Secondary battery charging control circuit and abnormality detection system

Abstract

The abnormality detection system of the secondary battery detects the abnormality of the secondary battery, such as early detection of phenomena that reduce the safety of the secondary battery, and issues a warning to the user or stops the use of the secondary battery to ensure safety. The abnormality detection system of the secondary battery detects whether the temperature of the secondary battery is within the temperature range that can perform normal operations based on the temperature information obtained by the temperature sensor. When the temperature of the secondary battery is high, the cooling device is driven by the control signal of the abnormality detection system of the secondary battery. The abnormality detection system of the secondary battery includes at least a storage unit, and the storage unit has the function of maintaining an analog signal and includes a transistor using an oxide semiconductor as a semiconductor layer.

Description

Technical Field

[0001] One embodiment of the present invention relates to an article, a method or a manufacturing method. In addition, the present invention relates to a process, a machine, a product or a composition of matter. One embodiment of the present invention relates to a semiconductor device, a display device, a light-emitting device, a power storage device, a lighting device, an electronic device or a method for manufacturing the same. One embodiment of the present invention relates to a vehicle or a vehicle electronic device provided in a vehicle. In particular, one embodiment of the present invention relates to a charging control circuit for a secondary battery, a charging control method for a secondary battery, an abnormality detection system for a secondary battery and an electronic device including a secondary battery.

[0002] In this specification, the term "power storage device" refers to any element or device having a power storage function, and includes, for example, secondary batteries such as lithium ion secondary batteries, lithium ion capacitors, all-solid-state batteries, and electric double layer capacitors. Background Art

[0003] In recent years, the research and development of various power storage devices such as lithium-ion secondary batteries, lithium-ion capacitors and air batteries has become increasingly popular. In particular, with the development of the semiconductor industry for portable information terminals such as mobile phones, smart phones, tablet computers and notebook personal computers, portable music players, digital cameras, medical equipment, or new generation clean energy vehicles such as hybrid electric vehicles (HEV), electric vehicles (EV), plug-in hybrid electric vehicles (PHEV), the demand for high-output, high-energy-density lithium-ion secondary batteries has increased dramatically. As a rechargeable energy supply source, lithium-ion secondary batteries have become a necessity in the modern information society.

[0004] In portable information terminals or electric vehicles, multiple secondary batteries are connected in series or in parallel and provided with a protection circuit, and used as a battery pack (also called a battery pack). A battery pack is a container (metal can, film outer packaging) in which multiple secondary batteries are housed together with a specified circuit for easy handling of the secondary batteries. In order to manage the operating status, an ECU (Electronic Control Unit) is provided in the battery pack.

[0005] In addition, although electric vehicles are vehicles that use only an electric motor as a driving unit, there are also hybrid vehicles that have both an internal combustion engine such as an engine and an electric motor. As secondary batteries used in automobiles, multiple secondary batteries are also used as a battery pack and the multiple battery packs are arranged at the bottom of the automobile.

[0006] In addition, secondary batteries used in electric vehicles and hybrid vehicles deteriorate due to the number of times they are charged, the depth of discharge, the charging current, the charging environment (ambient temperature changes), etc. It also depends on the user's usage, and the ambient temperature during charging, the frequency of high-speed charging, the amount of charge using regenerative braking, the timing of charging using regenerative braking, etc. may also be related to deterioration.

[0007] Patent Document 1 describes that the remaining power, voltage, current, temperature, and other conditions of a secondary battery can be measured by a sensor.

[0008] [Prior technical literature]

[0009] [Patent Document]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 2014-143190 Summary of the invention

[0011] Technical problem to be solved by the invention

[0012] Electric vehicles are prone to temperature changes depending on the working state or environment, so safety measures against temperature are required. Among the onboard components of electric vehicles, secondary batteries have the most important function as the power source of electric vehicles. On the other hand, there is the following problem: the temperature range in which lithium secondary batteries can operate normally (above -20°C and below 60°C) is smaller than the allowable range of the ambient temperature (above -50°C and below 100°C) in which electric vehicles are used.

[0013] When the ambient temperature is outside the normal range, the charge and discharge performance or life of the secondary battery may be greatly affected, so it is preferred to use it at a specified ambient temperature as much as possible. In addition to the problem of the surrounding environment, when a large amount of current flows through the secondary battery during charging and discharging, the temperature of the secondary battery itself rises.

[0014] Secondary batteries have the problem that they are prone to deterioration when internal chemical reactions occur in high ambient temperatures. In addition, in extremely cold areas with ambient temperatures of -50°C, the liquid components in the secondary batteries are frozen and cannot be discharged, thereby losing their function as secondary batteries.

[0015] Not limited to extremely cold regions, the capacity of lithium-ion secondary batteries also decreases when the ambient temperature of electric vehicles is low. The lower the temperature, the higher the internal resistance and the lower the output voltage. In addition, when charging in a low ambient temperature state, electrolytic deposition of lithium metal sometimes occurs, causing rapid deterioration.

[0016] Therefore, one of the purposes of one embodiment of the present invention is to detect abnormalities of secondary batteries by using an abnormality detection system for secondary batteries, such as early detection of phenomena that reduce the safety of secondary batteries, and to issue warnings to users or stop using the secondary batteries, thereby ensuring safety.

[0017] Electric vehicles equipped with secondary batteries need to let the driver (or passenger) know the distance that can be traveled based on the information of the remaining power of the secondary battery, and estimate the distance that can be traveled in real time and accurately. In addition, sometimes an abnormality of the secondary battery suddenly occurs, causing the function of the secondary battery to stop, and it is difficult to predict the abnormality with existing methods. One embodiment of the present invention provides a control system for a secondary battery, which calculates the remaining power or internal resistance of the secondary battery of the electric vehicle, issues a warning for a secondary battery with abnormal characteristics, stops the use of the secondary battery, replaces the secondary battery, or changes the charging conditions.

[0018] One object of one embodiment of the present invention is to provide a novel battery management circuit, power storage device, electronic device, and the like.

[0019] Solutions to technical problems

[0020] The abnormality detection system of the secondary battery detects whether the temperature of the secondary battery is within the temperature range for normal operation based on the temperature information obtained by the temperature sensor and reports it to the user. When the temperature of the secondary battery is high, the cooling device is driven by the control signal of the abnormality detection system of the secondary battery. When the temperature of the secondary battery is high, a warning sound is emitted to notify the user of the danger of an impending system abnormality of the electric vehicle. In addition, when the temperature of the secondary battery is low, the heating device is driven to increase the temperature of the secondary battery before the temperature drops further and the secondary battery freezes.

[0021] The abnormality detection system for a secondary battery includes at least a storage unit having a function of holding an analog signal and including a transistor using an oxide semiconductor as a semiconductor layer. By using a transistor using an oxide semiconductor as a semiconductor layer, an abnormality detection system that realizes low power consumption can be manufactured.

[0022] The charging control circuit of the secondary battery disclosed in this specification includes: a temperature sensor for detecting the temperature of the secondary battery; a first temperature comparison circuit and a second temperature comparison circuit that generate a pulse signal by inputting an analog signal from the temperature sensor; a heating device for the secondary battery that operates within two temperature ranges set by the first temperature comparison circuit; and a cooling device for the secondary battery that operates within two temperature ranges set by the second temperature comparison circuit.

[0023] In the above structure, the first temperature comparison circuit or the second temperature comparison circuit includes a comparator having two thresholds.

[0024] In the above configuration, the charging control circuit of the secondary battery controls the opening and closing of the switch for interrupting the charging current of the secondary battery.

[0025] In the above structure, the charge control circuit of the secondary battery includes at least a memory cell, and the memory cell has a function of holding an analog signal and includes a transistor using an oxide semiconductor as a semiconductor layer.

[0026] In addition, as a structure of other inventions, the charging control circuit of the secondary battery disclosed in this specification includes: a temperature sensor for detecting the temperature of the secondary battery; a temperature comparison circuit that generates a pulse signal by inputting an analog signal from the temperature sensor; an audio device that operates within a temperature range set using the temperature comparison circuit; and a storage unit, wherein the temperature comparison circuit includes a comparator having two thresholds, and the storage unit has a function of maintaining an analog signal and includes a transistor using an oxide semiconductor as a semiconductor layer.

[0027] In the above-mentioned structures, the secondary battery charge control circuit is a secondary battery charge control circuit provided on a printed circuit board.

[0028] In addition, the disclosed secondary battery abnormality detection system includes the following steps: using a charging control circuit to make settings so that the temperature adjustment device of the secondary battery is driven only within a specified temperature range; closing a switch for blocking the charging current of the secondary battery to charge the secondary battery; using a temperature sensor to detect the temperature of the secondary battery; when the temperature of the secondary battery reaches the upper limit of the set temperature range, closing the switch for blocking the charging current of the secondary battery to stop charging; and driving the temperature adjustment device in a manner so that the temperature of the secondary battery is within the set temperature range, that is, below the upper limit temperature to lower the temperature of the secondary battery.

