Power storage device

Abstract

The present invention provides oscillators, amplifier circuits, inverter circuits, amplifier circuits, battery control circuits, battery protection circuits, power storage devices, semiconductor devices, electrical equipment, and the like that are capable of reducing power consumption. [Solution] A semiconductor device (21) includes an oscillator (30) having a transistor (41) having a metal oxide and transistors (42-45). The transistor (41) is turned on, a first potential is applied to the gates of transistors (42) and (43), and the transistor (42) is turned off to maintain the first potential. The oscillator applies a signal (Sv1) corresponding to the first potential to a circuit (31). The circuit (31) performs at least one of shaping and amplifying the signal (Sv1). The transistors (42) and (44) are connected in series, and the transistors (43) and (45) are connected in series. The source or drain of the transistor (45) is electrically connected to the gate of the transistor (44), and the source or drain of the transistor (44) is electrically connected to the gate of the transistor (45).

Description

[Technical Field]

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

[0002] Note that one embodiment of the present invention is not limited to the above technical fields. The technical field relates to an article, a method, or a manufacturing method. is a process, machine, manufacture, or composition of matter. Therefore, one aspect of the present invention disclosed in this specification more specifically relates to The technical fields of the present invention include display devices, light-emitting devices, power storage devices, imaging devices, memory devices, and their driving Examples of the method include a method for operating the device and a method for manufacturing the device. [Background technology]

[0003] Oscillators are widely used in various devices such as wireless communication devices. An example of a negative impedance circuit that may be used is shown. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-324953 Summary of the Invention [Problem to be solved by the invention]

[0005] One aspect of the present invention is a novel oscillator, a novel amplifier circuit, a novel inverter circuit, a novel amplifier circuit, a width circuit, novel battery control circuit, novel battery protection circuit, power storage device, semiconductor device and electrical equipment Another object of the present invention is to provide a semiconductor device that can reduce power consumption. A novel oscillator, inverter circuit, amplifier circuit, battery control circuit, battery protection circuit, and the like can be An object of the present invention is to provide a protection circuit, a power storage device, a semiconductor device, an electric device, and the like.

[0006] Note that the problems of one embodiment of the present invention are not limited to the above-listed problems. This does not preclude the existence of other problems. Problems not mentioned in this section are problems that a person skilled in the art would be able to solve by understanding the specification or can be derived from the descriptions in the drawings, etc., and can be extracted appropriately from these descriptions. One aspect of the present invention is to achieve at least one of the above-listed objects and / or other objects. It solves one problem. [Means for solving the problem]

[0007] One embodiment of the present invention is a semiconductor device including a first transistor, an oscillator, a first wiring, a second wiring, and a first circuit, and the oscillator is connected to each of the first wiring, the second wiring, and the first circuit. and the first transistor has a channel forming region electrically connected to the first transistor. and the oscillator includes a second transistor, a third transistor, and a third transistor. a fourth transistor, a fifth transistor, and a first capacitance element; The gate of the first transistor and the gate of the third transistor are connected to the source of the first transistor and and one of the source and drain of the second transistor. On the other hand, one of the source and drain of the fourth transistor and one of the potentials of the first capacitor element are connected to each other. and one of the source and drain of the third transistor is electrically connected to the fifth transistor. A voltage is applied to one of the source and drain of the transistor and the other electrode of the first capacitor element. The other of the source and drain of the fourth transistor is electrically connected to the fifth transistor. The other of the source and drain of the fifth transistor is electrically connected to the gate of the fifth transistor. , electrically connected to the first circuit and the gate of the fourth transistor, and the first wiring The other of the source and drain of the second transistor and the source and drain of the third transistor The semiconductor device is electrically connected to the other of the drains.

[0008] In the above configuration, the first circuit includes at least one of an inverter and a buffer; an input terminal, a gate of the fourth transistor being electrically connected to the input terminal; The circuit in FIG. 1 has a function of at least one of shaping and amplifying a signal applied to an input terminal. It is a semiconductor device.

[0009] In the above structure, the second to fifth transistors are channel-type It is preferable to have a metal oxide containing indium or zinc in the composite region.

[0010] In the above structure, a second capacitor is provided, and one electrode of the second capacitor is a second capacitance element electrically connected to one of the source and drain of the first transistor; The other electrode is preferably electrically connected to the first wiring.

[0011] In addition, in the above configuration, a second wiring is provided, and the first circuit is a circuit including the first wiring and the second wiring. The first circuit has two or more transistors connected in series between the first circuit and the second circuit. One of the transistors has a source and a drain electrically connected to the first wiring, and a gate is electrically connected to one of the source and drain of the first transistor, and is connected to the first wiring. It is preferable that a low potential signal is applied to the first wiring and a high potential signal is applied to the second wiring.

[0012] In the above configuration, the resistor element, the sixth transistor, and the seventh transistor , and the first wiring is electrically connected to one of the source and the drain of the sixth transistor. The other of the source and drain of the sixth transistor is connected to the source of the seventh transistor. the source and drain of the seventh transistor. The other end of the drain is electrically connected to one electrode of the resistor element, and the other electrode of the resistor element is connected to the first The other of the source and drain of the first transistor is electrically connected to the wiring of The seventh transistor is electrically connected to the source or drain of the seventh transistor and is held at the first potential. During this period, at least one of the sixth transistor and the seventh transistor is turned off. The first wiring has a function of blocking the current flowing between the first wiring and the second wiring. It is preferable that a low potential signal is applied to the first wiring and a high potential signal is applied to the second wiring.

[0013] In the above configuration, the first circuit includes n transistors (n is a natural number of 2 or more). The n transistors of the first circuit are connected in series between the first wiring and the second wiring. The first circuit has n transistors connected to two adjacent transistors. In this case, the source or drain of one transistor is connected to the source or drain of the other transistor. The drain of the fourth transistor is electrically connected to the n It is preferable that the gate of the transistor is electrically connected to at least one of the gates of the transistors.

[0014] In the above configuration, the first circuit includes n transistors (n is a natural number of 2 or more). The n transistors of the first circuit are connected in series between the first wiring and the second wiring. and the (m-1)th transistor of the n transistors included in the first circuit is connected to the The source or drain of the (m-2)th transistor (m is a natural number between 3 and n) n transistors electrically connected to the source or drain of the first circuit One of the source and drain of the first transistor is connected to the first wiring, and the other is connected to the second wiring. The first circuit is electrically connected to the source or drain of the transistor. Of the n transistors, one of the source and drain of the n-th transistor is the The other is connected to the source or drain of the (n-1)th transistor. The gate of the fourth transistor is electrically connected to the n transistors of the first circuit. It is preferable that the gate electrode is electrically connected to at least one gate of the transistor.

[0015] Another embodiment of the present invention is a semiconductor device including any one of the above semiconductor devices, a comparator, and an eighth transistor. a comparator having a non-inverting input terminal and an inverting input terminal connected to a secondary The other is electrically connected to the source and drain of the eighth transistor. The eighth transistor is electrically connected to the other transistor, and the channel forming region of the eighth transistor is formed of indium or The eighth transistor has a metal oxide containing zinc, and when the eighth transistor is turned on, A potential is applied to the other of the non-inverting input terminal and the inverting input terminal to turn the eighth transistor off. By setting the potential of the positive electrode to 1, the comparator has a function of maintaining the first potential. The oscillator has a function of outputting an output signal according to the comparison result of the potentials of the two. The power storage device has a function of blocking current between the first wiring and the second wiring.

[0016] Alternatively, one embodiment of the present invention is a semiconductor device including an oscillator, a first transistor, and a first circuit. The first transistor has a channel formation region formed of a metal oxide containing indium or zinc. the oscillator includes a second transistor, a third transistor, and a fourth transistor; a fifth transistor and a first capacitor; the first circuit has an input terminal; The gate of the second transistor and the gate of the third transistor are connected to the first transistor. and a source and a drain of the second transistor. One of the drains is connected to one of the source and drain of the fourth transistor and the first capacitor element. and one electrode of the second transistor, electrically connected to the source and drain of the third transistor. One of the first and second capacitors is connected to one of the source and drain of the fifth transistor and the other of the first capacitor. The other of the source and drain of the fourth transistor is electrically connected to the first electrode. The fifth transistor is electrically connected to the gate of the fifth transistor and the source and drain of the fifth transistor are electrically connected to the gate of the fifth transistor. The other input is electrically connected to the input terminal of the first circuit and the gate of the fourth transistor. are electrically connected to turn on the first transistor and to connect the gate and A first step of applying a first potential to a gate of a third transistor and a second step of applying a first potential to a gate of the third transistor; a second step of applying a first signal corresponding to the magnitude to an input terminal of the first circuit; the gate of the second transistor and the gate of the third transistor a third step in which the first potential applied to the gate of the first circuit is maintained; and a fourth step of at least one of shaping and amplifying the signal. It is a method.

[0017] In the above configuration, the first wiring, the second wiring, the resistance element, and the sixth transistor the first wiring is connected to the source of the sixth transistor and the seventh transistor; The other of the source and drain of the sixth transistor is connected to the seventh transistor. the source and drain of the seventh transistor are connected to one of the source and drain of the seventh transistor; The other electrode is electrically connected to one electrode of the resistor element, and the other electrode of the resistor element is electrically connected to the second wiring. The other of the source and drain of the first transistor is connected to a seventh transistor. In the first step, the first wiring is electrically connected to the source or drain of the A low potential signal is applied to the first wiring and a high potential signal is applied to the second wiring. After the first transistor is turned off, the sixth transistor and the seventh transistor are turned on. At least one of the transistors is turned off, and the current flowing between the first wiring and the second wiring is cut off. It is preferable that the

[0018] In the above structure, a second capacitor is provided, and one electrode of the second capacitor is a second capacitance element electrically connected to one of the source and drain of the first transistor; The other electrode is preferably electrically connected to the first wiring.

[0019] In the above configuration, the first circuit is at least one of an inverter and a buffer. It is preferred that the compound has the following structure:

[0020] In the above structure, the second to fifth transistors are channel-type It is preferable to have a metal oxide containing indium or zinc in the composite region.

[0021] Alternatively, one embodiment of the present invention is a power supply including an oscillator, a first transistor, a first circuit, and a second a first transistor including a circuit and a first wiring, and a channel forming region including indium or a metal oxide containing zinc, and the oscillator includes a second transistor and a third transistor. a fourth transistor, a fifth transistor, and a first capacitance element, The first circuit has an input terminal, and the first wiring is connected to the source and drain of the second transistor. one of the source and drain of the third transistor is electrically connected to the other of the first transistor and the other of the source and drain of the third transistor. , the gate of the second transistor and the gate of the third transistor are connected to the first transistor the source and drain of the second transistor are electrically connected to one of the source and drain of the first transistor. The other of the source and drain of the fourth transistor is connected to one of the source and drain of the first capacitor. One electrode of the element is electrically connected to the source and drain of a third transistor. The other of the first and second capacitor elements is connected to one of the source and drain of the fifth transistor and the other of the first capacitor element. and the other of the source and drain of the fourth transistor is electrically connected to a gate of the fifth transistor; a source and drain of the fifth transistor; the other drain is electrically connected to the first circuit and to the gate of the fourth transistor; The second circuit is electrically connected to the positive electrode of the secondary battery and applies a first potential to the second circuit. A first step, a second step of holding the first potential, and a second circuit of transmitting a second signal. A third step in which the second circuit outputs a low potential signal to the first wiring, and a fourth step in which the second circuit outputs a low potential signal to the first wiring. and the first transistor is turned on, and the gate of the second transistor and the third transistor are connected to each other. A fifth step of applying a second potential to the gate of the transistor and generating a second potential at the oscillator in response to the second potential. a sixth step of applying the second signal to an input terminal of the first circuit; The transistor is turned off, and the gate of the second transistor and the gate of the third transistor are a seventh step in which the second potential applied to the first circuit is maintained; and the first circuit shapes the second signal. and an eighth step of performing at least one of: do.

[0022] In the above configuration, the second wiring, the resistor element, the sixth transistor, and the seventh a sixth transistor, and the first wiring is connected to one of the source and drain of the sixth transistor. On the other hand, the other of the source and drain of the sixth transistor is connected to the source of the seventh transistor. and the other of the source and drain of the seventh transistor is a resistor element. One electrode of the resistor element is electrically connected to the first wiring, and the other electrode of the resistor element is electrically connected to the second wiring. The other of the source and drain of the first transistor is connected to the source or drain of the seventh transistor. and in a seventh step, turning the first transistor into an off state. After that, at least one of the sixth transistor and the seventh transistor is turned off. However, it is preferable that the current flowing between the first wiring and the second wiring is interrupted.

[0023] In the above structure, a second capacitor is provided, and one electrode of the second capacitor is a second capacitance element electrically connected to one of the source and drain of the first transistor; The other electrode is preferably electrically connected to the first wiring.

[0024] In the above configuration, the first circuit is at least one of an inverter and a buffer. It is preferred that the compound has the following structure:

[0025] In the above structure, the second to fifth transistors are channel-type It is preferable to have a metal oxide containing indium or zinc in the composite region. [Effects of the Invention]

[0026] According to one aspect of the present invention, a novel oscillator, a novel amplifier circuit, a novel inverter circuit, a novel Novel amplifier circuit, novel battery control circuit, novel battery protection circuit, power storage device, semiconductor device and electric Furthermore, according to one embodiment of the present invention, power consumption can be reduced. A novel oscillator, inverter circuit, amplifier circuit, battery control circuit, and battery protection circuit are provided. A circuit, a power storage device, a semiconductor device, an electric device, and the like can be provided.

[0027] The effects of one embodiment of the present invention are not limited to the effects listed above. This does not preclude the existence of other effects. Other effects may be affected by this item, as described below. The effects not mentioned in this section are obvious to a person skilled in the art from the description or can be derived from the descriptions in the drawings, etc., and can be extracted appropriately from these descriptions. One aspect of the present invention has at least the above-listed effects and / or other effects. Therefore, one aspect of the present invention is to provide the above-listed However, there are cases where the effect is not significant. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 is a circuit diagram showing an example of the configuration of a semiconductor device. [Figure 2] FIG. 2 is a circuit diagram showing an example of the configuration of a semiconductor device. [Figure 3] Fig. 3A is a diagram showing an example of a circuit configuration; Fig. 3B is a diagram showing an example of a circuit configuration; Fig. 3C is a diagram showing an example of a circuit configuration; and Fig. 3D is a diagram showing an example of a circuit configuration. [Figure 4] Fig. 4A is a diagram showing an example of a circuit configuration. Fig. 4B is a diagram showing an example of a circuit configuration. Fig. 4C is a diagram showing an example of a circuit configuration. Fig. 4D is a diagram showing an example of a circuit configuration. Fig. 4E is a diagram showing an example of a circuit configuration. [Figure 5] FIG. 5 is a timing chart illustrating an example of the operation of the semiconductor device. [Figure 6] 6A and 6B are circuit diagrams showing examples of the configuration of a semiconductor device. [Figure 7] 7A and 7B are circuit diagrams showing examples of the configuration of an amplifier circuit. [Figure 8] Fig. 8A is a circuit diagram showing an example of a secondary battery and a semiconductor device, and Fig. 8B is a diagram illustrating an example of the operation of the semiconductor device. [Figure 9] FIG. 9 is a cross-sectional view showing an example of the configuration of a semiconductor device. [Figure 10] 10A, 10B, and 10C are cross-sectional views illustrating examples of the structure of a transistor. [Figure 11] 11A, 11B, and 11C are top views, cross-sectional views, and cross-sectional views illustrating examples of the structure of a transistor. [Figure 12]12A is a top view illustrating an example of the structure of a transistor, FIG. 12B is a cross-sectional view illustrating an example of the structure of a transistor, and FIG. 12C is a cross-sectional view illustrating an example of the structure of a transistor. [Figure 13] 13A is a top view illustrating an example of the structure of a transistor, FIG. 13B is a cross-sectional view illustrating an example of the structure of a transistor, and FIG. 13C is a cross-sectional view illustrating an example of the structure of a transistor. [Figure 14] 14A is a top view illustrating an example of the structure of a transistor, FIG. 14B is a cross-sectional view illustrating an example of the structure of a transistor, and FIG. 14C is a cross-sectional view illustrating an example of the structure of a transistor. [Figure 15] 15A is a top view illustrating an example of the structure of a transistor, FIG. 15B is a cross-sectional view illustrating an example of the structure of a transistor, and FIG. 15C is a cross-sectional view illustrating an example of the structure of a transistor. [Figure 16] 16A is a top view illustrating an example of the structure of a transistor, FIG. 16B is a cross-sectional view illustrating an example of the structure of a transistor, and FIG. 16C is a cross-sectional view illustrating an example of the structure of a transistor. [Figure 17] FIG. 17 is a cross-sectional view showing an example of the configuration of a semiconductor device. [Figure 18] FIG. 18 is a cross-sectional view showing an example of the configuration of a semiconductor device. DETAILED DESCRIPTION OF THE INVENTION

[0029] Hereinafter, embodiments will be described with reference to the drawings. It is possible to implement the present invention in various ways without departing from the spirit and scope of the present invention. It will be readily apparent to those skilled in the art that various modifications may be made to the details of the present invention. However, the present invention should not be construed as being limited to the description of the following embodiments.

[0030] In this specification, the ordinal numbers "first," "second," and "third" refer to the constituent elements. The numbers are added to avoid confusion and do not limit the number of components. The order of the components is not limited. The element referred to as "first" in one embodiment may be used in other embodiments or in the claims. In addition, for example, the second component may be the component referred to as "second" in the specification. A component referred to as "first" in one embodiment may be used in other embodiments, or It may be omitted in the claims.

[0031] In the drawings, elements that are the same or have similar functions, elements that are made of the same material, or In some cases, the same reference numerals may be used to designate elements that are formed at the same time, and repeated explanations thereof will be omitted. It may be omitted.

[0032] In addition, the position, size, range, etc. of each component shown in the drawings etc. are to be clearly indicated in order to facilitate understanding of the invention. Therefore, the actual location, size, range, etc. may not be shown. The invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings, etc. For example, in the actual manufacturing process, resist masks and other materials may be damaged unintentionally by etching or other processes. However, this may not be reflected in the diagram to make it easier to understand.

[0033] Also, in top views (also called "plan views") and perspective views, etc., the drawings are easy to understand. Therefore, descriptions of some components may be omitted.

[0034] In addition, the terms "electrode" and "wiring" used in this specification and the like refer to these components functionally. This is not a limitation. For example, an "electrode" may be used as part of a "wiring." , and vice versa. Furthermore, the terms "electrode" and "wiring" may be used interchangeably with "electrodes" and "wiring." This also includes cases where the wiring is formed integrally.

[0035] In this specification, a "terminal" refers to, for example, a wiring or an electrode connected to a wiring. In addition, in this specification, a part of the "wiring" may be referred to as a "terminal." .

[0036] In this specification, the terms "above" and "below" refer to the positional relationship of components directly above or below each other. It is not limited to being directly under and in direct contact with the insulating layer A. If the expression is "electrode B", electrode B does not need to be formed directly on insulating layer A, The case where other components are included between the insulating layer A and the electrode B is not excluded.

[0037] The source and drain functions may also be different when using transistors with different polarities. When the direction of current changes during circuit operation, they may be interchanged depending on the operating conditions. Therefore, it is difficult to determine which is the source and which is the drain. In this specification, the terms source and drain can be used interchangeably. It shall be.

