Semiconductor device

Abstract

To provide a semiconductor device capable of changing a storage area of each hierarchy of a storage device.SOLUTION: In a semiconductor device including a memory device including first and second memory circuits and a control circuit, the first memory circuit includes a first capacitor and a first transistor having a function of retaining charge retained in the first capacitor, and the second memory circuit includes a second transistor, a second capacitor electrically connected to a gate of the second transistor, and a third transistor having a function of retaining charge retained in the second capacitor. Each of the first and third transistors includes a semiconductor layer including an oxide semiconductor, a gate, and a back gate. The voltage applied to the first or third transistor back gate is adjusted to change the respective storage area of the first or second storage circuit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] One embodiment of the present invention relates to a semiconductor device.

[0002] Note that one embodiment of the present invention is not limited to the above technical fields. The technical field of one aspect of the present invention relates to an article, a method, or a manufacturing method. One aspect of the invention is a process, machine, manufacture, or composition of matter. Another embodiment of the present invention relates to a semiconductor device, a display device, device, light emitting device, power storage device, storage device, driving method thereof, or manufacturing method thereof do. [Background technology]

[0003] A wide variety of configurations have been proposed for computer systems that process information, depending on their applications. However, in many computer systems, memory units are divided into multiple hierarchies. The architecture uses storage devices with different performance levels assigned to each layer. In such a computer system, registers, cache memory, main memory, auxiliary memory, Structures including storage devices, such as memory devices, are widely known.

[0004] Patent Document 1 discloses a memory circuit using a transistor including an oxide semiconductor in a semiconductor layer. The invention is disclosed as being applied to a memory, a cache memory, and a main memory device. It has a wider band gap than silicon and a lower intrinsic carrier concentration, making it suitable for oxide semiconductors. A transistor including a conductor in a semiconductor layer has the characteristic of having an extremely small off-state current. By using the transistor in a memory circuit, stored data can be retained for a long time. It is possible. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-180994 Summary of the Invention [Problem to be solved by the invention]

[0006] The required performance of each memory device, such as registers, cache memory, and main memory, is Therefore, it is difficult to share the storage area between them. When the storage capacity of the cache memory is insufficient, the main memory makes up for the shortage. It is difficult to make up for this.

[0007] An object of one embodiment of the present invention is to provide a novel semiconductor device. Another object of the present invention is to provide a semiconductor device that can reduce power consumption. Another object of the present invention is to provide a semiconductor device whose area can be reduced. One of the objects of the present invention is to provide a semiconductor device that can increase the capacity of a memory device.

[0008] Note that one embodiment of the present invention does not necessarily have to solve all of the above problems, but It is sufficient if the invention can solve at least one of the problems. Problems other than these cannot be identified from the description, drawings, claims, etc. It will be obvious from the description, drawings, claims, etc. that there are other issues. It is possible to extract [Means for solving the problem]

[0009] (1) One aspect of the present invention is a storage device that operates in a first storage hierarchy and a control circuit. and a second memory circuit operating in a second memory hierarchy, the first memory hierarchy comprising: The first storage circuit is a layer having a faster access speed than the second storage layer, and the first storage circuit includes a first capacitance element and a first transistor having a function of holding charge held in the first capacitance element, The second memory circuit includes a second transistor and a gate of the second transistor. a second capacitance element; and a third transistor having a function of retaining the charge retained in the second capacitance element. the first and third transistors each include a semiconductor layer having an oxide semiconductor and a first a first gate and a second gate, and a control circuit applies a voltage to the second gate of the first transistor. By inputting the command, the first memory circuit is changed from the first memory hierarchy to the second memory hierarchy. By inputting a voltage to the second gate of the third transistor, the second memory circuit is and a function of changing the memory hierarchy from the first memory hierarchy to the second memory hierarchy.

[0010] (2) In addition, one aspect of the present invention is the configuration (1) above, wherein the control circuit has a temperature detection circuit. The temperature detection circuit has a function of outputting a correction voltage according to the temperature around the storage device. The control circuit adjusts the voltages applied to the second gates of the first and third transistors by a correction voltage. It is a semiconductor device that has the function of changing the voltage depending on the pressure.

[0011] (3) Another embodiment of the present invention is a memory device including a first memory layer and a control circuit. a first memory circuit operating in a layer and a second memory circuit operating in a second memory layer, The first storage layer is a layer having a faster access speed than the second storage layer, and the first storage circuit is a first capacitance a first transistor having a function of retaining the charge retained in the first capacitance element; the second memory circuit includes a second transistor and a gate of the second transistor electrically connected to the second memory circuit; a second capacitance element connected to the second capacitance element; and a third transistor having a function of retaining the charge retained in the second capacitance element. the first and third transistors have a semiconductor layer including an oxide semiconductor; , a first gate, and a second gate, and the control circuit controls the second gate of the first transistor. By inputting a voltage, the first memory circuit is changed from the first memory hierarchy to the second memory hierarchy. and a second memory circuit, by inputting a voltage to the second gate of the third transistor. from the second storage hierarchy to the first storage hierarchy, and the control circuit has a function of a plurality of voltage generating circuits and a switching circuit, and the storage device is The controller has a function of outputting a signal indicating the usage status of the storage capacity of the storage device. In response to the signal, a voltage output from one of the plurality of voltage generating circuits is selected from the first and third The switching circuit has a function of controlling the voltage applied to the second gate of the transistor. , a semiconductor device.

[0012] (4) In addition, one aspect of the present invention is the configuration (3) above, wherein the control circuit has a temperature detection circuit. The temperature detection circuit has a function of outputting a correction voltage according to the temperature around the storage device. The control circuit adjusts the voltages applied to the second gates of the first and third transistors by a correction voltage. It is a semiconductor device that has the function of changing the voltage depending on the pressure.

[0013] (5) Another embodiment of the present invention is a memory device including a first memory layer and a control circuit. a first memory circuit operating in a layer and a second memory circuit operating in a second memory layer, The first storage layer is a layer having a faster access speed than the second storage layer, and the first storage circuit is a first capacitance a first transistor having a function of retaining the charge retained in the first capacitance element; the second memory circuit includes a second transistor and a gate of the second transistor electrically connected to the second memory circuit; a second capacitance element connected to the second capacitance element; and a third transistor having a function of retaining the charge retained in the second capacitance element. the first and third transistors have a semiconductor layer including an oxide semiconductor; , a first gate, and a second gate, and the control circuit controls the second gate of the first transistor. By inputting a voltage, the first memory circuit is changed from the first memory hierarchy to the second memory hierarchy. and a second memory circuit, by inputting a voltage to the second gate of the third transistor. from the second storage hierarchy to the first storage hierarchy, and the control circuit has a function of a plurality of voltage generating circuits and a switching circuit, and the storage device is The controller has a function of outputting a signal indicating the usage status of the storage capacity of the storage device. In response to the signal, a voltage output from one of the plurality of voltage generating circuits is selected from the first and third a function of controlling the switching circuit so that a voltage is applied to the second gate of the transistor; The first memory circuit is a semiconductor device having a region overlapping with the second memory circuit.

[0014] (6) In addition, one aspect of the present invention is the configuration (5) above, wherein the control circuit has a temperature detection circuit. The temperature detection circuit has a function of outputting a correction voltage according to the temperature around the storage device. The control circuit adjusts the voltages applied to the second gates of the first and third transistors by a correction voltage. It is a semiconductor device that has the function of changing the voltage depending on the pressure.

[0015] (7) In addition, one embodiment of the present invention is a method for manufacturing a semiconductor device according to any one of the above structures (1) to (6), wherein an oxide Semiconductors are made of indium, element M (element M can be aluminum, gallium, yttrium, or The semiconductor device has one or more materials selected from the group consisting of tin, zinc, and the like.

[0016] In this specification, a semiconductor device is a device that utilizes semiconductor characteristics. Circuits containing semiconductor elements (transistors, diodes, photodiodes, etc.) It also refers to any device that can function by utilizing the properties of semiconductors. For example, Integrated circuits, chips with integrated circuits, and electronic components that house chips in packages are semiconductors. In addition, a storage device, a display device, a light-emitting device, a lighting device, an electronic device, etc. It may itself be a semiconductor device and may contain a semiconductor device.

[0017] In addition, in this specification, when it is stated that X and Y are connected, it means that X and Y are connected. When X and Y are electrically connected, when X and Y are functionally connected, and when X and The case where Y is directly connected is also considered to be disclosed in this specification. Therefore, the present invention is not limited to predetermined connection relationships, for example, connection relationships shown in drawings or text, but may be applied to connections shown in drawings or text. Connections other than those shown in the figure or text are also considered to be disclosed. The object (e.g., device, element, circuit, wiring, electrode, terminal, conductive film, layer, etc.) .

[0018] An example of the case where X and Y are electrically connected is The elements that function as One or more diodes, display elements, light-emitting elements, loads, etc.) are connected between X and Y. The switch has a function to control on / off. A switch can be in a conducting state (ON state) or a non-conducting state (OFF state), allowing current to flow. It has a function to control whether or not water is flushed.

[0019] An example of a case where X and Y are functionally connected is when the functional connection between X and Y is possible. Circuits that perform functions (e.g., logic circuits (inverters, NAND circuits, NOR circuits, etc.)), signal Conversion circuits (DA conversion circuits, AD conversion circuits, gamma correction circuits, etc.), potential level conversion circuits ( Power supply circuits (boost circuits, step-down circuits, etc.), level shifter circuits that change the signal potential level, etc. ), voltage source, current source, switching circuit, amplifier circuit (which can increase the signal amplitude or current amount, etc.) circuits, operational amplifiers, differential amplifier circuits, source follower circuits, buffer circuits, etc.), signal generation One or more circuits (e.g., memory circuits, control circuits, etc.) can be connected between X and Y. For example, even if another circuit is inserted between X and Y, the signal output from X X and Y are said to be functionally connected if X is transmitted to Y.

[0020] When it is explicitly stated that X and Y are electrically connected, it means that X and Y are electrically connected. When X and Y are electrically connected (i.e., when another element or circuit is inserted between X and Y) X and Y are functionally connected (i.e., there is no connection between X and Y) When X and Y are connected directly, the two are functionally connected via another circuit. (i.e., when X and Y are connected without any other element or circuit between them) In other words, when it is explicitly stated that something is electrically connected, it is not simply is the same as if it were expressly stated only that it is connected to

[0021] Also, for example, "X and Y and the source (or first terminal, etc.) and drain ( or the second terminal, etc.) are electrically connected to each other, and X is the source of the transistor (or first terminal, etc.), the drain (or second terminal, etc.) of the transistor, and Y in that order. It can be expressed as "electrically connected to the source ( or the first terminal) is electrically connected to X, and the drain (or second terminal, etc.) is electrically connected to Y, and X, the source (or first terminal, etc.) of the transistor. , the drain (or second terminal, etc.) of the transistor, Y, are electrically connected in this order. Alternatively, "X is the source (or first terminal) of the transistor." The transistor is electrically connected to Y through the drain (or second terminal, etc.) and the transistor is electrically connected to X. The source (or first terminal, etc.) of the transistor, the drain (or second terminal, etc.) of the transistor (e.g., Y is provided in this connection order). By using a similar expression method to specify the order of connections in a circuit configuration, The source (or first terminal, etc.) and drain (or second terminal, etc.) of the transistor are connected to each other. The technical scope can be determined by distinguishing between the two. Note that these methods of expression are merely examples. , and is not limited to these representation methods. Here, X, Y, Z1, and Z2 are the coordinates of the object (e.g., device, element, circuit, wiring, electrode, terminal, conductive film, layer, etc.

[0022] Note that the circuit diagram shows independent components as if they are electrically connected to each other. Even if one component has the functions of multiple components, For example, when a part of the wiring also functions as an electrode, one conductive film functions as both the wiring and the electrode. Therefore, the present invention has the functions of both the electrode and the electrode. Electrical connection means that one conductive film has the functions of multiple components. This case will also be included in that category.

[0023] In this specification, a transistor is referred to as a gate, a source, and a drain. The gate is a control terminal that controls the conduction state of the transistor. The two terminals that function as the source and drain are the input and output terminals of the transistor. The two input / output terminals are used to select the transistor conductivity type (n-channel, p-channel) and the transistor Depending on the potential applied to the three terminals of the transistor, one becomes the source and the other becomes the drain. Therefore, in this specification and the like, the terms source and drain can be interchanged. In addition, in this specification and the like, when describing the connection relationship of a transistor, "One of the source and drain" (or first electrode, or first terminal), "the source or drain The term "second electrode" or "second terminal" is used. In some cases, a back gate may be provided in addition to the three terminals described above.

[0024] In this specification, a node may be a terminal, a wiring, or the like depending on a circuit configuration, a device structure, or the like. It can be called a line, an electrode, a conductive layer, a conductor, an impurity region, etc. Wiring and the like can be called nodes in other words.

[0025] In addition, in this specification, the terms "voltage" and "potential" can be interchanged as appropriate. "Voltage" refers to the potential difference from a reference potential. For example, If we consider the ground potential as the earth potential, we can change the word "voltage" to "potential." The potential does not necessarily mean 0V. Note that the potential is relative and the reference Depending on the potential, the potential applied to the wiring etc. may be changed.

[0026] Generally, "electric current" is the phenomenon of charge transfer (electrical conduction) that accompanies the movement of positively charged bodies. However, the statement "electrical conduction of positively charged bodies is occurring" does not necessarily mean "the opposite direction" In other words, "electrical conduction of negatively charged bodies occurs in the In this document, unless otherwise specified, "current" refers to the phenomenon of charge movement (electric current) that accompanies the movement of carriers. The carriers referred to here are electrons, holes, anions, and cations. , complex ions, etc., and in systems where current flows (e.g., semiconductors, metals, electrolytes, vacuum, etc.) ) The carriers differ depending on the direction of the current. In addition, the direction of the current in wiring etc. is The direction of movement of negative carriers is expressed as a positive current amount. , the direction is opposite to the direction of the current and is expressed as a negative current amount. Therefore, unless there is a specification as to whether the current is positive or negative (or the direction of the current), it is assumed that "current flows from element A to element B." A statement such as "current flows from element B to element A" can be rephrased as "current flows from element B to element A" Furthermore, statements such as "current is input to element A" should be interpreted as "current is output from element A." This can be rephrased as "can be" or "can be used for other purposes."

[0027] In addition, in this specification, the ordinal numbers "first," "second," and "third" are used to indicate constituent elements. Therefore, it does not limit the number of components. In addition, the order of the components is not limited. The element referred to as "first" in the above may be used in other embodiments or in the claims. In addition, for example, in the present specification, A component referred to as "first" in one embodiment may be used in other embodiments or in particular It may be omitted within the scope of the claims.

[0028] In addition, in this specification, terms indicating arrangement such as "above" and "below" refer to the relationship between components. The positional relationship may be used for convenience in explaining the configuration with reference to the drawings. The positional relationship between the elements changes depending on the direction in which each element is depicted. The terms are not limited to those explained in the detailed instructions, but can be rephrased appropriately depending on the situation. For example, the expression "insulator on top of conductor" means that the orientation of the drawing shown is rotated 180 degrees. By turning it around, it can be rephrased as "an insulator located on the underside of a conductor."

[0029] In addition, the terms "above" and "below" refer to the positional relationship of the components directly above or below and directly connected to each other. For example, if the expression is "electrode B on insulating layer A," The electrode B does not need to be formed directly on the insulating layer A, and the insulating layer A and the electrode B This does not exclude the inclusion of other components in between.

[0030] In addition, in this specification and the like, the terms "film" and "layer" may be used interchangeably depending on the situation. For example, the term "conductive layer" can be changed to the term "conductive film." Or, for example, the term "insulating film" may be changed to "insulating layer." In some cases, or depending on the circumstances, it may be possible to change the term to " For example, terms such as "film" and "layer" can be omitted and replaced with other terms. For example, the term "conductive layer" or "conductive film" may be changed to the term "conductor." Or, for example, the terms "insulating layer" and "insulating film" may be changed to "insulator." It may be possible to change the term to something like this.

[0031] In addition, the terms "electrode" and "wiring" used in this specification and the like refer to these components functionally. This is not a limitation. For example, an "electrode" may be used as part of a "wiring." , and vice versa. Furthermore, the terms "electrode" and "wiring" may be used interchangeably with "electrodes" and "wiring." This also includes cases where the wiring is formed integrally.

[0032] In addition, in this specification, terms such as "wiring," "signal line," and "power line" may be used interchangeably. Depending on the situation, they can be interchanged. For example, "wiring" It may be possible to change the term to "signal line". In some cases, it may be possible to change the term "wiring" to a term such as "power line." The reverse is also true; terms such as "signal line" and "power line" should be changed to "wiring." It may be possible to change terms such as "power line" to terms such as "signal line." In addition, the reverse is also true, and terms such as "signal line" may be used interchangeably with "power line" In some cases, it may be possible to change the term to something like "potential" applied to the wiring. In some cases or depending on the situation, the term "signal" may be changed to "signal" or similar. And vice versa, terms such as "signal" can be used to refer to "potential." It may be possible to change the term.

[0033] In this specification, impurities in a semiconductor are, for example, substances other than the main components constituting a semiconductor layer. For example, elements with a concentration of less than 0.1 atomic percent are considered impurities. This can result in the formation of DOS (Density of States) in semiconductors. In some cases, the carrier mobility may decrease, or the crystallinity may decrease. When the semiconductor is an oxide semiconductor, impurities that change the properties of the semiconductor include, for example, , Group 1 elements, Group 2 elements, Group 13 elements, Group 14 elements, Group 15 elements, other than the main component Transition metals, especially hydrogen (which is also contained in water), lithium, sodium, Silicon, boron, phosphorus, carbon, nitrogen, etc. In the case of oxide semiconductors, for example, hydrogen The inclusion of impurities can cause oxygen vacancies. In this case, impurities that change the properties of semiconductors include, for example, oxygen and Group 1 elements excluding hydrogen. , Group 2 elements, Group 13 elements, Group 15 elements, etc.

[0034] In this specification, a switch is a device that can be in a conducting state (ON state) or a non-conducting state (OFF state). It is a device that has the function of controlling whether or not current flows by entering a state where it is in a switched state. A switch is a device that has the function of selecting and switching the path through which current flows. , electrical switches, mechanical switches, etc. can be used. The device is not limited to a specific one as long as it can control the current.

[0035] An example of an electrical switch is a transistor (e.g., a bipolar transistor, MOS transistors, etc.), diodes (e.g., PN diodes, PIN diodes, Schottky diode, MIM (Metal Insulator Metal) die MIS (Metal Insulator Semiconductor) die diode-connected transistors, etc.), or logic circuits that combine these When using a transistor as a switch, the "conduction state" of the transistor This means that the source and drain electrodes of the transistor are considered to be electrically short-circuited. The "non-conducting state" of a transistor refers to the state in which the source electrode and drain electrode of the transistor are in a non-conducting state. This refers to a state in which the input electrode can be considered to be electrically disconnected. When operating as a switch, the polarity (conductivity type) of the transistor is not particularly limited.

[0036] An example of a mechanical switch is a digital micromirror device (DMD). In 2013, a switch using MEMS (microelectromechanical systems) technology was developed. The switch has a mechanically movable electrode, and when the electrode moves, Therefore, the device operates by controlling conduction and non-conduction. [Effects of the Invention]

[0037] According to one aspect of the present invention, a novel device can be provided. As a result, a semiconductor device capable of reducing power consumption can be provided. According to one embodiment, a semiconductor device whose area can be reduced can be provided. According to one embodiment, a semiconductor device capable of increasing the capacity of a storage device can be provided.