[0029] In addition, the disclosed secondary battery abnormality detection system includes the following steps: using a charging control circuit to make settings so that the temperature adjustment device of the secondary battery is only driven within a specified temperature range; using a temperature sensor to detect the temperature of the secondary battery; and when the temperature of the secondary battery is outside the set temperature range (a temperature below the lower limit temperature or a temperature above the upper limit temperature), an audio device is activated to sound an alarm.

[0030] In the above configuration, the temperature range in which the alarm is issued is 45° C. or higher and 60° C. or lower, or -50° C. or higher and 10° C. or lower.

[0031] The above temperature range does not refer to the external air temperature of electric vehicles, etc., but refers to the temperature around the outer packaging of the secondary battery. In many cases, the outer packaging (including laminated films, sealed cans) is made of materials with good heat dissipation. When the thickness of the outer packaging is less than 1 mm, it can be considered that the temperature on the surface of the outer packaging is roughly equal to the temperature inside the secondary battery. In addition, depending on the internal structure of the secondary battery, the configuration of the leads, and the sealing method, there are sometimes locations where the temperature is prone to rise locally. The temperature sensor of the secondary battery is preferably set at a location where the temperature is prone to rise.

[0032] In addition, other structures of the disclosed secondary battery abnormality detection system include the following steps: using a charging control circuit to make settings so that the temperature adjustment device of the secondary battery is driven only within a specified temperature range; closing a switch for cutting off the charging current of the secondary battery and charging the secondary battery; using a temperature sensor to detect the temperature of the secondary battery; when the temperature of the secondary battery reaches the lower limit of the set temperature range, turning on a switch for cutting off the charging current of the secondary battery and stopping charging; and driving the temperature adjustment device to increase the temperature of the secondary battery in such a manner that the temperature of the secondary battery is within the set temperature range and higher than the lower limit.

[0033] Effects of the Invention

[0034] The secondary battery abnormality detection system disclosed in this specification detects abnormalities in the secondary battery, for example, predicts phenomena that reduce the safety of the secondary battery, issues a warning to the user, or changes the operating conditions of the secondary battery to ensure safety.

[0035] In addition, the secondary battery abnormality detection system disclosed in this specification detects abnormal temperature of the secondary battery and issues a warning to the user, thereby avoiding a serious situation.

[0036] The secondary battery abnormality detection system disclosed in this specification can expand the temperature range in which the battery can operate normally in an environment where an electric vehicle is used.

[0037] BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a block diagram showing one embodiment of the present invention.

[0039] Figure 2A , Figure 2B This is a block diagram showing one embodiment of the present invention.

[0040] Figure 3 This is a block diagram showing one embodiment of the present invention.

[0041] Figure 4A is a block diagram showing an electric vehicle according to one embodiment of the present invention. Figure 4B It is a perspective view of a secondary battery.

[0042] Figure 5 This is a block diagram showing one embodiment of the present invention.

[0043] Fig. 6A , Figure 6B , Figure 6C , Fig.6D , Fig. 6E , Fig. 6F , Figure 6G A diagram illustrating an example of a circuit configuration of a memory.

[0044] Figure 7 is a cross-sectional view illustrating an example of a transistor.

[0045] Figure 8 is a cross-sectional view illustrating an example of a transistor.

[0046] Fig.9A , Fig. 9B , Fig. 9C is a cross-sectional view illustrating an example of a transistor.

[0047] Fig.10 This is a block diagram showing one embodiment of the present invention.

[0048] Fig.11A , Fig. 11B , Fig. 11C It is a diagram showing an example of a moving object.

[0049] Fig. 12A , Fig. 12B is a perspective view showing an example of a secondary battery, Fig. 12C This is a model diagram of a secondary battery during charging.

[0050] Modes for Carrying Out the Invention

[0051] Below, the embodiments of the present invention are described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following description, and a person skilled in the art can easily understand that the method and details can be transformed into various forms. In addition, the present invention should not be interpreted as being limited to the contents described in the following embodiments.

[0052] (Implementation Method 1)

[0053] Figure 1The following is a block diagram showing the entire abnormality detection system BTOS (Battery operating system or Battery oxide semiconductor) (BMS: Battery Management System) of a secondary battery (hereinafter, also referred to as a battery) that performs temperature control.

[0054] exist Figure 1 In the figure, the vehicle 140 is a part other than the abnormality detection system in the electric vehicle and includes a control circuit other than the charging control circuit, an air conditioner, and the like.

[0055] The abnormality detection system 110 at least includes a charging control circuit and a storage unit.

[0056] The temperature of the first battery 121 is measured by the temperature sensor 122 and the temperature is managed by the abnormality detection system 110. During charging, if the temperature rises and exceeds the allowable range, a control signal is input from the abnormality detection system 110 to the current interruption switch 123 to stop charging. In addition, if the temperature rises and exceeds the allowable range, a command signal is input from the abnormality detection system 110 to the cooling device 131 to reduce the temperature of the first battery 121. In addition, if the temperature drops and falls below the allowable range, a command signal is input from the abnormality detection system 110 to the heating device 132 to increase the temperature of the first battery 121. The temperature control device 130 of the secondary battery includes a cooling device 131 and a heating device 132.

[0057] Note that, specifically, the abnormality detection system 110 refers to an aggregate of a plurality of ICs (CPUs, etc.) and the like provided on a printed circuit board or the like.

[0058] The abnormality detection system 110 performs temperature management of the first battery through analog signal processing or digital signal processing.

[0059] When using analog signals to detect temperature, such as Figure 2A As shown, the temperature detection circuit 111 can detect the temperature state of the battery by using the output signal (temperature information) of the temperature sensor as an analog signal. The temperature data of the battery is input to the abnormality detection system 110 as analog data from the temperature sensor (From temperature sensor), and the temperature control signal as a digital signal is output to the temperature control device (To temperature control device).

[0060] The temperature sensor 122 may be, for example, a Figure 6C The circuit of the storage element 430 shown in the figure performs temperature detection. Oxide semiconductors have the property that the higher the temperature, the lower the resistance value. This property can be used to convert the ambient temperature into a potential. Figure 6CWhen the storage element 430 shown is used, the transistor M1 is first turned on and 0V is supplied to the wiring BL, and 0V is written to the node ND. Then, VDD is supplied to the wiring BL and the transistor M1 is turned off after a certain period of time. The resistance value of the oxide semiconductor changes with temperature. Therefore, the potential corresponding to the ambient temperature at the time of measurement (also referred to as "ambient temperature information") is maintained in the node ND. In addition, the higher the ambient temperature, the higher the potential maintained in the node ND.

[0061] As such, the memory element 430 may be used as a temperature sensor.

[0062] Even without using the memory element 430, the temperature sensor 122 may use a thermistor having a characteristic that depends on temperature. As the thermistor, an NTC (Negative Temperature Coefficient) thermistor, a PTC (Positive Temperature Coefficient) thermistor, or the like may be used.

[0063] The battery voltage input to the protection circuit 112 is supplied as an analog potential, and a comparator is used to monitor abnormal operations such as overcharge, overdischarge, overcharge current, overdischarge current, etc. When an abnormality is detected, the switch control signal is used as logic to close the power supply cutoff switch (non-conductive).

[0064] In addition, when using digital signals to detect temperature, such as Figure 2B As shown, ADC113 converts the battery temperature (analog signal) into a digital signal and outputs it. The temperature detection operation circuit 114 generates and outputs a control signal for operating the temperature control device 130 by operating (identifying, detecting) the input digital signal. For example, by generating a pulse signal for carefully controlling the opening and closing of the temperature control device as a temperature control signal, the battery temperature can be fine-tuned or intermittently controlled. The temperature detection operation circuit 114 can use a microcontroller, for example. Note that a microcontroller refers to a device that transfers a program that can execute an algorithm such as an operation to a microcomputer or a microprocessor.

[0065] For example, the temperature detection 111 can be performed by Figure 3A hysteresis comparator as shown generates a pulse signal for opening and closing control. The hysteresis comparator has two thresholds to compare the potential. The potentials of high temperature setting (high), high temperature setting (low), low temperature setting (high), and low temperature setting (low) can also be supplied from the outside to the potential corresponding to the temperature. In addition, a structure in which each potential is maintained in a storage circuit composed of transistors and capacitors using oxide semiconductors without always supplying the potential from the outside can also be adopted. Figure 6 shows an example of the structure of the storage circuit. In addition, the circuit including the storage circuit or the above-mentioned abnormality detection system 110 is sometimes referred to as BTOS (Battery operating system: battery operating system, or Battery oxide semiconductor: battery oxide semiconductor) or BMS (battery management system).

[0066] The temperature control works as follows: when the potential of the battery temperature is lower than the low temperature setting (low), the temperature control signal (heating) output by the hysteresis comparator is output as an ON signal. Then, when the potential of the battery temperature exceeds the low temperature setting (high) by heating, the temperature control signal (heating) output by the hysteresis comparator is output as an OFF signal.