[0038] In addition, in this specification, "electrically connected" refers to a direct connection and a connection without any This includes cases where the device is connected via "something that has an electrical effect." "Something with an electrical effect" means something that enables the transmission and reception of electrical signals between connected objects. Therefore, even if it is expressed as "electrically connecting," In real circuits, there are cases where there are no physical connections and only wires are extended. do.

[0039] In this specification, "parallel" means that two lines are at an angle of -10° to 10°. This means that the angle between -5° and 5° is also included. Also, "perpendicular" and "orthogonal" mean, for example, that two straight lines are at an angle of 80° or more and 100° or less. Therefore, it also includes cases where the angle is between 85° and 95°.

[0040] In this specification and elsewhere, counting values ​​and measurement values ​​are referred to as "the same," "the same," "etc." When we say "good" or "uniform," we mean plus or minus 2 unless otherwise specified. It is assumed that there is a 0% margin of error.

[0041] In this specification, when etching is performed after forming a resist mask, Unless otherwise specified, the resist mask is removed after the etching process is completed. do.

[0042] Also, a voltage is a potential between a certain potential and a reference potential (for example, a ground potential or a source potential). Therefore, "voltage" and "potential" can be used interchangeably. In this specification and elsewhere, unless otherwise specified, the terms "voltage" and "potential" are used. It shall be possible to replace it.

[0043] Even when written as "semiconductor," if the conductivity is sufficiently low, it may be called an "insulator." Therefore, it is possible to use "semiconductor" instead of "insulator." In this case, the boundary between "semiconductor" and "insulator" is vague, and it is difficult to make a strict distinction between the two. Therefore, the terms "semiconductor" and "insulator" in this specification can be read interchangeably. It may be possible.

[0044] Also, even if a material is written as a "semiconductor," if the material has a sufficiently high conductivity, it may be written as a "conductor." Therefore, it is possible to use "semiconductor" instead of "conductor." In this case, the boundary between "semiconductor" and "conductor" is vague, and it is difficult to make a strict distinction between the two. Therefore, the terms "semiconductor" and "conductor" in this specification can be read interchangeably. It may be possible.

[0045] In this specification, the "on state" of a transistor refers to the state where the source of the transistor is This refers to a state in which the source and drain are considered to be electrically short-circuited (also called the "conduction state"). The "off state" of a transistor means that the source and drain of the transistor are electrically isolated. This refers to a state in which the conduction state can be considered to be non-conductive (also called a "non-conductive state").

[0046] In this specification, the term "on-state current" refers to the amount of current that flows through the source when a transistor is in an on-state. The term "off-state current" may refer to the current that flows between the gate and drain of a transistor. It may refer to the current that flows between the source and drain when the device is in the off state.

[0047] In this specification, a high potential signal refers to a power supply potential that is higher than a low potential signal. The low potential signal indicates a power supply potential that is lower than the high potential signal. The potential can also be used as a high potential signal or a low potential signal. For example, if a high potential signal is connected to ground, In the case of a potential, a low potential signal is a potential lower than ground potential, and when a low potential signal is at ground potential, In this case, a high potential signal is a potential higher than the ground potential. A high potential signal is also called a high power supply potential. A low potential signal may also be called a low power supply potential.

[0048] In this specification, the term "gate" refers to a gate electrode and a part or all of a gate wiring. The gate wiring is the part that is connected to the gate electrode of at least one transistor and another This refers to wiring that electrically connects electrodes or other wiring.

[0049] In this specification, the source includes a source region, a source electrode, and a source wiring. The source region is the part of the semiconductor layer where the resistivity is below a certain value. The source electrode refers to the conductive layer connected to the source region. The source wiring is a wiring that connects the source electrode of at least one transistor with another electrode or another wiring. This refers to wiring that electrically connects wires.

[0050] In this specification, the drain includes a drain region, a drain electrode, and a drain electrode. The drain region is a part or all of the semiconductor layer that has a certain resistivity. The drain electrode is the conductive area connected to the drain region. The drain wiring is a layer that connects at least one transistor drain electrode and This refers to wiring for electrically connecting to another electrode or another wiring.

[0051] (Embodiment 1) In this embodiment, an example of a semiconductor device according to one embodiment of the present invention will be described.

[0052] <Example of semiconductor device> The semiconductor device 21 shown in FIG. 1 includes an oscillator 30, a circuit 31, a circuit 32, a wiring VD1, and , and wiring VS1. The wiring VD1 and wiring VS1 respectively connect the oscillator 30, the circuit 31 and the circuit 32. For example, a high potential signal is applied to the wiring VD1. A low potential signal is applied to the wiring VS1.

[0053] The oscillator 30 includes a transistor 42, a transistor 43, a transistor 44, and a transistor The circuit 32 has a terminal V BI1 is electrically connected to the oscillator 30 etc. The terminal VBI1 supplies the signal Sv1 to the oscillator 30 It has the function of providing the following:

[0054] One of the source and drain of transistor 42 is connected to the source and drain of transistor 44. One of the drains, one of the electrodes of the capacitance element 51, and the node ND1 are electrically connected to One of the source and drain of the transistor 43 is connected to the source of the transistor 45. and a drain electrode electrically connected to the other electrode of the capacitor 51 and the node ND2. The other of the source and drain of the transistor 44 is connected to the The gate of the transistor 4 is electrically connected to the terminal OU2 and the node ND3. The other of the source and drain of transistor 5 is connected to the gate of transistor 44, terminal OU1, and node The other of the source and drain of the transistor 42 is electrically connected to the node ND4. The other of the source and drain of the transistor 43 is electrically connected to a wiring VS1. do.

[0055] The terminal OU1 is electrically connected to a terminal IN2 that the circuit 31 has.

[0056] Oscillator 30 also preferably includes transistor 54 and transistor 55. In FIG. 1, one of the source and drain of the transistor 54 is connected to the transistor 45. and the other of the source and drain of the transistor 54. The source and gate of the transistor 55 are electrically connected to the wiring VD1. One of the drains is electrically connected to the gate of the transistor 44. The other of the source and drain of 55 and the gate are electrically connected to a wiring VD1.

[0057] Moreover, instead of the transistors 54 and 55, resistor elements may be used. Alternatively, a plurality of transistors connected in series with their gates electrically connected to each other may be used. It's fine.

[0058] The oscillator 30 may be configured, for example, by adjusting the capacitance of the capacitive element 51, the capacitance of the transistor 44, and the capacitance of the transistor 55. The threshold voltage of transistor 45, the current flowing through transistor 44 and transistor 45, etc. It has the function of outputting a signal of the specified frequency to terminal OU1 etc.

[0059] The oscillator 30 is a Source Coupled Voltage Controlled It is sometimes called an oscillator.

[0060] The gates of the transistors 42 and 43 are electrically connected to the terminal VBI1. The magnitude of the drain current of the transistor 42 and the transistor 43 is Therefore, the oscillator 30 can be controlled by the signal Sv1 given by the , the magnitude of the current flowing through transistor 44 and transistor 44 is controlled by signal Sv1. It can be controlled.

[0061] Also, by changing the signal Sv1, the frequency of the oscillator 30 can be adjusted. .

[0062] The circuit 31 has an inverter 53. Note that the circuit 31 includes a buffer circuit instead of the inverter. The circuit 31 may have functions such as shaping and amplifying the signal applied to the terminal IN2. It is preferred that the compound has the following structure:

[0063] The circuit 31 shown in FIG. 1 includes an inverter 53, a transistor 61, a terminal IN2, and a terminal The inverter 53 converts the signal input from the terminal IN2 into the signal at the terminal OU3. It has the function of outputting.

[0064] A high potential signal is applied to the inverter 53 from the wiring VD1. One of the source and drain is electrically connected to the inverter 53, and the other is electrically connected to the wiring VS1. When the transistor 61 is in the ON state, the transistor 61 is connected to the wiring VS1. A low potential signal is given to the inverter 53 via the

[0065] The gate of the transistor 61 is electrically connected to the terminal VBI1. The magnitude of the drain current is controlled by the signal Sv1 given from the terminal VBI1. Therefore, in the circuit 31, the wiring VD1 and the wiring VS The current flowing between the output terminals 1 and 2 can be controlled by the signal Sv1. The power consumption of the circuit 31 can be reduced by not passing the above power.

[0066] The circuit 32 shown in FIG. 1 includes a transistor 41, a terminal VBI1, a terminal SH1, and a terminal E One of the source and drain of the transistor 41 is connected to the terminal VBI1. The gate of the transistor 41 is electrically connected to the terminal SH1. The circuit 32 preferably includes a capacitor 52. In FIG. One electrode of the transistor 41 is electrically connected to the terminal SH1, and the other electrode is connected to the wiring VS1. are electrically connected.

[0067] The circuit 32 will be described in detail later.

[0068] The transistor included in the semiconductor device 21 may have a back gate. In the body device 21, transistor 42, transistor 43, transistor 44, The back gates of transistors 45, 54, 55 and 61 The gate is electrically connected to the source or drain of each transistor, The back gate of the transistor 41 is electrically connected to the wiring VS1.

[0069] In the semiconductor device 21 shown in FIG. Transistor 44, transistor 45, transistor 54, transistor 55 and transistor 1. In the example shown, the back gate of transistor 61 is electrically connected to the source or drain. A desired potential may be applied to the back gate of the transistor, and the potential may be fixed. For example, the potential of the wiring VS1 may be used. Alternatively, the potential applied to the back gate may be any of several It may be a potential selected from the potentials, or it may be a value that changes with time. The back gate is electrically connected to the gate pair with the gate insulator and the semiconductor layer sandwiched therebetween. This may be done.

[0070] 3A, 3B, 3C, and 3D show examples of specific configurations of the circuit 32. 32 has the function of outputting and holding a desired potential from the terminal VBI1.

[0071] The circuit 32 shown in FIG. 3A includes a transistor 41, a transistor 46a, and a transistor 3A, the transistor 47a, the capacitance element 52, and the resistance element RL1. One of the source and drain of the capacitor 41 is connected to the terminal VBI1 and one electrode of the capacitance element 52. The other electrode of the capacitor element 52 is electrically connected to the wiring VS1. The other of the source and drain of the transistor 41 is connected to one terminal of a resistor element RL1. , one of the source and drain of the transistor 47a, and the gate of the transistor 47a. , and the gate of the transistor 41 is electrically connected to the terminal SH1. The other terminal of the resistor element RL1 is electrically connected to the wiring VD1. The other of the source and drain of transistor 47a is connected to the source and drain of transistor 46a. The other of the source and drain of the transistor 46a is electrically connected to the wiring V The gate of the transistor 46a is electrically connected to the terminal EN1. will be done.

[0072] A transistor may be used as the resistance element. The resistance element may also be a current source. For example, instead of the resistance element, a current generating circuit may be connected and a current may be supplied from the circuit. stomach.

[0073] The circuit 32 shown in FIG. 3B includes a transistor 41, a transistor 46a, and a transistor The circuit 32 shown in FIG. 3B includes a transistor 47a, a capacitance element 52, and a resistance element RL1. The terminal VBI1, rather than one of the source and drain of the transistor 41, 3A in that it is electrically connected to the gate of 47a.

[0074] The circuit 32 shown in FIG. 3C includes a transistor 41, a transistor 46b, and a transistor 3C, the transistor 47b has a capacitance element 52 and a resistance element RL1. One of the source and drain of the capacitor 41 is connected to the terminal VBI1 and one electrode of the capacitance element 52. The other electrode of the capacitor element 52 is electrically connected to the wiring VS1. The other of the source and drain of the transistor 41 is connected to the source and drain of the transistor 47b. and one of the drains of the transistor 46b, the gate of the transistor 46b, and the source and drain of the transistor 46b. The gate of the transistor 41 is electrically connected to one of the terminals S The other of the source and drain of the transistor 46b is electrically connected to the wiring The other of the source and drain of the transistor 47b is electrically connected to VS1. The other terminal of the resistor element RL1 is connected to the wiring VD1. The gate of the transistor 47b is electrically connected to the terminal EN1.

[0075] The circuit 32 shown in FIG. 3D includes a transistor 41, a transistor 46b, and a transistor The circuit 32 shown in FIG. 3D includes a transistor 47b, a capacitance element 52, and a resistance element RL1. The terminal VBI1, rather than one of the source and drain of the transistor 41, 3A, 3B, and 3C in that the gate of the transistor 46b is electrically connected to the gate of the transistor 46a. In FIG. 3C and FIG. 3D, the back gate of the transistor 41 is electrically connected to the wiring VS1. However, the back gate of the transistor 41 has a potential different from that of the wiring VS1. Alternatively, the back gate of the transistor 41 may be electrically connected to the output terminal. may be electrically connected to one of the source and drain of transistor 41. The back gate of a transistor is a pair of gate electrodes sandwiching a gate insulator and a semiconductor layer. The power supply may be electrically connected to the power supply.

[0076] The transistor 41 is a transistor having an oxide semiconductor in a channel formation region (hereinafter referred to as By using an OS transistor, the off-state current can be reduced significantly. After the transistor 41 is turned on and a suitable potential is applied to the terminal VBI1, By turning off the transistor 41, the transistor is brought into a floating state, and the applied potential is maintained. This allows the potential to be programmed to the node ND2.

[0077] The OS transistor will be described in detail later.

[0078] Apply a potential to the terminal SH1 to turn on the transistor 41. Then, a desired potential is applied to the terminal VBI1 as the signal Sv1. A potential that turns off the transistor is applied to the terminal VB The potential of I1 is maintained. The potential applied from the terminal VBI1 is maintained for a long time, preferably for one minute or more, more preferably for one hour. The temperature can be maintained for at least 10 hours, more preferably for at least 10 hours.

[0079] Then, the transistor 46a or the transistor 46b is turned off at the terminal EN1. A potential is applied between the wiring VD1 and the wiring VS1 via the resistor element RL1 in the circuit 32. By cutting off the current, the power consumption of the circuit 32 can be reduced. The force can be significantly reduced.

[0080] At least one of the transistors 46a and 46b is an OS transistor. More specifically, for example, the transistor 46a and the transistor Among the transistors 46b, the terminal EN1 is electrically connected to the gate of the transistor OS By using a transistor, a current flows between the wiring VD1 and the wiring VS1 in the circuit 32. When cutting off a current, the leakage current can be made extremely low.

[0081] In addition, a voltage at the terminal EN1 turns off the transistor 46a or the transistor 46b. After providing the position, each circuit that provides a signal, power, current, etc. to the circuit 32, such as a control circuit, a power supply, The circuit, current generating circuit, voltage generating circuit, current source, constant current source, etc. may be turned off. By turning off these circuits, power consumption can be reduced.

[0082] Furthermore, the oscillator 30, the circuit 31, and the circuit 32 included in the semiconductor device shown in FIG. All the transistors may be OS transistors. All the transistors in the circuit 30, the circuit 31 and the circuit 32 are of the same polarity, for example, n-channel. For example, all the transistors can be n-channel. The semiconductor device can be configured with OS transistors.

[0083] A transistor having silicon in the channel formation region (hereinafter referred to as a Si transistor) The OS transistor may be stacked on the layer having the oscillator 30. By using OS transistors for all of the transistors in the circuit 31 and the circuit 32, On a circuit configured using Si transistors, an oscillator 30, a circuit 31, and a circuit 32 are The circuit area can be reduced by stacking the elements.

[0084] In addition, oxide semiconductors used in OS transistors are grown by thin film deposition methods such as sputtering. Therefore, it can be easily formed on various substrates including glass substrates. This may allow semiconductor devices to be manufactured at low cost.

[0085] 4A shows a configuration example of the circuit 31. The circuit 31 shown in FIG. 4A includes a transistor 61 and a , a transistor 62, and a circuit 63. The gate of the transistor 61 is connected to a terminal VB One of the source and drain of the transistor 61 is electrically connected to the transistor I1. The other is electrically connected to the wiring VS1. The other of the source and drain of the transistor 62 is connected to the circuit 63, a terminal OU3, and The gate of the transistor 62 is electrically connected to the terminal IN2. .

[0086] In FIG. 4A, the transistor 61 and the transistor 62 have back gates. The back gate of each transistor is connected to the source or drain of the respective transistor. is electrically connected to

[0087] FIG. 4B shows a configuration example of the circuit 31. The circuit 31 shown in FIG. 4B is the same as the circuit 3 shown in FIG. In addition to the configuration of 1, a transistor 64, a transistor 65, and a capacitor 66 are included. The gate of the transistor 61 is electrically connected to the terminal VBI1. One of the source and drain is connected to one of the source and drain of transistor 62, and the other are electrically connected to the wiring VS1. The other terminal is connected to the circuit 63, one electrode of the capacitor 66, the gate of the transistor 65, and The other electrode of the capacitor 66 is electrically connected to the source and one of the drains of the transistor 65, one of the source and drain of the transistor 66, and the terminal OU3; The gate of the transistor 62 and the gate of the transistor 64 are electrically connected to The other of the source and drain of the transistor 64 is electrically connected to the terminal IN1. , and the other of the source and drain of the transistor 65 is electrically connected to the wiring VS1. It is electrically connected to the wiring VD1.

[0088] In FIG. 4B, transistor 64 and transistor 65 each have a back gate. The back gate of the transistor 64 is electrically connected to, for example, the wiring VS1. The back gate of the transistor 65 is electrically connected to the terminal OU3, for example.

[0089] 4C, 4D, and 4E each show an example of the circuit 63.

[0090] The circuit 63 shown in FIG. 4C includes a transistor 63a. One of the drains is electrically connected to the gate of the transistor 63a and the wiring VD1. , the other is electrically connected to the other of the source and drain of the transistor 62 .

[0091] The circuit 63 shown in FIG. 4D includes a transistor 63a and a transistor 63b, and a wiring V D1 is electrically connected to one of the source and drain of the transistor 63a and the gate. The other of the source and drain of the transistor 63a is connected to the source of the transistor 63b. the source and drain of the transistor 63b and the gate. The other of the source and drain is electrically connected to the other of the source and drain of transistor 62. is connected to.

[0092] As shown in FIG. 4E, the circuit 63 includes n transistors (n is an integer of 2 or more). The wiring VD1 is connected to the first transistor (transistor 63 in FIG. 4E). a) electrically connected to one of the source and drain of the first transistor and the gate; The other of the source and drain of the second transistor (transistor 63b) and the gate, and In turn, the other of the source and drain of the transistor is connected to the source and drain of the next transistor. The n-th transistor (see FIG. 4E) is electrically connected to one of the drains and the gate. In this case, the other of the source and drain of the transistor 63n is connected to the source of the transistor 62. The source and drain are electrically connected to each other.

[0093] The transistors shown in FIGS. 4C, 4D, and 4E have back gates. The back gates of these transistors are electrically connected to the source or drain of the transistor. do.

[0094] FIG. 5 is a timing chart illustrating an example of the operation of the oscillator 30. In FIG.

[0095] Here, transistor 54, transistor 55, transistor 44 and transistor The threshold voltage of 45 is the potential Vt. The threshold voltage of these transistors is Although there may be variations, for the sake of simplicity, we will use the threshold voltages of these transistors. Assume the values ​​are the same.

[0096] In the oscillator 30, at a certain time, the transistors 44 and 45 An example of the operation of oscillator 30 when one is on and the other is off Here, as an example, at time t0, transistor 44 is in the ON state, and transistor Consider the case where the inverter 45 is in the OFF state.

