JP7222657B2 - Remaining battery level measurement circuit - Google Patents

Description

One aspect of the present invention relates to an article, method, or manufacturing method. Alternatively, the invention relates to a process, machine, manufacture, or composition of matter. One embodiment of the present invention relates to a method for manufacturing a semiconductor device, a display device, a light-emitting device, a power storage device, a lighting device, or an electronic device. In particular, the present invention relates to a charging control system, a charging control method, and an electronic device having a secondary battery. One aspect of the present invention relates to a vehicle or a vehicle electronic device provided in the vehicle.

Note that in this specification, a power storage device generally refers to elements and devices having a power storage function. For example, storage batteries such as lithium ion secondary batteries (also referred to as secondary batteries), lithium ion capacitors, all-solid-state batteries, electric double layer capacitors, and the like are included.

In recent years, various power storage devices such as lithium ion secondary batteries, lithium ion capacitors, and air batteries have been actively developed. In particular, lithium-ion secondary batteries, which have high output and high energy density, are used in portable information terminals such as mobile phones, smart phones, tablets, or notebook computers, portable music players, digital cameras, medical equipment, or hybrid vehicles (HEV). , electric vehicles (EV), and next-generation clean energy vehicles such as plug-in hybrid vehicles (PHEV). It has become an indispensable part of the modernized society.

Patent Literature 1 shows an example of using a neural network to calculate the remaining capacity of a secondary battery.

Conventionally, various proposals have been made as techniques for measuring the remaining amount of a battery. For example, the impedance track method is used to estimate the open-circuit voltage by measuring the internal impedance of the battery. The impedance track method consumes power when measuring the impedance of a battery. In addition, a coulomb counter method and a voltage measurement method are also known as techniques for measuring the remaining amount of a battery.

U.S. Patent Publication No. 2006/0181245

Lithium ion secondary batteries have a ratio of the remaining capacity (RC) of the battery to the full charge capacity (FCC (Full Charge Capacity)) of the design capacity (DC), that is, the charging rate (SOC) is 0% to 100%. It is not set to use all of them, and a margin of about 5% (or 10%) is taken from 0% to prevent overdischarge. Also, in order to prevent overcharging, a margin of about 5% (or 10%) is taken from 100%, and as a result, the design capacity is within the range of 5% to 95% (or 10% to 90%). ) is said to be used in Actually, by setting the voltage range of the upper limit voltage V _max and the lower limit voltage V _min using a BMS (Battery Management System) connected to the secondary battery, the design capacity is within the range of 5% to 95% (or 10 % to 90%).

Secondary batteries deteriorate due to use, aging, and temperature changes. To manage a secondary battery by accurately knowing the internal state of the secondary battery, especially the SOC (state of charge). By accurately knowing the SOC, it is also possible to widen the voltage range between the upper limit voltage _Vmax and the lower limit voltage _Vmin .

A novel battery fuel gauging circuit is provided herein for estimating the dischargeable capacity of a battery. Another issue is to realize the remaining battery level measurement circuit with a simple circuit.

In order to solve the above problems, a voltage measurement method is used. Using the voltage charged in the lithium ion secondary battery (open circuit voltage), the voltage corresponding to the percentage of the remaining amount is written in the storage means, and the voltage discharged from the lithium ion secondary battery and the voltage written in the storage means The remaining capacity is indicated by comparing the voltage with a comparison circuit (comparator circuit, etc.).

One of the configurations of the invention disclosed in this specification is a remaining amount measuring circuit having a display circuit for displaying the remaining amount of the secondary battery, measuring means for measuring the voltage value of the output terminal of the secondary battery, It has a plurality of storage means including transistors each having an oxide semiconductor as a semiconductor layer, and a comparison circuit that compares the voltage values stored in the plurality of storage means with the voltage value obtained by the measurement means.

In addition, a level shifter circuit may be provided, and the configuration is a remaining amount measuring circuit having a display circuit for displaying the remaining amount of the secondary battery, and measuring means for measuring the voltage value of the output terminal of the secondary battery. a plurality of memory means including transistors having oxide semiconductor as a semiconductor layer; a comparison circuit for comparing the voltage values stored in the plurality of memory means with the voltage value obtained by the measuring means; and a memory means. It has a level shifter circuit between it and the comparison circuit.

In the above structure, the memory means has a function of holding an analog signal and includes a transistor including an oxide semiconductor as a semiconductor layer. A simple remaining battery level measuring circuit can be realized by using a transistor having an oxide semiconductor as a semiconductor layer. In the above configuration, the plurality of storage means hold different analog signals generated by resistive voltage division.

The remaining capacity of the secondary battery can be detected according to the number of storage means used, for example, 20%, 30%, 40%, 50%, 60%, 70%, and 80%, respectively. Just do it. When the memory means for 20% is prepared, the capacity of 20% is discriminated by a comparison circuit which compares with the externally controlled voltage. It is expressed as a percentage (%) with respect to the capacity of the lithium ion secondary battery, which is 100% when fully charged and 0% when the final discharge voltage is reached.

It is possible to realize a battery level measuring circuit that can accurately grasp the state of a lithium ion secondary battery.

1 is an example of a circuit diagram illustrating one embodiment of the present invention; FIG. 4 is a graph showing one aspect of the present invention; 1 is an example of a circuit diagram illustrating one embodiment of the present invention; FIG. 1A and 1B are an example of a timing chart and a block diagram illustrating one embodiment of the present invention; 1 is an example of a circuit diagram illustrating one embodiment of the present invention; FIG. FIG. 4 is a diagram illustrating a circuit configuration example of a memory; 1 is a cross-sectional view showing a configuration example of a semiconductor device; FIG. 1 is a cross-sectional view showing a configuration example of a semiconductor device; FIG. 1A and 1B are a top view and a cross-sectional view illustrating a structure example of a transistor; It is a figure explaining a cylindrical secondary battery. It is a figure explaining a secondary battery. It is a figure explaining a secondary battery. It is a figure explaining a secondary battery. It is a figure explaining a secondary battery. It is a figure which shows an example of an electronic device. A diagram explaining the market image.

Embodiments of the present invention will be described in detail below with reference to the drawings. However, those skilled in the art will easily understand that the present invention is not limited to the following description, and that the forms and details thereof can be variously changed. Moreover, the present invention should not be construed as being limited to the description of the embodiments shown below.

(Embodiment 1)
In this embodiment, the battery remaining amount measuring circuit shown in FIG. 1 realizes a display of the remaining amount of the secondary battery in five levels of 0%, 20%, 40%, 60%, and 80%.

The remaining battery capacity measurement circuit shown in FIG. 1 calculates the remaining capacity by the drop in open circuit voltage. Using the voltage (open-circuit voltage) charged in the lithium-ion secondary battery, the voltage corresponding to the percentage of the remaining amount is written in the memory, and the voltage discharged from the lithium-ion secondary battery and the voltage written in the memory are compared. By comparing with , the remaining amount is indicated.

The voltage value (open-circuit voltage) after charging is divided to generate input terminal voltages IN1, IN2, IN3, IN4, and IN5, which are stored in respective memories. In this embodiment mode, the control signal P is input to the gate of the transistor and an analog value is written in the memory at the same time. The input terminal voltage IN5 may be generated from the input terminal voltage IN1 by an external device or a control circuit. Also, the input terminal voltage IN5 may be generated from the input terminal voltage IN1 by resistance voltage division.

Further, FIG. 2 shows discharge curves, and sets input terminal voltages IN1, IN2, IN3, IN4, and IN5, respectively. The input terminal voltages IN1, IN2, IN3, IN4 and IN5 are set between the overdischarge voltage and the overcharge voltage.

For example, if the voltage (open circuit voltage) of the lithium ion secondary battery is higher than the input terminal voltage IN1, the remaining capacity of the lithium ion secondary battery can be said to be 80% or more.

It should be noted that the voltage discharged from the lithium ion secondary battery assumes no load. If the voltage of the lithium-ion battery drops due to the load current, an error may occur in the remaining capacity. Therefore, it is preferable to determine the remaining amount in the no-load state.

Obtaining the difference between the voltage values with no load and with load allows the voltage written in the memory to fluctuate by the difference, thereby preventing an error in the remaining amount. As a configuration in which only the difference is varied, a case in which the voltage value of the memory is varied using a level shifter circuit, and a case in which the opposite polarity of the capacitance is shifted are conceivable.

FIG. 5 shows an example in which a level shifter circuit is provided between the comparator and the memory in order to measure the remaining amount according to the current load. The value stored in the memory is changed by the level shifter circuit. FIG. 5 shows a case where IN1, IN2, IN3, IN4, and IN5 are generated by resistive voltage division. When each input data is generated by resistive voltage division, a battery remaining amount measuring circuit can be configured with a simple circuit.

As another example, FIGS. 3 and 4 show an example in which analog values are sequentially input to the memory using control signals P1, P2, P3, P4, and P5 output from the control circuit 11. FIG. By holding analog values in the memory shown in FIG. 6, it is possible to hold them for a long time. The memory illustrated in FIG. 6 includes a transistor including an oxide semiconductor, and the leakage current of the transistor is extremely low; therefore, the capacity can be retained for a long time.

FIG. 4A shows an example of a timing chart. Analog values to be written in each memory may be generated using a D/A converter as shown in the block diagram of FIG. 4B. By using an A/D converter or a D/A converter, noise can be reduced and the remaining amount can be accurately detected.

In this embodiment, an example of using five memories and five comparators is shown, but it goes without saying that the present invention is not particularly limited. For example, 10 or more may be used to finely display the remaining amount.

(Embodiment 2)
In this embodiment mode, an example of the structure of the memory shown in FIG. 1 is shown. Examples of circuit structures that can be used for memories are shown in FIGS. Each of FIGS. 6A to 6G functions as a memory element. A circuit including this memory circuit or a battery control system is sometimes called a BTOS (battery operating system or battery oxide semiconductor). A memory element 410 illustrated in FIG. 6A includes a transistor M1 and a capacitor CA. A memory element 410 is a memory element including one transistor and one capacitor.

The transistor M1 has a first terminal connected to the first terminal of the capacitor CA, a second terminal connected to the wiring BL, a gate connected to the wiring WL, and a back gate of the transistor M1. are connected to the wiring BGL. A second terminal of the capacitive element CA is connected to the wiring CAL. A node at which the first terminal of the transistor M1 and the first terminal of the capacitor CA are electrically connected is called a node ND.

In an actual transistor, a gate and a back gate are provided so as to overlap with each other with a channel formation region of a semiconductor layer interposed therebetween. Both gates and back gates can function as gates. Therefore, when one is called a "back gate", the other is sometimes called a "gate" or a "front gate". Also, one may be referred to as a "first gate" and the other as a "second gate".

The back gate may have the same potential as the gate, or may have the ground potential or any potential. In addition, the threshold voltage of the transistor can be changed by changing the potential of the back gate independently of the potential of the gate.

By providing the back gate and further by setting the gate and the back gate to the same potential, the region in which carriers flow in the semiconductor layer becomes larger in the film thickness direction, so that the movement amount of carriers increases. As a result, the ON current of the transistor increases and the field effect mobility increases.