[0067] Specifically, for example, by setting the threshold value in such a way that the low temperature setting (low) is set to a temperature of 0°C and heating is started, and the low temperature setting (high) is set to a temperature of 5°C and heating is stopped, temperature control work can be performed only when necessary instead of continuing to work all the time, so that power consumption can be reduced for driving.

[0068] The battery abnormality detection system disclosed in this specification can expand the temperature range in which the electric vehicle can operate normally in the environment in which the electric vehicle is used. Even if the ambient temperature changes, the battery abnormality detection system can be used to adjust the battery temperature so that the electric vehicle can be driven normally.

[0069] (Implementation Method 2)

[0070] In this embodiment, refer to Figure 4A An example of application to an electric vehicle (EV) is shown.

[0071] The electric vehicle is provided with a first battery 121 used as a secondary battery for main driving and a second battery 211 for supplying power to an inverter 212 for starting an engine 204. In the present embodiment, the battery controller 202 monitors a battery module 120 including at least a temperature sensor 122, a current interruption switch 123, and the first battery 121. The battery module 120 is sometimes also referred to as a battery pack.

[0072] The first battery 121 mainly supplies power to 42V series (high voltage series) vehicle-mounted equipment, while the second battery 211 supplies power to 14V series (low voltage series) vehicle-mounted equipment. In many cases, the second battery 211 adopts a lead-acid battery because of cost advantages. However, lead-acid batteries have the disadvantages of large self-discharge compared to lithium-ion secondary batteries and easy deterioration due to a phenomenon called sulfation. Although there is an advantage of no need for maintenance when using a lithium-ion secondary battery as the second battery 211, an abnormality that cannot be distinguished during manufacturing may occur when it is used for a long period of time, such as more than three years. In particular, in order to prevent the situation that the second battery 211 of the starting inverter cannot work and the engine cannot be started even if the first battery 121 has residual capacity, when the second battery 211 is a lead-acid battery, power is supplied from the first battery to the second battery to charge in a manner that always maintains a fully charged state.

[0073] This embodiment shows an example in which a lithium ion secondary battery is used as the first battery 121. A lead acid battery or an all-solid battery is used as the second battery 211.

[0074] Reference Fig. 12A and Fig. 12B An example of a cylindrical secondary battery is described below. Fig. 12B As shown, the top surface of the cylindrical secondary battery 616 includes a positive electrode cover (battery cover) 601, and the side and bottom surfaces thereof include a battery can (outer can) 602. These positive electrode cover and battery can (outer can) 602 are insulated by a gasket (insulating gasket) 610.

[0075] Fig. 12B 604 and 606, sandwiching a separator 605. Although not shown in the figure, the battery element is wound around the center pin. One end of the battery can 602 is closed and the other end is open. As the battery can 602, metals such as nickel, aluminum, titanium, etc., which are resistant to corrosion by the electrolyte, their alloys, or alloys of them and other metals (such as stainless steel, etc.) can be used. In addition, in order to prevent corrosion caused by the electrolyte, the battery can 602 is preferably covered with nickel or aluminum. On the inside of the battery can 602, the battery element in which the positive electrode, the negative electrode and the separator are wound is sandwiched by a pair of opposing insulating plates 608 and insulating plates 609. In addition, a non-aqueous electrolyte (not shown) is injected into the interior of the battery can 602 in which the battery element is provided. Secondary batteries are composed of a positive electrode including active materials such as lithium cobalt oxide (LiCoO2) and lithium iron phosphate (LiFePO4), a negative electrode made of carbon materials such as graphite that can absorb and release lithium ions, and a non-aqueous electrolyte in which a supporting electrolyte composed of a lithium salt such as LiBF4 and LiPF6 is dissolved in an organic solvent such as ethylene carbonate or diethyl carbonate.

[0076] Because the positive electrode and negative electrode used for the cylindrical secondary battery are wound, the active material is preferably formed on both surfaces of the current collector. The positive electrode 604 is connected to the positive terminal (positive electrode current collector lead) 603, and the negative electrode 606 is connected to the negative terminal (negative electrode current collector lead) 607. Both the positive terminal 603 and the negative terminal 607 can use metal materials such as aluminum. The positive terminal 603 is resistance-welded to the safety valve mechanism 617, and the negative terminal 607 is resistance-welded to the bottom of the battery can 602. The safety valve mechanism 617 is electrically connected to the positive electrode cover 601 through the PTC (Positive Temperature Coefficient) element 611. When the internal pressure of the battery rises to exceed a specified threshold, the safety valve mechanism 617 cuts off the electrical connection between the positive electrode cover 601 and the positive electrode 604. In addition, the PTC element 611 is a thermistor whose resistance increases when the temperature rises, and limits the current by increasing the resistance to prevent abnormal heating. Barium titanate (BaTiO 3 ) based semiconductor ceramics or the like can be used for the PTC element.

[0077] A lithium-ion secondary battery using an electrolyte includes a positive electrode, a negative electrode, a separator, an electrolyte, and an outer package. Note that in a lithium-ion secondary battery, since the anode and the cathode are swapped according to charging or discharging, and the oxidation reaction and the reduction reaction are swapped, the electrode with a high reaction potential is called the positive electrode, and the electrode with a low reaction potential is called the negative electrode. Therefore, in this specification, the positive electrode is called the "positive electrode" or "+ pole", and the negative electrode is called the "negative pole" or "- pole" even when charging, discharging, reverse pulse current flowing, and charging current flowing. If the terms of anode and cathode related to oxidation reaction and reduction reaction are used, the anode and cathode are opposite during charging and discharging, which may cause confusion. Therefore, in this specification, the terms of anode and cathode are not used. When the terms of anode and cathode are used, it is clearly indicated whether it is charging or discharging, and whether it corresponds to the positive electrode (+ pole) or the negative electrode (- pole).

[0078] Fig. 12C The two terminals shown are connected to a charger to charge the battery 1400. As the battery 1400 is charged, the potential difference between the electrodes increases. Fig. 12C In the embodiment, the positive direction of the current is the direction of the current flowing from the terminal outside the battery 1400 to the positive electrode 1402, and from the positive electrode 1402 to the negative electrode 1404 side in the battery 1400, and from the negative electrode to the terminal side outside the battery 1400. In other words, the direction in which the charging current flows is set as the direction of the current. The battery 1400 includes an electrolyte 1406 between the positive electrode 1402 and the negative electrode 1404 and includes a separator 1408.

[0079] In this embodiment, an example of a lithium-ion secondary battery is shown, but it is not limited to a lithium-ion secondary battery. As a positive electrode material of the secondary battery, for example, a material containing element A, element X and oxygen can be used. Element A is preferably an element selected from one or more of the first group elements and the second group elements. As the first group element, for example, alkali metals such as lithium, sodium, and potassium can be used. In addition, as the second group element, for example, calcium, beryllium, magnesium, etc. can be used. As element X, for example, one or more elements selected from metal elements, silicon and phosphorus can be used. In addition, element X is preferably an element selected from one or more of cobalt, nickel, manganese, iron and vanadium. Typically, lithium manganate, lithium cobalt composite oxide (LiCoO2) and lithium iron phosphate (LiFePO4) can be cited.

[0080] The negative electrode includes a negative electrode active material layer and a negative electrode current collector. In addition, the negative electrode active material layer may also include a conductive auxiliary agent and a binder.

[0081] As the negative electrode active material, an element that can perform a charge-discharge reaction by alloying / de-alloying reaction with lithium can be used. For example, a material containing at least one of silicon, tin, gallium, aluminum, germanium, lead, antimony, bismuth, silver, zinc, cadmium and indium can be used. The capacitance of such an element is greater than that of carbon, and in particular, the theoretical capacitance of silicon is large, which is 4200 mAh / g.

[0082] In addition, the secondary battery preferably includes a separator. As the separator, for example, a separator formed of cellulose fibers such as paper, nonwoven fabrics, glass fibers, ceramics, or synthetic fibers containing nylon (polyamide), vinylon (polyvinyl alcohol-based fibers), polyester, acrylic resin, polyolefin, polyurethane, etc. can be used.

[0083] In addition, the regenerative energy caused by the rotation of the tire 216 is transmitted to the engine 204 through the transmission 205 , and is charged to the second battery 211 or the first battery 121 from the engine controller 203 and the battery controller 202 .

[0084] In addition, the first battery 121 is mainly used to rotate the engine 204, and also supplies power to the 42V series vehicle-mounted components (the cooling device 131 of the first battery 121, the heating device 132 of the first battery 121, the electric power steering system, the defogger, etc.) through the DCDC circuit 206. In the case where the rear wheels include a rear engine, the first battery 121 is used to rotate the rear engine.

[0085] Furthermore, the second battery 211 supplies electric power to 14V series vehicle-mounted components (audio control device 151 , audio speakers, power windows, lights, etc.) through the DCDC circuit 210 .

