Battery pack

Abstract

To provide a semiconductor device reduced in power consumption.SOLUTION: A semiconductor device has a node ND1, a node ND2, a resistor, a capacitor, and a comparator circuit, and the resistor is electrically connected in series between a first terminal and one of a positive electrode and a negative electrode of a secondary battery. The resistor has a function of converting a current flowing between the first terminal and the one of the positive electrode and the negative electrode of the secondary battery into a first voltage. The first voltage is added to a voltage of the node ND2 via the capacitor. The comparator circuit has a function of comparing a voltage of the node ND1 and the voltage of the node ND2. When the voltage of the node ND2 is higher than the voltage of the node ND1, the comparison circuit outputs a signal indicating that an overcurrent has been detected.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] 1. Field of the Invention One embodiment of the present invention relates to a semiconductor device and a method for operating the semiconductor device. Another embodiment of the present invention relates to a battery control circuit, a battery protection circuit, a power storage device, and an electronic device.

[0002] Note that one embodiment of the present invention is not limited to the above technical field. The technical field of the invention disclosed in this specification relates to an object, a method, or a manufacturing method. Alternatively, one embodiment of the present invention relates to a process, a machine, a manufacture, or a composition of matter. Therefore, more specifically, examples of the technical field of one embodiment of the present invention disclosed in this specification include a display device, a light-emitting device, a power storage device, an imaging device, a storage device, a driving method thereof, or a manufacturing method thereof.

[0003] In this specification and the like, a semiconductor device generally refers to anything that can function by utilizing semiconductor characteristics. Thus, semiconductor elements and semiconductor circuits such as transistors and diodes are semiconductor devices. Furthermore, display devices, light-emitting devices, lighting devices, electro-optical devices, electronic devices, and the like may include semiconductor elements and semiconductor circuits. Thus, display devices, light-emitting devices, lighting devices, electro-optical devices, imaging devices, electronic devices, and the like may also be called semiconductor devices. [Background technology]

[0004] In recent years, various types of power storage devices, such as lithium ion secondary batteries, lithium ion capacitors, and air batteries, have been actively developed. In particular, the demand for high-output, high-energy-density lithium ion secondary batteries has rapidly expanded in conjunction with the development of the semiconductor industry, and they have become indispensable in the modern information society as a rechargeable energy source, for use in portable information terminals, such as mobile phones, smartphones, tablets, and notebook computers, game devices, portable music players, digital cameras, medical devices, next-generation clean energy automobiles, such as hybrid electric vehicles (HEVs), electric vehicles (EVs), and plug-in hybrid electric vehicles (PHEVs), and electric motorcycles.

[0005] Patent Document 1 discloses a semiconductor device that detects an overcurrent and controls the charging and discharging of a secondary battery. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2014-166071 A Summary of the Invention [Problem to be solved by the invention]

[0007] In the configuration shown in Patent Document 1, power consumption is likely to increase because a constant current source is used to detect overcurrent. Also, in the configuration shown in Patent Document 1, the detection of overcurrent is affected by the resistance value variations of the discharging transistor and the charging transistor, making it difficult to improve the detection accuracy.

[0008] An object of one embodiment of the present invention is to provide a semiconductor device or the like with reduced power consumption. Another object is to provide a semiconductor device or the like with high accuracy in detecting overcurrent. Another object is to provide a semiconductor device or the like with stable operation. Another object is to provide a semiconductor device or the like with high reliability. Another object is to provide a semiconductor device or the like with high productivity. Another object is to provide a novel semiconductor device or the like.

[0009] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that problems other than these will become apparent from the description of the specification, drawings, claims, etc., and it is possible to extract problems other than these from the description of the specification, drawings, claims, etc. [Means for solving the problem]

[0010] One embodiment of the present invention is a semiconductor device having nodes ND1 and ND2, a resistor, a capacitor, and a comparator circuit. The resistor is electrically connected in series between one of a positive electrode or a negative electrode of a secondary battery and a first terminal. The resistor has a function of converting a current flowing between one of the positive electrode or the negative electrode of the secondary battery and the first terminal into a first voltage. The first voltage is added to the voltage of node ND2 via the capacitor. The comparator circuit has a function of comparing the voltage of node ND1 with the voltage of node ND2. When the voltage of node ND2 is higher than the voltage of node ND1, the comparator circuit outputs a signal notifying that an overcurrent has been detected.

[0011] Another embodiment of the present invention is a semiconductor device including first to fourth transistors and a comparator, in which one of a source or a drain of the first transistor is electrically connected to a non-inverting input terminal of the comparator, one of a source or a drain of the second transistor is electrically connected to an inverting input terminal of the comparator, one of a source or a drain of the third transistor is electrically connected to one of a source or a drain of the fourth transistor, and a resistor is provided between the other of the source or the drain of the third transistor and the other of the source or the drain of the fourth transistor.

[0012] The resistance value of the resistor may be 1 mΩ or more and 10 Ω or less. A first capacitance may be provided at one of the source or drain of the first transistor. The capacitance value of the first capacitance may be 0.01 fF or more and 100 pF or less. A second capacitance may be provided between one of the source or drain of the second transistor and one of the source or drain of the third transistor. The capacitance value of the second capacitance may be 0.01 fF or more and 100 pF or less.

[0013] The first and second transistors preferably include an oxide semiconductor in a semiconductor layer, and the third and fourth transistors preferably include an oxide semiconductor in a semiconductor layer.

[0014] At least one of the first to fourth transistors may be a multi-gate transistor.

[0015] The potential supplied to the other of the source or the drain of the first transistor is preferably lower than the potential supplied to the other of the source or the drain of the second transistor.

[0016] Another embodiment of the present invention is a semiconductor device having a first transistor, a second transistor, and a comparator, in which one of a source or a drain of the first transistor is electrically connected to a non-inverting input terminal of the comparator, one of the source or the drain of the first transistor has a first capacitance, one of the source or the drain of the second transistor is electrically connected to an inverting input terminal of the comparator, and a second capacitance is provided between one of the source or the drain of the second transistor and a resistor.

[0017] Another embodiment of the present invention is a battery pack including a semiconductor device provided over a flexible substrate, an insulating sheet, and a secondary battery.

[0018] The battery pack may include a first diode, a second diode, a second resistor, and a third capacitor. The cathode of the first diode is electrically connected to the positive electrode of the secondary battery, the anode of the first diode is electrically connected to the cathode of the second diode, and the anode of the second diode is electrically connected to the negative electrode of the secondary battery. The second resistor is provided between the anode of the first diode and the output terminal of the comparator, and the third capacitor is connected in parallel with the second diode.

[0019] One or both of the first diode and the second diode may be formed of a transistor. Effect of the Invention

[0020] According to one embodiment of the present invention, a semiconductor device or the like with reduced power consumption can be provided. Alternatively, a semiconductor device or the like with high accuracy in detecting an overcurrent can be provided. Alternatively, a semiconductor device or the like with stable operation can be provided. Alternatively, a semiconductor device or the like with high reliability can be provided. Alternatively, a semiconductor device or the like with high productivity can be provided. Alternatively, a novel semiconductor device or the like can be provided.

[0021] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not need to have all of these effects. Note that effects other than these will become apparent from the description in the specification, drawings, claims, etc., and it is possible to extract effects other than these from the description in the specification, drawings, claims, etc. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a diagram illustrating an example of a configuration of a semiconductor device. [Diagram 2] 2A and 2B are diagrams illustrating an example of the operation of the semiconductor device. [Diagram 3] 3A and 3B are diagrams illustrating an example of the operation of the semiconductor device. [Figure 4] 4A and 4B are diagrams illustrating a configuration example of a semiconductor device. [Diagram 5] 5A to 5D are diagrams showing circuit symbols for transistors. [Figure 6] FIG. 6 is a diagram illustrating a configuration example of a semiconductor device. [Figure 7] 7A and 7B are diagrams illustrating an example of the operation of the semiconductor device. [Figure 8] 8A and 8B are diagrams illustrating an example of the operation of the semiconductor device. [Figure 9] FIG. 9 is a diagram illustrating a configuration example of a semiconductor device. [Figure 10] 10A and 10B are diagrams illustrating an example of the operation of the semiconductor device. [Figure 11] 11A and 11B are diagrams illustrating an example of the operation of the semiconductor device. [Figure 12] FIG. 12 is a diagram illustrating a configuration example of a semiconductor device. [Figure 13] 13A and 13B are diagrams illustrating an example of the operation of the semiconductor device. [Figure 14] 14A and 14B are diagrams illustrating an example of the operation of the semiconductor device. [Figure 15] FIG. 15 is a diagram illustrating a configuration example of a semiconductor device. [Figure 16] FIG. 16 is a diagram illustrating a configuration example of a semiconductor device. [Figure 17] FIG. 17 is a diagram illustrating a configuration example of a semiconductor device. [Figure 18] 18A to 18D are diagrams showing equivalent circuits of the protection device. [Figure 19] 19A and 19B are diagrams showing an equivalent circuit of a protection device. [Figure 20] 20A and 20B are diagrams showing an equivalent circuit of a protection device. [Figure 21] 21A to 21C are diagrams showing equivalent circuits of a protection device. [Figure 22] FIG. 22 is a diagram illustrating a configuration example of a semiconductor device. [Diagram 23] 23A to 23C are diagrams showing equivalent circuits of a protection device. [Figure 24] FIG. 24 is a diagram illustrating a configuration example of a semiconductor device. [Diagram 25] FIG. 25 is a diagram showing an equivalent circuit of a protection device. [Figure 26] FIG. 26 is a diagram illustrating a configuration example of a semiconductor device. [Figure 27] FIG. 27 is a diagram illustrating a configuration example of a semiconductor device. [Figure 28] FIG. 28 is a diagram showing an equivalent circuit of a protection device. [Figure 29] FIG. 29 is a diagram illustrating a configuration example of a semiconductor device. [Diagram 30] FIG. 30 is a diagram illustrating a configuration example of a semiconductor device. [Diagram 31] 31A to 31C are diagrams showing examples of the structure of a transistor. [Diagram 32] 32A to 32C are diagrams showing examples of the structure of a transistor. [Diagram 33] 33A to 33C are diagrams showing examples of the structure of a transistor. [Diagram 34] 34A to 34C are diagrams showing examples of the structure of a secondary battery. [Diagram 35]35A to 35C are diagrams showing structural examples of a secondary battery. [Diagram 36] 36A and 36B are diagrams showing examples of the structure of a wound body and a secondary battery. [Figure 37] FIG. 37 is a diagram illustrating an example of an electronic device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be easily understood by those skilled in the art that the form and details of the present invention can be modified in various ways without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiments shown below. In the configuration of the invention described below, the same parts or parts having similar functions are denoted by the same reference numerals in different drawings, and repeated explanations thereof will be omitted.

[0024] In addition, the position, size, range, etc. of each component shown in the drawings, etc. may not represent the actual position, size, range, etc. in order to facilitate understanding of the invention. Therefore, the disclosed invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings, etc. For example, in an actual manufacturing process, a resist mask, etc. may be unintentionally eroded by a process such as etching, but this may not be reflected in the drawings in order to facilitate understanding.

[0025] In addition, in top views (also called "plan views"), perspective views, and the like, illustration of some components may be omitted in order to make the drawings easier to understand.

[0026] In addition, the terms "electrode" and "wiring" used in this specification and the like do not limit the functionality of these components. For example, an "electrode" may be used as part of a "wiring", and vice versa. Furthermore, the terms "electrode" and "wiring" include cases where multiple "electrodes" or "wirings" are formed integrally.

[0027] In addition, in this specification and the like, a "terminal" in an electric circuit refers to a portion where a current is input or output, a voltage is input or output, or a signal is received or transmitted. Therefore, a part of a wiring or an electrode may function as a terminal.

[0028] In this specification, the terms "above" and "below" do not limit the positional relationship of components to being directly above or below and in direct contact. For example, the expression "electrode B on insulating layer A" does not require that electrode B be formed in direct contact with insulating layer A, and does not exclude the inclusion of other components between insulating layer A and electrode B.

[0029] In addition, the functions of the source and drain are interchangeable depending on the operating conditions, such as when transistors of different polarities are used or when the direction of current changes during circuit operation, so it is difficult to determine which is the source and which is the drain. For this reason, in this specification, the terms source and drain can be used interchangeably.

[0030] In addition, in this specification, "electrically connected" includes a direct connection and a connection via "something having some electrical action." Here, the "something having some electrical action" is not particularly limited as long as it allows the transmission and reception of electrical signals between the connected objects. Therefore, even when it is expressed as "electrically connected," in the actual circuit, there may be no physical connection and only wiring extending therethrough.

[0031] In addition, in this specification, "parallel" refers to, for example, a state in which two straight lines are arranged at an angle of -10° or more and 10° or less. Therefore, it also includes the case of -5° or more and 5° or less. Furthermore, "perpendicular" and "orthogonal" refer to, for example, a state in which two straight lines are arranged at an angle of 80° or more and 100° or less. Therefore, it also includes the case of 85° or more and 95° or less.

[0032] In this specification and elsewhere, when referring to counting values ​​and measurement values, terms such as "same," "equal," "uniform," etc. are used, they are intended to include an error of plus or minus 20% unless otherwise expressly stated.

[0033] In addition, in this specification, when an etching process is performed after forming a resist mask, the resist mask is removed after the etching process is completed, unless otherwise specified.

[0034] Furthermore, voltage often refers to the potential difference between a certain potential and a reference potential (for example, a ground potential or a source potential). Therefore, voltage and potential can often be interchanged. In this specification and the like, unless otherwise specified, voltage and potential can be interchanged.

[0035] Even when written as "semiconductor", for example, if the conductivity is sufficiently low, it has the characteristics of an "insulator". Therefore, it is also possible to use "semiconductor" instead of "insulator". In this case, the boundary between "semiconductor" and "insulator" is ambiguous, and it is difficult to strictly distinguish between the two. Therefore, "semiconductor" and "insulator" described in this specification may be read as interchangeable.

[0036] Furthermore, even when written as "semiconductor", if the conductivity is sufficiently high, it has the characteristics of a "conductor". Therefore, it is also possible to use "semiconductor" in place of "conductor". In this case, the boundary between "semiconductor" and "conductor" is ambiguous, and it is difficult to strictly distinguish between the two. Therefore, "semiconductor" and "conductor" described in this specification may be interchangeable.

[0037] In addition, ordinal numbers such as "first" and "second" in this specification are used to avoid confusion of components, and do not indicate any order or ranking, such as the order of processes or stacking. Even if a term does not have an ordinal number in this specification, an ordinal number may be added in the claims to avoid confusion of components. Even if a term has an ordinal number in this specification, a different ordinal number may be added in the claims. Even if a term has an ordinal number in this specification, the ordinal number may be omitted in the claims.

[0038] In this specification, the "on state" of a transistor refers to a state in which the source and drain of the transistor can be regarded as being electrically short-circuited (also referred to as a "conductive state"). The "off state" of a transistor refers to a state in which the source and drain of the transistor can be regarded as being electrically disconnected (also referred to as a "non-conductive state").

[0039] In this specification, the term "on-state current" may refer to a current that flows between a source and a drain when a transistor is on, and the term "off-state current" may refer to a current that flows between a source and a drain when a transistor is off.

[0040] In this specification and the like, high power supply potential VDD (hereinafter simply referred to as "VDD" or "H potential") refers to a power supply potential that is higher than the low power supply potential VSS. Also, low power supply potential VSS (hereinafter simply referred to as "VSS" or "L potential") refers to a power supply potential that is lower than the high power supply potential VDD. Also, the ground potential can be used as VDD or VSS. For example, when VDD is the ground potential, VSS is a potential lower than the ground potential, and when VSS is the ground potential, VDD is a potential higher than the ground potential.

[0041] In this specification and the like, a gate refers to a gate electrode and a part or the whole of a gate wiring. A gate wiring refers to a wiring for electrically connecting a gate electrode of at least one transistor to another electrode or another wiring.

[0042] In this specification and the like, the source refers to a source region, a source electrode, and a part or all of a source wiring. The source region refers to a region of a semiconductor layer having a resistivity equal to or lower than a certain value. The source electrode refers to a conductive layer connected to the source region. The source wiring refers to a wiring for electrically connecting the source electrode of at least one transistor to another electrode or another wiring.

[0043] In this specification and the like, the drain refers to a part or all of the drain region, the drain electrode, and the drain wiring. The drain region refers to a region of the semiconductor layer whose resistivity is equal to or lower than a certain value. The drain electrode refers to a conductive layer that is connected to the drain region. The drain wiring refers to a wiring for electrically connecting the drain electrode of at least one transistor to another electrode or another wiring.

[0044] (Embodiment 1) A semiconductor device according to one embodiment of the present invention will be described with reference to drawings.

[0045] <Configuration Example of Semiconductor Device 200A> 1 shows an example of the configuration of a semiconductor device 200A. The semiconductor device 200A includes terminals 201 to 204, a semiconductor device 100C, a control circuit 210, a potential generating circuit 220, a resistor 211, a capacitor 212, a transistor 213, a transistor 214, a diode 215, and a diode 216.

[0046] The semiconductor device 100C has a terminal R, a terminal RFN, a terminal SH, a terminal SHB, and a terminal OUT. The semiconductor device 100C also has a comparator 101, transistors 111 to 114, a capacitor 102, a capacitor 103, and a resistor 121.

[0047] The control circuit 210 has terminals 221 to 225. One terminal of the resistor 211 is electrically connected to the terminal 201 and the terminal 203, and the other terminal is electrically connected to the terminal 221. One terminal of the capacitor 212 is electrically connected to the terminal 221, and the other terminal is electrically connected to the terminal 222 and the terminal 204.

[0048] One of the source and the drain of the transistor 213 is electrically connected to the terminal 222 and the terminal 204, and the gate is electrically connected to the terminal 223. The anode of the diode 215 is electrically connected to one of the source and the drain of the transistor 213. The cathode of the diode 215 is electrically connected to the other of the source and the drain of the transistor 213.

[0049] One of the source or the drain of the transistor 214 is electrically connected to the other of the source or the drain of the transistor 213, and the other of the source or the drain of the transistor 214 is electrically connected to one terminal of the resistor 121. The gate of the transistor 214 is electrically connected to a terminal 224. The cathode of the diode 216 is electrically connected to the other of the source or the drain of the transistor 214. The anode of the diode 216 is electrically connected to the other of the source or the drain of the transistor 214. The other terminal of the resistor 121 is electrically connected to the terminal 202.

[0050] The potential generating circuit 220 generates a potential V R and the function of supplying potential V RFN The control circuit 210 has a function of controlling the operation of the potential generating circuit 220.