[0097] At time t0, the transistor 45 is in an off state, and the potential of the node ND4 is, for example, , a potential lower than the potential VD1 by the threshold value of the transistor 55, that is, a potential (VD1-Vt )

[0098] At time t0, transistor 44 is in an on state, and nodes ND1 and ND3 The potentials of the nodes ND1 and ND3 at time t0 are approximately equal. The potential V0 is set to a potential VD1-Vt that is at least higher than the potential (VD1-Vt) of the transistor 44. The value is lower by the threshold, for example, potential (VD1-2Vt).

[0099] The transistor 45 is in an off state, and the charge of the capacitance element 51 is transferred to the transistor 43 and the like. Due to this, the potential of the node ND2 gradually decreases over time.

[0100] At time t1, the potential of the node ND2 is changed from the potential of the node ND3 to the potential of the transistor 45 When the potential drops below the threshold voltage, that is, below the potential (V0-Vt), the transistor 45 turns on. It will be in ON state.

[0101] When the transistor 45 is turned on and becomes conductive, the potential of the node ND4 decreases. In the transistor 44, the potential of the gate relative to the source (Vgs) is equal to or lower than the potential Vt. (Vgs≦Vt), and transistor 44 is turned off.

[0102] When the transistor 44 is turned off, the potential of the node ND3 changes from the potential VD1 to The potential rises to a potential lower by the threshold value of the transistor 54, that is, to a potential (VD1-Vt). The potential of the node ND1 also rises together with the node ND3. As a result, the potential of the node ND1 gradually decreases over time.

[0103] At time t2, the potential of the node ND1 changes from the potential of the node ND4 to the potential of the transistor 44 When the potential drops below the threshold voltage, the transistor 44 is turned on. When transistor 4 is turned on, the potentials of nodes ND1 and ND3 become the potential V0. The transistor 45 is turned off, and the potential of the node ND4 rises to the potential (VD1-Vt). The potential of the node ND2 also rises together with the node ND4, but decreases with time.

[0104] The potential of the node ND4 is VD1-Vt between time t0 and time t1, and Between time t1 and time t2, the potential is V0, and thereafter, the potential is alternately VD1-Vt and the potential V0. It functions as an oscillator by repeating the same process. The length of time from time t1 to time t2 depends on the capacitance value of the capacitance element 51, the transistor The magnitude of the current flowing through transistor 42 and transistor 43, transistor 54, The threshold voltage of the transistor 55, the transistor 44 and the transistor 45, etc.

[0105] 6A shows a configuration example of a semiconductor device 21. The semiconductor device 21 shown in FIG. In addition to the components shown, the oscillator 30 includes an amplifier circuit 36. The amplifier circuit 36 ​​is connected to a terminal OU of the oscillator 30. The amplifier circuit 36 ​​receives the signals output from terminals OU1 and OU2. An amplified signal is generated based on the signals given from the terminals OU1 and OU2, and is output to the terminals of the circuit 31. It has the function of giving IN2.

[0106] In addition, in the configuration of the semiconductor device 21 shown in FIGS. 1, 2, 6A, etc., 6B shows a configuration in which the output circuit 31 in FIG. 6A is configured in two stages. This is an example of a configuration in which the electrodes are used in layers.

[0107] 7A and 7B show an example of the amplifier circuit 36. FIG.

[0108] The amplifier circuit 36 ​​shown in FIG. 7A includes a transistor 71, a transistor 72, and a transistor 73. 3, has a circuit 63x and a circuit 63y. As the circuit 63x and the circuit 63y, , a circuit such as the circuit 63 shown in FIGS. 4D and 4E can be used.

[0109] In FIG. 7A, the circuit 63x includes a wiring VD1 and a source and a drain of a transistor 72. The circuit 63y is disposed between the wiring V D1 and one of the source and drain of the transistor 73, One of the source and drain of the transistor 73 is electrically connected to the terminal IN2 The gate of transistor 72 is electrically connected to terminal OU1. The gate of transistor 73 is electrically connected to terminal OU2. the gate of the transistor 72, the other of the source and drain of the transistor 73, The gate of the transistor 73 and the other of the source and drain of the transistor 71 The source and drain of the transistor 71 are electrically connected to one of the source and drain of the transistor 72. The other drain and the back gate are electrically connected to a wiring VS1. The gate of 71 is electrically connected to the terminal VBI1 of the circuit 32.

[0110] The amplifier circuit 36 ​​shown in FIG. 7A receives a signal supplied to a terminal OU1 and a signal supplied to a terminal OU2. It has the function of amplifying the difference between signals.

[0111] The amplifier circuit 36 ​​shown in FIG. 7B includes, in addition to the components shown in FIG. 7A, a transistor 74, a transistor It has a transistor 75, a transistor 76 and a transistor 77.

[0112] In FIG. 7A, one of the source and drain of transistor 73 is electrically connected to terminal IN2. , but in FIG. 7B is electrically connected to the gate of transistor 77. 7B, one of the source and drain of the transistor 72 and the circuit 63x , is electrically connected to the gate of transistor 76.

[0113] One of the source and the drain of the transistor 76 is electrically connected to the wiring VD1. The other is connected to one of the source and drain of the transistor 74 and the gate of the transistor 74. , and the gate of transistor 75. The source and The other of the drains is electrically connected to the back gate of the transistor 74 and the wiring VS1. To be continued.

[0114] One of the source and drain of the transistor 77 is connected to the wiring VD1, and the other is connected to the The transistor 75 is electrically connected to one of the source and drain terminals and to the terminal IN2. The other of the source and drain of the transistor 75 is connected to the back gate of the transistor 75 and the wiring VS1 and VS2.

[0115] The semiconductor device 21 includes the amplifier circuit 36 ​​and the circuit 31 described above, and therefore, oscillation The amplifier 30 can amplify and shape the signal at the desired frequency, preferably A high output signal can be obtained.

[0116] FIG. 8A illustrates an example in which the semiconductor device of one embodiment of the present invention is applied to a secondary battery. The semiconductor device of this embodiment can be connected to a secondary battery to form a power storage device.

[0117] FIG. 8A shows a secondary battery 121 and a semiconductor device 21 electrically connected to the secondary battery 121. The semiconductor device 21 shown in FIG. 8A includes a circuit 33, a transistor 49, and a circuit 3 2, an oscillator 30, and a circuit 31.

[0118] The circuit 33 includes a comparator 56 , a transistor 48 , and a capacitor 57 . The comparator 56 compares the reference potential with the positive electrode potential of the secondary battery 121, and outputs the result of the comparison. In the example shown in FIG. 8A, the positive electrode of the secondary battery 121 is The inverting input terminal of the comparator 56 is electrically connected to the non-inverting input terminal of the comparator 56. In the example shown in FIG. 8A, the reference potential is applied to the inverting input terminal, and the reference potential is applied to the The potential to be compared with the reference potential is given to the non-inverting input terminal. A potential for comparison may be applied to the input terminal and the inverting input terminal, respectively.

[0119] The reference potential given to the comparator 56 is supplied from the terminal VT1 through the transistor 48. It is preferable to use an OS transistor as the transistor 48. For example, A high potential signal is applied from terminal SH2 to the gate of transistor 48 to turn on transistor 48. After applying a suitable potential to the inverting input terminal of the comparator 56, a trigger is output from the terminal SH2. By applying a low potential signal to the gate of transistor 48, transistor 48 is turned off. By keeping the potential at a given level, the inverting input terminal of the comparator 56 The potential can be programmed to

[0120] The output terminal of the comparator 56 (called terminal OU4) supplies a voltage to the gate of the transistor 49. One of the source and drain of transistor 49 (terminal S in FIG. 8A) is electrically connected. G1) is electrically connected to the wiring VS1, and the other is connected to the circuit 32, the oscillator 30 and the circuit The transistor 49 is electrically connected to the respective circuits, the wiring VS1, and The transistor has a function of controlling whether the transistor is electrically connected or disconnected. The transistor 49 is, for example, a transistor 42 and a transistor 43 of the oscillator 30 shown in FIG. , the transistor 61 of the circuit 31, the transistor 46a of the circuit 32 shown in FIG. 3A, etc., and FIG. 3C , etc. of the circuit 32 shown in FIG.

[0121] By providing the circuit 33 with a reference potential for controlling or protecting the secondary battery 121, As a result, the semiconductor device 21 is operated as a circuit for controlling or protecting the secondary battery 121. In the following, a potential for detecting overcharge is applied to the circuit 33 as a reference potential. An example will be described with reference to the timing chart shown in FIG. The sum of the currents flowing through the circuit 31 and the circuit 32 is taken as current ID1.

[0122] At time t11, the potential of the terminal OU4 is a low potential signal. The terminal SG1 is in a floating state. be.

[0123] At time t12, when the positive electrode potential of the secondary battery 121 exceeds the reference potential, that is, when the secondary battery If the battery 121 is determined to be in an overcharged state, the comparator 56 outputs a high potential signal from the terminal OU4. A high potential signal is sent from comparator 56 to the gate of transistor 49, Transistor 49 is turned on.

[0124] When the transistor 49 is turned on, the line VS1, the circuit 32, the oscillator 30 and the circuit The line 31 is in a conductive state, and the potential of the wiring VS1 (in the example shown in FIG. 8B) is applied to the terminal SG1. signal) is given, and a potential is given to each circuit from the wiring VS1 via the terminal SG1, and the circuit 32, the oscillator 30, the circuit 31 and the wiring VS1 are brought into a conductive state.

[0125] At time t13, a signal is applied to the terminal EN1, and in the circuit 32, the transistors 46a and 46b are turned on. Also, a signal is given to the terminal SH1, and the transistor 47a is turned on. The resistor 41 is turned on, and the potential VBI1 is applied to the oscillator 30 from the terminal VBI1. Then, a signal of the desired frequency is output from terminal OU3.

[0126] At time t14, a signal is applied to the terminal SH1, and the transistor 41 is turned off. The potential output from the terminal VBI1 is maintained at a constant value.

[0127] At time t15, a signal is applied to the terminal EN1, and the transistor 46a or the transistor 4 A potential that turns off the gate of the transistor 7a is applied to the transistor 7b. The current flowing through the circuit 32 is cut off, and the Flow ID1 becomes lower.

[0128] At time t16, a low potential signal is output from the terminal OU4, and the circuit 32, the oscillator 30, and the circuit The current flowing through 31 is cut off, and terminal SG1 is left floating.

[0129] For example, the signal from terminal OU3 is sent to a circuit that controls the charging of the secondary battery to stop the charging. or change the charging conditions to protect or control the secondary battery. By controlling a secondary battery using a semiconductor device of one embodiment of the present invention, The power storage device of one embodiment of the present invention can be configured with low power consumption. The current can improve the safety of the secondary battery and also increase the life of the secondary battery. In addition, there are cases where the capacity of secondary batteries can be improved while maintaining a high level of safety. There is a match.

[0130] When the transistor 49 is in the off state, the wiring VS1 and the circuit 32, the oscillator 30 and the circuit Since the current of 31 is cut off, the power consumption of each circuit can be significantly reduced. By using an OS transistor as the transistor 49, the off state of the transistor 49 This allows for extremely small leakage current in the ON state, thereby reducing power consumption to the minimum. This can be done.

[0131] In addition, for example, in the case of over-discharge detection, the non-inverting input terminal is set to the criterion for determining the over-discharge state. A potential may be applied to the inverting input terminal, and the positive electrode potential of the secondary battery may be applied to the inverting input terminal. When the positive electrode potential of the battery becomes lower than the reference potential, a high potential signal is output from the comparator.

[0132] A semiconductor device according to one embodiment of the present invention includes, for example, a circuit having a function of controlling a battery. A circuit having a function of controlling a battery may be mounted on the semiconductor device of one embodiment of the present invention. By connecting the power supply to a secondary battery, a power storage device can be configured. 8, the control circuit 38 is included as a circuit having the function. is applied to the control circuit 38. The control circuit 38 also supplies the terminals SH1, EN1, VT1, SH 2, etc., and provide them to each circuit. Alternatively, a circuit for generating these signals may be provided. A control signal may be provided to

[0133] The control circuit 38 includes, for example, a circuit having a function of changing the conditions for charging or discharging the battery. The conditions may be, for example, current density, upper limit voltage, lower limit voltage, mode switching, etc. , etc. Examples of modes include a constant current mode, a constant voltage mode, etc. The semiconductor device of one embodiment of the present invention has a function of protecting a battery, for example. For example, when an overcharge is detected, the battery is discharged. For example, it can detect battery abnormalities and stop battery operation, or Stopping the operation of the battery means, for example, stopping charging or discharging. Battery abnormalities include overcharging, over-discharging, overcurrent during charging, and overcurrent during discharging. Overcurrent, short circuit, micro-short circuit (described later), deviation from the specified operating temperature range, etc. Examples include:

[0134] The control circuit 38 can be configured using, for example, Si transistors. The control circuit 38 may be configured using OS transistors and Si transistors. Alternatively, control circuit 38 may be formed using OS transistors.

[0135] The semiconductor device of one embodiment of the present invention can be used for a temperature sensor, a pressure sensor, an illuminance sensor, a motor sensor, or the like. The semiconductor device according to one embodiment of the present invention may include a sensor, an optical sensor, a humidity sensor, or the like. has a function of controlling the battery according to the detection results of these sensors, for example.

[0136] (Embodiment 2) In this embodiment mode, an OS An example of the transistor configuration is described below. Note that an OS transistor is a thin film transistor. In this embodiment, the semiconductor device is formed on a single crystal silicon substrate. 10A and 10B are structural examples of a semiconductor device in which an OS transistor is provided above a Si transistor. I will explain.

[0137] <Configuration example of semiconductor device> The semiconductor device shown in FIG. 9 includes a transistor 300, a transistor 500, and a capacitor. 10A is a cross-sectional view of the transistor 500 in the channel length direction. 10B is a cross-sectional view of the transistor 500 in the channel width direction, and FIG. 10C is a cross-sectional view of the transistor 500 in the channel width direction. FIG. 3 is a cross-sectional view of the star 300 in the channel width direction.

[0138] The transistor 500 is an OS transistor in the channel formation region. 00 has the feature of having a very small off-state current.

[0139] The semiconductor device described in this embodiment includes, as shown in FIG. The transistor 500 includes a transistor 3. 00, and the capacitance element 600 is provided above the transistor 300 and the transistor 50 It is located above 0.

[0140] The transistor 300 is disposed on a substrate 311, and includes a conductor 316, an insulator 315, and a substrate A semiconductor region 313 consisting of a part of 311 and functioning as a source region or a drain region. The semiconductor device has a low resistance region 314a that functions as a dielectric film, and a low resistance region 314b.

[0141] Transistor 300 includes a top surface and a channel of semiconductor region 313, as shown in FIG. 10C. The side surfaces in the width direction of the transistor are covered with a conductor 316 via an insulator 315. By making the transistor 300 a fin type, the effective channel width increases, This can improve the on-state characteristics of the transistor 300. Since the applied current can be increased, the off-characteristics of the transistor 300 can be improved. do.

[0142] The transistor 300 may be either a p-channel type or an n-channel type. .

[0143] The region where the channel of the semiconductor region 313 is formed, the region in the vicinity thereof, the source region, or In the low resistance region 314a which becomes the drain region and the low resistance region 314b, silicon It preferably contains a semiconductor such as a silicon-based semiconductor, and it preferably contains single crystal silicon. Or Ge (germanium), SiGe (silicon germanium), GaAs (gallium It may be made of materials containing gallium aluminum arsenide (GaAlAs) or GaAlAs (Gallium Aluminum Arsenide). Silicon with effective mass controlled by applying stress to the crystal lattice and changing the lattice spacing. Alternatively, GaAs and GaAlAs may be used to form a transistor. The Star 300 is a HEMT (High Electron Mobility Transistor) stor) can also be used.

[0144] The low resistance region 314a and the low resistance region 314b are formed by the semiconductor layer applied to the semiconductor region 313. In addition to the conductive material, elements that impart n-type conductivity, such as arsenic and phosphorus, or p-type conductivity, such as boron, are added. It contains elements that impart electrical conductivity to the material.

[0145] The conductor 316, which functions as a gate electrode, is made of arsenic, phosphorus, or the like, which provides n-type conductivity. Semiconductor materials such as silicon that contain elements or elements that give them p-type conductivity, such as boron Conductive materials such as aluminum, metal, alloy, or metal oxide materials can be used. .

[0146] In addition, since the work function is determined by the material of the conductor, by changing the material of the conductor, The Vth of the transistor can be adjusted. Specifically, titanium nitride or nitride is used as the conductor. It is preferable to use a material such as tantalum. It is preferable to use a metal material such as tungsten or aluminum as a laminated conductor. In particular, tungsten is preferred in terms of heat resistance.

[0147] The transistor 300 shown in FIG. 9 is an example, and the structure is not limited to this. An appropriate transistor may be used depending on the type and driving method.

[0148] Over the transistor 300 are insulators 320, 322, 324, and The edge members 326 are stacked in order.

[0149] The insulators 320, 322, 324, and 326 may be, for example, an acid. silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, Aluminum oxynitride, aluminum nitride oxide, aluminum nitride, or the like may be used.

[0150] The insulator 322 serves to eliminate a step caused by the transistor 300 and other components disposed below it. For example, the top surface of the insulator 322 may have a function as a planarizing film. To improve flatness, the surface is flattened by a planarization process using chemical mechanical polishing (CMP) or other methods. It may be possible.

[0151] The insulator 324 is also provided with a substrate 311 or a transistor 300 or the like. A film having a barrier property to prevent diffusion of hydrogen and impurities is formed in the area where the star 500 is provided. It is preferable to use

[0152] An example of a film having a barrier property against hydrogen is silicon nitride formed by CVD. Here, a semiconductor having an oxide semiconductor such as the transistor 500 can be used. The diffusion of hydrogen into semiconductor elements can cause a deterioration in the characteristics of the semiconductor elements. Therefore, a film that suppresses hydrogen diffusion is provided between the transistor 500 and the transistor 300. Specifically, the film that suppresses the diffusion of hydrogen is a film that reduces the amount of hydrogen desorption. The membrane is thin.

[0153] The amount of desorbed hydrogen can be analyzed using, for example, temperature programmed desorption spectroscopy (TDS analysis). For example, the amount of hydrogen desorbed from the insulator 324 can be determined by the TDS analysis. In the temperature range of 50 to 500°C, the amount of desorption converted to hydrogen atoms is Converted to per area, it is 10 x 10 15 atoms / cm 2 Less than or equal to 5 x 10 1 5 atoms / cm 2 The following is fine.

[0154] It is preferable that the insulator 326 has a lower dielectric constant than the insulator 324. For example, The dielectric constant of the insulator 326 is preferably less than 4, more preferably less than 3. The relative dielectric constant of the insulator 326 is preferably 0.7 times or less than the relative dielectric constant of the insulator 324, and more preferably 0.6 times or less. By using a material with a low relative dielectric constant as the interlayer film, the parasitic capacitance generated between wirings can be reduced. can be reduced.