[0086] In addition, the first battery 121 is composed of a plurality of secondary batteries. For example, Fig. 12AThe cylindrical secondary battery 616 is shown. Figure 4B As shown in FIG. 6 , a cylindrical secondary battery 616 may be sandwiched between a conductive plate 613 and a conductive plate 614 to form a battery pack. Figure 4B The switches between the secondary batteries are not shown in the figure. The plurality of secondary batteries 616 may be connected in parallel or in series, or may be connected in parallel and then in series. By forming a battery pack including the plurality of secondary batteries 616, a large amount of electric power can be obtained.

[0087] In order to cut off the power from the plurality of secondary batteries, the vehicle-mounted secondary battery includes a charging plug or a circuit breaker that can cut off the high voltage without using a tool, which is provided at the first battery 121. For example, in the case of connecting 48 battery packs including 2 to 10 units in series, a charging plug or a circuit breaker is included between the 24th and 25th battery packs.

[0088] FIG. 11 illustrates a vehicle using the secondary battery abnormality detection system which is one embodiment of the present invention. Fig.11A The secondary battery 8024 of the automobile 8400 shown in the figure can not only drive the electric motor 8406, but also supply power to the lighting devices such as the headlight 8401 or the interior light (not shown). Fig. 12B The battery pack shown is a battery pack in which a cylindrical secondary battery 616 is sandwiched between a conductive plate 613 and a conductive plate 614 .

[0089] exist Fig. 11B In the illustrated automobile 8500 , the secondary battery included in the automobile 8500 can be charged by receiving electric power from an external charging device using a plug-in method or a contactless power supply method. Fig. 11B The case where a secondary battery 8024 installed in a car 8500 is charged from a ground-mounted charging device 8021 through a cable 8022 is shown. When charging is performed, the charging method or the specifications of the connector, etc., can be appropriately performed in accordance with the provisions of CHAdeMO (registered trademark) or a combined charging system, etc. As the charging device 8021, a charging station set up in a commercial facility or a home power supply can also be used. For example, by supplying power from the outside using plug-in technology, the secondary battery 8024 installed in the car 8500 can be charged. Charging can be performed by converting AC power into DC power through a conversion device such as an AC / DC converter.

[0090] In addition, although not shown in the figure, it is also possible to install a power receiving device in the vehicle and supply power contactlessly from a power transmission device on the ground for charging. When a contactless power supply method is used, by assembling a power transmission device in a road or an outer wall, charging can be performed not only when the vehicle is parked but also when it is driving. In addition, the contactless power supply method can also be used to send and receive power between vehicles. Furthermore, a solar cell can be set on the outside of the vehicle to charge the secondary battery when the vehicle is parked or driving. Such contactless power supply can be achieved using an electromagnetic induction method or a magnetic field resonance method.

[0091] Fig. 11C This is an example of a two-wheeled vehicle using the secondary battery of one embodiment of the present invention. Fig. 11C The small motorcycle 8600 shown includes a secondary battery 8602, a rearview mirror 8601, and a turn signal light 8603. The secondary battery 8602 can supply power to the turn signal light 8603.

[0092] In addition, Fig. 11C In the illustrated scooter 8600, the secondary battery 8602 can be stored in the under-seat storage box 8604. Even if the under-seat storage box 8604 is small, the secondary battery 8602 can be stored in the under-seat storage box 8604. In addition, the present embodiment can also be applied as a power source for a snowmobile or a water motorcycle instead of a scooter.

[0093] This embodiment mode can be combined with the description of other embodiment modes as appropriate.

[0094] (Implementation 3)

[0095] In this embodiment, FIG. 6A to FIG. 6G An example of a circuit structure of a memory cell is shown. FIG. 6A to FIG. 6G Each is used as a storage element. Fig. 6A The illustrated memory element 410 includes a transistor M1 and a capacitor CA. The memory element 410 is a memory element including one transistor and one capacitor.

[0096] The first terminal of the transistor M1 is connected to the first terminal of the capacitor CA, the second terminal of the transistor M1 is connected to the wiring BL, the gate of the transistor M1 is connected to the wiring WL, and the back gate of the transistor M1 is connected to the wiring BGL. The second terminal of the capacitor CA is connected to the wiring CAL. The node electrically connecting the first terminal of the transistor M1 and the first terminal of the capacitor CA is called a node ND.

[0097] In an actual transistor, the gate and the back gate overlap each other across the channel formation region of the semiconductor layer. Both the gate and the back gate can be used as gates. Therefore, one of them is sometimes called a "back gate" and the other is sometimes called a "gate" or "front gate". In addition, one of them is sometimes called a "first gate" and the other is sometimes called a "second gate".

[0098] The potential of the back gate may be equal to that of the gate, or may be ground potential or any other potential. In addition, by changing the potential of the back gate independently without being linked to the gate, the threshold voltage of the transistor can be changed.

[0099] By providing a back gate and setting the gate and back gate potentials to be equal, the region in the semiconductor layer where carriers flow is further expanded in the film thickness direction, so the amount of carrier migration increases. As a result, the on-state current of the transistor increases and the field effect mobility also increases.

[0100] Therefore, a transistor having a large on-state current relative to its occupied area can be manufactured. In other words, the occupied area of ​​the transistor relative to the required on-state current can be reduced. Therefore, a semiconductor device with a high degree of integration can be realized.

[0101] The wiring BGL is used as a wiring for supplying a potential to the back gate of the transistor M1. By supplying an arbitrary potential to the wiring BGL, the threshold voltage of the transistor M1 can be increased or decreased.

[0102] Data writing and reading are performed by supplying a high-level potential to the wiring WL to turn on the transistor M1 and electrically connect the wiring BL to the node ND.

[0103] The wiring CAL is used as a wiring for supplying a predetermined potential to the second terminal of the capacitor CA. It is preferable that a fixed potential is supplied to the wiring CAL.

[0104] Figure 6B The memory element 420 shown is a modified example of the memory element 410. In the memory element 420, the back gate of the transistor M1 is electrically connected to the wiring WL. By having such a structure, the same potential as 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 when the transistor M1 is in the on state can be increased.

[0105] In addition, if Figure 6C As shown in the storage element 430 in FIG. 1 , the transistor M1 may also be a single-gate structure transistor (a transistor not including a back gate). The storage element 430 has a structure in which the back gate is removed from the transistor M1 of the storage element 410 and the storage element 420. Therefore, the storage element 430 can shorten the manufacturing process compared with the storage element 410 and the storage element 420.

[0106] The memory element 410 , the memory element 420 , and the memory element 430 are DRAM type memory elements.

[0107] It is preferable that an oxide semiconductor be used in the semiconductor layer forming a channel of the transistor M1. In this specification and the like, a transistor including an oxide semiconductor in the semiconductor layer forming a channel is also referred to as an "OS transistor".

[0108] For example, as an oxide semiconductor, an oxide semiconductor containing indium, an element M (the element M is one or more selected from aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten and magnesium, etc.) and zinc can be used. In particular, the oxide semiconductor preferably contains indium, gallium and zinc.

[0109] The OS transistor has a characteristic of extremely small off-state current. By using the OS transistor as the transistor M1, the leakage current of the transistor M1 can be made very small. In other words, the transistor M1 can be used to maintain the written data for a long time. Thus, the refresh frequency of the storage element can be reduced. In addition, the refresh work of the storage element can be omitted. In addition, since the leakage current is very small, multi-value data or analog data can be maintained in the storage element 410, the storage element 420, and the storage element 430.

[0110] In this specification and the like, a DRAM using an OS transistor is referred to as a DOSRAM (Dynamic Oxide Semiconductor Random Access Memory).

[0111] Fig.6D The circuit configuration example of a gain unit type memory element composed of two transistors and one capacitor is shown. The memory element 440 includes a transistor M1, a transistor M2, and a capacitor CA.

[0112] The first terminal of the transistor M1 is connected to the first terminal of the capacitor CA, the second terminal of the transistor M1 is connected to the bit line WBL, and the gate of the transistor M1 is connected to the word line WWL. The second terminal of the capacitor CA is connected to the wiring CAL. The first terminal of the transistor M2 is connected to the bit line RBL, the second terminal of the transistor M2 is connected to the word line RWL, and the gate of the transistor M2 is connected to the first terminal of the capacitor CA. The node electrically connected to the first terminal of the transistor M1, the first terminal of the capacitor CA, and the gate of the transistor M2 is called a node ND.

[0113] Bit line WBL is used as a write bit line, bit line RBL is used as a read bit line, word line WWL is used as a write word line, and word line RWL is used as a read word line. Transistor M1 is used as a switch that connects or disconnects node ND and bit line WBL.

[0114] As transistor M1, an OS transistor is preferably used. As described above, the off-state current of an OS transistor is very small, so by using an OS transistor as transistor M1, the potential written to node ND can be retained for a long time. In other words, data written to the storage element can be retained for a long time.

[0115] There is no particular limitation on the transistor used as the transistor M2. As the transistor M2, an OS transistor, a Si transistor (a transistor using silicon in a semiconductor layer), or other transistors may be used.