[0038] The description of these effects does not preclude the existence of other effects. An embodiment does not necessarily have to have all of these effects. The above will be made clear from the description, drawings, claims, etc. It is possible to extract other effects from the descriptions in the aspects and claims. [Brief explanation of the drawings]

[0039] [Figure 1] Fig. 1(A) is a block diagram showing an example of the configuration of a storage device, and Fig. 1(B) is a diagram illustrating an example of the hierarchy of storage areas in the storage device. [Figure 2] FIG. 2 is a diagram illustrating an example of a hierarchy of storage areas in a storage device. [Figure 3] 3A, 3B, and 3C are circuit diagrams showing examples of the configuration of a memory cell included in a memory device. [Figure 4] 4A and 4B are diagrams illustrating an example of a hierarchy of storage areas in a storage device. [Figure 5] FIG. 5 is a block diagram showing an example of the configuration of a storage device. [Figure 6] FIG. 6 is a block diagram showing an example of the configuration of a storage device. [Figure 7]FIG. 7 is a block diagram showing an example of the configuration of a storage device. [Figure 8] FIG. 8 is a block diagram showing an example of the configuration of a storage device. [Figure 9] FIG. 9 is a block diagram showing an example of the configuration of a storage device. [Figure 10] FIG. 10 is a block diagram showing an example of the configuration of a memory cell array included in a storage device. [Figure 11] FIG. 11 is a block diagram showing an example of the configuration of a memory cell array included in a storage device. [Figure 12] 12A and 12B are diagrams showing an example of the configuration of a memory cell array included in a memory device. [Figure 13] FIG. 13 is a diagram showing an example of the configuration of a memory cell array included in a memory device. [Figure 14] FIG. 14 is a cross-sectional view showing an example of the configuration of a semiconductor device. [Figure 15] 15(A), (B), and (C) are cross-sectional views showing examples of the structure of a transistor. [Figure 16] FIG. 16A is a top view illustrating a structural example of a transistor, and FIGS. 16B and 16C are cross-sectional views illustrating the structural example of the transistor. [Figure 17] FIG. 17A is a top view illustrating a structural example of a transistor, and FIGS. 17B and 17C are cross-sectional views illustrating the structural example of the transistor. [Figure 18] FIG. 18A is a top view illustrating a structural example of a transistor, and FIGS. 18B and 18C are cross-sectional views illustrating the structural example of the transistor. [Figure 19] FIG. 19A is a top view illustrating a structural example of a transistor, and FIGS. 19B and 19C are cross-sectional views illustrating the structural example of the transistor. [Figure 20] FIG. 20A is a top view illustrating a structural example of a transistor, and FIGS. 20B and 20C are cross-sectional views illustrating the structural example of the transistor. [Figure 21] FIG. 21A is a top view illustrating a structural example of a transistor, and FIG. 21B is a perspective view illustrating the structural example of the transistor. [Figure 22] 22(A) and 22(B) are cross-sectional views showing examples of the structure of a transistor. [Figure 23] 23(A), (B), (C), (D), (E), (F), (G), and (H) are perspective views showing examples of electronic devices. [Figure 24] 24(A) and 24(B) are perspective views showing an example of an electronic device. DETAILED DESCRIPTION OF THE INVENTION

[0040] In this specification, the term "metal oxide" refers to a metal in a broad sense. Metal oxides are oxides of the following: oxide insulators, oxide conductors (including transparent oxide conductors), ), oxide semiconductors (also called oxide semiconductors or simply OS), For example, when a metal oxide is used in the active layer of a transistor, the metal oxide In other words, metal oxides have amplifying, rectifying, and and forming a channel forming region of a transistor having at least one of a switching function and a If possible, the metal oxide is referred to as a metal oxide semiconductor. It can also be called an OS FET or OS transistor. In the above description, the transistor is referred to as a transistor including a metal oxide or an oxide semiconductor. It is possible.

[0041] In this specification and the like, metal oxides containing nitrogen are also referred to as metal oxides (metal ox). Metal oxides containing nitrogen are sometimes collectively called metal oxynitrides (metal oxynitrides). It may also be called tal oxynitride.

[0042] In addition, in this specification and the like, the configurations shown in each embodiment may be interchangeable with the configurations shown in other embodiments. The above-described embodiments can be combined appropriately to form one aspect of the present invention. When multiple configuration examples are shown, the configuration examples can be combined with each other as appropriate.

[0043] It should be noted that the contents (or even a part of the contents) described in one embodiment may be used in the implementation of the embodiment. Another content (or a part of the content) described in the embodiment and one or more other embodiments ( or one or more other embodiments) (or a part of the contents) The content can be applied, combined, or replaced with another content.

[0044] The contents described in the embodiments refer to the following in each embodiment (or example): The content described using various figures or the text in the specification be.

[0045] In addition, a drawing (or a part thereof) described in one embodiment may be replaced with another part of the drawing. In the embodiment, another figure (or a part thereof) and one or more other embodiments may be used. At least one of the drawings (or a part thereof) described in the embodiment is combined with By adding more, more figures can be constructed.

[0046] The embodiments described in this specification are explained with reference to the drawings. The present invention may be embodied in many different forms without departing from the spirit and scope thereof. It will be readily understood by those skilled in the art that various changes in form and details can be made without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiment. In the configuration of the invention of the embodiment, the same parts or parts having similar functions are designated by the same reference numerals. The same elements are used in different drawings, and repeated explanations may be omitted. In some cases, in order to ensure clarity of the drawings, some components may be omitted. be.

[0047] Also, in the drawings of this specification, the size, layer thickness, or area may be exaggerated for clarity. Therefore, the drawings are not necessarily limited to the scale. The drawings are merely conceptual examples, and are not limited to the shapes or values ​​shown in the drawings. For example, variations in signal, voltage, or current due to noise, or timing errors This can include variations in signal, voltage, or current.

[0048] (Embodiment 1) In this embodiment, a structure example according to one embodiment of the present invention will be described.

[0049] <Configuration example of semiconductor device> FIG. 1A illustrates an example of the structure of a semiconductor device 11 according to one embodiment of the present invention. The memory device includes a memory circuit 210, a memory circuit 220, a memory circuit 230, and a memory circuit 240 and a control circuit 20.

[0050] Although not shown in FIG. 1A, the semiconductor device 11 may include an integrated circuit (e.g., a CPU, The memory circuit 210 is included in an integrated circuit. Furthermore, the memory circuit 220 may also be included in the integrated circuit.

[0051] The memory circuit 220 is a DOSRAM (Dynamic Oxide Semiconductor Conductor Random Access Memory (registered trademark) The memory circuit 230 can be implemented using NOSRAM (Dynamic Oxide Semiconductor Memory). Conductor Random Access Memory (registered trademark) is applied Details of DOSRAM and NOSRAM will be explained later.

[0052] FIG. 1B shows a memory circuit of a memory device included in the semiconductor device 11 shown in FIG. 1A in a tiered manner. FIG. 1 is a diagram showing an example for each layer.

[0053] FIG. 1B shows the memory circuits of the memory device included in the semiconductor device 11, sorted in order of access speed. The memory circuit 210 is the highest layer, and the memory circuit 220 is the The memory circuit 230 is a lower layer than the memory circuit 220, and the memory circuit 240 is shown as the lowest layer.

[0054] In this specification, the memory circuit of the memory device included in the semiconductor device 11 is the highest In order from the hierarchical level, the first storage area 110, the second storage area 120, the third storage area 130, the fourth storage area 140, The first memory area 110 is a memory area for registers, etc. The second storage area 120 is a storage area of ​​a cache memory, and the third storage area 130 is a storage area of ​​a main memory. The fourth storage area 140 is a storage area of ​​the auxiliary storage device. It is treated as such.

[0055] The memory circuit 210 in the first memory area 110 stores the results and status of arithmetic processing in an integrated circuit or the like. Therefore, the memory circuit 21 is used to transmit and receive data required for the calculation process. 0 is electrically connected to the memory circuit 220 and the memory circuit 230.

[0056] The memory circuit 210 applicable to the first memory area 110 is, for example, a register, a flip-flop, or the like. It has chips, SRAM (Static Random Access Memory), etc. do.

[0057] The second storage area 120 is treated as a storage area of ​​the cache memory, so that the storage circuit 2 20 receives data from the memory circuit 230 that functions as the main memory device, which is the third memory area 130. is electrically connected to a memory circuit 230 for storing a copy of a portion of the data.

[0058] In addition, since the second storage area 120 corresponds to the storage area of ​​the cache memory, The area 120 can be further divided into multiple layers. For example, in FIG. The memory circuit 220 in FIG. The first storage area 110 has a storage area of ​​a cache 121 to a cache 123. A cache 121 (primary cache, L1 cache) is provided at the upper level. A cache 122 (secondary cache, L2 cache) is provided at a lower level of the memory 121. The cache 122 has a lower level cache 123 (third level cache, L3 cache). A public restroom is provided.

[0059] The number of layers in the second storage area 120 is not limited to this. 20 may consist of only one floor, two floors, or four or more floors. It may be made up of layers.

[0060] The memory circuit 240 applicable to the fourth memory area 140 is the memory circuit 230 of the third memory area. The input data is electrically connected to a memory circuit 230 for storing the input data.

[0061] The memory circuit 240 applicable to the fourth memory area 140 is, for example, a nonvolatile memory. The nonvolatile memory may include, for example, a flash memory, a hard disk drive, etc. Examples include disk drives and solid-state drives.

[0062] The control circuit 20 is electrically connected to the memory circuit 220 and the memory circuit 230. The control circuit 20 is a second memory area 120 and a third memory area 130 in the semiconductor device 11. It has the function to change the storage area of ​​each layer.

[0063] The higher the layer in which a memory circuit is located, the faster it is required to operate. The more memory devices are deployed, the greater the capacity and density (or the smaller the area per bit) required. For example, the first storage area 110 stores data used for calculations in an integrated circuit or the like. In addition, for example, in the second storage area 120, The first-level cache, which is located at the top of the hierarchy, is accessed most frequently and therefore has high speed. On the other hand, the second and third level caches are required to operate as fast as the first level cache. Although high speed is not required, it has a large capacity and more bits per second than the primary cache. A reduction in area is required.

[0064] In addition, the higher the hierarchy of a memory circuit, the greater the number of times data is rewritten to the memory device. (or refresh frequency) will increase, so the specifications of the storage device On the other hand, the lower the hierarchy of a storage device, the more time it takes to The number of times of rewriting data (or the number of refresh times) to the storage device is reduced, so it is necessary to increase the data holding time as the specification of the storage device. As the specification of the storage device, it is necessary to increase the data holding time.

[0065] One aspect of the present invention changes the data holding time of each hierarchical storage device according to the usage situation of the semiconductor device, and increases or decreases the storage area of each hierarchy. That is, the storage device or semiconductor device according to one aspect of the present invention can change the performance of each hierarchy of the storage device according to the usage situation. Next, the circuit configurations of the memory cells of DOSRAM applicable to the memory circuit 220 and NOSRAM applicable to the memory circuit 230 will be described. It can be done. That is, the storage device or semiconductor device according to one aspect of the present invention can change the performance of each hierarchy of the storage device according to the usage situation.

[0066] <Circuit configuration examples of DOSRAM and NOSRAM> Next, the circuit configurations of the memory cells of DOSRAM applicable to the memory circuit 220 and NOSRAM applicable to the memory circuit 230 will be described. That is, the storage device or semiconductor device according to one aspect of the present invention can change the performance of each hierarchy of the storage device according to the usage situation.

[0067] In addition, the low-level potential and high-level potential used in the following description do not mean specific potentials, and if the wiring is different, the specific potentials may also be different. For example, the low-level potential and high-level potential applied to the wiring WOL may be different from the low-level potential and high-level potential applied to the wiring BIL. In addition, the low-level potential and high-level potential used in the following description do not mean specific potentials, and if the wiring is different, the specific potentials may also be different. For example, each of the low-level potential and high-level potential applied to the wiring WOL may be a potential different from the low-level potential and high-level potential applied to the wiring BIL. In addition, the low-level potential and high-level potential used in the following description do not mean specific potentials, and if the wiring is different, the specific potentials may also be different. For example, each of the low-level potential and high-level potential applied to the wiring WOL may be a potential different from the low-level potential and high-level potential applied to the wiring BIL. That is, the low-level potential and high-level potential applied to the wiring WOL may be different from the low-level potential and high-level potential applied to the wiring BIL.

[0068] FIG. 3(A) shows an example of the circuit configuration of the memory cell of DOSRAM. The memory cell 221 has a transistor M1 and a capacitive element CA. The transistor M1 has a front gate (which may be simply called a gate) and a back gate. The memory cell 221 has a transistor M1 and a capacitive element CA. The transistor M1 has a front gate (which may be simply called a gate) and a back gate. The transistor M1 has a front gate (which may be simply called a gate) and a back gate.

[0069] The first terminal of the transistor M1 is connected to the first terminal of the capacitive element CA, the second terminal of the transistor M1 is connected to the wiring BIL, and the gate of the transistor M1 is connected to the wiring WOL. The first terminal of the transistor M1 is connected to the first terminal of the capacitive element CA, the second terminal of the transistor M1 is connected to the wiring BIL, and the gate of the transistor M1 is connected to the wiring WOL. The back gate of the transistor M1 is connected to the wiring BGL. The second terminal of A is connected to the wiring CAL.

[0070] Transistor M1 functions as a write transistor in memory cell 221. The write transistor is preferably an OS transistor, which will be described later. .

[0071] The wiring BIL functions as a bit line, and the wiring WOL functions as a word line. CAL functions as a wiring for applying a predetermined potential to the second terminal of the capacitive element CA. When writing and reading data, the CAL line is connected to a low-level potential (reference potential). It is preferable to apply a voltage of 0.1 V.

[0072] The wiring BGL functions as a wiring for applying a potential to the back gate of the transistor M1. By applying an arbitrary potential to the wiring BGL, the threshold voltage of the transistor M1 The voltage can be increased or decreased.

[0073] Data is written and read by applying a high-level potential to the wiring WOL and M1 is turned on, and a state of conduction is established between the wiring BIL and the first terminal of the capacitance element CA. This is done by:

[0074] Specifically, data is written by applying a potential corresponding to the data to be written to the wiring BIL. This is done by writing the potential to the first terminal of the capacitance element CA via the transistor M1. After writing the data, a low-level potential is applied to the wiring WOL to turn on the transistor M1. By turning off the potential, the potential can be held in the memory cell 221.

[0075] In addition, to read data, first, the wiring BIL is set to an appropriate potential, for example, a low level potential. and high-level potential, and then the wiring BIL is electrically floating. After that, a high-level potential is applied to the wiring WOL to turn on the transistor M1. The potential of the wiring BIL is changed by turning on the capacitor C Since it is determined by the potential written to the first terminal of A, from the changed potential of the wiring BIL, The data stored in the memory cell 221 can be read out.

[0076] Furthermore, the above-described memory cell 221 is not limited to the circuit configuration shown in FIG. The circuit configuration of memory cell 221 may be changed as appropriate.

[0077] FIG. 3(B1) shows an example of the circuit configuration of a memory cell of NOSRAM. The transistor 231 includes a transistor M2, a transistor M3, and a capacitance element CB. The transistor M2 has a front gate (sometimes simply called a gate) and a back gate. It has a gate.

[0078] Transistor M2 functions as a write transistor in memory cell 231. The write transistor is preferably an OS transistor, which will be described later. .

[0079] Also, transistor M3 functions as a read transistor in memory cell 231. The readout transistor is an OS transistor (described later) or a semiconductor layer having a silicon layer. In this example of operation, the transistor Unless otherwise specified, the transistor M3 operates in the saturation region. The gate voltage, source voltage, and drain voltage of transistor M3 are set to a value within the range in which it operates in the saturation region. It is assumed that the voltage is appropriately biased to

[0080] The first terminal of the transistor M2 is connected to the first terminal of the capacitance element CB, and the transistor M The second terminal of the transistor M2 is connected to the wiring WBL, and the gate of the transistor M3 is connected to the wiring WOL. The back gate of the transistor M2 is connected to the wiring BGL. The second terminal of transistor B is connected to the line CAL. The first terminal of transistor M3 is connected to the line R BL, the second terminal of the transistor M3 is connected to the line SL, and the second terminal of the transistor M The gate of 3 is connected to the first terminal of the capacitance element CB.

[0081] The wiring WBL functions as a write bit line, and the wiring RBL functions as a read bit line. The wiring WOL functions as a word line. The wiring CAL functions as the second wiring of the capacitance element CB. It functions as a wiring for applying a predetermined potential to the terminal. It is preferable to apply a low level potential (sometimes called a reference potential) to the line CAL. When writing data or reading data, a high-level potential is applied to the wiring CAL. It is preferable to

[0082] The wiring BGL functions as a wiring for applying a potential to the back gate of the transistor M2. By applying an arbitrary potential to the wiring BGL, the threshold voltage of the transistor M2 The voltage can be increased or decreased.

[0083] To write data, a high-level potential is applied to the wiring WOL to turn on the transistor M2. This is achieved by bringing the line WBL and the first terminal of the capacitance element CB into a conductive state. Specifically, when the transistor M2 is in an on state, the information to be recorded in the wiring WBL is A corresponding potential is applied to the first terminal of the capacitance element CB and the gate of the transistor M3. After that, a low-level potential is applied to the wiring WOL to turn off the transistor M2. By switching the capacitor CB to the ON state, the potential of the first terminal of the capacitor CB and the potential of the gate of the transistor M3 are The potential is maintained at .

[0084] Data is read by applying a predetermined potential to the line SL. The current flowing between the source and drain of transistor M3 and the potential of the first terminal of transistor M3 is determined by the potential of the gate of the transistor M3 and the potential of the second terminal of the transistor M3. Therefore, the potential of the wiring RBL connected to the first terminal of the transistor M3 is read out. As a result, the voltage is held at the first terminal of the capacitance element CB (or the gate of the transistor M3). That is, the potential at the first terminal of the capacitance element CB (or the transistor The information written in this memory cell can be read from the potential held at the gate of M3. It can be seen.

[0085] Furthermore, the above-described memory cell 231 is not limited to the circuit configuration shown in FIG. 3(B1), The circuit configuration of the memory cell 231 may be changed as appropriate. For example, the wiring WBL and the wiring RBL The memory cell may be configured as a single wiring BIL. 3B2. The memory cell 232 has the wiring WBL and the wiring RBL of the memory cell 231. The second terminal of the transistor M2 and the first terminal of the transistor M3 are connected to one wiring BIL. The terminal is connected to the wiring BIL. The write bit line and the read bit line are configured to operate as a single wiring BIL. It is.

[0086] As mentioned above, DOSRAM and NOSRAM use OS transistors as write transistors. The semiconductor layer of the OS transistor is the same as that described in Embodiment 3. The metal oxide includes, for example, indium, element M (element M is selected from one or more of aluminum, gallium, yttrium, or tin, and zinc; In particular, metal oxides consisting of indium, gallium, and zinc are suitable materials. By being contained in the semiconductor layer, the band gap of the semiconductor layer can be increased. Therefore, the off-state current of the OS transistor can be reduced.

[0087] <How to change the storage area of ​​each tier of a storage device> By the way, the OS transistor can be formed by applying the structure described in Embodiment 3. In the OS transistor having a back gate, By applying a potential to the back gate, the threshold voltage of the OS transistor is varied. For example, when the OS transistor is an n-channel transistor, By applying a positive potential to the back gate, the threshold voltage of the OS transistor Conversely, by applying a negative potential to the back gate, This allows the threshold voltage of the OS transistor to shift to the positive side.

[0088] By varying the threshold voltage of the OS transistor, The off-state current of the OS transistor can be increased or decreased. The charge transfers quickly between the source and drain of the transistor according to the stored data. This shortens the data retention time and increases the operating speed (drive frequency and In addition, the off-state current of the OS transistor can be reduced. When this happens, the voltage across the source and drain of the OS transistor changes depending on the data stored. This slows down the movement of charges, which increases the data retention time and improves the operating speed of the OS transistor. In other words, the threshold voltage of the OS transistor can be changed. This allows the data retention time and operation speed to be adjusted.

[0089] Here, the above-mentioned DOSRAM is applied as the memory circuit 220 of the semiconductor device 11, and the memory circuit Consider the case where the above-mentioned NOSRAM is used as the circuit 230. For example, in FIG. 1(A)(B), In the semiconductor device 11, the storage capacity of the storage circuit 210 used as the first storage area is The memory capacity of the memory circuit 220 used as the second memory area 120 is insufficient, and the memory capacity of the memory circuit 220 is insufficient. In this case, as shown in FIG. 4A, the memory circuit 220a, which is part of the memory circuit 220, has The threshold voltage of the OS transistor in the memory circuit 220a is lowered to shorten the data retention time. By shortening the length and increasing the operating speed, the memory circuit 220a can be made to operate in the first memory area 110. It can be utilized as.

[0090] Specifically, the transistor M1 of the memory cell 221 of the storage circuit 220a is turned on by applying a voltage to the gate. When the applied voltage is in the range of -0.8V to 2.5V, the transistor M For example, a voltage of −1.5 V or more and less than 1.5 V is applied to the back gate of the transistor 1. Thus, the memory circuit 220 a can be utilized as the first memory area 110 .