Therefore, the transistor can be a transistor having a large on-current with respect to the occupied area. That is, the area occupied by the transistor can be reduced with respect to the required on-current. Therefore, a highly integrated semiconductor device can be realized.

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

Data is written and read by applying a high-level potential to the wiring WL, turning on the transistor M1, and electrically connecting the wiring BL and the node ND.

The wiring CAL functions as a wiring for applying a predetermined potential to the second terminal of the capacitor CA. A fixed potential is preferably applied to the wiring CAL.

A memory element 420 illustrated in FIG. 6B is a modification of the memory element 410 . In the memory element 420, the back gate of the transistor M1 is electrically connected to the wiring WL. With such a structure, the same potential as that of the gate of the transistor M1 can be applied to the back gate of the transistor M1. Therefore, the current flowing through the transistor M1 can be increased when the transistor M1 is in a conducting state.

Alternatively, the transistor M1 may be a single-gate transistor (a transistor without a back gate) as in the memory element 430 illustrated in FIG. 6C. The memory element 430 has a structure in which the back gate is removed from the transistors M1 of the memory elements 410 and 420 . Therefore, the manufacturing process of the memory element 430 can be shorter than that of the memory elements 410 and 420 .

Storage element 410, storage element 420, and storage element 430 are DRAM-type storage elements.

An oxide semiconductor is preferably used for the semiconductor layer in which the channel of the transistor M1 is formed. In this specification and the like, a transistor including an oxide semiconductor in a semiconductor layer in which a channel is formed is also referred to as an “OS transistor”.

For example, as an oxide semiconductor, indium, element M (element M is aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, One or more selected from tantalum, tungsten, magnesium, etc.) and zinc can be used. In particular, the oxide semiconductor preferably contains indium, gallium, and zinc.

An OS transistor has a characteristic of extremely low off-state current. By using an OS transistor as the transistor M1, leakage current of the transistor M1 can be significantly reduced. That is, written data can be held for a long time by the transistor M1. Therefore, the refresh frequency of the memory element can be reduced. In addition, the refresh operation of the memory element can be made unnecessary. In addition, since leakage current is extremely low, multilevel data or analog data can be held in the memory elements 410, 420, and 430. FIG.

In this specification and the like, a DRAM using an OS transistor is referred to as a DOSRAM (Dynamic Oxide Semiconductor Random Access Memory).

FIG. 6D shows a circuit configuration example of a gain-cell memory element including two transistors and one capacitor. The memory element 440 includes a transistor M1, a transistor M2, and a capacitor CA.

A first terminal of the transistor M1 is connected to the first terminal of the capacitor CA, a second terminal of the transistor M1 is connected to the wiring WBL, and a gate of the transistor M1 is connected to the wiring WWL. A second terminal of the capacitive element CA is connected to the wiring CAL. A first terminal of the transistor M2 is connected to the wiring RBL, a second terminal of the transistor M2 is connected to the wiring RWL, and a gate of the transistor M2 is connected to the first terminal of the capacitor CA. A node at which the first terminal of the transistor M1, the first terminal of the capacitor CA, and the gate of the transistor M2 are electrically connected is called a node ND.

Bit line WBL functions as a write bit line, bit line RBL functions as a read bit line, word line WWL functions as a write word line, and word line RWL functions as a read word line. Transistor M1 functions as a switch that makes the node ND and bit line WBL conductive or non-conductive.

An OS transistor is preferably used as the transistor M1. As described above, the off-state current of the OS transistor is very low; therefore, by using the OS transistor as the transistor M1, the potential written to the node ND can be held for a long time. In other words, data written in the memory element can be held for a long time.

There is no particular limitation on the transistor used for the transistor M2. As the transistor M2, an OS transistor, a Si transistor (a transistor using silicon for a semiconductor layer), or another transistor may be used.

Note that when a Si transistor is used as the transistor M2, silicon used for the semiconductor layer may be amorphous silicon, polycrystalline silicon, low temperature polysilicon (LTPS), or single crystal silicon. A Si transistor may have a higher field-effect mobility than an OS transistor. Therefore, if a Si transistor is used as a reading transistor, the operation speed during reading can be increased.

When an OS transistor is used as the transistor M1 and a Si transistor is used as the transistor M2, both may be stacked in different layers. An OS transistor can be manufactured using a manufacturing apparatus and a process similar to those of a Si transistor. Therefore, mixed mounting (hybridization) of an OS transistor and a Si transistor is easy, and high integration is also easy.

In addition, when an OS transistor is used as the transistor M2, leakage current when not selected can be significantly reduced, so that reading accuracy can be improved. By using OS transistors for both the transistor M1 and the transistor M2, the number of steps for manufacturing a semiconductor device can be reduced, and productivity can be improved. For example, a semiconductor device can be manufactured at a process temperature of 400° C. or lower.

FIGS. 6E to 6G show circuit configuration examples in which transistors having back gates (four-terminal transistors; also referred to as “four-terminal elements”) are used for the transistors M1 and M2. A memory element 450 illustrated in FIG. 6E, a memory element 460 illustrated in FIG. 6F, and a memory element 470 illustrated in FIG.

In the memory element 450 illustrated in FIG. 6E, the gate and back gate of the transistor M1 are electrically connected. Also, the gate and back gate of the transistor M2 are electrically connected.

In the memory element 460 illustrated in FIG. 6F, the back gate of the transistor M1 and the back gate of the transistor M2 are electrically connected to the wiring BGL. A predetermined potential can be applied to the back gates of the transistor M1 and the transistor M2 through the wiring BGL.

In the memory element 470 illustrated in FIG. 6G, the back gate of the transistor M1 is electrically connected to the wiring WBGL, and the back gate of the transistor M2 is electrically connected to the wiring RBGL. By connecting the back gate of the transistor M1 and the back gate of the transistor M2 to different wirings, the threshold voltages can be changed independently.

The memory elements 440 to 470 are 2Tr1C memory cells. In this specification and the like, a memory device in which a 2Tr1C memory cell is formed by using an OS transistor as the transistor M1 is called a NOSRAM (Non-volatile Oxide Semiconductor Random Access Memory). Further, in the memory elements 440 to 470, the potential of the node ND can be amplified by the transistor M12 and read. In addition, since the OS transistor has very low off-state current, the potential of the node ND can be held for a long time. In addition, nondestructive reading can be performed in which the potential of the node ND is held even when a reading operation is performed.

Information held in the memory element 101 is information that is infrequently rewritten. Therefore, as the storage element 101, it is preferable to use a NOSRAM that can read information nondestructively and retain information for a long period of time.

Further, since the transistors shown in FIGS. 6A, 6B, and 6E to 6G are four-terminal elements, they are MRAM (Magnetoresistive Random Access Memory) utilizing MTJ (Magnetic Tunnel Junction) characteristics. Compared with a two-terminal element represented by ReRAM (Resistive Random Access Memory), Phase-change memory, etc., it has the feature that input/output can be easily controlled independently.

In addition, MRAM, ReRAM, and phase change memory may undergo structural changes at the atomic level when information is rewritten. On the other hand, since the memory device of one embodiment of the present invention operates by charging or discharging electric charges through a transistor when data is rewritten, it has characteristics such as excellent resistance to repetitive rewriting and little structural change.

This embodiment can be freely combined with other embodiments.

(Embodiment 3)
In this embodiment, a structure of a transistor which can be applied to the structure of the memory element described in the above embodiment, specifically, a structure in which transistors having different electrical characteristics are stacked will be described. In particular, in this embodiment mode, a structure of each transistor included in a memory circuit included in a semiconductor device will be described. With such a structure, the degree of freedom in designing the semiconductor device can be increased. In addition, by stacking transistors having different electrical characteristics, the degree of integration of the semiconductor device can be increased.

A semiconductor device illustrated in FIG. 7 includes a transistor 300 , a transistor 500 , and a capacitor 600 . 9A is a cross-sectional view of the transistor 500 in the channel length direction, FIG. 9B is a cross-sectional view of the transistor 500 in the channel width direction, and FIG. 9C is a cross-sectional view of the transistor 300 in the channel width direction. It is a diagram.

The transistor 500 is a transistor (OS transistor) including an oxide semiconductor in a channel formation region. Since the transistor 500 has a low off-state current, by using the transistor 500 as an OS transistor included in the semiconductor device, written data voltage or electric charge can be held for a long time. In other words, the power consumption of the semiconductor device can be reduced because the frequency of the refresh operation is low or the refresh operation is not required.

The semiconductor device described in this embodiment includes a transistor 300, a transistor 500, and a capacitor 600 as illustrated in FIG. The transistor 500 is provided above the transistor 300 , and the capacitor 600 is provided above the transistors 300 and 500 . Note that the capacitor 600 can be a capacitor Cs or the like in a memory circuit.

The transistor 300 is provided over a substrate 311 and has a conductor 316, an insulator 315, a semiconductor region 313 made of part of the substrate 311, and low-resistance regions 314a and 314b functioning as source or drain regions. . Note that the transistor 300 can be applied to, for example, the transistor included in the memory circuit in any of the above embodiments.

In the transistor 300, as shown in FIG. 9C, a top surface and side surfaces in the channel width direction of a semiconductor region 313 are covered with a conductor 316 with an insulator 315 interposed therebetween. By making the transistor 300 Fin-type in this manner, the effective channel width is increased, so that the on-characteristics of the transistor 300 can be improved. Further, since the contribution of the electric field of the gate electrode can be increased, the off characteristics of the transistor 300 can be improved.

Note that the transistor 300 may be of either p-channel type or n-channel type.

A region in which a channel of the semiconductor region 313 is formed, a region in the vicinity thereof, the low-resistance regions 314a and 314b serving as a source region or a drain region, and the like preferably contain a semiconductor such as a silicon-based semiconductor. It preferably contains crystalline silicon. Alternatively, a material including Ge (germanium), SiGe (silicon germanium), GaAs (gallium arsenide), GaAlAs (gallium aluminum arsenide), or the like may be used. A structure using silicon in which the effective mass is controlled by applying stress to the crystal lattice and changing the lattice spacing may be used. Alternatively, the transistor 300 may be a HEMT (High Electron Mobility Transistor) by using GaAs, GaAlAs, or the like.

In the low-resistance regions 314a and 314b, in addition to the semiconductor material applied to the semiconductor region 313, an element imparting n-type conductivity, such as arsenic or phosphorus, or an element imparting p-type conductivity, such as boron, is used. contains elements that

The conductor 316 functioning as a gate electrode is a semiconductor material such as silicon containing an element imparting n-type conductivity such as arsenic or phosphorus or an element imparting p-type conductivity such as boron, a metal material, or an alloy. material, or a conductive material such as a metal oxide material.

Note that since the work function is determined by the material of the conductor, the threshold voltage of the transistor can be adjusted by selecting the material of the conductor. Specifically, it is preferable to use a material such as titanium nitride or tantalum nitride for the conductor. Furthermore, in order to achieve both conductivity and embeddability, it is preferable to use a metal material such as tungsten or aluminum as a laminate for the conductor, and it is particularly preferable to use tungsten from the viewpoint of heat resistance.