[0116] In addition, when the transistor M2 uses a Si transistor, the silicon used for the semiconductor layer can be amorphous silicon, polycrystalline silicon, low temperature polycrystalline silicon (LTPS: Low Temperature Poly-Silicon) or single crystal silicon. Since the field effect mobility of Si transistors is sometimes higher than that of OS transistors, when Si transistors are used as readout transistors, the operating speed during readout can be increased.

[0117] When the transistor M1 uses an OS transistor and the transistor M2 uses a Si transistor, they can also be set in different layers. The OS transistor can be made using the same manufacturing equipment and process as the Si transistor. Therefore, it is easy to mix and install the OS transistor and the Si transistor (hybridization), and it is easy to achieve high integration.

[0118] In addition, when the transistor M2 uses an OS transistor, the leakage current when not selected can be extremely small, thereby improving the readout accuracy. By using OS transistors as both the transistor M1 and the transistor M2, the manufacturing process of the semiconductor device can be reduced and the productivity can be improved. For example, the semiconductor device can also be manufactured at a process temperature below 400°C.

[0119] FIG. 6E to FIG. 6G The following is a circuit configuration example in which a transistor having a back gate (a four-terminal transistor, also referred to as a “four-terminal element”) is used as the transistor M1 and the transistor M2 . Fig. 6E The storage element 450 shown, Fig. 6F The storage element 460 and Figure 6G The illustrated memory element 470 is a modified example of the memory element 440 .

[0120] exist Fig. 6E In the memory element 450 shown, the gate of the transistor M1 is electrically connected to the back gate, and the gate of the transistor M2 is electrically connected to the back gate.

[0121] exist Fig. 6FIn the illustrated memory element 460, 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 via the wiring BGL.

[0122] exist Figure 6G In the memory element 470 shown, 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.

[0123] The storage element 440 to the storage element 470 are 2Tr1C type storage cells. In this specification, etc., a storage device that uses an OS transistor as the transistor M1 to form a 2Tr1C type storage cell is referred to as NOSRAM (Non-volatile Oxide Semiconductor Random Access Memory). In addition, the storage element 440 to the storage element 470 can amplify the potential of the node ND in the transistor M2 and read the potential. In addition, the off-state current of the OS transistor is very small, and the potential of the node ND can be maintained for a long time. In addition, non-destructive reading can be performed while maintaining the potential of the node ND when performing a read operation.

[0124] The information stored in the memory element is information that is less frequently rewritten. Therefore, it is preferable to use a NOSRAM as the memory element, which can read information non-destructively and store it for a long time.

[0125] also, Fig. 6A , Figure 6B , FIG. 6E to FIG. 6G The transistor shown is a four-terminal element, and thus has the characteristic of being able to easily independently control input and output, compared to two-terminal elements such as MRAM (Magnetoresistive Random Access Memory), ReRAM (Resistive Random Access Memory), and phase-change memory that utilize MTJ (Magnetic Tunnel Junction) characteristics.

[0126] In addition, MRAM, ReRAM, and phase change memory sometimes undergo atomic-level structural changes when rewriting information. On the other hand, a storage device according to one embodiment of the present invention operates by charging or discharging electric charge through a transistor when rewriting information, so it has good rewriting durability and its structural changes are also small.

[0127] (Implementation 4)

[0128] In this embodiment, the structure of a transistor that can be used for the structure of the storage element described in the above embodiment is described, specifically, a structure in which transistors having different electrical characteristics are stacked. In particular, the structure of each transistor included in the storage circuit constituting the semiconductor device is described in this embodiment. By adopting this structure, the design freedom of the semiconductor device can be increased. In addition, by stacking transistors having different electrical characteristics, the integration of the semiconductor device can be improved.

[0129] Figure 7 The semiconductor device shown includes a transistor 300 , a transistor 500 , and a capacitor 600 . Fig.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, Fig. 9C is a cross-sectional view of the transistor 300 in the channel width direction.

[0130] The transistor 500 is a transistor (OS transistor) including an oxide semiconductor in a channel formation region. Since the off-state current of the transistor 500 is small, by using the transistor as an OS transistor included in a semiconductor device, the written data voltage or charge can be maintained for a long period of time. In other words, the frequency of the refresh operation is low or the refresh operation is not required, so the power consumption of the semiconductor device can be reduced.

[0131] like Figure 7 As shown, the semiconductor device described in this embodiment includes a transistor 300, a transistor 500, and a capacitor 600. The transistor 500 is provided above the transistor 300, and the capacitor 600 is provided above the transistor 300 and the transistor 500. The capacitor 600 may be a capacitor in a memory circuit or the like.

[0132] The transistor 300 is provided on a substrate 311 and includes: a conductor 316, an insulator 315, a semiconductor region 313 formed by a portion of the substrate 311; and a low resistance region 314a and a low resistance region 314b used as a source region and a drain region. In addition, the transistor 300 can be applied to, for example, a transistor included in the memory circuit of the above-mentioned embodiment, etc.

[0133] like Fig. 9CAs shown, in the transistor 300, the conductor 316 covers the top surface and the side surface in the channel width direction of the semiconductor region 313 via the insulator 315. In this way, by making the transistor 300 have a Fin-type structure, the effective channel width increases, so the on-state characteristics of the transistor 300 can be improved. In addition, since the influence of the electric field of the gate electrode can be increased, the off-state characteristics of the transistor 300 can be improved.

[0134] In addition, the transistor 300 may be a p-channel transistor or an n-channel transistor.

[0135] The channel formation region of the semiconductor region 313, the region near it, the low resistance region 314a and the low resistance region 314b used as the source region or the drain region, etc. preferably contain semiconductors such as silicon-based semiconductors, and more preferably contain single crystal silicon. In addition, it can also be formed using materials including Ge (germanium), SiGe (silicon germanium), GaAs (gallium arsenide), GaAlAs (gallium aluminum arsenic), etc. Silicon that applies stress to the lattice and changes the interplanar spacing to control the effective mass can be used. In addition, the transistor 300 can also be a HEMT (High Electron Mobility Transistor) using GaAs and GaAlAs, etc.

[0136] The low resistance regions 314 a and 314 b contain, in addition to the semiconductor material used for the semiconductor region 313 , an element imparting n-type conductivity such as arsenic and phosphorus or an element imparting p-type conductivity such as boron.

[0137] As the conductor 316 used as the gate electrode, a conductive material such as a semiconductor material such as silicon, a metal material, an alloy material, or an oxide semiconductor material containing an element imparting n-type conductivity such as arsenic and phosphorus or an element imparting p-type conductivity such as boron can be used.

[0138] In addition, since the material of the conductor determines the work function, the threshold voltage of the transistor can be adjusted by selecting the material of the conductor. Specifically, materials such as titanium nitride or tantalum nitride are preferably used as the conductor. In order to have both conductivity and embedding properties, a stack of metal materials such as tungsten or aluminum is preferably used as the conductor, and tungsten is particularly preferred in terms of heat resistance.

[0139] Notice, Figure 7 The structure of the transistor 300 shown is only an example and is not limited to the above structure. An appropriate transistor can be used according to the circuit structure or driving method. For example, when a unipolar circuit (transistors of the same polarity such as only n-channel transistors) using only OS transistors is used in a semiconductor device, Figure 8As shown in FIG. 1 , the structure of the transistor 300 may be the same as that of the transistor 500 using an oxide semiconductor. The structure of the transistor 500 will be described later.

[0140] An insulator 320 , an insulator 322 , an insulator 324 , and an insulator 326 are stacked in this order so as to cover the transistor 300 .

[0141] As the insulator 320 , the insulator 322 , the insulator 324 , and the insulator 326 , for example, silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, aluminum oxynitride, aluminum nitride oxide, or aluminum nitride can be used.

[0142] Note that in this specification, "silicon oxynitride" refers to a material containing more oxygen than nitrogen in its composition, and "silicon nitride oxide" refers to a material containing more nitrogen than oxygen in its composition. Note that in this specification, "aluminum oxynitride" refers to a material containing more oxygen than nitrogen, and "aluminum nitride oxide" refers to a material containing more nitrogen than oxygen.

[0143] The insulator 322 may also be used as a planarization film for planarizing a step generated by the transistor 300 disposed thereunder, etc. For example, in order to improve the planarity of the top surface of the insulator 322, the top surface may be planarized by a planarization process such as chemical mechanical polishing (CMP).

[0144] Note that as the insulator 324 , a film having a barrier property that can prevent hydrogen or impurities from diffusing from the substrate 311 , the transistor 300 , or the like into a region where the transistor 500 is provided is preferably used.

[0145] As an example of a film having a barrier property against hydrogen, for example, silicon nitride formed by a CVD method can be used. Here, hydrogen sometimes diffuses into a semiconductor element having an oxide semiconductor such as transistor 500, resulting in a decrease in the characteristics of the semiconductor element. Therefore, it is preferred to provide a film that inhibits the diffusion of hydrogen between transistor 500 and transistor 300. Specifically, the film that inhibits the diffusion of hydrogen refers to a film with a small amount of hydrogen released.