[0091] In addition, for example, in the semiconductor device 11 of FIGS. 1A and 1B, the third storage area 130 may be The storage capacity of the memory circuit 230 used as the second storage area 120 is insufficient. If the memory circuit 220 has a remaining memory capacity, as shown in FIG. The threshold voltage of the OS transistor included in the memory circuit 220b, which is a part of the memory circuit 220, is increased. Therefore, by lengthening the data retention time of the memory circuit 220b and slowing down the operation speed, The memory circuit 220b can be used as the third memory area 130.

[0092] Specifically, the transistor M1 of the memory cell 221 of the storage circuit 220b is turned on by applying a voltage to the gate. When the applied voltage is in the range of -0.8V to 2.5V, the transistor M For example, a voltage of −7.5 V or more and less than −4.5 V is applied to the back gate of the transistor 1. Therefore, the memory circuit 220 a can be used as the third memory area 130 .

[0093] In the semiconductor device 11 of FIGS. 1A and 1B, the memory area of ​​the memory circuit 220 may be divided into two areas. If the hierarchy is not changed, that is, the storage circuit 220 is used as the second storage area 120 as usual. When operating in this mode, the range of potential applied to the gate of transistor M1 is set to -0.8V or more. The back gate of the transistor M1 is set to, for example, -4.5V or more. A voltage of less than 1.5V is sufficient.

[0094] In addition, for example, in the semiconductor device 11 of FIGS. 1A and 1B, the second storage area 120 may be The storage capacity of the memory circuit 220 used as the third storage area 130 is insufficient. If the memory circuit 230 has a surplus memory capacity, as shown in FIG. The threshold voltage of the OS transistor included in the memory circuit 230a, which is a part of the memory circuit 30, is reduced. By shortening the data retention time of the memory circuit 230a, the memory circuit 230a can be used as a second memory. It can be used as a memory area 120.

[0095] Specifically, the transistor of the memory cell 231 (memory cell 232) of the memory circuit 230a The voltage applied to the gate of the transistor M2 is set to a range of -0.8V to 2.5V. In this case, the back gate of the transistor M2 is set to, for example, -4.5V or more and less than -1.5V. By applying a voltage, the memory circuit 230a can be used as the second memory area 120. can be done.

[0096] In addition, for example, in the semiconductor device 11 of FIGS. 1A and 1B, the fourth storage area 140 may be The storage capacity of the memory circuit 240 used as the third storage area 130 is insufficient. If the memory circuit 230 has a surplus memory capacity, as shown in FIG. The threshold voltage of the OS transistor included in the memory circuit 230b, which is a part of the memory circuit 30, is increased. By lengthening the data retention time of the memory circuit 230b, the memory circuit 230b can be used as a fourth memory. It can be used as a memory area 140.

[0097] Specifically, the transistor of the memory cell 231 (memory cell 232) of the memory circuit 230b The voltage applied to the gate of the transistor M2 is set to a range of -0.8V to 2.5V. In this case, a voltage of, for example, less than −7.5 V is applied to the back gate of the transistor M2. This allows the storage circuit 230b to be used as the fourth storage area 140.

[0098] In the semiconductor device 11 of FIGS. 1A and 1B, the memory area of ​​the memory circuit 230 may be divided into two areas. If the hierarchy is not changed, that is, the storage circuit 230 is used as the third storage area 130 as usual. When operating in this mode, the range of potential applied to the gate of transistor M1 is set to -0.8V or more. The back gate of the transistor M1 is set to, for example, -7.5V or more. Just apply a voltage of less than 4.5V.

[0099] Furthermore, the transistor M1 of the memory cell 221, the memory cell 231 (memory cell 232 ) the range of voltages applied to the gates of the transistors M2 and M3 are approximately the same. Specifically, the gates of the transistors M1 and M2 can be The circuits that generate the positive voltage (or negative voltage) to be applied to the This allows the voltage applied to the gates of the transistors M1 and M2 to be Since it is not necessary to provide a large number of circuits for generating voltages, the power consumption of the semiconductor device 11 can be reduced. In particular, when a negative voltage is applied to the gate of a transistor, the Since the power consumption for generating the voltage can be large, the transistor M1 and the transistor A negative voltage generation circuit (e.g., a charge pump circuit) is used to apply a negative voltage to the gates of M2 and M3. Paths and the like are preferably used in common.

[0100] Incidentally, the gate and back gate of the above-mentioned transistor M1 (transistor M2) The range of voltages applied to the semiconductor device is an example. The characteristics of a transistor change depending on the material and structure of the semiconductor layer of the transistor. Depending on the situation, it is necessary to set the range of voltages to be applied to the gate and back gate.

[0101] In addition, in semiconductor devices in general, transistors are often damaged depending on the environment in which the semiconductor device is operated. Specifically, if the temperature of the environment in which the semiconductor device is operating is high, the characteristics of the semiconductor device may change. The higher the gate-source voltage of the transistor, the larger the drain current. In other words, depending on the environmental temperature, The performance of the semiconductor device may change depending on the temperature of the environment. By changing the voltage applied to the back gate of the OS transistor, which is the write transistor, It is more preferable to use a structure in which the characteristics of the transistor are appropriately adjusted by using the above-mentioned method. That is, the transistors included in the memory cell 221 and the memory cell 231 (memory cell 232) The semiconductor device 11 drives the back gates of the transistors M1 and M2. By applying a voltage according to the temperature of the environment, the memory circuits 220 and 230 Each of them can perform an operation appropriate to the temperature of the environment.

[0102] <Control circuit 20> Next, the write transistors ( Transistor M1 in FIG. 3(A), transistor M2 in FIGS. 3(B1) and 3(B2) The circuit configuration for controlling the threshold voltage of the transistor (corresponding to the transistor (1)) will be described.

[0103] FIG. 5 shows a control circuit 20 for controlling the threshold voltage of the write transistor. 5 is a block diagram showing the electrical connection with the storage device. Also shown is a memory unit 30 including a memory circuit 220 and a memory circuit 230.

[0104] The control circuit 20 includes a control unit 21 and voltage generation circuits 22[1] to 22[P]. (P is an integer equal to or greater than 1), a circuit 23A, a circuit 23B, a temperature detection circuit 25, In addition, when the potential of the back gate is not changed according to the environmental temperature, the control circuit 20 can be configured without the temperature detection circuit 25.

[0105] The control unit 21 includes a storage unit 30, voltage generation circuits 22[1] to 22[P], , and is electrically connected to the circuit 23A, the circuit 23B, and the temperature detection circuit 25. Each of the voltage generating circuits 22[1] to 22[P] includes a circuit 23A and a circuit 23B. The circuit 23A is electrically connected to the memory circuit 220, and the circuit 23B is electrically connected to the memory circuit 23 through a plurality of wirings BGL2. Electrically connected to 0.

[0106] The storage unit 30 stores the usage status of the storage circuit 220 and the storage circuit 230 (for example, The control unit 2 receives a signal indicating the percentage of used storage capacity among the total storage capacity. By receiving the signal, the control unit 21 Depending on the usage state, each layer of the storage unit 30 (for example, the first storage area 11 shown in FIG. 1B) 0, the second storage area 120, the third storage area 130, and the fourth storage area 140. To change the settings, the control circuit 20 sends a signal to each circuit included in the control circuit 20. Specifically, the control 21 includes voltage generation circuits 22[1] to 22[P], a circuit 23A, and a circuit 2 A signal is sent to 3B.

[0107] Each of the voltage generating circuits 22[1] to 22[P] is a write transistor. The voltage generating circuit 22 [1 ] to the voltage generating circuit 22[P] generate the voltage in response to a signal sent from the control unit 21. This function allows the memory unit to start generating the voltage or stop generating the voltage. Only the voltage generation circuit that generates the required voltage for each of the 30 layers is driven. Therefore, the voltage generating circuit 22[1] to the voltage Since only the necessary circuits of the generating circuit 22[P] can be driven, the control circuit 20 The power consumption can be reduced.

[0108] In addition, among the voltage generating circuits 22[1] to 22[P], the negative voltage generating circuits The circuit may be, for example, a charge pump circuit.

[0109] The circuit 23A generates voltages to be applied to the plurality of wirings BGL1 from the voltage generating circuit 22[1 ] to voltage generation circuit 22[P]. The voltage to be selected for each of the multiple wirings BGL1 is determined by a signal sent from the control unit 21. This function determines whether the write transistor included in the memory circuit 220 is A predetermined voltage can be applied to the back gate of the transistor from the wiring BGL1. The circuit 220 can be divided into areas according to the hierarchy to which it is assigned. For example, When 220 is divided into p levels (p is an integer between 2 and P), the circuit 23A is It is sufficient to apply p types of voltages to the wirings BGL1 and divide the memory circuit 220 into p regions. .

[0110] Similarly, the circuit 23B generates voltages to be applied to the plurality of wirings BGL2 by a voltage generating circuit 22[1] to the voltage generation circuit 22[P]. The control unit 2 determines which voltage is selected for each of the multiple wirings BGL2. This function determines the write operation of the memory circuit 230 in accordance with the signal sent from the memory circuit 230. A predetermined voltage can be applied to the back gate of the write transistor from the wiring BGL2. In this case, the memory circuit 230 can be divided into areas according to the hierarchical level to which it is assigned.

[0111] <Example of operation> Here, an example of the operation of the control circuit 20 will be described. Accordingly, a case where the potential of the back gate is not changed will be described.

[0112] In the initial stage of the operation example, for example, the usage state of the storage unit 30 is as shown in FIG. The entire storage capacity of the memory circuit 220 to which the second memory area 120 is assigned is used for data. The storage capacity of the storage circuit 230 used for storage and to which the third storage area 130 is assigned Consider the case where a part of the voltage is used to hold data. The circuit 22[p1] (p1 is an integer between 1 and P) is a memory cell of the storage circuit 220. The write transistor included in the memory cell used as the second memory area 120 A voltage to be applied to the back gate of the capacitor is generated by a voltage generating circuit 22 [p2] (p2 is 1 or more, P is an integer that is equal to or less than p1 and is not p1. The back gate of the write transistor included in the memory cell used as region 130 It is assumed that the voltage to be applied to the

[0113] In this case, the storage unit 30 determines that the storage capacity of the second storage area 120 is insufficient. At this time, the storage unit 30 is in a state where all of the storage capacity of the storage circuit 220 is in use, and the storage circuit 23 The signal Sig1 is sent to the control unit 21 to inform the control unit 21 that there is free space in part of the storage capacity of 0.

[0114] By receiving the signal, the control unit 21 controls the voltage generating circuit 22[1] to the voltage generating circuit 23. The signal Sig2 is sent to the generating circuit 22[P], and the signal Sig3 is sent to the circuit 23B. The signals Sig2 and Sig3 are used to allocate the second storage area 120 to the storage circuit 230. It's a signal.

[0115] Specifically, the signal Sig2 allocates the second storage area 120 to a predetermined area of ​​the storage circuit 230. To assign the voltage, a voltage is applied to the back gate of the write transistor included in the region. It can be a signal for selecting a circuit for generating a voltage. The voltage generating circuit 22 [p3] (p3 is an integer between 1 and P, and is not p2) ) is selected. The voltage generating circuit 22[p3] is connected to the voltage generating circuit 22[p1]. They may be the same or different circuits.

[0116] In addition, for the voltage generating circuits that are not selected by the signal Sig2, For example, a voltage generating circuit and a wiring for supplying a driving voltage may be configured to stop the driving. By making the electrical connection between This allows the voltage generating circuit to be stopped, so that only the necessary voltage generating circuits are driven. Therefore, the power consumption of the control circuit 20 can be reduced.

[0117] The signal Sig3 is also used to select the buffer of the write transistor in the specified area of ​​the memory circuit 230. The voltage generated by the voltage generating circuit 22 [p3] is applied to BGL2, which is electrically connected to the clock gate. The signal Sig3 may be a signal including a command to apply a voltage. The back gate of the write transistor included in the third memory area 130 of 30 is connected to the back gate of the write transistor. It may also include a command to subsequently apply the voltage generated by the voltage generating circuit 22[p2].

[0118] The signal Sig3 is sent to the circuit 23B, and the voltage generating circuit 22[p3] generates The voltage is written to the area of ​​the memory circuit 230 to which the second memory area 120 is newly allocated. This allows the memory circuit 230 to The second storage area 120 can be allocated to the area. 1. This is a continuation of the block diagram shown in FIG. 1. The signal Sig3 is sent to the circuit 23B. Therefore, all of the remaining free memory areas of the memory circuit 230 of the memory unit 30 are used as the second memory. An example of allocation to area 120 is shown.

[0119] <Temperature control> Next, the write transistors (transistors M1, A method for changing the potential applied to the back gate of the transistor M2 will be described.

[0120] The temperature detection circuit 25 can have the configuration shown in FIG. In order to explain the electrical connection configuration with the sensing circuit 25, FIG. 22[1], the voltage generating circuit 22[P], the circuit 23A, and the wiring BGL1 are also shown. , the circuit 23B, the wiring BGL2, and the storage unit 30 are omitted.

[0121] The temperature detection circuit 25 includes a temperature sensor 25a, an analog-to-digital conversion circuit 25b, and a voltage and a control circuit 25c.

[0122] The temperature sensor 25a senses the temperature around the semiconductor device 11 and outputs a signal in response to the temperature. The analog signal output is converted into an analog digital signal. The temperature sensor 25a is made of, for example, platinum or nickel. Use a resistance thermometer such as Kel or copper, a thermistor, a thermocouple, an IC temperature sensor, etc. can be done.

[0123] The analog-to-digital conversion circuit 25b has a function of converting an analog signal into a digital signal. The digital signal is sent to the voltage control circuit 25c.

[0124] The voltage control circuit 25c has a function of generating a correction voltage in response to the digital signal. For example, the voltage control circuit 25c stores a correspondence table that associates the digital signal with the correction voltage. and a circuit for generating a correction voltage, and The magnitude of the corresponding correction voltage is read out from the digital signal sent from the conversion circuit 25b. After reading the level of the correction voltage, the circuit that generates the correction voltage generates the corresponding correction voltage. The generated signal is sent to the circuit 23A and the circuit 23B via the control unit 21. 6, 7, and 8, the temperature detection circuit 25 is electrically connected to the control unit 21. The temperature detection circuit 25 may be electrically connected directly to the circuit 23A and the circuit 23B. .

[0125] Here, the circuit 23A (circuit 23B) has a plurality of capacitance elements CF, and the plurality of capacitance elements CF One of the two pairs of electrodes is electrically connected to the plurality of wirings BGL1 (the plurality of wirings BGL2). The correction voltage sent to the circuit 23A (circuit 23B) is connected to the capacitance element The voltage is applied to the other of the two pairs of electrodes of the CF.

[0126] Incidentally, the circuit 23A (circuit 23B) has an internal circuit 23IN. N receives a signal from the control unit 21 and controls a plurality of wirings BGL1( The voltage generation circuits 22[1] to 22[P] are connected to the respective wirings BGL2). It has the function of applying multiple types of voltages generated by

[0127] When the potential of the back gate is changed depending on the temperature of the environment, first, the internal circuit 23I A potential is applied to the plurality of wirings BGL1 (the plurality of wirings BGL2) by N, and then the A correction voltage is applied to the other of the two pairs of electrodes of the capacitance element. The capacitance of the multiple wirings BGL1 (multiple wirings BGL2) is The potential fluctuates depending on the correction voltage. By having such a structure, the characteristics of the write transistor of the memory unit 30 can be compensated for depending on the environmental temperature. It can be corrected.

[0128] Note that one embodiment of the present invention is not limited to the circuit configuration described in this embodiment and may be modified as appropriate. It is possible.

[0129] Note that this embodiment mode can be appropriately combined with other embodiment modes shown in this specification. do.

[0130] (Embodiment 2) In this embodiment, the DOSRAM, NOSRAM, etc. described in the above embodiment are configured. An example of the configuration of the memory cell array 40 and its peripheral circuits will be described. In this embodiment, the memory cell array 40 and its peripheral circuits are collectively referred to as a memory device 200.

[0131] <Storage device configuration example> An example of the configuration of a storage device is shown in Figure 9. The storage device 200 includes a peripheral circuit 50 and a memory. The peripheral circuit 50 includes a row decoder 53, a word line driver circuit 54, and a memory cell array 40. 1, a bit line driver circuit 52, an output circuit 54, and a control logic circuit 56 9 also shows the control circuit 20 described in the first embodiment.

[0132] The bit line driver circuit 52 includes a column decoder 52a, a precharge circuit 52b, a sensor The precharge circuit 52b has a scan amplifier 52c and a write circuit 52d. SL, wiring CAL, wiring BIL, etc. The circuit c has a function of amplifying the data signals read from the wiring BIL and the wiring RBL. The wiring SL, the wiring CAL, and the wiring RBL are the memory cells of the memory cell array 40. The amplified data signal is transmitted to the output circuit. 54, and is output to the outside of the storage device 200 as a digital data signal RDATA. do.

[0133] The storage device 200 is supplied with a low power supply voltage (VSS) from the outside as a power supply voltage, and a low power supply voltage (VSS) from the outside as a power supply voltage for the peripheral circuit 50. A high power supply voltage (VDD) for the memory cell array 40 and a high power supply voltage (VIL) for the memory cell array 40 are supplied. .

[0134] The memory device 200 also receives control signals (CE, WE, RE), an address signal ADDR, A data signal WDATA is input from the outside. An address signal ADDR is input to a row decoder 5. 3 and the column decoder 52a, and WDATA is input to the write circuit 52d. do.

[0135] The control logic circuit 56 processes external input signals (CE, WE, RE). The CE generates control signals for the row decoder 53 and the column decoder 52a. WE is the write enable signal, and RE is the read enable signal. The signals processed by the control logic circuit 56 are not limited to these. Instead, other control signals may be input as required.

[0136] It should be noted that the above-mentioned circuits and signals can be appropriately selected or omitted as required.

[0137] Not only the memory cell array 40 but also the peripheral circuit 50 can be configured with OS transistors. This is preferable because the peripheral circuit 50 and the memory cell array 40 can be manufactured in the same manufacturing process. This makes it possible to reduce the manufacturing cost of the storage device 200.

[0138] <Configuration example of memory cell array> The details of the memory cell array 40 when DOSRAM is used as the memory cell are shown in FIG. The memory cell array 40 is shown in FIG. 0. The memory cell array 40 has m (m is an integer of 1 or more) memory cells arranged in a row. The memory cell array 221 has n (n is an integer of 1 or more) memory cells 221 in a row, totaling m×n memory cells 221. The cells 221 are arranged in a matrix. In FIG. 10, the addresses of the memory cells 221 are also shown. The notation is [1,1], [m,1], [i,j], [1,n], [m,n] (i is , m is an integer between 1 and m, and j is an integer between 1 and n. In the configuration of the memory cell 221, the memory cell array The number of wirings WOL connecting the array 40 and the word line driver circuit 51 is m (see FIG. 10, only the wiring WOL[1], the wiring WOL[i], and the wiring WOL[m] are illustrated. ), the number of wirings BGL connecting the memory cell array 40 and the control circuit 20 is also m. (In FIG. 10, only the wiring BGL[1], wiring BGL[i], and wiring BGL[m] are shown. In addition, the wiring connecting the memory cell array 40 and the bit line driver circuit 52 The number of BILs is n (in FIG. 10, the wiring BIL[1], the wiring BIL[j], the wiring BI Only L[n] is shown.)

[0139] In addition, details of the memory cell array 40 when NOSRAM is used as the memory cell are as follows: 11. The memory cell array 40 has m (m is an integer of 1 or more) memory cells arranged in a row. Each row has n (n is an integer of 1 or more) memory cells 231, for a total of m×n memory cells 231, The memory cells 231 are arranged in a matrix. In FIG. 11, the addresses of the memory cells 231 are Also shown are [1,1], [m,1], [i,j], [1,n], and [m,n]. (i is an integer between 1 and m, and j is an integer between 1 and n.) In the configuration of memory cell 231, the memory The number of wirings WOL connecting the cell array 40 and the word line driver circuit 51 is m. (In FIG. 11, only the wiring WOL[1], wiring WOL[i], and wiring WOL[m] are shown.) ), the number of wirings BGL connecting the memory cell array 40 and the control circuit 20 is also m. (In FIG. 11, only the wiring BGL[1], wiring BGL[i], and wiring BGL[m] are shown.) The number of wires in the wiring CAL is also m (in Figure 11, the number of wires in the wiring C Only AL[1], wiring CAL[i], and wiring CAL[m] are shown. The destinations connected to the memory cell 231 via the memory cell array are omitted. The wiring RBL, the wiring WBL, and the wiring SL that connect the bit line driver circuit 40 and the bit line driver circuit 52 The number of each is n (in FIG. 11, the number of wires is RBL[1], RBL[j], and RBL[j]). RBL[n], wiring WBL[1], wiring WBL[j], wiring WBL[n], wiring SL[1 ], wiring SL[j], and wiring SL[n] are only shown.