Note that the transistor 300 illustrated in FIG. 7 is an example, and the structure thereof is not limited, and an appropriate transistor may be used depending on the circuit configuration and the driving method. For example, in the case where the semiconductor device is a unipolar circuit including only an OS transistor (meaning a transistor with the same polarity as only an n-channel transistor), the transistor 300 is formed using an oxide semiconductor as illustrated in FIG. A structure similar to that of the transistor 500 may be used. Details of the transistor 500 will be described later.

An insulator 320 , an insulator 322 , an insulator 324 , and an insulator 326 are stacked in order to cover the transistor 300 .

For the insulators 320, 322, 324, and 326, for example, silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum nitride oxide, aluminum nitride, or the like is used. Just do it.

In this specification, silicon oxynitride refers to a material whose composition contains more oxygen than nitrogen, and silicon oxynitride refers to a material whose composition contains more nitrogen than oxygen. indicates In this specification, aluminum oxynitride refers to a material whose composition contains more oxygen than nitrogen, and aluminum oxynitride refers to a material whose composition contains more nitrogen than oxygen. indicates

The insulator 322 may function as a planarization film that planarizes a step caused by the transistor 300 or the like provided therebelow. For example, the top surface of the insulator 322 may be planarized by a chemical mechanical polishing (CMP) method or the like to improve planarity.

For the insulator 324, it is preferable to use a film having a barrier property such that hydrogen or impurities do not diffuse from the substrate 311, the transistor 300, or the like to the region where the transistor 500 is provided.

As an example of a film having a barrier property against hydrogen, silicon nitride formed by a CVD method can be used. Here, diffusion of hydrogen into a semiconductor element including an oxide semiconductor, such as the transistor 500, might degrade the characteristics of the semiconductor element. Therefore, it is preferable to use a film that suppresses diffusion of hydrogen between the transistor 500 and the transistor 300 . Specifically, the film that suppresses diffusion of hydrogen is a film from which the amount of desorption of hydrogen is small.

The desorption amount of hydrogen can be analyzed using, for example, thermal desorption spectroscopy (TDS). For example, the amount of hydrogen released from the insulator 324 is the amount of hydrogen atoms released per area of the insulator 324 when the surface temperature of the film is in the range of 50° C. to 500° C. in TDS analysis. , 10×10 ¹⁵ atoms/cm ² or less, preferably 5×10 ¹⁵ atoms/cm ² or less.

Note that the insulator 326 preferably has a lower dielectric constant than the insulator 324 . For example, the dielectric constant of insulator 326 is preferably less than 4, more preferably less than 3. Also, for example, the dielectric constant of the insulator 326 is preferably 0.7 times or less, more preferably 0.6 times or less, that of the insulator 324 . By using a material with a low dielectric constant as the interlayer film, the parasitic capacitance generated between wirings can be reduced.

In addition, the insulator 320, the insulator 322, the insulator 324, and the insulator 326 are embedded with conductors 328, 330, and the like connected to the capacitor 600 or the transistor 500, respectively. Note that the conductors 328 and 330 function as plugs or wirings. In addition, conductors that function as plugs or wiring may have a plurality of structures collectively given the same reference numerals. Further, in this specification and the like, the wiring and the plug connected to the wiring may be integrated. That is, part of the conductor may function as wiring, and part of the conductor may function as a plug.

As a material for each plug and wiring (conductor 328, conductor 330, etc.), a conductive material such as a metal material, an alloy material, a metal nitride material, or a metal oxide material is used as a single layer or a laminated layer. be able to. It is preferable to use a high-melting-point material such as tungsten or molybdenum that has both heat resistance and conductivity, and it is preferable to use tungsten. Alternatively, it is preferably made of a low resistance conductive material such as aluminum or copper. Wiring resistance can be reduced by using a low-resistance conductive material.

A wiring layer may be provided over the insulator 326 and the conductor 330 . For example, in FIG. 7, an insulator 350, an insulator 352, and an insulator 354 are stacked in this order. A conductor 356 is formed over the insulators 350 , 352 , and 354 . The conductor 356 functions as a plug or wiring connected to the transistor 300 . Note that the conductor 356 can be provided using a material similar to that of the conductors 328 and 330 .

Note that for the insulator 350 , for example, an insulator having a barrier property against hydrogen is preferably used, like the insulator 324 . Further, the conductor 356 preferably contains a conductor having a barrier property against hydrogen. In particular, a conductor having a barrier property against hydrogen is formed in the opening of the insulator 350 having a barrier property against hydrogen. With this structure, the transistor 300 and the transistor 500 can be separated by a barrier layer, and diffusion of hydrogen from the transistor 300 to the transistor 500 can be suppressed.

Note that tantalum nitride or the like may be used as the conductor having a barrier property against hydrogen, for example. Further, by stacking tantalum nitride and tungsten having high conductivity, diffusion of hydrogen from the transistor 300 can be suppressed while the conductivity of the wiring is maintained. In this case, it is preferable that the tantalum nitride layer having a barrier property against hydrogen be in contact with the insulator 350 having a barrier property against hydrogen.

A wiring layer may be provided over the insulator 354 and the conductor 356 . For example, in FIG. 7, an insulator 360, an insulator 362, and an insulator 364 are stacked in this order. A conductor 366 is formed over the insulators 360 , 362 , and 364 . The conductor 366 functions as a plug or wiring. Note that the conductor 366 can be provided using a material similar to that of the conductors 328 and 330 .

Note that for the insulator 360, for example, an insulator having a barrier property against hydrogen is preferably used, like the insulator 324. Further, the conductor 366 preferably contains a conductor having a barrier property against hydrogen. In particular, a conductor having a barrier property against hydrogen is formed in the opening of the insulator 360 having a barrier property against hydrogen. With this structure, the transistor 300 and the transistor 500 can be separated by a barrier layer, and diffusion of hydrogen from the transistor 300 to the transistor 500 can be suppressed.

A wiring layer may be provided over the insulator 364 and the conductor 366 . For example, in FIG. 7, an insulator 370, an insulator 372, and an insulator 374 are stacked in this order. A conductor 376 is formed over the insulators 370 , 372 , and 374 . The conductor 376 functions as a plug or wiring. Note that the conductor 376 can be provided using a material similar to that of the conductors 328 and 330 .

Note that for the insulator 370, for example, an insulator having a barrier property against hydrogen is preferably used like the insulator 324. Further, the conductor 376 preferably contains a conductor having a barrier property against hydrogen. In particular, a conductor having a barrier property against hydrogen is formed in the opening of the insulator 370 having a barrier property against hydrogen. With this structure, the transistor 300 and the transistor 500 can be separated by a barrier layer, and diffusion of hydrogen from the transistor 300 to the transistor 500 can be suppressed.

A wiring layer may be provided over the insulator 374 and the conductor 376 . For example, in FIG. 7, an insulator 380, an insulator 382, and an insulator 384 are stacked in order. A conductor 386 is formed over the insulators 380 , 382 , and 384 . The conductor 386 functions as a plug or wiring. Note that the conductor 386 can be provided using a material similar to that of the conductors 328 and 330 .

Note that for the insulator 380, for example, an insulator having a barrier property against hydrogen is preferably used like the insulator 324. Further, the conductor 386 preferably contains a conductor having a barrier property against hydrogen. In particular, a conductor having a barrier property against hydrogen is formed in the opening of the insulator 380 having a barrier property against hydrogen. With this structure, the transistor 300 and the transistor 500 can be separated by a barrier layer, and diffusion of hydrogen from the transistor 300 to the transistor 500 can be suppressed.

The wiring layer including the conductor 356, the wiring layer including the conductor 366, the wiring layer including the conductor 376, and the wiring layer including the conductor 386 are described above. It is not limited to this. The number of wiring layers similar to the wiring layer including the conductor 356 may be three or less, or the number of wiring layers similar to the wiring layer including the conductor 356 may be five or more.

An insulator 510 , an insulator 512 , an insulator 514 , and an insulator 516 are stacked in this order over the insulator 384 . Any of the insulator 510, the insulator 512, the insulator 514, and the insulator 516 is preferably a substance having barrier properties against oxygen and hydrogen.

For the insulators 510 and 514, for example, a film having barrier properties such that hydrogen or impurities do not diffuse from the substrate 311 or a region where the transistor 300 is provided to a region where the transistor 500 is provided is used. is preferred. Therefore, a material similar to that of the insulator 324 can be used.

As an example of a film having a barrier property against hydrogen, silicon nitride formed by a CVD method can be used. Here, diffusion of hydrogen into a semiconductor element including an oxide semiconductor, such as the transistor 500, might degrade the characteristics of the semiconductor element. Therefore, it is preferable to use a film that suppresses diffusion of hydrogen between the transistor 500 and the transistor 300 . Specifically, the film that suppresses diffusion of hydrogen is a film from which the amount of desorption of hydrogen is small.

As a film having a barrier property against hydrogen, for example, the insulators 510 and 514 are preferably formed using a metal oxide such as aluminum oxide, hafnium oxide, or tantalum oxide.

In particular, aluminum oxide has a high shielding effect of preventing the penetration of both oxygen and impurities such as hydrogen and moisture, which cause variations in the electrical characteristics of the transistor. Therefore, aluminum oxide can prevent impurities such as hydrogen and moisture from entering the transistor 500 during and after the manufacturing process of the transistor. In addition, release of oxygen from the oxide forming the transistor 500 can be suppressed. Therefore, it is suitable for use as a protective film for the transistor 500 .

Further, for example, the insulators 512 and 516 can be formed using a material similar to that of the insulator 320 . In addition, by using a material with a relatively low dielectric constant for these insulators, parasitic capacitance generated between wirings can be reduced. For example, the insulators 512 and 516 can be formed using a silicon oxide film, a silicon oxynitride film, or the like.

In addition, the insulator 510 , the insulator 512 , the insulator 514 , and the insulator 516 are embedded with a conductor 518 , a conductor forming the transistor 500 (eg, the conductor 503 ), and the like. Note that the conductor 518 functions as a plug or wiring that is connected to the capacitor 600 or the transistor 300 . The conductor 518 can be provided using a material similar to that of the conductors 328 and 330 .

In particular, a conductor 518 in a region in contact with the insulator 510 and the insulator 514 is preferably a conductor having barrier properties against oxygen, hydrogen, and water. With this structure, the transistor 300 and the transistor 500 can be separated by a layer having barrier properties against oxygen, hydrogen, and water, and diffusion of hydrogen from the transistor 300 to the transistor 500 can be suppressed.

A transistor 500 is provided above the insulator 516 .

As illustrated in FIGS. 9A and 9B, the transistor 500 is provided with a conductor 503 embedded in insulators 514 and 516 and over the insulators 516 and 503 . Insulator 520, insulator 522 over insulator 520, insulator 524 over insulator 522, oxide 530a over insulator 524, and oxide 530a an oxide 530b overlying a conductor 542a and a conductor 542b spaced apart from each other over the oxide 530b; An insulator 580 with an opening overlapping between them, an oxide 530c arranged on the bottom and side surfaces of the opening, an insulator 550 arranged on the formation surface of the oxide 530c, and an insulator 550 are formed. and a conductor 560 disposed on the surface.

