, and the manufacturing cost is reduced. Consequently, the productivity of semiconductor devices including the memory element 100C is improved, and the manufacturing cost is reduced.

[0124] Note that in the structure of the memory element 100C, the region of the conductive layer 610 that serves as one of the source and drain electrodes of the transistor 233 is used as a first region 611. Additionally, in the structure of the memory element 100C, the region of the conductive layer 610 that serves as one of the source and drain electrodes of the transistor 234 is used as a second region 612.

[0125] In addition, Figure 5A and Figure 5B In the structure of the storage element 100C shown, apart from conductive layers 161a and 161b, it is not necessary to form insulating layers 166, 167, 168a, 168b, and 164. Therefore, the productivity of the storage element 100C can be further improved.

[0126] In addition, Figure 5A and Figure 5B In the structure of the storage element 100C shown, a portion of the insulating layer 614 is used as the gate insulating layer of the transistor 233, and another portion of the insulating layer 614 is used as the gate insulating layer of the transistor 234.

[0127] Furthermore, the storage element 100C includes a conductive layer 618a that penetrates the insulating layer 615 in the region overlapping with the conductive layer 165a when viewed from the Z direction. Similarly, the storage element 100C includes a conductive layer 618b that penetrates the insulating layer 615 in the region overlapping with the conductive layer 165b when viewed from the Z direction. The conductive layers 618 (conductive layers 618a and 618b) and conductive layer 616 can be formed simultaneously using the same material and the same manufacturing process. Therefore, no new manufacturing process is required to form the conductive layer 618. Like the conductive layer 616, the conductive layer 618 is also used as a contact plug.

[0128] Furthermore, a conductive layer 619 is included on the insulating layer 615, conductive layer 618a, and conductive layer 618b. The conductive layer 619 and the conductive layer 617 can be formed simultaneously using the same material and the same manufacturing process. Therefore, no new manufacturing process is required to form the conductive layer 619.

[0129] In storage elements 100A and 100B, when viewed from the Z-direction, transistor 233, variable resistor 600, and transistor 234 are all arranged in a straight line; however, transistor 233, variable resistor 600, and transistor 234 may not be arranged in a straight line. In storage element 100C, when viewed from the Z-direction, the conductive layer 610 has a curved portion. Figure 5A In the storage element 100C, when viewed from the Z direction, the conductive layer 610 has a U-shaped form. In the storage element 100C, transistors 233 and 234, when viewed from the Z direction, both have regions overlapping with the conductive layer 619. Additionally, the variable resistor element 600 has a region overlapping with the conductive layer 617.

[0130] In the storage element 100C, when viewed from the Z direction, conductive layers 165a and 165b do not overlap with conductive layer 617. Therefore, the parasitic capacitance between conductive layers 617 and 165a, and between conductive layers 617 and 165b, is reduced. This reduction in parasitic capacitance also reduces power consumption. Furthermore, the signal delay time is shortened, thereby improving operating speed.

[0131] In addition, such as Figure 6A and Figure 6B As shown, the formation of conductive layer 619, conductive layer 618a and conductive layer 618b can also be omitted. Figure 6A Is with Figure 5A Plan view of different storage elements 100C. Additionally, Figure 6B It is along Figure 6A A cross-sectional view of the section with the dotted lines A1-A2 in the figure.

[0132] In addition to a reduced footprint, the number of manufacturing steps in the memory element 100C is also reduced. Therefore, the productivity of the memory element 100C is improved, and the manufacturing cost is reduced. Consequently, the productivity of semiconductor devices including the memory element 100C is improved, and the manufacturing cost is reduced.

[0133] In addition, the storage element 100C can also be adopted as follows: Figure 3A and Figure 3B The storage element 100B shown does not have one of transistors 233 and 234.

[0134] <Example 3 of a variation of a storage element>

[0135] Figure 7A and Figure 7B A structural example of storage element 100D is shown. Storage element 100D is a modified example of storage element 100A. Figure 7A This is a plan view of storage element 100D. Additionally, Figure 7B It is along Figure 7A The cross-sectional view is shown in the dashed-dot line A1-A2. To avoid repetition, the main differences from storage element 100A will be explained.

[0136] Transistors 233 and 234 can also be disposed on the upper layer of the variable resistance element 600. The storage element 100D includes transistors 233 and 234 on the variable resistance element 600. Specifically, the storage element 100D includes an insulating layer 154 on the insulating layer 615. Additionally, conductive layers 617, 155a, and 155b are included on the insulating layer 154. In the structure of the storage element 100D, the same material as the conductive layer 617 can be used, and the conductive layers 155a and 155b can be formed simultaneously using the same process.

[0137] In addition, the storage element 100D includes an insulating layer 157 on the insulating layer 154, conductive layer 155a, conductive layer 155b and conductive layer 617.

[0138] Furthermore, in the storage element 100D, conductive layers 618a and 618b are disposed such that they pass through insulating layers 614, 615, and 154. In the storage element 100D, conductive layer 155a is electrically connected to conductive layer 610 via conductive layer 618a. Additionally, conductive layer 155b is electrically connected to conductive layer 610 via conductive layer 618b. Conductive layer 618a is electrically connected to a first region 611 of conductive layer 610, and conductive layer 618b is electrically connected to a second region 612 of conductive layer 610.

[0139] In the memory element 100D, conductive layer 155a can be referred to as one of the source and drain electrodes of transistor 233. Similarly, conductive layer 161a can be referred to as the other of the source and drain electrodes of transistor 233. Likewise, in the memory element 100D, conductive layer 155b can be referred to as one of the source and drain electrodes of transistor 234. Similarly, conductive layer 161b can be referred to as the other of the source and drain electrodes of transistor 234.

[0140] In the structure of memory element 100D, the same material as conductive layer 617 and conductive layer 155a and conductive layer 155b can be formed simultaneously in the same process, thus reducing the number of manufacturing steps compared to memory element 100A. Therefore, the productivity of memory element 100D is improved, and the manufacturing cost is reduced. Consequently, the productivity of semiconductor devices including memory element 100D is improved, and the manufacturing cost is reduced.

[0141] By connecting the selection transistor to the conductive layer 617 used as a wiring RBL, any wiring RBL can be selected and the data held by the storage element 100D connected to the selected wiring RBL can be read. Figure 8A An example of a cross-sectional structure of a memory element 100D is shown, in which the conductive layer 617 is electrically connected to the transistor 235. Additionally, Figure 8B An equivalent circuit diagram corresponding to this cross-sectional structure example is shown.

[0142] exist Figure 8A In the memory element 100D, the conductive layer 617 is electrically connected to the conductive layer 155c. Similar to transistors 233 and 234 described above, in the memory element 100D, the conductive layer 155c can be referred to as one of the source and drain electrodes of transistor 235. Additionally, the conductive layer 161c can be referred to as the other of the source and drain electrodes of transistor 235.

[0143] In addition, the storage element 100D can also adopt, for example Figure 3A and Figure 3B The storage element 100B shown does not have one of transistors 233 and 234.

[0144] <Example 4 of a variation of a storage element>

[0145] Transistor 233, transistor 234 and variable resistor 600 can also be placed on the same layer. Figure 9A and Figure 9B An example of the structure of storage element 100E is shown. Figure 9A and Figure 9B In the storage element 100E shown, transistors 233 and 234 and a variable resistor element 600 are disposed on the insulating layer 154.

[0146] Figure 9A and Figure 9B The storage element 100E shown is a modified example of storage element 100A. Furthermore, storage element 100E is a modified example of storage element 100C and also a modified example of storage element 100D. Figure 9A This is a plan view of storage element 100E. Additionally, Figure 9B It is along Figure 9A The cross-sectional view of the dashed lines A1-A2 in the diagram. To avoid repetition, the main differences from storage element 100A, storage element 100C, or storage element 100D will be explained.

[0147] The memory element 100E has a structure in which a portion of the conductive layer 610 is used as one of the source and drain electrodes of the transistor 233, and another portion of the conductive layer 610 is used as one of the source and drain electrodes of the transistor 234. Specifically, in the memory element 100E, the region of the conductive layer 610 in contact with the semiconductor layer 163a is used as one of the source and drain electrodes of the transistor 233. Additionally, in the memory element 100E, the region of the conductive layer 610 in contact with the semiconductor layer 163b is used as one of the source and drain electrodes of the transistor 234.

[0148] Similar to memory element 100D, in memory element 100E, conductive layer 161a can also be referred to as the other of the source and drain electrodes of transistor 233. Additionally, conductive layer 161b can be referred to as the other of the source and drain electrodes of transistor 234.

[0149] By using conductive layer 610 not only as a layer that induces the spin Hall effect, but also as a source or drain electrode of the transistor, it is unnecessary to form conductive layers 155a and 155b. This improves the productivity of the memory element 100E.

[0150] The storage element 100E includes a conductive layer 610 on an insulating layer 154, and an MTJ element 620 on the conductive layer 610. Additionally, an insulating layer 158 is included on the insulating layer 154, the MTJ element 620, and the insulating layer 614. Figure 9A and Figure 9B In the structure shown, insulating layer 158 and insulating layer 614 are equivalent to insulating layer 156. Note that although in Figure 9A and Figure 9B The storage element 100E shown does not have insulating layers 157 and 159, but insulating layers 157 and 159 can be provided in the same way as other illustrated storage elements. Alternatively, insulating layer 157 can be provided instead of insulating layer 614.

[0151] in addition, Figure 9A and Figure 9B The storage element 100E shown, in the region overlapping with the MTJ element 620 when viewed from the Z direction, includes a conductive layer 168 that passes through insulating layers 167, 166, 164, 158, and 614. Furthermore, a conductive layer 617 is included on insulating layer 167. The conductive layer 617 is electrically connected to the MTJ element 620 through the conductive layer 168.

[0152] In addition, Figure 9A and Figure 9B In the storage element 100E shown, the region of the conductive layer 610 that overlaps with the opening 162a when viewed from the Z direction is used as the first region 611. In the first region 611, the conductive layer 610 is connected to the semiconductor layer 163a. ​​Therefore, the first region 611 of the conductive layer 610 corresponds to the aforementioned conductive layer 155a.

[0153] In addition, Figure 9A and Figure 9B In the storage element 100E shown, the region of the conductive layer 610 that overlaps with the opening 162b when viewed from the Z direction is used as the second region 612. In the second region 612, the conductive layer 610 is connected to the semiconductor layer 163b. Therefore, the second region 612 of the conductive layer 610 corresponds to the aforementioned conductive layer 155b.

[0154] In addition, Figure 9A and Figure 9B In the structure of the shown memory element 100E, apart from conductive layers 155a and 155b, there is no need to form insulating layers 615, conductive layers 616, and conductive layers 619. Therefore, the productivity of the memory element 100E is further improved, and the manufacturing cost is further reduced. Thus, the productivity of semiconductor devices including the memory element 100E is further improved, and the manufacturing cost is further reduced.

[0155] Alternatively, in the aforementioned storage element 100A or storage element 100B, a transistor 236 electrically connected to the conductive layer 617 may be disposed on the upper layer of the variable resistor element 600. As an example, Figure 10 An example of a cross-sectional structure is shown where a transistor 236 is disposed on a storage element 100A or a storage element 100B.

[0156] exist Figure 10In the conductive layer 617, insulating layers 257, 258, and 259 are disposed, and a conductive layer 261c is disposed on the insulating layer 259. Note that insulating layers 257, 258, and 259 are sometimes collectively referred to as insulating layer 256 or spacer layer. Furthermore, in a region that partially overlaps with the conductive layer 617 when viewed from the Z direction, an opening 262c is included in the conductive layer 261c, insulating layer 259, insulating layer 258, and insulating layer 257. Additionally, a semiconductor layer 263c covering the opening 262c is included.

[0157] Additionally, an insulating layer 264 is included on the insulating layer 259, the conductive layer 261c, and the semiconductor layer 263c. Furthermore, a conductive layer 265c is included on the insulating layer 264. The conductive layer 265c has a region overlapping with the opening 262c, and in this region, it has regions that overlap with the side and bottom of the opening 262c across the insulating layer 264 and the semiconductor layer 263c. Furthermore, an insulating layer 266 is included on the insulating layer 264. Furthermore, it is preferable that the top surfaces (positions in the Z direction) of the conductive layer 265c and the insulating layer 266 are aligned or substantially aligned. Furthermore, in Figure 10 In the conductive layer 265c and the insulating layer 266, an insulating layer 267 is included.

[0158] Transistor 236 has the same function as transistor 235. Therefore, insulating layer 257 is equivalent to insulating layer 157, insulating layer 258 is equivalent to insulating layer 158, insulating layer 259 is equivalent to insulating layer 159, and insulating layer 256 is equivalent to insulating layer 156. Additionally, conductive layer 261c is equivalent to conductive layer 161c, and opening 262c is equivalent to opening 162c. Furthermore, semiconductor layer 263c is equivalent to semiconductor layer 163c, insulating layer 264 is equivalent to insulating layer 164, and conductive layer 265c is equivalent to conductive layer 165c. Additionally, insulating layer 266 is equivalent to insulating layer 166, and insulating layer 267 is equivalent to insulating layer 167. Therefore, like transistors 233 and 234, transistor 236 can also be a vertical transistor.

[0159] In transistor 236, a portion of conductive layer 617 is used as one of the source and drain electrodes of transistor 236. More specifically, the region of conductive layer 617 that contacts semiconductor layer 263c is used as one of the source and drain electrodes of transistor 236. Additionally, conductive layer 261c is used as the other of the source and drain electrodes of transistor 236. Furthermore, conductive layer 265c is used as the gate electrode of transistor 236.

[0160] Because transistors 233 to 236 are thin-film transistors, they can be disposed on the same layer or on different layers. For example, transistor 236 can be disposed on top of transistor 233. Therefore, the design freedom of memory elements can be increased. In addition, the design freedom of semiconductor devices can be increased.

[0161] In addition, the storage element 100E can also adopt, for example Figure 3A and Figure 3B The storage element 100B shown has a structure that does not include one of transistors 233 and 234.

[0162] <Example 5 of a variation of a storage element>

[0163] Figure 11A and Figure 11B A structural example of storage element 100F is shown. Storage element 100F is a modified example of storage element 100A. Figure 11A This is a plan view of storage element 100F. Additionally, Figure 11B It is along Figure 11A The cross-sectional view shows the portion indicated by the dashed lines A1-A2. To avoid repetition, the main differences from display element 100A will be explained.