[0051] The comparator 101 has a non-inverting input terminal, an inverting input terminal, and an output terminal. When the potential of the non-inverting input terminal is higher than the potential of the inverting input terminal, the comparator 101 outputs a potential V OUTWhen the potential of the non-inverting input terminal is lower than the potential of the inverting input terminal, the comparator 101 outputs a potential V OUT The comparator 101 has a function of outputting an L potential as a reference potential. The comparator 101 functions as a comparison circuit. An output terminal of the comparator 101 is electrically connected to a terminal OUT. In addition, the terminal OUT is electrically connected to a terminal 225 of the control circuit 210 via a wiring 122.

[0052] One of the source and the drain of the transistor 111 is electrically connected to the terminal R, and the other of the source and the drain of the transistor 111 is electrically connected to the non-inverting input terminal of the comparator 101. The gate of the transistor 111 is electrically connected to the terminal SH.

[0053] One electrode of the capacitor 102 is electrically connected to the non-inverting input terminal of the comparator 101. The other electrode of the capacitor 102 is supplied with a reference potential or a fixed potential.

[0054] A node where the other of the source and the drain of the transistor 111, the non-inverting input terminal of the comparator 101, and one electrode of the capacitor 102 are electrically connected is called a node ND1.

[0055] One of the source and the drain of the transistor 112 is electrically connected to the terminal RFN, and the other of the source and the drain of the transistor 112 is electrically connected to the inverting input terminal of the comparator 101. The gate of the transistor 112 is electrically connected to the terminal SH.

[0056] One electrode of the capacitor 103 is electrically connected to the inverting input terminal of the comparator 101 .

[0057] A node where the other of the source and the drain of the transistor 112, the inverting input terminal of the comparator 101, and one electrode of the capacitor 103 are electrically connected is referred to as a node ND2.

[0058] One of the source and the drain of the transistor 113 is electrically connected to one terminal of the resistor 121, and the other of the source and the drain of the transistor 113 is electrically connected to the other electrode of the capacitor 103. The gate of the transistor 113 is electrically connected to the terminal SH.

[0059] One of the source and the drain of the transistor 114 is electrically connected to the other terminal of the resistor 121, and the other of the source and the drain of the transistor 114 is electrically connected to the other electrode of the capacitor 103. The gate of the transistor 114 is electrically connected to the terminal SHB.

[0060] The inverted potential of terminal SH is supplied to terminal SHB. For example, when an H potential is supplied to terminal SH, an L potential is supplied to terminal SHB. Similarly, when an L potential is supplied to terminal SH, an H potential is supplied to terminal SHB. However, during certain periods of circuit operation, the potentials of terminals SHB and SH may be the same.

[0061] A node where the other of the source or drain of the transistor 113, the other of the source or drain of the transistor 114, and the other electrode of the capacitor 103 are electrically connected is referred to as a node ND3.

[0062] A node where the other of the source or drain of the transistor 214, one of the source or drain of the transistor 113, and one terminal of the resistor 121 are electrically connected is referred to as a node NDA. A node where the other of the source or drain of the transistor 114, the other terminal of the resistor 121, and the terminal 202 are electrically connected is referred to as a node NDB.

[0063] Moreover, the positive electrode of the secondary battery 300 is electrically connected to the terminal 203 , and the negative electrode is electrically connected to the terminal 204 .

[0064] It is preferable that the transistors 111 to 114 include transistors using an oxide semiconductor, which is a type of metal oxide, for a semiconductor layer in which a channel is formed (also referred to as "OS transistors"). In particular, it is preferable that the transistors 111 to 112 include OS transistors.

[0065] OS transistors can reduce their off-state current to as low as 1×10 per 1 μm of channel width at room temperature. -20 Less than A, preferably 1×10 -22 A, more preferably less than 1×10 -24 It can be less than A.

[0066] Furthermore, the off-state current of an OS transistor hardly increases even in a high-temperature environment. Specifically, the off-state current hardly increases even in an environmental temperature range of room temperature to 200° C. By using an OS transistor as a transistor constituting a semiconductor device, a semiconductor device with stable operation and high reliability even in a high-temperature environment can be realized.

[0067] By using an OS transistor as the transistor 111, the capacitance 102 can be made smaller. Alternatively, the capacitance 102 can be omitted and a parasitic capacitance of a transistor or the like can be used instead of the capacitance 102. As a result, the occupation area of ​​the semiconductor device 100C can be made smaller. Therefore, the occupation area of ​​the semiconductor device 200A can be made smaller.

[0068] Generally, a capacitor has a configuration in which two electrodes face each other via a dielectric. The capacitance value is proportional to the overlapping area of ​​the facing electrodes and the relative dielectric constant of the dielectric, and inversely proportional to the distance between the two electrodes. When providing the capacitor 102, if the capacitance value is too large, the area occupied by the semiconductor device 200A tends to become large, which is not preferable. In addition, if the capacitance value of the capacitor 102 is large, power consumption due to charging and discharging of the capacitor 102 increases.

[0069] When the capacitor 102 is provided, the capacitance value of the capacitor 102 is preferably 0.01 fF or more and 100 pF or less, more preferably 0.05 fF or more and 10 pF or less, and further preferably 0.1 fF or more and 1 pF or less.

[0070] Similarly, the capacitance 103 can be reduced by using an OS transistor as the transistor 112. Alternatively, the capacitor 103 can be omitted and a parasitic capacitance of a transistor or the like can be used instead of the capacitor 103.

[0071] When the capacitance 103 is provided, if the capacitance value is too large, the area occupied by the semiconductor device 200A tends to become large, which is undesirable. Also, if the capacitance value of the capacitor 103 is large, the power consumption due to charging and discharging of the capacitor 103 increases.

[0072] When the capacitor 103 is provided, the capacitance value of the capacitor 103 is preferably 0.01 fF or more and 100 pF or less, more preferably 0.05 fF or more and 10 pF or less, and further preferably 0.1 fF or more and 1 pF or less.

[0073] Furthermore, the off-state current of the OS transistor is unlikely to increase even in a high-temperature environment (for example, an environment of 50° C. to 150° C.) Therefore, the potential (charge) supplied to the node ND1 and the node ND2 can be held for a long period of time even in a high-temperature environment.

[0074] In this manner, the transistor 111 and the capacitor 102 form a memory element 151. The transistor 112 and the capacitor 103 form a memory element 152. A memory element using an OS transistor as the transistor forming the memory element may be called an "OS memory".

[0075] In addition, an OS transistor has a high withstand voltage between the source and the drain. Therefore, an OS transistor can be used as the transistor 213 and the transistor 214. By using an OS transistor, a semiconductor device or the like with high reliability can be provided.

[0076] Note that a charge control circuit, a discharge control circuit, an overcurrent detection circuit, an abnormality detection circuit, a secondary battery control system, or the like using an OS transistor may be referred to as a battery operating system (BTOS) or a battery oxide semiconductor.

[0077] <Operation Example of Semiconductor Device 200A> The control circuit 210 has a function of selecting the on state or off state of the transistor 213. The control circuit 210 also has a function of selecting the on state or off state of the transistor 214.

[0078] The secondary battery 300 is charged by connecting the positive electrode of an external power supply for charging to terminal 201 and the negative electrode of the same power supply to terminal 202. The charging operation is performed with transistor 214 in the on state. The secondary battery 300 can be charged by passing a current supplied from the external power supply from terminal 201 to terminal 202 via terminals 203 and 204.

[0079] The secondary battery 300 is discharged by connecting a load between the terminals 201 and 202. The discharging operation is performed by turning on the transistor 213. During the discharging operation, a current flows from the terminal 202 to the terminal 201 via the terminals 204 and 203. During the charging operation and the discharging operation, the direction of the current flowing through the resistor 121 is reversed.

[0080] The control circuit 210 also has a function of detecting the state of the secondary battery 300, such as the charging voltage and temperature of the secondary battery 300. The control circuit 210 also has a function of detecting the state of the secondary battery 300 and controlling the execution or stop of the charging operation and discharging operation.

[0081] Specifically, the control circuit 210 can stop the discharging operation of the secondary battery 300 by turning off the transistor 213. Also, the control circuit 210 can stop the charging operation of the secondary battery 300 by turning off the transistor 214. By turning off either the transistor 213 or the transistor 214, either the charging operation or the discharging operation of the secondary battery 300 can be stopped.

[0082] The semiconductor device 100C has a function of detecting a current (also called an "overcurrent") exceeding a prescribed level in the resistor 121 during charging. Specifically, the semiconductor device 100C outputs an H potential when it detects an overcurrent during charging. OUT ) is supplied to a terminal 225 of the control circuit 210 via a wiring 122. The semiconductor device 100C functions as an overcurrent detection circuit during a charging operation.

[0083] When an H potential is supplied to the terminal 225, the control circuit 210 of the semiconductor device 200A turns off the transistor 214 and stops the charging operation. By not charging due to an overcurrent, it is possible to prevent rapid deterioration of the characteristics of the secondary battery 300. This makes it possible to extend the battery life of the secondary battery 300. Also, it is possible to improve the reliability of the secondary battery 300. Also, it is possible to improve the safety of the secondary battery 300.

[0084] [Operation Example of Semiconductor Device 100C] The semiconductor device 100C functions as an overcurrent detection circuit. An operation example of the semiconductor device 100C will be described with reference to Figures 2 and 3. Figures 2 and 3 are diagrams showing the operating state of the semiconductor device 100C.

[0085] In addition, in drawings and the like, to make the potential of wiring and electrodes easier to understand, "H" indicating H potential or "L" indicating L potential may be written next to the wiring and electrode. Wiring and electrodes where a potential change has occurred may be written with "H" or "L" enclosed in a box. When a transistor is in the off state, an "x" symbol may be written over the transistor.

[0086] As mentioned above, terminal R has a potential of V R is supplied, and the terminal RFN is at potential V RFN In this embodiment, the potential V R is set to 1.1V, and the potential V RFN is set to 1.25V.

[0087] First, before charging starts, an H potential is supplied to the terminal SH, and an L potential is supplied to the terminal SHB (see FIG. 2A). Then, the transistor 111 is turned on, and the potential of the node ND1 becomes 1.1 V. Also, the transistor 112 is turned on, and the potential of the node ND2 becomes 1.25 V. Therefore, the potential V OUT becomes the L potential.

[0088] At this time, the potentials of the nodes NDA and NDB are 0 V (reference potential) because no current flows through the resistor 121. When the H potential is supplied to the terminal SH, the transistor 113 is turned on, and the potential of the node ND3 becomes 0 V.

[0089] Next, an L potential is supplied to the terminal SH, and an H potential is supplied to the terminal SHB (see FIG. 2B). Then, the transistor 111 is turned off, and the potential of the node ND1 is held. Similarly, the transistor 112 is turned off, and the potential of the node ND2 is held. In addition, the transistor 113 is also turned off.

[0090] Next, the charging operation starts. When charging starts, a current I C (See Figure 3A.) Current I Cflows from node NDA to node NDB, so when charging starts, the potential of node NDB becomes lower than 0 V. Therefore, the potential of node ND3 also becomes lower than 0 V.

[0091] The resistance value of the resistor 121 is preferably 1 mΩ or more and 10 Ω or less, more preferably 5 mΩ or more and 5 Ω or less, and further preferably 10 mΩ or more and 1 Ω or less. By changing the resistance value of the resistor 121, the value of the overcurrent detected by the semiconductor device 100C can be changed. Also, a part of the wiring may be made to function as the resistor 121. In other words, the wiring resistance may be used as the resistor 121.

[0092] Current value I th Resistance value R of resistor 121 for detecting (A) or more as an overcurrent D (Ω) can be calculated using Equation 1.

[0093]

number

[0094] For example, when the value of the current Ith is set to 1 mA, the potential V RFN is 1.25V, and the potential V R Since the resistance is 1.1V, the resistance value R D It can be seen that it is necessary to set it to 150 Ω.

[0095] FIG. 3A shows the resistance R D When the resistance is 150Ω, the current I C 1 shows a state in which 0.8 mA flows as a current. In this case, the potential of the node NDB becomes −0.12 V. Therefore, the potential of the node ND3 also becomes −0.12 V. Furthermore, the nodes ND3 and ND2 are capacitively coupled via the capacitor 103. Therefore, the potential of the node ND2 becomes 1.13 V. The potential of the node ND2 remains higher than the potential of the node ND1. Therefore, the potential V OUT remains at L potential.

[0096] FIG. 3B shows the resistance R DWhen the resistance is 150Ω, the current I C This shows the state when 1.1 mA flows as a current. In this case, the potential of the node NDB becomes −0.165 V. Therefore, the potential of the node ND3 also becomes −0.165 V. For the same reason as above, the potential of the node ND2 becomes 1.085 V. Then, the potential of the node ND2 becomes smaller than the potential of the node ND1, and the potential V OUT becomes H potential.

[0097] In this way, it is possible to detect an overcurrent during a charging operation. The semiconductor device 100C according to one embodiment of the present invention is configured to detect an overcurrent using the terminal 202, the transistor 213, and the resistor 121 connected in series with the transistor 214. Therefore, it is possible to detect an overcurrent with high accuracy without being affected by variations in the resistance values ​​of the transistors 213 and 214.

[0098] The resistor 121 is not limited to a fixed resistor. As shown in FIG. 4A, the resistor 121 may be a variable resistor. By making the resistor 121 a variable resistor, the current value I th For example, the current value I can be changed according to the surface temperature of the secondary battery 300. th can be changed to an optimal value.

[0099] Further, the transistors 111 to 114, the transistor 213, and the transistor 214 function as switches. The switches are elements that have a function of switching between a conductive state (ON) and a non-conductive state (OFF) between terminals and control whether a current flows or does not flow. The source of the transistor corresponds to one end of the switch, and the drain of the transistor corresponds to the other end of the switch. Therefore, for example, as shown in FIG. 4B, the transistors 111 to 114 included in the semiconductor device 100C can be replaced with switches 111s to 114s.

[0100] Each of the transistors 111 to 114, the transistor 213, and the transistor 214 may be a double-gate transistor. An example of a circuit symbol of a double-gate transistor 150A is shown in FIG 5A.

[0101] The transistor 150A has a configuration in which a transistor Tr1 and a transistor Tr2 are connected in series. Fig. 5A shows a state in which one of the source or drain of the transistor Tr1 is electrically connected to a terminal S, the other of the source or drain of the transistor Tr1 is electrically connected to one of the source or drain of the transistor Tr2, and the other of the source or drain of the transistor Tr2 is electrically connected to a terminal D. Fig. 5A also shows a state in which the gates of the transistor Tr1 and the transistor Tr2 are electrically connected and also electrically connected to a terminal G.

[0102] 5A has a function of switching the state between terminals S and D into a conductive state or a non-conductive state by changing the potential of terminal G. Thus, the transistor 150A, which is a double-gate transistor, functions as one transistor with transistors Tr1 and Tr2 built in. That is, in FIG. 5A, one of the source or drain of the transistor 150A is electrically connected to the terminal S, the other of the source or drain is electrically connected to the terminal D, and the gate is electrically connected to the terminal G.

[0103] Each of the transistors 111 to 114, the transistor 213, and the transistor 214 may be a triple-gate transistor. FIG 5B shows an example of a circuit symbol of a triple-gate transistor 150B.

[0104] The transistor 150B has a configuration in which a transistor Tr1, a transistor Tr2, and a transistor Tr3 are connected in series. In FIG. 5B, one of the source or drain of the transistor Tr1 is electrically connected to a terminal S, the other of the source or drain of the transistor Tr1 is electrically connected to one of the source or drain of the transistor Tr2, the other of the source or drain of the transistor Tr2 is electrically connected to one of the source or drain of the transistor Tr3, and the other of the source or drain of the transistor Tr3 is electrically connected to a terminal D. In addition, in FIG. 5B, the gates of the transistors Tr1, Tr2, and Tr3 are electrically connected to a terminal G.

[0105] 5B has a function of switching the state between the terminal S and the terminal D between conductive and non-conductive states by changing the potential of the terminal G. Thus, the triple-gate transistor 150B, which includes the transistors Tr1, Tr2, and Tr3, functions as one transistor. That is, in FIG. 5B, one of the source or the drain of the transistor 150B is electrically connected to the terminal S, the other of the source or the drain is electrically connected to the terminal D, and the gate is electrically connected to the terminal G.

[0106] A transistor having multiple gates that are electrically connected, such as the transistor 150A and the transistor 150B, may be referred to as a "multi-gate transistor" or a "multi-gate transistor".

[0107] Each of the transistors 111 to 114, the transistor 213, and the transistor 214 may have a back gate. Fig. 5C shows an example of a circuit symbol of a transistor 150C having a back gate. Fig. 5D shows an example of a circuit symbol of a transistor 150D having a back gate.

[0108] The transistor 150C has a structure in which the gate and the backgate are electrically connected. The transistor 150D has a structure in which the backgate is electrically connected to the terminal BG. The backgate is disposed so as to sandwich a channel formation region of the semiconductor layer between the gate and the backgate. The backgate can function in the same manner as the gate.

[0109] The on-state current of a transistor can be increased by electrically connecting the gate and the back gate, and the threshold voltage of the transistor can be changed by independently changing the potential of the back gate.

[0110] <Modification> 6 shows a configuration example of a semiconductor device 200Aa, which is a modification of the semiconductor device 200A. In this embodiment, in order to reduce repetition of explanation, differences from the semiconductor device 200A will be mainly described. The semiconductor device 200Aa differs from the semiconductor device 200A in that it has a semiconductor device 100Ca instead of the semiconductor device 100C.

[0111] The semiconductor device 100Ca has a configuration in which the transistor 113, the transistor 114, and the terminal SHB are removed from the semiconductor device 100C. In the semiconductor device 100Ca, the other electrode of the capacitance 103 is electrically connected to the other terminal of the resistor 121. Therefore, in the semiconductor device 200Aa, the node at which the other electrode of the capacitance 103 and the other terminal of the resistor 121 are electrically connected is called a node NDB. Also, in the semiconductor device 200Aa, the node at which the other of the source or drain of the transistor 214 and one terminal of the resistor 121 are electrically connected is called a node NDA.

[0112] The semiconductor device 100Ca has fewer components than the semiconductor device 100C, and therefore occupies a smaller area. Furthermore, the semiconductor device 100Ca does not have the terminal SHB, and therefore the terminal 227 can be omitted from the control circuit 210 of the semiconductor device 200Aa.

[0113] [Operation Example of Semiconductor Device 100Ca] The semiconductor device 100Ca functions as an overcurrent detection circuit, similar to the semiconductor device 100C. An operation example of the semiconductor device 100Ca will be described with reference to Figures 7 and 8. Figures 7 and 8 are diagrams showing the operating states of the semiconductor device 100Ca.

[0114] First, before the start of charging, an H potential is supplied to the terminal SH (see FIG. 7A). Then, the transistor 111 is turned on, and the potential of the node ND1 becomes 1.1 V. Also, the transistor 112 is turned on, and the potential of the node ND2 becomes 1.25 V. Therefore, the potential V OUT becomes the L potential.