An insulator 544 is preferably provided between the oxide 530a, the oxide 530b, the conductors 542a and 542b, and the insulator 580 as shown in FIGS. . 9A and 9B, the conductor 560 includes a conductor 560a provided inside the insulator 550 and a conductor 560b embedded inside the conductor 560a. and preferably. Further, an insulator 574 is preferably provided over the insulator 580, the conductor 560, and the insulator 550 as shown in FIGS.

Note that the oxide 530a, the oxide 530b, and the oxide 530c are collectively referred to as the oxide 530 in some cases below.

Note that although the transistor 500 has a structure in which three layers of the oxide 530a, the oxide 530b, and the oxide 530c are stacked in a region where a channel is formed and in the vicinity thereof, the present invention is limited to this. not a thing For example, a single layer of the oxide 530b, a two-layer structure of the oxides 530b and 530a, a two-layer structure of the oxides 530b and 530c, or a stacked structure of four or more layers may be employed. Although the conductor 560 has a two-layer structure in the transistor 500, 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. Further, the transistor 500 illustrated in FIGS. 7 and 9A is an example, and the structure is not limited, and an appropriate transistor may be used depending on the circuit structure and the driving method.

Here, the conductor 560 functions as a gate electrode of the transistor, and the conductors 542a and 542b function as source and drain electrodes, respectively. As described above, the conductor 560 is formed to be embedded in the opening of the insulator 580 and the region sandwiched between the conductors 542a and 542b. The placement of conductor 560 , conductor 542 a and conductor 542 b is selected in a self-aligned manner with respect to the opening in insulator 580 . That is, in the transistor 500, the gate electrode can be arranged between the source electrode and the drain electrode in a self-aligned manner. Therefore, the conductor 560 can be formed without providing an alignment margin, so that the area occupied by the transistor 500 can be reduced. As a result, miniaturization and high integration of the semiconductor device can be achieved.

Furthermore, since conductor 560 is formed in a region between conductors 542a and 542b in a self-aligned manner, conductor 560 does not have a region that overlaps conductors 542a or 542b. Accordingly, parasitic capacitance formed between the conductor 560 and the conductors 542a and 542b can be reduced. Therefore, the switching speed of the transistor 500 can be improved and high frequency characteristics can be obtained.

Conductor 560 may function as a first gate (also called top gate) electrode. In some cases, the conductor 503 functions as a second gate (also referred to as a bottom gate) electrode. In that case, the threshold voltage of the transistor 500 can be controlled by changing the potential applied to the conductor 503 independently of the potential applied to the conductor 560 . In particular, by applying a negative potential to the conductor 503, the threshold voltage of the transistor 500 can be made higher than 0 V and the off current can be reduced. Therefore, when a negative potential is applied to the conductor 503, the drain current when the potential applied to the conductor 560 is 0 V can be made smaller than when no potential is applied.

The conductor 503 is arranged so as to overlap with the oxide 530 and the conductor 560 . Accordingly, when a potential is applied to the conductor 560 and the conductor 503, the electric field generated from the conductor 560 and the electric field generated from the conductor 503 are connected to each other, so that the channel formation region formed in the oxide 530 is covered. can be done. In this specification and the like, a transistor structure in which a channel formation region is electrically surrounded by electric fields of a first gate electrode and a second gate electrode is referred to as a surrounded channel (S-channel) structure.

Further, in this specification and the like, the surrounded channel (S-channel) structure means that the side surfaces and the periphery of the oxide 530 in contact with the conductors 542a and 542b functioning as source and drain electrodes are the same as the channel formation region. It has the characteristic of being a type. In addition, since the side surface and the periphery of the oxide 530 that are in contact with the conductors 542a and 542b are in contact with the insulator 544, they can be i-type like the channel formation region. In this specification and the like, type I can be treated as the same as high-purity intrinsic, which will be described later. Also, the S-channel structure disclosed in this specification and the like is different from the Fin type structure and the planar type structure. By adopting the S-channel structure, it is possible to increase resistance to the short channel effect, in other words, to make the transistor less susceptible to the short channel effect.

The conductor 503 has the same structure as the conductor 518. A conductor 503a is formed in contact with the inner walls of the openings of the insulators 514 and 516, and a conductor 503b is formed inside. Note that although the structure in which the conductors 503a and 503b are stacked is shown in the transistor 500, the present invention is not limited to this. For example, the conductor 503 may be provided as a single layer or a laminated structure of three or more layers.

Here, for the conductor 503a, it is preferable to use a conductive material that has a function of suppressing diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, and copper atoms (the impurities are less likely to permeate). Alternatively, it is preferable to use a conductive material that has a function of suppressing diffusion of oxygen (eg, at least one of oxygen atoms, oxygen molecules, etc.) (the above oxygen is difficult to permeate). In this specification, the function of suppressing the diffusion of impurities or oxygen means the function of suppressing the diffusion of one or all of the impurities or oxygen.

For example, since the conductor 503a has a function of suppressing the diffusion of oxygen, it is possible to suppress a decrease in conductivity due to oxidation of the conductor 503b.

In the case where the conductor 503 also functions as a wiring, the conductor 503b is preferably made of a highly conductive material containing tungsten, copper, or aluminum as its main component. In that case, the conductor 505 is not necessarily provided. Note that although the conductor 503b is illustrated as a single layer, it may have a layered structure, for example, a layered layer of titanium, titanium nitride, and any of the above conductive materials.

The insulator 520, the insulator 522, the insulator 524, and the insulator 550 function as a second gate insulating film.

Here, the insulator 524 in contact with the oxide 530 preferably contains more oxygen than the stoichiometric composition. In other words, the insulator 524 preferably has an excess oxygen region. By providing such an insulator containing excess oxygen in contact with the oxide 530, oxygen vacancies in the oxide 530 can be reduced and the reliability of the transistor 500 can be improved.

Specifically, an oxide material from which part of oxygen is released by heating is preferably used as the insulator having the excess oxygen region. The oxide that desorbs oxygen by heating means that the desorption amount of oxygen in terms of oxygen atoms is 1.0×10 ¹⁸ atoms/cm ³ or more, preferably 1, in TDS (Thermal Desorption Spectroscopy) analysis. 0×10 ¹⁹ atoms/cm ³ or more, more preferably 2.0×10 ¹⁹ atoms/cm ³ or more, or 3.0×10 ²⁰ atoms/cm ³ or more. The surface temperature of the film during the TDS analysis is preferably in the range of 100° C. or higher and 700° C. or lower, or 100° C. or higher and 400° C. or lower.

Further, one or more of heat treatment, microwave treatment, and RF treatment may be performed while the insulator having the excess oxygen region and the oxide 530 are in contact with each other. By performing the treatment, water or hydrogen in the oxide 530 can be removed. For example, in the oxide 530, a reaction that breaks the bond of VoH occurs, in other words, a reaction of “V _OH →V 2 _O +H” occurs, and dehydrogenation can be performed. Part of the hydrogen generated at this time is combined with oxygen to form H ₂ O and removed from the oxide 530 or an insulator near the oxide 530 in some cases. In addition, part of hydrogen may be diffused or captured (also referred to as gettering) in the conductor 542 .

For the above microwave treatment, for example, it is preferable to use an apparatus having a power supply for generating high-density plasma or an apparatus having a power supply for applying RF to the substrate side. For example, by using a gas containing oxygen and using high-density plasma, high-density oxygen radicals can be generated. By applying RF to the substrate side, the oxygen radicals generated by the high-density plasma can be generated. , can be efficiently introduced into the oxide 530 or an insulator near the oxide 530 . Further, the microwave treatment may be performed at a pressure of 133 Pa or higher, preferably 200 Pa or higher, and more preferably 400 Pa or higher. In addition, for example, oxygen and argon are used as gases to be introduced into the apparatus for microwave treatment, and the oxygen flow rate ratio (O ₂ /(O ₂ +Ar)) is 50% or less, preferably 10% or more and 30%. % or less.

Further, heat treatment is preferably performed with the surface of the oxide 530 exposed during the manufacturing process of the transistor 500 . The heat treatment may be performed at, for example, 100° C. to 450° C., more preferably 350° C. to 400° C. Note that the heat treatment is performed in a nitrogen gas atmosphere, an inert gas atmosphere, or an atmosphere containing 10 ppm or more, 1% or more, or 10% or more of an oxidizing gas. For example, heat treatment is preferably performed in an oxygen atmosphere. Accordingly, oxygen can be supplied to the oxide 530 to reduce oxygen vacancies (V ₀ ). Moreover, you may perform heat processing in a pressure-reduced state. Alternatively, the heat treatment may be performed in an atmosphere containing 10 ppm or more, 1% or more, or 10% or more of an oxidizing gas in order to compensate for desorbed oxygen after the heat treatment is performed in a nitrogen gas or inert gas atmosphere. good. Alternatively, after heat treatment in an atmosphere containing 10 ppm or more, 1% or more, or 10% or more of an oxidizing gas, heat treatment may be continuously performed in a nitrogen gas or inert gas atmosphere.

Note that by performing oxygenation treatment on the oxide 530, oxygen vacancies in the oxide 530 can be repaired by the supplied oxygen, in other words, the reaction “V 2 _O +O→null” can be promoted. . Furthermore, the supplied oxygen reacts with the hydrogen remaining in the oxide 530, so that the hydrogen can be removed as H ₂ O (dehydrated). Accordingly, hydrogen remaining in the oxide 530 can be suppressed from being recombined with oxygen vacancies to form _VOH .

In addition, when the insulator 524 has an excess oxygen region, the insulator 522 preferably has a function of suppressing diffusion of oxygen (eg, oxygen atoms, oxygen molecules, etc.) (the above oxygen is difficult to permeate).

Since the insulator 522 has a function of suppressing diffusion of oxygen and impurities, oxygen contained in the oxide 530 does not diffuse toward the insulator 520, which is preferable. In addition, the conductor 503 can be prevented from reacting with oxygen contained in the insulator 524 and the oxide 530 .

The insulator 522 is, for example, aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium aluminate), tantalum oxide, zirconium oxide, lead zirconate titanate (PZT), strontium titanate ( _SrTiO3 ), or It is preferable to use an insulator containing a so-called high-k material such as (Ba,Sr)TiO ₃ (BST) in a single layer or a laminated layer. As transistors are miniaturized and highly integrated, thinning of gate insulating films may cause problems such as leakage current. By using a high-k material for the insulator that functions as the gate insulating film, it is possible to reduce the gate potential during transistor operation while maintaining the physical film thickness.

In particular, an insulator containing an oxide of one or both of aluminum and hafnium, which is an insulating material having a function of suppressing diffusion of impurities and oxygen (through which oxygen is difficult to permeate), is preferably used. As the insulator containing oxides of one or both of aluminum and hafnium, aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium aluminate), or the like is preferably used. When the insulator 522 is formed using such a material, the insulator 522 suppresses release of oxygen from the oxide 530 and entry of impurities such as hydrogen from the periphery of the transistor 500 into the oxide 530. act as a layer.