[0164] Storage element 100F includes transistor 333 instead of transistor 233, and includes transistor 334 instead of transistor 234. Transistors 333 and 334 are also the same vertical transistors as transistors 233 and 234.

[0165] In transistor 233, a portion of the conductive layer 165a, which serves as the gate electrode, is disposed inside the opening 162a. Conversely, in transistor 333, when viewed from the Z direction, the conductive layer 175a, which serves as the gate electrode, is disposed outside the opening 162a. Furthermore, in transistor 234, a portion of the conductive layer 165b, which serves as the gate electrode, is disposed inside the opening 162b. Conversely, in transistor 334, when viewed from the Z direction, the conductive layer 175b, which serves as the gate electrode, is disposed outside the opening 162b.

[0166] In the structures shown by transistors 233 and 234, when the width of the opening 162 (or diameter when the opening 162 is circular) viewed from the Z direction is reduced to achieve miniaturization of the memory element, the conductive layer 165 used as the gate electrode is not easily formed inside the opening 162. In the structures shown by transistors 333 and 334, the conductive layer 175 used as the gate electrode is located outside the opening 162, so the aforementioned concern is not present. Therefore, it is easy to achieve miniaturization and reduction of the area of ​​the memory element, thereby increasing design freedom. In addition, the storage density of memory devices using memory elements according to one aspect of the present invention can be further increased.

[0167] exist Figure 11A and Figure 11B In the storage element 100F shown, conductive layers 175a and 175b are included on the insulating layer 157, an insulating layer 159 is included on the conductive layers 175a and 175b, and conductive layers 161a and 161b are included on the insulating layer 159.

[0168] Additionally, the region overlapping with conductive layer 155a includes an opening 162a that passes through conductive layer 161a, insulating layer 159, conductive layer 175a, and insulating layer 157. The opening 162a includes an insulating layer 181a having a region overlapping with the side surface of the opening 162a. The insulating layer 181a has regions overlapping with the side surface of conductive layer 161a, regions overlapping with the side surface of insulating layer 159, regions overlapping with the side surface of conductive layer 175a, and regions overlapping with the side surface of insulating layer 157.

[0169] Additionally, a semiconductor layer 163a is included covering the opening 162a. In the opening 162a, the semiconductor layer 163a has a region overlapping the side of the insulating layer 159 separated by the insulating layer 181a, a region overlapping the side of the conductive layer 175a, and a region overlapping the side of the insulating layer 157. Furthermore, the semiconductor layer 163a has a region in contact with the conductive layer 155a and a region in contact with the conductive layer 161a. The insulating layer 181a serves as the gate insulating layer of the transistor 333, and the conductive layer 175a serves as the gate electrode of the transistor 333.

[0170] Additionally, the region overlapping with conductive layer 155b includes an opening 162b that passes through conductive layer 161b, insulating layer 159, conductive layer 175b, and insulating layer 157. The opening 162b includes an insulating layer 181b having a region overlapping with the side surface of the opening 162b. The insulating layer 181b has regions overlapping with the side surface of conductive layer 161b, regions overlapping with the side surface of insulating layer 159, regions overlapping with the side surface of conductive layer 175b, and regions overlapping with the side surface of insulating layer 157.

[0171] Additionally, a semiconductor layer 163b covering the opening 162b is included. In the opening 162b, the semiconductor layer 163b has regions overlapping with the side of the insulating layer 159, separated by the insulating layer 181b, overlapping with the side of the conductive layer 175b, and overlapping with the side of the insulating layer 157. Furthermore, the semiconductor layer 163b has regions contacting the conductive layer 155b and regions contacting the conductive layer 161b. The insulating layer 181b serves as the gate insulating layer of the transistor 334, and the conductive layer 175b serves as the gate electrode of the transistor 334.

[0172] Furthermore, in the storage element 100F, conductive layer 175 and conductive layer 617 extend in the X direction. A portion of conductive layer 175 is used as conductive layer 175a, and another portion of conductive layer 175 is used as conductive layer 175b. Conductive layer 175 is used as wiring WL. As described above, wiring WL preferably intersects with at least one of wiring WBLa and wiring WBLb.

[0173] Alternatively, the storage element 100F can also employ, for example... Figure 3A and Figure 3B The storage element 100B shown does not have one of transistors 333 and 334.

[0174] <Example 6 of a variation of a storage element>

[0175] Figure 12A and Figure 12B A structural example of storage element 100G is shown. Storage element 100G is a modified example of storage element 100C and also a modified example of storage element 100F. Figure 12A This is a plan view of a 100G storage element. Figure 12B It is along Figure 12A The cross-sectional view shows the portion indicated by the dashed lines A1-A2. To avoid repetition, the differences from storage element 100C or storage element 100F will be mainly explained.

[0176] Similar to memory element 100C, memory element 100G has a structure in which a portion of conductive layer 610 is used as one of the source and drain electrodes of transistor 333, and another portion of conductive layer 610 is used as one of the source and drain electrodes of transistor 334. By using conductive layer 610 not only as a layer inducing the spin Hall effect, but also as a source or drain electrode of the transistor, it is unnecessary to form conductive layers 161a and 161b. Therefore, the productivity of memory element 100G is improved, and the manufacturing cost is reduced. Consequently, the productivity of semiconductor devices including memory element 100G is improved, and the manufacturing cost is reduced.

[0177] In addition, the 100G storage element can also be adopted as follows: Figure 3A and Figure 3B The storage element 100B shown does not have one of transistors 333 and 334.

[0178] In addition, similar to the structural example shown in Figure 4, by connecting the selection transistor to the conductive layer 617 used as the wiring RBL, any wiring RBL can be selected and the data held by the storage element 100G connected to the selected wiring RBL can be read. Figure 13A An example cross-sectional structure of a memory element in which the conductive layer 617 is electrically connected to the transistor 335 is shown. Additionally, Figure 13B An equivalent circuit diagram corresponding to this cross-sectional structure example is shown.

[0179] Note that, to avoid repetition, only the parts that differ from those already described will be explained. For an explanation of Figure 13, please refer to the explanation of Figure 4, etc. Transistor 335 can be formed simultaneously using the same material and process as transistor 333 shown in the structure of storage element 100F. The conductive layer 175c of transistor 335 can be formed simultaneously using the same material and process as conductive layer 175a of transistor 333. The opening 162c of transistor 335 can be formed in the same manner as opening 162a of transistor 333. The insulating layer 181c of transistor 335 can be formed simultaneously using the same material and process as insulating layer 181a of transistor 333. Note that in this specification, insulating layers 181a, 181b, and 181c are sometimes referred to as insulating layer 181.

[0180] In addition, with Figure 10 Similarly, in the illustrated structural example, in storage element 100F or storage element 100G, a transistor 336 electrically connected to the conductive layer 617 can also be disposed in the upper layer of the variable resistor element 600. As an example, Figure 14 An example cross-sectional structure of a transistor 336 disposed on a storage element 100F is shown. The transistor 336 is electrically connected to a variable resistor element 600 via a conductive layer 617. Note that, to avoid repetition, only the parts whose configuration differs from that already described are explained. Regarding... Figure 14 For further explanation, please refer to the relevant information. Figure 10 The explanation is sufficient.

[0181] exist Figure 14In the conductive layer 617, insulating layers 257 and 259 are disposed, and insulating layer 259 includes a conductive layer 261c. Furthermore, in a region that partially overlaps with the conductive layer 617 when viewed from the Z direction, an opening 262c is included in the conductive layer 261c, insulating layer 259, conductive layer 275c, and insulating layer 257. Additionally, a semiconductor layer 263c covering the opening 262c is included.

[0182] The opening 262c includes an insulating layer 281c having regions overlapping with the sides of the opening 262c. The insulating layer 281c has regions overlapping with the sides of the conductive layer 261c, the insulating layer 259, the conductive layer 275c, and the insulating layer 257. The conductive layer 275c corresponds to the conductive layer 175c in the transistor 335.

[0183] Furthermore, an insulating layer 264 is included on the insulating layer 259, the conductive layer 261c, and the semiconductor layer 263c. Additionally, an insulating layer 266 is included on the insulating layer 264. Note that the surface of the insulating layer 266 is preferably flat. The transistor 336 has the same function as the transistor 335.

[0184] exist Figure 14 In the transistor 336 shown, a portion of the conductive layer 617 is used as one of the source and drain electrodes. More specifically, the region of the conductive layer 617 that contacts the semiconductor layer 263c is used as one of the source and drain electrodes of the transistor 336. Furthermore, the conductive layer 261c is used as the other of the source or drain electrodes. Additionally, the conductive layer 275c is used as the gate electrode of the transistor 336.

[0185] Because transistors 333 to 336 are thin-film transistors, they can be disposed on the same layer or on different layers. For example, transistor 336 can be disposed on top of transistor 333. Therefore, the design freedom of memory elements can be increased. Additionally, the design freedom of semiconductor devices can be increased.

[0186] In addition, such as Figure 15 As shown, transistor 236 can also be used instead of transistor 336. For example, to accelerate the potential change of the conductive layer 617 used as the wiring RBL, when it is desired to use a transistor with a large on-state current connected to the conductive layer 617, transistor 236 can be used as the conductive layer 617. By using transistor 333 as the transistor connected to the conductive layer 610 and transistor 236 as the transistor connected to the conductive layer 617, a storage device with high storage density and high operating speed can be realized.

[0187] Note that the transistors connected to the conductive layer 617 are not limited to vertical transistors. Various transistor structures can be used as transistors connected to the conductive layer 617, such as top-gate type (e.g., planar and interleaved types), bottom-gate type (e.g., anti-planar and anti-interleaved types), dual-gate type (a structure in which gates are arranged on both sides (e.g., top and bottom) sandwiching the channel formation region), FIN type, and TRI-GATE type.

[0188] Alternatively, the transistor connected to conductive layer 617 can also be a transistor of a different conductivity type than transistors 233 and 234.

[0189] <transistor>

[0190] Conductive layer 161a is used as one of the source and drain electrodes of transistor 233. Furthermore, conductive layer 155a is used as the other of the source and drain electrodes of transistor 233. Additionally, semiconductor layer 163a is used as the semiconductor layer of transistor 233. Furthermore, insulating layer 164 is used as the gate insulating layer of transistor 233, and conductive layer 165a is used as the gate electrode of transistor 233.

[0191] Conductive layer 161b is used as one of the source and drain electrodes of transistor 234. Conductive layer 155b is used as the other of the source and drain electrodes of transistor 234. Semiconductor layer 163b is used as the semiconductor layer of transistor 234. Insulating layer 164 is used as the gate insulating layer of transistor 234, and conductive layer 165b is used as the gate electrode of transistor 234.

[0192] Figure 1A and Figure 1B Transistors 233 and 234 shown are transistors with their source and drain electrodes positioned in the Z-direction. That is, the source and drain of transistors 233 and 234 are positioned at different heights. In other words, the source and drain of transistors 233 and 234 are located at different positions in the Z-direction. This type of transistor is sometimes also called a "vertical channel transistor," "vertical type transistor," "vertical transistor," or "VFET (Vertical Field Effect Transistor)."

[0193] Alternatively, vertical transistors can be used in transistors 235 and 236 shown in this specification. Vertical transistors can also be used in transistors 333 to 336 shown in this specification. Compared to conventional transistors (e.g., planar transistors) where channel formation regions, source regions, and drain regions are respectively provided on the XY plane, vertical transistors can reduce the occupied area. Therefore, by using vertical channel transistors, the occupied area of ​​memory elements 100 (memory elements 100A to 100G) can be reduced. Therefore, the occupied area of ​​the memory device including memory element 100 can be reduced. Furthermore, the storage density of the memory device including memory element 100 can be increased. Furthermore, the storage capacity per unit area of ​​the semiconductor device using memory element 100 can be increased. Furthermore, by using vertical channel transistors in semiconductor devices, miniaturization and high integration of the semiconductor device can be achieved.

[0194] Furthermore, the channel length of existing transistors is limited by the exposure limits of photolithography. In vertical channel transistors, the channel formation region is formed along the side of insulating layer 156 or insulating layer 158. Therefore, the channel length can be set according to the thickness of insulating layer 156 or insulating layer 158. This allows for the setting of the transistor's channel length to achieve very fine structures below the exposure limits of photolithography (e.g., 1 nm or more and 60 nm or less, 1 nm or more and 50 nm or less, 1 nm or more and 40 nm or less, 1 nm or more and 30 nm or less, 1 nm or more and 20 nm or less, or 1 nm or more and 10 nm or less). This increases the on-state current of transistors 233 and 234, thereby improving frequency characteristics. Vertical transistors have a structure that facilitates reducing channel length and easily increases on-state current (reducing on-state resistance). By employing vertical channel transistors, a semiconductor device with high operating speed can be provided.

[0195] Transistors 233 to 236 and 333 to 336 can be either n-channel or p-channel transistors. Because the on-state current of an n-channel transistor is larger than that of a p-channel transistor, it can improve data write and read speeds. Furthermore, compared to n-channel transistors, p-channel transistors are easier to implement as normally-off transistors (transistors that are off when the voltage between the source and gate is 0V), thus making it easier to control the transistor's operating state (on or off). This results in more stable operation of the semiconductor device and improves its reliability.

[0196] Furthermore, since transistors 233 and 234 switch operating states simultaneously, it is preferable that they are transistors of the same conductivity type. By making transistors 233 and 234 transistors of the same conductivity type, both transistors can be controlled by a single wiring, thus reducing the area occupied by the storage element according to one aspect of the present invention. For the same reason, transistors 333 and 334 are also preferably transistors of the same conductivity type.

[0197] <Constructing Materials>

[0198] Here, an example of a material that can be used in a storage element and a semiconductor device including a storage element according to one aspect of the present invention is described.

[0199] [Substrate]

[0200] When mounting memory elements and semiconductor devices including memory elements on a substrate, there are no particular restrictions on the material used for the substrate. The choice of material depends on factors such as the presence or absence of light transmittance and the heat resistance to withstand heat treatment. Examples of substrates that can be used include insulating substrates, semiconductor substrates, and conductive substrates. Examples of insulating substrates include glass substrates such as barium borosilicate glass and aluminum borosilicate glass, ceramic substrates, quartz substrates, sapphire substrates, and stabilized zirconia substrates (yttrium-stabilized zirconia substrates, etc.). Furthermore, semiconductor substrates, flexible substrates, and resin substrates can also be used.