[0115] At this time, since no current flows through the resistor 121, the potential of the node NDB is 0V (reference potential).

[0116] Next, an L potential is supplied to the terminal SH (see FIG. 7B). Then, the transistor 111 is turned off, and the potential of the node ND1 is held. Similarly, the transistor 112 is turned off, and the potential of the node ND2 is held.

[0117] Next, the charging operation starts. When charging starts, a current I C (See Figure 8A.) Current I C flows from node NDA to node NDB, so that when charging starts, the potential of node NDB becomes lower than 0 V. D When the resistance is 150Ω, the current I C In this case, the potential of the node NDB becomes −0.12 V. Furthermore, the node NDB and the node ND2 are capacitively coupled via the capacitor 103. Therefore, the potential of the node ND2 becomes 1.13 V. The potential of the node ND2 remains higher than the potential of the node ND1. Therefore, the potential V OUT remains at L potential.

[0118] FIG. 8B shows the resistance R DWhen the resistance is 150Ω, the current I C In this case, the potential of the node NDB becomes -0.165V. For the same reason as above, the potential of the node ND2 becomes 1.085V. Then, the potential of the node ND2 becomes smaller than the potential of the node ND1, and the potential V OUT becomes H potential.

[0119] In this manner, an overcurrent during a charging operation can be detected.The semiconductor device 200Aa according to one embodiment of the present invention has fewer components than the semiconductor device 200A, and therefore can occupy a smaller area.

[0120] Note that the semiconductor device according to one embodiment of the present invention should not be interpreted as being limited to the circuit diagrams shown in this embodiment. The semiconductor device according to one embodiment of the present invention may have a circuit configuration similar to that shown in this embodiment.

[0121] This embodiment mode can be implemented in appropriate combination with structures described in other embodiment modes.

[0122] (Embodiment 2) In this embodiment, another structural example of a semiconductor device according to one embodiment of the present invention will be described with reference to drawings.

[0123] <Configuration Example of Semiconductor Device 200B> 9 shows a configuration example of the semiconductor device 200B. The semiconductor device 200B is a modified example of the semiconductor device 200A. Therefore, in order to reduce repetition of explanation, the present embodiment will mainly describe the differences from the semiconductor device 200A.

[0124] The semiconductor device 200B is different from the semiconductor device 200A in that it has a semiconductor device 100D instead of the semiconductor device 100C. The semiconductor device 100D has a terminal R, a terminal RFN, a terminal SH, a terminal SHB, and a terminal OUT, similar to the semiconductor device 100C. The semiconductor device 100D also has a comparator 101, transistors 111 to 114, a capacitor 102, a capacitor 103, and a resistor 121.

[0125] In the semiconductor device 100D, one of the source and the drain of the transistor 111 is electrically connected to the terminal RFN, and the other of the source and the drain of the transistor 111 is electrically connected to the inverting input terminal of the comparator 101. The gate of the transistor 111 is electrically connected to the terminal SH.

[0126] One electrode of the capacitor 102 is electrically connected to the inverting input terminal of the comparator 101. The other electrode of the capacitor 102 is supplied with a reference potential or a fixed potential.

[0127] A node where the other of the source and the drain of the transistor 111, the inverting input terminal of the comparator 101, and one electrode of the capacitor 102 are electrically connected is called a node ND1.

[0128] One of the source and the drain of the transistor 112 is electrically connected to the terminal R, and the other of the source and the drain of the transistor 112 is electrically connected to the non-inverting input terminal of the comparator 101. The gate of the transistor 112 is electrically connected to the terminal SH.

[0129] One electrode of the capacitor 103 is electrically connected to the non-inverting input terminal of the comparator 101 .

[0130] A node where the other of the source and the drain of the transistor 112, the non-inverting input terminal of the comparator 101, and one electrode of the capacitor 103 are electrically connected is referred to as a node ND2.

[0131] One of the source and the drain of the transistor 113 is electrically connected to one terminal of the resistor 121, and the other of the source and the drain of the transistor 113 is electrically connected to the other electrode of the capacitor 103. The gate of the transistor 113 is electrically connected to the terminal SH.

[0132] One of the source and the drain of the transistor 114 is electrically connected to the other terminal of the resistor 121, and the other of the source and the drain of the transistor 114 is electrically connected to the other electrode of the capacitor 103. The gate of the transistor 114 is electrically connected to the terminal SHB.

[0133] A node where the other of the source or drain of the transistor 113, the other of the source or drain of the transistor 114, and the other electrode of the capacitor 103 are electrically connected is referred to as a node ND3.

[0134] <Operation Example of Semiconductor Device 200B> The semiconductor device 100D of the semiconductor device 200B has a function of detecting a current (also called an "overcurrent") greater than a prescribed value flowing through the resistor 121 during a discharging operation. Specifically, the semiconductor device 100D outputs an H potential when it detects an overcurrent during a discharging operation. The semiconductor device 100D functions as an overcurrent detection circuit during a discharging operation. The output (potential V OUT ) is supplied to a terminal 225 of the control circuit 210 via a wiring 122.

[0135] When an H potential is supplied to terminal 225, control circuit 210 turns off transistor 213 and stops the discharge operation. By not discharging due to an overcurrent, it is possible to prevent rapid deterioration of the characteristics of secondary battery 300. As a result, it is possible to extend the battery life of secondary battery 300. In addition, it is possible to improve the reliability of secondary battery 300. In addition, it is possible to improve the safety of secondary battery 300.

[0136] [Operation Example of Semiconductor Device 100D] The semiconductor device 100D functions as an overcurrent detection circuit. An operation example of the semiconductor device 100D will be described with reference to Figs. 10 and 11. Figs. 10 and 11 are diagrams showing the operating state of the semiconductor device 100D. As described above, in this embodiment, the potential V R is set to 1.1V, and the potential V RFN is set to 1.25V.

[0137] First, before starting discharge, an H potential is supplied to the terminal SH, and an L potential is supplied to the terminal SHB (see FIG. 10A). Then, the transistor 112 is turned on, and the potential of the node ND2 becomes 1.1 V. Also, the transistor 111 is turned on, and the potential of the node ND1 becomes 1.25 V. Therefore, the potential V OUT becomes the L potential.

[0138] At this time, the potentials of the nodes NDA and NDB are 0 V (reference potential) because no current flows through the resistor 121. When the H potential is supplied to the terminal SH, the transistor 113 is turned on, and the potential of the node ND3 becomes 0 V.

[0139] Next, an L potential is supplied to the terminal SH, and an H potential is supplied to the terminal SHB (see FIG. 10B). Then, the transistor 111 is turned off, and the potential of the node ND1 is held. Similarly, the transistor 112 is turned off, and the potential of the node ND2 is held. In addition, the transistor 113 is also turned off.

[0140] Next, the discharge operation starts. When the discharge starts, a current I C (See Figure 11A.) Current I C flows from node NDB to node NDA, so when discharge starts, the potential of node NDB becomes higher than 0 V. Therefore, the potential of node ND3 also becomes higher than 0 V.

[0141] The value of the overcurrent detected by the semiconductor device 100D can be changed by changing the resistance value of the resistor 121. The resistor 121 may be a variable resistor.

[0142] FIG. 11A shows the resistance R D When the resistance is 150Ω, the current I C In this case, the potential of the node NDB becomes 0.12 V. Therefore, the potential of the node ND3 also becomes 0.12 V. Furthermore, the nodes ND3 and ND2 are capacitively coupled via the capacitor 103. Therefore, the potential of the node ND2 becomes 1.22 V. The potential of the node ND1 remains higher than the potential of the node ND2. Therefore, the potential V OUT remains at L potential.

[0143] FIG. 11B shows the resistance R D When the resistance is 150Ω, the current I C This shows the state when 1.1 mA flows as a current. In this case, the potential of the node NDB becomes 0.165 V. Therefore, the potential of the node ND3 also becomes 0.165 V. For the same reason as above, the potential of the node ND2 becomes 1.265 V. Then, the potential of the node ND1 becomes smaller than the potential of the node ND2, and the potential V OUT becomes H potential.

[0144] In this way, it is possible to detect an overcurrent during a discharging operation. The semiconductor device 100D according to one embodiment of the present invention is configured to detect an overcurrent using the terminal 202, the transistor 213, and the resistor 121 connected in series with the transistor 214. Therefore, it is possible to detect an overcurrent with high accuracy without being affected by variations in the resistance values ​​of the transistors 213 and 214.

[0145] <Modification> 12 shows a configuration example of a semiconductor device 200Ba which is a modified example of the semiconductor device 200B. In this embodiment, in order to reduce repetition of explanation, the differences from the semiconductor device 200B will be mainly described. The semiconductor device 200Ba differs from the semiconductor device 200B in that it has a semiconductor device 100Da instead of the semiconductor device 100D.

[0146] The semiconductor device 100Da has a configuration in which the transistor 113, the transistor 114, and the terminal SHB are removed from the semiconductor device 100D. In the semiconductor device 100Da, the other electrode of the capacitance 103 is electrically connected to the other terminal of the resistor 121. Therefore, in the semiconductor device 200Ba, the node where the other electrode of the capacitance 103 and the other terminal of the resistor 121 are electrically connected is called a node NDB. Also, in the semiconductor device 200Ba, the node where the other of the source or drain of the transistor 214 and one terminal of the resistor 121 are electrically connected is called a node NDA.

[0147] The semiconductor device 100Da has fewer components than the semiconductor device 100D, and therefore occupies a smaller area. Furthermore, the semiconductor device 100Da does not have the terminal SHB, and therefore the terminal 227 can be omitted from the control circuit 210 of the semiconductor device 200Ba.

[0148] [Operation Example of Semiconductor Device 100Da] The semiconductor device 100Da functions as an overcurrent detection circuit in the same manner as the semiconductor device 100D. An operation example of the semiconductor device 100Da will be described with reference to Figures 13 and 14. Figures 13 and 14 are diagrams illustrating the operating state of the semiconductor device 100Da.

[0149] First, before the start of discharge, an H potential is supplied to the terminal SH (see FIG. 13A). Then, the transistor 112 is turned on, and the potential of the node ND2 becomes 1.1 V. Also, the transistor 111 is turned on, and the potential of the node ND1 becomes 1.25 V. Therefore, the potential V OUT becomes the L potential.

[0150] At this time, since no current flows through the resistor 121, the potentials of the nodes NDA and NDB are 0V (reference potential).

[0151] Next, an L potential is supplied to the terminal SH (see FIG. 13B). Then, the transistor 111 is turned off, and the potential of the node ND1 is held. Similarly, the transistor 112 is turned off, and the potential of the node ND2 is held.

[0152] Next, the discharge operation starts. When the discharge starts, a current I C (See Figure 14A.) Current I C flows from node NDB to node NDA, so when discharge begins, the potential of node NDB becomes higher than 0V.

[0153] FIG. 14A shows the resistance R D When the resistance is 150Ω, the current I C 1 shows a state in which 0.8 mA flows as a current. In this case, the potential of the node NDB becomes 0.12 V. Therefore, the potential of the node ND3 also becomes 0.12 V. Furthermore, the node NDB and the node ND2 are capacitively coupled via the capacitor 103. Therefore, the potential of the node ND2 becomes 1.22 V. The potential of the node ND1 remains higher than the potential of the node ND2. Therefore, the potential V OUT remains at L potential.

[0154] FIG. 14B shows the resistance R D When the resistance is 150Ω, the current I C This shows the state when 1.1 mA flows as the potential of node NDB. In this case, the potential of node NDB becomes 0.165 V. For the same reason as above, the potential of node ND2 becomes 1.265 V. Then, the potential of node ND1 becomes smaller than the potential of node ND2, and the potential V OUT becomes H potential.

[0155] In this manner, an overcurrent during a discharging operation can be detected.The semiconductor device 200Ba according to one embodiment of the present invention has fewer components than the semiconductor device 200B, and therefore can occupy a smaller area.

[0156] Note that the semiconductor device according to one embodiment of the present invention should not be interpreted as being limited to the circuit diagrams shown in this embodiment. The semiconductor device according to one embodiment of the present invention may have a circuit configuration similar to that shown in this embodiment.

[0157] This embodiment mode can be implemented in appropriate combination with structures described in other embodiment modes.

[0158] (Embodiment 3) In this embodiment, another structural example of a semiconductor device according to one embodiment of the present invention will be described with reference to drawings.

[0159] <Configuration Example of Semiconductor Device 200C> 15 shows a configuration example of the semiconductor device 200C. The semiconductor device 200C is a modified example of the semiconductor device 200A and the semiconductor device 200B. Therefore, in order to reduce repetition of explanation, the present embodiment will mainly describe the points that are different from the semiconductor device 200A or the semiconductor device 200B.

[0160] The semiconductor device 200C has a control circuit 210A instead of the control circuit 210. The semiconductor device 200C also has both the semiconductor device 100C and the semiconductor device 100D. The control circuit 210A is a modified example of the control circuit 210, and in addition to having the same functions as the control circuit 210, has a function of controlling the semiconductor device 100C and the semiconductor device 100D.

[0161] The control circuit 210A has terminals 225a and 225b as terminals 225, terminals 226a and 226b as terminals 226, and terminals 227a and 227b as terminals 227.

[0162] The terminal 225a is electrically connected to the terminal OUT of the semiconductor device 100C via the wiring 122a. The terminal 225b is electrically connected to the terminal OUT of the semiconductor device 100D via the wiring 122b. The terminal 226a is electrically connected to the terminal SH of the semiconductor device 100C. The terminal 226b is electrically connected to the terminal SH of the semiconductor device 100D. The terminal 227a is electrically connected to the terminal SHB of the semiconductor device 100C. The terminal 227b is electrically connected to the terminal SHB of the semiconductor device 100D.

[0163] The potential generating circuit 220 supplies a potential V R and a function of supplying a potential V RFN and a function of supplying the

[0164] The control circuit 210A has a function of controlling the semiconductor device 100C and the semiconductor device 100D. Therefore, the semiconductor device 200C has a function of detecting an overcurrent during a charging operation and a function of detecting an overcurrent during a discharging operation. By using the semiconductor device 200C, the battery life of the secondary battery 300 can be further extended. In addition, the reliability of the secondary battery 300 can be further improved. In addition, the safety of the secondary battery 300 can be further improved.

[0165] 16, in the semiconductor device 200C, the resistor 121 used in the semiconductor device 100C can be shared with the resistor 121 used in the semiconductor device 100D. This allows the number of components of the semiconductor device 200C to be reduced. In other words, the number of parts constituting the semiconductor device 200C can be reduced.

[0166] In addition, in the semiconductor device 200C, the semiconductor device 100Ca may be used instead of the semiconductor device 100C. Similarly, the semiconductor device 100Da may be used instead of the semiconductor device 100D. By using one or both of the semiconductor device 100Ca and the semiconductor device 100Da in the semiconductor device 200C, the number of components of the semiconductor device 200C can be further reduced. In other words, the number of parts constituting the semiconductor device 200C can be further reduced.

[0167] Note that the semiconductor device according to one embodiment of the present invention should not be interpreted as being limited to the circuit diagrams shown in this embodiment. The semiconductor device according to one embodiment of the present invention may have a circuit configuration similar to that shown in this embodiment.

[0168] This embodiment mode can be implemented in appropriate combination with structures described in other embodiment modes.

[0169] (Embodiment 4) In this embodiment, another structural example of a semiconductor device according to one embodiment of the present invention will be described with reference to drawings.

[0170] <Configuration Example of the Semiconductor Device 200Ad> 17 shows a configuration example of a semiconductor device 200Ad. The semiconductor device 200Ad is a modified example of the semiconductor device 200A. Therefore, in order to reduce repetition of explanation, the following mainly describes the differences between the semiconductor device 200Ad and the semiconductor device 200A.

[0171] The semiconductor device 200Ad has a configuration in which a protection device 250 is added to the semiconductor device 200A. The protection device 250 has a terminal VP, a terminal VN, and a terminal SIG. The terminal VP is electrically connected to the terminal 201, and the terminal VN is electrically connected to the terminal 202. Thus, the terminal VP is electrically connected to the positive electrode of the secondary battery 300, and the terminal VN is electrically connected to the negative electrode of the secondary battery 300. The terminal SIG is also electrically connected to the terminal OUT of the semiconductor device 100C. The terminal SIG is also electrically connected to the terminal 225 of the control circuit 210.

[0172] [Protective device 250] The protection device 250 has a function of preventing damage and malfunction of the control circuit 210 and the semiconductor device 100C due to high-voltage noise such as ESD (Electro Static Discharge), and improving the reliability of the semiconductor device 200Ad.

[0173] Fig. 18A shows an example of an equivalent circuit diagram of the protection device 250. The protection device 250 shown in Fig. 18A has a diode 251a, a diode 251b, a resistor 252, and a capacitor 253. One terminal of the resistor 252 is electrically connected to the terminal SIG, and the other terminal is electrically connected to the anode of the diode 251a. In addition, the cathode of the diode 251a is electrically connected to the terminal VP.

[0174] One electrode of the capacitance 253 is electrically connected to the other terminal of the resistor 252, and the other electrode of the capacitance 253 is electrically connected to the terminal VN. The anode of the diode 251b is electrically connected to the terminal VN, and the cathode is electrically connected to the anode of the diode 251a. That is, one electrode of the capacitance 253 is electrically connected to the cathode of the diode 251b, and the other electrode of the capacitance 253 is electrically connected to the anode of the diode 251b. The capacitance 253 and the diode 251b are connected in parallel.

[0175] In a steady state, the terminal VP is at a high potential and the terminal VN is at a low potential, so that a reverse bias is applied to the diodes 251a and 251b. Therefore, no current flows from the terminal VP to the terminal VN within the protection device 250. However, if the terminal VN unexpectedly becomes at a higher potential than the terminal VP due to an ESD phenomenon or the like, the terminals VP and VN become conductive, and damage and malfunction of the semiconductor device 200Ad can be prevented.

[0176] Furthermore, the terminal SIG is supplied with a signal output from the terminal OUT, which in a steady state is equal to or higher than the potential of the terminal VN and equal to or lower than the potential of the terminal VP. Therefore, in a steady state, no current flows from the terminal SIG to the terminals VP and VN within the protection device 250. However, if a potential higher than the terminal VP or lower than the terminal VN is unexpectedly applied to the terminal SIG due to an ESD phenomenon or the like, the terminal SIG becomes conductive with either the terminal VP or the terminal VN, thereby preventing damage and malfunction of the semiconductor device 200Ad.

[0177] Moreover, the resistor 252 and the capacitor 253 are connected in series and function as a high-pass filter. High-frequency high-voltage noise applied to the terminal SIG is released via the resistor 252 and the capacitor 253 to the terminal VN.