[0140] In the memory cell array 40 shown in each of FIGS. 10 and 11, the wiring BGL[1 ] to BGL[m] are provided for each row. The area of ​​each layer of the memory cell array 40 is changed row by row. The back gate of the transistor M1 (transistor M2) of the memory cell 221 (memory cell 231) The arrangement of the wiring BGL electrically connected to the port is not limited to that shown in FIGS. 10 and 11. For example, , the transistors M1 (M2) of the plurality of memory cells 221 (memory cells 231) ) are provided with wiring BGL, and each memory cell 221 (memory cell 231) is stored The area of ​​each layer of the device may be changed. Divide the cell 221 (memory cell 231) into regions such as 2x2 or 2x3, and It is also possible to provide different wirings BGL to each of the layers, thereby changing the area of ​​each layer of the memory device.

[0141] In each of the memory cell arrays 40 shown in FIGS. 10 and 11, the memory cells 221 The memory cells 231 are arranged two-dimensionally. As shown in FIG. 12A, the memory cells may be arranged three-dimensionally. The wiring BIL provided in the array 40 is approximately perpendicular to the bit line driver circuit 52. In addition, in FIG. 12B, a plurality of memory cell arrays 40 and bit line drivers 12(A) and 12(B), the memory Although the example of the cell 221 is shown, the memory cell 231 can also be arranged three-dimensionally in the same way. In FIGS. 12A and 12B, the bit line driver circuit 52 is shown in the lower layer. Instead of the line driver circuit 52, the word line driver circuit 51, the row decoder 53, or A plurality of these may be selected and stacked to form a circuit.

[0142] As shown in FIGS. 10 and 11, the memory device 200 is configured to reduce the circuit area. This allows for a smaller file size and a larger storage capacity.

[0143] 12(A) and 12(B), a memory cell array 40 shown in FIG. 10 and 11. In other words, the storage device 200 may be configured with a DOSRAM and an N The memory circuit 220 and the memory circuit 230 are overlapped with each other. In addition, in FIG. 13, the overlapping configuration For clarity, the voltage between each memory cell array 40 and the bit line driver circuit 52 is 13, the bit line driver circuit 52 is shown in the lower layer. However, instead of the bit line driver circuit 52, a word line driver circuit 51 and a row decoder In particular, a voltage generating layer may be provided in the lower layer. By providing circuits such as a memory circuit 220 and a precharge circuit, In each operation of 230, the circuitry can be shared with each other.

[0144] Note that one embodiment of the present invention is not limited to the circuit configuration described in this embodiment and may be modified as appropriate. For example, in this embodiment, the memory cell array 40 includes the memory cell 221 , and the memory cell 231 are applied, but other memory cells may be applied. Good too.

[0145] Note that this embodiment mode can be appropriately combined with other embodiment modes shown in this specification. do.

[0146] (Embodiment 3) In this embodiment mode, an OS transistor applicable to the semiconductor device described in the above embodiment mode will be described. An example of the configuration of the data will be described below.

[0147] <Configuration example of semiconductor device> The semiconductor device shown in FIG. 14 includes a transistor 300, a transistor 500, and a capacitor element 15A is a cross-sectional view of the transistor 500 in the channel length direction. 15(B) is a cross-sectional view of the transistor 500 in the channel width direction, and FIG. 15( 4C) is a cross-sectional view of the transistor 300 in the channel width direction.

[0148] The transistor 500 is a transistor having a metal oxide in a channel formation region (OS transistor). Since the off-state current of the transistor 500 is small, it is In particular, by using it for the transistor M2 of the memory cell 231, the first data This means that the refresh operation is less frequent or Since no refresh operation is required, the power consumption of the semiconductor device can be reduced.

[0149] The transistor 500 is provided above the transistor 300, and the capacitance element 600 is provided above the transistor 300. The capacitor 600 is provided above the transistor 300 and the transistor 500. can be the capacitance element CB in the memory cell 231.

[0150] The transistor 300 is disposed on a substrate 311, and includes a conductor 316, an insulator 315, and a substrate a semiconductor region 313 formed of a part of the semiconductor region 311; The transistor 300 has a resistive region 314a and a low resistive region 314b. For example, it can be applied to the transistor M3 in the above embodiment.

[0151] As shown in FIG. 15C, the transistor 300 has an upper surface of the semiconductor region 313 and a channel. The side surfaces in the width direction of the panel are covered with the conductor 316 via the insulator 315. By making the transistor 300 a fin type, the effective channel width is increased. This can improve the on-state characteristics of the transistor 300. Since the contribution can be increased, the off-state characteristics of the transistor 300 can be improved. Cut.

[0152] The transistor 300 may be either a p-channel type or an n-channel type. .

[0153] The region where the channel of the semiconductor region 313 is formed, the region nearby, the source region, or the drain region In the low resistance region 314a and the low resistance region 314b, which are to be the drain region, silicon It is preferable that the material contains a semiconductor such as a silicon-based semiconductor, and it is preferable that the material contains single crystal silicon. are Ge (germanium), SiGe (silicon germanium), and GaAs (gallium arsenide). Alternatively, the insulating layer 12 may be formed of a material containing gallium aluminum arsenide (GaAlAs), GaAlAs (gallium aluminum arsenide), or the like. It uses silicon in which the effective mass is controlled by applying stress to the crystal lattice and changing the lattice spacing. Alternatively, the transistor 30 may be formed by using GaAs and GaAlAs. 0 stands for HEMT (High Electron Mobility Transistor) ) can also be used.

[0154] The low resistance region 314a and the low resistance region 314b are semiconductor regions applied to the semiconductor region 313. In addition to the material, elements that give n-type conductivity, such as arsenic or phosphorus, or p-type conductivity, such as boron, are added. It contains an element that provides electrical conductivity.

[0155] The conductor 316, which functions as a gate electrode, is made of arsenic, phosphorus, or the like, which provides n-type conductivity. Semiconductor materials such as silicon that contain elements or elements that give them p-type conductivity, such as boron Conductive materials such as aluminum, metal, alloy, or metal oxide materials can be used.

[0156] Since the work function is determined by the material of the conductor, it is necessary to select the material of the conductor. Specifically, the conductor is made of nitride silicon, and the threshold voltage of the transistor can be adjusted. It is preferable to use materials such as tantalum or tantalum nitride. To achieve this, metal materials such as tungsten and aluminum are used as layers for the conductor. It is preferable to use tungsten, in particular, in terms of heat resistance.

[0157] The transistor 300 shown in FIG. 14 is an example, and the structure is not limited to this. An appropriate transistor may be used depending on the structure and driving method. For example, the transistor 300 The structure of the transistor 500 may be the same as that of the transistor 500 including an oxide semiconductor (see FIG. (Not shown) The details of the transistor 500 will be described later.

[0158] Over the transistor 300 are insulators 320, 322, 324, and The bodies 326 are stacked one on top of the other.

[0159] The insulators 320, 322, 324, and 326 may be, for example, oxide. Silicon, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, oxide Aluminum oxynitride, aluminum nitride oxide, aluminum nitride, etc. may be used.

[0160] In this specification, silicon oxynitride refers to a material having a higher content of oxygen than nitrogen in its composition. Silicon nitride oxide refers to a material that contains more nitrogen than oxygen. In this specification, aluminum oxynitride refers to a material with a high content. Aluminum oxide nitride is a material that has a higher oxygen content than nitrogen. It refers to a material that contains more nitrogen than oxygen as a constituent.

[0161] The insulator 322 serves to eliminate a step caused by the transistor 300 and other components disposed below it. For example, the upper surface of the insulator 322 may have a function as a planarizing film to reduce the To improve flatness, the surface is flattened by a planarization process using chemical mechanical polishing (CMP) or other methods. It may be done.

[0162] The insulator 324 is also provided with a substrate 311 or a transistor 300, etc. A film having a barrier property that prevents hydrogen and impurities from diffusing is used in the area where the capacitor 500 is provided. It is preferable that

[0163] An example of a film having a barrier property against hydrogen is silicon nitride formed by CVD. Here, a semiconductor having an oxide semiconductor such as the transistor 500 can be used. The diffusion of hydrogen into semiconductor elements can cause a deterioration in the characteristics of the semiconductor elements. Therefore, a film that suppresses hydrogen diffusion is provided between the transistor 500 and the transistor 300. Specifically, the film that suppresses the diffusion of hydrogen is a film that reduces the amount of hydrogen desorption. The membrane is thin.

[0164] The amount of hydrogen desorption can be analyzed using, for example, thermal desorption spectroscopy (TDS). For example, the amount of hydrogen desorbed from the insulator 324 can be determined by TDS analysis as follows: In the range of 50°C to 500°C, the amount of desorption converted to hydrogen atoms is Converted to a hit, it's 10 x 10 15 atoms / cm 2 Less than or equal to 5 x 10 15 a toms / cm 2 The following is fine.

[0165] It is preferable that the insulator 326 has a lower relative dielectric constant than the insulator 324. For example, The dielectric constant of the insulator 326 is preferably less than 4, more preferably less than 3. The relative dielectric constant of the body 326 is preferably 0.7 times or less, and more preferably 0.6 times or less, of the relative dielectric constant of the insulator 324. By using a material with a low dielectric constant as the interlayer film, the parasitic capacitance generated between the wirings can be reduced. can be reduced.

[0166] The insulators 320, 322, 324, and 326 are connected to the capacitance element 6. 00, or the conductor 328 and the conductor 330 connected to the transistor 500 are embedded. The conductors 328 and 330 function as plugs or wiring. In addition, the conductors that function as plugs or wiring are grouped together to form the same structure. In addition, in this specification and the like, a wiring and a plug connected to the wiring may be In other words, when a part of the conductor functions as a wiring, In some cases, a portion of the conductor functions as a plug.

[0167] The materials for each plug and wiring (conductor 328, conductor 330, etc.) include metal materials, alloys, and the like. Conductive materials such as gold, metal nitride, or metal oxide materials are used in a single layer or laminated layers. High-melting-point materials such as tungsten and molybdenum, which are both heat-resistant and conductive, can be used. It is preferable to use a metal such as tungsten, and it is particularly preferable to use aluminum. It is preferable to form the wiring board from a low-resistance conductive material such as aluminum or copper. This allows the wiring resistance to be reduced.

[0168] A wiring layer may be provided on the insulator 326 and the conductor 330. For example, in FIG. An insulator 350, an insulator 352, and an insulator 354 are stacked in this order. In addition, a conductor 356 is formed on the insulators 350, 352, and 354. The conductor 356 functions as a plug or wiring that connects to the transistor 300. The conductor 356 is made of the same material as the conductors 328 and 330. It is possible.

[0169] For example, the insulator 350 has a barrier property against hydrogen, similar to the insulator 324. It is preferable to use an insulator having a barrier property against hydrogen. It is preferable that the insulating material 350 has a barrier property against hydrogen. A conductor having a barrier property against hydrogen is formed in the opening. The transistor 300 and the transistor 500 can be separated by a barrier layer. The diffusion of hydrogen from the transistor 300 to the transistor 500 can be suppressed.

[0170] As a conductor having a barrier property against hydrogen, for example, tantalum nitride or the like is used. In addition, by laminating tantalum nitride and highly conductive tungsten, The diffusion of hydrogen from the transistor 300 can be suppressed while maintaining the overall conductivity. In this case, the tantalum nitride layer having a barrier property against hydrogen is It is preferable that the insulating body 350 has a structure in which the insulating body 350 is in contact with the insulating body 350.

[0171] A wiring layer may be provided on the insulator 354 and the conductor 356. For example, in FIG. An insulator 360, an insulator 362, and an insulator 364 are stacked in this order. In addition, a conductor 366 is formed on the insulators 360, 362, and 364. The conductor 366 functions as a plug or wiring. The conductive body 328 and the conductive body 330 may be formed using the same materials.

[0172] For example, the insulator 360 has a barrier property against hydrogen, similar to the insulator 324. It is preferable to use an insulator having a barrier property against hydrogen. It is preferable that the insulating material 360 has a barrier property against hydrogen. It is preferable that a conductor having a barrier property against hydrogen is formed in the opening. By construction, transistor 300 and transistor 500 are separated by a barrier layer. This makes it possible to suppress the diffusion of hydrogen from the transistor 300 to the transistor 500. can.

[0173] A wiring layer may be provided on the insulator 364 and the conductor 366. For example, in FIG. An insulator 370, an insulator 372, and an insulator 374 are stacked in this order. In addition, a conductor 376 is formed on the insulators 370, 372, and 374. The conductor 376 functions as a plug or wiring. The conductive body 328 and the conductive body 330 may be formed using the same materials.

[0174] For example, the insulator 370 has a barrier property against hydrogen, similar to the insulator 324. It is preferable to use an insulator having a barrier property against hydrogen. In particular, an insulator 370 having a barrier property against hydrogen is useful. It is preferable that a conductor having a barrier property against hydrogen is formed in the opening. By construction, transistor 300 and transistor 500 are separated by a barrier layer. This makes it possible to suppress the diffusion of hydrogen from the transistor 300 to the transistor 500. can.

[0175] A wiring layer may be provided on the insulator 374 and the conductor 376. For example, in FIG. An insulator 380, an insulator 382, ​​and an insulator 384 are stacked in this order. In addition, a conductor 386 is formed on the insulators 380, 382, ​​and 384. The conductor 386 functions as a plug or wiring. The conductive body 328 and the conductive body 330 may be formed using the same materials.

[0176] For example, the insulator 380 has a barrier property against hydrogen, similar to the insulator 324. It is preferable to use an insulator having a barrier property against hydrogen. It is preferable that the insulator 380 has a barrier property against hydrogen. It is preferable that a conductor having a barrier property against hydrogen is formed in the opening. By construction, transistor 300 and transistor 500 are separated by a barrier layer. This makes it possible to suppress the diffusion of hydrogen from the transistor 300 to the transistor 500. can.

[0177] In the above, the wiring layer including the conductor 356, the wiring layer including the conductor 366, the conductor 376 The wiring layer including the conductor 386 has been described above. The semiconductor device is not limited to this. Alternatively, the number of wiring layers may be three or less, or five or more wiring layers similar to the wiring layer including the conductor 356 may be provided. Good too.

[0178] On the insulator 384, an insulator 510, an insulator 512, an insulator 514, and an insulator 516 are formed. , are stacked in this order. It is preferable that any of the bodies 516 is made of a material that has a barrier property against oxygen and hydrogen. .

[0179] For example, the insulator 510 and the insulator 514 may include, for example, the substrate 311 or the transistor. Hydrogen and impurities diffuse from the region where the capacitor 300 is provided to the region where the transistor 500 is provided. It is preferable to use a film having a barrier property that prevents the diffusion of the insulator 324. The same materials as those mentioned above can be used.

[0180] As an example of a film with barrier properties against hydrogen, silicon nitride formed by CVD is used. Here, a semiconductor element including an oxide semiconductor, such as the transistor 500, However, the diffusion of hydrogen may deteriorate the characteristics of the semiconductor element. A film that suppresses hydrogen diffusion is used between the transistor 500 and the transistor 300. Specifically, the film that suppresses hydrogen diffusion is a film that releases a small amount of hydrogen. do.

[0181] In addition, as a film having a barrier property against hydrogen, for example, an insulator 510 and an insulator 5 14 uses metal oxides such as aluminum oxide, hafnium oxide, and tantalum oxide. It is preferable.

[0182] In particular, aluminum oxide is a material that can absorb oxygen and hydrogen, which can cause fluctuations in the electrical characteristics of transistors. Therefore, it has a high blocking effect that prevents impurities such as acid and moisture from passing through the membrane. Aluminum oxide is a material that can absorb impurities such as hydrogen and moisture during and after the transistor manufacturing process. This can prevent impurities from being mixed into the transistor 500. Therefore, the release of oxygen from the oxide constituting the transistor 5 can be suppressed. Suitable for use as a protective film against 00.

[0183] For example, the insulators 512 and 516 may be made of the same material as the insulator 320. In addition, materials with a relatively low dielectric constant can be used for these insulators. For example, the insulator 512 and the insulating The body 516 may be a silicon oxide film, a silicon oxynitride film, or the like.

[0184] In addition, the insulators 510, 512, 514, and 516 are provided with conductors 5 18, and conductors (for example, conductor 503) that constitute the transistor 500 are embedded. Note that the conductor 518 is connected to the capacitor 600 or the transistor 300. The conductor 518 functions as a plug or a wiring. It can be provided using the same material as 30.

[0185] In particular, the insulator 510 and the conductor 518 in the area in contact with the insulator 514 are free of oxygen, hydrogen, It is preferable that the conductive material has a barrier property against water. The transistor 300 and the transistor 500 have barrier properties against oxygen, hydrogen, and water. The layer can be separated, and hydrogen diffusion from transistor 300 to transistor 500 can be suppressed.

[0186] Above the insulator 516 is the transistor 500 .

[0187] As shown in FIGS. 15A and 15B, the transistor 500 includes an insulator 514 and an insulator The conductor 503 is disposed so as to be embedded in the insulator 516, and the insulator 516 and the conductor 503 are disposed so as to be embedded in the insulator 516. an insulator 520 disposed on the insulator 520; an insulator 522 disposed on the insulator 520; An insulator 524 is disposed on the body 522, and an oxide 530 is disposed on the insulator 524. a, oxide 530b disposed on oxide 530a, and oxide 530b disposed on oxide 530b. Conductor 542a and conductor 542b are arranged in parallel, and conductor 542a and conductor 542b are arranged in parallel. b, and an opening is formed between the conductor 542a and the conductor 542b. The oxide 530c is formed on the bottom and sides of the opening. an insulator 550 disposed on the surface; and a conductor 560 disposed on the surface of the insulator 550. Has.

[0188] As shown in FIGS. 15(A) and 15(B), the oxide 530a, the oxide 530b, the conductor 542a, and an insulator 544 is disposed between the conductor 542b and the insulator 580. 15(A) and 15(B), the conductor 560 is preferably an insulator 550. and a conductor 560a provided inside the conductor 560a so as to be embedded inside the conductor 560a. It is preferable that the conductive material 560b is provided with a conductive material 560b. As shown, the insulator 574 is disposed on the insulator 580, the conductor 560, and the insulator 550. It is preferable that

[0189] In the following, the oxide 530a, the oxide 530b, and the oxide 530c will be collectively referred to as oxides 530a, 530b, and 530c. It is sometimes called oxide 530.

[0190] In the transistor 500, an oxide is formed in the region where the channel is formed and in the vicinity thereof. 5 shows a structure in which three layers of oxide 530a, oxide 530b, and oxide 530c are stacked. However, the present invention is not limited to this. For example, a single layer of oxide 530b, an oxide a two-layer structure of oxide 530b and oxide 530a; a two-layer structure of oxide 530b and oxide 530c; Alternatively, a stacked structure of four or more layers may be provided. Although the conductive body 560 is shown as a two-layer laminated structure, the present invention is not limited to this. For example, the conductor 560 may have a single layer structure or a laminated structure of three or more layers. The transistor 500 shown in FIGS. 14 and 15(A) and (B) is an example. There is no limitation to the structure, and appropriate transistors may be used depending on the circuit configuration and driving method.

[0191] Here, the conductor 560 functions as the gate electrode of the transistor, and the conductors 542a and The conductor 542b functions as a source electrode and a drain electrode, respectively. The conductor 560 is sandwiched between the opening of the insulator 580 and the conductors 542a and 542b. The conductor 560, the conductor 542a, and the conductor 542b are formed so as to be embedded in the region. The placement of 42b is selected to be self-aligned with the opening of the insulator 580. In the transistor 500, the gate electrode is self-aligned between the source electrode and the drain electrode. Therefore, the conductor 560 can be positioned with a margin for alignment. Since the transistor 500 can be formed without any additional wiring, the area occupied by the transistor 500 can be reduced. This allows for miniaturization and high integration of semiconductor devices.