[0201] For example, semiconductor substrates can be made of silicon or germanium, or compound semiconductor substrates using silicon carbide, silicon germanium, gallium arsenide, indium phosphide, zinc oxide, or gallium oxide as their materials. Furthermore, semiconductor substrates having insulating regions within the aforementioned semiconductor substrates can also be included, such as SOI (Silicon On Insulator) substrates. In addition, the semiconductor substrate can be a single-crystal semiconductor or a polycrystalline semiconductor.

[0202] Examples of conductive substrates include graphite substrates, metal substrates, alloy substrates, and conductive resin substrates. Alternatively, examples include substrates containing metal nitrides and substrates containing metal oxides. Furthermore, examples include insulating substrates with conductive or semiconductor layers, semiconductor substrates with conductive or insulating layers, and conductive substrates with semiconductor or insulating layers.

[0203] Materials that can be used as flexible substrates, resin substrates, etc. include, for example, polyesters such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), polyacrylonitrile, acrylic resins, polyimide, polymethyl methacrylate, polycarbonate (PC), polyethersulfone (PES), polyamides (nylon, aromatic polyamides, etc.), polysiloxanes, cycloolefin resins, polystyrene, polyamide-imide, polyurethane, polyvinyl chloride, polyvinylidene chloride, polypropylene, polytetrafluoroethylene (PTFE), ABS resin, and cellulose nanofibers, etc.

[0204] By using the above-mentioned materials as substrates, lightweight semiconductor devices can be provided. Furthermore, by using the above-mentioned materials as substrates, semiconductor devices with high impact resistance can be provided. Additionally, by using the above-mentioned materials as substrates, semiconductor devices that are not easily broken can be provided.

[0205] Alternatively, substrates on which components are disposed can be used. Examples of components disposed on the substrate include capacitors, resistors, switching elements, light-emitting elements, and storage elements.

[0206] [Insulating layer]

[0207] As an insulating layer, insulating oxides, nitrides, oxynitrides, oxynitrides, metal oxides, metal oxynitrides, and metal oxynitrides can be used. For example, a single layer or stack of insulating materials selected from the following can be used as the insulating layer: aluminum nitride, aluminum oxide, aluminum oxynitride, aluminum oxynitride, magnesium oxide, silicon nitride, silicon oxide, silicon oxynitride, silicon oxynitride, gallium oxide, germanium oxide, yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, hafnium oxide, tantalum oxide, aluminosilicates, etc. Alternatively, multiple materials selected from oxides, nitrides, oxynitrides, and oxynitrides can also be used.

[0208] In this specification, nitrogen oxides refer to materials with a nitrogen content greater than their oxygen content. Similarly, oxynitrides refer to materials with an oxygen content greater than their nitrogen content. Furthermore, the content of each element can be measured using methods such as Rutherford backscattering spectrometry (RBS).

[0209] When miniaturizing and highly integrating transistors, problems such as leakage current sometimes occur due to the thinning of the gate insulating layer. By using a high-k material (a material with a high relative permittivity) as the insulating layer used as the gate insulating layer, the gate potential during transistor operation can be reduced while maintaining the physical thickness. Furthermore, materials with high permittivity, such as lead zirconate titanate (PZT), strontium titanate (SrTiO3), and (Ba,Sr)TiO3 (BST), can sometimes be used as the insulating layer. On the other hand, by using a material with a relatively low permittivity as the insulating layer used as the interlayer film, parasitic capacitance generated between wirings can be reduced. Therefore, it is preferable to select the material according to the required function of the insulating layer.

[0210] In addition, materials with relatively high permittivity include gallium oxide, hafnium oxide, zirconium oxide, oxides containing aluminum and hafnium, oxynitrides containing aluminum and hafnium, oxides containing silicon and hafnium, oxynitrides containing silicon and hafnium, and nitrides containing silicon and hafnium.

[0211] In addition, examples of materials with relatively low permittivity include silicon oxide, silicon oxynitride, silicon oxynitride, silicon nitride, silicon oxide with added fluorine, silicon oxide with added carbon, silicon oxide with added carbon and nitrogen, porous silicon oxide, and resins.

[0212] There are no particular restrictions on the formation method of insulating materials. Various formation methods can be used, such as vapor deposition, atomic layer deposition (ALD), chemical vapor deposition (CVD), sputtering, spin coating, etc.

[0213] For example, insulating layers 154 and 167 are preferably formed using insulating materials that do not readily allow impurities to pass through. For example, single layers or stacks of insulating materials containing boron, carbon, nitrogen, oxygen, fluorine, magnesium, aluminum, silicon, phosphorus, chlorine, argon, gallium, germanium, yttrium, zirconium, lanthanum, neodymium, hafnium, or tantalum can be used. Examples of insulating materials that do not readily allow impurities to pass through include aluminum oxide, aluminum nitride, aluminum oxynitride, aluminum oxynitride, gallium oxide, germanium oxide, yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, hafnium oxide, tantalum oxide, and silicon nitride.

[0214] By using an insulating material that does not easily allow impurities to pass through as insulating layer 154, the diffusion of impurities from below insulating layer 154 can be suppressed, thereby improving the reliability of the transistor. In other words, the reliability of the semiconductor device including the transistor can be improved. Similarly, by using an insulating material that does not easily allow impurities to pass through as insulating layer 167, the diffusion of impurities from above insulating layer 167 can be suppressed, thereby improving the reliability of the transistor. In other words, the reliability of the semiconductor device including the transistor can be improved.

[0215] Alternatively, insulating layers used as planarization layers can also be used as insulating layers. Examples of materials used as planarization layers include acrylic resins, polyimides, epoxy resins, polyamides, polyimide amides, silicone resins, benzocyclobutene resins, phenolic resins, and precursors of these resins. In addition to the aforementioned organic materials, low-k materials (materials with low dielectric constants, materials with relatively small dielectric constants), silicone resins, PSG (phosphosilicate glass), and BPSG (borophosphosilicate glass) can also be used. Furthermore, multiple insulating layers formed from these materials can be laminated.

[0216] Siloxane resins are resins containing Si-O-Si bonds formed from siloxane-based materials. Siloxane resins can also use organic groups (e.g., alkyl or aryl) or fluorine groups as substituents. Furthermore, the organic groups can also contain fluorine groups.

[0217] [Conductive layer]

[0218] As a conductive material for conductive layers used in wiring and electrodes, a metallic element selected from aluminum (Al), chromium (Cr), copper (Cu), silver (Ag), gold (Au), platinum (Pt), tantalum (Ta), nickel (Ni), titanium (Ti), molybdenum (Mo), tungsten (W), hafnium (Hf), vanadium (V), niobium (Nb), manganese (Mn), magnesium (Mg), zirconium (Zr), beryllium (Be), ruthenium (Ru), etc., an alloy with the above metallic elements as components, or an alloy combining the above metallic elements can be used.

[0219] For example, tantalum nitride, titanium nitride, tungsten, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, and oxides containing lanthanum and nickel are preferred. Furthermore, tantalum nitride, titanium nitride, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, and oxides containing lanthanum and nickel are conductive materials that are not easily oxidized or maintain conductivity even after absorbing oxygen, and are therefore preferred. In addition, semiconductors with high conductivity, such as polycrystalline silicon containing impurity elements such as phosphorus, and silicides such as nickel silicides can also be used. There are no particular limitations on the formation method of the conductive material; various formation methods such as vapor deposition, ALD, CVD, sputtering, and spin coating can be used.

[0220] Alternatively, Cu-X alloys (where X is Mn, Ni, Cr, Fe, Co, Mo, Ta, or Ti) can be used as conductive materials. Layers formed using Cu-X alloys can be processed using a wet etching process, thereby reducing manufacturing costs. Furthermore, aluminum alloys containing one or more elements selected from titanium, tantalum, tungsten, molybdenum, chromium, neodymium, and scandium can also be used as conductive materials.

[0221] As conductive materials suitable for use in the conductive layer, oxygen-containing conductive materials such as indium tin oxide, indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium zinc oxide, and indium tin oxide with added silicon oxide can also be used. Furthermore, nitrogen-containing conductive materials such as titanium nitride, tantalum nitride, and tungsten nitride can also be used. Additionally, the conductive layer can also be a laminated structure that appropriately combines oxygen-containing conductive materials, nitrogen-containing conductive materials, and materials containing the aforementioned metallic elements.

[0222] For example, the conductive layer can also be a single-layer structure containing an aluminum layer with silicon, a two-layer structure with a titanium layer stacked on an aluminum layer, a two-layer structure with a titanium layer stacked on a titanium nitride layer, a two-layer structure with a tungsten layer stacked on a titanium nitride layer, a two-layer structure with a tungsten layer stacked on a tantalum nitride layer, and a three-layer structure with a titanium layer, an aluminum layer, and a titanium layer stacked sequentially.

[0223] Alternatively, multiple conductive layers formed from the aforementioned conductive materials can be stacked. For example, the conductive layer may also employ a stacked structure combining materials containing the aforementioned metallic elements and conductive materials containing oxygen. Furthermore, the conductive layer may also employ a stacked structure combining materials containing the aforementioned metallic elements, conductive materials containing oxygen, and conductive materials containing nitrogen.

[0224] For example, the conductive layer may also be a three-layer structure consisting of a conductive layer containing at least one of indium and zinc and oxygen, a conductive layer containing copper, and a conductive layer containing at least one of indium and zinc and oxygen, stacked sequentially. In this case, it is preferable that the sides of the conductive layer containing copper are also covered by a conductive layer containing at least one of indium and zinc and oxygen. Alternatively, for example, multiple conductive layers containing at least one of indium and zinc and oxygen may be stacked as the conductive layer.

[0225] [Semiconductor layer]

[0226] As semiconductor layers, single-crystal semiconductors, polycrystalline semiconductors, microcrystalline semiconductors, amorphous semiconductors, etc., can be used individually or in combination. As semiconductor materials, in addition to monomeric semiconductors whose main component is a single element (e.g., silicon or germanium), compound semiconductors (e.g., silicon-germanium, silicon carbide, gallium arsenide, nitride semiconductors, etc.) can also be used. Furthermore, organic materials with semiconductor properties or metal oxides with semiconductor properties (also known as "oxide semiconductors") can be used as compound semiconductors. Note that these semiconductor materials can also contain impurities as dopants.

[0227] For example, monocrystalline silicon, polycrystalline silicon, microcrystalline silicon, and amorphous silicon can also be used as semiconductor layers. For example, low-temperature polycrystalline silicon (LTPS) can also be used as polycrystalline silicon.

[0228] Transistors using amorphous silicon as the semiconductor layer can be formed on large glass substrates, enabling low-cost manufacturing. Transistors using polycrystalline silicon as the semiconductor layer exhibit high field-effect mobility, allowing for high-speed operation. Furthermore, transistors using microcrystalline silicon as the semiconductor layer also exhibit high field-effect mobility, enabling high-speed operation compared to transistors using amorphous silicon.

[0229] Semiconductor layers can also contain layered materials used as semiconductors. Layered materials are a general term for a group of materials with a layered crystalline structure. A layered crystalline structure is a structure in which layers formed by covalent or ionic bonds are stacked together by bonds weaker than covalent and ionic bonds, such as van der Waals forces. Layered materials have high conductivity per unit layer, that is, high two-dimensional conductivity. By using materials that act as semiconductors and have high two-dimensional conductivity in the channel formation region, transistors with large on-state currents can be provided.

[0230] Examples of layered materials mentioned above include graphene, silicene, and chalcogenides. Chalcogenides are compounds containing chalcogen elements (elements belonging to Group 16). Other examples of chalcogenides include transition metal chalcogenides and Group 13 chalcogenides. Transition metal chalcogenides that can be used as semiconductor layers in transistors include molybdenum sulfide (typically MoS2), molybdenum selenide (typically MoSe2), molybdenum telluride (typically MoTe2), tungsten sulfide (typically WS2), tungsten selenide (typically WSe2), tungsten telluride (typically WTe2), hafnium sulfide (typically HfS2), hafnium selenide (typically HfSe2), zirconium sulfide (typically ZrS2), and zirconium selenide (typically ZrSe2).

[0231] Furthermore, oxide semiconductors have a band gap of over 2 eV, resulting in extremely low off-state currents for oxide semiconductor transistors (also known as "OS transistors") within the channel formation region. At room temperature, an OS transistor with a channel width of 1 μm can achieve an off-state current of 1 aA (1 × 10⁻⁶). -18 A) Below, 1zA (1×10 -21 A) or below or 1yA (1×10 -24A) Below. Furthermore, OS transistors operate stably at high temperatures with minimal characteristic variation, resulting in high reliability. For example, even at temperatures above 125°C but below 200°C, the off-state current of an OS transistor hardly increases. Moreover, the on-state current does not easily decrease even at high temperatures. Therefore, good switching operation can be achieved even at high temperatures.

[0232] In addition, OS transistors have high drain voltage. Therefore, semiconductor devices using OS transistors operate stably and reliably even when driven at high voltages.

[0233] Examples of metal oxides used in oxide semiconductors include indium oxide, gallium oxide, and zinc oxide. The metal oxide used in oxide semiconductors preferably contains at least indium (In) or zinc (Zn). Furthermore, the metal oxide used in oxide semiconductors preferably contains two or three elements selected from indium, element M, and zinc. Note that element M is a metallic or half-metallic element with a high bonding energy with oxygen, for example, a metallic or half-metallic element with a higher bonding energy with oxygen than indium.

[0234] Element M can specifically include aluminum, gallium, tin, yttrium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, zirconium, molybdenum, hafnium, tantalum, tungsten, lanthanum, cerium, neodymium, magnesium, calcium, strontium, barium, boron, silicon, germanium, and antimony. The element M included in the metal oxide is preferably any one or more of the above elements, more preferably one or more selected from aluminum, gallium, tin, and yttrium, and even more preferably gallium. Note that in this specification, metallic elements and half-metallic elements are sometimes collectively referred to as "metallic elements," and sometimes the "metallic elements" described in this specification include half-metallic elements.

[0235] For example, as metal oxides used in oxide semiconductors, indium oxide (In oxide), indium zinc oxide (In-Zn oxide), indium tin oxide (In-Sn oxide), indium titanium oxide (In-Ti oxide), indium gallium oxide (In-Ga oxide), indium gallium aluminum oxide (In-Ga-Al oxide), indium gallium tin oxide (In-Ga-Sn oxide), gallium zinc oxide (Ga-Zn oxide, also denoted as "GZO"), and aluminum zinc oxide (Al-Zn oxide, also denoted as "GZO") can be used. Indium aluminum zinc oxide (In-Al-Zn oxide, also known as "IAZO"), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium zinc oxide (In-Ga-Zn oxide, also known as "IGZO"), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide, also known as "IGZTO"), and indium gallium aluminum zinc oxide (In-Ga-Al-Zn oxide, also known as "IGAZO" or "IAGZO") can be used. Alternatively, silicon-containing indium tin oxide, gallium tin oxide (Ga-Sn oxide), and aluminum tin oxide (Al-Sn oxide) can be used.