Alternatively, aluminum oxide, bismuth oxide, germanium oxide, niobium oxide, silicon oxide, titanium oxide, tungsten oxide, yttrium oxide, or zirconium oxide may be added to these insulators. Alternatively, these insulators may be nitrided. Silicon oxide, silicon oxynitride, or silicon nitride may be stacked over the above insulator.

Insulator 520 is also preferably thermally stable. For example, silicon oxide and silicon oxynitride are preferred because they are thermally stable. Further, by combining an insulator made of a high-k material with silicon oxide or silicon oxynitride, the insulators 520 and 526 having a stacked structure which are thermally stable and have a high relative dielectric constant can be obtained.

Note that in the transistor 500 in FIGS. 10A and 10B, the insulator 520, the insulator 522, and the insulator 524 are illustrated as the second gate insulating film having a stacked-layer structure of three layers. The second gate insulating film may have a single layer, two layers, or a laminated structure of four or more layers. In that case, it is not limited to a laminated structure made of the same material, and a laminated structure made of different materials may be used.

An oxide semiconductor is preferably used for the oxide 530 including a channel formation region in the transistor 500 . For example, as the oxide 530, In-M-Zn oxide (element M is aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium , hafnium, tantalum, tungsten, magnesium, or the like) may be used. Particularly, the In-M-Zn oxide that can be applied as the oxide 530 is preferably CAAC-OS (c-axis aligned crystalline oxide semiconductor) or CAC-OS (Cloud-Aligned Composite Oxide Semiconductor). CAAC-OS refers to an oxide having a CAAC structure, and the CAAC structure is a crystal structure in which a plurality of IGZO nanocrystals have a c-axis orientation and are connected without being oriented in the ab plane. is. A CAC-OS is, for example, one structure of a material in which elements constituting an oxide semiconductor are unevenly distributed with a size of 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 2 nm or less, or in the vicinity thereof. Note that hereinafter, in the oxide semiconductor, one or more metal elements are unevenly distributed, and the region having the metal element has a size of 0.5 nm or more and 10 nm or less, preferably 1 nm or more and 2 nm or less, or a size in the vicinity thereof. The mixed state is also called a mosaic shape or a patch shape. Alternatively, as the oxide 530, an In--Ga oxide or an In--Zn oxide may be used.

An oxide semiconductor with low carrier concentration is preferably used for the transistor 500 . In the case of lowering the carrier concentration of the oxide semiconductor, the impurity concentration in the oxide semiconductor may be lowered to lower the defect level density. In this specification and the like, a low impurity concentration and a low defect level density are referred to as high-purity intrinsic or substantially high-purity intrinsic. Note that impurities in an oxide semiconductor include, for example, hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, silicon, and the like.

In particular, hydrogen contained in an oxide semiconductor reacts with oxygen that bonds to a metal atom to become water; thus, an oxygen vacancy (V _{2 O} ) may be formed in the oxide semiconductor. Further, when hydrogen enters oxygen vacancies in the oxide semiconductor, the oxygen vacancies and hydrogen may combine to form _VOH . _VOH may function as a donor and generate an electron, which is a carrier. In addition, part of hydrogen may bond with oxygen that bonds with a metal atom to generate an electron that is a carrier. Therefore, a transistor including an oxide semiconductor containing a large amount of hydrogen is likely to have normally-on characteristics. In addition, hydrogen in an oxide semiconductor easily moves due to stress such as heat and an electric field; therefore, when a large amount of hydrogen is contained in the oxide semiconductor, the reliability of the transistor might be deteriorated. In one aspect of the present invention, it is preferred to reduce V _OH in oxide 530 as much as possible to be highly pure intrinsic or substantially highly pure intrinsic. In order to obtain an oxide semiconductor in which V _OH is sufficiently reduced in this way, impurities such as moisture and hydrogen in the oxide semiconductor are removed (sometimes referred to as dehydration or dehydrogenation treatment). In addition, it is important to supply oxygen to the oxide semiconductor to fill oxygen vacancies (sometimes referred to as oxygenation treatment). By using an oxide semiconductor in which impurities such as V _OH are sufficiently reduced for a channel formation region of a transistor, stable electrical characteristics can be imparted.

A defect in which hydrogen enters an oxygen vacancy can function as a donor of an oxide semiconductor. However, it is difficult to quantitatively evaluate the defects. Therefore, in some cases, the oxide semiconductor is evaluated based on the carrier concentration instead of the donor concentration. Therefore, in this specification and the like, instead of the donor concentration, the carrier concentration assuming a state in which no electric field is applied is used as a parameter of the oxide semiconductor in some cases. In other words, the “carrier concentration” described in this specification and the like may be rephrased as “donor concentration”.

Therefore, when an oxide semiconductor is used for the oxide 530, hydrogen in the oxide semiconductor is preferably reduced as much as possible. Specifically, in the oxide semiconductor, the hydrogen concentration obtained by secondary ion mass spectrometry (SIMS) is less than 1×10 ²⁰ atoms/cm ³ , preferably 1×10 ¹⁹ atoms/cm. It is less than ³ , more preferably less than 5×10 ¹⁸ atoms/cm ³ , still more preferably less than 1×10 ¹⁸ atoms/cm ³ . By using an oxide semiconductor in which impurities such as hydrogen are sufficiently reduced for a channel formation region of a transistor, stable electrical characteristics can be imparted.

In the case where an oxide semiconductor is used for the oxide 530, the carrier concentration of the oxide semiconductor with the channel formation region is preferably 1×10 ¹⁸ cm ⁻³ or less and less than 1×10 ¹⁷ cm ⁻³ . is more preferably less than 1×10 ¹⁶ cm ⁻³ , still more preferably less than 1×10 ¹³ cm ⁻³ , even more preferably less than 1×10 ¹² cm ⁻³ . Note that the lower limit of the carrier concentration of the oxide semiconductor in the channel formation region is not particularly limited, but can be set to 1×10 ⁻⁹ cm ⁻³ , for example.

In the case where an oxide semiconductor is used for the oxide 530, the conductors 542 (the conductors 542a and 542b) are in contact with the oxide 530, whereby oxygen in the oxide 530 diffuses into the conductor 542. Conductor 542 may oxidize. Oxidation of the conductor 542 is highly likely to reduce the conductivity of the conductor 542 . Note that diffusion of oxygen in the oxide 530 to the conductor 542 can be rephrased as that the conductor 542 absorbs oxygen in the oxide 530 .

Further, oxygen in the oxide 530 diffuses into the conductor 542 (the conductor 542a and the conductor 542b), so that the conductor 542a and the oxide 530b and the conductor 542b and the oxide 530b are diffused. Different layers may form between them. Since the different layer contains more oxygen than the conductor 542, the different layer is presumed to have insulating properties. At this time, the three-layer structure of the conductor 542, the different layer, and the oxide 530b can be regarded as a three-layer structure composed of metal-insulator-semiconductor, and is called a metal-insulator-semiconductor (MIS) structure. Alternatively, it may be called a diode junction structure mainly composed of the MIS structure.

Note that the different layer is not limited to being formed between the conductor 542 and the oxide 530b. It may form between body 542 and oxide 530b and between conductor 542 and oxide 530c.

Further, an oxide semiconductor that functions as a channel formation region in the oxide 530 preferably has a bandgap of 2 eV or more, preferably 2.5 eV or more. By using an oxide semiconductor with a large bandgap in this manner, the off-state current of the transistor can be reduced.

Since the oxide 530 includes the oxide 530a under the oxide 530b, diffusion of impurities from a structure formed below the oxide 530a to the oxide 530b can be suppressed. In addition, by providing the oxide 530c over the oxide 530b, diffusion of impurities from a structure formed above the oxide 530c to the oxide 530b can be suppressed.

Note that the oxide 530 preferably has a layered structure with oxides having different atomic ratios of metal atoms. Specifically, in the oxide semiconductor used for the oxide 530a, the atomic ratio of the element M among the constituent elements is higher than the atomic ratio of the element M among the constituent elements in the oxide semiconductor used for the oxide 530b. is preferred. Further, the atomic ratio of the element M to In in the oxide semiconductor used for the oxide 530a is preferably higher than the atomic ratio of the element M to In in the oxide semiconductor used for the oxide 530b. Further, the atomic ratio of In to the element M in the oxide semiconductor used for the oxide 530b is preferably higher than the atomic ratio of In to the element M in the oxide semiconductor used for the oxide 530a. For the oxide 530c, an oxide semiconductor that can be used for the oxide 530a or the oxide 530b can be used.

In addition, it is preferable that the energies of the conduction band bottoms of the oxides 530a and 530c be higher than the energies of the conduction band bottoms of the oxide 530b. In other words, the electron affinities of the oxides 530a and 530c are preferably smaller than that of the oxide 530b.

Here, the energy level at the bottom of the conduction band changes smoothly at the junction of the oxide 530a, the oxide 530b, and the oxide 530c. In other words, it can be said that the energy level of the bottom of the conduction band at the junction of the oxide 530a, the oxide 530b, and the oxide 530c continuously changes or continuously joins. In order to achieve this, the defect level density of the mixed layers formed at the interface between the oxides 530a and 530b and the interface between the oxides 530b and 530c should be lowered.

Specifically, the oxide 530a and the oxide 530b, and the oxide 530b and the oxide 530c have a common element (main component) other than oxygen, thereby forming a mixed layer with a low defect level density. be able to. For example, when the oxide 530b is an In--Ga--Zn oxide, the oxides 530a and 530c may be In--Ga--Zn oxide, Ga--Zn oxide, gallium oxide, or the like.

At this time, the main path of carriers is the oxide 530b. When the oxides 530a and 530c have the above structure, defect level densities at the interfaces between the oxides 530a and 530b and between the oxides 530b and 530c can be reduced. Therefore, the influence of interface scattering on carrier conduction is reduced, and the transistor 500 can obtain a high on-state current.

Conductors 542a and 542b functioning as source and drain electrodes are provided over the oxide 530b. Conductors 542a and 542b include aluminum, chromium, copper, silver, gold, platinum, tantalum, nickel, titanium, molybdenum, tungsten, hafnium, vanadium, niobium, manganese, magnesium, zirconium, beryllium, indium, and ruthenium. , iridium, strontium, and lanthanum, an alloy containing the above-described metal elements as a component, or an alloy in which the above-described metal elements are combined. For example, tantalum nitride, titanium nitride, tungsten, nitride containing titanium and aluminum, nitride containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxide containing strontium and ruthenium, oxide containing lanthanum and nickel, and the like are used. is preferred. Also, tantalum nitride, titanium nitride, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, and oxides containing lanthanum and nickel are difficult to oxidize. It is preferable because it is a conductive material or a material that maintains conductivity even after absorbing oxygen. Furthermore, a metal nitride film such as tantalum nitride is preferable because it has a barrier property against hydrogen or oxygen.