[0146] The amount of hydrogen released can be measured, for example, by thermal desorption spectroscopy (TDS). For example, when the amount of hydrogen released is converted to the amount per unit area of ​​the insulator 324 when the film surface temperature in the TDS analysis is in the range of 50°C to 500°C, the amount of hydrogen released from the insulator 324 is 10×10 15 atoms / cm 2 Below, preferably 5×10 15 atoms / cm 2 The following is enough.

[0147] Note that the dielectric constant of the insulator 326 is preferably lower than that of the insulator 324. For example, the dielectric constant of the insulator 326 is preferably lower than 4, more preferably lower than 3. For example, the relative dielectric constant of the insulator 326 is preferably 0.7 times or less, more preferably 0.6 times or less, the relative dielectric constant of the insulator 324. By using a material with a low dielectric constant for the interlayer film, parasitic capacitance generated between wirings can be reduced.

[0148] In addition, conductors 328 and 330 connected to capacitor 600 and transistor 500 are embedded in insulators 320, 322, 324, and 326. In addition, conductors 328 and 330 have the function of plugs or wiring. Note that the same reference numeral is sometimes used to represent a plurality of conductors having the function of plugs or wiring. In addition, in this specification, wiring and a plug connected to wiring may also be one component. That is, a part of a conductor is sometimes used as wiring, and a part of a conductor is sometimes used as a plug.

[0149] As the material of each plug and wiring (conductor 328 and conductor 330, etc.), a single layer or a laminate of a conductive material such as a metal material, an alloy material, a metal nitride material or a metal oxide material can be used. It is preferred to use a high melting point material such as tungsten or molybdenum that has both heat resistance and conductivity, and tungsten is particularly preferred. Alternatively, it is preferred to use a low-resistance conductive material such as aluminum or copper. By using a low-resistance conductive material, the wiring resistance can be reduced.

[0150] Alternatively, a wiring layer may be formed on the insulator 326 and the conductor 330. Figure 7 In the embodiment of the present invention, an insulator 350, an insulator 352, and an insulator 354 are stacked in this order. Furthermore, a conductor 356 is formed in the insulator 350, the insulator 352, and the insulator 354. The conductor 356 has a function of a plug or wiring connected to the transistor 300. The conductor 356 can be formed using the same material as the conductor 328 and the conductor 330.

[0151] In addition, similar to the insulator 324, the insulator 350 preferably uses an insulator having a barrier property to hydrogen, for example. In addition, the conductor 356 preferably includes a conductor having a barrier property to hydrogen. In particular, the conductor having a barrier property to hydrogen is formed in the opening portion of the insulator 350 having a barrier property to hydrogen. By adopting this structure, the transistor 300 and the transistor 500 can be separated by using a barrier layer, so that the diffusion of hydrogen from the transistor 300 to the transistor 500 can be suppressed.

[0152] Note that as a conductor having a barrier property to hydrogen, for example, tantalum nitride is preferably used. Furthermore, by stacking tantalum nitride and tungsten having high conductivity, it is possible to maintain conductivity as a wiring and suppress diffusion of hydrogen from the transistor 300. At this time, the tantalum nitride layer having a barrier property to hydrogen is preferably in contact with the insulator 350 having a barrier property to hydrogen.

[0153] Alternatively, a wiring layer may be formed on the insulator 354 and the conductor 356. Figure 7 In the embodiment, an insulator 360, an insulator 362, and an insulator 364 are stacked in this order. In addition, a conductor 366 is formed in the insulator 360, the insulator 362, and the insulator 364. The conductor 366 has a function of a plug or wiring. In addition, the conductor 366 can be formed using the same material as the conductor 328 and the conductor 330.

[0154] In addition, similar to the insulator 324, the insulator 360 preferably uses an insulator having a barrier property to hydrogen. In addition, the conductor 366 preferably includes a conductor having a barrier property to hydrogen. In particular, the conductor having a barrier property to hydrogen is formed in the opening portion of the insulator 360 having a barrier property to hydrogen. By adopting this structure, the transistor 300 and the transistor 500 can be separated by using a barrier layer, so that the diffusion of hydrogen from the transistor 300 to the transistor 500 can be suppressed.

[0155] Alternatively, a wiring layer may be formed on the insulator 364 and the conductor 366. Figure 7 In the embodiment, an insulator 370, an insulator 372, and an insulator 374 are stacked in this order. In addition, a conductor 376 is formed in the insulator 370, the insulator 372, and the insulator 374. The conductor 376 has a function of a plug or wiring. In addition, the conductor 376 can be formed using the same material as the conductor 328 and the conductor 330.

[0156] In addition, similar to the insulator 324, the insulator 370 preferably uses an insulator having a barrier property to hydrogen. In addition, the conductor 376 preferably includes a conductor having a barrier property to hydrogen. In particular, the conductor having a barrier property to hydrogen is formed in the opening portion of the insulator 370 having a barrier property to hydrogen. By adopting this structure, the transistor 300 and the transistor 500 can be separated by using a barrier layer, so that the diffusion of hydrogen from the transistor 300 to the transistor 500 can be suppressed.

[0157] Alternatively, a wiring layer may be formed on the insulator 374 and the conductor 376. Figure 7In the embodiment, an insulator 380, an insulator 382, ​​and an insulator 384 are stacked in this order. In addition, a conductor 386 is formed in the insulator 380, the insulator 382, ​​and the insulator 384. The conductor 386 has a function of a plug or wiring. In addition, the conductor 386 can be formed using the same material as the conductor 328 and the conductor 330.

[0158] In addition, similar to the insulator 324, the insulator 380 preferably uses an insulator having a barrier property to hydrogen. In addition, the conductor 386 preferably includes a conductor having a barrier property to hydrogen. In particular, the conductor having a barrier property to hydrogen is formed in the opening portion of the insulator 380 having a barrier property to hydrogen. By adopting this structure, the transistor 300 and the transistor 500 can be separated by using a barrier layer, so that the diffusion of hydrogen from the transistor 300 to the transistor 500 can be suppressed.

[0159] In the above description, 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, but the semiconductor device of this embodiment is not limited thereto. The number of wiring layers similar to the wiring layer including the conductor 356 may be three or less, and the number of wiring layers similar to the wiring layer including the conductor 356 may be five or more.

[0160] An insulator 510, an insulator 512, an insulator 514, and an insulator 516 are sequentially stacked on the insulator 384. As one of the insulator 510, the insulator 512, the insulator 514, and the insulator 516, a substance having a barrier property against oxygen or hydrogen is preferably used.

[0161] For example, a film having a barrier property that can prevent hydrogen or impurities from diffusing from the substrate 311 or a region where the transistor 300 is provided into a region where the transistor 500 is provided is preferably used as the insulator 510 and the insulator 514. Therefore, the insulator 510 and the insulator 514 can use the same material as the insulator 324.

[0162] As an example of a film having a barrier property against hydrogen, silicon nitride formed by a CVD method can be used. Here, hydrogen sometimes diffuses into a semiconductor element having an oxide semiconductor such as transistor 500, resulting in a decrease in the characteristics of the semiconductor element. Therefore, it is preferred to provide a film that inhibits the diffusion of hydrogen between transistor 500 and transistor 300. Specifically, the film that inhibits the diffusion of hydrogen refers to a film with a small amount of hydrogen released.

[0163] For example, as a film having a barrier property against hydrogen, the insulator 510 and the insulator 514 are preferably made of a metal oxide such as aluminum oxide, hafnium oxide, or tantalum oxide.

[0164] In particular, aluminum oxide has a high barrier effect of preventing oxygen and impurities such as hydrogen and moisture that cause changes in the electrical characteristics of the transistor from passing through the film. Therefore, during and after the manufacturing process of the transistor, aluminum oxide can prevent impurities such as hydrogen and moisture from entering the transistor 500. In addition, aluminum oxide can suppress the release of oxygen from the oxide constituting the transistor 500. Therefore, aluminum oxide is suitable for use as a protective film for the transistor 500.

[0165] In addition, for example, the insulator 512 and the insulator 516 can use the same material as the insulator 320. In addition, by using a material with a low dielectric constant as the insulator, the parasitic capacitance generated between the wirings can be reduced. For example, as the insulator 512 and the insulator 516, a silicon oxide film, a silicon oxynitride film, or the like can be used.

[0166] In addition, for example, a conductor 518 or a conductor (for example, the conductor 503) constituting the transistor 500 is embedded in the insulator 510, the insulator 512, the insulator 514, and the insulator 516. The conductor 518 is used as a plug or wiring connected to the capacitor 600 or the transistor 300. The conductor 518 can be formed using the same material as the conductors 328 and 330.

[0167] In particular, the conductor 518 in the region in contact with the insulator 510 and the insulator 514 is preferably a conductor having a barrier property to oxygen, hydrogen, and water. By adopting this structure, the transistor 300 and the transistor 500 can be separated by a layer having a barrier property to oxygen, hydrogen, and water, thereby suppressing the diffusion of hydrogen from the transistor 300 to the transistor 500.