[0236] The field-effect mobility of an OS transistor can be improved by increasing the ratio of the number of indium atoms contained in the metal oxide used for oxide semiconductors relative to the sum of the number of atoms of all metal elements.

[0237] Note that metal oxides can also contain one or more metals with high period numbers in the periodic table to replace indium. Alternatively, metal oxides can contain one or more metals with high period numbers in the periodic table in addition to indium. The greater the overlap of the metal orbitals in a metal oxide, the greater the carrier conduction. Therefore, by including metals with high period numbers in the periodic table, the field-effect mobility of transistors can sometimes be improved. Examples of metals with high period numbers in the periodic table include metals belonging to period 5, period 6, etc. Specifically, examples of such metals include yttrium, zirconium, silver, cadmium, tin, antimony, barium, lead, bismuth, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, and europium. Note that lanthanum, cerium, praseodymium, neodymium, promethium, samarium, and europium are called light rare earth elements.

[0238] In addition, metal oxides can also contain one or more non-metallic elements. Including non-metallic elements in metal oxides can sometimes improve the field-effect mobility of transistors. Examples of non-metallic elements include carbon, nitrogen, phosphorus, sulfur, selenium, fluorine, chlorine, bromine, and hydrogen.

[0239] By increasing the ratio of zinc atoms to the total number of atoms of the metal elements in the main component elements contained in the metal oxide, a highly crystalline metal oxide is produced, thereby suppressing the diffusion of impurities in the metal oxide. Therefore, variations in the electrical characteristics of the transistor are suppressed, and reliability is improved.

[0240] By increasing the ratio of the number of atoms of element M, which is the main component element contained in the metal oxide relative to the total number of atoms of the metal element, the formation of oxygen vacancies in the metal oxide can be suppressed. Therefore, carrier generation caused by oxygen vacancies is suppressed, thereby enabling transistors with low off-state currents. Furthermore, variations in the electrical characteristics of the transistor are suppressed, thereby improving reliability.

[0241] The electrical characteristics and reliability of transistors vary depending on the composition of the metal oxide used in the semiconductor layer. Therefore, by varying the composition of the metal oxide according to the required electrical characteristics and reliability of the transistor, it is possible to realize semiconductor devices that possess both excellent electrical characteristics and high reliability.

[0242] When using In-Zn oxide as the semiconductor layer of an OS transistor, metal oxides with an indium atomic ratio greater than or equal to that of zinc can also be used. For example, metal oxides with an indium:Zn atomic ratio of 1:1, 2:1, 3:1, 4:1, 5:1, 7:1, 10:1 or similar can also be used.

[0243] When using In-Sn oxide as the semiconductor layer of an OS transistor, metal oxides with an indium atomic ratio greater than or equal to that of tin can also be used. For example, metal oxides with an indium:Sn atomic ratio of 1:1, 2:1, 3:1, 4:1, 5:1, 7:1, 10:1 or similar can also be used.

[0244] When using In-Sn-Zn oxide as the semiconductor layer of an OS transistor, a metal oxide with an indium atomic ratio higher than that of tin can also be used. Furthermore, a metal oxide with a zinc atomic ratio higher than that of tin is preferred. For example, metal oxides with atomic ratios of the metal elements such as In:Sn:Zn=2:1:3, In:Sn:Zn=3:1:2, In:Sn:Zn=4:2:3, In:Sn:Zn=4:2:4.1, In:Sn:Zn=5:1:3, In:Sn:Zn=5:1:6, In:Sn:Zn=5:1:7, In:Sn:Zn=5:1:8, etc., can be used. =6:1:6、In:Sn:Zn=10:1:3、In:Sn:Zn=10:1:6、In:Sn:Zn=10:1:7、In:Sn:Zn=10:1:8、In :Sn:Zn=5:2:5, In:Sn:Zn=10:1:10, In:Sn:Zn=20:1:10, In:Sn:Zn=40:1:10 or metal oxides nearby.

[0245] When using In-Al-Zn oxide as the semiconductor layer of an OS transistor, a metal oxide with an indium atomic ratio higher than that of aluminum can also be used. Furthermore, a metal oxide with a zinc atomic ratio higher than that of aluminum is preferred. For example, metal oxides with atomic ratios of the metal elements such as In:Al:Zn=2:1:3, In:Al:Zn=3:1:2, In:Al:Zn=4:2:3, In:Al:Zn=4:2:4.1, In:Al:Zn=5:1:3, In:Al:Zn=5:1:6, In:Al:Zn=5:1:7, In:Al:Zn=5:1:8, etc., can also be used. Metal oxides of n=6:1:6, In:Al:Zn=10:1:3, In:Al:Zn=10:1:6, In:Al:Zn=10:1:7, In:Al:Zn=10:1:8, In:Al:Zn=5:2:5, In:Al:Zn=10:1:10, In:Al:Zn=20:1:10, In:Al:Zn=40:1:10 or similar.

[0246] When using In-Ga-Zn oxide as the semiconductor layer of an OS transistor, a metal oxide in which the atomic ratio of indium relative to the sum of the atomic numbers of the metal elements is higher than that of gallium can also be used. Furthermore, a metal oxide in which the atomic ratio of zinc is higher than that of gallium is preferred. For example, the semiconductor layer can also use metal oxides with atomic ratios of In:Ga:Zn=2:1:3, In:Ga:Zn=3:1:2, In:Ga:Zn=4:2:3, In:Ga:Zn=4:2:4.1, In:Ga:Zn=5:1:3, In:Ga:Zn=5:1:6, In:Ga:Zn=5:1:7, In:Ga:Zn=5:1:8, etc. Metal oxides of the following types or their vicinity: Zn=6:1:6, In:Ga:Zn=10:1:3, In:Ga:Zn=10:1:6, In:Ga:Zn=10:1:7, In:Ga:Zn=10:1:8, In:Ga:Zn=5:2:5, In:Ga:Zn=10:1:10, In:Ga:Zn=20:1:10, In:Ga:Zn=40:1:10, or similar metal oxides.

[0247] When using In-M-Zn oxide as the semiconductor layer of an OS transistor, a metal oxide in which the atomic ratio of indium relative to the sum of the atomic numbers of the metal elements is higher than the atomic ratio of element M can also be used. Furthermore, a metal oxide in which the atomic ratio of zinc is higher than the atomic ratio of element M is preferred. For example, the semiconductor layer can also use metal oxides with atomic ratios of In:M:Zn=2:1:3, In:M:Zn=3:1:2, In:M:Zn=4:2:3, In:M:Zn=4:2:4.1, In:M:Zn=5:1:3, In:M:Zn=5:1:6, In:M:Zn=5:1:7, In:M:Zn=5:1:8, etc. Metal oxides of Zn=6:1:6, In:M:Zn=10:1:3, In:M:Zn=10:1:6, In:M:Zn=10:1:7, In:M:Zn=10:1:8, In:M:Zn=5:2:5, In:M:Zn=10:1:10, In:M:Zn=20:1:10, In:M:Zn=40:1:10 or similar.

[0248] When using In-M-Zn oxide as the semiconductor layer, the following metal oxides can also be used: compositions with an atomic ratio of In:M:Zn = 1:3:2 or similar, In:M:Zn = 1:3:4 or similar, In:M:Zn = 1:1:0.5 or similar, In:M:Zn = 1:1:1 or similar, In:M:Zn = 1:1:1.2 or similar, In:M:Zn = 1:1:2 or similar, or In:M:Zn = 4:2:3 or similar. Note that "similar" includes a range of ±30% of the desired atomic ratio. Furthermore, gallium is preferably used as element M.

[0249] Note that when element M comprises multiple metallic elements, the total atomic ratio of these metallic elements can be the atomic ratio of element M. For example, when using an In-Ga-Al-Zn oxide comprising gallium and aluminum as element M, the total atomic ratio of gallium and aluminum can be the atomic ratio of element M. Furthermore, the atomic ratio of indium, element M, and zinc is preferably within the above-mentioned range.

[0250] Preferably, the following metal oxide is used: the ratio of the number of indium atoms in the main component elements contained in the metal oxide relative to the total number of atoms of the metal elements is 30 atomic% or more and 100 atomic% or less, preferably 30 atomic% or more and 95 atomic% or less, more preferably 35 atomic% or more and 95 atomic% or less, more preferably 35 atomic% or more and 90 atomic% or less, more preferably 40 atomic% or more and 90 atomic% or less, more preferably 45 atomic% or more and 90 atomic% or less, more preferably 50 atomic% or more and 80 atomic% or less, more preferably 60 atomic% or more and 80 atomic% or less, more preferably 70 atomic% or more and 80 atomic% or less. For example, when In-M-Zn oxide is used as a semiconductor layer, the ratio of the number of indium atoms relative to the total number of atoms of indium, element M, and zinc is preferably within the above range.

[0251] As described above, the field-effect mobility of an OS transistor can be improved by increasing the ratio of indium atoms to the total number of atoms of the metal elements among the main constituent elements contained in the metal oxide. Using this transistor, circuits capable of high-speed operation can be fabricated. Furthermore, the circuit footprint can be reduced.

[0252] The composition of metal oxides can be analyzed using methods such as energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP-MS), or inductively coupled plasma atomic emission spectrometry (ICP-AES). Alternatively, multiple methods can be combined. Note that the actual content of elements with low concentrations can sometimes differ from the analytically obtained content due to variations in analytical precision. For example, when the content of element M is low, the analytically obtained content of element M may sometimes be lower than the actual content.

[0253] Metal oxides are preferably formed using sputtering or ALD methods. Note that when forming metal oxides using sputtering, the atomic ratio of the target material may differ from the atomic ratio of the metal oxide. In particular, the atomic ratio of zinc in the metal oxide is sometimes lower than the atomic ratio of zinc in the target material. Specifically, this zinc atomic ratio is sometimes about 40% to 90% of the zinc atomic ratio in the target material.

[0254] Furthermore, when depositing metal oxides by sputtering, the above atomic ratio is not limited to the atomic ratio of the deposited metal oxide, but can also be the atomic ratio of the sputtering target used for depositing the metal oxide.

[0255] This section explains transistor reliability. One indicator of transistor reliability is the GBT (Gate Bias Temperature) stress test, which tests the transistor under high temperature while maintaining an applied electric field at the gate. Specifically, the test under high temperature with a positive gate potential (positive bias) relative to the source and drain potentials is called the PBTS (Positive Bias Temperature Stress) test, and the test under high temperature with a negative gate potential (negative bias) is called the NBTS (Negative Bias Temperature Stress) test. Furthermore, the PBTS and NBTS tests performed under illumination are respectively called the PBTIS (Positive Bias Temperature Illumination Stress) test and the NBTIS (Negative Bias Temperature Illumination Stress) test.

[0256] In an n-channel transistor, a positive potential is applied to the gate to turn the transistor on. Therefore, the variation in the threshold voltage of the PBTS test is one of the important factors to consider as a reliability indicator of the transistor.

[0257] By using a metal oxide that does not contain gallium or has a low gallium content in the semiconductor layer, a transistor with high reliability under forward bias can be realized. In other words, a transistor with small variations in threshold voltage during PBTS testing can be achieved. Furthermore, when using a gallium-containing metal oxide, the gallium content is preferably lower than the indium content. This results in a transistor with high reliability.

[0258] One reason for the variation in threshold voltage during PBTS testing can be the presence of defect states at or near the interface between the semiconductor layer and the gate insulating layer. A higher defect state density results in more significant degradation during PBTS testing. The formation of these defect states can be suppressed by reducing the gallium content in the region of the semiconductor layer that contacts the gate insulating layer.

[0259] The reasoning behind suppressing threshold voltage variations in PBTS testing by using metal oxides containing little or no gallium in the semiconductor layer is as follows: Gallium contained in metal oxides more readily absorbs oxygen compared to other metals (e.g., indium or zinc). Therefore, it can be inferred that at the interface between the metal oxide containing more gallium and the gate insulating layer, carrier (electron) trap sites are easily created through gallium bonding with excess oxygen in the gate insulating layer. Consequently, when a positive potential is applied to the gate, carriers are trapped at the interface between the semiconductor layer and the gate insulating layer, causing a change in the threshold voltage.

[0260] More specifically, when using In-Ga-Zn oxide as the semiconductor layer, a metal oxide with an indium atomic ratio higher than that of gallium can be used. More preferably, a metal oxide with a zinc atomic ratio greater than that of gallium is used. In other words, a metal oxide with a metal element atomic ratio satisfying In>Ga and Zn>Ga is used as the semiconductor layer.

[0261] For example, the semiconductor layer of an OS transistor can use metal elements with atomic ratios of In:Ga:Zn=2:1:3, In:Ga:Zn=3:1:2, In:Ga:Zn=4:2:3, In:Ga:Zn=4:2:4.1, In:Ga:Zn=5:1:3, In:Ga:Zn=5:1:6, In:Ga:Zn=5:1:7, In:Ga:Zn=5:1:8, In: Metal oxides of Ga:Zn=6:1:6, In:Ga:Zn=10:1:3, In:Ga:Zn=10:1:6, In:Ga:Zn=10:1:7, In:Ga:Zn=10:1:8, In:Ga:Zn=5:2:5, In:Ga:Zn=10:1:10, In:Ga:Zn=20:1:10, In:Ga:Zn=40:1:10 or similar.

[0262] The semiconductor layer of the OS transistor preferably uses a metal oxide with a gallium atomic ratio relative to the number of atoms of the included metal element that is greater than 0 atomic% and less than 50 atomic%; preferably 0.1 atomic% or more and less than 40 atomic%; more preferably 0.1 atomic% or more and less than 35 atomic%; more preferably 0.1 atomic% or more and less than 30 atomic%; more preferably 0.1 atomic% or more and less than 25 atomic%; more preferably 0.1 atomic% or more and less than 20 atomic%; more preferably 0.1 atomic% or more and less than 15 atomic%; and more preferably 0.1 atomic% or more and less than 10 atomic%. By reducing the gallium content in the semiconductor layer, a transistor with high tolerance to PBTS testing can be achieved. Note that by including gallium in the metal oxide, it is less likely to generate oxygen vacancies (V0) in the metal oxide. O The effect of Oxygen Vacancy.