[0178] The resistance value of the resistor 252 is preferably 10 Ω or more and 1 kΩ or less, and more preferably 50 Ω or more and 500 Ω or less. The capacitance value of the capacitor 253 is preferably 0.1 pF or more and 100 pF or less, and more preferably 1 pF or more and 10 pF or less.

[0179] 19A, a capacitor 254 may be provided between the other terminal of the resistor 252 and the terminal VP. The capacitance value of the capacitor 254 may be approximately the same as that of the capacitor 253.

[0180] Also, the diode 251a and the diode 251b can be replaced with transistors. FIG. 18B is an equivalent circuit diagram of the protection device 250 in which the diode 251a is replaced with a transistor 251aT and the diode 251b is replaced with a transistor 251bT. The transistor 251aT can function as a diode by electrically connecting the gate of the transistor 251aT to one of the source or the drain. In this case, one of the source or the drain electrically connected to the gate functions as an anode, and the other of the source or the drain functions as a cathode.

[0181] It is preferable to use OS transistors as the transistors 251aT and 251bT. Since an oxide semiconductor has a band gap of 2 eV or more, it has a significantly small off-state current and a high withstand voltage between the source and drain. That is, the reverse current of a diode is small and a breakdown phenomenon is unlikely to occur.

[0182] Further, the transistors 251aT and 251bT may each be a transistor having a back gate. In the case where a transistor having a back gate is used, the gate and the back gate may be electrically connected to each other (see FIG. 18C). Alternatively, the back gate may be electrically connected to the terminal VN (see FIG. 18D).

[0183] 19B, a plurality of diodes 251a may be connected in parallel. Similarly, a plurality of diodes 251b may be connected in parallel. By connecting diodes 251a and 251b in parallel, the current bypass capability of protection device 250 can be improved. Furthermore, even if some of diodes 251a and 251b are damaged, the function of protection device 250 can be maintained. Therefore, the redundancy of protection device 250 can be improved.

[0184] Also, as shown in Fig. 20A, a plurality of diodes 251a may be connected in series. Similarly, a plurality of diodes 251b may be connected in series. Fig. 20A shows an example in which two diodes 251a and two diodes 251b are connected in series. By connecting a plurality of diodes 251a and a plurality of diodes 251b in series, respectively, the reverse bias per diode is reduced, and therefore the withstand voltage of the protection device 250 can be increased. Therefore, the reliability of the protection device 250 can be increased.

[0185] Fig. 21A is an equivalent circuit diagram of the protection device 250 shown in Fig. 20A in which the diode 251a is replaced with a transistor 251aT and the diode 251b is replaced with a transistor 251bT. Figs. 21B and 21C are equivalent circuit diagrams of the protection device 250 shown in Fig. 20A in which the transistors 251aT and 251bT are transistors having backgates. Fig. 21B shows an example in which the gate and the backgate are electrically connected. Fig. 21C shows an example in which the backgate is electrically connected to the terminal VN.

[0186] Also, as shown in Fig. 20B, a plurality of diodes 251a may be connected in series and in parallel. Similarly, a plurality of diodes 251b may be connected in series and in parallel. Fig. 20B shows an example in which two diodes 251a connected in series and three diodes 251b connected in series are connected in parallel. By connecting a plurality of diodes in series and in parallel, it is possible to increase the redundancy and the withstand voltage of the protection device 250. Therefore, it is possible to increase the reliability of the protection device 250.

[0187] <Configuration Example of Semiconductor Device 200AdA> 22 shows a configuration example of the semiconductor device 200AdA. The semiconductor device 200AdA is a modified example of the semiconductor device 200Ad. Therefore, in order to reduce repetition of explanation, the following mainly describes the differences between the semiconductor device 200AdA and the semiconductor device 200Ad. The semiconductor device 200AdA has a protection device 250A instead of the protection device 250 of the semiconductor device 200Ad.

[0188] In addition, for example, the control circuit 210 and / or the semiconductor device 100C may be configured with a transistor having a back gate, and a potential lower than the negative potential may be supplied to the back gate. In such a case, the protection device 250 may be replaced with the protection device 250A.

[0189] FIG. 23A is an equivalent circuit diagram of the protection device 250A. The protection device 250A shown in FIG. 23A includes two diodes 251c, a capacitance 255, and a resistor 256 in addition to the protection device 250 shown in FIG. 20A. One electrode of the capacitance 255 is electrically connected to the terminal VN, and the other electrode is electrically connected to the anode of the first diode 251c. The cathode of the first diode 251c is electrically connected to the anode of the second diode 251c. The cathode of the second diode 251c is electrically connected to the terminal VN. One terminal of the resistor 256 is electrically connected to the terminal VBG, and the other terminal is electrically connected to the anode of the first diode 251c. The terminal VBG is electrically connected to, for example, the back gate of a transistor included in the control circuit 210 and / or the semiconductor device 100C.

[0190] 23A shows a configuration in which two each of the diodes 251a, 251b, and 251c are connected in series, three or more each of them may be connected in series. Each of the diodes 251a, 251b, and 251c may be formed of one each.

[0191] 23B and 23C are equivalent circuit diagrams of the protection device 250A in which the diode 251a is replaced with a transistor 251aT, the diode 251b is replaced with a transistor 251bT, and the diode 251c is replaced with a transistor 251cT. In FIG. 23B and FIG. 23C, the transistor 251aT, the transistor 251bT, and the transistor 251cT are shown as transistors having backgates, but these transistors may be transistors without backgates. FIG. 23B shows an example in which the gate and the backgate are electrically connected. FIG. 23C shows an example in which the backgate is electrically connected to the terminal VN.

[0192] <Configuration Example of Semiconductor Device 200AdB> 24 shows a configuration example of the semiconductor device 200AdB. The semiconductor device 200AdB is a modified example of the semiconductor device 200Ad. Therefore, in order to reduce repetition of explanation, the following mainly describes the differences between the semiconductor device 200AdB and the semiconductor device 200Ad. The semiconductor device 200AdB has a protection device 250B instead of the protection device 250 of the semiconductor device 200Ad.

[0193] The protection device 250B is a modified example of the protection device 250. The protection device 250B has a terminal SIG_in and a terminal SIG_out instead of the terminal SIG of the protection device 250. The terminal SIG_in is electrically connected to the terminal OUT of the semiconductor device 100C. The terminal SIG_out is electrically connected to the terminal 225 via the wiring 122.

[0194] [Protective device 250B] Fig. 25 shows an example of an equivalent circuit diagram of the protection device 250B. The protection device 250B has a configuration in which a resistor 262 is added to the protection device 250 shown in Fig. 18A. One terminal of the resistor 262 is electrically connected to the other terminal of the resistor 252, and the other terminal of the resistor 262 is electrically connected to the terminal SIG_out.

[0195] The resistance value of resistor 262 may be set similarly to that of resistor 252. The signal output from terminal OUT passes through protective device 250B before being supplied to terminal 225. In this manner, a protective device may be provided in the middle of the signal path.

[0196] <Configuration Example of Semiconductor Device 200Bd> 26 shows a configuration example of the semiconductor device 200Bd. The semiconductor device 200Bd is a modified example of the semiconductor device 200Ad. The semiconductor device 200Bd is also a modified example of the semiconductor device 200B. Therefore, in order to reduce repetition of explanation, the following mainly describes the differences between the semiconductor device 200Bd and the semiconductor device 200Ad. Similarly, the following mainly describes the differences between the semiconductor device 200Bd and the semiconductor device 200B.

[0197] The semiconductor device 200Bd has a semiconductor device 100D instead of the semiconductor device 100C of the semiconductor device 200Ad, so that the terminal SIG is electrically connected to the terminal OUT of the semiconductor device 100D.

[0198] The configuration of the semiconductor device 200Bd can be understood by taking into consideration the semiconductor device 200Ad and the semiconductor device 200B, and therefore a detailed description thereof will be omitted here.

[0199] <Configuration Example of Semiconductor Device 200Cd> 27 shows a configuration example of the semiconductor device 200Cd. The semiconductor device 200Cd is a modified example of the semiconductor device 200Ad. The semiconductor device 200Cd is also a modified example of the semiconductor device 200C. Therefore, in order to reduce repetition of explanation, the following mainly describes the differences between the semiconductor device 200Cd and the semiconductor device 200Ad. Similarly, the following mainly describes the differences between the semiconductor device 200Cd and the semiconductor device 200C.

[0200] The semiconductor device 200Cd has a configuration in which a protection device 250C is added to the semiconductor device 200C. The protection device 250C is a modified example of the protection device 250. The protection device 250C has terminals SIG1 and SIG2 instead of the terminal SIG of the protection device 250. The terminal SIG1 is electrically connected to the terminal OUT of the semiconductor device 100C. The terminal SIG1 is also electrically connected to the terminal 225a of the control circuit 210A. The terminal SIG2 is electrically connected to the terminal OUT of the semiconductor device 100D. The terminal SIG2 is also electrically connected to the terminal 225b of the control circuit 210A.

[0201] [Protective device 250C] 28 shows an example of an equivalent circuit diagram of the protection device 250C. The protection device 250C has a diode 251a_1, a diode 251b_1, a diode 251a_2, a diode 251b_2, a resistor 252_1, a resistor 252_2, a capacitor 253_1, and a capacitor 253_2.

[0202] One terminal of the resistor 252_1 is electrically connected to the terminal SIG1, and the other terminal is electrically connected to the anode of the diode 251a_1. In addition, the cathode of the diode 251a_1 is electrically connected to the terminal VP.

[0203] One electrode of the capacitor 253_1 is electrically connected to the other terminal of the resistor 252_1, and the other electrode of the capacitor 253_1 is electrically connected to the terminal VN. The anode of the diode 251b_1 is electrically connected to the terminal VN, and the cathode is electrically connected to the anode of the diode 251a_1.

[0204] One terminal of the resistor 252_2 is electrically connected to the terminal SIG2, and the other terminal is electrically connected to the anode of the diode 251a_2. In addition, the cathode of the diode 251a_2 is electrically connected to the terminal VP.

[0205] One electrode of the capacitor 253_2 is electrically connected to the other terminal of the resistor 252_2, and the other electrode of the capacitor 253_2 is electrically connected to the terminal VN. The anode of the diode 251b_1 is electrically connected to the terminal VN, and the cathode is electrically connected to the anode of the diode 251a_2.

[0206] The protection device 250C has a configuration in which two protection devices 250 are substantially connected in parallel. Therefore, the above-described modified examples of the protection device 250 can also be applied to the protection device 250C.

[0207] This embodiment mode can be implemented in appropriate combination with structures described in other embodiment modes.

[0208] (Embodiment 5) In this embodiment mode, a structure of a transistor applicable to the semiconductor device described in the above embodiment mode will be described. Specifically, a structure in which transistors having different electrical characteristics are stacked will be described. By using this structure, the degree of freedom in designing the semiconductor device can be increased. In addition, by stacking transistors having different electrical characteristics, the degree of integration of the semiconductor device can be increased.

[0209] The semiconductor device shown in Fig. 29 includes a transistor 400, a transistor 500, and a capacitor 600. Fig. 31A is a cross-sectional view of the transistor 500 in the channel length direction, Fig. 31B is a cross-sectional view of the transistor 500 in the channel width direction, and Fig. 31C is a cross-sectional view of the transistor 400 in the channel width direction.

[0210] The transistor 500 is an OS transistor. Since the off-state current of the transistor 500 is extremely small, the transistor 500 can hold written data voltage or charge for a long period of time by using the transistor 500 as a transistor in a semiconductor device. In other words, the frequency of refresh operations is low or refresh operations are not required, so that the power consumption of the semiconductor device can be reduced.

[0211] 29, the semiconductor device described in this embodiment includes a transistor 400, a transistor 500, and a capacitor 600. The transistor 500 is provided above the transistor 400, and the capacitor 600 is provided above the transistors 400 and 500.

[0212] The transistor 400 is provided over a substrate 311 and includes a conductor 316, an insulator 315, a semiconductor region 313 formed of a part of the substrate 311, and a low-resistance region 314a and a low-resistance region 314b functioning as a source region or a drain region. Note that the transistor 400 can be applied to, for example, the transistor included in the comparator 101 in the above embodiment.

[0213] 31C, the upper surface and the side surface in the channel width direction of the semiconductor region 313 of the transistor 400 are covered with a conductor 316 via an insulator 315. By forming the transistor 400 as a fin type in this manner, the effective channel width is increased, thereby improving the on-characteristics of the transistor 400. In addition, the contribution of the electric field of the gate electrode can be increased, thereby improving the off-characteristics of the transistor 400.

[0214] The transistor 400 may be either a p-channel type or an n-channel type.

[0215] The region where the channel of the semiconductor region 313 is formed, the region nearby, the low resistance region 314a which becomes the source region or the drain region, and the low resistance region 314b preferably contain a semiconductor such as a silicon-based semiconductor, and preferably contain single crystal silicon. Alternatively, they may be formed of a material having Ge (germanium), SiGe (silicon germanium), GaAs (gallium arsenide), GaAlAs (gallium aluminum arsenide), or the like. A configuration using silicon in which the effective mass is controlled by applying stress to the crystal lattice and changing the lattice spacing may be used. Alternatively, the transistor 400 may be a HEMT (High Electron Mobility Transistor) by using GaAs and GaAlAs, or the like.

[0216] Low resistance region 314a and low resistance region 314b contain, in addition to the semiconductor material applied to semiconductor region 313, an element that imparts n-type conductivity, such as arsenic or phosphorus, or an element that imparts p-type conductivity, such as boron.

[0217] The conductor 316 functioning as the gate electrode can be made of a conductive material such as a semiconductor material, such as silicon, containing an element that imparts n-type conductivity, such as arsenic or phosphorus, or an element that imparts p-type conductivity, such as boron, a metal material, an alloy material, or a metal oxide material.

[0218] Since the work function is determined by the material of the conductor, the threshold voltage of the transistor can be adjusted by selecting the material of the conductor. Specifically, it is preferable to use a material such as titanium nitride or tantalum nitride for the conductor. Furthermore, in order to achieve both electrical conductivity and embeddability, it is preferable to use a metal material such as tungsten or aluminum as the conductor in a laminated state, and in particular, it is preferable to use tungsten in terms of heat resistance.

[0219] 29 is just an example and is not limited to this structure, and an appropriate transistor may be used depending on the circuit configuration and driving method. For example, when the semiconductor device is a unipolar circuit including only OS transistors (meaning transistors having the same polarity, such as only n-channel transistors), the structure of the transistor 400 may be the same as that of a transistor 500 including an oxide semiconductor, as shown in FIG 30. Details of the transistor 500 will be described later.

[0220] An insulator 320, an insulator 322, an insulator 324, and an insulator 326 are stacked in this order over the transistor 400.

[0221] As the insulators 320, 322, 324, and 326, for example, silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum nitride oxide, aluminum nitride, or the like can be used.

[0222] In this specification, silicon oxynitride refers to a material having a higher oxygen content than nitrogen, silicon nitride oxide refers to a material having a higher nitrogen content than oxygen, aluminum oxynitride refers to a material having a higher oxygen content than nitrogen, and aluminum nitride oxide refers to a material having a higher nitrogen content than oxygen.

[0223] The insulator 322 may function as a planarizing film that planarizes steps caused by the transistor 400 or the like provided thereunder. For example, the top surface of the insulator 322 may be planarized by a planarization treatment using a chemical mechanical polishing (CMP) method or the like to improve the planarity.

[0224] The insulator 324 is preferably a film having a barrier property that prevents hydrogen or impurities from diffusing from the substrate 311 or the transistor 400 to a region where the transistor 500 is provided.

[0225] As an example of a film having a barrier property against hydrogen, for example, silicon nitride formed by a CVD method can be used. Here, when hydrogen diffuses into a semiconductor element having an oxide semiconductor such as the transistor 500, the characteristics of the semiconductor element may deteriorate. Therefore, it is preferable to use a film that suppresses the diffusion of hydrogen between the transistor 500 and the transistor 400. Specifically, the film that suppresses the diffusion of hydrogen is a film that releases a small amount of hydrogen.

[0226] The amount of desorption of hydrogen can be analyzed, for example, by using thermal desorption spectrometry (TDS). For example, the amount of desorption of hydrogen from the insulator 324 is calculated as 10×10 per area of ​​the insulator 324 when the surface temperature of the film is in the range of 50° C. to 500° C. in the TDS analysis. 15 atoms / cm 2 Less than or equal to 5×10 15 atoms / cm 2 The following is acceptable.

[0227] The insulator 326 preferably has a lower dielectric constant than the insulator 324. For example, the relative dielectric constant of the insulator 326 is preferably less than 4, and more preferably less than 3. For example, the relative dielectric constant of the insulator 326 is preferably 0.7 times or less, and more preferably 0.6 times or less, 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 wirings can be reduced.

[0228] Moreover, the insulator 320, the insulator 322, the insulator 324, and the insulator 326 are embedded with the capacitor 600 or the conductor 328 and the conductor 330 connected to the transistor 500. The conductor 328 and the conductor 330 function as a plug or wiring. In addition, the conductors having the function of a plug or wiring may be collectively given the same reference numeral as a plurality of structures. In addition, in this specification and the like, the wiring and the plug connected to the wiring may be integral. That is, there are cases where a part of the conductor functions as the wiring, and cases where a part of the conductor functions as the plug.

[0229] As the material for each plug and wiring (conductor 328, conductor 330, etc.), a conductive material such as a metal material, an alloy material, a metal nitride material, or a metal oxide material can be used in a single layer or a laminated layer. It is preferable to use a high melting point material such as tungsten or molybdenum that has both heat resistance and conductivity, and tungsten is preferably used. Alternatively, it is preferable to form the plug and wiring from a low resistance conductive material such as aluminum or copper. By using a low resistance conductive material, the wiring resistance can be reduced.

[0230] A wiring layer may be provided over the insulator 326 and the conductor 330. For example, in FIG. 29, an insulator 350, an insulator 352, and an insulator 354 are stacked in this order. A conductor 356 is formed in the insulator 350, the insulator 352, and the insulator 354. The conductor 356 functions as a plug or wiring connected to the transistor 400. Note that the conductor 356 can be provided using a material similar to that of the conductor 328 and the conductor 330.

[0231] Note that, for example, the insulator 350 is preferably an insulator having a barrier property against hydrogen, similar to the insulator 324. The conductor 356 preferably includes a conductor having a barrier property against hydrogen. In particular, a conductor having a barrier property against hydrogen is formed in an opening of the insulator 350 having a barrier property against hydrogen. With this structure, the transistor 400 and the transistor 500 can be separated by a barrier layer, and diffusion of hydrogen from the transistor 400 to the transistor 500 can be suppressed.

[0232] Note that, for example, tantalum nitride or the like may be used as a conductor having a barrier property against hydrogen. By stacking tantalum nitride and tungsten having high conductivity, diffusion of hydrogen from the transistor 400 can be suppressed while maintaining the conductivity of the wiring. In this case, a structure in which the tantalum nitride layer having a barrier property against hydrogen is in contact with the insulator 350 having a barrier property against hydrogen is preferable.