[0168] The transistor 500 is provided above the insulator 516 .

[0169] like Fig.9A and Fig. 9B As shown, transistor 500 includes: a conductor 503 embedded in an insulator 514 and an insulator 516; an insulator 520 arranged on the insulator 516 and the conductor 503; an insulator 522 arranged on the insulator 520; an insulator 524 arranged on the insulator 522; an oxide 530a arranged on the insulator 524; an oxide 530b arranged on the oxide 530a; a conductor 542a and a conductor 542b arranged on the oxide 530b and separated from each other; an insulator 580 arranged on the conductor 542a and the conductor 542b and having an opening overlapping with the conductor 542a and the conductor 542b; 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 a conductor 560 arranged on the formation surface of the insulator 550.

[0170] In addition, if Fig.9A and Fig. 9B As shown in FIG. 5 , an insulator 544 is preferably disposed between the oxide 530a, the oxide 530b, the conductor 542a, the conductor 542b, and the insulator 580. Fig.9A and Fig. 9B As shown in FIG. 5 , the conductor 560 preferably includes a conductor 560a disposed inside the insulator 550 and a conductor 560b embedded inside the conductor 560a. Fig.9A and Fig. 9B As shown, an insulator 574 is preferably arranged on the insulator 580 , the conductor 560 , and the insulator 550 .

[0171] Note that below, the oxide 530 a , the oxide 530 b , and the oxide 530 c may be collectively referred to as an oxide 530 .

[0172] Note that in transistor 500, three layers of oxide 530a, oxide 530b, and oxide 530c are stacked in the region where the channel is formed and in the vicinity thereof, but the present invention is not limited to this. For example, a single layer of oxide 530b, a two-layer structure of oxide 530b and oxide 530a, a two-layer structure of oxide 530b and oxide 530c, or a stacked structure of four or more layers may be provided. In addition, in transistor 500, conductor 560 has a two-layer structure, but the present invention is not limited to this. For example, conductor 560 may also have a single-layer structure or a stacked structure of three or more layers. Note that Figure 7 , Fig.9A The structure of the transistor 500 shown is only an example and is not limited to the above structure, and an appropriate transistor can be used according to the circuit structure or driving method.

[0173] Here, the conductor 560 is used as the gate electrode of the transistor, and the conductor 542a and the conductor 542b are used as the source electrode or the drain electrode. As described above, the conductor 560 is buried in the opening of the insulator 580 and in the area sandwiched between the conductor 542a and the conductor 542b. The configuration of the conductor 560, the conductor 542a and the conductor 542b relative to the opening of the insulator 580 is selected in a self-aligned manner. In other words, in the transistor 500, the gate electrode can be configured in a self-aligned manner between the source electrode and the drain electrode. Thus, the conductor 560 can be formed in a manner without providing room for alignment, so that the occupied area of ​​the transistor 500 can be reduced. Thus, miniaturization and high integration of semiconductor devices can be achieved.

[0174] Furthermore, since the conductor 560 is formed in a self-aligned manner in the region between the conductor 542a and the conductor 542b, the conductor 560 does not include a region overlapping with the conductor 542a and the conductor 542b. Thus, the parasitic capacitance formed between the conductor 560 and the conductor 542a and the conductor 542b can be reduced. Therefore, the switching speed of the transistor 500 can be increased, so that the transistor 500 can have high frequency characteristics.

[0175] Conductor 560 is sometimes used as a first gate (also called a top gate) electrode. Conductor 503 is sometimes used as a second gate (also called a bottom gate) electrode. In this case, the threshold voltage of transistor 500 can be controlled by independently changing the potential supplied to conductor 503 without interlocking it with the potential supplied to conductor 560. In particular, by supplying a negative potential to conductor 503, the threshold voltage of transistor 500 can be made greater than 0V and the off-state current can be reduced. Therefore, compared with when a negative potential is not applied to conductor 503, when a negative potential is applied to conductor 503, the drain current when the potential supplied to conductor 560 is 0V can be reduced.

[0176] The conductor 503 is arranged so as to overlap with the oxide 530 and the conductor 560. Thus, when a potential is supplied to the conductor 560 and the conductor 503, the electric field generated from the conductor 560 and the electric field generated from the conductor 503 are connected, and a channel formation region formed in the oxide 530 can be covered. In this specification, etc., a structure of a transistor in which a channel formation region is electrically surrounded by an electric field of a first gate electrode and an electric field of a second gate electrode is referred to as a surrounded channel (S-channel) structure.

[0177] In addition, in this specification, etc., the surrounded channel (S-channel) structure has the following characteristics, that is, the side and periphery of the oxide 530 in contact with the conductor 542a and the conductor 542b used as the source electrode and the drain electrode are I-type, as in the channel formation region. In addition, because the side and periphery of the oxide 530 in contact with the conductor 542a and the conductor 542b are in contact with the insulator 544, it is possible to become I-type, as in the channel formation region. Note that in this specification, etc., I-type can be said to be the same as the high-purity intrinsic described later. In addition, the S-channel structure disclosed in this specification, etc. is different from the Fin-type structure and the planar structure. By adopting the S-channel structure, a transistor with improved resistance to short channel effects can be realized, in other words, a transistor that is not prone to short channel effects can be realized.

[0178] In addition, the conductor 503 has the same structure as the conductor 518, and the conductor 503a is formed in contact with the inner wall of the opening of the insulator 514 and the insulator 516, and the conductor 503b is formed inside. In addition, in the transistor 500, the conductor 503a and the conductor 503b are stacked, but the present invention is not limited to this. For example, the conductor 503 may have a single-layer structure or a stacked structure of three or more layers.

[0179] Here, as the conductor 503a, it is preferable to use a conductive material having a function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, and copper atoms (not allowing the above impurities to pass through easily). In addition, it is preferable to use a conductive material having a function of suppressing the diffusion of oxygen (for example, at least one of oxygen atoms and oxygen molecules) (not allowing the above oxygen to pass through easily). In this specification, "the function of suppressing the diffusion of impurities or oxygen" means the function of suppressing the diffusion of any one or all of the above impurities and the above oxygen.

[0180] For example, by providing the conductor 503a with a function of suppressing the diffusion of oxygen, a decrease in conductivity due to oxidation of the conductor 503b can be suppressed.

[0181] In addition, when the conductor 503 also has a wiring function, it is preferable to use a highly conductive conductive material with tungsten, copper or aluminum as a main component as the conductor 503b. In this case, it is not necessary to provide the conductor 505. In the drawings, the conductor 503b has a single-layer structure, but it may also have a laminated structure, for example, a laminated structure of titanium or titanium nitride and the above conductive material may be used.

[0182] The insulator 520 , the insulator 522 , and the insulator 524 are used as a second gate insulating film.

[0183] Here, the insulator 524 in contact with the oxide 530 preferably contains oxygen exceeding the stoichiometric composition. In other words, it is preferable to form an excess oxygen region in the insulator 524. By providing the insulator containing excess oxygen in contact with the oxide 530, oxygen vacancies in the oxide 530 can be reduced, thereby improving the reliability of the transistor 500.

[0184] Specifically, as an insulator having an excess oxygen region, an oxide material from which a portion of oxygen is released by heating is preferably used. An oxide film from which oxygen is released by heating means that the amount of oxygen released in terms of oxygen atoms in TDS (Thermal Desorption Spectroscopy) analysis is 1.0×10 18 atoms / cm 3 Above, preferably 1.0×10 19 atoms / cm3 More preferably, 2.0×10 19 atoms / cm 3 Above, or 3.0×10 20 atoms / cm 3 In addition, the surface temperature of the film when performing the above-mentioned TDS analysis is preferably in the range of 100° C. to 700° C., or 100° C. to 500° C.

[0185] Alternatively, the insulator having the above-mentioned excess oxygen region may be brought into contact with the oxide 530 and subjected to one or more of a heat treatment, a microwave treatment, and an RF treatment. By performing this treatment, water or hydrogen in the oxide 530 may be removed. For example, in the oxide 530, a bond severance reaction of VoH occurs, in other words, a “V O H→V O +H" reaction can achieve dehydrogenation. A portion of the hydrogen generated here sometimes bonds with oxygen and is removed from the oxide 530 or the insulator near the oxide 530 as H2O. In addition, a portion of the hydrogen sometimes diffuses into the conductor 542 or is captured by the conductor 542 (also called being doped).

[0186] In addition, the above-mentioned microwave treatment preferably uses, for example, a device having a power to generate high-density plasma or a device that applies RF power to one side of the substrate. For example, by using a gas containing oxygen and using high-density plasma, high-density oxygen radicals can be generated, and by applying RF to one side of the substrate, the oxygen radicals generated by the high-density plasma can be effectively introduced into the oxide 530 or the insulator near the oxide 530. In addition, in the above-mentioned microwave treatment, the pressure is 133 Pa or more, preferably 200 Pa or more, and more preferably 400 Pa or more. In addition, as the gas introduced into the device for microwave treatment, for example, oxygen and argon are used, and the microwave treatment is performed under the condition that the oxygen flow ratio (O2 / (O2+Ar)) is 50% or less, preferably 10% or more and 30% or less.