In addition, although the conductor 542a and the conductor 542b have a single-layer structure in FIG. 9, they may have a stacked structure of two or more layers. For example, a tantalum nitride film and a tungsten film are preferably stacked. Alternatively, a titanium film and an aluminum film may be stacked. A two-layer structure in which an aluminum film is stacked over a tungsten film, a two-layer structure in which a copper film is stacked over a copper-magnesium-aluminum alloy film, a two-layer structure in which a copper film is stacked over a titanium film, a two-layer structure in which a copper film is stacked over a titanium film, A two-layer structure in which copper films are stacked may be used.

Further, a three-layer structure in which a titanium film or a titanium nitride film is laminated, an aluminum film or a copper film is laminated on the titanium film or the titanium nitride film, and a titanium film or a titanium nitride film is formed thereon, a molybdenum film or a There is a three-layer structure including a molybdenum nitride film, an aluminum film or a copper film laminated on the molybdenum film or the molybdenum nitride film, and a molybdenum film or a molybdenum nitride film formed thereon. Note that a transparent conductive material containing indium oxide, tin oxide, or zinc oxide may be used.

9A, regions 543a and 543b are formed as low-resistance regions at the interface between the oxide 530 and the conductor 542a (conductor 542b) and in the vicinity thereof. There is At this time, the region 543a functions as one of the source region and the drain region, and the region 543b functions as the other of the source region and the drain region. A channel formation region is formed in a region sandwiched between the regions 543a and 543b.

By providing the conductor 542a (the conductor 542b) so as to be in contact with the oxide 530, the oxygen concentration of the region 543a (the region 543b) may be reduced. In some cases, a metal compound layer containing the metal contained in the conductor 542a (conductor 542b) and the component of the oxide 530 is formed in the region 543a (region 543b). In such a case, the carrier concentration of the region 543a (region 543b) increases and the region 543a (region 543b) becomes a low resistance region.

The insulator 544 is provided so as to cover the conductors 542a and 542b and suppress oxidation of the conductors 542a and 542b. At this time, the insulator 544 may be provided so as to cover the side surface of the oxide 530 and be in contact with the insulator 524 .

The insulator 544 is a metal oxide containing one or more selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, neodymium, lanthanum, magnesium, and the like. can be used. Alternatively, silicon nitride oxide, silicon nitride, or the like can be used as the insulator 544 .

In particular, as the insulator 544, an insulator containing one or both oxides of aluminum and hafnium, such as aluminum oxide, hafnium oxide, or an oxide containing aluminum and hafnium (hafnium aluminate), is preferably used. . In particular, hafnium aluminate has higher heat resistance than hafnium oxide film. Therefore, it is preferable because it is less likely to be crystallized in heat treatment in a later step. Note that the insulator 544 is not essential when the conductors 542a and 542b are made of an oxidation-resistant material or when the conductivity does not significantly decrease even when oxygen is absorbed. It may be appropriately designed depending on the required transistor characteristics.

The insulator 544 can suppress diffusion of impurities such as water and hydrogen contained in the insulator 580 through the oxide 530c and the insulator 550 into the oxide 530b. In addition, oxidation of the conductor 560 due to excess oxygen in the insulator 580 can be suppressed.

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

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

By providing an insulator from which oxygen is released by heating as the insulator 550 in contact with the top surface of the oxide 530c, oxygen is effectively introduced from the insulator 550 to the channel formation region of the oxide 530b through the oxide 530c. can be supplied. Further, similarly to the insulator 524, the concentration of impurities such as water or hydrogen in the insulator 550 is preferably reduced. The thickness of the insulator 550 is preferably 1 nm or more and 20 nm or less.

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

Note that the insulator 550 may have a stacked structure similarly to the second gate insulating film. As transistors are miniaturized and highly integrated, thinning of the gate insulating film may cause problems such as leakage current. By forming a laminated structure with a material that is relatively stable, it is possible to reduce the gate potential during transistor operation while maintaining the physical film thickness. Moreover, it is possible to obtain a laminated structure that is thermally stable and has a high dielectric constant.

Although the conductor 560 functioning as the first gate electrode has a two-layer structure in FIGS. 9A and 9B, it may have a single-layer structure or a stacked structure of three or more layers.

The conductor 560a has a function of suppressing diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules (such as N ₂ O, NO, NO ₂ ), and copper atoms. Materials are preferably used. Alternatively, a conductive material having a function of suppressing diffusion of oxygen (eg, at least one of oxygen atoms and oxygen molecules) is preferably used. Since the conductor 560a has a function of suppressing diffusion of oxygen, oxygen contained in the insulator 550 can suppress oxidation of the conductor 560b and a decrease in conductivity. As the conductive material having a function of suppressing diffusion of oxygen, tantalum, tantalum nitride, ruthenium, ruthenium oxide, or the like is preferably used, for example. Further, an oxide semiconductor that can be used for the oxide 530 can be used as the conductor 560a. In that case, by forming the conductor 560b by a sputtering method, the electric resistance value of the conductor 560a can be lowered to make the conductor 560a a conductor. This can be called an OC (Oxide Conductor) electrode.

A conductive material containing tungsten, copper, or aluminum as its main component is preferably used for the conductor 560b. In addition, since the conductor 560b also functions as a wiring, a conductor with high conductivity is preferably used. For example, a conductive material whose main component is tungsten, copper, or aluminum can be used. Further, the conductor 560b may have a layered structure, for example, a layered structure of titanium, titanium nitride, and the above conductive material.

The insulator 580 is provided over the conductors 542a and 542b with the insulator 544 interposed therebetween. Insulator 580 preferably has excess oxygen regions. For example, the insulator 580 may be silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide to which fluorine is added, silicon oxide to which carbon is added, silicon oxide to which carbon and nitrogen are added, or oxide with vacancies. It preferably contains silicon, resin, or the like. In particular, silicon oxide and silicon oxynitride are preferable because they are thermally stable. In particular, silicon oxide and silicon oxide having vacancies are preferable because an excess oxygen region can be easily formed in a later step.

Insulator 580 preferably has excess oxygen regions. By providing the insulator 580 from which oxygen is released by heating in contact with the oxide 530c, oxygen in the insulator 580 can be efficiently supplied to the oxide 530 through the oxide 530c. Note that the concentration of impurities such as water or hydrogen in the insulator 580 is preferably low.

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

When miniaturizing a semiconductor device, it is required to shorten the gate length, but it is necessary to prevent the conductivity of the conductor 560 from being lowered. Therefore, when the film thickness of the conductor 560 is increased, the conductor 560 can have a shape with a high aspect ratio. In this embodiment mode, since the conductor 560 is embedded in the opening of the insulator 580, the conductor 560 can be formed without collapsing during the process even if the conductor 560 has a high aspect ratio. can be done.

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

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

In particular, aluminum oxide has a high barrier property and can suppress diffusion of hydrogen and nitrogen even in a thin film having a thickness of 0.5 nm or more and 3.0 nm or less. Therefore, the aluminum oxide film formed by the sputtering method can function not only as an oxygen supply source but also as a barrier film against impurities such as hydrogen.

Note that after the transistor 500 is formed, an opening may be formed so as to surround the transistor 500, and an insulator having a high barrier property against hydrogen or water may be formed so as to cover the opening. By wrapping the transistor 500 with the above insulator with a high barrier property, entry of moisture and hydrogen from the outside can be prevented. Alternatively, the plurality of transistors 500 may be wrapped together with an insulator having a high barrier property against hydrogen or water. Note that in the case where the opening is formed so as to surround the transistor 500, for example, the opening is formed to reach the insulator 514 or the insulator 522, and the above insulator with a high barrier property is provided so as to be in contact with the insulator 514 or the insulator 522. It is preferable to form the transistor 500 because it can also be part of the manufacturing process of the transistor 500 . Note that as the insulator with high barrier properties against hydrogen or water, a material similar to that of the insulator 522 may be used, for example.

An insulator 581 functioning as an interlayer film is preferably provided over the insulator 574 . The insulator 581 preferably has a reduced concentration of impurities such as water or hydrogen in the film, similarly to the insulator 524 and the like.

In addition, conductors 540 a and 540 b are provided in openings formed in the insulators 581 , 574 , 580 , and 544 . The conductor 540a and the conductor 540b are provided to face each other with the conductor 560 interposed therebetween. The conductors 540a and 540b have the same structure as the conductors 546 and 548, which are described later.

An insulator 582 is provided over the insulator 581 . It is preferable that the insulator 582 use a substance that has a barrier property against oxygen and hydrogen. Therefore, a material similar to that of the insulator 514 can be used for the insulator 582 . For example, the insulator 582 is preferably formed using a metal oxide such as aluminum oxide, hafnium oxide, or tantalum oxide.

In particular, aluminum oxide has a high shielding effect of preventing the penetration of both oxygen and impurities such as hydrogen and moisture, which cause variations in the electrical characteristics of the transistor. Therefore, aluminum oxide can prevent impurities such as hydrogen and moisture from entering the transistor 500 during and after the manufacturing process of the transistor. In addition, release of oxygen from the oxide forming the transistor 500 can be suppressed. Therefore, it is suitable for use as a protective film for the transistor 500 .

An insulator 586 is provided over the insulator 582 . A material similar to that of the insulator 320 can be used for the insulator 586 . In addition, by using a material with a relatively low dielectric constant for these insulators, parasitic capacitance generated between wirings can be reduced. For example, a silicon oxide film, a silicon oxynitride film, or the like can be used as the insulator 586 .

In addition, the insulator 520, the insulator 522, the insulator 524, the insulator 544, the insulator 580, the insulator 574, the insulator 581, the insulator 582, and the insulator 586 include the conductor 546, the conductor 548, and the like. is embedded.

The conductors 546 and 548 function as plugs or wirings that connect to the capacitor 600 , the transistor 500 , or the transistor 300 . The conductors 546 and 548 can be formed using a material similar to that of the conductors 328 and 330 .

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

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

The conductors 612 and 610 are metal films containing elements selected from molybdenum, titanium, tantalum, tungsten, aluminum, copper, chromium, neodymium, and scandium, or metal nitride films containing any of the above elements. (tantalum nitride film, titanium nitride film, molybdenum nitride film, tungsten nitride film) or the like can be used. Alternatively, indium tin oxide, indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium zinc oxide, and silicon oxide are added. Conductive materials such as indium tin oxide can also be applied.

Although the conductors 612 and 610 have a single-layer structure in FIGS. 7A and 7B, they are not limited to this structure and may have a stacked structure of two or more layers. For example, between a conductor with barrier properties and a conductor with high conductivity, a conductor with barrier properties and a conductor with high adhesion to the conductor with high conductivity may be formed.

A conductor 620 is provided so as to overlap with the conductor 610 with an insulator 630 interposed therebetween. Note that a conductive material such as a metal material, an alloy material, or a metal oxide material can be used for the conductor 620 . It is preferable to use a high-melting-point material such as tungsten or molybdenum that has both heat resistance and conductivity, and it is particularly preferable to use tungsten. In addition, when forming simultaneously with another structure such as a conductor, a low-resistance metal material such as Cu (copper) or Al (aluminum) may be used.