[0192] Furthermore, the conductor 560 is self-aligned in the region between the conductors 542a and 542b. Since the conductor 560 is formed, the conductor 560 has an overlapping region with the conductor 542a or the conductor 542b. As a result, the gap formed between the conductor 560 and the conductors 542a and 542b is Therefore, the switching speed of the transistor 500 can be improved. This improves the sound quality and provides high frequency characteristics.

[0193] Conductor 560 may function as a first gate (also called a top gate) electrode. The conductor 503 also functions as a second gate (also called a bottom gate) electrode. In this case, the potential applied to the conductor 503 may be different from the potential applied to the conductor 560. The threshold voltage of the transistor 500 is controlled by changing them independently without linking them together. In particular, applying a negative potential to the conductor 503 can turn on the transistor 5 It is possible to increase the threshold voltage of 00 to be higher than 0V and reduce the off-current. Therefore, when a negative potential is applied to the conductor 503, the conductor 560 This can reduce the drain current when the potential applied to is 0V.

[0194] The conductor 503 is arranged to overlap the oxide 530 and the conductor 560. Therefore, when a potential is applied to the conductor 560 and the conductor 503, The electric field and the electric field generated by the conductor 503 are connected, and a channel is formed in the oxide 530. In this specification and the like, the first gate electrode and the second gate electrode can cover the region where the first gate electrode and the second gate electrode are formed. The structure of a transistor in which the electric field of the gate electrode electrically surrounds the channel formation region is called This is called a surrounded channel (S-channel) structure.

[0195] The conductor 503 has the same structure as the conductor 518, and the insulators 514 and 5 Conductor 503a is formed in contact with the inner wall of opening 16, and conductor 503b is formed further inside. It has been completed.

[0196] The insulators 520, 522, 524, and 550 serve as gate insulating films. It has all the functions.

[0197] Here, the insulator 524 in contact with the oxide 530 has more oxygen than the stoichiometric composition. It is preferable to use an insulator that contains a large amount of oxygen. That is, the insulator 524 has an excess oxygen region. It is preferable that the insulator containing such excess oxygen is formed in the oxide 530. By providing the oxide 530 in contact with the oxide 530, oxygen vacancies in the oxide 530 are reduced, and the signal quality of the transistor 500 is improved. Reliability can be improved.

[0198] As an insulator having an excess oxygen region, specifically, an oxide in which a part of oxygen is released by heating is used. It is preferable to use oxide materials. Oxides that release oxygen when heated are called TDS (Th Thermal Desorption Spectroscopy (DSS) analysis revealed that the oxygen atoms The converted amount of oxygen desorption is 1.0 x 10 18 atoms / cm 3 Above 1.0, preferably 1.0 x10 19 atoms / cm 3 More preferably, 2.0 × 10 19 atoms / c m 3 or more, or 3.0 x 10 20 atoms / cm 3 The oxide film is as described above. The surface temperature of the film during the TDS analysis is 100°C or higher and 700°C or lower. The temperature range is preferably from 0°C to 400°C.

[0199] Also, if the insulator 524 has an excess oxygen region, the insulator 522 may be oxygen-rich (e.g., It has the function of suppressing the diffusion of oxygen atoms, oxygen molecules, etc. (the oxygen is less likely to permeate) It is preferable that:

[0200] The insulator 522 has a function of suppressing the diffusion of oxygen and impurities, and the oxide 530 The oxygen contained in the conductor 503 is preferably not diffused to the insulator 520 side. This can prevent the insulator 524 and the oxide 530 from reacting with oxygen.

[0201] The insulator 522 may be, for example, aluminum oxide, hafnium oxide, aluminum and hafnium oxide. oxides containing ammonium (hafnium aluminate), tantalum oxide, zirconium oxide, titanium Lead zirconate titanate (PZT), strontium titanate (SrTiO3), or (Ba Insulators containing so-called high-k materials such as (Sr, Sr)TiO3 (BST) are used as single layers or laminated layers. As transistors become smaller and more highly integrated, the gate insulating layer Thinning the film can cause problems such as leakage current. Functions as a gate insulating film By using a high-k material as the insulator, the transistor behavior can be improved while maintaining the physical thickness. This makes it possible to reduce the gate potential during operation.

[0202] In particular, it has the function of suppressing the diffusion of impurities and oxygen (the oxygen is difficult to penetrate) ) Use an insulator containing oxide of one or both of aluminum and hafnium, which are insulating materials. It is recommended to use an oxide of aluminum or hafnium as an insulator. Aluminum oxide, hafnium oxide, oxides containing aluminum and hafnium (hafnium It is preferable to use a material such as aluminum aluminate. When formed, the insulator 522 prevents oxygen from being released from the oxide 530 and prevents the transistor 500 from being damaged. The layer functions as a layer that suppresses the intrusion of impurities such as hydrogen from the surrounding area into the oxide 530.

[0203] Alternatively, for example, aluminum oxide, bismuth oxide, or germanium oxide may be added to these insulators. Niobium oxide, silicon oxide, titanium oxide, tungsten oxide, yttrium oxide, Alternatively, zirconium oxide may be added to these insulators. Alternatively, these insulators may be nitrided. Silicon oxide, silicon oxynitride, or silicon nitride may be laminated on the edge.

[0204] The insulator 520 is preferably thermally stable. For example, silicon oxide and Silicon oxide nitride and silicon oxynitride are suitable because they are thermally stable. By combining the insulator with silicon oxide or silicon oxynitride, thermally stable and It is possible to obtain an insulator 520 having a laminated structure with a high relative dielectric constant.

[0205] The insulators 520, 522, and 524 each have a laminated structure of two or more layers. In this case, the laminated structure is not limited to the same material, and may be made of different materials. A laminated structure may also be used.

[0206] The transistor 500 includes an oxide 530 including a channel formation region, and an oxide semiconductor It is preferable to use a functional metal oxide. For example, the oxide 530 is In-M- Zn oxide (element M is aluminum, gallium, yttrium, copper, vanadium, beryl Sodium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, la tantalum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium It is preferable to use a metal oxide such as one or more selected from the following. Examples of the In-M-Zn oxide that can be used as the In-Zn oxide include CAAC-OS, The oxide 530 is preferably an In—Ga oxide, an I n-Zn oxide may also be used.

[0207] The metal oxide that functions as the channel forming region in the oxide 530 has a band gap It is preferable to use one having a value of 2 eV or more, preferably 2.5 eV or more. The use of metal oxides with wide band gaps reduces the off-state current of transistors. It is possible.

[0208] The oxide 530 has an oxide 530a under the oxide 530b, so that the oxide 530a The diffusion of impurities from structures formed below the oxide 530b can be suppressed. In addition, by having the oxide 530c on the oxide 530b, the oxide 530c can be formed. Therefore, the diffusion of impurities from the structure formed above into the oxide 530b can be suppressed. do.

[0209] The oxide 530 has a layered structure made of oxides with different atomic ratios of metal atoms. Specifically, in the metal oxide used for the oxide 530a, the constituent elements are preferably The atomic ratio of element M in the oxide 530b is It is preferable that the atomic ratio of the metal oxide used for the oxide 530a is larger than that of the element M. In the oxide 530b, the atomic ratio of the element M to In is It is preferable that the atomic ratio of element M to In is larger than that of element M. In the metal oxide used, the atomic ratio of In to the element M is It is preferable that the atomic ratio of In to the element M in the metal oxide is larger than that of In. The oxide 530c is a metal oxide that can be used for the oxide 530a or the oxide 530b. can be used.

[0210] The energy of the conduction band minimum of the oxide 530a and the oxide 530c is It is preferable that the energy of the oxide is higher than the energy of the bottom of the conduction band of oxide b. The electron affinity of oxide 530a and oxide 530c is smaller than that of oxide 530b. It is preferable that:

[0211] Here, at the junctions of the oxide 530a, the oxide 530b, and the oxide 530c, The energy level of the lower conduction band edge changes gradually. The energy levels of the conduction band minimum at the junction of 530b and oxide 530c are continuous. In order to achieve this, the oxide 530 The interface between oxide 530a and oxide 530b, and the interface between oxide 530b and oxide 530c are It is preferable to lower the defect level density of the resulting mixed layer.

[0212] Specifically, oxide 530a and oxide 530b, and oxide 530b and oxide 530c are By having a common element other than oxygen (as the main component), a mixed layer with low defect level density is formed. For example, when the oxide 530b is an In-Ga-Zn oxide, the oxide 530a and oxide 530c are In-Ga-Zn oxide, Ga-Zn oxide, oxide Gallium or the like may be used.

[0213] At this time, the main path of the carriers is the oxide 530b. By configuring the oxide 530c as described above, the interface between the oxide 530a and the oxide 530b and the oxide The defect state density at the interface between the substrate 530b and the oxide 530c can be reduced. Therefore, the influence of interface scattering on carrier conduction is reduced, and the transistor 500 has a high On-current can be obtained.

[0214] On the oxide 530b, a conductor 542a is formed, which functions as a source electrode and a drain electrode. The conductors 542a and 542b are provided. Aluminum, chromium, copper, silver, gold, platinum, tantalum, nickel, titanium, molybdenum, ungsten, hafnium, vanadium, niobium, manganese, magnesium, zirconium , beryllium, indium, ruthenium, iridium, strontium, and lanthanum The metal elements mentioned above, or alloys containing the above metal elements, or combinations of the above metal elements It is preferable to use alloys such as tantalum nitride, titanium nitride, tungsten nitride, etc. Nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, oxides Ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, lanthanum and It is preferable to use an oxide containing nickel. In addition, tantalum nitride, titanium nitride, Nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide Ruthenium, ruthenium nitride, oxides containing strontium and ruthenium, lanthanum and nickel Oxides containing these are conductive materials that are resistant to oxidation, or materials that maintain conductivity even after absorbing oxygen. This is preferable because it is a

[0215] As shown in FIG. 15(A), the oxide 530 is formed of the conductor 542a (conductor 542b ) and its vicinity, a region 543a and a region 543b are formed as low resistance regions. In this case, the region 543a may be used as either a source region or a drain region. The region 543b functions as the other of the source region and the drain region. A channel forming region is formed in the region sandwiched between region 543a and region 543b.

[0216] By providing the conductor 542a (conductor 542b) so as to be in contact with the oxide 530, The oxygen concentration in the region 543a (region 543b) may decrease. The metal contained in the conductor 542a (conductor 542b) and the oxide 530 are In such a case, a metal compound layer containing the component may be formed in the region 543a (region The carrier concentration in the region 543a (region 543b) increases, and the region 543a (region 543b) becomes a low resistance region. become.

[0217] The insulator 544 is provided to cover the conductor 542a and the conductor 542b. The insulator 544 prevents oxidation of the oxide 542a and the conductor 542b. 30 and may be provided so as to be in contact with the insulator 524.

[0218] Insulator 544 includes hafnium, aluminum, gallium, yttrium, and zirconium. tungsten, titanium, tantalum, nickel, germanium, or magnesium A metal oxide containing one or more selected from the above can be used.

[0219] In particular, the insulator 544 may be an oxide of aluminum or hafnium, or both. Aluminum oxide, hafnium oxide, aluminum and hafnium are insulators containing It is preferable to use oxides containing hafnium (hafnium aluminate). Aluminate has higher heat resistance than hafnium oxide film. In this case, the conductor 542a and the conductor 542b are preferably resistant to crystallization. is a material that is oxidation-resistant or whose conductivity does not decrease significantly even when it absorbs oxygen. The insulator 544 is not an essential component. It can be appropriately designed depending on the desired transistor characteristics. That's fine.

[0220] The insulator 550 functions as a gate insulating film. It is preferable that the insulator 550 is disposed in contact with the upper and side surfaces of the insulator 550. Similar to 524, it is made using an insulator that contains excess oxygen and releases oxygen when heated. It is preferable to form

[0221] Specifically, silicon oxide having excess oxygen, silicon oxynitride, silicon nitride oxide, Silicon nitride, fluorine-doped silicon oxide, carbon-doped silicon oxide, carbon and Nitrogen-doped silicon oxide and vacant silicon oxide can be used. Silicon oxide and silicon oxynitride are preferred because they are stable to heat.

[0222] An insulator that releases oxygen when heated is used as the insulator 550, and is placed on the top surface of the oxide 530c. By providing the oxide 530b in contact with the insulator 550, the oxide 530c passes through the oxide 530b. In addition, oxygen can be effectively supplied to the channel formation region of the insulator 524. In addition, it is preferable that the concentration of impurities such as water or hydrogen in the insulator 550 is reduced. The thickness of the insulator 550 is preferably 1 nm or more and 20 nm or less.

[0223] In addition, in order to efficiently supply excess oxygen contained in the insulator 550 to the oxide 530, A metal oxide may be provided between the insulating material 550 and the conductor 560. It is preferable to suppress the diffusion of oxygen from the body 550 to the conductor 560. By providing a metal oxide, the diffusion of excess oxygen from the insulator 550 to the conductor 560 is suppressed. In other words, it is possible to suppress the decrease in the amount of excess oxygen supplied to the oxide 530. In addition, oxidation of the conductor 560 due to excess oxygen can be suppressed. Any material that can be used for the insulator 544 may be used.

[0224] The conductor 560 functioning as the first gate electrode has a two-layer structure in FIGS. However, it may have a single layer structure or a laminated structure of three or more layers.

[0225] The conductor 560a is a hydrogen atom, a hydrogen molecule, a water molecule, a nitrogen atom, a nitrogen molecule, or a nitrogen oxide molecule. (N2O, NO, NO2, etc.), conductive material with the function of suppressing the diffusion of impurities such as copper atoms It is preferable to use a material containing oxygen (for example, oxygen atoms, oxygen molecules, etc.). It is preferable to use a conductive material that has the function of suppressing the diffusion of the conductor 56. Oa has the function of suppressing oxygen diffusion, so the oxygen contained in the insulator 550 This can prevent the conductor 560b from being oxidized and the conductivity from decreasing. Examples of conductive materials that have the function of suppressing this include tantalum, tantalum nitride, and ruthenium. It is preferable to use ruthenium, ruthenium oxide, or the like.

[0226] The conductor 560b is a conductive material mainly composed of tungsten, copper, or aluminum. In addition, since the conductor 560b also functions as a wiring, It is preferable to use a conductor with high electrical conductivity. The conductor 560b may have a layered structure. For example, a laminated structure of titanium, titanium nitride and the above conductive material may be used.

[0227] The insulator 580 is provided on the conductor 542a and the conductor 542b via the insulator 544. Preferably, the insulator 580 has an excess oxygen region. For example, the insulator 58 0, silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, fluorine silicon oxide doped with carbon, silicon oxide doped with carbon and nitrogen It is preferable that the material contains silicon, silicon oxide having pores, or resin. Silicon nitride and silicon oxynitride are preferred because they are thermally stable. However, silicon oxide with vacancies can easily form excess oxygen regions in later processes. This is preferable because it can

[0228] The insulator 580 has an excess oxygen region and releases oxygen when heated. By providing the insulator 580 in contact with the oxide 530c, the oxygen in the insulator 580 is transferred to the oxide 530c through the oxide 530c. 30a and oxide 530b. Alternatively, it is preferable that the concentration of impurities such as hydrogen is reduced.

[0229] The opening in the insulator 580 is formed to overlap the region between the conductor 542a and the conductor 542b. As a result, the conductor 560 is inserted through the opening in the insulator 580 and the conductor 542a and the conductor 542b. It is formed so as to be embedded in the region sandwiched between 542b.

[0230] In miniaturizing semiconductor devices, it is required to shorten the gate length. It is necessary to prevent the conductivity of the conductor 60 from decreasing. In this embodiment, the conductive material 560 has a high aspect ratio. The conductor 560 is provided so as to be embedded in the opening of the insulator 580. Even a shape with a high ratio can be formed without causing the conductor 560 to collapse during the process. Cut.

[0231] The insulator 574 is connected to the upper surface of the insulator 580, the upper surface of the conductor 560, and the upper surface of the insulator 550. The insulator 574 is preferably provided in contact with the , insulator 550, and insulator 580. This allows for the provision of excess oxygen regions. Oxygen can be supplied into the oxide 530 from the excess oxygen region.

[0232] For example, the insulator 574 may be hafnium, aluminum, gallium, yttrium, Zirconium, tungsten, titanium, tantalum, nickel, germanium, or magnesium Metal oxides containing one or more metals selected from the group consisting of sodium, .

[0233] In particular, aluminum oxide has a high barrier property and is a thin film of 0.5 nm to 3.0 nm. Therefore, the diffusion of hydrogen and nitrogen can be suppressed even if the sputtering method is used. The aluminum oxide film formed by this method is both an oxygen source and a barrier to impurities such as hydrogen. It can also function as a membrane.

[0234] In addition, it is preferable to provide an insulator 581 that functions as an interlayer film over the insulator 574. The insulator 581, like the insulator 524, has a low impurity concentration such as water or hydrogen. It is preferably reduced.

[0235] In addition, the openings formed in the insulators 581, 574, 580, and 544 Conductor 540a and conductor 540b are placed in the opening. The conductors 540a and 540b are provided facing each other with the conductor 560 in between. It has the same structure as the conductor 546 and the conductor 548 described later.

[0236] An insulator 582 is provided on the insulator 581. The insulator 582 is resistant to oxygen and hydrogen. Therefore, the insulator 582 is preferably made of an insulating material. The insulator 582 may be made of the same material as the insulator 514. For example, aluminum oxide may be used. It is preferable to use metal oxides such as tungsten oxide, hafnium oxide, and tantalum oxide.

[0237] In particular, aluminum oxide is a material that can absorb oxygen and hydrogen, which can cause fluctuations in the electrical characteristics of transistors. Therefore, it has a high blocking effect that prevents impurities such as acid and moisture from passing through the membrane. Aluminum oxide is a material that can absorb impurities such as hydrogen and moisture during and after the transistor manufacturing process. This can prevent impurities from being mixed into the transistor 500. Therefore, the release of oxygen from the oxide constituting the transistor 5 can be suppressed. Suitable for use as a protective film against 00.

[0238] An insulator 586 is provided on the insulator 582. The insulator 586 is 320. In addition, these insulators have a relatively low dielectric constant. By using low-cost materials, the parasitic capacitance between wirings can be reduced. For example, As the insulator 586, a silicon oxide film, a silicon oxynitride film, or the like can be used.

[0239] Also, the insulator 520, the insulator 522, the insulator 524, the insulator 544, the insulator 580, the insulator The edge 574, the insulator 581, the insulator 582, and the insulator 586 are provided with the conductor 546 and Conductors 548 and the like are embedded.

[0240] The conductor 546 and the conductor 548 are connected to the capacitor 600, the transistor 500, or the transistor The conductor 546 functions as a plug or wiring that connects to the transistor 300. The conductor 548 can be formed using the same material as the conductor 328 and the conductor 330. Cut.

[0241] Next, a capacitor 600 is provided above the transistor 500. 600 includes a conductor 610, a conductor 620, and an insulator 630.

[0242] Moreover, a conductor 612 may be provided over the conductor 546 and the conductor 548. The conductor 12 functions as a plug or wiring that connects to the transistor 500. The conductor 610 functions as an electrode of the capacitor 600. The body 610 can be formed simultaneously.

[0243] The conductor 612 and the conductor 610 may be made of molybdenum, titanium, tantalum, or tungsten. a metal film containing an element selected from aluminum, copper, chromium, neodymium, and scandium; Or a metal nitride film containing the above elements (tantalum nitride film, titanium nitride film, molybdenum nitride film) Indium tin oxide, tungsten nitride film, etc. can be used. Indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide Indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium Conductive materials such as indium zinc oxide and indium tin oxide doped with silicon oxide are used. It is also possible.

[0244] In FIG. 14, the conductor 612 and the conductor 610 are shown as single-layer structures, but the present invention is not limited to this structure. For example, a conductive material having a barrier property and a conductive material having a high conductivity may be used. Conductors with barrier properties and high adhesion to highly conductive conductors A thin conductor may be formed.

[0245] The conductor 620 is provided so as to overlap with the conductor 610 with the insulator 630 interposed therebetween. The conductor 620 is made of a conductive material such as a metal material, an alloy material, or a metal oxide material. High-melting-point materials such as tungsten and molybdenum, which have both heat resistance and electrical conductivity, are used. It is preferable to use tungsten, and it is particularly preferable to use tungsten. When forming the structure at the same time as other structures, low-resistance metal materials such as Cu (copper) and Al (aluminum) are used. It is best to use a

[0246] An insulator 650 is provided on the conductor 620 and the insulator 630. The insulator 650 can be formed using the same material as the insulator 320. It may also function as a planarizing film that covers the underlying unevenness.