[0263] Gallium-free metal oxides can also be used as the semiconductor layer of an OS transistor. For example, In-Zn oxide can be used as the semiconductor layer. In this case, increasing the atomic ratio of indium to the number of atoms of the metal element in the metal oxide can improve the field-effect mobility of the transistor. On the other hand, increasing the atomic ratio of zinc to the number of atoms of the metal element in the metal oxide results in high crystallinity of the metal oxide, thus suppressing variations in the electrical characteristics of the transistor and improving reliability. Furthermore, metal oxides that do not contain gallium or zinc, such as indium oxide, can also be used as the semiconductor layer. By using gallium-free metal oxides, the variation in the threshold voltage during PBTS testing can be made extremely small.

[0264] For example, oxides containing indium and zinc can be used as semiconductor layers. In this case, metal oxides with an atomic ratio of, for example, In:Zn = 2:3, In:Zn = 4:1, or similar can be used.

[0265] Note that while gallium is used as an example, this approach can also be applied to cases where element M is used instead of gallium. It is preferable to use a metal oxide with a higher atomic ratio of indium than that of element M in the semiconductor layer. Furthermore, it is preferable to use a metal oxide with a higher atomic ratio of zinc than that of element M.

[0266] By using a metal oxide with a low content of element M as the semiconductor layer, a transistor with high reliability under forward bias can be realized. By using this transistor as a transistor requiring high reliability under forward bias, a highly reliable semiconductor device can be realized.

[0267] The semiconductor layer can also have a stacked structure comprising two or more metal oxide layers. The compositions of the two or more metal oxide layers included in the semiconductor layer can also be the same or substantially the same. By employing a stacked structure of metal oxide layers with the same composition, for example, the same sputtering target can be used for formation, thus reducing manufacturing costs.

[0268] The compositions of the two or more metal oxide layers included in the semiconductor layer can also be different. For example, a stacked structure is preferred, consisting of a first metal oxide layer having an In:M:Zn ratio of 1:3:4 or similar, and a second metal oxide layer disposed on the first metal oxide layer having an In:M:Zn ratio of 1:1:1 or similar. Furthermore, gallium or aluminum is particularly preferred as element M. For example, a stacked structure can be used consisting of any one selected from indium oxide, indium gallium oxide, and IGZO, and any one selected from IAZO, IAGZO, and ITZO (registered trademark).

[0269] For example, a stacked structure can also be used, consisting of a first metal oxide layer with an In:M:Zn ratio of 1:1:1 or similar, and a second metal oxide layer with an In:Zn ratio of 4:1 or similar disposed on the first metal oxide layer.

[0270] Crystalline metal oxide layers are preferably used as the semiconductor layer. For example, metal oxide layers with CAAC (c-axis aligned crystalline), polycrystalline, or nanocrystalline structures can be used. By using crystalline metal oxide layers as the semiconductor layer, the defect state density in the semiconductor layer can be reduced, thereby enabling highly reliable display devices. Note that a CAAC structure is a crystal structure in which multiple microcrystals (typically, multiple IGZO microcrystals) are c-axis aligned and connected on the ab plane in a manner where the multiple microcrystals are not aligned. Compared to polycrystalline structures, CAAC structures have fewer grain boundaries and grains on the ab plane, thus enabling highly reliable semiconductor devices.

[0271] The higher the crystallinity of the metal oxide layer used in semiconductor layers, the lower the defect state density in the semiconductor layer can be. On the other hand, by using metal oxide layers with low crystallinity, transistors capable of carrying large currents can be realized.

[0272] When forming metal oxide layers using sputtering, the higher the substrate temperature (stage temperature) during formation, the more crystalline the metal oxide layer can be formed. Furthermore, the higher the oxygen flow rate ratio relative to the overall deposition gas used during formation (hereinafter also referred to as the oxygen flow rate ratio), the more crystalline the metal oxide layer can be formed.

[0273] The semiconductor layer of an OS transistor can also have a stacked structure of two or more metal oxide layers with different crystallinity. For example, it can have a stacked structure of a first metal oxide layer and a second metal oxide layer disposed on the first metal oxide layer, and the second metal oxide layer can also have regions where its crystallinity is higher than that of the first metal oxide layer. Alternatively, the second metal oxide layer can also have regions where its crystallinity is lower than that of the first metal oxide layer. The compositions of the two or more metal oxide layers included in the semiconductor layer can also be the same or substantially the same. By using a stacked structure of metal oxide layers with the same composition, for example, the same sputtering target can be used to form it, thus reducing manufacturing costs. For example, by using the same sputtering target with different oxygen flow ratios, a stacked structure of two or more metal oxide layers with different crystallinity can also be formed. Note that the compositions of the two or more metal oxide layers included in the semiconductor layer can also be different from each other.

[0274] When an oxide semiconductor is used in the semiconductor layer 163 of transistors 233 to 236, insulating layers 157 and 159 are preferably made of hydrogen-containing materials. When the hydrogen-containing insulating layer contacts the oxide semiconductor, the oxide semiconductor in the region where the insulating layer contacts is n-typed, and can be used as a source region or a drain region. For example, materials containing silicon, nitrogen, and hydrogen can be used as the insulating layer. Specifically, hydrogen-containing silicon nitride, hydrogen-containing silicon oxynitride, etc., can be used.

[0275] The thicknesses of insulating layers 157 and 159 are preferably 1 nm or more and 15 nm or less, more preferably 2 nm or more and 10 nm or less, further preferably 3 nm or more and 7 nm or less, and even more preferably 3 nm or more and 5 nm or less. When an oxide semiconductor is used as the semiconductor layer 163, the regions of the semiconductor layer 163 that contact the hydrogen-containing insulating layer 157 and the regions that contact the hydrogen-containing insulating layer 159 are used as source regions or drain regions. By adjusting the thicknesses of insulating layers 157 and 159, the dimensions of the source and drain regions formed in the semiconductor layer 163 can be controlled.

[0276] The thickness of the insulating layer 158 is preferably 1 nm or more and 50 nm or less, more preferably 2 nm or more and 30 nm or less, and even more preferably 3 nm or more and 20 nm or less. By adjusting the thickness of the insulating layer 158, the size of the channel formation region of the semiconductor layer 163 can be controlled.

[0277] The thicknesses of insulating layers 157, 158 and 159 can be appropriately set according to the required characteristics of the transistor.

[0278] Furthermore, the deposition of insulating layers 157, 158, and 159 is preferably carried out continuously without exposure to the atmospheric environment. By continuously depositing insulating layers 157, 158, and 159 without exposure to the atmospheric environment, impurities or moisture can be prevented from adhering to the interface between insulating layers 157 and 158 and the interface between insulating layers 158 and 159 from the atmospheric environment.

[0279] Furthermore, when an oxide semiconductor is used for the semiconductor layer 163, the conductive layer 155 and the conductive layer 161 in contact with the semiconductor layer 163 are preferably made of conductive materials that n-type the oxide semiconductor. For example, a conductive material containing nitrogen can be used. For example, a conductive material containing titanium or tantalum and nitrogen can be used. Alternatively, other conductive materials can be disposed in a manner that overlaps with the nitrogen-containing conductive material.

[0280] On the other hand, when an oxide semiconductor is used for the semiconductor layer 163 of transistors 233 to 236, the insulating layer 158 is preferably made of a material containing oxygen and with reduced hydrogen content. For example, a material containing silicon and oxygen can be used. Specifically, silicon oxide, silicon oxynitride, etc., are used. In oxide semiconductors, hydrogen is an impurity element, so when the semiconductor layer 163 of the oxide semiconductor is in contact with the hydrogen-reducing insulating layer 158, the semiconductor layer 163 is less likely to be n-type. In addition, when the semiconductor layer 163 of the oxide semiconductor is in contact with the oxygen-containing insulating layer 158, the oxygen vacancies in the semiconductor layer 163 are reduced, the characteristics of the transistor become more stable, and the reliability is improved.

[0281] Note that in the structures of transistors 333 to 336, semiconductor layer 163 is not in contact with insulating layers 157 and 159. In the structures of transistors 333 to 336, semiconductor layer 163 is in contact with insulating layers 181a and 164. When an oxide semiconductor is used for semiconductor layer 163 of transistors 333 to 336, it is preferable that both insulating layers 181a and 164 are made of oxygen-containing materials with reduced hydrogen content.

[0282] Furthermore, when an oxide semiconductor is used as the semiconductor layer 163 of transistors 233 to 236, the insulating layer 158 preferably contains excess oxygen. In this specification, excess oxygen refers to oxygen that is removed by heating. Moreover, when a material containing excess oxygen is used in insulating layer 158, insulating layers 157 and 159 are preferably made of materials that do not readily allow oxygen to permeate. Examples of materials that do not readily allow oxygen to permeate include oxides containing one or both of aluminum and hafnium, silicon nitrides, etc. By using materials that do not readily allow oxygen to permeate in insulating layers 157 and 159, excess oxygen contained in insulating layer 158 is less likely to detach to the lower or upper layers. Therefore, sufficient oxygen can be supplied to the oxide semiconductor. For example, an insulating layer (insulating layer 158) containing silicon and oxygen can be included between two insulating layers (insulating layer 157 and insulating layer 159) containing silicon and nitrogen.

[0283] For the same reason, when an oxide semiconductor is used for the semiconductor layer 163 of transistors 333 to 336, the insulating layer 181 preferably contains excess oxygen. Additionally, the insulating layer 164 in contact with the semiconductor layer 163 also preferably contains excess oxygen.

[0284] Furthermore, by using an oxide semiconductor for the semiconductor layer 163, which serves as transistors 233 to 236, and using a hydrogen-containing material for the insulating layers 157 and 159, hydrogen is supplied to the regions of semiconductor layer 163 that contact the insulating layer 157 and the regions of semiconductor layer 163 that contact the insulating layer 159, and each region in semiconductor layer 163 is n-type. Therefore, the regions of semiconductor layer 163 that contact the conductive layer 161 and the regions of semiconductor layer 163 that contact the insulating layer 159 are used as one of the source (source region) and the drain (drain region). Additionally, the regions of semiconductor layer 163 that contact the conductive layer 155 and the regions of semiconductor layer 163 that contact the insulating layer 157 are used as the other of the source (source region) and the drain (drain region).

[0285] Figure 16A Show Figure 1B The diagram shows an enlarged cross-sectional view of transistor 233. In the above structure, in the VFET transistor 233, the length of the side of the insulating layer 158 in the opening 162a when viewed from the X or Y direction is the channel length L (channel length L1). Therefore, the channel length L of transistor 233 is determined according to the thickness t1 of the insulating layer 158.

[0286] Alternatively, insulating layers 157 and 159 can be made of materials containing no hydrogen or very little hydrogen. For example, silicon nitride or silicon oxynitride with very little hydrogen can be used. In this case, the regions where semiconductor layer 163a contacts insulating layer 157 and the regions where semiconductor layer 163a contacts insulating layer 159 are not n-type. Therefore, the region of semiconductor layer 163a that contacts conductive layer 161a is used as one of the source (source region) and drain (drain region). The region of semiconductor layer 163a that contacts conductive layer 155a is used as the other of the source (source region) and drain (drain region). Furthermore, the region of semiconductor layer 163a that contacts the side of insulating layer 158 is used as a channel formation region.

[0287] In this case, viewed from the X or Y direction, the total length of the side surfaces of the insulating layers 157, 158, and 159 in the opening 162a is the channel length L (channel length L2). Therefore, the channel length L of the transistor 233 is determined based on the total thickness t2 of the insulating layers 157, 158, and 159.

[0288] Figure 17A and Figure 17B Show Figure 16A A variation example. Alternatively, insulating layers 157 and 159 can be omitted, and only insulating layer 158 can be provided, making insulating layer 158 contact with conductive layers 155a and 161a (see [reference]). Figure 17AIn this case, when viewed from the X or Y direction, the length of the side of the insulating layer 158 in the opening 162a is the channel length L (channel length L2). Therefore, the channel length L of the transistor 233 is determined according to the thickness of the insulating layer 158. Furthermore, when using... Figure 17A In the structure shown, insulating layer 158 is sometimes referred to as insulating layer 156. Note that... Figure 17A The channel length L2 shown is Figure 16A The channel length L2 shown is synonymous with . Figure 17A The thickness t2 shown is related to Figure 16A The thickness t2 shown is synonymous.

[0289] Furthermore, when an oxide semiconductor is used as the semiconductor layer 163a, hydrogen-containing materials are used as insulating layers 157 and 159, and a material containing excess oxygen is used as the insulating layer 158, the hydrogen in insulating layers 157 and 159 bonds with the excess oxygen in insulating layer 158. Consequently, the regions of semiconductor layer 163a in contact with insulating layer 157 and insulating layer 159 are not adequately supplied with hydrogen and are therefore less likely to be n-typed. Similarly, the regions of semiconductor layer 163a in contact with insulating layer 158 are not adequately supplied with oxygen.

[0290] To solve the above problems, an insulating layer 171 that is not easily permeable to oxygen and nitrogen can be disposed between insulating layers 157 and 158, and an insulating layer 172 that is not easily permeable to oxygen and nitrogen can be disposed between insulating layers 159 and 158 (see reference). Figure 17B For example, silicon nitrides and similar materials can be used to create materials that are not easily permeable by oxygen and nitrogen. Note that when using... Figure 17B When the structure shown is used, insulating layers 157, 171, 158, 172 and 159 can be collectively referred to as insulating layer 156.

[0291] When oxygen-impermeable materials are used as insulating layers 171 and 172, the bonding of hydrogen in insulating layers 157 and 159 with excess oxygen in insulating layer 158 is blocked. Therefore, the regions of semiconductor layer 163a in contact with insulating layer 157 and with insulating layer 159 are supplied with sufficient hydrogen. Similarly, the regions of semiconductor layer 163a in contact with insulating layer 158 are supplied with sufficient oxygen.

[0292] In this case, when viewed from the X or Y direction, the total length of the side surfaces of insulating layers 171, 158, and 172 in opening 162a is the channel length L3. Therefore, the channel length L of transistor 233 is determined based on the total thickness t3 of insulating layers 171, 158, and 172.

[0293] The channel length L of transistor 233 is determined by the thickness of the insulating layer disposed between conductive layer 161a and conductive layer 155a. Therefore, transistors with short channel lengths L can be manufactured with high precision. Furthermore, characteristic inhomogeneities between multiple transistors can be reduced. Thus, the semiconductor device including transistor 233 operates stably, improving reliability. Additionally, as characteristic inhomogeneities are reduced, the circuit design freedom of the semiconductor device increases, and the operating voltage can be lowered. Therefore, the power consumption of the semiconductor device can be reduced.