An insulator 640 is provided over the conductor 620 and the insulator 630 . The insulator 640 can be provided using a material similar to that of the insulator 320 . In addition, the insulator 640 may function as a planarizing film that covers the uneven shape thereunder.

By using this structure, a semiconductor device including a transistor including an oxide semiconductor can be miniaturized or highly integrated.

(Embodiment 4)
In this embodiment, an example of a cylindrical secondary battery will be described with reference to FIGS. As shown in FIG. 10A, a cylindrical secondary battery 616 has a positive electrode cap (battery lid) 601 on its top surface and battery cans (armor cans) 602 on its side and bottom surfaces. The positive electrode cap and the battery can (outer can) 602 are insulated by a gasket (insulating packing) 610 . A protection circuit board 618 covered with a resin cover is electrically connected to the vicinity of the bottom surface of the battery can of the secondary battery 616 .

An electronic component 700 shown in FIG. 10C is an IC semiconductor device and has leads and a circuit portion. The circuit unit includes, for example, the remaining battery level measurement circuit described in the first embodiment. Electronic component 700 is mounted, for example, on a printed circuit board. Protection circuit board 618 is a printed circuit board on which one or more electronic components 700 are mounted.

FIG. 10B is a schematic cross-sectional view of a cylindrical secondary battery. A battery element in which a strip-shaped positive electrode 604 and a strip-shaped negative electrode 606 are wound with a separator 605 interposed therebetween is provided inside a hollow columnar battery can 602 . Although not shown, the battery element is wound around a center pin. Battery can 602 is closed at one end and open at the other end. The battery can 602 can be made of a metal such as nickel, aluminum, or titanium that is resistant to corrosion by the electrolyte, an alloy thereof, or an alloy of these metals with another metal (for example, stainless steel). . Also, in order to prevent corrosion due to the electrolyte, it is preferable to coat with nickel, aluminum, or the like. Inside the battery can 602 , the battery element in which the positive electrode, the negative electrode and the separator are wound is sandwiched between a pair of insulating plates 608 and 609 facing each other. A non-aqueous electrolyte (not shown) is filled inside the battery can 602 in which the battery element is provided. The same non-aqueous electrolyte as used in coin-type secondary batteries can be used.

Since the positive electrode and the negative electrode used in a cylindrical secondary battery are wound, it is preferable to form the active material on both sides of the current collector. A positive electrode terminal (positive collector lead) 603 is connected to the positive electrode 604 , and a negative electrode terminal (negative collector lead) 607 is connected to the negative electrode 606 . A metal material such as aluminum can be used for both the positive terminal 603 and the negative terminal 607 . The positive terminal 603 and the negative terminal 607 are resistance welded to the safety valve mechanism 617 and the bottom of the battery can 602, respectively. The safety valve mechanism 617 is electrically connected to the positive electrode cap 601 via a PTC element (Positive Temperature Coefficient) 611 . The safety valve mechanism 617 disconnects the electrical connection between the positive electrode cap 601 and the positive electrode 604 when the increase in internal pressure of the battery exceeds a predetermined threshold. The PTC element 611 is a thermal resistance element whose resistance increases when the temperature rises, and the increase in resistance limits the amount of current to prevent abnormal heat generation. Barium titanate (BaTiO ₃ ) semiconductor ceramics or the like can be used for the PTC element.

[Structural example of secondary battery]
Another structural example of the secondary battery is described with reference to FIGS.

11(A) and 11(B) are diagrams showing external views of the battery pack. The battery pack has a circuit board 900 and a secondary battery 913 . A secondary battery 913 has a terminal 951 and a terminal 952 and is covered with a label 910 . The battery pack may also have an antenna 914 . The secondary battery 913 can also be charged without contact using the antenna 914 .

The circuit board 900 is fixed with a seal 915 . Electronic component 700 is mounted on circuit board 900, and includes, for example, the remaining battery level measurement circuit described in the first embodiment. Terminal 911 is electrically connected to terminals 951 and 952 of secondary battery 913 through circuit board 900 . Also, the terminal 911 is electrically connected to the antenna 914 and the electronic component 700 through the circuit board 900 . Note that a plurality of terminals 911 may be provided and each of the plurality of terminals 911 may be used as a control signal input terminal, a power supply terminal, or the like.

The electronic component 700 detects an abnormality such as a micro-short. Furthermore, it may have a function as a protection circuit that protects the secondary battery 913 from overcharge, overdischarge, and overcurrent. Electronic component 700 may be provided on the back surface of circuit board 900 . Note that the antenna 914 is not limited to a coil shape, and may have a linear shape or a plate shape, for example. Further, antennas such as planar antennas, aperture antennas, traveling wave antennas, EH antennas, magnetic field antennas, and dielectric antennas may be used. Antenna 914 has a function of performing data communication with an external device, for example. As a communication method between the battery pack and the other device via the antenna 914, a response method such as NFC that can be used between the battery pack and the other device can be applied.

The battery pack has layer 916 between antenna 914 and secondary battery 913 . The layer 916 has a function of preventing the influence of the secondary battery 913 on the electromagnetic field, for example. A magnetic material, for example, can be used as the layer 916 .

Note that the structure of the battery pack is not limited to that shown in FIG.

For example, as shown in FIGS. 12A-1 and 12A-2, of the secondary battery 913 shown in FIGS. 918 may be provided. FIG. 12A-1 is an external view of the pair of surfaces viewed from one side, and FIG. 12A-2 is an external view of the pair of surfaces viewed from the other side. Note that the description of the battery pack shown in FIGS. 11A and 11B can be used as appropriate for the same parts as those of the battery pack shown in FIGS. 11A and 11B.

As shown in FIG. 12A-1, an antenna 914 is provided on one of a pair of surfaces of a secondary battery 913 with a layer 916 interposed therebetween, and as shown in FIG. An antenna 918 is provided with a layer 917 interposed on the other of the pair of surfaces. The layer 917 has a function of preventing the influence of the secondary battery 913 on the electromagnetic field, for example. A magnetic material, for example, can be used as the layer 917 .

With the above structure, two antennas can be provided in the battery pack, and the sizes of both the antennas 914 and 918 can be increased.

An antenna having a shape applicable to the antenna 914 can be applied to the antenna 918 . Further, the antenna 918 may be a planar conductor. This flat conductor can function as one of conductors for electric field coupling. In other words, the antenna 914 may function as one of the two conductors of the capacitor. As a result, electric power can be exchanged not only by electromagnetic fields and magnetic fields, but also by electric fields. A charge control circuit is provided between these antennas and the secondary battery, and a protection circuit electrically connected to the secondary battery may be provided.

Alternatively, as shown in FIG. 12B-1, the display device 920 may be provided in the battery packs shown in FIGS. 11A and 11B. The display device 920 is electrically connected to the terminals 911 . Note that the description of the battery pack shown in FIGS. 11A and 11B can be used as appropriate for the same parts as those of the battery pack shown in FIGS. 11A and 11B.

The display device 920 may display, for example, an image indicating whether or not the battery is being charged, an image indicating the remaining amount of the secondary battery, information warning of the occurrence of an abnormality, and the like. As the display device 920, electronic paper, a liquid crystal display device, an electroluminescence (also referred to as EL) display device, or the like can be used, for example. For example, by using electronic paper, power consumption of the display device 920 can be reduced.

Alternatively, as shown in FIG. 12B-2, a sensor 921 may be provided in the secondary battery 913 shown in FIGS. 11A and 11B. Sensor 921 is electrically connected to terminal 911 through terminal 922 and circuit board 900 . Note that the description of the secondary battery illustrated in FIGS. 11A and 11B can be used as appropriate for the same portions as those of the secondary battery illustrated in FIGS.

Sensors 921 include, for example, displacement, position, speed, acceleration, angular velocity, number of revolutions, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate , humidity, gradient, vibration, smell, or infrared rays. By providing the sensor 921 , for example, data (such as temperature) indicating the environment in which the secondary battery is placed can be detected and stored in the memory within the electronic component 700 . FIG. 12C is an example of a top view of the circuit board 900. FIG. The terminal 961 of the circuit board is connected with the terminal 951 and the terminal 962 is electrically connected with the terminal 952 . Terminal 922 of sensor 921 is electrically connected to terminal 963 of circuit board 900 . Inputs from these terminals are input to the electronic component 700, and abnormalities such as micro-shorts can be detected based on the information.

Further, a structural example of the secondary battery 913 is described with reference to FIGS.

A secondary battery 913 illustrated in FIG. 13A includes a wound body 950 provided with a terminal 951 and a terminal 952 inside a housing 930 . The wound body 950 is impregnated with the electrolytic solution inside the housing 930 . The terminal 952 is in contact with the housing 930, and the terminal 951 is not in contact with the housing 930 by using an insulating material or the like. Note that in FIG. 13A , the housing 930 is shown separately for convenience, but actually, the wound body 950 is covered with the housing 930 and the terminals 951 and 952 are connected to the housing 930 . extending outside. As the housing 930, a metal material (such as aluminum) or a resin material can be used.

Note that as shown in FIG. 13B, the housing 930 shown in FIG. 13A may be formed using a plurality of materials. For example, in a secondary battery 913 illustrated in FIG. 13B, a housing 930a and a housing 930b are attached to each other, and a wound body 950 is provided in a region surrounded by the housings 930a and 930b. .

An insulating material such as an organic resin can be used for the housing 930a. In particular, by using a material such as an organic resin for the surface on which the antenna is formed, shielding of the electric field by the secondary battery 913 can be suppressed. Note that an antenna such as the antenna 914 may be provided inside the housing 930a if the shielding of the electric field by the housing 930a is small. A metal material, for example, can be used as the housing 930b.

Furthermore, the structure of the wound body 950 is shown in FIG. A wound body 950 has a negative electrode 931 , a positive electrode 932 , and a separator 933 . The wound body 950 is a wound body in which the negative electrode 931 and the positive electrode 932 are laminated with the separator 933 interposed therebetween, and the laminated sheet is wound. Note that the negative electrode 931, the positive electrode 932, and the separator 933 may be stacked more than once.

The negative electrode 931 is connected to the terminal 911 shown in FIG. 11 through one of the terminals 951 and 952 . The positive electrode 932 is connected to the terminal 911 shown in FIG. 11 through the other of the terminals 951 and 952 .

Electronic component 700 is mounted on circuit board 900 electrically connected to terminals 952 and 911 shown in FIG. The state of charge of the secondary battery 913 can be accurately known.

(Embodiment 5)
In the above-described embodiment, an example in which one electronic component 700 is provided on a circuit board is shown, but there is no particular limitation, and an interposer is provided on a package substrate (printed circuit board), and a plurality of IC semiconductor devices are combined on the interposer. Any electronic component 730 may be used. Electronic component 700 or electronic component 730 has the battery remaining amount measuring circuit of Embodiment 1 described above, and can know the charging state of the secondary battery.

In this embodiment, an example of an electronic device including a protection circuit will be described with reference to FIGS.