[0155] In addition, the insulators 320, 322, 324, and 326 are provided with capacitive elements. 600, or the conductor 328 and the conductor 330 connected to the transistor 500 are buried. The conductors 328 and 330 are plugs or wires. In addition, the conductor having the function of a plug or wiring has a plurality of structures. In addition, in this specification and the like, the wiring and the wiring The conductor and the plug to be connected may be an integral part. In some cases, a part of the conductor functions as a plug.

[0156] The materials for each plug and wiring (conductor 328, conductor 330, etc.) are metal. Conductive materials such as metals, alloy materials, metal nitride materials, or metal oxide materials are applied as single layers or Materials such as tungsten and molybdenum, which have both heat resistance and electrical conductivity, can be used. It is preferable to use any high melting point material, and it is preferable to use tungsten. It is preferable to form the conductive layer from a low-resistance conductive material such as aluminum or copper. By using this material, the wiring resistance can be reduced.

[0157] A wiring layer may be provided on the insulator 326 and the conductor 330. For example, in FIG. An insulator 350, an insulator 352, and an insulator 354 are stacked in this order. In addition, a conductor 356 is formed in the insulators 350, 352, and 354. The conductor 356 functions as a plug or wiring that connects to the transistor 300. The conductor 356 is made of the same material as the conductors 328 and 330. It can be established as follows.

[0158] For example, the insulator 350 has a barrier property against hydrogen, similar to the insulator 324. It is preferable to use an insulator having a barrier property against hydrogen. It is preferable that the insulating material 350 has a barrier property against hydrogen. A conductor having a barrier property against hydrogen is formed in the opening. The transistor 300 and the transistor 500 can be separated by a barrier layer. The diffusion of hydrogen from the transistor 300 to the transistor 500 can be suppressed.

[0159] As a conductor having a barrier property against hydrogen, for example, tantalum nitride or the like is used. In addition, by laminating tantalum nitride and highly conductive tungsten, The diffusion of hydrogen from the transistor 300 can be suppressed while maintaining the overall conductivity. In this case, the tantalum nitride layer having a barrier property against hydrogen is It is preferable that the insulating body 350 has a structure in which the insulating body 350 is in contact with the insulating body 350.

[0160] A wiring layer may be provided on the insulator 354 and the conductor 356. For example, in FIG. An insulator 360, an insulator 362, and an insulator 364 are stacked in this order. In addition, a conductor 366 is formed in the insulators 360, 362, and 364. The conductor 366 functions as a plug or wiring. , conductor 328, and conductor 330 can be formed using the same materials.

[0161] For example, the insulator 360 has a barrier property against hydrogen, similar to the insulator 324. It is preferable to use an insulator having a barrier property against hydrogen. It is preferable that the insulating material 360 has a barrier property against hydrogen. A conductor having a barrier property against hydrogen is formed in the opening. The transistor 300 and the transistor 500 can be separated by a barrier layer. The diffusion of hydrogen from the transistor 300 to the transistor 500 can be suppressed.

[0162] A wiring layer may be provided on the insulator 364 and the conductor 366. For example, in FIG. An insulator 370, an insulator 372, and an insulator 374 are stacked in this order. In addition, a conductor 376 is formed in the insulators 370, 372, and 374. The conductor 376 functions as a plug or wiring. , conductor 328, and conductor 330 can be formed using the same materials.

[0163] For example, the insulator 370 has a barrier property against hydrogen, similar to the insulator 324. It is preferable to use an insulator having a barrier property against hydrogen. In particular, an insulator 370 having a barrier property against hydrogen is useful. A conductor having a barrier property against hydrogen is formed in the opening. The transistor 300 and the transistor 500 can be separated by a barrier layer. The diffusion of hydrogen from the transistor 300 to the transistor 500 can be suppressed.

[0164] A wiring layer may be provided on the insulator 374 and the conductor 376. For example, in FIG. An insulator 380, an insulator 382, ​​and an insulator 384 are stacked in this order. In addition, a conductor 386 is formed in the insulators 380, 382, ​​and 384. The conductor 386 functions as a plug or wiring. , conductor 328, and conductor 330 can be formed using the same materials.

[0165] For example, the insulator 380 has a barrier property against hydrogen, similar to the insulator 324. It is preferable to use an insulator having a barrier property against hydrogen. It is preferable that the insulator 380 has a barrier property against hydrogen. A conductor having a barrier property against hydrogen is formed in the opening. The transistor 300 and the transistor 500 can be separated by a barrier layer. The diffusion of hydrogen from the transistor 300 to the transistor 500 can be suppressed.

[0166] In the above, the wiring layer including the conductor 356, the wiring layer including the conductor 366, the conductor 376 The wiring layer including the conductor 386 has been described. The semiconductor device is not limited to this. The number of layers may be three or less, or five or more wiring layers similar to the wiring layer including the conductor 356. That's fine.

[0167] On the insulator 384 are an insulator 510, an insulator 512, an insulator 514, and an insulator 516. are stacked in this order. It is preferable that the insulator 516 is made of a material that has a barrier property against oxygen and hydrogen. It's nice.

[0168] For example, the insulator 510 and the insulator 514 may include the substrate 311 or the transistor 312. Hydrogen and impurities diffuse from the region where the transistor 500 is provided to the region where the transistor 500 is provided. Therefore, it is preferable to use a film having a barrier property that does not cause the insulator 324 to be broken down. Various materials can be used.

[0169] As an example of a film with barrier properties against hydrogen, silicon nitride formed by CVD is used. Here, a semiconductor element including an oxide semiconductor, such as the transistor 500, However, the diffusion of hydrogen may deteriorate the characteristics of the semiconductor element. A film that suppresses hydrogen diffusion is used between the transistor 500 and the transistor 300. Specifically, the film that suppresses hydrogen diffusion is a film that releases a small amount of hydrogen. do.

[0170] In addition, as a film having a barrier property against hydrogen, for example, an insulator 510 and an insulator 514 uses metal oxides such as aluminum oxide, hafnium oxide, and tantalum oxide. It is preferable that

[0171] In particular, aluminum oxide is highly resistant to oxygen and water, which can cause fluctuations in the electrical characteristics of transistors. It has a high blocking effect that prevents impurities such as oxygen and moisture from penetrating the membrane. Aluminum oxide is a material that can withstand hydrogen, moisture, and other chemicals during and after the transistor manufacturing process. This can prevent impurities from entering the transistor 500. This can suppress the release of oxygen from the oxide that makes up the transistor. It is suitable for use as a protective film for the substrate 500.

[0172] For example, the insulators 512 and 516 may be made of the same material as the insulator 320. In addition, by using a material with a relatively low dielectric constant as the interlayer film, the For example, the insulators 512 and 516 may be formed of For example, a silicon oxide film or a silicon oxynitride film can be used.

[0173] In addition, the insulators 510, 512, 514, and 516 are made of conductive materials. 518, and the conductor (conductor 503) that constitutes the transistor 500 are embedded. Note that the conductor 518 is a capacitor 600 or a transistor connected to the transistor 300. The conductor 518 functions as a lug or wiring. It can be provided using the same material as 330.

[0174] In particular, the insulator 510 and the conductor 518 in the region in contact with the insulator 514 are oxidized to oxygen, hydrogen, and It is preferable that the conductive material has a barrier property against water. The transistor 300 and the transistor 500 have barrier properties against oxygen, hydrogen, and water. The layer having the hydrogen atoms can be separated from the transistor 300 to the transistor 500. The diffusion of can be suppressed.

[0175] Above the insulator 516 is the transistor 500 .

[0176] In FIG. 9, a conductor 610 of a capacitor element 600 is provided in an opening of an insulator 580 or the like. One of the source and drain of the transistor 500 is connected to the transistor 501 via a conductor. The gate of transistor 300 is connected to the gate of transistor 500. Another transistor is provided, and the conductor 610 is provided in the opening of the insulator 580, etc. The gate of the OS transistor may be connected to the body of the OS transistor.

[0177] As shown in FIGS. 10A and 10B, the transistor 500 includes an insulator 514 and an insulator The conductor 503 is disposed so as to be embedded in the insulator 516, and the insulator 516 and the conductor 503 are disposed so as to be embedded in the insulator 516. an insulator 520 disposed on the insulator 520; an insulator 522 disposed on the insulator 520; An insulator 524 is disposed on the insulating layer 522, and an oxide 530a is disposed on the insulating layer 524. and oxide 530b disposed on oxide 530a, and oxide 530b disposed on oxide 530b, separated from each other. The conductor 542a and the conductor 542b are arranged in parallel. 542b, and an opening is formed between and overlapping the conductors 542a and 542b. The insulating material 580 is disposed in the opening, the conductor 560 is disposed in the opening, and the oxide 530b and the conductor 54 are disposed in the opening. 2a, conductor 542b, and an insulator disposed between insulator 580 and conductor 560. 550, oxide 530b, conductor 542a, conductor 542b, and insulator 580. , an insulator 550, and an oxide 530c disposed therebetween.

[0178] 10A and 10B, the oxide 530a, the oxide 530b, the conductor 5 42a, and an insulator 544 may be disposed between the conductor 542b and the insulator 580. 10A and 10B, the conductor 560 is preferably formed in the insulator 550. The conductor 560a is provided on the side of the conductor 560a, and the conductor 560b is provided so as to be embedded inside the conductor 560a. 10A and 10B, it is preferable to have a conductor 560b. 5, an insulator 574 is disposed on the insulator 580, the conductor 560, and the insulator 550. It is preferable that:

[0179] In the following, the oxide 530a, the oxide 530b, and the oxide 530c will be collectively referred to as oxide 530a, oxide 530b, and oxide 530c. The conductor 542a and the conductor 542b are sometimes collectively referred to as oxide 530. It may also be referred to as conductor 542.

[0180] In the transistor 500, an oxide is formed in the region where the channel is formed and in the vicinity thereof. 5 shows a structure in which three layers of oxide 530a, oxide 530b, and oxide 530c are stacked. However, the present invention is not limited to this. For example, a single layer of oxide 530b, an oxide Two-layer structure of oxide 530b and oxide 530a, two-layer structure of oxide 530b and oxide 530c Alternatively, a stacked structure of four or more layers may be provided. Although the conductor 560 is shown as a two-layer laminate structure, the present invention is not limited to this. For example, the conductor 560 may have a single layer structure or a laminated structure of three or more layers. The transistor 500 shown in FIGS. 9, 10A, and 10B is an example. The present invention is not limited to the above structure, and an appropriate transistor may be used depending on the circuit configuration and driving method.

[0181] Here, the conductor 560 functions as the gate electrode of the transistor, and the conductors 542a and and the conductor 542b function as a source electrode and a drain electrode, respectively. Thus, conductor 560 is inserted through the opening in insulator 580 and through conductors 542a and 542b. The conductor 560, the conductor 542a, and the conductor 542b are formed so as to be embedded in the region sandwiched between them. The placement of the conductor 542b is selected to be self-aligned with the opening of the insulator 580. In the transistor 500, the gate electrode is disposed between the source electrode and the drain electrode. Therefore, the conductor 560 can be arranged in a self-aligned manner without providing a margin for alignment. Since the transistor 500 can be formed without any gaps, the area occupied by the transistor 500 can be reduced. This allows for miniaturization and high integration of semiconductor devices.

[0182] Furthermore, the conductor 560 is self-aligned in the region between the conductors 542a and 542b. Since the conductor 560 is formed, the area where the conductor 560 overlaps with the conductor 542a or the conductor 542b is As a result, the conductor 560 does not have a gap between the conductor 542a and the conductor 542b. The parasitic capacitance formed can be reduced. This improves the scanning speed and provides high frequency characteristics.

[0183] Conductor 560 may function as a first gate (also called top gate) electrode. The conductor 503 functions as a second gate (also called a bottom gate) electrode. In this case, the potential applied to the conductor 503 may be changed to the potential applied to the conductor 560. The Vth of the transistor 500 is controlled by changing it independently of the voltage level. In particular, applying a negative potential to the conductor 503 can turn on the transistor 50 Therefore, it is possible to reduce the off-state current by increasing the Vth of the MOSFET to be larger than 0V. Applying a negative potential to the conductor 503 is more effective than applying a negative potential to the conductor 560. This can reduce the drain current when the applied potential is 0V.

[0184] The conductor 503 is arranged to overlap the oxide 530 and the conductor 560. When a potential is applied to the conductor 560 and the conductor 503, The electric field generated by the conductor 503 is connected to the electric field generated by the conductor 503, and the choke formed in the oxide 530 is generated. In this specification and the like, the first gate electrode and the second gate electrode can cover the channel forming region. The electric field of the gate electrode of the transistor electrically surrounds the channel forming region. This structure is called a surrounded channel (S-channel) structure.

[0185] In this specification and the like, the S-channel structure refers to a structure in which a source electrode and a drain electrode are The side of the oxide 530 in contact with the conductor 542a and the conductor 542b that function as electrodes and The periphery has the I-type structure similar to the channel forming region. 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. Therefore, the I type can be formed in the same manner as the channel formation region. The type can be treated as the same as the high-purity genuine type described later. The S-channel structure is different from the fin structure and the planar structure. By adopting a n-channel structure, the resistance to the short channel effect is increased. This makes it possible to provide a transistor in which the channel effect is less likely to occur.

[0186] The conductor 503 has the same structure as the conductor 518, and the insulator 514 and the insulator Conductor 503a is formed in contact with the inner wall of the opening of 516, and conductor 503b is formed further inside. It is formed.

[0187] The insulators 520, 522, 524, and 550 form a gate insulating film. It has the function of

[0188] Here, the insulator 524 in contact with the oxide 530 has more oxygen than the stoichiometric composition. It is preferable to use an insulator that contains a large amount of oxygen. That is, the insulator 524 has an excess oxygen region. It is preferable that the insulator containing such excess oxygen is formed in the oxide 530. By providing the oxide 530 in contact with the oxide 530, oxygen vacancies in the oxide 530 are reduced, and the signal quality of the transistor 500 is improved. The reliability can be improved.

[0189] As an insulator having an excess oxygen region, specifically, an oxide in which a part of oxygen is released by heating is used. It is preferable to use oxide materials. Oxides that release oxygen when heated are called TDS (Th Thermal Desorption Spectroscopy (DSS) analysis revealed that the oxygen atoms The converted amount of oxygen desorption is 1.0 x 10 18 atoms / cm 3 or more, preferably 1.0 x10 19 atoms / cm 3 More preferably, 2.0 × 10 19 atoms / c m 3 or more, or 3.0 x 10 20 atoms / cm 3 The oxide film is as described above. The surface temperature of the film during the TDS analysis is 100°C or higher and 700°C or lower, or The temperature is preferably in the range of 00°C or higher and 400°C or lower.

[0190] Also, if the insulator 524 has an excess oxygen region, the insulator 522 may be oxygen-rich (e.g., It has the function of suppressing the diffusion of oxygen atoms, oxygen molecules, etc. (the oxygen is less likely to permeate) It is preferable that:

[0191] The insulator 522 has a function of suppressing the diffusion of oxygen and impurities, and the oxide 530 The oxygen contained in the conductor 503 is preferably not diffused to the insulator 520 side. This can prevent the insulator 524 and the oxide 530 from reacting with oxygen.

[0192] The insulator 522 may be, for example, aluminum oxide, hafnium oxide, tantalum oxide, or zinc oxide. lead zirconate titanate (PZT), strontium titanate (SrTiO3 ) or (Ba,Sr)TiO3 (BST), which are so-called high-k materials It is preferable to use the body in a single layer or a multilayer structure. As this progresses, problems such as leakage current may occur due to the thinning of the gate insulating film. By using a high-k material as an insulator that functions as a gate insulating film, This makes it possible to reduce the gate potential during transistor operation.

[0193] In particular, it has the function of suppressing the diffusion of impurities and oxygen (the oxygen is less likely to permeate). a) Insulating materials containing oxides of one or both of aluminum and hafnium It is recommended to use an insulator containing oxides of either or both aluminum and hafnium. The oxides include aluminum oxide, hafnium oxide, aluminum and hafnium. It is preferable to use oxide (hafnium aluminate) or the like. When the insulator 522 is formed by the oxide 530, the insulator 522 is resistant to oxygen release from the oxide 530 and to The layer serves to prevent impurities such as hydrogen from entering the oxide 530 from the periphery of the transistor 500. It works like this.

[0194] Alternatively, for example, aluminum oxide, bismuth oxide, germanium oxide, or the like may be added to these insulators. um, niobium oxide, silicon oxide, titanium oxide, tungsten oxide, yttrium oxide, Zirconium oxide may be added, or these insulators may be nitrided. Silicon oxide, silicon oxynitride or silicon nitride may be laminated on the insulator. .

[0195] The insulator 520 is preferably thermally stable. For example, silicon oxide and Silicon oxide nitride and silicon oxynitride are suitable because they are thermally stable. By combining this insulator with silicon oxide or silicon oxynitride, Furthermore, it is possible to obtain the insulator 520 having a laminated structure with a high relative dielectric constant.

[0196] The insulators 520, 522, and 524 each have a laminated structure of two or more layers. In this case, the laminated structure is not limited to the same material, but may be made of different materials. It may have a laminated structure.

[0197] The transistor 500 includes an oxide 530 including a channel formation region, and an oxide semiconductor It is preferable to use a functional metal oxide. For example, the oxide 530 is In-M- Zn oxide (element M is aluminum, gallium, yttrium, copper, vanadium, beryl Sodium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, la tantalum, tungsten, or magnesium It is preferable to use a metal oxide such as one or more selected from the group consisting of aluminum, etc. The material 530 may be an In-Ga oxide or an In-Zn oxide.

[0198] Furthermore, it is preferable to use a metal oxide with a low carrier concentration for the transistor 500. When the carrier concentration of the metal oxide is reduced, the impurity concentration in the metal oxide is reduced. In this specification and the like, the impurity concentration is low and the defect level density is low. A low level density is called high purity intrinsic or substantially high purity intrinsic. Examples of impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, Examples include silicon and silicon dioxide.

[0199] In particular, hydrogen contained in metal oxides reacts with oxygen that bonds with metal atoms to form water. In this case, oxygen vacancies may be formed in the metal oxide. If an element defect is included, the transistor may have normally-on characteristics. The defect where hydrogen has entered the oxygen vacancy acts as a donor, generating electrons as carriers. In addition, some of the hydrogen atoms may bond with oxygen atoms that bond with metal atoms, forming electron carriers. Therefore, transistors using metal oxides containing a large amount of hydrogen The starter tends to have normally-on characteristics.

[0200] The defect where hydrogen has entered the oxygen vacancy can function as a donor for the metal oxide. However, it is difficult to quantitatively evaluate the defects. Therefore, in this specification, metal As a parameter of the oxide, instead of donor concentration, we use the capacitance assuming a state where no electric field is applied. In other words, the "carrier concentration" described in this specification and the like is This can sometimes be rephrased as "energy concentration."

[0201] Therefore, when a metal oxide is used for the oxide 530, the hydrogen in the metal oxide should be as low as possible. Specifically, in the case of metal oxides, secondary ion mass spectrometry (SIMS: Secondary Ion Mass Spectrometry) The resulting hydrogen concentration is 1×10 20 atoms / cm 3 Less than 1 x 10 19 atoms / cm 3 less than 5 × 10 18 atoms / cm 3 Less than, more Preferably 1 x 10 18 atoms / cm 3 Less than 100%. Impurities such as hydrogen are sufficiently reduced. By using this metal oxide in the channel formation region of a transistor, stable electrical characteristics can be achieved. can be granted.