[0294] Note that in this embodiment, a structure is shown comprising three insulating layers (insulating layer 157, insulating layer 158, insulating layer 159) or five insulating layers (insulating layer 157, insulating layer 158, insulating layer 159, insulating layer 171, insulating layer 172) between conductive layer 155a and conductive layer 161a. However, the number of insulating layers between conductive layer 155a and conductive layer 161a is not limited to this. The insulating layers between conductive layer 155a and conductive layer 161a may also be one, two, four, or six or more.

[0295] Furthermore, to improve the coverage of the semiconductor layer 163a, insulating layer 164, and conductive layer 165a formed in the opening 162a, the cone angle θ of the side surface of the opening 162a, i.e., the cone angle θ of the side surface of each of the insulating layers 157, 158, and 159, is set to 45 degrees or more and 90 degrees or less, preferably 50 degrees or more and 75 degrees or less. Note that the cone angle θ of the side surface of a layer (insulating layer, conductive layer, or semiconductor layer) refers to the angle between the bottom surface and the side surface of that layer (refer to...). Figure 16A ).

[0296] In addition, such as Figure 18 As shown, if there are no issues with the coverage of the semiconductor layer 163a, insulating layer 164, and conductive layer 165a, the side surface of the opening 162a can be made perpendicular to or substantially perpendicular to the surface on which the opening 162a is formed (e.g., the top surface of the conductive layer 155a). By making the side surface of the opening 162a perpendicular or substantially perpendicular, the occupied area of ​​the transistor 233 can be reduced. Therefore, the occupied area of ​​the memory element including the transistor 233 can be reduced.

[0297] Since the semiconductor layer 163a is disposed in the opening 162a, the perimeter of the opening 162a when viewed from the Z direction is equal to the channel width W of the transistor 233 (refer to...). Figure 16B As the perimeter, for example, the perimeter of the location at half the thickness t1 or half the thickness t2 of the insulating layer 158 can be determined. Note that, as needed, the perimeter of any location of the opening 162a can also be set as the channel width W. For example, the perimeter of the lowermost part of the opening 162a can be set as the channel width W, or the perimeter of the uppermost part of the opening 162a can be set as the channel width W.

[0298] Furthermore, in one embodiment of the storage device of the present invention, the channel length L is preferably at least less than the channel width W. In one embodiment of the present invention, the channel length L is preferably 0.1 times or more and 0.99 times or less, and more preferably 0.5 times or more and 0.8 times or less, of the channel width W.

[0299] In addition, Figure 16B In the diagram, the outline (planar shape) of the opening 162a as viewed from the Z direction is shown as a circle, but it is not limited to this. For example, the outline of the opening 162a as viewed from the Z direction can also be elliptical (see reference). Figure 16C ) or rectangle (refer to) Figure 16D ).Notice, Figure 16D A rectangle with curved corners is shown. Furthermore, for example, the outline of the opening 162a when viewed from the Z direction can also be a shape including one or both of a straight portion and a curved portion (see [reference]). Figure 16E ).

[0300] Furthermore, the opening 162a is preferably small. For example, the maximum width of the opening 162a when viewed from the Z direction is preferably 60 nm or less, more preferably 50 nm or less, further preferably 40 nm or less, and especially preferably 30 nm or less. The maximum width of the opening 162a when viewed from the Z direction may also be 20 nm or less. In addition, the minimum width of the opening 162a when viewed from the Z direction is preferably 1 nm or more, more preferably 5 nm or more. To form the aforementioned small opening 162a, photolithography using short-wavelength light such as EUV light or an electron beam is preferred.

[0301] Furthermore, transistors 234 to 236 have the same structure as transistor 233. To avoid repetition, the description of transistors 234 to 236 is omitted.

[0302] Figure 19A Show Figure 11B The diagram shows an enlarged cross-section of transistor 333. Transistor 333 is also a variation of transistor 233. In transistor 333 of the VFET, the length of the side of the conductive layer 175a in the opening 162a when viewed from the X or Y direction is called the channel length L (channel length L4). Therefore, the channel length L of transistor 333 is determined according to the thickness t4 of the conductive layer 175a. When viewed from the X or Y direction, the region where the semiconductor layer 163a overlaps with the conductive layer 175a is used as the channel formation region.

[0303] In addition, transistor 333 has a structure in which an electric field formed around the channel by the conductive layer 175a used as the gate electrode forms a region, so the structure can be described as a GAA (Gate All Around) structure.

[0304] Figure 19B Show Figure 19A A variation is shown. Transistor 333 may also include a conductive layer 165 on the insulating layer 164 in the region overlapping with opening 162a when viewed from the Z direction. Figure 19B In the structure shown, both conductive layer 165 and conductive layer 175 can be used as gate electrodes. Figure 19B In the structure shown, sometimes one of the conductive layers 165 and 175 is referred to as the "gate electrode" and the other as the "back gate electrode". Additionally, sometimes one of the conductive layers 165 and 175 is referred to as the "first gate electrode" and the other as the "second gate electrode". For example, sometimes the conductive layer 165 is referred to as the "gate electrode" and the conductive layer 175 as the "back gate electrode".

[0305] The gate electrode is configured such that a channel forming region is formed between the gate electrode and the back gate electrode, sandwiching a semiconductor layer. Both the gate electrode and the back gate electrode are formed using conductive layers. When the gate electrode is used to control the on and off states of the transistor, the potential of the back gate electrode can be the same as the gate electrode, or it can be GND or any other potential. Furthermore, the threshold voltage of the transistor can be changed by independently changing the potential of the back gate electrode without being linked to the gate electrode. In addition, since the gate electrode and the back gate electrode are formed using conductive materials, they have the function of preventing electric fields generated outside the transistor from affecting the semiconductor layer forming the channel (especially the function of shielding against electric fields such as static electricity). By providing a back gate electrode in addition to the gate electrode, characteristic inhomogeneities between transistors can be reduced.

[0306] exist Figure 19B In the structure shown, when the conductive layer 165 is used as the gate electrode, the distance from the top surface of the conductive layer 155a to the top surface of the conductive layer 161a when viewed from the X or Y direction is the channel length L (channel length L5). At this time, when viewed from the X or Y direction, the total length of each side surface of the opening 162a of the insulating layer 157, conductive layer 175a, insulating layer 159, and conductive layer 161a is the channel length L5. Therefore, the channel forming region of the transistor 333 includes the region along the side surface of the insulating layer 157, the region along the side surface of the conductive layer 175a, the region along the side surface of the insulating layer 159, and the region along the side surface of the conductive layer 161a. The thickness t5 is determined by the sum of the thicknesses of the insulating layer 157, conductive layer 175a, insulating layer 159, and conductive layer 161a. Figure 19B The channel length L of the transistor 333 shown.

[0307] Furthermore, transistors 334 to 336 have the same structure as transistor 333. To avoid repetition, the description of transistors 334 to 336 is omitted.

[0308] The structure shown in this embodiment can be implemented by appropriately combining it with the structures shown in other embodiments.

[0309] (Implementation Method 2)

[0310] In this embodiment, a storage cell array 200 including a storage element 100 according to one aspect of the present invention and a storage device 300 including the storage cell array 200 are described.

[0311] <Storage device 300>

[0312] Figure 20A This is a block diagram illustrating a structural example of a storage device 300 including a storage element 100 according to one aspect of the present invention. Figure 20A The storage device 300 shown includes a storage cell array 200 and a drive circuit 21.

[0313] The storage cell array 200 includes multiple storage elements 100 configured in a matrix shape with m rows and n columns (m and n are integers greater than or equal to 1). By configuring the multiple storage elements 100 in a matrix shape, a storage device with a large storage capacity can be realized.

[0314] exist Figure 20A In this diagram, the storage element 100 in the first row and first column is denoted as storage element 100[1, 1], the storage element 100 in the m-th row and n-th column is denoted as storage element 100[m, n], the storage element 100 in the m-th row and first column is denoted as storage element 100[m, 1], the storage element 100 in the first row and n-th column is denoted as storage element 100[1, n], the storage element 100 in the m-th row and n-th column is denoted as storage element 100[m, n], and the storage element 100 in the i-th row and j-th column is denoted as storage element 100[i, j]. Note that i represents an integer greater than 1 and less than m in any row, and j represents an integer greater than 1 and less than n in any column.

[0315] Furthermore, rows and columns extend in directions orthogonal to each other. In this embodiment, the X direction (the direction along the X-axis) is referred to as a "row" and the Y direction (the direction along the Y-axis) is referred to as a "column," but it is also possible to refer to the X direction as a "column" and the Y direction as a "row."

[0316] The drive circuit 21 includes a PSW 22 (power switch), a PSW 23, and peripheral circuit 31. The peripheral circuit 31 includes peripheral circuit 41, a control circuit 32, and a voltage generation circuit 33.

[0317] In the storage device 300, the aforementioned circuits, signals, and voltages can be appropriately selected or omitted as needed. Alternatively, other circuits or signals can be added. Signals BW, CE, GW, CLK, WAKE, ADDR, WDA, PON1, and PON2 are signals input from the outside, while signal RDA is a signal output to the outside. Signal CLK is the clock signal.

[0318] In addition, signals BW, CE, and GW are control signals. Signal CE is the chip enable signal, signal GW is the global write enable signal, and signal BW is the byte write enable signal. Signal ADDR is the address signal. Signal WDA is for writing data, and signal RDA is for reading data. Signals PON1 and PON2 are power gating control signals. Furthermore, signals PON1 and PON2 can also be generated in control circuit 32.

[0319] The control circuit 32 is a logic circuit that controls the overall operation of the storage device 300. For example, the control circuit performs logical operations on signals CE, GW, and BW to determine the operating mode of the storage device 300 (e.g., write operation, read operation). Alternatively, the control circuit 32 generates control signals for the peripheral circuit 41 to execute the aforementioned operating mode.

[0320] The voltage generation circuit 33 has the function of generating voltage. The signal WAKE has the function of controlling the input signal CLK to the voltage generation circuit 33. For example, when the signal WAKE supplies the potential H, the signal CLK is input to the voltage generation circuit 33, and the voltage generation circuit 33 generates voltage.

[0321] The peripheral circuit 41 is used to write and read data from the storage element 100. The peripheral circuit 41 includes a row decoder 42, a column decoder 44, a row driver 43, a column driver 45, an input circuit 47, and an output circuit 48.

[0322] Row decoder 42 and column decoder 44 are used to decode the signal ADDR. Row decoder 42 is a circuit used to specify the row to be accessed, and column decoder 44 is a circuit used to specify the column to be accessed. Row driver 43 is used to select the wiring specified by row decoder 42. Column driver 45 has the following functions: writing data to storage element 100; reading data from storage element 100; and holding the read data.

[0323] Input circuit 47 has the function of holding signal WDA. The data held in input circuit 47 is output to column driver 45. The output data of input circuit 47 is the data (Din) written to storage element 100. The data (Dout) read from storage element 100 by column driver 45 is output to output circuit 48. Output circuit 48 has the function of holding Dout. In addition, output circuit 48 has the function of outputting Dout to the outside of storage device 300. The data output from output circuit 48 is signal RDA.

[0324] PSW22 controls the supply of VDD to the peripheral circuit 31. PSW23 controls the supply of VHM to the row driver 43. Here, the high power supply potential of the storage device 300 is VDD, and the low power supply potential is GND (ground potential). Furthermore, VHM is a high power supply potential used to make the word line a potential H, which is higher than VDD. Signal PON1 controls the on / off state of PSW22, and signal PON2 controls the on / off state of PSW23. Figure 20A In the peripheral circuit 31, the number of power domains supplied with VDD is 1, but it can also be multiple. In this case, a power switch can be set for each power domain.

[0325] Furthermore, the memory cell array 200 and the drive circuit 21 can also overlap. By arranging the memory cell array 200 and the drive circuit 21 in an overlapping manner, the area occupied by the storage device 300 can be reduced. For example, as Figure 20B As shown, the storage device 300 employs a stacked structure of layer 10 and layer 20, with a driving circuit 21 formed in layer 10 and a storage cell array 200 formed in layer 20.

[0326] For example, a silicon substrate can be used as layer 10, and the driving circuit 21 can be formed on this silicon substrate. By using a silicon substrate as layer 10, a transistor (Si transistor) containing silicon in the channel formation region can be used as the transistor constituting the driving circuit 21. Alternatively, by using a single-crystal silicon substrate as layer 10, a single-crystal Si transistor containing a single-crystal semiconductor in the channel formation region and operating at high speed can be used as the transistor constituting the driving circuit 21.

[0327] Furthermore, SOI substrates can also be used as layer 10, for example. SOI substrates can be formed using: SIMOX (Separation by Implanted Oxygen) substrates, which are formed by heating a mirror-polished sheet at high temperature after implanting oxygen ions to create an oxide layer at a certain depth from the surface, thus eliminating defects generated in the surface layer; and SOI substrates formed using methods such as smart lift-off or ELTRAN (Epitaxial Layer Transfer), which utilize the micro-voids formed by implanting hydrogen ions to grow the semiconductor substrate through heat treatment. Si transistors fabricated using SOI substrates exhibit reduced parasitic capacitance, enabling high-speed operation.

[0328] The OS transistor constituting the memory element 100 according to one embodiment of the present invention is a thin-film transistor, so it can be easily stacked with layer 10 as layer 20. Furthermore, as described above, the OS transistor operates stably at high temperatures with minimal characteristic variation. Therefore, even when a memory cell array 200 including OS transistors is stacked on top of a drive circuit 21 including Si transistors, it is less susceptible to the heat generated by the drive circuit 21, thereby achieving high reliability.

[0329] In addition, such as Figure 20C As shown, a layer 20 including a memory cell array 200 can also be repeatedly overlapped on a layer 10 including a driving circuit 21. Figure 20C An example is shown where layer 20 is stacked on layer 10 with k layers (k being an integer greater than 2). In addition, layer 20, which is the first layer on layer 10, is referred to as layer 20[1], and layer 20, which is the kth layer, is referred to as layer 20[k].

[0330] By overlapping the layer 10 including the driving circuit 21 and the layer 20 including the memory cell array 200, the signal transmission distance between the driving circuit 21 and the memory cell array 200 can be shortened. Therefore, the parasitic resistance and capacitance between the driving circuit 21 and the memory array 200 are reduced, resulting in reduced power consumption and signal delay. Furthermore, the storage device 300 can be miniaturized. Additionally, the storage capacity per unit area can be increased.