[0247] By using this structure, a semiconductor device using a transistor having an oxide semiconductor This can suppress the fluctuation of electrical characteristics and improve reliability. In semiconductor devices using transistors having compound semiconductors, miniaturization or high integration is being attempted. It is possible.

[0248] <Example of transistor structure> Note that the transistor 500 of the semiconductor device described in this embodiment is not limited to the above structure. The following describes examples of structures that can be used for the transistor 500. The transistors described below are modifications of the transistors described above. Therefore, in the following description, differences will be mainly explained, and the same points may be omitted.

[0249] <<Transistor structure example 1>> An example of the structure of the transistor 500A will be described with reference to FIGS. FIG. 16A is a top view of a transistor 500A. FIG. 16B is a top view of the transistor 500A shown in FIG. 16(C) is a cross-sectional view of the area indicated by the dashed line L1-L2 in FIG. 16(A) is a cross-sectional view of the portion indicated by the line W1-W2. For this reason, some elements are omitted from the illustration.

[0250] 16A, 16B, and 16C, a transistor 500A and a layer functioning as an interlayer film are shown. Insulators 511, 512, 514, 516, 580, and 5 16(A), (B) and (C) show the insulator 581. Conductor 540a, conductor 540b, and The conductor 505 is shown. In particular, the conductor 540a and the conductor 540b are contact plugs. The conductor 505 functions as a wiring.

[0251] The transistor 500A has a conductor 560 (conductor 56 0a and conductor 560b), and conductor 503 (conductor 503a and conductor 503b), and an insulator 550 that functions as a first gate insulating film. , an insulator 520, an insulator 522, and an insulator 524 which function as a second gate insulating film; , an oxide 530 (oxide 530a, oxide 530b, and oxide 530c), a conductor 542a that functions as one of the source or drain, It includes a conductor 542b which functions as the other of the source and the drain, and an insulator 544.

[0252] In addition, in the transistor 500A shown in FIGS. 16A, 16B, and 16C, the oxide 53 0c, an insulator 550, and a conductor 560 are inserted into an opening in the insulator 580. The oxide 530c, the insulator 550, and the conductor 560 are disposed through the insulating layer 544. is disposed between the conductor 542a and the conductor 542b.

[0253] The insulators 511 and 512 function as interlayer films.

[0254] The interlayer film may be silicon oxide, silicon oxynitride, silicon nitride oxide, or aluminum oxide. um, hafnium oxide, tantalum oxide, zirconium oxide, lead zirconate titanate (PZ T), strontium titanate (SrTiO3) or (Ba,Sr)TiO3 (BST) Insulators such as the above can be used in a single layer or a laminated layer. Aluminum oxide, bismuth oxide, germanium oxide, niobium oxide, silicon oxide, titanium oxide Tungsten, tungsten oxide, yttrium oxide, or zirconium oxide may be added. These insulators may be nitrided. Alternatively, silicon nitride may be laminated.

[0255] For example, the insulator 511 prevents impurities such as water or hydrogen from entering the transistor 500 from the substrate side. It is preferable that the insulating film functions as a barrier film to prevent the inclusion of A. 511 has the function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, and copper atoms. It is preferable to use an insulating material that is resistant to the penetration of the above impurities. For example, it has a function of suppressing the diffusion of at least one of oxygen atoms, oxygen molecules, etc. (see above). It is preferable to use an insulating material that is difficult for oxygen to permeate. Aluminum oxide or silicon nitride may be used as the material of the electrode 1. Impurities such as water are prevented from diffusing from the substrate side to the transistor 500A side by the insulator 511. It can be suppressed.

[0256] For example, it is preferable that the insulator 512 has a lower dielectric constant than the insulator 511. By using a material with a low conductivity as the interlayer film, the parasitic capacitance occurring between wirings can be reduced.

[0257] The conductor 505 is formed so as to be embedded in the insulator 512. The height of the upper surface of the conductor 505 can be made to be approximately the same as the height of the upper surface of the insulator 512. Although a single layer structure is shown, the present invention is not limited to this. For example, The conductor 505 may have a multilayer structure of two or more layers. It is preferable to use a conductive material having high conductivity, which is mainly composed of silicon, copper, or aluminum. stomach.

[0258] In transistor 500A, conductor 560 is a first gate (also called a top gate). The conductor 503 may function as a second gate (bottom gate). In this case, the electric potential applied to the conductor 503 may be The potential of the transistor 560 is changed independently of the potential applied to the conductor 560. In particular, applying a negative potential to the conductor 503 can control the threshold voltage of the conductor 500A. By doing so, the threshold voltage of the transistor 500A is increased to be greater than 0 V, thereby reducing the off-state current. Therefore, applying a negative potential to the conductor 503 is more effective. The drain current when the potential applied to the conductor 560 is 0 V is made smaller than when there is no potential. It is possible.

[0259] In addition, for example, by providing the conductor 503 and the conductor 560 so that they overlap with each other, the conductor 56 When a potential is applied to the conductor 503, the electric field generated by the conductor 560 and the conductor 5 The electric field generated by the oxide 530 is connected to the electric field generated by the oxide 530, and the electric field covers the channel forming region formed in the oxide 530. It is possible.

[0260] That is, the electric field of the conductor 560 functioning as the first gate electrode and the electric field of the second gate electrode The electric field of the conductor 503, which functions as an electrode, electrically connects the channel forming region. In this specification, the electric field of the first gate electrode and the electric field of the second gate electrode The structure of a transistor in which the channel formation region is electrically surrounded by a field is called a surrounding field. This is called the nded channel (S-channel) structure.

[0261] The insulators 514 and 516 are interlayer films, similar to the insulators 511 and 512. For example, the insulator 514 functions as a barrier to prevent impurities such as water or hydrogen from traversing the substrate side. It is preferable that the film functions as a barrier film that prevents the metal from being mixed into the transistor 500A. Due to the structure, impurities such as hydrogen and water can enter the transistor 500 from the substrate side rather than the insulator 514. In addition, for example, the insulator 516 can prevent the insulator 51 from diffusing to the side A. It is preferable that the relative dielectric constant is lower than that of 4. By using a material with a low relative dielectric constant as the interlayer film, The parasitic capacitance occurring between the lines can be reduced.

[0262] The conductor 503, which functions as a second gate, is located between the openings of the insulators 514 and 516. Conductor 503a is formed in contact with the inner wall, and conductor 503b is formed further inside. Here, the height of the upper surfaces of the conductors 503a and 503b and the height of the upper surface of the insulator 516 are In the transistor 500A, the conductor 503a and the conductor 50 3b are stacked, the present invention is not limited to this. For example, the conductor 503 may be provided as a single layer or a laminated structure of three or more layers.

[0263] Here, the conductor 503a is a diffusion layer for impurities such as hydrogen atoms, hydrogen molecules, water molecules, and copper atoms. It is preferable to use a conductive material that has the function of suppressing the impurities (i.e., the impurities are less likely to permeate). Alternatively, the diffusion of oxygen (for example, at least one of oxygen atoms, oxygen molecules, etc.) is suppressed. It is preferable to use a conductive material that has the above-mentioned function (i.e., that is difficult for oxygen to permeate). In this specification, the function of suppressing the diffusion of impurities or oxygen means the function of suppressing the diffusion of the above impurities or the above The function is to suppress the diffusion of any one or all of the oxygen.

[0264] For example, the conductor 503a has a function of suppressing the diffusion of oxygen, so that the conductor 503 This can prevent b from being oxidized and the electrical conductivity from decreasing.

[0265] When the conductor 503 also functions as a wiring, the conductor 503b is made of tungsten, copper, or the like. It is preferable to use a conductive material having high conductivity, such as aluminum or aluminum-based material. In this case, the conductor 505 is not necessarily provided. Although shown in the figure, it may have a laminated structure, for example, titanium, titanium nitride and the above conductive material. It may also be laminated.

[0266] The insulator 522 having a function as a second gate insulating film preferably has a barrier property. The insulator 522 has a barrier property, which prevents the transistor 500A from being exposed to the surrounding area. It functions as a layer that suppresses the intrusion of impurities such as hydrogen into the transistor 500A.

[0267] 16(B) and (C) show a three-layer laminated structure as the second gate insulating film. However, it may be a single layer, two layers, or a laminated structure of four or more layers. In that case, the layers must be made of the same material. The laminated structure is not limited to a laminated structure of the same material, but may be a laminated structure made of different materials.

[0268] The oxide 530 having a region that functions as a channel formation region is formed by an oxide 530a and an oxide The oxide 530b is on the oxide 530a, and the oxide 530c is on the oxide 530b. By having the oxide 530a under the oxide 530b, the oxide 530b is formed below the oxide 530a. The diffusion of impurities from the oxide 530b to the oxide 530b can be suppressed. By having oxide 530c on object 530b, the oxide 530c is formed above the oxide 530c. The diffusion of impurities from the structure to the oxide 530b can be suppressed. As the material, an oxide semiconductor, which is one of the above-mentioned metal oxides, can be used.

[0269] The oxide 530c is formed in the opening of the insulator 580 through the insulator 544. When the insulator 544 has a barrier property, the insulating material 544 is preferably provided as a barrier material. This can prevent impurities from diffusing into the oxide 530.

[0270] A conductor 542a serving as one of a source electrode and a drain electrode, The conductor 542b functioning as the other drain electrode is made of aluminum, titanium, chromium, or the like. , nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, or tungsten Metals such as stainless steel or alloys containing stainless steel as the main component can be used. Metal nitride films such as tantalum have barrier properties against hydrogen and oxygen and also have high oxidation resistance. Therefore, it is preferable.

[0271] Although a single layer structure is shown in FIG. 16(B), a laminated structure of two or more layers may also be used. For example, a tantalum nitride film and a tungsten film may be stacked. Alternatively, a two-layer structure in which an aluminum film is laminated on a tungsten film, or a copper film may be laminated on a tungsten film. - Two-layer structure with copper film laminated on magnesium-aluminum alloy film, copper film laminated on titanium film Alternatively, a two-layer structure in which a copper film is laminated on a tungsten film may be used.

[0272] Also, a titanium film or titanium nitride film and an aluminum film overlaid on the titanium film or titanium nitride film are used. A three-layer structure in which a titanium film or a copper film is laminated and a titanium film or a titanium nitride film is further formed on top of that. Molybdenum film or molybdenum nitride film and a An aluminum film or a copper film is laminated on top of it, and a molybdenum film or a molybdenum nitride film is further laminated on top of it. There are three-layer structures that form a transparent film. Transparent conductive materials may also be used.

[0273] A barrier layer may be provided over the conductor 542a and the conductor 542b. It is preferable to use a material that has a barrier property against oxygen or hydrogen. Therefore, when the insulator 544 is formed, the conductors 542a and 542b are oxidized. This can suppress the above.

[0274] The barrier layer may be made of, for example, a metal oxide, particularly aluminum oxide, Using insulating films such as hafnium oxide and gallium oxide that have barrier properties against oxygen and hydrogen It is also preferable to use silicon nitride formed by the CVD method.

[0275] The barrier layer widens the range of material choices for the conductor 542a and the conductor 542b. For example, the conductor 542a and the conductor 542b may be made of tungsten or aluminum. Materials with low oxidation resistance but high conductivity, such as aluminum, can be used. For example, a conductor that is easy to form or process can be used.

[0276] The insulator 550 functions as a first gate insulating film. The oxide 530c and the insulator 544 are provided in the opening formed in the preferable.

[0277] As transistors become smaller and more highly integrated, the gate insulating film becomes thinner, which increases leakage current. In this case, the insulator 550 may function as a second gate insulating film. Similarly, a laminated structure may be used. By using a laminated structure of a thermally stable material and a thin film of a thin film, It is possible to reduce the gate potential during transistor operation. It may have a laminated structure.

[0278] The conductor 560 functioning as the first gate electrode includes the conductor 560a and the conductor 560b. The conductor 560a has a conductor 560b on the conductor 503a. The conductor 560a is a hydrogen atom, similar to the conductor 503a. Conductive materials that have the function of suppressing the diffusion of impurities such as hydrogen molecules, water molecules, and copper atoms are used. It is preferable that the oxygen (for example, at least one of an oxygen atom, an oxygen molecule, etc.) It is preferable to use a conductive material that has the function of suppressing diffusion.

[0279] The conductor 560a has a function of suppressing the diffusion of oxygen, and therefore the material of the conductor 560b In other words, by having the conductor 560a, the conductor 560 The oxidation of b is suppressed, and the decrease in electrical conductivity can be prevented.

[0280] Examples of conductive materials that have the function of suppressing oxygen diffusion include tantalum and tantalum nitride. It is preferable to use ruthenium, ruthenium oxide, or the like. The oxide semiconductor that can be used as the oxide 530 can be used as a. In this case, the conductor 560b is formed by sputtering, and the electric It is possible to lower the resistance and make it a conductor. The electrode can be called a tor electrode.

[0281] The conductor 560b is made of a conductive material mainly composed of tungsten, copper, or aluminum. In addition, since the conductor 560 functions as a wiring, it has high conductivity. It is preferable to use a conductor. The conductor 560b may have a layered structure, for example, Alternatively, a laminate of titanium, titanium nitride and the above conductive material may be used.

[0282] An insulator 544 is disposed between the insulator 580 and the transistor 500A. 4 uses an insulating material that has the function of suppressing the diffusion of impurities such as water or hydrogen, and oxygen. For example, it is preferable to use aluminum oxide or hafnium oxide. In addition, other oxides such as magnesium oxide, gallium oxide, germanium oxide, and yttrium oxide are also available. gold, such as tritium oxide, zirconium oxide, lanthanum oxide, neodymium oxide or tantalum oxide; Metal oxides, silicon nitride oxide, silicon nitride, or the like can be used.

[0283] By including the insulator 544, impurities such as water and hydrogen contained in the insulator 580 are converted into acids. The oxide 530c is prevented from diffusing into the oxide 530b through the insulator 550. In addition, the excess oxygen contained in the insulator 580 can prevent the conductor 560 from being oxidized. It is possible.

[0284] The insulators 580, 574, and 581 function as interlayer films.

[0285] The insulator 574, like the insulator 514, prevents impurities such as water or hydrogen from entering the transformer from the outside. It is preferable that the insulating film functions as a barrier insulating film that prevents the metal from being mixed into the transistor 500A.

[0286] In addition, the insulators 580 and 581 are thicker than the insulator 574, similar to the insulator 516. By using a material with a low dielectric constant as the interlayer film, The resulting parasitic capacitance can be reduced.

[0287] The transistor 500A is embedded in an insulator 580, an insulator 574, and an insulator 581. Electrical connection with other structures is established through plugs and wiring such as embedded conductors 540a and 540b. They may also be electrically connected.

[0288] As for the material of the conductor 540a and the conductor 540b, similarly to the conductor 503, Conductive materials such as metal materials, alloy materials, metal nitride materials, or metal oxide materials are deposited in a single layer or For example, tungsten and molybdenum, which have both heat resistance and electrical conductivity, can be used. It is preferable to use a high melting point material such as butanol, or a low resistance material such as aluminum or copper. It is preferable to form the wiring from a conductive material. By using a low-resistance conductive material, the wiring resistance can be reduced. It is possible.

[0289] For example, the conductor 540a and the conductor 540b may be, for example, hydrogen and oxygen. The compound of tantalum nitride, which is a conductor with barrier properties, and tungsten, which has high conductivity, By using a layered structure, the conductivity of the wiring is maintained while preventing the diffusion of impurities from the outside. It can be suppressed.

[0290] By having the above structure, a transistor including an oxide semiconductor and having a large on-state current can be provided. Alternatively, a semiconductor device including an oxide semiconductor having a low off-state current can be provided. It is possible to provide a semiconductor device having a transistor, or to suppress fluctuations in electrical characteristics. As a result, it is possible to provide a semiconductor device having stable electrical characteristics and improved reliability. Cut.

[0291] <<Transistor structure example 2>> A structural example of the transistor 500B will be described with reference to FIGS. FIG. 17A is a top view of the transistor 500B. 17(C) is a cross-sectional view of the area indicated by the dashed line L1-L2 in FIG. 17A is a cross-sectional view of the portion indicated by the line W1-W2. For this reason, some elements are omitted from the illustration.

[0292] The transistor 500B is a modified example of the transistor 500A. To avoid confusion, differences from transistor 500A will be mainly described.

[0293] The transistor 500B includes a conductor 542a (conductor 542b), an oxide 530c, and The insulator 550 and the conductor 560 overlap each other. It is possible to provide a transistor with a high on-state current. can be provided.

[0294] The conductor 560 functioning as the first gate electrode includes the conductor 560a and the conductor 560b. The conductor 560a has a conductor 560b on the conductor 503a. The conductor 560a is a hydrogen atom, similar to the conductor 503a. Conductive materials that have the function of suppressing the diffusion of impurities such as hydrogen molecules, water molecules, and copper atoms are used. It is preferable that the oxygen (for example, at least one of an oxygen atom, an oxygen molecule, etc.) It is preferable to use a conductive material that has the function of suppressing diffusion.

[0295] The conductor 560a has a function of suppressing the diffusion of oxygen, and therefore the material of the conductor 560b In other words, by having the conductor 560a, the conductor 560 The oxidation of b is suppressed, and the decrease in electrical conductivity can be prevented.

[0296] In addition, the top and side surfaces of the conductor 560, the side surface of the insulator 550, and the side surface of the oxide 530c It is preferable to provide an insulator 544 so as to cover the insulating layer 544. It is preferable to use an insulating material that has the function of suppressing the diffusion of impurities such as hydrogen and oxygen. For example, it is preferable to use aluminum oxide or hafnium oxide. Also, for example, magnesium oxide, gallium oxide, germanium oxide, yttrium oxide metal oxides such as zirconium oxide, lanthanum oxide, neodymium oxide or tantalum oxide; Silicon nitride oxide, silicon nitride, or the like can be used.

[0297] By providing the insulator 544, oxidation of the conductor 560 can be suppressed. By providing the insulator 544, impurities such as water and hydrogen contained in the insulator 580 can be prevented from being transferred to the transistor. This can prevent the light from diffusing to the star 500B.

[0298] The contact plug of the transistor 500B is connected to the contact plug of the transistor 500A. The transistor 500B has a different structure from the contact plug. Between the conductor 546a (conductor 546b) and the insulator 580, there is provided a barrier An insulator 576a (insulator 576b) is disposed. ) is provided, the oxygen in the insulator 580 reacts with the conductor 546, and the conductor 546 is oxidized. This can prevent this from happening.

[0299] In addition, by providing an insulator 576a (insulator 576b) having a barrier property, plugs and The range of materials that can be selected for the conductors used for wiring can be expanded. For example, the conductor 546a (Conductor 546b) is made of a metal material that has the property of absorbing oxygen and is highly conductive. By using tungsten, a semiconductor device with low power consumption can be provided. Alternatively, a material having low oxidation resistance but high conductivity, such as aluminum, can be used. Furthermore, for example, a conductor that is easy to form a film or process can be used.

[0300] <<Transistor structure example 3>> An example of the structure of the transistor 500C will be described with reference to FIGS. FIG. 18A is a top view of the transistor 500C. FIG. 18B is a top view of the transistor 500C shown in FIG. 18(C) is a cross-sectional view of the area indicated by the dashed line L1-L2 in FIG. 18(A) is a cross-sectional view of the portion indicated by the line W1-W2. For this reason, some elements are omitted from the illustration.

[0301] Transistor 500C is a modified version of transistor 500A. To avoid confusion, differences from transistor 500A will be mainly described.

[0302] The transistor 500C shown in FIGS. 18A, 18B, and 18C includes a conductor 542a and an oxide. A conductor 547a is disposed between the conductor 542b and the oxide 530b. The conductor 542a (conductor 542b) is disposed on the conductive layer 547b. The oxide layer extends beyond the top surface of the conductive body 547a (the conductive body 547b) and the side surface of the conductive body 560. The conductor 547a and the conductor 547b have a region in contact with the upper surface of the conductor 530b. Any conductor that can be used for the conductor 542a and the conductor 542b may be used. Furthermore, the film thickness of the conductor 547a and the conductor 547b is at least equal to that of the conductor 542a and the conductor 542b. It is preferably thicker than conductor 542b.

[0303] The transistor 500C shown in FIGS. 18A, 18B, and 18C has the above-described structure. By having the above, the conductor 542a and the conductor 542b are The end of the conductor 542a and the end of the conductor 542a can be brought close to the conductor 560. The end of b can overlap with the conductor 560. It is possible to shorten the effective channel length, improve the on-current, and improve the frequency characteristics. Cut.