[0233] A wiring layer may be provided on the insulator 354 and the conductor 356. For example, in FIG. 29, an insulator 360, an insulator 362, and an insulator 364 are stacked in this order. A conductor 366 is formed in the insulator 360, the insulator 362, and the insulator 364. The conductor 366 functions as a plug or a wiring. The conductor 366 can be provided using a material similar to that of the conductor 328 and the conductor 330.

[0234] Note that, for example, the insulator 360 is preferably an insulator having a barrier property against hydrogen, similar to the insulator 324. The conductor 366 preferably includes a conductor having a barrier property against hydrogen. In particular, a conductor having a barrier property against hydrogen is formed in an opening of the insulator 360 having a barrier property against hydrogen. With this structure, the transistor 400 and the transistor 500 can be separated by a barrier layer, and diffusion of hydrogen from the transistor 400 to the transistor 500 can be suppressed.

[0235] A wiring layer may be provided on the insulator 364 and the conductor 366. For example, in FIG. 29, an insulator 370, an insulator 372, and an insulator 374 are stacked in this order. A conductor 376 is formed in the insulator 370, the insulator 372, and the insulator 374. The conductor 376 functions as a plug or a wiring. The conductor 376 can be provided using a material similar to that of the conductor 328 and the conductor 330.

[0236] Note that, for example, the insulator 370 is preferably an insulator having a barrier property against hydrogen, similar to the insulator 324. The conductor 376 preferably includes a conductor having a barrier property against hydrogen. In particular, a conductor having a barrier property against hydrogen is formed in an opening of the insulator 370 having a barrier property against hydrogen. With this structure, the transistor 400 and the transistor 500 can be separated by a barrier layer, and diffusion of hydrogen from the transistor 400 to the transistor 500 can be suppressed.

[0237] A wiring layer may be provided over the insulator 374 and the conductor 376. For example, in FIG. 29, an insulator 380, an insulator 382, ​​and an insulator 384 are stacked in this order. A conductor 386 is formed in the insulator 380, the insulator 382, ​​and the insulator 384. The conductor 386 functions as a plug or a wiring. The conductor 386 can be provided using a material similar to that of the conductor 328 and the conductor 330.

[0238] Note that, for example, the insulator 380 is preferably an insulator having a barrier property against hydrogen, similar to the insulator 324. The conductor 386 preferably includes a conductor having a barrier property against hydrogen. In particular, a conductor having a barrier property against hydrogen is formed in an opening of the insulator 380 having a barrier property against hydrogen. With this structure, the transistor 400 and the transistor 500 can be separated by a barrier layer, and diffusion of hydrogen from the transistor 400 to the transistor 500 can be suppressed.

[0239] In the above, a wiring layer including the conductor 356, a wiring layer including the conductor 366, a wiring layer including the conductor 376, and a wiring layer including the conductor 386 have been described, but the semiconductor device of this embodiment is not limited to this. There may be three or fewer wiring layers similar to the wiring layer including the conductor 356, or there may be five or more wiring layers similar to the wiring layer including the conductor 356.

[0240] An insulator 510, an insulator 512, an insulator 514, and an insulator 516 are stacked in this order on the insulator 384. Any of the insulator 510, the insulator 512, the insulator 514, and the insulator 516 is preferably made of a substance that has a barrier property against oxygen or hydrogen.

[0241] For example, the insulator 510 and the insulator 514 are preferably formed using a film having a barrier property that prevents hydrogen or impurities from diffusing from the substrate 311 or a region where the transistor 400 is provided to a region where the transistor 500 is provided. Therefore, a material similar to that of the insulator 324 can be used.

[0242] As an example of a film having a barrier property against hydrogen, silicon nitride formed by a CVD method can be used. Here, when hydrogen diffuses into a semiconductor element having an oxide semiconductor such as the transistor 500, the characteristics of the semiconductor element may deteriorate. Therefore, it is preferable to use a film that suppresses the diffusion of hydrogen between the transistor 500 and the transistor 400. Specifically, the film that suppresses the diffusion of hydrogen is a film that releases a small amount of hydrogen.

[0243] As a film having a barrier property against hydrogen, for example, the insulator 510 and the insulator 514 are preferably made of a metal oxide such as aluminum oxide, hafnium oxide, or tantalum oxide.

[0244] In particular, aluminum oxide has a high blocking effect of preventing the film from permeating both oxygen and impurities such as hydrogen and moisture, which are factors that cause fluctuations in the electrical characteristics of a transistor. Therefore, aluminum oxide can prevent impurities such as hydrogen and moisture from entering the transistor 500 during and after the transistor manufacturing process. In addition, aluminum oxide can suppress the release of oxygen from the oxide that constitutes the transistor 500. Therefore, aluminum oxide is suitable for use as a protective film for the transistor 500.

[0245] For example, the insulator 512 and the insulator 516 can be made of a material similar to that of the insulator 320. By using a material with a relatively low dielectric constant for these insulators, the parasitic capacitance generated between wirings can be reduced. For example, the insulator 512 and the insulator 516 can be made of a silicon oxide film, a silicon oxynitride film, or the like.

[0246] A conductor 518, a conductor constituting the transistor 500 (for example, the conductor 503), and the like are embedded in the insulator 510, the insulator 512, the insulator 514, and the insulator 516. Note that the conductor 518 functions as a plug or wiring connected to the capacitor 600 or the transistor 400. The conductor 518 can be provided using a material similar to that of the conductor 328 and the conductor 330.

[0247] In particular, the insulator 510 and the conductor 518 in the region in contact with the insulator 514 are preferably conductors having barrier properties against oxygen, hydrogen, and water. With this structure, the transistors 400 and 500 can be separated by a layer having barrier properties against oxygen, hydrogen, and water, and diffusion of hydrogen from the transistor 400 to the transistor 500 can be suppressed.

[0248] Above the insulator 516 is a transistor 500 .

[0249] As shown in Figures 31A and 31B, transistor 500 has conductor 503 arranged so as to be embedded in insulator 514 and insulator 516, insulator 520 arranged on insulator 516 and conductor 503, insulator 522 arranged on insulator 520, insulator 524 arranged on insulator 522, oxide 530a arranged on insulator 524, oxide 530b arranged on oxide 530a, conductor 542a and conductor 542b arranged apart from each other on oxide 530b, insulator 580 arranged on conductor 542a and conductor 542b and having an opening formed therebetween overlapping with conductor 542a and conductor 542b, oxide 530c arranged on the bottom and side surfaces of the opening, insulator 550 arranged on the formation surface of oxide 530c, and conductor 560 arranged on the formation surface of insulator 550.

[0250] 31A and 31B, it is preferable that an insulator 544 is disposed between the oxide 530a, the oxide 530b, the conductor 542a, and the conductor 542b and the insulator 580. It is preferable that the conductor 560 has a conductor 560a provided inside the insulator 550 and a conductor 560b provided so as to be embedded inside the conductor 560a, as shown in FIG. 31A and 31B. It is preferable that an insulator 574 is disposed on the insulator 580, the conductor 560, and the insulator 550, as shown in FIG. 31A and 31B.

[0251] In this specification and the like, oxide 530a, oxide 530b, and oxide 530c may be collectively referred to as oxide 530.

[0252] In the transistor 500, a three-layer structure of oxide 530a, oxide 530b, and oxide 530c is shown in the region where a channel is formed and in the vicinity thereof, but the present invention is not limited thereto. For example, a single layer of oxide 530b, a two-layer structure of oxide 530b and oxide 530a, a two-layer structure of oxide 530b and oxide 530c, or a stacked structure of four or more layers may be provided. In addition, in the transistor 500, the conductor 560 is shown as having a two-layer stacked structure, but the present invention is not limited thereto. For example, the conductor 560 may have a single-layer structure or a stacked structure of three or more layers. In addition, the transistor 500 shown in FIG. 29 and FIG. 31A is an example, and the present invention is not limited to the structure, and an appropriate transistor may be used depending on the circuit configuration and the driving method.

[0253] Here, the conductor 560 functions as a gate electrode of the transistor, and the conductors 542a and 542b function as a source electrode and a drain electrode, respectively. As described above, the conductor 560 is formed so as to be embedded in the opening of the insulator 580 and in the region sandwiched between the conductors 542a and 542b. The arrangement of the conductors 560, 542a, and 542b is selected in a self-aligned manner with respect to the opening of the insulator 580. That is, in the transistor 500, the gate electrode can be arranged in a self-aligned manner between the source electrode and the drain electrode. Therefore, the conductor 560 can be formed without providing a margin for alignment, so that the area occupied by the transistor 500 can be reduced. This allows the semiconductor device to be miniaturized and highly integrated.

[0254] Furthermore, since the conductor 560 is formed in a self-aligned manner in the region between the conductor 542a and the conductor 542b, the conductor 560 does not have a region that overlaps with the conductor 542a or the conductor 542b. This makes it possible to reduce the parasitic capacitance formed between the conductor 560 and the conductor 542a and between the conductor 560 and the conductor 542b. This makes it possible to improve the switching speed of the transistor 500 and provide high frequency characteristics.

[0255] The conductor 560 may function as a first gate (also referred to as a top gate) electrode. The conductor 503 may function as a second gate (also referred to as a bottom gate) electrode. In this case, the threshold voltage of the transistor 500 can be controlled by changing the potential applied to the conductor 503 independently of the potential applied to the conductor 560. In particular, by applying a negative potential to the conductor 503, the threshold voltage of the transistor 500 can be made higher than 0 V, and the off-current can be reduced. Therefore, applying a negative potential to the conductor 503 can reduce the drain current when the potential applied to the conductor 560 is 0 V, compared to when a negative potential is not applied.

[0256] The conductor 503 is disposed so as to overlap the oxide 530 and the conductor 560. In this manner, when a potential is applied to the conductor 560 and the conductor 503, the electric field generated from the conductor 560 and the electric field generated from the conductor 503 are connected, and a channel formation region formed in the oxide 530 can be covered.

[0257] In this specification, etc., a transistor structure in which a channel formation region is electrically surrounded by the electric field of a pair of gate electrodes (a first gate electrode and a second gate electrode) is called a surrounded channel (S-channel) structure. In this specification, etc., the surrounded channel (S-channel) structure has a feature that the side and periphery of the oxide 530 in contact with the conductor 542a and the conductor 542b functioning as a source electrode and a drain electrode are I-type like the channel formation region. In addition, the side and periphery of the oxide 530 in contact with the conductor 542a and the conductor 542b are in contact with the insulator 544, so they can be I-type like the channel formation region. In this specification, etc., the I-type can be treated as the same as the high purity intrinsic material described later. In addition, the S-channel structure disclosed in this specification, etc. is different from the fin type structure and the planar type structure. By adopting the S-channel structure, it is possible to obtain a transistor that is more resistant to the short channel effect, in other words, in which the short channel effect is less likely to occur.

[0258] The conductor 503 has a structure similar to that of the conductor 518, and the conductor 503a is formed in contact with the inner walls of the openings of the insulator 514 and the insulator 516, and the conductor 503b is formed further inside. Note that, although the transistor 500 shows a structure in which the conductor 503a and the conductor 503b are stacked, the present invention is not limited to this. For example, the conductor 503 may have a single layer or a stacked structure of three or more layers.

[0259] Here, the conductor 503a is preferably made of a conductive material having a function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, and copper atoms (the impurities are less likely to permeate through). Alternatively, it is preferable to use a conductive material having a function of suppressing the diffusion of oxygen (e.g., at least one of oxygen atoms, oxygen molecules, etc.) (the oxygen is less likely to permeate through). Note that in this specification, the function of suppressing the diffusion of impurities or oxygen refers to the function of suppressing the diffusion of any one or all of the impurities and oxygen.

[0260] For example, the conductor 503a has a function of suppressing the diffusion of oxygen, so that the conductor 503b can be prevented from being oxidized and causing a decrease in conductivity.

[0261] In addition, when the conductor 503 also functions as a wiring, it is preferable that the conductor 503b is made of a highly conductive material containing tungsten, copper, or aluminum as a main component. Note that, although the conductor 503 is illustrated in this embodiment as a stack of the conductors 503a and 503b, the conductor 503 may have a single-layer structure.

[0262] The insulators 520, 522, and 524 function as a second gate insulating film.

[0263] Here, it is preferable that the insulator 524 in contact with the oxide 530 is an insulator containing more oxygen than the oxygen required for the stoichiometric composition. In other words, it is preferable that an excess oxygen region is formed in the insulator 524. By providing an insulator containing such excess oxygen in contact with the oxide 530, the oxygen deficiency (V O In addition, when hydrogen enters an oxygen vacancy in the oxide 530, the defect (hereinafter, V O H.) may function as a donor and generate electrons as carriers. Some of the hydrogen may bond with oxygen that is bonded to a metal atom to generate electrons as carriers. Therefore, a transistor using an oxide semiconductor containing a large amount of hydrogen is likely to have normally-on characteristics. Furthermore, hydrogen in an oxide semiconductor is easily moved by stress such as heat or an electric field. Therefore, if an oxide semiconductor contains a large amount of hydrogen, the reliability of the transistor may be deteriorated. In one embodiment of the present invention, V in the oxide 530 O It is preferable to reduce H as much as possible and make it high-purity intrinsic or substantially high-purity intrinsic. OIn order to obtain an oxide semiconductor with sufficiently reduced H, it is important to remove impurities such as moisture and hydrogen from the oxide semiconductor (sometimes referred to as dehydration or dehydrogenation treatment) and to supply oxygen to the oxide semiconductor to compensate for oxygen vacancies (sometimes referred to as oxygen addition treatment). O By using an oxide semiconductor in which impurities such as H are sufficiently reduced for a channel formation region of a transistor, stable electrical characteristics can be obtained.

[0264] Specifically, it is preferable to use an oxide material from which some oxygen is released by heating as an insulator having an excess oxygen region. An oxide material from which oxygen is released by heating is an oxide material from which the amount of released oxygen converted into oxygen atoms is 1.0×10 18 atoms / cm 3 More than 1.0×10 19 atoms / cm 3 More preferably, 2.0×10 19 atoms / cm 3 or more than 3.0×10 20 atoms / cm 3 The oxide film is one having the above-mentioned properties. The surface temperature of the film during the TDS analysis is preferably in the range of 100° C. or more and 700° C. or less, or 100° C. or more and 400° C. or less.

[0265] In addition, the oxide 530 may be brought into contact with the insulator having the excess oxygen region and subjected to one or more of heat treatment, microwave treatment, and RF treatment. By carrying out such treatment, water or hydrogen in the oxide 530 can be removed. For example, a reaction occurs in the oxide 530 that breaks the bond of VoH, in other words, "V O The reaction "H → Vo + H" occurs, and dehydrogenation can be achieved. Some of the hydrogen generated at this time combines with oxygen to form H 2 As O, it may be removed from the oxide 530 or from an insulator adjacent to the oxide 530. Also, some of the hydrogen may be gettered to the conductor 542.

[0266] Moreover, the microwave treatment is preferably carried out using, for example, an apparatus having a power source for generating high-density plasma, or an apparatus having a power source for applying RF to the substrate side. For example, high-density oxygen radicals can be generated by using a gas containing oxygen and high-density plasma, and by applying RF to the substrate side, the oxygen radicals generated by the high-density plasma can be efficiently introduced into the oxide 530 or an insulator in the vicinity of the oxide 530. The microwave treatment may be carried out under a pressure of 133 Pa or more, preferably 200 Pa or more, and more preferably 400 Pa or more. For example, oxygen and argon are used as gases to be introduced into the apparatus for carrying out the microwave treatment, and the oxygen flow ratio (O 2 / (O 2 +Ar)) is set to 50% or less, preferably 10% or more and 30% or less.

[0267] In addition, in a manufacturing process of the transistor 500, it is preferable to perform heat treatment while the surface of the oxide 530 is exposed. The heat treatment may be performed, for example, at a temperature of 100° C. or higher and 450° C. or lower, more preferably 350° C. or higher and 400° C. or lower. Note that the heat treatment is performed in an atmosphere of nitrogen gas or an inert gas, or an atmosphere containing an oxidizing gas at 10 ppm or higher, 1% or higher, or 10% or higher. For example, the heat treatment is preferably performed in an oxygen atmosphere. In this way, oxygen is supplied to the oxide 530 to reduce oxygen deficiencies (V O ) can be reduced. The heat treatment may be performed under reduced pressure. Alternatively, the heat treatment may be performed in an atmosphere containing 10 ppm or more, 1% or more, or 10% or more of an oxidizing gas in order to compensate for the desorbed oxygen after the heat treatment in a nitrogen gas or inert gas atmosphere. Alternatively, the heat treatment may be performed in an atmosphere containing 10 ppm or more, 1% or more, or 10% or more of an oxidizing gas in order to compensate for the desorbed oxygen. Alternatively, the heat treatment may be performed in an atmosphere containing 10 ppm or more, 1% or more, or 10% or more of an oxidizing gas in succession to a heat treatment in a nitrogen gas or inert gas atmosphere.

[0268] In addition, by performing an oxygen addition process on the oxide 530, the oxygen vacancies in the oxide 530 can be repaired by the supplied oxygen, in other words, the reaction of "Vo+O→null" can be promoted. Furthermore, the supplied oxygen reacts with the hydrogen remaining in the oxide 530 to convert the hydrogen into H 2 O. This causes the hydrogen remaining in the oxide 530 to recombine with the oxygen vacancies and form V. O The formation of H can be suppressed.

[0269] When the insulator 524 has an excess oxygen region, it is preferable that the insulator 522 has a function of suppressing the diffusion of oxygen (eg, oxygen atoms, oxygen molecules, etc.) (the oxygen is less likely to permeate).

[0270] The insulator 522 preferably has a function of suppressing diffusion of oxygen and impurities, so that oxygen contained in the oxide 530 does not diffuse toward the insulator 520. Furthermore, reaction of the conductor 503 with the insulator 524 or oxygen contained in the oxide 530 can be suppressed.

[0271] The insulator 522 may be, for example, aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium aluminate), tantalum oxide, zirconium oxide, lead zirconate titanate (PZT), strontium titanate (SrTiO 3 ), or (Ba,Sr)TiO 3 It is preferable to use an insulator containing a so-called high-k material such as (BST) in a single layer or a multilayer. As transistors become smaller and more highly integrated, problems such as leakage current may occur due to the thinning of the gate insulating film. By using a high-k material as the insulator that functions as the gate insulating film, it is possible to reduce the gate potential during transistor operation while maintaining the physical film thickness.