[0331] Figure 21 A more specific example of the stacked structure of the storage device 300 is shown. Figure 21 In the middle, the storage element 100 included in layer 20 is shown Figure 1A and Figure 1B The structure is shown. To avoid repetition, the description of storage element 100 is omitted here.

[0332] In addition, Figure 21In the diagram, transistor 800 is shown as a transistor included in the driving circuit 21. Transistor 800 is disposed on substrate 371 and includes: a conductive layer 376 serving as a gate; an insulating layer 375 serving as a gate insulating layer; a semiconductor region 373 formed by a portion of substrate 371; and low-resistance regions 374a and 374b serving as source or drain regions. Transistor 800 can be a p-channel transistor or an n-channel transistor. Substrate 371 can be, for example, a single-crystal silicon substrate.

[0333] exist Figure 21 In the transistor 800 shown, the semiconductor region 373 (a portion of the substrate 371) forming the channel has a convex shape. Furthermore, a conductive layer 376 covers the sides and top surface of the semiconductor region 373 across an insulating layer 375. The conductive layer 376 can also be made of a material with adjustable work function. Because of the convex portion of the semiconductor substrate, this transistor 800 is also called a FIN-type transistor. Additionally, an insulating layer for forming the convex portion can be provided in contact with the upper surface of the convex portion. Furthermore, although the case where the convex portion is formed by processing a portion of the semiconductor substrate is shown here, a semiconductor film with a convex shape can also be formed by processing an SOI substrate.

[0334] Notice, Figure 21 The structure of transistor 800 shown is just an example and is not limited to the above structure. Appropriate transistors can be used depending on the circuit structure or driving method.

[0335] Layers 10 and 20 may also include wiring layers, including conductive layers such as contact plugs, and interlayer insulating layers. Furthermore, multiple wiring layers may be provided depending on the design. Additionally, in this specification, wiring and contact plugs electrically connected to the wiring may also be components. That is, a portion of the conductive layer is sometimes used as wiring, and another portion of the conductive layer is sometimes used as a contact plug.

[0336] For example, on transistor 800, insulating layers 390, 391, 393, and 394 are sequentially stacked as interlayer insulating layers. A conductive layer 392 is provided through insulating layers 390 and 391. A conductive layer 395 is provided through insulating layers 393 and 394.

[0337] Furthermore, the insulating layer used as an interlayer insulating layer can also be used as a planarization film covering the uneven shape underneath. For example, to improve flatness, the top surface of the insulating layer 391 can be subjected to CMP treatment, etc.

[0338] Interlayer insulation layers and wiring layers can also be disposed on insulating layer 394 and conductive layer 395. For example, in Figure 21In this structure, insulating layers 396, 381, 382, ​​383, 384, 385, 386, and 387 are sequentially stacked on insulating layer 394 and conductive layer 395. Furthermore, conductive layers 361, 362, 363, 364, 365, 366, and 367 are included, passing through insulating layers 396 and 381, respectively.

[0339] exist Figure 21 In this configuration, the low-resistance region 374b of transistor 800 and the conductive layer 155b of transistor 234 are electrically connected via conductive layers 392, 395, 361, 362, 363, 364, 365, 366, and 367. Conductive layers 392, 395, 361, 362, 363, 364, 365, 366, and 367 are used as contact plugs or wiring.

[0340] The structure shown in this embodiment can be implemented by appropriately combining it with the structures shown in other embodiments.

[0341] (Implementation Method 3)

[0342] This embodiment describes an example of an arithmetic processing apparatus that includes a storage element 100 according to one aspect of the present invention.

[0343] In the layer 10 shown in the above embodiment, various functional circuits may be provided in addition to the driving circuit 21. Figure 22 A perspective view of an arithmetic processing device 1100, one of the semiconductor devices, is shown. The arithmetic processing device 1100 includes a layer 20, which overlaps with layer 10 and comprises a memory cell array 200 including memory elements 100. To facilitate understanding of the structure of the arithmetic processing device 1100, [further details are provided]. Figure 22 Layer 10 and layer 20 are shown separately in the image.

[0344] Figure 22The arithmetic processing unit 1100 shown includes, on layer 10: a driver circuit 21, an ALU 1191 (ALU: Arithmetic Logic Unit), an ALU controller 1192, an instruction decoder 1193, an interrupt controller 1194, a timing controller 1195, a register 1196, a register controller 1197, a bus interface 1198, a cache 1199, and a cache interface 1189. Additionally, it may include a rewritable ROM and a ROM interface. The cache 1199 and the cache interface 1189 may also be located on different chips. Figure 22 The arithmetic processing unit 1100 shown is used, for example, as a central processing unit (CPU).

[0345] The cache 1199 is connected to the main memory located on a different chip via the cache interface 1189. The cache interface 1189 has the function of supplying a portion of the data stored in the main memory to the cache 1199. The cache 1199 has the function of storing this data.

[0346] Figure 22 The arithmetic processing unit 1100 shown is merely an example with a simplified structure; therefore, the actual arithmetic processing unit 1100 may have various structures depending on its application. For example, it may also include... Figure 22 The illustrated computing processing device 1100 has a core structure, with multiple such cores configured to operate simultaneously, similar to a GPU (Graphics Processing Unit). Furthermore, the number of bits that can be processed in the internal computing circuitry and data bus of the computing processing device 1100 can be, for example, 8 bits, 16 bits, 32 bits, or 64 bits.

[0347] Instructions input to the arithmetic processing unit 1100 via the bus interface 1198 are input to the instruction decoder 1193 and, after being decoded, are input to the ALU controller 1192, interrupt controller 1194, register controller 1197, and timing controller 1195.

[0348] The ALU controller 1192, interrupt controller 1194, register controller 1197, and timing controller 1195 perform various controls based on the decoded instructions. Specifically, the ALU controller 1192 generates signals to control the operation of the ALU 1191. Furthermore, the interrupt controller 1194, when the arithmetic processing unit 1100 executes a program, determines and processes interrupt requests from external input / output devices and peripheral circuits based on their priority and mask state. The register controller 1197 generates the address of register 1196 and reads or writes register 1196 according to the state of the arithmetic processing unit 1100.

[0349] Furthermore, the timing controller 1195 generates signals to control the operating timing of the ALU 1191, ALU controller 1192, instruction decoder 1193, interrupt controller 1194, and register controller 1197. For example, the timing controller 1195 has an internal clock generator that generates an internal clock signal based on a reference clock signal and supplies the internal clock signal to the aforementioned circuits.

[0350] exist Figure 22 In the arithmetic processing unit 1100 shown, the register controller 1197 selects the holding operation of register 1196 according to instructions from ALU 1191. In other words, it selects whether data is held in the memory cells of register 1196 by flip-flops or by capacitors. When data is held by flip-flops, a power supply potential is supplied to the memory cells in register 1196. When data is held by capacitors, the data is overwritten on the capacitors, and the power supply potential to the memory cells in register 1196 can be stopped.

[0351] Figure 22 The arithmetic processing device 1100 shown includes a storage device serving as a register 1196 and a cache 1199. Alternatively, a storage cell array 200 including a storage element 100 according to one aspect of the invention may be used for this storage device.

[0352] By overlapping the functional circuitry of layer 10 with the memory cell array 200 containing memory elements 100 on layer 20, the connection distance between them can be shortened. This shortened connection distance reduces parasitic resistance and capacitance, thereby improving communication speed. Furthermore, power consumption can be reduced.

[0353] Furthermore, storage element 100 is a non-volatile storage element. Therefore, a portion or all of the storage cell array 200 can be used for storage. Additionally, a portion or all of the storage cell array 200 can be used as main memory. Furthermore, a portion or all of the storage cell array 200 can be used as cache memory.

[0354] Furthermore, a portion of the storage cell array 200 can be used as main memory and another portion as storage. The storage cell array 200, including the storage element 100 according to one aspect of the invention, can function as a cache, as main memory, and as storage. The storage cell array 200, including the storage element 100 according to one aspect of the invention, can, for example, be used as a general-purpose memory.

[0355] Furthermore, when the storage capacity of the cache 1199 is insufficient, a portion or all of the storage cell array 200, including the storage element 100 according to one aspect of the present invention, can be used to supplement the storage capacity of the cache 1199. Additionally, when data is transmitted and received between the cache 1199 and the main memory, if one of the cache 1199 and the main memory is performing other processing, the other's work may stop until that processing is completed, resulting in standby time. By temporarily storing the received data in the storage cell array 200, including the storage element 100 according to one aspect of the present invention, the aforementioned standby time can be eliminated. This improves the operating efficiency of the computing device.

[0356] Furthermore, the storage element 100 according to one aspect of the present invention is suitable for power gating to reduce power consumption by temporarily stopping the power supply to inactive arithmetic circuits. Additionally, arithmetic processing devices utilizing power gating are sometimes referred to as "normally off processors" or "Noff processors." In normally off processors, the data required for recovery needs to be backed up in non-volatile memory before power supply is stopped and read out during recovery. The storage element 100 according to one aspect of the present invention is a non-volatile storage element and can be arranged overlapping with the arithmetic processing device, thus enabling normally off processors with fast backup and recovery speeds without increasing the footprint of the arithmetic processing device.

[0357] The structure shown in this embodiment can be implemented by appropriately combining it with the structures shown in other embodiments.

[0358] (Implementation Method 4)

[0359] In this embodiment, an application example of a storage device including a storage element (hereinafter also referred to as "a storage device according to an embodiment of the present invention") is described.

[0360] Generally speaking, various storage devices can be used in semiconductor devices such as computers, depending on their application. Figure 23AThe various memory devices used in semiconductor devices are shown in a hierarchical manner. Higher-level memory devices are required to operate at faster speeds, while lower-level memory devices are required to have larger storage capacities and higher storage densities. Figure 23A In the middle, from the top layer, are the memory installed as registers in the CPU and other computing devices, SRAM (Static Random Access Memory), DRAM (Dynamic Random Access Memory), and 3D NAND memory.

[0361] Because memory installed along with registers in arithmetic processing devices such as CPUs is used for temporary storage of calculation results, it is accessed frequently by the processing device. Therefore, faster operating speed is required compared to storage capacity. Furthermore, registers also have the function of holding settings information of the processing device.

[0362] SRAM is used, for example, in caches. A cache has the function of copying and maintaining a portion of the information held in main memory. By copying frequently used data into the cache, the speed of data access can be improved. A cache requires less storage capacity than main memory, but requires a higher operating speed. Furthermore, data that is overwritten in the cache is copied and provisioned to main memory.

[0363] DRAM is used, for example, in main memory. Main memory has the function of storing programs and data read from storage. The storage density of DRAM is approximately 0.1 to 0.3 Gbit / mm². 2 .

[0364] 3D NAND flash memory is used for storage, for example. Storage functions to hold data that needs to be preserved long-term, as well as various programs used by computing devices. Therefore, compared to faster operating speeds, storage requires larger storage capacities and higher storage densities. The storage density of storage devices used for storage is approximately 0.6 to 6.0 Gbit / mm². 2 .

[0365] One aspect of the present invention provides a storage device with high operating speed and the ability to retain data for extended periods. This storage device is suitable for use as a storage device located in a boundary region 901 having a hierarchy including a cache and a hierarchy including main memory. Furthermore, this storage device is suitable for use as a storage device located in a boundary region 902 having a hierarchy including main memory and a hierarchy including storage.

[0366] Furthermore, a storage device according to one aspect of the present invention is suitable for use in both a hierarchy including main memory and a storage hierarchy. Furthermore, a storage device according to one aspect of the present invention is suitable for use in a hierarchy including a cache. Figure 23B Showing with Figure 23A Different hierarchical levels for various storage devices.

[0367] exist Figure 23B In the diagram, from top to bottom, are shown a memory installed as registers in an arithmetic processing device such as a CPU, an SRAM used as a cache, and a storage device 300 according to one embodiment of the present invention. The storage device 300 according to one embodiment of the present invention can be used as a cache, main memory, and storage. In cases where a high-speed memory of 1 GHz or higher is required as a cache, this cache is installed in an arithmetic processing device such as a CPU.

[0368] Storage device 300, including a storage element according to one aspect of the present invention, can be applied, for example, to storage devices in various electronic devices (e.g., information terminals, computers, smartphones, e-book readers, digital cameras, video cameras, video recording devices, navigation systems, game consoles, etc.). Furthermore, it can be used in image sensors, IoT (Internet of Things), and medical devices, etc. Here, computers include tablet computers, laptop computers, desktop computers, and mainframe computers such as server systems.

[0369] An example of an electronic device including a storage device according to one aspect of the present invention will be described. Figures 24A to 24J This illustrates an example of an electronic component 4700 having a storage device according to one aspect of the invention being included in various electronic devices.

[0370] [Mobile phone]

[0371] Figure 24A The information terminal 5500 shown is a mobile phone (smartphone), one type of information terminal. The information terminal 5500 includes a housing 5510, a display unit 5511, and electronic components 4700. The display unit 5511 has a touch panel as an input interface, and buttons are provided on the housing 5510.

[0372] The information terminal 5500 can store documents temporarily generated during program execution (e.g., caches when using a web browser, etc.) in an electronic component 4700 that includes a storage device according to one aspect of the invention.

[0373] Wearable devices

[0374] also, Figure 24BAn example of a wearable terminal, information terminal 5900, is shown. Information terminal 5900 includes a housing 5901, a display unit 5902, an operation switch 5903, an operation switch 5904, a watch strap 5905, electronic components 4700, etc.

[0375] Similar to the aforementioned information terminal 5500, the wearable terminal can store documents temporarily generated during program execution in an electronic component 4700 that includes a storage device according to one aspect of the invention.

[0376] [Information Terminal]

[0377] Figure 24C A desktop information terminal 5300 is shown. The desktop information terminal 5300 includes an information terminal body 5301, a display unit 5302, a keyboard 5303, and electronic components 4700.

[0378] Similar to the aforementioned information terminal 5500, the desktop information terminal 5300 can store documents temporarily generated during program execution in an electronic component 4700 that includes a storage device according to one aspect of the invention.

[0379] Note that in the example above, Figures 24A to 24C Examples of smartphones, wearable devices, and desktop information terminals are shown, but information terminals other than smartphones, wearable devices, and desktop information terminals can also be applied. Examples of information terminals other than smartphones, wearable devices, and desktop information terminals include PDAs (Personal Digital Assistants), laptop information terminals, and workstations.