[0304] In addition, the conductor 547a (conductor 547b) overlaps with the conductor 542a (conductor 542b). By adopting such a configuration, the conductor 540a (the conductor In the etching to form the opening in which the conductor 547a (conductor 540b) is embedded, 47b) acts as a stopper to prevent over-etching of oxide 530b. It is possible.

[0305] In addition, the transistor 500C shown in FIGS. 18A, 18B, and 18C includes an insulator 544 The insulator 544 may be water or Impurities such as hydrogen and excess oxygen enter the transistor 500C from the insulator 580 side. It is preferable that the insulator 545 functions as a barrier insulating film that suppresses the generation of the insulating film. The insulator that can be used for the insulator 544 can be used. Examples of the nitride include aluminum nitride, aluminum titanium nitride, titanium nitride, and silicon nitride. Alternatively, a nitride insulator such as silicon oxynitride may be used.

[0306] The transistor 500C shown in FIGS. 18A, 18B, and 18C has the same structure as that shown in FIG. Unlike the transistor 500A shown in (B) and (C), the conductor 503 is set to have a single-layer structure. In this case, an insulating layer, which becomes an insulator 516, may be formed on the patterned conductor 503. The upper part of the insulating film is removed by a CMP method or the like until the upper surface of the conductor 503 is exposed. Here, it is preferable to improve the flatness of the upper surface of the conductor 503. For example, the average surface roughness (Ra) of the upper surface of the conductor 503 is set to 1 nm or less, preferably 0.5 nm or less. The thickness may be 0.3 nm or less, more preferably 0.3 nm or less. The planarity of the insulating layer is improved, and the crystallinity of the oxide 530b and the oxide 530c is improved. It is possible to aim higher.

[0307] <<Transistor structure example 4>> An example of the structure of the transistor 500D will be described with reference to FIGS. FIG. 19A is a top view of a transistor 500D. 19(C) is a cross-sectional view of the area indicated by the dashed line L1-L2 in FIG. 19(A) is a cross-sectional view of the portion indicated by the line W1-W2. For this reason, some elements are omitted from the illustration.

[0308] The transistor 500D is connected to the transistors 500A, 500B, and It has a different structure from the 500C. Therefore, to avoid repetition, we will mainly focus on the The content overlaps with transistor 500A, transistor 500B, and transistor 500C. Therefore, a detailed description will be omitted and only the differences will be explained.

[0309] The transistor 500D shown in FIGS. 19A to 19C is the same as that shown in FIGS. Similarly to the transistor 500C shown in Fig. 5C, the conductor 505 is not provided, and the second gate and The conductor 503, which functions as a wiring, is also used as a wiring. The metal oxide 552 is formed on the insulator 550. A conductor 560 is provided on the object 552, and an insulator 570 is provided on the conductor 560. An insulator 571 is provided on the body 570 .

[0310] The metal oxide 552 preferably has a function of suppressing oxygen diffusion. By providing a metal oxide 552 between the conductive material 560 and the conductive material 560, which suppresses the diffusion of oxygen, The diffusion of oxygen into the dielectric 560 is suppressed. In other words, the amount of oxygen supplied to the oxide 530 is reduced. In addition, oxidation of the conductor 560 by oxygen can be suppressed. .

[0311] Note that the metal oxide 552 may function as a part of the first gate. The oxide semiconductor that can be used as the oxide 530 is used as the metal oxide 552. In this case, the conductor 560 can be formed by sputtering to form a metal oxide film. The electrical resistance of the oxide 552 can be reduced to form a conductive layer. e Conductor) electrode.

[0312] The metal oxide 552 may also function as a part of the gate insulating film. Therefore, when silicon oxide or silicon oxynitride is used for the insulator 550, the metal oxide The material 552 is preferably a metal oxide, which is a high-k material having a high dielectric constant. This laminated structure is stable against heat and has a high dielectric constant. Therefore, the gate voltage applied during transistor operation can be adjusted while maintaining the physical film thickness. In addition, the equivalent oxide thickness ( It is possible to reduce the thickness of the EOT.

[0313] Although the metal oxide 552 in the transistor 500D is shown as a single layer, it may be a stack of two or more layers. For example, a metal oxide that functions as a part of the gate electrode and a gate insulating film may be used. A metal oxide that functions as part of the film may be laminated.

[0314] When the metal oxide 552 functions as a gate electrode, It is possible to improve the on-state current of transistor 500D without weakening the influence of these electric fields. Alternatively, when it functions as a gate insulating film, the insulator 550 and the metal oxide 552 The physical thickness of the oxide 530 keeps the distance between the conductor 560 and the oxide 530. The leakage current between the insulator 560 and the oxide 530 can be suppressed. 550 and the metal oxide 552 are stacked, the conductor 560 and the oxide 53 0 and the electric field strength applied from the conductor 560 to the oxide 530. can be adjusted appropriately.

[0315] Specifically, by reducing the resistance of an oxide semiconductor that can be used for the oxide 530, Metal oxide 552 can be used. Alternatively, hafnium, aluminum, gallium, Aluminum, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium Metal oxide containing one or more metals selected from the group consisting of nium, magnesium, etc. can be used.

[0316] In particular, an insulating layer containing oxides of either or both of aluminum and hafnium is used. Aluminum oxide, hafnium oxide, oxides containing aluminum and hafnium (hafnium It is preferable to use hafnium aluminate. In particular, hafnium aluminate is an oxide. It has higher heat resistance than hafnium film. Therefore, it does not crystallize during heat treatment in the subsequent process. It is preferable because it is difficult to form a metal oxide film. It can be designed appropriately depending on the starter characteristics.

[0317] The insulator 570 is an insulating material having a function of suppressing the permeation of impurities such as water or hydrogen, and oxygen. It is advisable to use insulating materials such as aluminum oxide or hafnium oxide. This prevents the conductor 560 from being oxidized by oxygen from above the insulator 570. In addition, impurities such as water or hydrogen from above the insulator 570 can be prevented. The impurities are prevented from being mixed into the oxide 530 through the conductor 560 and the insulator 550. It is possible.

[0318] The insulator 571 functions as a hard mask. When processing 60, the side of the conductor 560 is approximately perpendicular, specifically, the side of the conductor 560 and the substrate The angle formed by the plate surface is 75 degrees or more and 100 degrees or less, preferably 80 degrees or more and 95 degrees or less. This can be done.

[0319] The insulator 571 has a function of suppressing the permeation of impurities such as water or hydrogen, and oxygen. By using an insulating material having the following properties, the insulating material may also function as a barrier layer. The insulator 570 may not be provided.

[0320] The insulator 571 is used as a hard mask to form the insulator 570, the conductor 560, and the metal oxide 552, insulator 550, and oxide 530c are selectively removed to remove these The side surfaces can be made substantially flush and part of the surface of oxide 530b can be exposed.

[0321] Transistor 500D also has regions 531a and 531b on the exposed oxide 530b surface. One of the regions 531a and 531b functions as a source region. The other serves as the drain region.

[0322] The regions 531a and 531b are formed by, for example, an ion implantation method or an ion doping method. , plasma immersion ion implantation, or plasma treatment, etc., to remove the exposed oxide. This can be achieved by introducing impurity elements such as phosphorus or boron into the surface of 530b. In the embodiments, the term "impurity elements" refers to elements other than the main component elements.

[0323] In addition, after exposing a part of the surface of the oxide 530b, a metal film is formed and then heat-treated. By this, the elements contained in the metal film are diffused into the oxide 530b, and the regions 531a and Region 531b may also be formed.

[0324] The region of the oxide 530b into which the impurity element is introduced has a reduced electrical resistivity. The regions 531a and 531b may be referred to as "impurity regions" or "low-resistance regions."

[0325] By using the insulator 571 and / or the conductor 560 as a mask, the regions 531a and The region 531b can be formed in a self-aligned manner. The region 531a and / or the region 531b do not overlap with the conductor 560, thereby reducing the parasitic capacitance. In addition, the channel forming region and the source / drain region (region 531a or region 53 1b), no offset region is formed between the regions 531a and 531b. (Self-aligned) formation increases on-current and reduces threshold voltage , and can achieve improvements in operating frequency.

[0326] In order to further reduce the off-state current, an off-state current is formed between the channel forming region and the source / drain region. An offset region is a region having a high electrical resistivity, and The offset region is a region where the introduction of the impurity element is not performed. This can be achieved by introducing the impurity element described above after the formation of the insulator 5. The insulating layer 75 functions as a mask in the same manner as the insulating layer 571. Impurity elements are not introduced into the region overlapping with the body 575, and the electrical resistivity of the region remains high. It is possible.

[0327] The transistor 500D also includes an insulator 570, a conductor 560, a metal oxide 552, ... The insulating layer 575 is disposed on the side of the insulating layer 550 and the oxide layer 530c. It is preferable to use an insulator with a low dielectric constant. For example, silicon oxide, silicon oxynitride, or nitride silicon oxide, silicon nitride, fluorine-doped silicon oxide, carbon-doped silicon oxide Silicon, carbon and nitrogen doped silicon oxide, porous silicon oxide, or resin In particular, silicon oxide, silicon oxynitride, and silicon nitride oxide are preferable. When silicon oxide having vacancies is used for the insulator 575, the insulator 575 is filled with silicon dioxide in a later process. This is preferable because an oxygen-excess region can be easily formed. The insulator 575 is preferably made of silicon because it is thermally stable. It is preferable to do so.

[0328] Transistor 500D also includes insulator 575 and insulator 544 on oxide 530. The insulator 544 is preferably formed by sputtering. By using this method, it is possible to form an insulator film with few impurities such as water or hydrogen. For example, the insulator 544 may be made of aluminum oxide.

[0329] The oxide film formed by sputtering extracts hydrogen from the structure on which the film is to be formed. Therefore, the insulator 544 may trap hydrogen and water from the oxide 530 and the insulator 575. The absorption can reduce the hydrogen concentration in the oxide 530 and the insulator 575.

[0330] <<Transistor structure example 5>> A structural example of the transistor 500E will be described with reference to FIGS. 20A to 20C. FIG. 20(A) is a top view of the transistor 500E. 20(C) is a cross-sectional view of the portion indicated by the dashed line L1-L2 in FIG. 20(A) is a cross-sectional view of the portion indicated by W1-W2. For this reason, some elements are omitted in the illustration.

[0331] The transistor 500E is a transistor 500A, a transistor 500B, a transistor 500C and transistor 500D have different structures. To prevent this, transistors 500A, 500B, and 500C The explanation of the overlapping points with the transistor 500D will be omitted, and the differences will be mainly explained. and explain.

[0332] In FIGS. 20A, 20B, and 20C, a conductor 542a and a conductor 542b are provided. The exposed oxide 530b has regions 531a and 531b on its surface. One of the regions 531a and 531b functions as a source region, and the other functions as a drain region. In addition, an insulator 573 is provided between the oxide 530b and the insulator 544.

[0333] The regions 531a and 531b shown in FIG. 20B are formed by adding the following element to the oxide 530b: The regions 531a and 531b are regions where silicon is added. For example, the regions 531a and 531b are dummy gates. It can be formed by using

[0334] Specifically, a dummy gate is provided on the oxide 530b, and the dummy gate is used as a mask. It is preferable to use the oxide 530b as a thin film and add an element that reduces the resistance of a part of the oxide 530b. The element is added to the region of the oxide 530a and the region of the oxide 530b that do not overlap with the dummy gate. The element is added to form the regions 531a and 531b. is an ion implantation method in which ionized source gas is mass-separated and added, and Plasma immersion ion impingement is an ion doping method that adds gas without mass separation. The oration method can be used.

[0335] A representative example of an element that reduces the resistance of a portion of the oxide 530b is boron. or phosphorus. Also, hydrogen, carbon, nitrogen, fluorine, sulfur, chlorine, titanium, rare gases Typical examples of rare gases include helium, neon, argon, and crypto The concentration of these elements is measured by secondary ion mass spectrometry (SIMS:Se Condensed Ion Mass Spectrometry (CIMMS) is used to measure That's fine.

[0336] In particular, Si transistors containing amorphous silicon or low-temperature polysilicon in the semiconductor layer Boron and phosphorus can be added in the equipment of the production line of the By using the equipment of the production line, it is possible to reduce the resistance of a part of the oxide 530b. In other words, part of the Si transistor manufacturing line is used for the manufacturing process of the transistor 500E. It can be used for.

[0337] Subsequently, an insulating film that will become an insulator 573 and an insulating film are formed on the oxide 530b and the dummy gate. An insulating film that becomes the insulator 544 may be formed. 4, the insulating film 531a or 531b and the oxide 53 An overlapping region between Oc and the insulator 550 can be provided.

[0338] Specifically, after forming an insulating film that will become the insulator 580 on the insulating film that will become the insulator 544, The insulating film that will become the insulating film 580 is subjected to CMP (Chemical Mechanical Polishing). By performing a dummy gate etching process, a part of the insulating film that will become the insulator 580 is removed. Subsequently, when the dummy gate is removed, the insulator 57 in contact with the dummy gate is removed. Therefore, the side of the opening in the insulator 580 is covered with insulating material. The insulating layer 544 and the insulating layer 573 are exposed, and the insulating layer 544 and the insulating layer 573 are exposed at the bottom of the opening. Next, a part of each of the regions 531a and 531b is exposed through the opening. The oxide film that becomes the oxide 530c, the insulating film that becomes the insulator 550, and the conductive film that becomes the conductor 560 are After the films are formed in order, the oxide 530 is removed by a CMP process or the like until the insulator 580 is exposed. c, the insulating film that will become the insulator 550, and a part of the conductive film that will become the conductor 560. By removing the insulating layer, the transistors shown in FIGS. 20(A), (B), and (C) can be formed. can.

[0339] Note that the insulator 573 and the insulator 544 are not essential components. The design can be adjusted depending on the requirements.

[0340] The transistors shown in FIGS. 20A, 20B, and 20C include a conductor 542a and a conductor Since the body 542b is not provided, the cost for manufacturing the transistor can be reduced. can be done.

[0341] <<Transistor structure example 6>> 15(A)(B), the conductor 560 that functions as a gate is an insulating The structure formed inside the opening of the conductive body 580 has been described. A structure in which the insulator is provided above such a transistor can also be used. Examples of the structure are shown in Figures 21(A) and 21(B) and Figures 22(A) and 22(B).

[0342] FIG. 21(A) is a top view of a transistor, and FIG. 21(B) is a perspective view of the transistor. 22(A) shows a cross section of L1-L2 in FIG. 21(A), and A cross-sectional view of 2 is shown in FIG.

[0343] The transistors shown in FIGS. 21(A) and 21(B) and 22(A) and 22(B) have a back gate. The BGE is a conductor having the function of a gate insulating film, the BGI is an insulator having the function of a gate insulating film, and the BGI is an oxide. a compound semiconductor S, an insulator FGI having a function as a gate insulating film, and a front gate. and a conductor WE having a function as a wiring. In addition, the conductor PE is a mixture of the conductor WE, the oxide S, the conductor BGE, or the conductor FGE, In this case, the oxide semiconductor S has a function as a plug for connecting the An example is shown in which the oxide layers S1, S2 and S3 are formed.

[0344] Note that this embodiment mode can be appropriately combined with other embodiment modes shown in this specification. do.

[0345] (Fourth embodiment) In this embodiment, the semiconductor device can be used for the OS transistor described in the above embodiment. CAC-OS (Cloud-Aligned Composite Silicon) is a metal oxide Oxide Semiconductor), and CAAC-OS(c-axis Al Ignition Crystalline Oxide Semiconductor In the specification, CAC is used to describe an example of the function or material configuration. CAAC represents an example of a crystal structure.

[0346] <Metal oxide composition> CAC-OS or CAC-metal oxide is a material that has the function of conductivity in some parts. The material has an insulating function in part and a semiconductor function in the whole. In addition, CAC-OS or CAC-metal oxide is used as the active layer of a transistor. When used, the conductive function is the function of allowing electrons (or holes) to flow as carriers, and the insulating function is the function of allowing electrons (or holes) to flow as carriers. The insulating function is the function of preventing the flow of electrons that act as carriers. By making these functions work complementarily, the switching function (On / Off) The function of making it possible to make CAC-OS or CAC-metal oxide In CAC-OS or CAC-metal oxide, each function is separated. By combining these, the functions of both can be maximized.

[0347] In addition, CAC-OS or CAC-metal oxide has a conductive region and an insulating region. The conductive region has the above-mentioned conductive function, and the insulating region has the above-mentioned insulating function. In addition, the conductive region and the insulating region are formed at the nanoparticle level in the material. The conductive and insulating regions may be separated by a thin film. In addition, the conductive area may be observed as a cloud-like connected area with a blurred periphery. This may be the case.

[0348] In addition, in the CAC-OS or CAC-metal oxide, a conductive region and an insulating region are The peripheral region is 0.5 nm to 10 nm, preferably 0.5 nm to 3 nm. The following sizes may be dispersed in the material:

[0349] In addition, CAC-OS and CAC-metal oxide have different band gaps. For example, CAC-OS or CAC-metal oxide e is a component with a wide gap due to the insulating region and a narrow gap due to the conductive region. In this configuration, when a carrier is flowed, In the component with a narrow gap, carriers mainly flow. The component having a narrow gap acts complementary to the component having a wide gap. Carriers also flow to the wide gap component in conjunction with the CA component. C-OS or CAC-metal oxide is used for the channel formation region of the transistor. When the transistor is turned on, the transistor has a high current driving capability, i.e., a large on-state current. High field effect mobility can be obtained.

[0350] That is, CAC-OS or CAC-metal oxide is a matrix composite material. (matrix composite), or metal matrix composite It can also be called atrix composite.

[0351] <Metal oxide structure> Oxide semiconductors are divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. As a non-single-crystal oxide semiconductor, for example, CAAC-OS (c-axis oriented crystal-coated oxide semiconductor) igned crystalline oxide semiconductor), Crystalline oxide semiconductor, nc-OS (nanocrystalline oxide semiconductor) semiconductor), pseudo-amorphous oxide semiconductor (a-like OS) amorphous-like oxide semiconductors and amorphous oxide semiconductors etc.

[0352] CAAC-OS has a c-axis orientation and multiple nanocrystals are connected in the ab-plane direction. The crystal structure is distorted by the connection of multiple nanocrystals. In the region, the lattice arrangement is changed between a region with a uniform lattice arrangement and another region with a uniform lattice arrangement. This refers to the point where the direction of the

[0353] Nanocrystals are basically hexagonal, but are not limited to regular hexagonal shapes. They may also have non-regular hexagonal shapes. In addition, the distortion may have lattice arrangements such as pentagons and heptagons. In CAAC-OS, clear grain boundaries (grain boundaries) are observed even near the strain. It is not possible to confirm the grain boundary (also called grain boundary distortion) due to the distortion of the lattice arrangement. This is because the CAAC-OS has a high SiO2 content in the ab-plane direction. The oxygen atoms are not densely packed, and the bond distance between atoms changes due to the substitution of metal elements. This is thought to be because distortion can be tolerated by, for example, increasing the thickness.

[0354] In addition, the CAAC-OS has a layer containing indium and oxygen (hereinafter referred to as an In layer) and an element A layered crystal structure consisting of layers containing M, zinc, and oxygen (hereinafter referred to as the (M,Zn) layer). (also called layer structure). Indium and element M are mutually substitutable. When the element M in the (M,Zn) layer is replaced with indium, the (In,M,Zn) layer Also, when indium in the In layer is substituted with element M, (In,M) It can also be expressed as a layer.

[0355] CAAC-OS is an oxide semiconductor with high crystallinity. Since it is not possible to confirm the grain boundaries, the decrease in electron mobility caused by the grain boundaries occurs. In addition, the crystallinity of oxide semiconductors can be affected by impurities and defects. Therefore, CAAC-OS is an oxidized material with few impurities and defects (such as oxygen vacancies). Therefore, oxide semiconductors with CAAC-OS have stable physical properties. Therefore, oxide semiconductors having CAAC-OS are heat-resistant and highly reliable. In addition, CAAC-OS is designed to withstand the high temperatures (so-called thermal budget) in the manufacturing process. Therefore, when a CAAC-OS is used for an OS transistor, This allows for greater freedom.