[0272] In particular, it is preferable to use an insulator containing an oxide of one or both of aluminum and hafnium, which are insulating materials having a function of suppressing the diffusion of impurities and oxygen (the oxygen is unlikely to permeate through them). As an insulator containing an oxide of one or both of aluminum and hafnium, it is preferable to use aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium aluminate), or the like. When the insulator 522 is formed using such a material, the insulator 522 functions as a layer that suppresses the release of oxygen from the oxide 530 and the intrusion of impurities such as hydrogen into the oxide 530 from the periphery of the transistor 500.

[0273] Alternatively, for example, aluminum oxide, bismuth oxide, germanium oxide, niobium oxide, silicon oxide, titanium oxide, tungsten oxide, yttrium oxide, or zirconium oxide may be added to these insulators. Alternatively, these insulators may be nitrided. Silicon oxide, silicon oxynitride, or silicon nitride may be stacked on the above insulators.

[0274] In addition, the insulator 520 is preferably thermally stable. For example, silicon oxide and silicon oxynitride are preferable because they are thermally stable. In addition, by combining a high-k material insulator with silicon oxide or silicon oxynitride, it is possible to obtain the insulator 520 having a thermally stable laminated structure with a high dielectric constant.

[0275] 31A and 31B, the second gate insulating film has a three-layer stack structure, and includes insulators 520, 522, and 524. However, the second gate insulating film may have a single layer, two layers, or four or more layers. In this case, the second gate insulating film is not limited to a stack structure made of the same material, and may have a stack structure made of different materials.

[0276] In the transistor 500, it is preferable to use a metal oxide that functions as an oxide semiconductor for the oxide 530 including the channel formation region. For example, a metal oxide such as In-M-Zn oxide (wherein the element M is one or more selected from aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, etc.) may be used as the oxide 530. In particular, the In-M-Zn oxide that can be used as the oxide 530 is preferably a c-axis aligned crystalline oxide semiconductor (CAAC-OS). Alternatively, it is preferably a cloud-aligned composite oxide semiconductor (CAC-OS). Note that CAAC represents an example of a crystal structure, and CAC represents an example of a function or material configuration. In-Ga oxide or In-Zn oxide may be used as the oxide 530.

[0277] CAC-OS may be called CAC-metal oxide. A part of the CAC-OS or CAC-metal oxide has a conductive function, and a part of the CAC-OS or CAC-metal oxide has an insulating function, and the whole of the CAC-OS or CAC-metal oxide has a semiconductor function. When the CAC-OS or CAC-metal oxide is used in a channel forming region of a transistor, the conductive function is a function of flowing electrons (or holes) as carriers, and the insulating function is a function of not flowing electrons as carriers. By making the conductive function and the insulating function act complementarily, the CAC-OS or CAC-metal oxide can be given a switching function (a function of turning on / off). By separating the respective functions in the CAC-OS or CAC-metal oxide, both functions can be maximized.

[0278] Moreover, the 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, in the material, the conductive region and the insulating region may be separated at the nanoparticle level. In addition, the conductive region and the insulating region may be unevenly distributed in the material. In addition, the conductive region may be observed to be connected in a cloud shape with a blurred periphery.

[0279] In addition, in the CAC-OS or CAC-metal oxide, the conductive regions and the insulating regions may each be dispersed in the material with a size of 0.5 nm to 10 nm, preferably 0.5 nm to 3 nm.

[0280] In addition, the CAC-OS or CAC-metal oxide is composed of components having different band gaps. For example, the CAC-OS or CAC-metal oxide is composed of a component having a wide gap due to an insulating region and a component having a narrow gap due to a conductive region. In this configuration, when carriers are caused to flow, the carriers mainly flow in the component having the narrow gap. In addition, the component having the narrow gap acts complementarily on the component having the wide gap, and carriers also flow in the component having the wide gap in conjunction with the component having the narrow gap. Therefore, when the above CAC-OS or CAC-metal oxide is used in the channel formation region of a transistor, a high current driving force in the on state of the transistor, that is, a large on-current and a high field effect mobility can be obtained.

[0281] That is, CAC-OS or CAC-metal oxide can also be called a matrix composite or a metal matrix composite.

[0282] Metal oxides that function as oxide semiconductors are classified into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors, such as CAAC-OS, polycrystalline oxide semiconductors, nanocrystalline oxide semiconductors (nc-OS), amorphous-like oxide semiconductors (a-like OS), and amorphous oxide semiconductors.

[0283] CAAC-OS has a c-axis orientation and a distorted crystal structure in which multiple nanocrystals are connected in the ab-plane direction. The distortion refers to a portion where the lattice orientation changes between a region with a uniform lattice arrangement and a region with a different uniform lattice arrangement in the region where multiple nanocrystals are connected.

[0284] Nanocrystals are basically hexagonal, but may be non-regular hexagonal. In addition, the lattice arrangement may be pentagonal or heptagonal due to the distortion. In CAAC-OS, it is difficult to confirm clear grain boundaries even near the distortion. In other words, it is found that the formation of grain boundaries is suppressed by the distortion of the lattice arrangement. This is because CAAC-OS can tolerate distortion due to the lack of dense arrangement of oxygen atoms in the ab-plane direction and the change in the bond distance between atoms due to the substitution of metal elements.

[0285] CAAC-OS also tends to have a layered crystal structure (also referred to as a layered structure) in which a layer containing indium and oxygen (hereinafter, In layer) and a layer containing element M, zinc, and oxygen (hereinafter, (M, Zn) layer) are stacked. Note that indium and element M can be substituted for each other, and when element M in an (M, Zn) layer is substituted for indium, it can also be expressed as an (In, M, Zn) layer. When indium in an In layer is substituted for element M, it can also be expressed as an (In, M) layer.

[0286] CAAC-OS is a metal oxide with high crystallinity. On the other hand, it is difficult to confirm clear crystal boundaries in CAAC-OS, so it can be said that the decrease in electron mobility caused by crystal boundaries is unlikely to occur. In addition, since the crystallinity of metal oxides can be decreased by the inclusion of impurities or the generation of defects, CAAC-OS can be said to be a metal oxide with few impurities and defects (oxygen vacancies, etc.). Therefore, metal oxides with CAAC-OS have stable physical properties. As a result, metal oxides with CAAC-OS are resistant to heat and highly reliable.

[0287] The nc-OS has periodic atomic arrangement in a microscopic region (for example, a region of 1 nm to 10 nm, particularly a region of 1 nm to 3 nm). In addition, the nc-OS does not show regularity in the crystal orientation between different nanocrystals. Therefore, no orientation is seen throughout the film. Therefore, depending on the analysis method, the nc-OS may be indistinguishable from an a-like OS or an amorphous oxide semiconductor.

[0288] In-Ga-Zn oxide (also called "IGZO"), a type of metal oxide containing indium, gallium, and zinc, may have a stable structure when made into the above-mentioned nanocrystals. In particular, since IGZO tends to have difficulty in crystal growth in the atmosphere, it may be structurally more stable when made into small crystals (for example, the above-mentioned nanocrystals) rather than large crystals (here, crystals of several mm or several cm).

[0289] The a-like OS is a metal oxide having a structure between the nc-OS and an amorphous oxide semiconductor. The a-like OS has a pore or low-density region. That is, the a-like OS has lower crystallinity than the nc-OS and CAAC-OS.

[0290] Oxide semiconductors (metal oxides) have a variety of structures and each structure has different characteristics. The oxide semiconductor of one embodiment of the present invention may include two or more of an amorphous oxide semiconductor, a polycrystalline oxide semiconductor, an a-like OS, an nc-OS, and a CAAC-OS.

[0291] In addition, it is preferable to use a metal oxide with a low carrier concentration for the transistor 500. In order to reduce the carrier concentration of the metal oxide, the impurity concentration in the metal oxide may be reduced to reduce the defect state density. In this specification and the like, a low impurity concentration and a low defect state density are referred to as high purity intrinsic or substantially high purity intrinsic. Note that examples of impurities in the metal oxide include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, silicon, and the like.

[0292] In particular, hydrogen contained in metal oxide reacts with oxygen that bonds to metal atoms to form water, which may cause oxygen vacancies in the metal oxide. If oxygen vacancies are present in the channel formation region in the metal oxide, the transistor may have normally-on characteristics. Furthermore, defects in which hydrogen has entered the oxygen vacancies may function as donors and generate electrons that serve as carriers. In addition, some of the hydrogen may bond with oxygen that bonds to metal atoms to generate electrons that serve as carriers. Therefore, transistors using metal oxides that contain a large amount of hydrogen tend to have normally-on characteristics.

[0293] A defect in which hydrogen has entered an oxygen vacancy can function as a donor for a metal oxide. However, it is difficult to quantitatively evaluate the defect. Therefore, in a metal oxide, the carrier concentration may be used instead of the donor concentration. Therefore, in this specification, the carrier concentration assuming a state in which no electric field is applied may be used as a parameter of the metal oxide, instead of the donor concentration. In other words, the "carrier concentration" described in this specification may be rephrased as the "donor concentration".

[0294] Therefore, when a metal oxide is used for the oxide 530, it is preferable that hydrogen in the metal oxide is reduced as much as possible. Specifically, in the metal oxide, the hydrogen concentration obtained by secondary ion mass spectrometry (SIMS) is 1×10 20 atoms / cm 3Less than 1 x 10 19 atoms / cm 3 less than 5×10 18 atoms / cm 3 less than 1×10 18 atoms / cm 3 By using a metal oxide in which impurities such as hydrogen are sufficiently reduced for a channel formation region of a transistor, stable electrical characteristics can be obtained.

[0295] In addition, when a metal oxide is used for the oxide 530, the carrier concentration of the metal oxide in the channel formation region is 1×10 18 cm -3 It is preferable that the value is less than 1×10 17 cm -3 More preferably, it is less than 1×10 16 cm -3 More preferably, it is less than 1×10 13 cm -3 More preferably, it is less than 1×10 12 cm -3 The lower limit of the carrier concentration of the metal oxide in the channel formation region is not particularly limited, but is preferably, for example, 1×10 -9 cm -3 It can be said that:

[0296] Furthermore, when a metal oxide is used for the oxide 530, contact between the conductor 542 (conductor 542a and conductor 542b) and the oxide 530 may cause oxygen in the oxide 530 to diffuse into the conductor 542, resulting in the oxidation of the conductor 542. The oxidation of the conductor 542 is likely to result in a decrease in the conductivity of the conductor 542. The diffusion of oxygen in the oxide 530 into the conductor 542 can be rephrased as the conductor 542 absorbing the oxygen in the oxide 530.

[0297] Furthermore, oxygen in the oxide 530 may diffuse into the conductor 542 (conductor 542a and conductor 542b), forming a foreign layer between the conductor 542a and the oxide 530b and between the conductor 542b and the oxide 530b. The foreign layer contains more oxygen than the conductor 542, and is therefore presumed to have insulating properties. In this case, the three-layer structure of the conductor 542, the foreign layer, and the oxide 530b can be regarded as a three-layer structure made of a metal-insulator-semiconductor, and may be called a MIS (Metal-Insulator-Semiconductor) structure or a diode junction structure mainly based on the MIS structure.

[0298] In addition, the above-mentioned different layer is not limited to being formed between the conductor 542 and the oxide 530b. For example, the different layer may be formed between the conductor 542 and the oxide 530c, between the conductor 542 and the oxide 530b, and between the conductor 542 and the oxide 530c.

[0299] The metal oxide that functions as a channel formation region in the oxide 530 preferably has a band gap of 2 eV or more, preferably 2.5 eV or more. In this manner, by using a metal oxide with a wide band gap, the off-state current of the transistor can be reduced.

[0300] The oxide 530 has the oxide 530a below the oxide 530b, so that the diffusion of impurities from structures formed below the oxide 530a to the oxide 530b can be suppressed. Also, the oxide 530 has the oxide 530c on the oxide 530b, so that the diffusion of impurities from structures formed above the oxide 530c to the oxide 530b can be suppressed.

[0301] The oxide 530 preferably has a laminated structure of oxides having different atomic ratios of metal atoms. Specifically, in the metal oxide used for the oxide 530a, the atomic ratio of element M among the constituent elements is preferably larger than the atomic ratio of element M among the constituent elements in the metal oxide used for the oxide 530b. In addition, in the metal oxide used for the oxide 530a, the atomic ratio of element M to In is preferably larger than the atomic ratio of element M to In in the metal oxide used for the oxide 530b. In addition, in the metal oxide used for the oxide 530b, the atomic ratio of In to element M is preferably larger than the atomic ratio of In to element M in the metal oxide used for the oxide 530a. In addition, the oxide 530c can use a metal oxide that can be used for the oxide 530a or the oxide 530b.

[0302] In addition, the energy of the conduction band minimum of the oxide 530a and the oxide 530c is preferably higher than that of the oxide 530b, or in other words, the electron affinity of the oxide 530a and the oxide 530c is preferably smaller than that of the oxide 530b.

[0303] Here, the energy level of the conduction band minimum changes gradually at the junction of the oxide 530a, the oxide 530b, and the oxide 530c. In other words, the energy level of the conduction band minimum at the junction of the oxide 530a, the oxide 530b, and the oxide 530c changes continuously or is a continuous junction. To achieve this, it is preferable to reduce the defect level density of the mixed layer formed at the interface between the oxide 530a and the oxide 530b and the interface between the oxide 530b and the oxide 530c.

[0304] Specifically, the oxides 530a and 530b, and the oxides 530b and 530c have a common element other than oxygen (as a main component), so that a mixed layer with a low density of defect states can be formed. For example, when the oxide 530b is an In-Ga-Zn oxide, the oxides 530a and 530c may be made of an In-Ga-Zn oxide, a Ga-Zn oxide, or a gallium oxide.

[0305] At this time, the main carrier path is the oxide 530b. By configuring the oxide 530a and the oxide 530c as described above, the defect state density at the interface between the oxide 530a and the oxide 530b and at the interface between the oxide 530b and the oxide 530c can be reduced. Therefore, the effect of interface scattering on carrier conduction is reduced, and the transistor 500 can obtain a high on-current.

[0306] Conductors 542a and 542b functioning as a source electrode and a drain electrode are provided on the oxide 530b. As the conductors 542a and 542b, it is preferable to use a metal element selected from aluminum, chromium, copper, silver, gold, platinum, tantalum, nickel, titanium, molybdenum, tungsten, hafnium, vanadium, niobium, manganese, magnesium, zirconium, beryllium, indium, ruthenium, iridium, strontium, and lanthanum, an alloy containing the above-mentioned metal elements as a component, or an alloy combining the above-mentioned metal elements. For example, it is preferable to use tantalum nitride, titanium nitride, tungsten, a nitride containing titanium and aluminum, a nitride containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, an oxide containing strontium and ruthenium, an oxide containing lanthanum and nickel, or the like. In addition, tantalum nitride, titanium nitride, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, and oxides containing lanthanum and nickel are conductive materials that are difficult to oxidize, or materials that maintain conductivity even when oxygen is absorbed, and are therefore preferable.Furthermore, metal nitride films such as tantalum nitride are preferable because they have barrier properties against hydrogen or oxygen.

[0307] 31, the conductor 542a and the conductor 542b are shown as a single-layer structure, but may be a laminated structure of two or more layers. For example, a tantalum nitride film and a tungsten film may be laminated. A titanium film and an aluminum film may be laminated. A two-layer structure in which an aluminum film is laminated on a tungsten film, a two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film, a two-layer structure in which a copper film is laminated on a titanium film, or a two-layer structure in which a copper film is laminated on a tungsten film may be used.

[0308] In addition, there are three-layer structures in which a titanium film or titanium nitride film is laminated with an aluminum film or copper film on the titanium film or titanium nitride film, and a titanium film or titanium nitride film is further formed thereon, and a three-layer structure in which a molybdenum film or molybdenum nitride film is laminated with an aluminum film or copper film on the molybdenum film or molybdenum nitride film, and a molybdenum film or molybdenum nitride film is further formed thereon, etc. Note that a transparent conductive material containing indium oxide, tin oxide, or zinc oxide may also be used.

[0309] 31A, regions 543a and 543b may be formed as low-resistance regions at and near the interface of the oxide 530 with the conductor 542a (conductor 542b). In this case, the region 543a functions as one of the source region and the drain region, and the region 543b functions as the other of the source region and the drain region. A channel formation region is formed in a region sandwiched between the regions 543a and 543b.

[0310] 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 be reduced. Also, a metal compound layer containing a metal contained in the conductor 542a (conductor 542b) and a component of the oxide 530 may be formed in the region 543a (region 543b). In such a case, the carrier density in the region 543a (region 543b) increases, and the region 543a (region 543b) becomes a low-resistance region.

[0311] The insulator 544 is provided to cover the conductor 542a and the conductor 542b and suppresses oxidation of the conductor 542a and the conductor 542b. In this case, the insulator 544 may be provided to cover the side surface of the oxide 530 and to be in contact with the insulator 524.

[0312] The insulator 544 can be a metal oxide containing one or more elements selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, neodymium, lanthanum, magnesium, etc. Alternatively, the insulator 544 can be silicon nitride oxide, silicon nitride, or the like.

[0313] In particular, it is preferable to use, as the insulator 544, an insulator containing an oxide of either or both of aluminum and hafnium, such as aluminum oxide, hafnium oxide, or an oxide containing aluminum and hafnium (hafnium aluminate). In particular, hafnium aluminate has higher heat resistance than a hafnium oxide film. Therefore, it is preferable because it is less likely to crystallize in a heat treatment in a later process. Note that the insulator 544 is not an essential component when the conductors 542a and 542b are made of a material having oxidation resistance or when the conductivity does not decrease significantly even when oxygen is absorbed. It may be designed appropriately depending on the desired transistor characteristics.

[0314] The insulator 544 can prevent impurities such as water and hydrogen contained in the insulator 580 from diffusing to the oxide 530b through the oxide 530c and the insulator 550. The insulator 544 can also prevent the conductor 560 from being oxidized by excess oxygen contained in the insulator 580.

[0315] The insulator 550 functions as a first gate insulating film. The insulator 550 is preferably disposed in contact with the inside (top and side surfaces) of the oxide 530c. The insulator 550 is preferably formed using an insulator that contains excess oxygen and releases oxygen by heating, similar to the insulator 524 described above.

[0316] Specifically, silicon oxide having excess oxygen, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide to which fluorine is added, silicon oxide to which carbon is added, silicon oxide to which carbon and nitrogen are added, and silicon oxide having vacancies can be used. In particular, silicon oxide and silicon oxynitride are preferable because they are stable against heat.

[0317] By providing an insulator that releases oxygen when heated as the insulator 550 in contact with the top surface of the oxide 530c, oxygen can be effectively supplied from the insulator 550 to the channel formation region of the oxide 530b through the oxide 530c. Similarly to the insulator 524, the concentration of impurities such as water or hydrogen in the insulator 550 is preferably reduced. The thickness of the insulator 550 is preferably 1 nm or more and 20 nm or less.