[0202] In addition, when a metal oxide is used for the oxide 530, the capacitance of the metal oxide in the channel formation region is Rear density is 1 x 10 18 cm -3 Preferably, it is 1×10 or less. 17 cm -3 Not yet It is more preferable that the 16 cm -3 more preferably less than 1×10 13 cm -3 More preferably, it is less than 1×10 12 cm -3 Less than It is more preferable that the lower limit of the carrier concentration of the metal oxide in the channel formation region is There is no particular limitation on the -9 cm -3 It can be said that:

[0203] When a metal oxide is used for the oxide 530, the conductor 542 (the conductor 542a and When the oxide 530 comes into contact with the conductor 542b, the oxygen in the oxide 530 is transferred to the conductor 542. The conductor 542 may be oxidized by the oxidation of the conductor 542. It is highly likely that the conductivity of the conductor 542 will decrease. The diffusion of the conductor 542 into the oxide 530 can be expressed as the absorption of oxygen from the oxide 530 by the conductor 542. This can be done.

[0204] In addition, oxygen in the oxide 530 is converted into conductor 542 (conductor 542a and conductor 542b ) between the conductor 542a and the oxide 530b and between the conductor 542b A foreign layer may be formed between the conductor 542 and the oxide 530b. Since the conductor 54 also contains a large amount of oxygen, it is presumed that the different layer has insulating properties. The three-layer structure of the oxide 530b, the hetero layer 530b, and the oxide 530c is a three-layer structure consisting of a metal, an insulator, and a semiconductor. It can be considered as a MIS (Metal-Insulator-Semiconductor) structure. In some cases, it is called a diode junction structure, or a MIS structure is mainly used. be.

[0205] The different layer is not limited to being formed between the conductor 542 and the oxide 530b. For example, a different layer may be formed between the conductor 542 and the oxide 530c, or between the conductor 542 and the oxide 530c. 42 and oxide 530b, and between conductor 542 and oxide 530c. There are cases where this happens.

[0206] In addition, the metal oxide that functions as a channel formation region in the oxide 530 is a band gap. It is preferable to use a material with a gap of 2 eV or more, preferably 2.5 eV or more. As shown in Fig. 1, by using a metal oxide with a wide band gap, the off-state current of a transistor can be reduced. It can be reduced.

[0207] The oxide 530 has an oxide 530a under the oxide 530b, so that the oxide 530a The diffusion of impurities from structures formed below the oxide 530b can be suppressed. Furthermore, by having the oxide 530c on the oxide 530b, the oxide 530c can be formed. Therefore, the diffusion of impurities from the structure formed above into the oxide 530b can be suppressed. do.

[0208] The oxide 530 has a laminated structure of a plurality of oxide layers with different atomic ratios of each metal atom. Specifically, in the metal oxide used for the oxide 530a, it is preferable to use The atomic ratio of element M in the metal oxide used for oxide 530b is It is preferable that the atomic ratio of the metal oxide used for the oxide 530a is larger than that of the element M. In the oxide 530b, the atomic ratio of element M to In is In the oxide 530b, the atomic ratio of the element M to In is preferably larger than that of the element M. In the metal oxide used for the oxide 530a, the atomic ratio of In to the element M is In the metal oxide, the atomic ratio of In to the element M is preferably larger than that of In. The oxide 530c is a metal oxide that can be used for the oxide 530a or the oxide 530b. Compounds can be used.

[0209] The energy of the conduction band minimum of the oxide 530a and the oxide 530c is It is preferable that the energy of the conduction band minimum of 0b is higher than that of the oxide. The electron affinity of the oxide 530a and the oxide 530c is smaller than the electron affinity of the oxide 530b. It is preferable that

[0210] Here, at the junctions of oxide 530a, oxide 530b, and oxide 530c, The energy level of the conduction band minimum changes gradually. The energy level of the conduction band minimum at the junction of the oxide 530b and the oxide 530c is It can also be said that the oxide layer is continuously changed or continuously bonded. At the interface between oxide 530a and oxide 530b, and at the interface between oxide 530b and oxide 530c In this case, the defect level density of the mixed layer formed in the step (b) is preferably reduced.

[0211] Specifically, oxide 530a and oxide 530b, and oxide 530b and oxide 530c are By having a common element other than oxygen as the main component, a mixed layer with a low defect level density is formed. For example, when the oxide 530b is an In-Ga-Zn oxide, the oxide 53 0a and oxide 530c, such as In-Ga-Zn oxide, Ga-Zn oxide, and gallium oxide. It is recommended to use sodium etc.

[0212] At this time, the main path of the carriers is the oxide 530b. By configuring 30c as described above, the interface between oxide 530a and oxide 530b and the oxide This can reduce the defect state density at the interface between the oxide 530b and the nitride 530c. Therefore, the influence of interface scattering on carrier conduction is reduced, and the transistor 500 has high A large on-current can be obtained.

[0213] On the oxide 530b, a conductor 542 is formed, which functions as a source electrode and a drain electrode. (conductor 542a and conductor 542b) are provided. Aluminum, chromium, copper, silver, gold, platinum, tantalum, nickel, titanium, molybdenum, tantalum Gusten, hafnium, vanadium, niobium, manganese, magnesium, zirconium, Choose from beryllium, indium, ruthenium, iridium, strontium, and lanthanum. or an alloy containing the above-mentioned metal elements or a combination of the above-mentioned metal elements. It is preferable to use an alloy of tantalum nitride, titanium nitride, tungsten nitride, etc. titanium and aluminum nitrides, tantalum and aluminum nitrides, and titanium oxides Ruthenium, ruthenium nitride, oxides containing strontium and ruthenium, lanthanum and nickel It is preferable to use oxides containing titanium. Nitrides containing tantalum and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide , ruthenium nitride, oxides containing strontium and ruthenium, oxides containing lanthanum and nickel Oxides are conductive materials that are resistant to oxidation or that maintain conductivity even after absorbing oxygen. Therefore, it is preferable.

[0214] As shown in FIG. 10A, the oxide 530 has a thin film at the interface with the conductor 542 and in the vicinity thereof. In the case where the region 543 (region 543a and region 543b) is formed as a low resistance region, In this case, the region 543a functions as either a source region or a drain region. The region 543b functions as the other of the source region and the drain region. A channel forming region is formed in the region sandwiched between 3a and region 543b.

[0215] By providing the conductor 542 so as to be in contact with the oxide 530, the oxygen concentration in the region 543 In addition, the metal contained in the conductor 542 and the oxide 53 In such a case, a metal compound layer containing the component 0 may be formed. The carrier concentration increases, and region 543 becomes a low resistance region.

[0216] The insulator 544 is provided to cover the conductor 542 and prevents oxidation of the conductor 542. At this time, the insulator 544 covers the side surface of the oxide 530 and is in contact with the insulator 524. It may be provided.

[0217] Insulator 544 includes hafnium, aluminum, gallium, yttrium, and zirconium. Sm, tungsten, titanium, tantalum, nickel, germanium, or magnesium A metal oxide containing one or more metals selected from the group consisting of fluorine, fluorine, arsenic ...

[0218] In particular, the insulator 544 may be an oxide of aluminum or hafnium or both. Insulators containing aluminum oxide, hafnium oxide, hafnium aluminate, etc. In particular, hafnium aluminate is more effective than hafnium oxide. Therefore, it is preferable because it is difficult to crystallize during heat treatment in the subsequent process. It should be noted that the conductor 542 is made of a material that is resistant to oxidation or that does not become significantly conductive even when it absorbs oxygen. If the insulator 544 does not decrease, the insulator 544 is not an essential component. Therefore, it can be designed appropriately.

[0219] The insulator 550 functions as a gate insulating film. The insulator 550 is preferably disposed in contact with the upper and side surfaces of the substrate. For example, it is preferable to form the insulating layer using an insulator that releases oxygen. The amount of oxygen released in terms of atoms is 1.0 x 10 18 atoms / cm 3 Above, preferably 1.0×10 19 atoms / cm 3 More preferably, 2.0 × 10 19 atom s / cm 3 or more, or 3.0 x 10 20 atoms / cm 3 The oxide film is The surface temperature of the film during the TDS analysis was in the range of 100°C to 700°C. The surrounding area is preferred.

[0220] Specifically, silicon oxide having excess oxygen, silicon oxynitride, silicon nitride oxide, Silicon nitride, fluorine-doped silicon oxide, carbon-doped silicon oxide, carbon and Silicon oxide doped with nitrogen and silicon oxide having vacancies can be used. Silicon oxide and silicon oxynitride are preferred because they are stable to heat.

[0221] An insulator that releases oxygen when heated is used as the insulator 550, and is placed on the top surface of the oxide 530c. By providing the oxide 530b in contact with the insulator 550, the oxide 530c passes through the oxide 530b. In addition, oxygen can be effectively supplied to the channel formation region of the insulator 524. In addition, it is preferable that the concentration of impurities such as water or hydrogen in the insulator 550 is reduced. The thickness of the insulator 550 is preferably 1 nm or more and 20 nm or less.

[0222] In addition, in order to efficiently supply excess oxygen contained in the insulator 550 to the oxide 530, A metal oxide may be provided between the insulating material 550 and the conductor 560. It is preferable to suppress the diffusion of oxygen from the body 550 to the conductor 560. By providing a metal oxide, the diffusion of excess oxygen from the insulator 550 to the conductor 560 is suppressed. In other words, it is possible to suppress the decrease in the amount of excess oxygen supplied to the oxide 530. In addition, oxidation of the conductor 560 due to excess oxygen can be suppressed. Any material that can be used for the insulator 544 may be used.

[0223] The conductor 560 functioning as the first gate electrode has a two-layer structure in FIGS. 10A and 10B. However, it may have a single layer structure or a laminated structure of three or more layers.

[0224] The conductor 560a is a hydrogen atom, a hydrogen molecule, a water molecule, a nitrogen atom, a nitrogen molecule, or a nitrogen oxide molecule. (N2O, NO, NO2, etc.), conductive material with the function of suppressing the diffusion of impurities such as copper atoms It is preferable to use a material containing a small amount of oxygen (for example, oxygen atoms, oxygen molecules, etc.). It is preferable to use a conductive material that has the function of suppressing the diffusion of at least one of the conductors. Since 560a has the function of suppressing the diffusion of oxygen, the oxygen contained in the insulator 550 This can prevent the conductor 560b from being oxidized and the conductivity from decreasing. Examples of conductive materials that have the function of suppressing diffusion include tantalum, tantalum nitride, and ruthenium. It is preferable to use ruthenium or ruthenium oxide.

[0225] The conductor 560b is a conductive material mainly composed of tungsten, copper, or aluminum. In addition, since the conductor 560b also functions as a wiring, It is preferable to use a conductor with high conductivity, such as tungsten, copper, or aluminum. The conductor 560b can be made of a conductive material containing aluminum as a main component. For example, a laminated structure of titanium or titanium nitride and the above conductive material may be used. Good too.

[0226] The insulator 580 is provided on the conductor 542 via the insulator 544. Preferably, the insulator 580 has an excess oxygen region. For example, silicon oxide is used as the insulator 580. , silicon oxynitride, silicon nitride oxide, silicon nitride, fluorine-doped silicon oxide , carbon-doped silicon oxide, carbon- and nitrogen-doped silicon oxide, vacancy-containing silicon oxide It is preferable that the insulating layer contains silicon oxide or resin. In particular, silicon oxide and oxide Silicon nitride is preferred because it is thermally stable. In particular, silicon oxide and vacant oxide are preferred. Silicon dioxide is preferred because it allows for easy formation of an excess oxygen region in a subsequent step.

[0227] The insulator 580 preferably has an excess oxygen region. Oxygen is released upon heating. By providing the insulator 580 in contact with the oxide 530c, the oxygen in the insulator 580 is oxidized. The oxide 530 can be efficiently supplied through the insulator 530c. It is preferable that the concentration of impurities such as water or hydrogen in 80 is reduced.

[0228] The opening in the insulator 580 is formed to overlap the region between the conductor 542a and the conductor 542b. As a result, the conductor 560 is connected to the opening of the insulator 580 and the conductor 542a. It is formed so as to be embedded in the region sandwiched between the bodies 542b.

[0229] In miniaturizing semiconductor devices, it is required to shorten the gate length. It is necessary to prevent the conductivity of the conductor 60 from decreasing. In this embodiment, the conductor 560 may have a shape with a high aspect ratio. The conductor 560 is provided so as to be embedded in the opening of the insulator 580. Even a shape with a high ratio can be formed without causing the conductor 560 to collapse during the process. Cut.

[0230] The insulator 574 is disposed on the top surface of the insulator 580, the top surface of the conductor 560, and the top surface of the insulator 550. The insulator 574 is preferably provided in contact with the surface. Thus, an excess oxygen region can be provided in the insulator 550 and the insulator 580. From this excess oxygen region, oxygen can be supplied into the oxide 530 .

[0231] For example, the insulator 574 may be hafnium, aluminum, gallium, yttrium, Zirconium, tungsten, titanium, tantalum, nickel, germanium, or magnesium It is possible to use a metal oxide containing one or more metals selected from the group consisting of cadmium, cadmium, and sulphur. Cut.

[0232] In particular, aluminum oxide has a high barrier property and is a thin film of 0.5 nm to 3.0 nm. Therefore, the diffusion of hydrogen and nitrogen can be suppressed even if sputtering is performed. The aluminum oxide film formed by this method is a source of oxygen and also a barrier for impurities such as hydrogen. It can also function as a film.

[0233] In addition, it is preferable to provide an insulator 581 that functions as an interlayer film over the insulator 574. The insulator 581, like the insulator 524, has a low impurity concentration such as water or hydrogen in the film. is preferably reduced.

[0234] Also, the insulating material 581, the insulating material 574, the insulating material 580, and the insulating material 544 are formed. The conductor 540a and the conductor 540b are placed in the opening. The conductors 540a and 540b are provided opposite each other with the conductor 560 in between. b has the same configuration as conductor 546 and conductor 548 described later.

[0235] An insulator 582 is provided on the insulator 581. The insulator 582 is resistant to oxygen and hydrogen. Therefore, the insulator 582 is preferably made of an insulating material. The insulator 582 may be made of the same material as the insulator 514. For example, aluminum oxide may be used. It is preferable to use metal oxides such as tungsten oxide, hafnium oxide, and tantalum oxide.

[0236] In particular, aluminum oxide is highly resistant to oxygen and water, which can cause fluctuations in the electrical characteristics of transistors. It has a high blocking effect that prevents impurities such as oxygen and moisture from penetrating the membrane. Aluminum oxide is a material that can withstand hydrogen, moisture, and other chemicals during and after the transistor manufacturing process. This can prevent impurities from entering the transistor 500. This can suppress the release of oxygen from the oxide that makes up the transistor. It is suitable for use as a protective film for the substrate 500.

[0237] An insulator 586 is provided on the insulator 582. The insulator 586 is The same material as that of 320 can be used. In addition, a material with a relatively low dielectric constant can be used as the interlayer film. For example, the insulator 586 may be For example, a silicon oxide film or a silicon oxynitride film can be used.

[0238] Also, the insulator 520, the insulator 522, the insulator 524, the insulator 544, the insulator 580, the insulator The insulator 574, the insulator 581, the insulator 582, and the insulator 586 are provided with the conductor 546 and and a conductor 548 and the like are embedded therein.

[0239] The conductor 546 and the conductor 548 are connected to the capacitor 600, the transistor 500, or The conductor 546 functions as a plug or wiring that connects to the transistor 300. The conductor 548 is made of the same material as the conductor 328 and the conductor 330. It is possible.

[0240] Next, a capacitor 600 is provided above the transistor 500. 600 includes a conductor 610, a conductor 620, and an insulator 630.

[0241] Furthermore, a conductor 612 may be provided over the conductor 546 and the conductor 548. 612 has a function as a plug or wiring that connects to the transistor 500. The conductor 610 functions as an electrode of the capacitor 600. The conductive material 610 and the conductive material 610 can be formed simultaneously.

[0242] In FIG. 9 and other figures, an example is shown in which an insulator 630 is used as the dielectric of the capacitor element. Other insulators may be used as the conductors. It may be used.

[0243] For example, an insulator 315 may be used to function as a gate insulator for transistor 300. When the insulator 315 is used as a dielectric of the capacitor element, the conductor 316 is used as the One of the electrodes, such as the low resistance region 314a, may be used as the other electrode.

[0244] Conductor 612 and conductor 610 may be made of molybdenum, titanium, tantalum, tungsten, or the like. Metal film containing elements selected from the group consisting of silicon, aluminum, copper, chromium, neodymium, and scandium or a metal nitride film containing the above-mentioned elements (tantalum nitride film, titanium nitride film, nitride Molybdenum film, tungsten nitride film, etc. can be used. oxides containing tungsten oxide, indium zinc oxides containing tungsten oxide Lead oxide, indium oxide with titanium oxide, indium tin oxide with titanium oxide, Conductive materials such as indium zinc oxide and indium tin oxide doped with silicon oxide are used. It can also be used.

[0245] In FIG. 9, the conductor 612 and the conductor 610 are shown as a single layer structure. For example, a conductive material having a barrier property and a conductive material having a barrier property may be used. Conductors with barrier properties and highly conductive conductors A highly adhesive conductor may be formed.

[0246] The conductor 620 is provided so as to overlap with the conductor 610 with the insulator 630 interposed therebetween. The conductor 620 is made of a conductive material such as a metal material, an alloy material, or a metal oxide material. High-melting-point materials such as tungsten and molybdenum, which are both heat-resistant and conductive, are used. It is preferable to use tungsten, and it is particularly preferable to use tungsten. When forming the structure at the same time as other structures, low-resistance metal materials such as Cu (copper) and Al (aluminum) are used. You can use a .um.

[0247] An insulator 650 is provided on the conductor 620 and the insulator 630. The insulator 50 can be made of the same material as the insulator 320. , and may function as a planarizing film that covers the underlying unevenness.

[0248] By using this structure, a semiconductor device using a transistor having an oxide semiconductor This makes it possible to suppress fluctuations in electrical characteristics and improve reliability. A transistor including an oxide semiconductor and having a large on-state current can be provided. It is possible to provide a transistor including an oxide semiconductor with low current. A semiconductor device having an oxide semiconductor can be provided. In a semiconductor device using a transistor, miniaturization or high integration can be achieved.

[0249] <Example of transistor structure> Note that the transistor 500 of the semiconductor device described in this embodiment is not limited to the above structure. The following describes examples of structures that can be used for the transistor 500. .

[0250] <Transistor structure example 1> An example of the structure of the transistor 510A will be described with reference to FIGS. 11A, 11B, and 11C. 11A is a top view of transistor 510A. 11C is a cross-sectional view of the area indicated by the dashed line W1-W2 in FIG. 11A is a cross-sectional view of the part. Note that in the top view of FIG. 11A, some elements are omitted for clarity. The diagram is as follows:

[0251] 11A, 11B, and 11C, a transistor 510A and a semiconductor device 510B functioning as an interlayer film are shown. Insulators 511, 512, 514, 516, 580, and 582, and insulator 584. Also shown are transistors 510A and 510B. The conductors 546 (conductors 546a and 546b) functioning as contact plugs 6b) and a conductor 503 that functions as a wiring.