The robot 7100 includes a secondary battery, an illumination sensor, a microphone, a camera, a speaker, a display, various sensors (infrared sensor, ultrasonic sensor, acceleration sensor, piezo sensor, optical sensor, gyro sensor, etc.), a moving mechanism, and the like. Since the battery remaining amount measuring circuit shown in Embodiment 1 connected to the secondary battery of the robot 7100 is included, the charged state of the secondary battery can be accurately known.

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

The camera has a function of capturing images around the robot 7100 . Robot 7100 also has a function of moving using a moving mechanism. The robot 7100 can capture an image of its surroundings using a camera, analyze the image, and sense the presence or absence of an obstacle when moving.

The flying object 7120 has a propeller, a camera, a secondary battery, and the like, and has a function of autonomous flight.

In addition, since the remaining battery level measurement circuit described in Embodiment 1 connected to the secondary battery of the aircraft 7120 is included, the charging state of the secondary battery can be accurately known.

The cleaning robot 7140 has a secondary battery, a display arranged on the top surface, a plurality of cameras arranged on the side surface, a brush, operation buttons, various sensors, and the like. Although not shown, the cleaning robot 7300 is provided with tires, a suction port, and the like. The cleaning robot 7300 can run by itself, detect dust, and suck the dust from a suction port provided on the bottom surface. Since the secondary battery protection circuit of the cleaning robot 7140 includes the remaining battery level measurement circuit described in Embodiment 1, the charged state of the secondary battery can be accurately known.

An electric vehicle 7160 is shown as an example of a mobile object. An electric vehicle 7160 has a secondary battery, tires, brakes, a steering device, a camera, and the like. Since the battery level measurement circuit described in Embodiment 1 is included in the protection circuit connected to the secondary battery of the electric vehicle 7160, the charged state of the secondary battery can be accurately known.

In addition, although an electric vehicle is described above as an example of a mobile object, the mobile object is not limited to an electric vehicle. For example, moving bodies include trains, monorails, ships, flying bodies (helicopters, unmanned aerial vehicles (drones), airplanes, rockets), etc., and a secondary battery protection circuit for these moving bodies can also be used. 1, it is possible to accurately know the state of charge of the secondary battery.

Electronic component 700 and/or electronic component 730 can be incorporated into smart phone 7210, PC 7220 (personal computer), game console 7240, and the like.

A smartphone 7210 is an example of a mobile information terminal. A smartphone 7210 has a microphone, a camera, a speaker, various sensors, and a display portion. Electronic components 730 control these peripherals. Since the battery level measurement circuit described in Embodiment 1 is included in the protection circuit of one embodiment of the present invention electrically connected to the secondary battery of the smartphone 7210, the charging state of the secondary battery can be accurately known. .

Each PC7220 is an example of a notebook PC. Since the battery level measurement circuit described in Embodiment 1 is included in the protection circuit of one embodiment of the present invention electrically connected to the secondary battery of the notebook PC, the charged state of the secondary battery can be accurately known. can.

Game machine 7240 is an example of a handheld game machine. The game machine 7260 is an example of a home-use stationary game machine. A controller 7262 is wirelessly or wiredly connected to the game machine 7260 . By incorporating the remaining battery level measurement circuit described in Embodiment 1 into electronic component 700 and/or electronic component 730 in controller 7262, the charged state of the secondary battery can be accurately known.

This embodiment can be implemented in appropriate combination with the structures described in other embodiments and the like.

(Embodiment 6)
In this embodiment, a market image in which an OS transistor can be used will be described.

<Market image>
First, FIG. 16 shows a market image in which an OS transistor can be used. In FIG. 16, an area 701 represents a product area (OS Display) that can be applied to a display using an OS transistor, and an area 702 represents an analog LSI (Large Scale Integration) using an OS transistor. An area 703 represents a product area (OS LSI analog) that can be applied to processing, and an area 703 represents a product area (OS LSI digital) that can apply an LSI using an OS transistor to digital processing. OS transistors can be suitably used in three areas, areas 701, 702, and 703 shown in FIG. 16, in other words, three large markets.

In FIG. 16, a region 704 represents a region where the regions 701 and 702 overlap, a region 705 represents a region where the regions 702 and 703 overlap, and a region 706 represents the regions 701 and 703. A region 703 represents an overlapping region, and a region 707 represents an overlapping region of the regions 701, 702, and 703, respectively.

In OS displays, for example, FET structures such as a bottom gate type OS FET (BG OSFET) and a top gate type OS FET (TG OS FET) can be preferably used. Bottom gate OS FETs include channel etch FETs and channel protection FETs. The top gate type OS FET also includes a TGSA (top gate self-aligned) type FET.

Also, in OS LSI analog and OS LSI digital, for example, a gate-last type OS FET (GL OS FET) can be preferably used.

Note that each of the transistors described above includes a single gate transistor with one gate electrode, a dual gate transistor with two gate electrodes, and a transistor with three or more gate electrodes. Among dual gate transistors, it is particularly preferable to use a transistor with an S-channel (surrounded channel) structure.

Products included in the OS Display (area 701) include products having LCDs (liquid crystal displays), ELs (Electro Luminescence), and LEDs (Light Emitting Diodes) as display devices. Alternatively, it is also preferable to combine the above display device with Q-Dots (Quantum Dots).

Note that in this embodiment, EL includes organic EL and inorganic EL. In addition, in the present embodiment, LEDs include micro LEDs, mini LEDs, and macro LEDs. In this specification and the like, light emitting diodes with a chip area of 10000 μm ² or less are micro LEDs, light emitting diodes with a chip area of 10000 μm ² or more and 1 mm ² or less are mini LEDs, and light emitting diodes with a chip area of 1 mm ² or more. is sometimes referred to as a macro LED.

Products included in the OS LSI analog (region 702) include sound source localization devices or battery Control devices (battery control ICs, battery protection ICs, battery management systems) and the like are included.

Products included in the OS LSI digital (region 703) include memory devices, CPU (Central Processing Unit) devices, GPU (Graphics Processing Unit) devices, FPGA (field-programmable gate array) devices, power devices, and OS LSIs. and a Si LSI are laminated or mixed to form a hybrid device, a light-emitting device, and the like.

Products included in area 704 include display devices having infrared sensors or near-infrared sensors in the display area, signal processing devices with sensors having OS FETs, implantable biosensor devices, and the like. Products included in the area 705 include a processing circuit including an A/D (Analog to Digital) conversion circuit, an AI (Artificial Intelligence) device including the processing circuit, and the like. Products included in the area 706 include display devices to which Pixel AI technology is applied. In this specification and the like, Pixel AI technology refers to technology that utilizes a memory configured by an OS FET or the like mounted in a pixel circuit of a display.

Products included in the area 707 include composite products that combine all the products included in the areas 701 to 706 .

As described above, the semiconductor device of one embodiment of the present invention can be applied to any product region as shown in FIG. That is, the semiconductor device of one embodiment of the present invention can be applied to many markets.

This embodiment can be implemented in appropriate combination with any structure described in any of the other embodiments.

11 control circuit 101 storage element 300 transistor 311 substrate 313 semiconductor region 314a low resistance region 314b low resistance region 315 insulator 316 conductor 320 insulator 322 insulator 324 insulator 326 insulator 328 conductor 330 conductor 350 insulator 352 insulation Body 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 410 Memory element 420 Memory element 430 Memory element 440 Memory element 450 Memory element 460 Memory element 470 Memory element 500 Transistor 503 Conductor 503a Conductor 503b Conductor 505 Conductor 510 Insulator 512 Insulator 514 Insulator 516 Insulator 518 Conductor 520 Insulator 522 Insulator 524 Insulator 526 Insulator 530 Oxide 530a Oxide 530b Oxide 530c Oxide 540a Conductor 540b Conductor 542 Conductor 542a Conductor 542b Conductor 543a Region 543b Region 544 Insulator 546 Conductor 548 Conductor 550 Insulator 560 Conductive Body 560a Conductor 560b Conductor 574 Insulator 580 Insulator 581 Insulator 582 Insulator 586 Insulator 600 Capacitive element 601 Positive electrode cap 602 Battery can 603 Positive electrode terminal 604 Positive electrode 605 Separator 606 Negative electrode 607 Negative electrode terminal 608 Insulating plate 609 Insulating plate 610 Conductor 611 PTC element 612 Conductor 616 Secondary battery 617 Safety valve mechanism 618 Protective circuit board 620 Conductor 630 Insulator 640 Insulator 700 Electronic component 730 Electronic component 900 Circuit board 910 Label 911 Terminal 913 Secondary battery 914 Antenna 915 Seal 916 Layer 917 Layer 918 Antenna 920 Display device 921 Sensor 922 Terminal 930 Housing 930a Housing 930b Housing 931 Negative electrode 932 Positive electrode 933 Separator 950 Winding body 951 Terminal 952 Terminal 961 Terminal 962 Terminal 963 Terminal 7100 Robot 7120 Flying body 7140 Cleaning robot 7160 Electric vehicle 7210 Smartphone 7220 PC
7240 game machine 7260 game machine 7262 controller 7300 cleaning robot

Claims (5)

A remaining amount measuring circuit having a display circuit for displaying the remaining amount of the secondary battery,
measuring means for measuring the voltage value of the output terminal of the secondary battery;
a plurality of storage means including a transistor having an oxide semiconductor as a semiconductor layer;
a comparison circuit that compares the voltage values stored in the plurality of storage means with the voltage values obtained by the measuring means ;
Each of the plurality of storage means is a secondary battery remaining amount measuring circuit having a function of holding an analog signal. A remaining amount measuring circuit having a display circuit for displaying the remaining amount of the secondary battery,
measuring means for measuring the voltage value of the output terminal of the secondary battery;
a plurality of storage means including a transistor having an oxide semiconductor as a semiconductor layer;
a comparison circuit that compares the voltage values stored in the plurality of storage means with the voltage values obtained by the measuring means;
a level shifter circuit between the storage means and the comparison circuit ;
Each of the plurality of storage means is a secondary battery remaining amount measuring circuit having a function of holding an analog signal. A remaining amount measuring circuit having a display circuit for displaying the remaining amount of the secondary battery,
measuring means for measuring the voltage value of the output terminal of the secondary battery;
a plurality of storage means including a transistor having an oxide semiconductor as a semiconductor layer;
a comparison circuit that compares the voltage values stored in the plurality of storage means with the voltage values obtained by the measuring means ;
The plurality of storage means is a secondary battery residual capacity measurement circuit having a function of holding different analog signals generated by resistance voltage division. A remaining amount measuring circuit having a display circuit for displaying the remaining amount of the secondary battery,
measuring means for measuring the voltage value of the output terminal of the secondary battery;
a plurality of storage means including a transistor having an oxide semiconductor as a semiconductor layer;
a comparison circuit that compares the voltage values stored in the plurality of storage means with the voltage values obtained by the measuring means;
a level shifter circuit between the storage means and the comparison circuit ;
The plurality of storage means is a secondary battery residual capacity measurement circuit having a function of holding different analog signals generated by resistance voltage division. In any one of claims 1 to 4 ,
The comparison circuit is a secondary battery remaining amount measurement circuit including a transistor having an oxide semiconductor as a semiconductor layer.

Images