[0318] Furthermore, in order to efficiently supply excess oxygen contained in the insulator 550 to the oxide 530, a metal oxide may be provided between the insulator 550 and the conductor 560. The metal oxide preferably suppresses oxygen diffusion from the insulator 550 to the conductor 560. By providing a metal oxide that suppresses oxygen diffusion, the diffusion of excess oxygen from the insulator 550 to the conductor 560 is suppressed. That is, a decrease in the amount of excess oxygen supplied to the oxide 530 can be suppressed. Furthermore, oxidation of the conductor 560 due to the excess oxygen can be suppressed. As the metal oxide, a material that can be used for the insulator 544 may be used.

[0319] The insulator 550 may have a laminated structure, similar to the second gate insulating film. As transistors become smaller and more highly integrated, problems such as leakage current may occur due to the thinning of the gate insulating film. Therefore, by making the insulator that functions as the gate insulating film a laminated structure of a high-k material and a thermally stable material, it is possible to reduce the gate potential during transistor operation while maintaining the physical film thickness. In addition, a laminated structure that is thermally stable and has a high relative dielectric constant can be obtained.

[0320] Although the conductor 560 functioning as the first gate electrode is shown as having a two-layer structure in FIGS. 31A and 31B, it may have a single-layer structure or a laminated structure of three or more layers.

[0321] The conductor 560a is a hydrogen atom, a hydrogen molecule, a water molecule, a nitrogen atom, a nitrogen molecule, or a nitrogen oxide molecule (N 2 O, NO, NO 2 It is preferable to use a conductive material having a function of suppressing the diffusion of impurities such as copper atoms, etc., etc. Alternatively, it is preferable to use a conductive material having a function of suppressing the diffusion of oxygen (for example, at least one of oxygen atoms, oxygen molecules, etc.). Since the conductor 560a has a function of suppressing the diffusion of oxygen, it is possible to suppress the conductor 560b from being oxidized by the oxygen contained in the insulator 550 and its conductivity from decreasing. As a conductive material having a function of suppressing the diffusion of oxygen, it is preferable to use, for example, tantalum, tantalum nitride, ruthenium, or ruthenium oxide. Also, an oxide semiconductor that can be applied to the oxide 530 can be used as the conductor 560a. In that case, the conductor 560b can be formed by a sputtering method to reduce the electrical resistance value of the conductor 560a and make it a conductor. This can be called an OC (Oxide Conductor) electrode.

[0322] The conductor 560b is preferably made of a conductive material containing tungsten, copper, or aluminum as a main component. The conductor 560b also functions as wiring, so it is preferable to use a conductor with high conductivity. For example, a conductive material containing tungsten, copper, or aluminum as a main component can be used. The conductor 560b may have a layered structure, for example, a layered structure of titanium or titanium nitride and the above conductive material.

[0323] The insulator 580 is provided on the conductor 542a and the conductor 542b via the insulator 544. The insulator 580 preferably has an excess oxygen region. For example, the insulator 580 preferably has silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide to which fluorine has been added, silicon oxide to which carbon has been added, silicon oxide to which carbon and nitrogen have been added, silicon oxide having voids, or a resin. In particular, silicon oxide and silicon oxynitride are preferable because they are thermally stable. In particular, silicon oxide and silicon oxide having voids are preferable because they can easily form an excess oxygen region in a later step.

[0324] The insulator 580 preferably has an excess oxygen region. By providing the insulator 580, which releases oxygen when heated, in contact with the oxide 530c, oxygen in the insulator 580 can be efficiently supplied to the oxide 530 through the oxide 530c. Note that the concentration of impurities such as water or hydrogen in the insulator 580 is preferably reduced.

[0325] The opening of insulator 580 is formed to overlap the region between conductor 542a and conductor 542b, so that conductor 560 is formed so as to be embedded in the opening of insulator 580 and the region sandwiched between conductor 542a and conductor 542b.

[0326] In miniaturizing a semiconductor device, it is necessary to shorten the gate length, but it is also necessary to prevent the conductivity of the conductor 560 from decreasing. If the film thickness of the conductor 560 is increased for that purpose, the conductor 560 may have a shape with a high aspect ratio. In this embodiment, the conductor 560 is provided so as to be embedded in the opening of the insulator 580, so that even if the conductor 560 has a shape with a high aspect ratio, the conductor 560 can be formed without collapsing during the process.

[0327] The insulator 574 is preferably provided in contact with the top surface of the insulator 580, the top surface of the conductor 560, and the top surface of the insulator 550. By forming the insulator 574 by a sputtering method, excess oxygen regions can be provided in the insulator 550 and the insulator 580. This allows oxygen to be supplied from the excess oxygen regions into the oxide 530.

[0328] For example, the insulator 574 can be a metal oxide containing one or more elements selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, magnesium, and the like.

[0329] In particular, aluminum oxide has high barrier properties and can suppress the diffusion of hydrogen and nitrogen even in a thin film with a thickness of 0.5 nm to 3.0 nm. Therefore, aluminum oxide formed by sputtering can function as a barrier film against impurities such as hydrogen as well as an oxygen source.

[0330] An insulator 581 functioning as an interlayer film is preferably provided over the insulator 574. Like the insulator 524, the insulator 581 preferably has a reduced concentration of impurities such as water or hydrogen.

[0331] Conductor 540a and conductor 540b are arranged in openings formed in insulator 581, insulator 574, insulator 580, and insulator 544. Conductor 540a and conductor 540b are provided facing each other with conductor 560 interposed therebetween. Conductor 540a and conductor 540b have the same configuration as conductor 546 and conductor 548, which will be described later.

[0332] An insulator 582 is provided over the insulator 581. The insulator 582 is preferably made of a substance that has a barrier property against oxygen and hydrogen. Therefore, the insulator 582 can be made of a material similar to that of the insulator 514. For example, the insulator 582 is preferably made of a metal oxide such as aluminum oxide, hafnium oxide, or tantalum oxide.

[0333] In particular, aluminum oxide has a high blocking effect of preventing the film from permeating both oxygen and impurities such as hydrogen and moisture, which are factors that cause fluctuations in the electrical characteristics of a transistor. Therefore, aluminum oxide can prevent impurities such as hydrogen and moisture from entering the transistor 500 during and after the transistor manufacturing process. In addition, aluminum oxide can suppress the release of oxygen from the oxide that constitutes the transistor 500. Therefore, aluminum oxide is suitable for use as a protective film for the transistor 500.

[0334] An insulator 586 is provided over the insulator 582. The insulator 586 can be formed using a material similar to that of the insulator 320. By using a material with a relatively low dielectric constant for these insulators, parasitic capacitance between wirings can be reduced. For example, a silicon oxide film, a silicon oxynitride film, or the like can be used as the insulator 586.

[0335] In addition, conductors 546, 548, etc. are embedded in insulators 520, 522, 524, 544, 580, 574, 581, 582, and 586.

[0336] The conductor 546 and the conductor 548 function as a plug or wiring that connects to the capacitor 600, the transistor 500, or the transistor 400. The conductor 546 and the conductor 548 can be formed using a material similar to that of the conductor 328 and the conductor 330.

[0337] After the transistor 500 is formed, an opening may be formed to surround the transistor 500, and an insulator having a high barrier property against hydrogen or water may be formed to cover the opening. By surrounding the transistor 500 with the insulator having a high barrier property, it is possible to prevent moisture and hydrogen from entering from the outside. Alternatively, a plurality of transistors 500 may be collectively surrounded by an insulator having a high barrier property against hydrogen or water. When an opening is formed to surround the transistor 500, for example, an opening reaching the insulator 522 or the insulator 514 is formed, and the insulator having a high barrier property is formed in contact with the insulator 522 or the insulator 514, which is preferable because it serves as part of the manufacturing process of the transistor 500. Note that the insulator having a high barrier property against hydrogen or water may be made of a material similar to that of the insulator 522 or the insulator 514, for example.

[0338] Subsequently, a capacitor 600 is provided above the transistor 500. The capacitor 600 has a conductor 610, a conductor 620, and an insulator 630.

[0339] A conductor 612 may be provided over the conductor 546 and the conductor 548. The conductor 612 functions as a plug or a wiring connected to the transistor 500. The conductor 610 functions as an electrode of the capacitor 600. Note that the conductor 612 and the conductor 610 can be formed at the same time.

[0340] A metal film containing an element selected from molybdenum, titanium, tantalum, tungsten, aluminum, copper, chromium, neodymium, and scandium, or a metal nitride film containing the above-mentioned element (tantalum nitride film, titanium nitride film, molybdenum nitride film, tungsten nitride film), etc. can be used for the conductor 612 and the conductor 610. Alternatively, a conductive material such as indium tin oxide, indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium zinc oxide, or indium tin oxide with added silicon oxide can also be used.

[0341] In this embodiment, the conductor 612 and the conductor 610 have a single-layer structure, but the present invention is not limited to this structure and may have a stacked structure of two or more layers. For example, a conductor having a barrier property and a conductor having high adhesion to the conductor having high conductivity may be formed between a conductor having a barrier property and a conductor having high conductivity.

[0342] The conductor 620 is provided so as to overlap with the conductor 610 with the insulator 630 interposed therebetween. Note that the conductor 620 can be made of a conductive material such as a metal material, an alloy material, or a metal oxide material. It is preferable to use a high melting point material such as tungsten or molybdenum that has both heat resistance and conductivity, and it is particularly preferable to use tungsten. When the conductor 620 is formed simultaneously with other structures such as a conductor, a low resistance metal material such as Cu (copper) or Al (aluminum) may be used.

[0343] An insulator 640 is provided over the conductor 620 and the insulator 630. The insulator 640 can be provided using a material similar to that of the insulator 320. The insulator 640 may also function as a planarizing film that covers the uneven shape underneath.

[0344] With this structure, miniaturization or high integration can be achieved in a semiconductor device including a transistor including an oxide semiconductor.

[0345] Examples of the substrate that can be used in the semiconductor device according to one embodiment of the present invention include a glass substrate, a quartz substrate, a sapphire substrate, a ceramic substrate, a metal substrate (e.g., a stainless steel substrate, a substrate having stainless steel foil, a tungsten substrate, a substrate having tungsten foil, etc.), a semiconductor substrate (e.g., a single crystal semiconductor substrate, a polycrystalline semiconductor substrate, a compound semiconductor substrate, etc.), and an SOI (Silicon on Insulator) substrate. A plastic substrate having heat resistance that can withstand the processing temperature of this embodiment may also be used. Examples of the glass substrate include barium borosilicate glass, aluminosilicate glass, aluminoborosilicate glass, and soda-lime glass. In addition, crystallized glass and the like can be used.

[0346] Alternatively, a flexible substrate, a laminated film, paper containing a fibrous material, or a base film can be used as the substrate. Examples of flexible substrates, laminated films, base films, etc. include the following. For example, there are plastics such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), and polytetrafluoroethylene (PTFE). Alternatively, there are synthetic resins such as acrylic. Alternatively, there are polypropylene, polyester, polyvinyl fluoride, or polyvinyl chloride. Alternatively, there are polyamide, polyimide, aramid, epoxy, inorganic deposition film, or paper. In particular, by manufacturing transistors using a semiconductor substrate, a single crystal substrate, or an SOI substrate, etc., it is possible to manufacture transistors with small variations in characteristics, size, or shape, high current capacity, and small size. When a circuit is constructed using such transistors, it is possible to reduce the power consumption of the circuit or to increase the integration of the circuit.

[0347] Alternatively, a flexible substrate may be used as the substrate, and transistors, resistors, and / or capacitors may be formed directly on the flexible substrate. Alternatively, a peeling layer may be provided between the substrate and the transistors, resistors, and / or capacitors. The peeling layer can be used to separate a semiconductor device from the substrate after a part or whole of the semiconductor device is completed thereon, and transfer the semiconductor device to another substrate. In this case, the transistors, resistors, and / or capacitors can be transferred to a substrate having poor heat resistance or a flexible substrate. For the peeling layer, for example, a laminated structure of inorganic films of a tungsten film and a silicon oxide film, a structure in which an organic resin film such as polyimide is formed on a substrate, a silicon film containing hydrogen, or the like can be used.

[0348] That is, the semiconductor device may be formed on a certain substrate, and then the semiconductor device may be transferred to another substrate. Examples of substrates onto which the semiconductor device may be transferred include substrates on which the above-mentioned transistors can be formed, as well as paper substrates, cellophane substrates, aramid film substrates, polyimide film substrates, stone substrates, wood substrates, cloth substrates (including natural fibers (silk, cotton, hemp), synthetic fibers (nylon, polyurethane, polyester), or regenerated fibers (acetate, cupra, rayon, regenerated polyester), etc.), leather substrates, or rubber substrates. By using these substrates, it is possible to manufacture semiconductor devices that are flexible, that are not easily broken, that have heat resistance, and that are lightweight or thin.

[0349] By providing the semiconductor device on a flexible substrate, for example, even if the secondary battery 300 has a curved or bent shape, the semiconductor device can be provided along the outer shape of the secondary battery. For example, when the secondary battery 300 has a cylindrical shape, the semiconductor device can be provided so as to be wrapped around the side surface of the secondary battery.

[0350] <Transistor modification 1> A transistor 500A shown in Figures 32A and 32B is a modification of the transistor 500 having the structure shown in Figures 31A and 31B. Figure 32A is a cross-sectional view of the transistor 500A in the channel length direction, and Figure 32B is a cross-sectional view of the transistor 500A in the channel width direction. Note that the structures shown in Figures 32A and 32B can also be applied to other transistors included in the semiconductor device of one embodiment of the present invention, such as the transistor 400.

[0351] 32A and 32B includes an insulator 552, an insulator 402, and an insulator 404, and the oxide 530c is a stack of oxides 530c1 and 530c2. The transistor 500A also includes an insulator 552 in contact with a side surface of the conductor 540a, and an insulator 552 in contact with a side surface of the conductor 540b. The transistor 500A also includes an insulator 520 in contact with a side surface of the conductor 540b. The transistor 500A also includes an insulator 520 in contact with a side surface of the conductor 540b.

[0352] 32A and 32B, the insulator 402 is provided over the insulator 512. Furthermore, the insulator 404 is provided over the insulator 574 and the insulator 402.

[0353] 32A and 32B, the insulator 514, the insulator 516, the insulator 522, the insulator 524, the insulator 544, the insulator 580, and the insulator 574 are patterned, and the insulator 404 covers them. That is, the insulator 404 contacts the top surface of the insulator 574, the side surface of the insulator 574, the side surface of the insulator 580, the side surface of the insulator 544, the side surface of the insulator 524, the side surface of the insulator 522, the side surface of the insulator 516, the side surface of the insulator 514, and the top surface of the insulator 402. As a result, the oxide 530 and the like are isolated from the outside by the insulators 404 and 402.

[0354] The insulators 402 and 404 preferably have a high function of suppressing diffusion of hydrogen (for example, at least one of hydrogen atoms, hydrogen molecules, and the like) or water molecules. For example, the insulators 402 and 404 are preferably made of silicon nitride or silicon nitride oxide, which are materials with high hydrogen barrier properties. This can suppress diffusion of hydrogen and the like into the oxide 530, thereby suppressing deterioration in the characteristics of the transistor 500A. Therefore, the reliability of the semiconductor device of one embodiment of the present invention can be improved.

[0355] The insulator 552 is provided in contact with the insulator 581, the insulator 404, the insulator 574, the insulator 580, and the insulator 544. The insulator 552 preferably has a function of suppressing diffusion of hydrogen or water molecules. For example, the insulator 552 is preferably made of an insulator having a high hydrogen barrier property, such as silicon nitride, aluminum oxide, or silicon nitride oxide. In particular, silicon nitride is preferably used as the insulator 552 because it has a high hydrogen barrier property. By using a material having a high hydrogen barrier property as the insulator 552, impurities such as water or hydrogen can be suppressed from diffusing from the insulator 580 or the like to the oxide 530 through the conductor 540a and the conductor 540b. Furthermore, oxygen contained in the insulator 580 can be suppressed from being absorbed by the conductor 540a and the conductor 540b. As described above, the reliability of the semiconductor device of one embodiment of the present invention can be improved.

[0356] The oxide 530c1 contacts the top surface of the insulator 524, the side surface of the oxide 530a, the top surface and side surface of the oxide 530b, the side surfaces of the conductors 542a and 542b, the side surface of the insulator 544, and the side surface of the insulator 580 (see FIG. 32B). The oxide 530c2 contacts the insulator 550.

[0357] The oxide 530c1 may be, for example, an In-Zn oxide. The oxide 530c2 may be the same material as that used for the oxide 530c when the oxide 530c has a single-layer structure. For example, the oxide 530c2 may be a metal oxide having an atomic ratio of In:Ga:Zn=1:3:4, Ga:Zn=2:1, or Ga:Zn=2:5.

[0358] By forming the oxide 530c in a two-layer structure of the oxide 530c1 and the oxide 530c2, the on-current of the transistor can be increased compared to when the oxide 530c has a single-layer structure. Therefore, the transistor can be, for example, a power MOS transistor.

[0359] <Transistor modification 2> A structural example of a transistor 500B will be described with reference to Figures 33A, 33B, and 33C. Figure 33A is a top view of the transistor 500B. Figure 33B is a cross-sectional view of the L1-L2 portion shown by the dashed line in Figure 33A. Figure 33C is a cross-sectional view of the W1-W2 portion shown by the dashed line in Figure 33A. Note that in the top view of Figure 33A, some elements are omitted for clarity.

[0360] The transistor 500B is a modified example of the transistor 500 and can be substituted for the transistor 500. Therefore, in order to avoid repetition of description, the following description will mainly focus on the differences from the transistor 500.

[0361] The conductor 560 functioning as the first gate electrode has a conductor 560a and a conductor 560b on the conductor 560a. The conductor 560a is preferably made of a conductive material having a function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, and copper atoms. Alternatively, it is preferably made of a conductive material having a function of suppressing the diffusion of oxygen (e.g., at least one of oxygen atoms, oxygen molecules, and the like).

[0362] The conductor 560a has a function of suppressing oxygen diffusion, which improves the material selectivity of the conductor 560b. In other words, the presence of the conductor 560a suppresses oxidation of the conductor 560b, thereby preventing a decrease in electrical conductivity.

[0363] It is preferable to provide an insulator 544 so as to cover the top surface and side surface of the conductor 560, the side surface of the insulator 550, and the side surface of the oxide 530c. Note that the insulator 544 may be made of an insulating material having a 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, for example, metal oxides such as magnesium oxide, gallium oxide, germanium oxide, yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, or tantalum oxide, silicon nitride oxide, or silicon nitride may be used.

[0364] Providing the insulator 544 can suppress oxidation of the conductor 560. Furthermore, providing the insulator 544 can suppress diffusion of impurities such as water and hydrogen contained in the insulator 580 to the transistor 500B.