[0252] The transistor 510A has a conductor 560 (conductor 56 0a and conductor 560b), and conductor 505 (which functions as a second gate electrode). and a conductive material 505a and a conductive material 505b), and an insulator 55 which functions as a first gate insulating film. 0, and insulators 521, 522, and 523 functioning as a second gate insulating film. 24 and an oxide 530 (oxide 530a, oxide 53 0b, and oxide 530c) and a conductor 530 serving as either a source or a drain. 42a, a conductor 542b serving as the other of the source and drain, and an insulator 574 and

[0253] In addition, in the transistor 510A shown in FIG. 11, the oxide 530c, the insulator 550, and The conductor 560 is disposed in an opening provided in the insulator 580 via the insulator 574. The oxide 530c, the insulator 550, and the conductor 560 are connected to the conductor 542a, and conductor 542b.

[0254] The insulators 511 and 512 function as interlayer films.

[0255] The interlayer film may be silicon oxide, silicon oxynitride, silicon nitride oxide, or aluminum oxide. ammonium, hafnium oxide, tantalum oxide, zirconium oxide, PZT, SrTiO3 or Insulators such as (Ba,Sr)TiO3 (BST) can be used in single or multilayer configurations. Alternatively, for example, aluminum oxide, bismuth oxide, germanium oxide, etc. may be added to these insulators. Niobium oxide, silicon oxide, titanium oxide, tungsten oxide, yttrium oxide, Alternatively, zirconium oxide may be added to these insulators, or these insulators may be nitrided. Silicon oxide, silicon oxynitride, or silicon nitride may be stacked on the insulator.

[0256] For example, the insulator 511 prevents impurities such as water or hydrogen from entering the transistor 51 from the substrate side. It is preferable that the insulating film functions as a barrier film that prevents the inclusion of OA. The body 511 has a function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, and copper atoms. It is preferable to use an insulating material that has high oxygen content (which is difficult for the impurities to penetrate). (e.g., at least one of oxygen atoms, oxygen molecules, etc.) It is preferable to use an insulating material that is difficult for oxygen to permeate. Aluminum oxide or silicon nitride may be used as the material 11. Impurities such as water diffuse from the substrate side to the transistor 510A side rather than the insulator 511. can be suppressed.

[0257] For example, the insulator 512 preferably has a lower dielectric constant than the insulator 511. By using a low-cost material for the interlayer film, the parasitic capacitance occurring between wirings can be reduced.

[0258] The conductor 503 is formed so as to be embedded in the insulator 512. The height of the upper surface of the conductor 503 can be made to be approximately the same as the height of the upper surface of the insulator 512. Although a single layer structure is shown, the present invention is not limited to this. For example, The conductor 503 may have a multilayer structure of two or more layers. It is preferable to use a highly conductive material containing silicon, copper, or aluminum as the main component. It's nice.

[0259] In transistor 510A, conductor 560 is connected to the first gate (also known as the top gate). The conductor 505 may function as a second gate (bottom gate). In this case, the voltage applied to the conductor 505 may function as an electrode. The potential of the transistor 560 is changed independently of the potential applied to the conductor 560. In particular, applying a negative potential to the conductor 505 allows the threshold voltage of the conductor 510A to be controlled. By applying this voltage, the threshold voltage of transistor 510A is increased above 0V, and the off-state voltage Therefore, it is preferable to apply a negative potential to the conductor 505. When the potential applied to the conductor 560 is 0 V, the drain current is smaller than when the potential is not applied. It can be reduced.

[0260] In addition, for example, by providing the conductor 505 and the conductor 560 so that they overlap with each other, the conductor 56 0, and when a potential is applied to the conductor 505, the electric field generated by the conductor 560 and the conductor The electric field generated from 505 is connected to the oxide 530, and the channel forming region is covered. It is possible to do so.

[0261] That is, the electric field of the conductor 560 functioning as the first gate electrode and the electric field of the second gate electrode The electric field of the conductor 505, which functions as an electrode, electrically connects the channel forming region. That is, similar to the transistor 500 described above, the S-channel It is a nel structure.

[0262] The insulators 514 and 516 are layers similar to the insulators 511 and 512. For example, the insulator 514 functions as a barrier film to prevent impurities such as water or hydrogen from entering the substrate. It is preferable that the film functions as a barrier film that prevents the metal oxide from entering the transistor 510A. This structure allows impurities such as hydrogen and water to pass through the insulator 514 from the substrate side to the transistor. 510A. It is preferable that the dielectric constant of the interlayer film is lower than that of the substrate 514. By using a material with a low dielectric constant as the interlayer film, The parasitic capacitance occurring between the wirings can be reduced.

[0263] Conductor 505, which functions as a second gate, is connected to openings in insulators 514 and 516. A conductor 505a is formed in contact with the inner wall of the Here, the height of the upper surfaces of the conductors 505a and 505b and the upper surface of the insulator 516 are In the transistor 510A, the heights of the conductors 505a and 505b can be made approximately the same. Although the structure in which the bodies 505b are stacked is shown, the present invention is not limited to this. For example, the conductor 505 may be provided as a single layer or a laminated structure of three or more layers. good.

[0264] Here, the conductor 505a is a diffusion layer for impurities such as hydrogen atoms, hydrogen molecules, water molecules, and copper atoms. It is preferable to use a conductive material that has the function of suppressing the impurities (i.e., the impurities are less likely to permeate). Alternatively, the diffusion of oxygen (for example, at least one of oxygen atoms, oxygen molecules, etc.) can be suppressed. It is preferable to use a conductive material that has the function of preventing oxygen from permeating. In this specification, the function of suppressing the diffusion of impurities or oxygen means the function of suppressing the diffusion of the above impurities or oxygen. has the function of suppressing the diffusion of any one or all of the above oxygen species.

[0265] For example, the conductor 505a has a function of suppressing the diffusion of oxygen, so that the conductor 505 This can prevent b from being oxidized and the electrical conductivity from decreasing.

[0266] When the conductor 505 also functions as a wiring, the conductor 505b is made of tungsten, copper, or the like. It is preferable to use a conductive material having high conductivity, such as aluminum or aluminum-based. In this case, the conductor 503 is not necessarily provided. However, it may have a laminated structure, for example, a layer of titanium or titanium nitride and the above conductive material. It may also be laminated with other materials.

[0267] The insulators 521, 522, and 524 function as a second gate insulating film. Possess the ability.

[0268] Furthermore, the insulator 522 preferably has a barrier property. By having this, impurities such as hydrogen from the periphery of the transistor 510A to the transistor 510A can be prevented. It functions as a layer that suppresses the inclusion of impurities.

[0269] The insulator 522 may be, for example, aluminum oxide, hafnium oxide, or hafnium aluminate. tantalum oxide, zirconium oxide, PZT, SrTiO3 or (Ba,Sr)Ti Insulators including so-called high-k materials such as O3 (BST) are used in single or multilayer configurations. As transistors become smaller and more highly integrated, the thickness of the gate insulating film becomes thinner. This may cause problems such as leakage current. By using high-k material for the body, the gate electrode during transistor operation can be made thinner while maintaining the physical film thickness. This makes it possible to reduce the gate potential.

[0270] The insulator 521 is preferably thermally stable. For example, silicon oxide and Silicon oxide nitride and silicon oxynitride are suitable because they are thermally stable. By combining this insulator with silicon oxide or silicon oxynitride, Furthermore, it is possible to obtain the insulator 521 having a laminated structure with a high relative dielectric constant.

[0271] Although FIG. 11 shows a three-layer laminated structure as the second gate insulating film, it may be a single layer or In this case, the laminated structure is limited to the laminated structure made of the same material. Alternatively, it may have a laminated structure made of different materials.

[0272] The oxide 530 having a region that functions as a channel formation region is formed by an oxide 530a and an oxide The oxide 530b is on the oxide 530a, and the oxide 530c is on the oxide 530b. By having the oxide 530a under the oxide 530b, the oxide 530b is formed below the oxide 530a. The diffusion of impurities from the oxide 530b to the oxide 530b can be suppressed. By having oxide 530c on object 530b, the oxide 530c is formed above the oxide 530c. The diffusion of impurities from the structure to the oxide 530b can be suppressed. As the material, an oxide semiconductor, which is one of the above-mentioned metal oxides, can be used.

[0273] The oxide 530c is formed in the opening of the insulator 580 through the insulator 574. When the insulator 574 has a barrier property, the insulating material 574 is preferably provided with a barrier layer. This can prevent impurities from diffusing into the oxide 530.

[0274] One of the conductors 542 functions as a source electrode and the other functions as a drain electrode. .

[0275] The conductor 542a and the conductor 542b are made of aluminum, titanium, chromium, nickel, Copper, yttrium, zirconium, molybdenum, silver, tantalum, or tungsten, etc. In particular, tantalum nitride, etc. The metal nitride film has barrier properties against hydrogen and oxygen, and is highly resistant to oxidation. ,preferable.

[0276] Although a single layer structure is shown in FIG. 11, a laminated structure of two or more layers may be used. It is preferable to stack a tantalum chloride film and a tungsten film. It is also preferable to stack a titanium film and an aluminum film. Alternatively, a two-layer structure in which an aluminum film is laminated on a tungsten film, or a copper-magnesium film may be used. Two-layer structure with copper film laminated on top of a titanium film. Alternatively, a two-layer structure in which a copper film is laminated on a tungsten film may be used.

[0277] Also, a titanium film or titanium nitride film and an aluminum film overlaid on the titanium film or titanium nitride film are used. An aluminum film or a copper film is laminated, and a titanium film or a titanium nitride film is further formed thereon. A three-layer structure consisting of a molybdenum film or molybdenum nitride film and a molybdenum film or molybdenum nitride film. An aluminum or copper film is layered on top of the molybdenum film, and then a molybdenum or There are three-layer structures in which indium oxide, tin oxide or molybdenum nitride are formed. Alternatively, a transparent conductive material containing zinc oxide may be used.

[0278] A barrier layer may be provided on the conductor 542. The barrier layer is resistant to oxygen or hydrogen. It is preferable to use a substance having a barrier property against the insulator 574. During film formation, the conductor 542 can be prevented from being oxidized.

[0279] The barrier layer may be made of, for example, a metal oxide, particularly aluminum oxide, Using insulating films such as hafnium oxide and gallium oxide that have barrier properties against oxygen and hydrogen It is also preferable to use silicon nitride formed by the CVD method.

[0280] The barrier layer can broaden the range of material options for the conductor 542. For example, The conductor 542 is made of tungsten or aluminum, which has low oxidation resistance but high conductivity. In addition, for example, a conductive material that is easy to form a film or process can be used. You can be there.

[0281] The insulator 550 functions as a first gate insulating film. The oxide 530c and the insulator 574 are provided in the opening provided in the is preferred.

[0282] As transistors become smaller and more highly integrated, the gate insulating film becomes thinner, which reduces the lead In this case, the insulator 550 may be a second gate insulating film. Similarly, a stacked structure may be used. By using a laminated structure of a material and a thermally stable material, the thickness of the material can be maintained while maintaining the thickness of the material. This allows the gate potential to be reduced during transistor operation. A thin laminated structure can be obtained.

[0283] The conductor 560 functioning as the first gate electrode is made up of the conductor 560a and the conductor 56 Conductor 560a has a conductor 560b on top of conductor 505a. Conductor 560a is a hydrogen atom, similar to conductor 505a. Conductive materials that have the function of suppressing the diffusion of impurities such as electrons, hydrogen molecules, water molecules, and copper atoms. It is preferable to use at least one of oxygen (for example, oxygen atom, oxygen molecule, etc.) It is preferable to use a conductive material that has the function of suppressing the diffusion of (1).

[0284] The conductor 560a has a function of suppressing the diffusion of oxygen, and therefore the material of the conductor 560b In other words, by having the conductor 560a, the conductor 560 The oxidation of b is suppressed, and the decrease in electrical conductivity can be prevented.

[0285] Examples of conductive materials that have the function of suppressing oxygen diffusion include tantalum and tantalum nitride. It is preferable to use ruthenium, ruthenium oxide, or the like. As Oa, an oxide semiconductor that can be used as the oxide 530 can be used. In this case, the conductor 560b is formed by sputtering, so that the electric potential of the conductor 560a is reduced. This is called OC (Oxide Conductor). The electrode can be called a conductor electrode.

[0286] The conductor 560b is made of a conductive material mainly composed of tungsten, copper, or aluminum. In addition, since the conductor 560 functions as a wiring, it is preferable to use a material having high conductivity. It is preferable to use a conductor that is strong enough to withstand the heat. For example, tungsten, copper, or aluminum may be used as the main material. The conductor 560b may have a layered structure. For example, a laminate of titanium or titanium nitride and the above conductive material may be used.

[0287] An insulator 574 is disposed between the insulator 580 and the transistor 510A. 4 is an insulating material that has the function of suppressing the diffusion of impurities such as water or hydrogen, and oxygen. For example, aluminum oxide or hafnium oxide is preferably used. In addition, other examples include magnesium oxide, gallium oxide, germanium oxide, Yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide or tantalum oxide Metal oxides such as silicon nitride oxide or silicon nitride can be used.

[0288] By including the insulator 574, impurities such as water and hydrogen contained in the insulator 580 can be converted into an acid. The oxide 530c is prevented from diffusing into the oxide 530b through the insulator 550. In addition, the excess oxygen contained in the insulator 580 can prevent the conductor 560 from being oxidized. It is possible.

[0289] Insulators 580, 582, and 584 function as interlayer films.

[0290] The insulator 582, like the insulator 514, prevents impurities such as water or hydrogen from traversing the It is preferable that the insulating film functions as a barrier insulating film that prevents the metal from being mixed into the transistor 510A.

[0291] In addition, the insulators 580 and 584, like the insulator 516, are thicker than the insulator 582. By using a material with a low dielectric constant as the interlayer film, the This can reduce the parasitic capacitance.

[0292] Also, transistor 510A is connected to insulators 580, 582, and 584. Electrical connections to other structures may be made through plugs or wiring such as embedded conductors 546. good.

[0293] The material of the conductor 546 may be a metal material, an alloy material, or a gold material, similar to the conductor 505. Conductive materials such as metal nitride materials or metal oxide materials can be used as a single layer or a laminate. For example, high-melting-point materials such as tungsten and molybdenum, which have both heat resistance and electrical conductivity, can be used. It is preferable to use a material such as aluminum or copper. It is preferable to use a low-resistance conductive material to reduce wiring resistance. .

[0294] For example, the conductor 546 may be a conductor having barrier properties against hydrogen and oxygen. By using a layered structure of tantalum nitride, which has low electrical conductivity, and tungsten, which has high electrical conductivity, This makes it possible to suppress the diffusion of impurities from the outside while maintaining the overall conductivity.

[0295] By using the above structure, a transistor including an oxide semiconductor with a large on-state current can be used. Alternatively, a semiconductor device having an oxide semiconductor with a small off-state current can be provided. A semiconductor device using a transistor can be provided. To provide a semiconductor device having stable electrical characteristics and improved reliability. can be done.

[0296] <Transistor structure example 2> An example of the structure of the transistor 510B will be described with reference to FIGS. 12A, 12B, and 12C. 12A is a top view of transistor 510B. 12A is a cross-sectional view of the area indicated by the dashed line W1-W2 in FIG. 12A is a cross-sectional view of the part. Note that in the top view of FIG. 12A, some elements are omitted for clarity. The diagram is as follows:

[0297] Transistor 510B is a modification of transistor 510A. To avoid confusion, differences from transistor 510A will be mainly described.

[0298] Transistor 510B has conductors 542 (conductors 542a and 542b) and , the oxide 530c, the insulator 550, and the conductor 560 overlap each other. With this structure, a transistor with a high on-state current can be provided. Therefore, a highly efficient transistor can be provided.

[0299] The conductor 560 functioning as the first gate electrode is made up of the conductor 560a and the conductor 56 Conductor 560a has a conductor 560b on top of conductor 505a. Conductor 560a is a hydrogen atom, similar to conductor 505a. Conductive materials that have the function of suppressing the diffusion of impurities such as electrons, hydrogen molecules, water molecules, and copper atoms. It is preferable to use at least one of oxygen (for example, oxygen atom, oxygen molecule, etc.) It is preferable to use a conductive material that has the function of suppressing the diffusion of (1).

[0300] The conductor 560a has a function of suppressing the diffusion of oxygen, and therefore the material of the conductor 560b In other words, by having the conductor 560a, the conductor 560 The oxidation of b is suppressed, and the decrease in electrical conductivity can be prevented.

[0301] In addition, the top and side surfaces of the conductor 560, the side surfaces of the insulator 550, and the oxide 530c It is preferable to provide an insulator 574 so as to cover the side surface. When an insulating material is used that has the function of suppressing the diffusion of impurities such as hydrogen and oxygen, For example, it is preferable to use aluminum oxide or hafnium oxide. Other examples include magnesium oxide, gallium oxide, germanium oxide, and yttrium oxide. metals such as sodium, zirconium oxide, lanthanum oxide, neodymium oxide or tantalum oxide Oxide, silicon nitride oxide, silicon nitride, or the like can be used.

[0302] By providing the insulator 574, oxidation of the conductor 560 can be suppressed. By providing the insulator 574, impurities such as water and hydrogen contained in the insulator 580 are absorbed into the transistor. This can prevent diffusion to resistor 510B.

[0303] In addition, an insulator 576 (insulator) having a barrier property is provided between the conductor 546 and the insulator 580. By providing the insulator 576, The oxygen in the insulator 580 reacts with the conductor 546, and the conductor 546 is prevented from being oxidized. This can be done.

[0304] In addition, by providing an insulator 576 having a barrier property, the conductive material used for the plug and wiring can be For example, the conductor 546 can be made of a material with oxygen-absorbing properties. While having high electrical conductivity, the use of metal materials provides a semiconductor device with low power consumption. Specifically, tungsten and aluminum have low oxidation resistance, but In addition, for example, a material that is easy to form a film or process can be used. A conductor may be used.

[0305] <Transistor structure example 3> An example of the structure of the transistor 510C will be described with reference to FIGS. 13A, 13B, and 13C. 13A is a top view of transistor 510C. 13C is a cross-sectional view of the area indicated by the dashed line W1-W2 in FIG. It should be noted that in the top view of FIG. 13A, some elements have been omitted for clarity. The diagram is as follows:

[0306] Transistor 510C is a modification of transistor 510A. To avoid confusion, differences from transistor 510A will be mainly described.

[0307] The transistor 510C shown in FIG. 13 has a conductor between the conductor 542a and the oxide 530b. 547a is disposed between the conductor 542b and the oxide 530b, and the conductor 547b is disposed between the conductor 542b and the oxide 530b. Here, the conductor 542a (conductor 542b) is connected to the conductor 547a (conductor 547b). b) and the side of the conductor 560, and contacts the top surface of the oxide 530b. Here, the conductor 547 uses a conductor that can be used for the conductor 542. Furthermore, the thickness of the conductor 547 is preferably at least thicker than that of the conductor 542. Desirable.

[0308] The transistor 510C shown in FIG. 13 has the above-described configuration. The conductor 542 can be closer to the conductor 560 than the resistor 510A. The end of the conductor 542a and the end of the conductor 542b can be overlapped with the conductor 560. This reduces the effective channel length of the transistor 510C, reducing the on-current and The frequency characteristics can be improved.