[0380] [Electrical Products]

[0381] also, Figure 24D An example of an electrical appliance is shown: an electric refrigerator / freezer 5800. The electric refrigerator / freezer 5800 includes a housing 5801, a refrigerator door 5802, a freezer door 5803, and electronic components 4700, etc. For example, the electric refrigerator / freezer 5800 is an electric refrigerator / freezer corresponding to the Internet of Things (IoT).

[0382] The storage device according to one aspect of the present invention can be applied to an electric refrigerator / freezer 5800. By utilizing the Internet or the like, the electric refrigerator / freezer 5800 can send and receive information such as the food stored in the electric refrigerator / freezer 5800 or the expiration date of the food to an information terminal or the like. The electric refrigerator / freezer 5800 can store documents temporarily generated during the transmission of this information in an electronic component 4700 including a storage device according to one aspect of the present invention.

[0383] In this embodiment, an electric refrigerator / freezer is described as an electrical appliance. However, other electrical appliances could include, for example, a vacuum cleaner, microwave oven, electric oven, rice cooker, water heater, IH cooker, water dispenser, air conditioner (including air conditioner), washing machine, dryer, and audio-visual equipment.

[0384] [Game console]

[0385] also, Figure 24E A portable game console 5200 is shown as an example of a game console. The portable game console 5200 includes a casing 5201, a display unit 5202, buttons 5203, electronic components 4700, etc.

[0386] also, Figure 24F A fixed game console 7500 is shown as an example of a game console. The fixed game console 7500 includes a main body 7520, electronic components 4700, and a controller 7522. The main body 7520 can be connected to the controller 7522 wirelessly or via a wired connection. Furthermore, although in Figure 24F Although not shown in the figure, the controller 7522 may include a display unit for displaying game images, a touch panel and joystick as input interfaces other than buttons, a rotating gripper, a sliding gripper, etc. Furthermore, the controller 7522 is not limited to... Figure 24F The shape shown can also be changed depending on the type of game. For example, in shooting games such as FPS (First Person Shooter), a controller shaped like a gun can be used as the trigger button. Furthermore, in games such as music games, a controller shaped like a musical instrument or other musical device can be used. Moreover, stationary game consoles can also be equipped with cameras, depth sensors, microphones, etc., allowing players to operate the game using gestures, voice, etc., instead of the controller.

[0387] Furthermore, the images from the aforementioned game consoles can be output from display devices such as television sets, personal computer monitors, game displays, and head-mounted displays.

[0388] By using the storage device according to one aspect of the present invention in a portable game console 5200 or a stationary game console 7500, a low-power portable game console 5200 or a stationary game console 7500 can be realized. Furthermore, with the reduction in power consumption, heat generation from the circuitry is also reduced, thereby mitigating the impact of heat generation on the circuitry itself, peripheral circuitry, and modules.

[0389] Furthermore, the documents and other data temporarily generated during game execution can be stored in the electronic component 4700 of the portable game console 5200 or the stationary game console 7500.

[0390] As an example of a game console, Figure 24E A portable game console is shown. Figure 24F A home-based stationary game console is shown. However, the electronic device of this invention is not limited to this. Examples of electronic devices that can be categorized as embodiments of this invention include arcade game consoles installed in entertainment facilities (game centers, amusement parks, etc.) and ball-throwing machines installed in sports facilities.

[0391] [Moving Object]

[0392] The storage device described in the above embodiments can be applied to a car as a mobile body and to the vicinity of the driver's seat of the car.

[0393] Figure 24G An example of a moving vehicle, a car 5700, is shown. The car 5700 includes electronic components 4700. Near the driver's seat of the car 5700, there is an instrument panel that provides various information such as vehicle speed, engine speed, driving distance, remaining fuel, gear position, and air conditioning settings. Additionally, a display device showing the aforementioned information may also be provided near the driver's seat.

[0394] By displaying the exterior images captured by a camera device (not shown) installed on the vehicle 5700 on this display device, obstructions such as pillars and blind spots around the driver's seat can be filled, thereby improving safety. In other words, by displaying the exterior images captured by this camera device on this display device, blind spots can be filled, thus improving safety.

[0395] The electronic component 4700, which includes a storage device according to one aspect of the present invention, can hold information required for systems such as autonomous driving, navigation, and hazard prediction in the vehicle 5700. Furthermore, navigation, hazard prediction, and other information can be displayed on the display device of the vehicle 5700. Additionally, information captured by a dashcam installed in the vehicle 5700 can also be stored in the electronic component 4700, which includes a storage device according to one aspect of the present invention.

[0396] While the above example illustrates a moving object like a car, moving objects are not limited to cars. Examples of moving objects include trams, monorails, ships, and flying objects (helicopters, unmanned aerial vehicles, airplanes, rockets), etc.

[0397] [camera]

[0398] The storage device according to one aspect of the present invention can be applied to a camera. Figure 24HA digital camera 6240 is shown as an example of an imaging device. The digital camera 6240 includes a housing 6241, a display unit 6242, an operation switch 6243, a shutter button 6244, electronic components 4700, etc., and is equipped with a detachable lens 6246. Here, the digital camera 6240 employs a structure in which the lens 6246 can be detached from the housing 6241; however, the lens 6246 and the housing 6241 can also be formed as a single unit. Furthermore, the digital camera 6240 may also include separately mounted flash units and viewfinders, etc.

[0399] By incorporating the electronic component 4700, which includes a storage device according to one aspect of the invention, into the digital camera 6240, a low-power digital camera 6240 can be realized. Furthermore, with the reduction in power consumption, heat generation from the circuitry is also reduced, thereby mitigating the impact of heat generation on the circuitry itself, peripheral circuitry, and modules.

[0400] [Video Camera]

[0401] The storage device according to one aspect of the present invention can be applied to a video camera. Figure 24I A video camera 6300 is shown as an example of a camera device. The video camera 6300 includes a first housing 6301, a second housing 6302, a display unit 6303, an operation switch 6304, a lens 6305, a connecting part 6306, electronic components 4700, etc. The operation switch 6304 and the lens 6305 are disposed on the first housing 6301, and the display unit 6303 is disposed on the second housing 6302. The first housing 6301 and the second housing 6302 are connected by the connecting part 6306, and the angle between the first housing 6301 and the second housing 6302 can be changed by the connecting part 6306. The image on the display unit 6303 can also be switched according to the angle between the first housing 6301 and the second housing 6302 in the connecting part 6306.

[0402] When recording images captured by the video camera 6300, encoding is required according to the data recording method. By using a storage device according to one aspect of the present invention, the video camera 6300 can retain a document temporarily generated during encoding.

[0403] [ICD]

[0404] The storage device according to one aspect of the present invention can be applied to an implantable cardioverter defibrillator (ICD). Figure 24J This is a cross-sectional schematic diagram showing an example of an ICD. The ICD body 5400 includes at least a battery 5401, electronic components 4700, a regulator, a control circuit, an antenna 5404, a metal wire 5402 extending to the right atrium, a metal wire 5403 extending to the right ventricle, and electronic components 4700.

[0405] The ICD body 5400 is surgically implanted in the body. Two metal wires pass through the subclavian vein 5405 and the superior vena cava 5406, with the tip of one metal wire placed in the right ventricle and the tip of the other metal wire placed in the right atrium.

[0406] The ICD main unit 5400 has the function of a cardiac pacemaker, pacing the heart when the heart rhythm is outside the prescribed range. In addition, it can be used for defibrillation treatment when the heart rhythm does not improve even when pacing is performed (such as rapid ventricular pulse or ventricular fibrillation).

[0407] In order to perform pacing and defibrillation appropriately, the ICD body 5400 needs to monitor the heart rhythm frequently. Therefore, the ICD body 5400 includes a sensor for detecting the heart rhythm. In addition, the ICD body 5400 can store data on the heart rhythm measured by the sensor, the number of treatments performed using pacing, the duration, etc., in an electronic component 4700 including a storage device according to one aspect of the invention.

[0408] Furthermore, power is received by antenna 5404 and this power is used to charge battery 5401. Additionally, by including multiple batteries in the ICD body 5400, safety can be improved. Specifically, even if some batteries in the ICD body 5400 fail, the other batteries can function and be used as auxiliary power.

[0409] In addition to the antenna 5404, which can receive power, it may also include an antenna capable of transmitting physiological signals. For example, it may also constitute a system for monitoring cardiac activity that can be confirmed by an external monitoring device with physiological signals such as pulse, respiratory rate, heart rate, and body temperature.

[0410] [computer]

[0411] Figure 25A The computer 5600 shown is an example of a mainframe computer. In computer 5600, multiple rack-mounted computers 5620 are housed in rack 5610.

[0412] Computer 5620, for example, can have Figure 25B The structure shown in the 3D diagram. In Figure 25B In the computer 5620, a motherboard 5630 is included, which includes multiple slots 5631 and multiple connection terminals. A personal computer card 5621 is inserted into the slots 5631. The personal computer card 5621 includes connection terminals 5623, 5624, and 5625, which are connected to the motherboard 5630.

[0413] Figure 25CThe personal computer card 5621 shown is an example of a processing board including a CPU, GPU, storage device, etc. The personal computer card 5621 has a board 5622. Furthermore, the board 5622 includes connection terminals 5623, 5624, and 5625, semiconductor devices 5626, 5627, and 5628, and a connection terminal 5629. Note that... Figure 25C Semiconductor devices other than semiconductor devices 5626, 5627 and 5628 are shown. For a description of these semiconductor devices, please refer to the description of semiconductor devices 5626, 5627 and 5628 described below.

[0414] The connection terminal 5629 has a shape that allows it to be inserted into a slot 5631 on the motherboard 5630. The connection terminal 5629 is used as an interface for connecting the personal computer card 5621 to the motherboard 5630. Examples of specifications for the connection terminal 5629 include PCIe.

[0415] Connection terminals 5623, 5624, and 5625 can be used, for example, as interfaces for powering or inputting signals to the personal computer card 5621. Furthermore, they can be used, for example, as interfaces for outputting signals calculated by the personal computer card 5621. Examples of the specifications for each of connection terminals 5623, 5624, and 5625 include, for example, USB (Universal Serial Bus), SATA (Serial ATA), and SCSI (Small Computer System Interface). Furthermore, when outputting video signals from connection terminals 5623, 5624, and 5625, examples of specifications include HDMI (registered trademark).

[0416] Semiconductor device 5626 includes terminals (not shown) for inputting and outputting signals. By inserting these terminals into a socket (not shown) included in board 5622, semiconductor device 5626 and board 5622 can be electrically connected.

[0417] Semiconductor device 5627 includes multiple terminals, which can be electrically connected to board 5622 by reflow soldering the terminals to wiring provided on board 5622. Examples of semiconductor devices 5627 include FPGA (Field Programmable Gate Array), GPU, CPU, etc. Electronic component 4700, including a storage device according to one aspect of the present invention, can also be used as semiconductor device 5627.

[0418] The semiconductor device 5628 includes a plurality of terminals, which can be electrically connected to the board 5622 by reflow soldering the terminals to wiring provided on the board 5622. Examples of semiconductor devices 5628 include memory devices. For example, electronic components 4700 including a memory device according to one aspect of the present invention can be used as semiconductor devices 5628.

[0419] The Computer 5600 can be used as a parallel computer. By using the Computer 5600 as a parallel computer, large-scale computations required for artificial intelligence learning and inference can be performed, for example.

[0420] By using the storage device according to one aspect of the present invention in the aforementioned various electronic devices, miniaturization, high speed, or low power consumption of the electronic devices can be achieved. Furthermore, the storage device according to one aspect of the present invention has low power consumption, thereby reducing circuit heat generation. This reduces the negative impact of heat generation on the circuit itself, peripheral circuits, and modules. Moreover, by using the storage device according to one aspect of the present invention, electronic devices can operate stably even in high-temperature environments. This improves the reliability of the electronic devices.

[0421] The structure shown in this embodiment can be implemented by appropriately combining it with the structures shown in other embodiments.

[0422] [Symbol Explanation]

[0423] 10: Layer, 20: Layer, 21: Drive circuit, 22: PSW, 23: PSW, 31: Peripheral circuit, 32: Control circuit, 33: Voltage generation circuit, 41: Peripheral circuit, 42: Row decoder, 43: Row driver, 44: Column decoder, 45: Column driver, 47: Input circuit, 48: Output circuit, 100: Storage element.

Claims

1. A storage element comprising: a conductive layer; a magnetic tunnel junction element; and a transistor, wherein the magnetic tunnel junction element is provided overlapping the conductive layer, one of a source electrode and a drain electrode of the transistor is electrically connected to the conductive layer, one of the source electrode and the drain electrode of the transistor has a region over an insulating layer, the other of the source electrode and the drain electrode of the transistor has a region under the insulating layer, and a channel formation region of the transistor has a region along a side surface of the insulating layer.

2. The storage element according to claim 1, wherein a semiconductor layer of the transistor includes an oxide semiconductor.

3. The storage element according to claim 1 or 2, wherein a resistance value of the magnetic tunnel junction element is controlled in accordance with a direction of a current supplied to the conductive layer by the transistor.

4. The storage element according to claim 1, wherein the conductive layer has a region in contact with a semiconductor layer of the transistor.

5. A storage element comprising: a conductive layer; a magnetic tunnel junction element; a first transistor; and a second transistor, wherein the magnetic tunnel junction element is provided overlapping the conductive layer, one of a source electrode and a drain electrode of the first transistor is electrically connected to one of a source electrode and a drain electrode of the second transistor at least through a region of the conductive layer overlapping the magnetic tunnel junction element, one of the source electrode and the drain electrode of the first transistor has a region over an insulating layer, the other of the source electrode and the drain electrode of the first transistor has a region under the insulating layer, a channel formation region of the first transistor has a region along a first side surface of the insulating layer, one of the source electrode and the drain electrode of the second transistor has a region over the insulating layer, the other of the source electrode and the drain electrode of the second transistor has a region under the insulating layer, and a channel formation region of the second transistor has a region along a second side surface of the insulating layer.

6. The storage element according to claim 5, wherein a semiconductor layer of the first transistor includes an oxide semiconductor, and a semiconductor layer of the second transistor includes an oxide semiconductor.

7. The storage element according to claim 5 or 6, wherein a resistance value of the magnetic tunnel junction element is controlled in accordance with a direction of a current supplied to the conductive layer by the first transistor or the second transistor.

8. The storage element according to claim 5, wherein the conductive layer has a region in contact with a semiconductor layer of the first transistor and has a region in contact with a semiconductor layer of the second transistor. ​ ​

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