[0365] In the transistor 500B, the conductor 560 overlaps with part of the conductor 542a and part of the conductor 542b, and thus the parasitic capacitance of the transistor 500B is likely to be larger than that of the transistor 500. Thus, the operating frequency of the transistor 500B tends to be lower than that of the transistor 500. However, the productivity of the transistor 500B is higher than that of the transistor 500 because a step of forming an opening in the insulator 580 or the like and burying the conductor 560 and the insulator 550 is not required.

[0366] This embodiment mode can be implemented in appropriate combination with structures described in other embodiment modes.

[0367] (Embodiment 6) In this embodiment, a structural example of a battery that can be used for the secondary battery 300 will be described with reference to the drawings. In this embodiment, an example of a lithium ion secondary battery will be shown, but the battery that can be used for the secondary battery 300 is not limited to a lithium ion secondary battery.

[0368] [Cylindrical secondary battery] FIG. 34A is an external view of a cylindrical secondary battery 715. FIG. 34B is a schematic diagram showing a cross section of a cylindrical secondary battery 715. Inside a hollow cylindrical battery can 702, a battery element is provided in which a strip-shaped positive electrode 704 and a negative electrode 706 are wound with a separator 705 sandwiched therebetween. Although not shown, the battery element is wound around a center pin. One end of the battery can 702 is closed and the other end is open. For the battery can 702, metals such as nickel, aluminum, and titanium that are resistant to corrosion by the electrolyte, or alloys of these metals or alloys of these metals with other metals (for example, stainless steel, etc.) can be used. In addition, it is preferable to coat the battery can with nickel, aluminum, etc. to prevent corrosion by the electrolyte. Inside the battery can 702, the battery element in which the positive electrode, negative electrode, and separator are wound is sandwiched between a pair of opposing insulating plates 708 and 709. A non-aqueous electrolyte (not shown) is injected into the battery can 702 in which the battery element is provided. 2 ) and lithium iron phosphate (LiFePO 4 The positive electrode contains active materials such as lithium ions, the negative electrode is made of carbon materials such as graphite that can absorb and release lithium ions, and the organic solvent such as ethylene carbonate or diethyl carbonate is mixed with LiBF 4 or LiPF 6 The lithium salt may be a non-aqueous electrolyte solution.

[0369] Since the positive and negative electrodes used in the cylindrical secondary battery are wound, it is preferable to form an active material on both sides of the current collector. A positive electrode terminal (positive electrode current collector lead) 703 is connected to the positive electrode 704, and a negative electrode terminal (negative electrode current collector lead) 707 is connected to the negative electrode 706. Both the positive electrode terminal 703 and the negative electrode terminal 707 can be made of a metal material such as aluminum. The positive electrode terminal 703 is resistance-welded to a safety valve mechanism 712, and the negative electrode terminal 707 is resistance-welded to the bottom of the battery can 702. The safety valve mechanism 712 is electrically connected to the positive electrode cap 701 via a PTC element (Positive Temperature Coefficient) 711. The safety valve mechanism 712 cuts off the electrical connection between the positive electrode cap 701 and the positive electrode 704 when the rise in the internal pressure of the battery exceeds a predetermined threshold value. The PTC element 711 is a thermosensitive resistor whose resistance increases when the temperature rises, and the increase in resistance limits the amount of current to prevent abnormal heat generation. The PTC element is made of barium titanate (BaTiO 3 )-based semiconductor ceramics, etc. can be used.

[0370] A lithium ion secondary battery using an electrolyte has a positive electrode, a negative electrode, a separator, an electrolyte, and an exterior body. In a lithium ion secondary battery, the anode (positive electrode) and the cathode (negative electrode) are interchanged during charging and discharging, and the oxidation reaction and the reduction reaction are interchanged, so the electrode with a high reaction potential is called the positive electrode, and the electrode with a low reaction potential is called the negative electrode. Therefore, in this specification, the positive electrode is called the "positive electrode" or "+ electrode (plus electrode)" and the negative electrode is called the "negative electrode" or "- electrode (minus electrode)" whether during charging, discharging, when a reverse bias current is applied, or when a charging current is applied. If the terms anode (positive electrode) and cathode (negative electrode) related to the oxidation reaction and reduction reaction are used, they may be reversed during charging and discharging, which may cause confusion. Therefore, the terms anode (positive electrode) and cathode (negative electrode) are not used in this specification. If the terms anode and cathode are used, it should be specified whether they are used during charging or discharging, and also whether they correspond to the positive electrode (plus) or negative electrode (minus).

[0371] In this embodiment, an example of a lithium ion secondary battery is shown, but the present invention is not limited to lithium ion secondary batteries, and a material having element A, element X, and oxygen can be used as a positive electrode material for a secondary battery. Element A is preferably one or more selected from Group 1 elements and Group 2 elements. As Group 1 elements, for example, alkali metals such as lithium, sodium, and potassium can be used. Furthermore, as Group 2 elements, for example, calcium, beryllium, and magnesium can be used. As element X, for example, one or more selected from metal elements, silicon, and phosphorus can be used. Furthermore, element X is preferably one or more selected from cobalt, nickel, manganese, iron, and vanadium. Representative examples include lithium cobalt composite oxide (LiCoO 2 ) and lithium iron phosphate (LiFePO 4 ) are mentioned.

[0372] The negative electrode includes a negative electrode active material layer and a negative electrode current collector. The negative electrode active material layer may include a conductive assistant and a binder.

[0373] As the negative electrode active material, an element capable of carrying out a charge / discharge reaction by alloying / dealloying with lithium can be used. For example, a material containing at least one of silicon, tin, gallium, aluminum, germanium, lead, antimony, bismuth, silver, zinc, cadmium, indium, etc. can be used. Such elements have a larger capacity than carbon, and silicon in particular has a high theoretical capacity of 4700mAh / g.

[0374] The secondary battery preferably has a separator, which may be made of, for example, cellulose-containing fibers such as paper, nonwoven fabric, glass fiber, ceramics, or synthetic fibers such as nylon (polyamide), vinylon (polyvinyl alcohol-based fiber), polyester, acrylic, polyolefin, or polyurethane.

[0375] 34C shows a state in which a charge control circuit 724 formed or fixed on a flexible substrate 720 is provided along a side surface of a secondary battery 715. The semiconductor device 200 described in the above embodiment can be used as the charge control circuit 724. By providing the charge control circuit 724 on the flexible substrate 720, the charge control circuit 724 can be provided along a curved surface of a cylindrical secondary battery 715. Thus, the space occupied by the charge control circuit 724 can be reduced. Thus, electronic devices including the secondary battery 715 and the charge control circuit 724 can be miniaturized.

[0376] [Flat-shaped secondary battery] Fig. 35A is a diagram showing the appearance of a battery pack 901 including a flat-shaped secondary battery 913. The secondary battery 913 shown in Fig. 35A functions as the battery pack 901 together with a charge control circuit 914 and a connection terminal 911. Fig. 35B shows a state in which the secondary battery 913 and the charge control circuit 914 are separated.

[0377] The charge control circuit 914 is formed or fixed over a flexible substrate 910. The semiconductor device 200 described in the above embodiment mode or the like can be used as the charge control circuit 914. The charge control circuit 914 may have a function of detecting abnormalities such as a micro-short circuit.

[0378] The secondary battery 913 has a terminal 951 and a terminal 952. The charging control circuit 914 is electrically connected to the terminal 951 and the terminal 952. The connection terminal 911 is electrically connected to the terminal 951 and the terminal 952 via the charging control circuit 914. Note that a plurality of connection terminals 911 may be provided, and each of the plurality of connection terminals 911 may be a control signal input terminal, a power supply terminal, or the like.

[0379] The battery pack 901 has an insulating sheet 916 between the charge control circuit 914 and the secondary battery 913. The insulating sheet 916 has a function of preventing unnecessary electrical contact between, for example, the secondary battery 913 and the charge control circuit 914. As the insulating sheet 916, for example, an organic resin film or an adhesive sheet can be used.

[0380] Also, as shown in FIG. 35C, an antenna 917 and a receiving circuit 918 may be provided in the battery pack 901. The antenna may be used to charge the secondary battery 913 in a non-contact manner. The antenna is not limited to a coil shape, and may be, for example, a wire shape or a plate shape. In addition, an antenna such as a planar antenna, an aperture antenna, a traveling wave antenna, an EH antenna, a magnetic field antenna, or a dielectric antenna may be used. The antenna has a function of performing data communication with an external device, for example. As a communication method for data communication, a response method used between the battery pack and other devices, such as NFC, may be used.

[0381] Next, an example of the internal structure of the secondary battery 913 will be described.

[0382] 36A shows the structure of a wound body 950 disposed inside a secondary battery 913. The wound body 950 has a negative electrode 931, a positive electrode 932, and a separator 933. The wound body 950 is a wound body in which the negative electrode 931 and the positive electrode 932 are stacked on top of each other with the separator 933 sandwiched therebetween, and the laminated sheet is wound. Note that the stack of the negative electrode 931, the positive electrode 932, and the separator 933 may be stacked a plurality of times.

[0383] 35A via one of terminal 951 and terminal 952. The positive electrode 932 is connected to the connection terminal 911 shown in FIG 35A via the other of terminal 951 and terminal 952.

[0384] In FIG. 36B, the secondary battery 913 has a wound body 950 in which terminals 951 and 952 are provided inside a housing 930 (also referred to as an "exterior body"). The wound body 950 is impregnated with an electrolyte inside the housing 930. The terminal 952 contacts the housing 930, and the terminal 951 does not contact the housing 930 by using an insulating material or the like. Note that in FIG. 36B, the housing 930 is illustrated separately, but in reality, the wound body 950 is covered by the housing 930, and the terminals 951 and 952 extend outside the housing 930. The housing 930 can be made of a metal material (such as aluminum) or a resin material.

[0385] An insulating material such as a metal material or an organic resin can be used for the housing 930. The housing 930 may be made of a film, in which case a charge control circuit formed on a flexible substrate may be provided on the film.

[0386] 35A shows an example in which insulating sheet 916 is provided on the surface of the housing, and the flexible substrate is fixed with the surface on which the charge control circuit is provided facing inward, but the surface on which the charge control circuit is formed may be facing outward to connect to terminals 951 and 952. In that case, however, the connection portion will be exposed, and there is a risk of electrostatic damage or short circuit, so care must be taken during assembly.

[0387] This embodiment mode can be implemented in appropriate combination with structures described in other embodiment modes.

[0388] (Embodiment 7) In this embodiment, electronic devices to which the semiconductor device according to one embodiment of the present invention can be applied will be described.

[0389] The semiconductor device according to one embodiment of the present invention can be mounted on various electronic devices. Examples of electronic devices include electronic devices with relatively large screens, such as television devices, desktop or notebook personal computers, computer monitors, digital signage, large game machines such as pachinko machines, digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and audio playback devices. Mobile objects such as automobiles, motorcycles, ships, and aircraft can also be considered as electronic devices. The semiconductor device according to one embodiment of the present invention can be used as a charge / discharge control device for a battery built into these electronic devices.

[0390] The electronic device may have an antenna. By receiving a signal through the antenna, images, information, and the like can be displayed on the display unit. In addition, when the electronic device has an antenna and a secondary battery, the antenna may be used for contactless power transmission.

[0391] The electronic device may have sensors (including the ability to measure force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemicals, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared).

[0392] Electronic devices can have various functions, such as a function to display various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function to display a calendar, date, or time, a function to execute various software (programs), a wireless communication function, a function to read out programs or data recorded on a recording medium, and the like.

[0393] Examples of electronic devices including a semiconductor device according to one embodiment of the present invention will be described with reference to FIGS.

[0394] The robot 7100 is equipped with an illuminance sensor, a microphone, a camera, a speaker, a display, various sensors (infrared sensor, ultrasonic sensor, acceleration sensor, piezoelectric sensor, optical sensor, gyro sensor, etc.), and a movement mechanism.

[0395] The microphone has a function of detecting acoustic signals such as the user's voice and environmental sounds. The speaker has a function of emitting audio signals such as voice and warning sounds. The robot 7100 can analyze the audio signal input via the microphone and emit a necessary audio signal from the speaker. The robot 7100 can communicate with the user using the microphone and the speaker.

[0396] The camera has a function of capturing an image of the surroundings of the robot 7100. The robot 7100 also has a function of moving using a moving mechanism. The robot 7100 can capture an image of the surroundings using the camera and detect the presence or absence of an obstacle when moving by analyzing the image. By using a semiconductor device according to one embodiment of the present invention for a secondary battery (battery) of the robot 7100, overcurrent during a charging operation or a discharging operation can be detected. Furthermore, the reliability and safety of the robot 7100 can be improved.

[0397] The flying object 7120 has propellers, a camera, a battery, a memory device, a computing device, etc., and has the ability to fly autonomously.

[0398] For example, image data captured by a camera is stored in a storage device. The flying object 7120 can analyze the image data and detect the presence or absence of an obstacle when moving. In addition, a calculation device can estimate the remaining battery charge from a change in the storage capacity of the battery. By using a semiconductor device according to one embodiment of the present invention for the battery of the flying object 7120, an overcurrent during a charging operation or a discharging operation can be detected. Thus, the reliability and safety of the flying object 7120 can be improved.

[0399] The cleaning robot 7140 has a display arranged on the top surface, multiple cameras arranged on the sides, a brush, operation buttons, various sensors, etc. Although not shown, the cleaning robot 7140 is equipped with tires, a suction port, etc. The cleaning robot 7140 can move by itself, detect dirt, and suck up the dirt from the suction port arranged on the bottom surface.

[0400] For example, the cleaning robot 7140 can analyze an image captured by a camera and determine whether or not there is an obstacle such as a wall, furniture, or a step. When an object that may become entangled in the brush, such as a wire, is detected by image analysis, the rotation of the brush can be stopped. By using a semiconductor device according to one embodiment of the present invention for the battery of the cleaning robot 7140, overcurrent during charging or discharging can be detected. Thus, the reliability and safety of the cleaning robot 7140 can be improved.

[0401] An electric vehicle 7160 is shown as an example of a moving object. The electric vehicle 7160 includes an engine, tires, brakes, a steering device, a camera, and the like. By using a semiconductor device according to one embodiment of the present invention for a battery of the electric vehicle 7160, overcurrent during a charging operation or a discharging operation can be detected. Thus, the reliability and safety of the electric vehicle 7160 can be improved.

[0402] Note that, although an electric vehicle has been described above as an example of a moving object, the moving object is not limited to an electric vehicle. For example, moving objects include trains, monorails, ships, and flying objects (helicopters, unmanned aerial vehicles (drones), airplanes, and rockets). By using a semiconductor device according to one embodiment of the present invention in the battery of these moving objects, overcurrent during charging or discharging can be detected. Therefore, the reliability and safety of these moving objects can be improved.

[0403] A battery including a semiconductor device of one embodiment of the present invention can be incorporated into a TV device 7200 (television receiver), a smartphone 7210, a PC 7220 (personal computer), a PC 7230, a game console 7240, a game console 7260, or the like.

[0404] The smartphone 7210 is an example of a portable information terminal. The smartphone 7210 includes a microphone, a camera, a speaker, various sensors, and a display unit.

[0405] A PC 7220 and a PC 7230 are examples of a notebook PC and a stationary PC, respectively. A keyboard 7232 and a monitor device 7233 can be connected to the PC 7230 wirelessly or via a wire. A game machine 7240 is an example of a portable game machine. A game machine 7260 is an example of a stationary game machine. A controller 7262 is connected to the game machine 7260 wirelessly or via a wire.

[0406] By including the semiconductor device according to one embodiment of the present invention in a battery of an electronic device, overcurrent during charging or discharging can be detected, thereby improving the reliability and safety of the electronic device.

[0407] This embodiment mode can be implemented in appropriate combination with structures described in other embodiment modes. [Explanation of symbols]

[0408] 101: comparator, 102: capacitance, 103: capacitance, 111: transistor, 112: transistor, 113: transistor, 114: transistor, 121: resistor, 122: wiring, 200: semiconductor device, 201: terminal, 202: terminal, 203: terminal, 204: terminal, 210: control circuit, 211: resistor, 212: capacitance, 213: transistor, 214: transistor, 215: diode, 216: diode, 220: potential generating circuit, 221: terminal, 222: terminal, 223: terminal, 224: terminal, 225: terminal, 226: terminal, 227: terminal, 100C: semiconductor device, 100D: semiconductor device, 300: secondary battery

Claims

1. A semiconductor device, a control circuit, a secondary battery, a potential generating circuit, a first transistor, a second transistor, a capacitance, and a resistance, The semiconductor device includes a comparator, the potential generating circuit is electrically connected to a non-inverting input terminal of the comparator; the potential generating circuit is electrically connected to the inverting input terminal of the comparator; an output terminal of the comparator is electrically connected to the control circuit; the control circuit is electrically connected to the gate of the first transistor, the gate of the second transistor, and the potential generating circuit; an inverting input terminal of the comparator is electrically connected to one electrode of the capacitance; the other electrode of the capacitor is electrically connected to the resistor; the resistor is electrically connected to one of the source and the drain of the second transistor; the other of the source and the drain of the second transistor is electrically connected to one of the source and the drain of the first transistor; the other of the source and the drain of the first transistor is electrically connected to the secondary battery; the secondary battery is electrically connected to the control circuit; When the first transistor is in an on state, the secondary battery is charged, When the second transistor is in an on state, the secondary battery is discharged; the control circuit has a function of starting or stopping charging of the secondary battery, the control circuit has a function of starting or stopping discharging the secondary battery, the first transistor and the second transistor each have a semiconductor layer; The battery pack, wherein the semiconductor layer comprises an oxide semiconductor.

2. The power supply includes an overcurrent detection circuit, a control circuit, a secondary battery, a potential generation circuit, a first transistor, a second transistor, a capacitance, and a resistance, The overcurrent detection circuit includes a comparator. the potential generating circuit is electrically connected to a non-inverting input terminal of the comparator; the potential generating circuit is electrically connected to the inverting input terminal of the comparator; an output terminal of the comparator is electrically connected to the control circuit; the control circuit is electrically connected to the gate of the first transistor, the gate of the second transistor, and the potential generating circuit; an inverting input terminal of the comparator is electrically connected to one electrode of the capacitance; the other electrode of the capacitor is electrically connected to the resistor; the resistor is electrically connected to one of the source and the drain of the second transistor; the other of the source and the drain of the second transistor is electrically connected to one of the source and the drain of the first transistor; the other of the source and the drain of the first transistor is electrically connected to the secondary battery; the secondary battery is electrically connected to the control circuit; When the first transistor is in an on state, the secondary battery is charged, When the second transistor is in an on state, the secondary battery is discharged; the control circuit has a function of starting or stopping charging of the secondary battery, the control circuit has a function of starting or stopping discharging the secondary battery, the first transistor and the second transistor each have a semiconductor layer; The battery pack, wherein the semiconductor layer comprises an oxide semiconductor.

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