[0309] In addition, the conductor 547a (conductor 547b) overlaps with the conductor 542a (conductor 542b). By adopting such a configuration, the conductor 546a (the conductor In the etching to form the opening in which the conductor 547a (conductor 546b) is embedded, 47b) acts as a stopper to prevent over-etching of oxide 530b. It is possible.

[0310] 13. The transistor 510C shown in FIG. 13 has an insulator 545 in contact with the insulator 544. The insulator 544 may be formed by arranging impurities such as water or hydrogen, or by absorbing peroxide. A barrier insulating layer prevents excess oxygen from entering the transistor 510C from the insulator 580 side. It is preferable that the insulator 545 functions as an insulating film. As the insulator 544, for example, aluminum nitride can be used. aluminum, titanium aluminum nitride, titanium nitride, silicon nitride or silicon oxide nitride Nitride insulators such as may be used.

[0311] 11. The transistor 510C shown in FIG. 13 differs from the transistor 510A shown in FIG. In this case, the conductor 505 may have a single layer structure. An insulating film that will become the insulator 516 is formed on the conductor 505, and the upper part of the insulating film is The conductor 505 may be removed by a CMP method or the like until the flatness of the upper surface of the conductor 505 is reached. For example, it is preferable to make the average surface roughness (Ra) of the upper surface of the conductor 505 to 1 nm or less. The thickness may be set to 0.5 nm or less, preferably 0.3 nm or less. This improves the flatness of the insulating layer formed on the conductor 505, and the oxide 530b and This can improve the crystallinity of the oxide 530c.

[0312] <Transistor structure example 4> An example of the structure of the transistor 510D will be described with reference to FIGS. 14A, 14B, and 14C. 14A is a top view of transistor 510D. 14A. 14A is a cross-sectional view of the part. Note that in the top view of FIG. 14A, some elements are omitted for clarity. The diagram is as follows:

[0313] Transistor 510D is a variation of the transistor described above. To prevent this, differences from the above transistor will be mainly described.

[0314] 14A to 14C, the conductor 503 is not provided, and the function as the second gate is not provided. The conductor 505 also functions as a wiring. 0, and a metal oxide 552 on the insulator 550. The conductor 560 has an insulator 570 on the conductor 560. It has an edge 571.

[0315] The metal oxide 552 preferably has a function of suppressing oxygen diffusion. By providing a metal oxide 552 between the conductive material 560 and the conductive material 560, which suppresses the diffusion of oxygen, The diffusion of oxygen into the dielectric 560 is suppressed. In other words, the amount of oxygen supplied to the oxide 530 is reduced. In addition, oxidation of the conductor 560 by oxygen can be suppressed. .

[0316] Note that the metal oxide 552 may function as a part of the first gate. The oxide semiconductor that can be used as the oxide 530 is used as the metal oxide 552. In this case, the conductor 560 can be formed by sputtering to form a metal oxide film. The electrical resistance of the oxide 552 can be reduced to make it a conductive layer. This is called an OC electrode. It is possible.

[0317] The metal oxide 552 may also function as a part of the gate insulating film. Therefore, when silicon oxide or silicon oxynitride is used for the insulator 550, the metal oxide The material 552 is preferably a metal oxide, which is a high-k material having a high dielectric constant. This laminated structure is stable against heat and has a high dielectric constant. Therefore, the gate voltage applied during transistor operation can be adjusted while maintaining the physical film thickness. In addition, the equivalent oxide thickness ( It is possible to reduce the thickness of the EOT.

[0318] In the transistor 510D, the metal oxide 552 is shown as a single layer, but it may be a stack of two or more layers. For example, a metal oxide that functions as a part of the gate electrode and a gate insulating film may be used. A metal oxide that functions as part of the film may be laminated.

[0319] When the metal oxide 552 functions as a gate electrode, It is possible to improve the on-current of transistor 510D without weakening the influence of these electric fields. Alternatively, when it functions as a gate insulating film, the insulating film 550 and the metal oxide 55 2, the physical thickness of the conductor 560 and the oxide 530 are kept at a distance from each other. The leakage current between the conductor 560 and the oxide 530 can be suppressed. By providing a stacked structure of the conductor 550 and the metal oxide 552, the conductor 560 and the oxide The physical distance between the conductor 560 and the oxide 530, and the electric field strength acting on the oxide 530 from the conductor 560 are , and can be easily adjusted appropriately.

[0320] Specifically, the metal oxide 552 may be an oxide semiconductor that can be used for the oxide 530. By lowering the resistance of the body, it can be used as metal oxide 552. Um, aluminum, gallium, yttrium, zirconium, tungsten, titanium, One selected from tantalum, nickel, germanium, or magnesium, or A metal oxide containing two or more kinds of metals can be used.

[0321] In particular, the insulating layer contains oxides of either or both of aluminum and hafnium. It is preferable to use aluminum oxide, hafnium oxide, hafnium aluminate, etc. In particular, hafnium aluminate has higher heat resistance than hafnium oxide film. Therefore, it is preferable that the metal oxide 5 is hard to crystallize in the heat treatment in the subsequent process. 52 is not an essential component. It can be designed appropriately depending on the desired transistor characteristics. .

[0322] The insulator 570 has a function of suppressing the permeation of impurities such as water or hydrogen, and oxygen. For example, aluminum oxide or hafnium oxide can be used. This prevents the conductor 560 from being damaged by oxygen from above the insulator 570. In addition, the insulator 570 can prevent water or hydrogen from flowing from above the insulator 570. Impurities such as ions may be mixed into the oxide 530 via the conductor 560 and the insulator 550. This can suppress the above.

[0323] The insulator 571 functions as a hard mask. When processing 60, the side of the conductor 560 is approximately perpendicular, specifically, the side of the conductor 560 and the substrate The angle formed by the plate surface is 75 degrees or more and 100 degrees or less, preferably 80 degrees or more and 95 degrees or less. This can be done.

[0324] The insulator 571 has a function of suppressing the permeation of impurities such as water or hydrogen, and oxygen. By using an insulating material having the above structure, the insulating material may also function as a barrier layer. In this case, the insulator 570 may not be provided.

[0325] The insulator 571 is used as a hard mask to form the insulator 570, the conductor 560, and the metal oxide 552, insulator 550, and oxide 530c are selectively removed to remove these The side surfaces of the oxide 530b can be made substantially flush with each other, and part of the surface of the oxide 530b can be exposed.

[0326] Transistor 510D also has regions 531a and 531b on a portion of the exposed oxide 530b surface. and region 531b. One of region 531a or region 531b is used as a source region. one functions as a drain region, and the other functions as a drain region.

[0327] The regions 531a and 531b can be formed by, for example, ion implantation or ion doping. The exposed oxide is then removed using a method such as plasma immersion ion implantation or plasma treatment. This can be achieved by introducing impurity elements such as phosphorus or boron into the surface of the oxide 530b. In this embodiment, the term "impurity element" refers to an element other than the main component element. .

[0328] In addition, after exposing a part of the surface of the oxide 530b, a metal film is formed and then heat-treated. By this, the elements contained in the metal film are diffused into the oxide 530b, and the regions 531a and A region 531b can also be formed.

[0329] The region of the oxide 530b into which the impurity element is introduced has a reduced electrical resistivity. The regions 531a and 531b may be referred to as "impurity regions" or "low resistance regions." do.

[0330] By using the insulator 571 and / or the conductor 560 as a mask, the region 531a The region 531b can be formed in a self-aligned manner. Therefore, the region 531a and / or the region 531b do not overlap with the conductor 560, and the parasitic capacitance is reduced. In addition, the channel forming region and the source / drain region (region 531a and No offset region is formed between region 531a and region 531b. By forming 1b in a self-aligned manner, the on-current is increased and the threshold This allows for reduction of the voltage threshold and improvement of the operating frequency.

[0331] In order to further reduce the off-state current, an off-state current is formed between the channel forming region and the source / drain region. An offset region is a region having a high electrical resistivity, and The offset region is a region where the introduction of the impurity element is not performed. This can be achieved by introducing the impurity element described above after the formation of the insulator 5. The insulating layer 75 functions as a mask in the same manner as the insulating layer 571. Impurity elements are not introduced into the region overlapping with the body 575, and the electrical resistivity of the region remains high. It is possible.

[0332] The transistor 510D also includes an insulator 570, a conductor 560, a metal oxide 552, ... The insulating layer 575 is disposed on the side of the insulating layer 550 and the oxide 530c. It is preferable to use an insulator with a low dielectric constant, such as silicon oxide, silicon oxynitride, Silicon oxynitride, silicon nitride, silicon oxide with fluorine, silicon oxide with carbon silicon, carbon and nitrogen doped silicon oxide, silicon oxide with vacancies, or Resins are preferred. In particular, silicon oxide, silicon oxynitride, silicon nitride oxide, etc. In the latter process, if silicon oxide with vacancies is used as the insulator 575, In addition, silicon oxide and silicon oxynitride are preferable because they can easily form an excess oxygen region. Silicon is preferred because it is thermally stable. Insulator 575 also has the function of diffusing oxygen. It is preferred that the compound has the following structure:

[0333] Also, transistor 510D has insulator 575 and insulator 574 on oxide 530. The insulator 574 is preferably formed by sputtering. By using this method, it is possible to form an insulator film with few impurities such as water or hydrogen. For example, aluminum oxide may be used as the insulator 574.

[0334] In addition, the oxide film formed by the sputtering method may extract hydrogen from the structure on which the film is formed. Therefore, the insulator 574 absorbs hydrogen and water from the oxide 530 and the insulator 575. This allows the hydrogen concentration in the oxide 530 and the insulator 575 to be reduced.

[0335] <Transistor structure example 5> An example of the structure of the transistor 510E will be described with reference to FIGS. 15A to 15C. 15B is a top view of transistor 510E. 15C is a cross-sectional view of the area indicated by the dashed line W1-W2 in FIG. In the top view of FIG. 15A, some elements are omitted for clarity. There are.

[0336] Transistor 510E is a modification of the transistor described above. To prevent this, differences from the above transistor will be mainly described.

[0337] 15A to 15C, the conductor 542 is not provided, and the exposed oxide 530b surface It has a region 531a and a region 531b in part. One acts as a source region and the other acts as a drain region. An insulator 573 is provided between the insulator 574 and the insulator 573 .

[0338] The region 531 (region 531a and region 531b) shown in FIG. 15 is formed by the oxide 530b. The region 531 is a region where the following elements are added to the region 532. For example, a dummy gate is used. It can be formed by

[0339] Specifically, a dummy gate is provided on the oxide 530b, and the dummy gate is used as a mask. It is preferable to use the oxide 530b as a thin film and add an element that reduces the resistance of the oxide 530b. The element is added to the region not overlapping with the dummy gate, forming a region 531. The element is added by mass-separating the ionized source gas. ion implantation, which adds ionized source gas without mass separation; and ion doping, which adds ionized source gas without mass separation. method, plasma immersion ion implantation method, etc. can be used.

[0340] Representative elements that reduce the resistance of the oxide 530 include boron and phosphorus. In addition, hydrogen, carbon, nitrogen, fluorine, sulfur, chlorine, titanium, rare gases, etc. Representative examples of rare gases include helium, neon, argon, krypton, and xenon. The concentration of the element can be measured using SIMS or the like.

[0341] In particular, boron and phosphorus are used in the manufacturing of amorphous silicon or low-temperature polysilicon. This is preferable because existing equipment can be used. Existing facilities can be repurposed. Capital investment can be reduced.

[0342] Next, an insulating film that will become an insulator 573 and a An insulating film to be the insulator 573 and an insulating film to be the insulator 574 may be formed. By laminating an insulating film that becomes the insulating layer 574, the region 531, the oxide 530c, and the insulating layer 574 are An overlapping area with the edge body 550 can be provided.

[0343] Specifically, after forming an insulating film to be the insulator 580 on the insulating film to be the insulator 574, By performing CMP on the insulating film that will become the insulator 580, a part of the insulating film that will become the insulator 580 is The dummy gate is then removed to expose the dummy gate. Therefore, the opening in the insulator 580 The insulators 574 and 573 are exposed on the side of the opening, and the bottom of the opening is covered with an oxide film. A portion of the region 531 formed in the oxide 530b is exposed. The oxide film that becomes 0c, the insulating film that becomes the insulator 550, and the conductive film that becomes the conductor 560 are formed in this order. After the film formation, the insulator 580 is removed by CMP or the like until it is exposed, forming an oxide 530c. The oxide film, the insulating film that will become the insulator 550, and a part of the conductive film that will become the conductor 560 are removed. In this way, the transistor shown in FIG. 15 can be formed.

[0344] The insulators 573 and 574 are not essential components. It can be designed appropriately depending on the starter characteristics.

[0345] The transistor shown in FIG. 15 can be adapted from an existing device and further includes conductor 54 Since there is no need to provide 2, costs can be reduced.

[0346] <Transistor structure example 6> An example of the structure of the transistor 510F will be described with reference to FIGS. 16A to 16C. 16B is a top view of transistor 510F. 16C is a cross-sectional view of the area indicated by the dashed line W1-W2 in FIG. In the top view of FIG. 16A, some elements are omitted for clarity. There are.

[0347] Transistor 510F is a modification of transistor 510A. To avoid confusion, the differences from the above transistor will be mainly described.

[0348] In transistor 510A, a portion of insulator 574 is located within an opening in insulator 580. The transistor 5 is provided so as to cover the side surface of the conductor 560. In 10F, portions of insulator 580 and insulator 574 are removed to form openings.

[0349] In addition, an insulator 576 (insulator) having a barrier property is provided between the conductor 546 and the insulator 580. By providing the insulator 576, The oxygen in the insulator 580 reacts with the conductor 546, and the conductor 546 is prevented from being oxidized. This can be done.

[0350] When an oxide semiconductor is used as the oxide 530, the atomic ratio of each metal atom is different. It is preferable that the oxide 530a has a laminated structure of a plurality of oxide layers. In the metal oxide, the atomic ratio of element M in the constituent elements is It is preferable that the atomic ratio of element M in the constituent elements of the metal oxide is larger than that of element M. In the metal oxide used for the oxide 530a, the atomic ratio of element M to In is It is preferable that the atomic ratio of element M to In in the metal oxide used in 30b is larger than that of element M. In addition, in the metal oxide used for the oxide 530b, the ratio of In atoms to the element M is preferably The atomic ratio of In to element M in the metal oxide used for oxide 530a is It is preferable that the oxide 530c is larger than the oxide 530a or the oxide 530. The metal oxides that can be used for b can be used.

[0351] The oxide 530a, the oxide 530b, and the oxide 530c preferably have crystallinity. It is preferable to use CAAC-OS, and it is particularly preferable to use CAAC-OS. The oxides used have few impurities and defects (oxygen deficiency, etc.), high crystallinity, and a dense structure. Therefore, the source electrode or the drain electrode is not able to extract oxygen from the oxide 530b. This makes it possible to suppress the removal of oxide from the oxide 530b even when heat treatment is performed. Since this reduces the amount of material being pulled out, transistor 510F can be manufactured with high efficiency. It is stable over a wide temperature range (the so-called thermal budget).

[0352] It is to be noted that either or both of the oxide 530a and the oxide 530c may be omitted. The oxide 530 may be a single layer of oxide 530b. In the case of stacking the oxide 530a and oxide 530b and the oxide 530c, The energy of the conduction band minimum of oxide 530c is higher than the energy of the conduction band minimum of oxide 530b. In other words, the electrons of the oxide 530a and the oxide 530c are Preferably, the electron affinity of oxide 530b is smaller than the electron affinity of oxide 530b. It is preferable that the metal oxide used for the oxide 530a is used for the metal oxide 30c. Specifically, in the metal oxide used for the oxide 530c, the atomic ratio of element M in the constituent elements is is greater than the atomic ratio of element M among the constituent elements in the metal oxide used for oxide 530b. In addition, in the metal oxide used for the oxide 530c, the The atomic ratio of element M to In in the metal oxide used for oxide 530b is In addition, in the metal oxide used for the oxide 530b, The atomic ratio of In to element M is It is preferable that the atomic ratio of In to M is larger than that of In.

[0353] Here, at the junctions of oxide 530a, oxide 530b, and oxide 530c, The energy level of the conduction band minimum changes gradually. The energy level of the conduction band minimum at the junction of the oxide 530b and the oxide 530c is It can also be said that the oxide layer is continuously changed or continuously bonded. At the interface between oxide 530a and oxide 530b, and at the interface between oxide 530b and oxide 530c In this case, the defect level density of the mixed layer formed in the step (b) is preferably reduced.

[0354] Specifically, oxide 530a and oxide 530b, and oxide 530b and oxide 530c are By having a common element other than oxygen (as the main component), a mixed layer with low defect level density is formed. For example, when the oxide 530b is an In-Ga-Zn oxide, the oxide 530a and oxide 530c, In-Ga-Zn oxide, Ga-Zn oxide, oxide Alternatively, gallium oxide or the like may be used. The oxide 530c may have a stacked structure. For example, In-Ga-Zn oxide and a stack of Ga-Zn oxide on the In-Ga-Zn oxide structure, or In-Ga-Zn oxide and gallium oxide on the In-Ga-Zn oxide In other words, a laminated structure of In-Ga-Zn oxide and a layer containing In can be used. A stacked structure of an oxide that does not contain the oxide may be used as the oxide 530c.

[0355] Specifically, the oxide 530a has an atomic ratio of In:Ga:Zn=1:3:4. or a metal with a composition of 1:1:0.5 [atomic ratio] or a composition of 1:1:0.5 ... The oxide 530b may be In:Ga:Zn=1:1:1[ In:Ga:Zn=4:2:3 [atomic ratio] or a composition close to that is a composition in the vicinity of In:Ga:Zn=5:1:3 [atomic ratio] or a composition in the vicinity of In:Ga:Zn=5:1:3 [atomic ratio] , or a metal oxide having a composition of 10:1:3 [atomic ratio] or thereabouts, or In Zn oxide can be used as oxide 530a or oxide 530b. The composition in the vicinity of the desired atomic ratio is within ±30% of the desired atomic ratio. Includes:

[0356] The oxide 530c may have a stacked structure of two or more layers. As a specific example of a laminated structure, a lower layer of the oxide 530c is In:Ga:Zn =5:1:3 [atomic ratio] or a composition close to that, or 10:1:3 [atomic ratio] or a metal oxide of a similar composition, or In-Zn oxide, is used, and oxide 530c As the upper layer, In:Ga:Zn=1:3:4 [atomic ratio] or a composition close thereto, G A:Zn=2:1 [atomic ratio] or a composition close to that, or Ga:Zn=2:5 [atomic ratio] The composition may be gallium oxide or a composition having a ratio of 0.1 to 0.25 or a ratio close to that ratio.

[0357] By configuring the oxide 530a and the oxide 530c as described above, the oxide 530a and the oxide The defect density at the interface with oxide 530b and the interface between oxide 530b and oxide 530c Therefore, the influence of interface scattering on carrier conduction is reduced. This allows the transistor 510F to have a high on-state current and high frequency characteristics. When the oxide 530c has a laminated structure, the oxide 530b and the oxide 530c In addition to the effect of lowering the defect level density at the interface with the oxide 530c, It is expected that the oxide is prevented from diffusing into the insulator 550. 530c has a laminated structure, and an oxide that does not contain In is positioned above the laminated structure. The insulator 550 can suppress In that can diffuse to the gate insulator 550 side. Therefore, if In diffuses, the transistor characteristics will be poor. By forming the oxide 530c into a stacked structure, a highly reliable display device can be provided. This becomes:

[0358] The oxide 530 is preferably a metal oxide that functions as an oxide semiconductor. For example, the metal oxide that will be the channel forming region of the oxide 530 is a metal oxide having a band gap of 2. It is preferable to use a vanadium ion beam having an energy of 2.5 eV or more, preferably 2.5 eV or more. By using a metal oxide with a wide band gap, the off-state current of the transistor can be reduced. By using such a transistor, a semiconductor device with low power consumption can be provided. do.