[0356] nc-OS is a material that can be used in microscopic areas (e.g., areas between 1 nm and 10 nm, especially areas between 1 nm and 10 nm). The atomic arrangement is periodic in the region of 3 nm or less. There is no regularity in the crystal orientation between the crystals. Therefore, no orientation is observed throughout the film. Therefore, depending on the analytical method, nc-OS may be classified as a-like OS or amorphous oxide semiconductor. It may be indistinguishable from the body.

[0357] The a-like OS is an oxide semiconductor with a structure between the nc-OS and amorphous oxide semiconductor. A-like OS has pores or low density regions. The OS has lower crystallinity than the nc-OS and CAAC-OS.

[0358] Oxide semiconductors have a variety of structures, each of which has different characteristics. The oxide semiconductors in The compound may have two or more of the c-OS and CAAC-OS.

[0359] <Transistors containing oxide semiconductors> Next, a case where the oxide semiconductor is used in a transistor will be described.

[0360] By using the oxide semiconductor for a transistor, a transistor with high field-effect mobility can be realized. Furthermore, a highly reliable transistor can be realized.

[0361] In addition, an oxide semiconductor with a low carrier concentration is preferably used for the transistor. When the carrier concentration of the oxide semiconductor film is reduced, the impurity concentration in the oxide semiconductor film is In this specification and the like, the impurity concentration is low, and the defect level density is low. A low density of defect states is called high purity intrinsic or substantially high purity intrinsic. Conductors have a carrier concentration of 8×10 11 cm -3 Less than 1 x 10 11 cm -3 Not yet less than 1×10 10 cm -3 Less than 1 x 10-9 cm -3 That's all. That's fine.

[0362] Furthermore, a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has a low density of defect states. Therefore, the trap level density may also be low.

[0363] In addition, the time required for the charges trapped in the trap levels of the oxide semiconductor to disappear is Therefore, the trap level density is high. A transistor in which a channel formation region is formed in an oxide semiconductor has unstable electrical characteristics. This may be the case.

[0364] Therefore, in order to stabilize the electrical characteristics of a transistor, the impurity concentration in the oxide semiconductor In addition, in order to reduce the impurity concentration in the oxide semiconductor, It is preferable to reduce the impurity concentration in the adjacent film. These include alkali metals, alkaline earth metals, iron, nickel, and silicon.

[0365] <Impurities> Here, the influence of each impurity in an oxide semiconductor will be described.

[0366] When oxide semiconductors contain silicon or carbon, which are elements of Group 14, they are oxidized. Defect levels are formed in semiconductors, which is why defects in silicon and carbon in oxide semiconductors The concentration of silicon and carbon near the interface with the oxide semiconductor (Secondary Ion Mass Spectrometry) (SIMS: Secondary Ion Mass Spectrometry) The concentration obtained is 2 x 10 18 atoms / cm 3 Less than or equal to 2 x 1017 a toms / cm 3 The following applies.

[0367] In addition, when an oxide semiconductor contains an alkali metal or an alkaline earth metal, defect levels are formed. Therefore, alkali metals or alkaline earth metals may be included. Transistors using oxide semiconductors, which are widely used in semiconductors, tend to be normally on. Therefore, it is preferable to reduce the concentration of alkali metals or alkaline earth metals in the oxide semiconductor. Specifically, the alkali metal or alkali metal in the oxide semiconductor obtained by SIMS The concentration of earth metals is 1×10 18 atoms / cm 3 Less than or equal to 2 x 10 16 at oms / cm 3 Do the following:

[0368] In addition, when nitrogen is contained in an oxide semiconductor, electrons that serve as carriers are generated, and As a result, the nitrogen-containing oxide semiconductor becomes a semiconductor. Therefore, the transistor used in the oxide semiconductor tends to be normally on. In this case, it is preferable that the nitrogen content is reduced as much as possible. For example, the nitrogen content in the oxide semiconductor is The concentration is 5×10 19 atoms / cm 3 Less than 5 x 10 18 atoms / cm 3 Less than or equal to 1×10 18 atoms / cm 3 Below, More preferably 5×10 17 atoms / cm 3 The following applies.

[0369] In addition, hydrogen contained in oxide semiconductors reacts with oxygen that bonds with metal atoms to form water. When hydrogen enters the oxygen vacancy, the electron carrier In addition, some of the hydrogen atoms may bond with the oxygen atoms that bond with the metal atoms, forming chiral ions. Therefore, it is necessary to use an oxide semiconductor containing hydrogen. Therefore, the hydrogen in the oxide semiconductor tends to cause a transistor to be normally on. It is preferable that the amount of Si in the oxide semiconductor is as small as possible. The hydrogen concentration obtained by MS was 1×10 20 atoms / cm 3 Less than 1x, preferably 10 19 atoms / cm 3 less than 5 × 10 18 atoms / cm 3 less than , and more preferably 1 × 10 18 atoms / cm 3 Less than.

[0370] By using an oxide semiconductor with sufficiently reduced impurities for a channel formation region of a transistor, This makes it possible to impart stable electrical properties.

[0371] Note that this embodiment mode can be appropriately combined with other embodiment modes shown in this specification. do.

[0372] (Embodiment 5) In this embodiment, a product in which the semiconductor device described in the above embodiment is applied to an electronic device is provided. An example will be described.

[0373] <Notebook personal computer> The semiconductor device of one embodiment of the present invention can be applied to a display included in an information terminal device. FIG. 23(A) shows a notebook personal computer, which is a type of information terminal device. The device includes a housing 5401, a display unit 5402, a keyboard 5403, a pointing device It has the 5404 etc.

[0374] <Smartwatch> The semiconductor device of one embodiment of the present invention can be applied to a wearable terminal. B) is a smart watch, which is a type of wearable terminal, and includes a housing 5901, a display unit 5 902, operation buttons 5903, operators 5904, bands 5905, etc. The display unit 5902 may be configured to use a display device with a position input function. In addition, the function as a position input device can be added by providing a touch panel to the display device. Alternatively, the function as a position input device can be called a photosensor. It can also be added by providing a photoelectric conversion element in the pixel portion of the display device. Button 5903 is the power switch to start the smartwatch and the smartwatch app buttons for operating the application, volume adjustment buttons, or turning on or off the display unit 5902 In addition, the smart switch shown in FIG. The number of operation buttons 5903 on the smartwatch is two, but The number of operation buttons to be operated is not limited to this. The operator 5904 also functions as a crown for adjusting the time. In addition, it can also be used as an input interface for operating smartwatch applications. In the smart watch shown in FIG. 23(B), the operation button 59 However, the present invention is not limited to this configuration and may be configured without the operator 5904. It's okay to have one.

[0375] <Video camera> The semiconductor device of one embodiment of the present invention can be applied to a video camera. The video camera shown in FIG. 5 includes a first housing 5801, a second housing 5802, a display unit 5803, and an operation key. The operation keys 5804 and the lens 5805 are connected to the connector 5806. 5805 is provided in the first housing 5801, and the display unit 5803 is provided in the second housing 5802. The first housing 5801 and the second housing 5802 are connected by a connection part 5806. The angle between the first housing 5801 and the second housing 5802 is The image on the display unit 5803 can be changed by the first It may be configured to switch according to the angle between the housing 5801 and the second housing 5802.

[0376] <Mobile phone> The semiconductor device of one embodiment of the present invention can be applied to a mobile phone. This is a mobile phone having an information terminal function, and includes a housing 5501, a display unit 5502, a microphone 550 3, a speaker 5504, and an operation button 5505. Also, the display unit 5502 has a position input A display device with a function as a position input device may be used. The functionality of the display device can be added by providing a touch panel. Alternatively, the function as a position input device is to use a photoelectric conversion element, also called a photosensor, on the display device. It can also be added by providing it in the pixel portion of the operation button 5505. The power switch to start the conversation, the buttons to operate the mobile phone's applications, the volume control buttons The display unit 5502 may be provided with a button or a switch for turning on or off the display unit 5502. This can be done.

[0377] In addition, the mobile phone shown in FIG. 23(D) has two operation buttons 5505. However, the number of operation buttons on a mobile phone is not limited to this. The mobile phone shown in FIG. 23(D) is a light-emitting device for use as a flashlight or illumination. The configuration may include the following.

[0378] <Home video game console> The semiconductor device of one embodiment of the present invention is applied to a stationary game machine, which is an example of a game machine. In FIG. 23(E), a game console main body 7520 and 7522. The game console 7520 may include a wireless or wired The controller 7522 can be connected by a wire. However, the controller 7522 has a display that displays game images and inputs other than buttons. The interface includes touch panels, sticks, rotary knobs, and sliding knobs. The controller 7522 is not limited to the shape shown in FIG. The shape of the controller 7522 can be changed in various ways depending on the game genre. For example, in shooter games such as FPS (First Person Shooter), In gaming, triggers are used as buttons and controllers shaped like guns are used. For example, in music games, controllers with shapes that resemble musical instruments and other musical equipment can be used. Furthermore, the stationary game console does not use a controller, but Instead, it is equipped with a camera, depth sensor, microphone, etc. to capture the game player's gestures. The device may be operated by a finger and / or voice.

[0379] <Handheld game console> The semiconductor device of one embodiment of the present invention can be applied to a portable game machine, which is an example of a game machine. The portable game machine shown in FIG. 23(F) includes a housing 5201, a display portion 5202, and a button 5203. 203, etc. Note that the portable game machine shown in FIG. 23(F) is an example and is not an embodiment of the present invention. The layout, shape and number of the display, buttons and other components of a portable game machine to which such semiconductor device is applied are The configuration is not limited to that shown in Fig. 23(F). The present invention is not limited to the configuration shown in F).

[0380] In the above, we have given examples of game consoles such as stationary game consoles and portable game consoles. In addition to the above, the semiconductor device of one embodiment of the present invention can also be used in arcade game machines (arcade game machines) ) can also be applied to

[0381] <Television equipment> The semiconductor device of one embodiment of the present invention can be applied to a television set. The television device shown in Figure 9G) comprises a housing 9000, a display unit 9001, a speaker 9003, an operation panel 9004, and a display panel 9005. It has an operation key 9005 (including a power switch or an operation switch), a connection terminal 9006, etc. The television device has a large screen, for example, 50 inches or more, or 100 inches or more. A display unit 9001 can be incorporated.

[0382] <Mobile object> The semiconductor device of one embodiment of the present invention can be applied to the vicinity of a driver's seat in an automobile, which is a moving object. Cut.

[0383] For example, FIG. 23(H) is a diagram showing the area around the windshield inside the interior of an automobile. In FIG. 23(H), a display panel 5701 attached to the dashboard and a display panel 5 702, a display panel 5703, and a display panel 5704 attached to the pillar are also shown. are.

[0384] The display panels 5701 to 5703 display navigation information, a speedometer, It displays the time, tachometer, mileage, fuel gauge, gear status, air conditioning settings, etc. Therefore, various information can be provided. The layout can be changed as needed to suit the user's preferences, enhancing the design. The display panels 5701 to 5703 can be used as lighting devices. It is also possible that

[0385] The display panel 5704 displays an image captured by an imaging means provided on the vehicle body. This allows the driver to compensate for the blind spot (blind spot) that is blocked by the pillar. By displaying images from the provided imaging means, blind spots can be compensated for and safety can be improved. In addition, by projecting images that complement the invisible parts, it is possible to make the sense of incongruity appear more natural. The display panel 5704 can also be used as a lighting device. can.

[0386] <Electronic devices for electronic advertising> The semiconductor device of one embodiment of the present invention can be applied to a display for electronic advertising. Figure 24(A) shows an example of a wall-mountable digital signage. FIG. 24(A) shows a state in which an electronic signboard 6200 is attached to a wall 6201. This shows:

[0387] <Foldable tablet-type information terminal> The semiconductor device of one embodiment of the present invention can be applied to a tablet information terminal. 24(B) shows a tablet-type information terminal with a foldable structure. The information terminal shown in FIG. 24B includes a housing 5321a, a housing 5321b, and a display unit 5321b. 22 and an operation button 5323. In particular, the display unit 5322 is flexible. The device has a base material, and the base material allows the device to have a foldable structure.

[0388] The housing 5321a and the housing 5321b are connected by a hinge portion 5321c. The hinge portion 5321c allows the display portion 532 to be folded in half. 2 is provided on the housing 5321a, the housing 5321b, and the hinge portion 5321c.

[0389] Although not shown, in FIGS. 23(A) to 23(C), (E), 24(A), and 24(B), The electronic device shown may have a microphone and a speaker. For example, the electronic device described above can be provided with a voice input function.

[0390] Although not shown, the same as those shown in FIGS. 23(A), (B), (D), 24(A), and (B) The electronic device may have a camera.

[0391] Although not shown, the electrodes shown in FIGS. 23(A) to 23(G) and 24(A) and 24(B) The slave device has sensors (force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance) inside the housing. , light, liquid, magnetism, temperature, chemicals, sound, time, hardness, electric field, current, voltage, power, radiation (including functions to measure temperature, flow rate, humidity, gradient, vibration, odor, or infrared rays) In particular, the mobile phone shown in FIG. 23(D) may be provided with a gyro, an acceleration sensor, etc. By providing a detection device having a sensor that detects the tilt of the mobile phone, the orientation (vertical direction) of the mobile phone can be detected. The direction of the mobile phone relative to the direction of the camera is determined, and the screen display of the display unit 5502 is displayed. The display can be automatically switched depending on the orientation of the mobile phone.

[0392] Although not shown, the electrodes shown in FIGS. 23(A) to 23(G) and 24(A) and 24(B) The slave device is configured to have a device for acquiring biometric information such as fingerprints, veins, irises, or voiceprints. By applying this configuration, an electronic device having a biometric authentication function can be realized. It is possible.

[0393] In addition, flexible displays may be used as display units for the electronic devices shown in FIGS. 23(A) to 23(G) and 24(A). Specifically, the display unit may be a display unit having a track on a flexible substrate. A configuration including a transistor, a capacitance element, a display element, etc. may also be used. As a result, flat electronic devices such as those shown in FIGS. 23(A) to 23(G) and 24(A) can be used. Not only the housing with a surface, but also the curved part such as the dashboard and pillar shown in Figure 23(H) It is possible to realize an electronic device having a housing with a surface.

[0394] A flexible display device that can be applied to the display units shown in FIGS. 23(A) to 23(G) and 24(A) and 24(B) is shown. Examples of the base material that can be used include a material that is transparent to visible light, such as polyethylene terephthalate. Phthalate resin (PET), polyethylene naphthalate resin (PEN), polyether Polypropylene resin (PES), polyacrylonitrile resin, acrylic resin, polyimide resin, Polymethyl methacrylate resin, polycarbonate resin, polyamide resin, polycyclohexyl acrylate resin olefin resin, polystyrene resin, polyamide-imide resin, polypropylene resin, polyethylene Use ster resin, polyvinyl halide resin, aramid resin, epoxy resin, etc. These materials may also be mixed or laminated.

[0395] Note that this embodiment mode can be appropriately combined with other embodiment modes shown in this specification. do. [Explanation of symbols]

[0396] M1: transistor, M2: transistor, M3: transistor, CA: capacitance element, CB : Capacitor, CF: Capacitor, BIL: Wiring, RBL: Wiring, WBL: Wiring, WOL: Wiring Line, SL: Wiring, CAL: Wiring, BGL: Wiring, BGL1: Wiring, BGL2: Wiring, BG I: Insulator, FGI: Insulator, BGE: Conductor, FGE: Conductor, PE: Conductor, WE: Conductor, 11: semiconductor device, 20: control circuit, 21: control unit, 22[1]: voltage generation circuit , 22[P]: voltage generation circuit, 22[p1]: voltage generation circuit, 22[p2]: voltage generation circuit Path, 22[p3]: voltage generating circuit, 23A: circuit, 23B: circuit, 23IN: internal circuit, 25: temperature detection circuit, 25a: temperature sensor, 25b: analog-to-digital conversion circuit, 25c : voltage control circuit, 30: memory unit, 40: memory cell array, 50: peripheral circuit, 51: work bit line driver circuit, 52: bit line driver circuit, 52a: column decoder, 52b: Recharge circuit, 52c: sense amplifier, 52d: write circuit, 53: row decoder, 54: output circuit, 56: control logic circuit, 110: first storage area, 120: second storage area 2 storage areas, 121: cache, 122: cache, 123: cache, 130: Third storage area, 140: Fourth storage area, 200: Storage device, 210: Storage circuit, 220: Memory circuit, 220a: Memory circuit, 220b: Memory circuit, 221: Memory cell, 230: Memory memory circuit, 230a: memory circuit, 230b: memory circuit, 231: memory cell, 232: memory Recell, 240: memory circuit, 300: transistor, 311: substrate, 313: semiconductor region , 314a: low resistance region, 314b: low resistance region, 315: insulator, 316: conductor, 3 20: Insulator, 322: Insulator, 324: Insulator, 326: Insulator, 328: Conductor, 3 30: conductor, 350: insulator, 352: insulator, 354: insulator, 356: conductor, 3 60: Insulator, 362: Insulator, 364: Insulator, 366: Conductor, 370: Insulator, 3 72: Insulator, 374: Insulator, 376: Conductor, 380: Insulator, 382: Insulator, 3 84: Insulator, 386: Conductor, 500: Transistor, 500A: Transistor, 50 0B:Transistor, 500C:Transistor, 500D:Transistor, 500E:Transistor Transistor, 503: conductor, 503a: conductor, 503b: conductor, 505: conductor, 510: insulator, 511: insulator, 512: insulator, 514: insulator, 516: insulator, 518: conductor, 520: insulator, 522: insulator, 524: insulator, 530: oxide, 530a: oxide, 530b: oxide, 530c: oxide, 531a: region, 531b: Region, 540a: conductor, 540b: conductor, 542a: conductor, 542b: conductor, 5 43a: Region, 543b: Region, 544: Insulator, 545: Insulator, 546: Conductor, 5 46a: conductor, 546b: conductor, 547a: conductor, 547b: conductor, 548: conductor Electrical material, 550: Insulator, 552: Metal oxide, 560: Conductor, 560a: Conductor, 56 0b: conductor, 570: insulator, 571: insulator, 573: insulator, 574: insulator, 5 75: Insulator, 576a: Insulator, 576b: Insulator, 580: Insulator, 581: Insulator , 582: insulator, 586: insulator, 600: capacitive element, 610: conductor, 612: conductor body, 620: conductor, 630: insulator, 650: insulator, 5201: housing, 5202: surface Display unit, 5203: button, 5321a: housing, 5321b: housing, 5321c: hinge unit , 5322: display unit, 5323: operation button, 5401: housing, 5402: display unit, 54 03: Keyboard, 5404: Pointing device, 5501: Housing, 5502: Table display unit, 5503: microphone, 5504: speaker, 5505: operation buttons, 5701: display panel, 5702: display panel, 5703: display panel, 5704: display panel, 580 1: first housing, 5802: second housing, 5803: display unit, 5804: operation keys, 5805 : Lens, 5806: Connection part, 5901: Housing, 5902: Display part, 5903: Operation button , 5904: Operator, 5905: Band, 6200: Digital sign, 6201: Wall, 752 0: Game console, 7522: Controller, 9000: Housing, 9001: Display, 90 03: Speaker, 9005: Operation keys, 9006: Connection terminal

Claims

1. a storage device and a control circuit, the storage device has a first storage circuit that operates in a first storage hierarchy and a second storage circuit that operates in a second storage hierarchy; the first memory circuit includes a first transistor having a first gate and a second gate; the second memory circuit includes a second transistor having a first gate and a second gate; The control circuit a function of changing the first memory circuit from the first memory hierarchy to the second memory hierarchy by varying a voltage input to the second gate of the first transistor; and a function of changing the second memory circuit from the second memory hierarchy to the first memory hierarchy by varying a voltage input to a second gate of the second transistor. Semiconductor device.

2. a storage device and a control circuit, the storage device has a first storage circuit that operates in a first storage hierarchy and a second storage circuit that operates in a second storage hierarchy; the first storage tier is a tier having a faster access speed than the second storage tier, the first memory circuit includes a first transistor having a first gate and a second gate; the second memory circuit includes a second transistor having a first gate and a second gate; The control circuit a function of changing the first memory circuit from the first memory hierarchy to the second memory hierarchy by varying a voltage input to the second gate of the first transistor; and a function of changing the second memory circuit from the second memory hierarchy to the first memory hierarchy by varying a voltage input to the second gate of the second transistor. Semiconductor device.

3. In claim 1 or claim 2, the control circuit includes a temperature detection circuit; The temperature detection circuit has a function of outputting a correction voltage according to the temperature around the storage device.

Images