[0359] <Configuration Example 2 of Semiconductor Device> 17 shows a semiconductor device having a conductor 692 on an insulator 650 in the semiconductor device shown in FIG. An example is shown in FIG. 17. A conductor 692 is formed to cover one side of the semiconductor device. Although not shown, the conductor 692 may have an opening. A conductor electrically connected to the electrical current may be provided within the opening.

[0360] A metal can be used as the conductor 692. Also, a metal nitride or a metal having conductivity can be used. The conductor 692 may be made of, for example, titanium, titanium nitride, titanium oxide, etc. The conductor 692 can block electromagnetic waves from the outside more effectively than the semiconductor device. The conductor 692 also has the function of dissipating static electricity or discharging the charge. By providing the conductor 692, the operation of the semiconductor device can be further improved. can be stabilized to.

[0361] FIG. 18 shows an example in which an insulator 693 is provided between an insulator 650 and a conductor 692. The edge body 693 may be, for example, a structure in which a fibrous body is impregnated with an organic resin. The fibrous material may be, for example, glass fiber. The organic resin may be, for example, brominated epoxy resin. A silicone resin may also be used.

[0362] Note that this embodiment mode may be implemented in appropriate combination with other embodiment modes described in this specification. It is possible.

[0363] (Embodiment 3) In this embodiment, the semiconductor device can be used for the OS transistor described in the above embodiment. The structure of the metal oxide will be described.

[0364] <<Metal oxides>> The oxide 530 is preferably a metal oxide that functions as an oxide semiconductor. Metal oxides applicable to the oxide 530 according to the present invention will be described below.

[0365] The metal oxide preferably contains at least indium or zinc. In addition to indium and zinc, gallium is preferably contained. It is preferable that the alloy contains boron, titanium, iron, nickel, or the like. Nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, One or more selected from the group consisting of fluorine, tantalum, tungsten, magnesium, etc. may be included.

[0366] Here, the metal oxide is an In-M-Zn oxide having indium, element M, and zinc. The element M can be aluminum, gallium, yttrium, or is one or more elements selected from tin. Other elements that can be used for element M include ho, Uron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, These include lithium, neodymium, hafnium, tantalum, tungsten, and magnesium. As the element M, a combination of two or more of the above elements may be used.

[0367] In this specification, metal oxides containing nitrogen are also referred to as metal oxides (metal oxides). Metal oxides containing nitrogen are sometimes collectively called metal oxynitrides (metal oxynitrides). It may also be called tal oxynitride.

[0368] [Metal oxide structures] Oxide semiconductors (metal oxides) are classified into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Non-single-crystal oxide semiconductors are, for example, CAAC-OS, polycrystalline nc-OS (nanocrystalline oxide semiconductor) conductor), pseudo-amorphous oxide semiconductor (a-like OS) and amorphous oxide semiconductors There is the body.

[0369] CAAC-OS has a c-axis orientation and multiple nanocrystals are connected in the ab-plane direction. The crystal structure is distorted by the connection of multiple nanocrystals. In the region, the lattice arrangement is changed between a region with a uniform lattice arrangement and another region with a uniform lattice arrangement. This refers to the point where the direction of the

[0370] Nanocrystals are basically hexagonal, but are not limited to regular hexagonal shapes. They may also have non-regular hexagonal shapes. In addition, the distortion may have lattice arrangements such as pentagons and heptagons. In addition, in CAAC-OS, clear grain boundaries (grain bows) are not observed even near the strain. It is difficult to confirm the crystal structure (also called "undary") due to the distortion of the lattice arrangement. This is because the CAAC-OS is aligned in the ab-plane direction. In this case, the arrangement of oxygen atoms is not dense, and the bond distance between atoms is reduced by the substitution of metal elements. This is because distortion can be tolerated by changing the

[0371] In addition, the CAAC-OS has a layer containing indium and oxygen (hereinafter referred to as an In layer) and an elemental A layered crystal consisting of layers containing element M, zinc, and oxygen (hereinafter referred to as the (M,Zn) layer). It is noted that indium and element M tend to have a structure (also called a layered structure). When the element M in the (M,Zn) layer is replaced with indium, the (In,M,Zn) ) layer. Also, when indium in the In layer is replaced with element M, it can be expressed as (In, It can also be expressed as the M layer.

[0372] CAAC-OS is a highly crystalline metal oxide. Since it is difficult to identify grain boundaries, the decrease in electron mobility caused by grain boundaries is unlikely to occur. In addition, the crystallinity of metal oxides can be reduced by the incorporation of impurities or the generation of defects. Therefore, CAAC-OS is a metal oxide with few impurities and defects (such as oxygen vacancies). Therefore, the physical properties of metal oxides with CAAC-OS are stable. Therefore, metal oxides with CAAC-OS are heat-resistant and highly reliable.

[0373] nc-OS is a material that can be used in microscopic areas (e.g., areas between 1 nm and 10 nm, especially areas between 1 nm and 10 nm). The atomic arrangement is periodic in the region of 3 nm or less. There is no regularity in the crystal orientation between the crystals. Therefore, no orientation is observed throughout the film. Therefore, depending on the analytical method, nc-OS may be classified as a-like OS or amorphous oxide semiconductor. It may be indistinguishable from the body.

[0374] In-, a type of metal oxide containing indium, gallium, and zinc, Ga-Zn oxide (hereinafter referred to as IGZO) has a stable structure when made into the nanocrystals mentioned above. In particular, IGZO tends to have difficulty growing crystals in the atmosphere, so large crystals may form. Crystals smaller than the crystals (here, crystals of several mm or crystals of several cm) (for example, the above-mentioned Nanocrystals may be structurally more stable.

[0375] The a-like OS is a metal oxide semiconductor with a structure between the nc-OS and the amorphous oxide semiconductor. The a-like OS has pores or low density regions. The ke-OS has lower crystallinity than the nc-OS and CAAC-OS.

[0376] Oxide semiconductors (metal oxides) have a variety of structures, each with different properties. The oxide semiconductor of one embodiment of the present invention may be an amorphous oxide semiconductor, a polycrystalline oxide semiconductor, an a-li The ke-OS, nc-OS, and CAAC-OS may have two or more of them.

[0377] [impurities] Here, the influence of each impurity in the metal oxide will be described.

[0378] When impurities are mixed into an oxide semiconductor, defect states or oxygen vacancies may be formed. Therefore, when impurities are mixed into the channel formation region of the oxide semiconductor, the oxide semiconductor The electrical characteristics of the transistors used may be easily changed, resulting in poor reliability. If the channel formation region contains oxygen vacancies, the transistor will have normally-on characteristics. Cheap.

[0379] The defect levels may include trap levels. Charges trapped in the levels take a long time to disappear, and they act as if they are fixed charges. Therefore, metal oxide with high trap state density is used in the channel formation region. A transistor having such a structure may have unstable electrical characteristics.

[0380] Furthermore, if impurities exist in the channel formation region of the oxide semiconductor, the The crystallinity of the oxide provided in contact with the channel forming region may be reduced. If the crystallinity of the channel formation region is low, the stability or In addition, the reliability tends to deteriorate. Poor crystallinity can lead to the formation of interface states, which can deteriorate the stability or reliability of transistors. There is.

[0381] Therefore, in order to improve the stability or reliability of a transistor, it is necessary to use an oxide semiconductor transistor. It is effective to reduce the impurity concentration in the channel forming region and its vicinity. The elements include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, silicon, etc.

[0382] Specifically, SIMS is performed on the channel formation region of the oxide semiconductor and its vicinity. The concentration of the above impurities obtained by 18 atoms / cm 3 Below, preferably 2×10 16 atoms / cm 3 Alternatively, a channel of the oxide semiconductor may be formed as follows. The concentration of the above impurities obtained by elemental analysis using EDX in the region and its vicinity The oxide semiconductor is an oxide semiconductor containing element M. When an element M is used, the element M is contained in the channel formation region of the oxide semiconductor and in the vicinity thereof. The concentration ratio of the impurities to the The concentration of element M used in calculating the concentration ratio is the region where the concentration of the impurity is calculated. The concentration may be the concentration in the same region or the concentration in the oxide semiconductor.

[0383] In addition, metal oxides with reduced impurity concentrations have a low defect level density, so the trap level density is The degree may also be lower.

[0384] In addition, when hydrogen enters an oxygen vacancy in a metal oxide, the oxygen vacancy and hydrogen bond to form V O H V O H acts as a donor, and electrons are generated as carriers. In addition, some of the hydrogen atoms may bond with oxygen atoms that bond with metal atoms, forming electron carriers. May create children.

[0385] Therefore, a transistor using an oxide semiconductor containing a large amount of hydrogen has a normally-on In addition, hydrogen in the oxide semiconductor is easily degraded by stress such as heat or an electric field. Because hydrogen is easily mobile, the reliability of transistors deteriorates when a large amount of hydrogen is contained in an oxide semiconductor. There is also a risk that this may happen.

[0386] That is, V in metal oxides O Reduce H as much as possible and use high-purity intrinsic or substantially high-purity It is preferable to make it intrinsic. O To obtain an oxide semiconductor with sufficiently reduced H, The process involves removing impurities such as moisture and hydrogen from the oxide semiconductor (referred to as dehydration and dehydrogenation treatment). and supplying oxygen to the oxide semiconductor to compensate for oxygen vacancies (oxygen addition). (sometimes referred to as chemical treatment) is important. O Acid with sufficiently reduced impurities such as H By using a compound semiconductor in the channel formation region of a transistor, stable electrical characteristics are achieved. It is possible.

[0387] In addition, an oxide semiconductor with a low carrier concentration is preferably used for the transistor. When the carrier concentration of an oxide semiconductor is reduced, the impurity concentration in the oxide semiconductor is reduced. In this specification and the like, the impurity concentration is low and the defect level density is low. A low level density is called a highly pure intrinsic or substantially highly pure intrinsic oxide semiconductor. Impurities in the steel include, for example, hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, There are Kel, silicon, etc.

[0388] In particular, hydrogen contained in oxide semiconductors reacts with oxygen that bonds with metal atoms to form water. Therefore, oxygen vacancies may be formed in the oxide semiconductor. If oxygen vacancies are present in the region, the transistor may exhibit normally-on characteristics. Furthermore, defects where hydrogen has entered the oxygen vacancies function as donors, generating electrons as carriers. In addition, some of the hydrogen atoms may bond with oxygen atoms that bond with metal atoms, forming carriers. Therefore, the hydrogen-rich oxide semiconductor The transistor tends to have normally-on characteristics.

[0389] A defect where hydrogen has entered an oxygen vacancy (V O H) can function as a donor in the oxide semiconductor. However, it is difficult to quantitatively evaluate the defects. In some cases, the carrier concentration is used for evaluation, not the donor concentration. In the literature, the parameter of oxide semiconductors is not the donor concentration but the condition when no electric field is applied. In other words, the "carrier concentration" described in this specification etc. "Donor concentration" can sometimes be rephrased as "donor concentration."

[0390] Therefore, it is preferable that the amount of hydrogen in the oxide semiconductor be reduced as much as possible. is the hydrogen concentration obtained by SIMS in an oxide semiconductor, 1×10 20 atom s / cm 3 Less than 1 x 10 19 atoms / cm 3 less than, more preferably 5x 10 18 atoms / cm 3 less than 1×10 18 atoms / cm 3 Not yet An oxide semiconductor in which impurities such as hydrogen are sufficiently reduced is used as a channel of a transistor. By using it in the formation region, stable electrical characteristics can be imparted.

[0391] The carrier concentration of the oxide semiconductor in the channel formation region is 1×10 18 cm -3 below Preferably, it is 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 Being less than More preferably, 1 × 10 12 cm -3 It is more preferable that the channel The lower limit of the carrier concentration of the oxide semiconductor in the hole formation region is not particularly limited. 1×10 -9 cm -3 It can be said that:

[0392] According to one embodiment of the present invention, a highly reliable semiconductor device can be provided. According to one embodiment of the present invention, a semiconductor device having favorable electrical characteristics can be provided. According to one embodiment of the present invention, a semiconductor device with large on-state current can be provided. According to one embodiment of the present invention, a semiconductor device that can be miniaturized or highly integrated can be provided. Another object of one embodiment of the present invention is to provide a semiconductor device with low power consumption. do.

[0393] <<Other semiconductor materials>> The semiconductor materials that can be used for the oxide 530 are not limited to the above-mentioned metal oxides. As the compound 530, a semiconductor material having a band gap (a semiconductor that is not a zero-gap semiconductor) For example, semiconductors of simple elements such as silicon, gallium arsenide, etc. Compound semiconductors, layered materials (also called atomic layer materials, two-dimensional materials, etc.) that function as semiconductors It is preferable to use a layered material that functions as a semiconductor. It is suitable for use in semiconductor materials.

[0394] In this specification, the term "layered material" is a general term for a group of materials having a layered crystal structure. The layered crystal structure is formed by covalent and ionic bonds, and the layers are The structure is made up of layers of molecules that are stacked via bonds weaker than covalent or ionic bonds, such as ionic bonds. Layered materials have high electrical conductivity within the unit layer, that is, high two-dimensional electrical conductivity. A material that functions as a semiconductor and has high two-dimensional electrical conductivity is used for the channel formation region. This makes it possible to provide a transistor with a large on-state current.

[0395] Layered materials include graphene, silicene, and chalcogenides. is a compound containing chalcogen. Chalcogen is also a general term for elements belonging to Group 16. and includes oxygen, sulfur, selenium, tellurium, polonium, and livermorium. Examples of chalcogenides include transition metal chalcogenides and group 13 chalcogenides. .

[0396] The oxide 530 may be, for example, a transition metal chalcogenide that functions as a semiconductor. Specific examples of transition metal chalcogenides that can be used as the oxide 530 include: These include molybdenum sulfide (typically MoS2), molybdenum selenide (typically MoS e2), molybdenum telluride (typically MoTe2), tungsten sulfide (typically W S2), tungsten selenide (typically WSe2), tungsten telluride (typically is WTe2), hafnium sulfide (typically HfS2), hafnium selenide (typically HfSe2), zirconium sulfide (typically ZrS2), zirconium selenide (typically Typical examples include ZrSe2).

[0397] Note that this embodiment mode may be implemented in appropriate combination with other embodiment modes described in this specification. It is possible. [Explanation of symbols]

[0398] EN1: Terminal, ID1: Current, IN2: Terminal, ND1: Node, ND2: Node, ND3 : Node, ND4: Node, OU1: Terminal, OU2: Terminal, OU3: Terminal, OU4: Terminal , RL1: Resistor element, SG1: Terminal, SH1: Terminal, SH2: Terminal, Sv1: Signal, VB I1: terminal, VD1: wiring, VS1: wiring, VT1: terminal, 21: semiconductor device, 30: generator Oscillator, 31: circuit, 32: circuit, 33: circuit, 36: amplifier circuit, 38: control circuit, 41: Transistor, 42: Transistor, 43: Transistor, 44: Transistor, 45: Transistor, 46a: transistor, 46b: transistor, 47a: transistor, 47b: transistor, 48: transistor, 49: transistor, 51: capacitance element, 5 2: Capacitor element, 53: Inverter, 54: Transistor, 55: Transistor, 56: Comparator, 57: Capacitor element, 61: Transistor, 62: Transistor, 63: Circuit, 63a: transistor, 63b: transistor, 63n: transistor, 63x: circuit, 63y: circuit, 64: transistor, 65: transistor, 66: capacitance element, 71: transistor 72: transistor, 73: transistor, 74: transistor, 75: transistor 76:Transistor, 77:Transistor, 121:Secondary battery, 300:Transistor transistor, 311: substrate, 313: semiconductor region, 314a: low resistance region, 314b: low resistance region Resistance region, 315: insulator, 316: conductor, 320: insulator, 322: insulator, 324: Insulator, 326: Insulator, 328: Conductor, 330: Conductor, 350: Insulator, 352: Insulator, 354: Insulator, 356: Conductor, 360: Insulator, 362: Insulator, 364: Insulator, 366: Conductor, 370: Insulator, 372: Insulator, 374: Insulator, 376: Conductor, 380: Insulator, 382: Insulator, 384: Insulator, 386: Conductor, 500: Transistor, 503: conductor, 503a: conductor, 503b: conductor, 505: conductor , 505a: conductor, 505b: conductor, 510: insulator, 510A: transistor, 5 10B: transistor, 510C: transistor, 510D: transistor, 510E: Transistor, 510F: transistor, 511: insulator, 512: insulator, 514: insulator Insulator, 516: Insulator, 518: Conductor, 520: Insulator, 521: Insulator, 522: Insulator Insulator, 524: Insulator, 530: Oxide, 530a: Oxide, 530b: Oxide, 530 c: oxide, 531: region, 531a: region, 531b: region, 540a: conductor, 54 0b: conductor, 542: conductor, 542a: conductor, 542b: conductor, 543: area, 543a: region, 543b: region, 544: insulator, 545: insulator, 546: conductor, 546a: conductor, 546b: conductor, 547: conductor, 547a: conductor, 547b: Conductor, 548: Conductor, 550: Insulator, 552: Metal oxide, 560: Conductor, 56 0a: conductor, 560b: conductor, 570: insulator, 571: insulator, 573: insulator, 574: Insulator, 575: Insulator, 576: Insulator, 576a: Insulator, 576b: Insulator body, 580: insulator, 581: insulator, 582: insulator, 584: insulator, 586: insulator 600: Capacitor element; 610: Conductor; 612: Conductor; 620: Conductor; 630: Insulator Insulator, 650: Insulator, 692: Conductor, 693: Insulator

Claims

[Claim 1] a first transistor, an oscillator, a first circuit, and a first wiring; the first transistor has a metal oxide containing indium or zinc in a channel formation region; the oscillator includes a second transistor, a third transistor, a fourth transistor, a fifth transistor, and a first capacitive element; a gate of the second transistor and a gate of the third transistor are electrically connected to one of the source and the drain of the first transistor; one of a source and a drain of the second transistor is electrically connected to one of a source and a drain of the fourth transistor and to one electrode of the first capacitor element; one of a source and a drain of the third transistor is electrically connected to one of a source and a drain of the fifth transistor and to the other electrode of the first capacitance element; the other of the source and the drain of the fourth transistor is electrically connected to the gate of the fifth transistor; the other of the source and the drain of the fifth transistor is electrically connected to the first circuit and the gate of the fourth transistor; the first wiring is electrically connected to the other of the source and the drain of the second transistor and the other of the source and the drain of the third transistor; a first potential is applied to a gate of the second transistor and a gate of the third transistor by turning on the first transistor; a function of holding the first potential applied to the gate of the second transistor and the gate of the third transistor by turning off the first transistor; the oscillator has a function of providing a first signal corresponding to the first potential to the first circuit; The first circuit is a semiconductor device having a function of at least one of shaping and amplifying the first signal.

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