[0187] In addition, in the manufacturing process of the transistor 500, it is preferable to perform heat treatment in a state where the surface of the oxide 530 is exposed. The heat treatment is preferably performed at a temperature of, for example, 100° C. or higher and 450° C. or lower, and more preferably 350° C. or higher and 400° C. or lower. The heat treatment is performed in a nitrogen gas or inert gas atmosphere or an atmosphere containing an oxidizing gas of 10 ppm or higher, 1% or higher, or 10% or higher. Therefore, oxygen can be supplied to the oxide 530 and oxygen vacancies (V O). In addition, the heat treatment may be performed under reduced pressure. Alternatively, the heat treatment may be performed under a nitrogen or inert gas atmosphere, and then the heat treatment may be performed under an atmosphere containing an oxidizing gas of 10 ppm or more, 1% or more, or 10% or more to compensate for the oxygen that has been separated. Alternatively, the heat treatment may be performed under an atmosphere containing an oxidizing gas of 10 ppm or more, 1% or more, or 10% or more, and then the heat treatment may be performed continuously under a nitrogen or inert gas atmosphere.

[0188] In addition, by performing an oxidation treatment on the oxide 530, the oxygen vacancies in the oxide 530 can be filled with the supplied oxygen. In other words, the “V O +O→null” reaction. Furthermore, the hydrogen remaining in the oxide 530 reacts with the supplied oxygen and can be removed as H2O (dehydrated). Thus, the hydrogen remaining in the oxide 530 can be prevented from being re-bonded to the oxygen vacancy to form V O H.

[0189] When the insulator 524 has an excess oxygen region, the insulator 524 preferably has a function of suppressing diffusion of oxygen (for example, oxygen atoms, oxygen molecules, etc.) (making it difficult for the oxygen to permeate).

[0190] When the insulator 522 has a function of suppressing diffusion of oxygen or impurities, it is preferable because oxygen included in the oxide 530 does not diffuse toward the insulator 520. In addition, reaction between the conductor 503 and oxygen included in the insulator 524 or the oxide 530 can be suppressed.

[0191] As the insulator 522, for example, a single layer or a stack of insulators containing so-called high-k materials such as aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium aluminate), tantalum oxide, zirconium oxide, lead zirconate titanate (PZT), strontium titanate (SrTiO3) or (Ba, Sr)TiO3 (BST) is preferably used. When miniaturization and high integration of transistors are performed, problems such as leakage current sometimes occur due to the thin film of the gate insulating film. By using a high-k material as an insulator used as a gate insulating film, the gate potential when the transistor is operating can be reduced while maintaining the physical thickness.

[0192] In particular, it is preferable to use an insulator containing an oxide of one or both of aluminum and hafnium as an insulating material having a function of suppressing the diffusion of impurities and oxygen (not allowing the above oxygen to pass easily). As an insulator containing an oxide of one or both of aluminum and hafnium, aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium aluminate), etc. are preferably used. When the insulator 522 is formed using such a material, the insulator 522 is used as a layer that suppresses the release of oxygen from the oxide 530 or the entry of impurities such as hydrogen into the oxide 530 from the surrounding part of the transistor 500.

[0193] Alternatively, for example, aluminum oxide, bismuth oxide, germanium oxide, niobium oxide, silicon oxide, titanium oxide, tungsten oxide, yttrium oxide, or zirconium oxide may be added to the insulator. In addition, the insulator may be nitrided. Silicon oxide, silicon oxynitride, or silicon nitride may be stacked on the insulator.

[0194] The insulator 520 preferably has thermal stability. For example, silicon oxide and silicon oxynitride are preferred because they have thermal stability. In addition, by combining an insulator of a high-k material with silicon oxide or silicon oxynitride, an insulator 520 or insulator 526 having a laminated structure with thermal stability and a high relative dielectric constant can be formed.

[0195] exist Fig.9A and Fig. 9B In the transistor 500, the insulator 520, the insulator 522, and the insulator 524 are used as the second gate insulating film having a three-layer stacked structure, but the second gate insulating film may also have a stacked structure of a single layer, two layers, or four or more layers. In this case, the stacked structure is not limited to being composed of the same material, and may also be composed of different materials.

[0196] In the transistor 500, an oxide semiconductor is preferably used for the oxide 530 including the channel formation region. For example, as the oxide 530, an oxide semiconductor such as In-M-Zn oxide (the element M is selected from one or more of aluminum, gallium, yttrium, copper, vanadium, beryllium, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten and magnesium, etc.) is preferably used. In particular, the In-M-Zn oxide that can be applied to the oxide 530 is preferably CAAC-OS (c-axis aligned crystalline oxide semiconductor) or CAC-OS (Cloud-Aligned Composite oxide semiconductor). The CAAC-OS structure refers to an oxide having a CAAC structure, and the CAAC structure is a crystalline structure in which multiple IGZO nanocrystals have c-axis orientation and are connected in a non-oriented manner on the ab plane. In addition, CAC-OS refers to, for example, a structure in which the elements constituting the oxide semiconductor are unevenly distributed, wherein the size of the material containing the unevenly distributed elements is greater than 0.5nm and less than 10nm, preferably greater than 1nm and less than 2nm or a similar size. Note that in the following, a state in which one or more metal elements are unevenly distributed in an oxide semiconductor and regions containing the metal elements are mixed is referred to as a mosaic or patch shape, and the size of the region is greater than 0.5 nm and less than 10 nm, preferably greater than 1 nm and less than 2 nm or a similar size. In addition, as the oxide 530, In-Ga oxide or In-Zn oxide can also be used.

[0197] In addition, an oxide semiconductor with a low carrier concentration is preferably used as the transistor 500. In the case of reducing the carrier concentration of the oxide semiconductor, the impurity concentration in the oxide semiconductor can be reduced to reduce the defect state density. In this specification, etc., the state of low impurity concentration and low defect state density is referred to as "high-purity intrinsic" or "substantially high-purity intrinsic". Examples of impurities in the oxide semiconductor include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, silicon, etc.

[0198] In particular, hydrogen contained in an oxide semiconductor reacts with oxygen bonded to a metal atom to generate water, and thus oxygen vacancies (V O When hydrogen enters an oxygen vacancy in an oxide semiconductor, the oxygen vacancy may bond with hydrogen to form V O H.V OH is sometimes used as a donor and generates electrons as carriers. In addition, sometimes electrons as carriers are generated because part of the hydrogen is bonded to oxygen bonded to metal atoms. Therefore, transistors using oxide semiconductors containing more hydrogen tend to have normally-on characteristics. In addition, hydrogen in oxide semiconductors is easily moved by heat, electric fields, etc., so when the oxide semiconductor contains more hydrogen, the reliability of the transistor may be reduced. In one embodiment of the present invention, it is preferred to minimize the V O H and become high purity intrinsic or substantially high purity intrinsic. In order to obtain such V O To prepare an oxide semiconductor with a sufficiently low H, it is important to: remove impurities such as water and hydrogen in the oxide semiconductor (sometimes referred to as dehydration or dehydrogenation treatment); and supply oxygen to the oxide semiconductor to fill oxygen vacancies (sometimes referred to as oxidation treatment). O An oxide semiconductor in which impurities such as H are sufficiently reduced is used for a channel formation region of a transistor, and can provide stable electrical characteristics.

[0199] The defect of hydrogen entering the oxygen vacancy will be used as a donor of the oxide semiconductor. However, it is difficult to quantitatively evaluate this defect. Therefore, in oxide semiconductors, sometimes the evaluation is performed using the carrier concentration instead of the donor concentration. Therefore, in this specification, etc., as a parameter of the oxide semiconductor, sometimes the carrier concentration in a state where no electric field is applied is used instead of the donor concentration. In other words, the "carrier concentration" recorded in this specification, etc. may sometimes also be referred to as the "donor concentration".

[0200] Therefore, when an oxide semiconductor is used for the oxide 530, it is preferable to reduce the amount of hydrogen in the oxide semiconductor as much as possible. Specifically, in the oxide semiconductor, the hydrogen concentration measured by secondary ion mass spectrometry (SIMS) is less than 1×10 20 atoms / cm 3 , preferably less than 1×10 19 atoms / cm 3 , more preferably less than 5×10 18 atoms / cm 3 , and more preferably less than 1×10 18 atoms / cm 3 By using an oxide semiconductor in which impurities such as hydrogen are sufficiently reduced in a channel formation region of a transistor, the transistor can have stable electrical characteristics.

[0201] When an oxide semiconductor is used as the oxide 530, the carrier concentration of the oxide semiconductor in the channel formation region is preferably 1×10 18 cm -3less than 1×10 17 cm -3 , and more preferably less than 1×10 16 cm -3 , and further preferably less than 1×10 13 cm -3 , and further preferably less than 1×10 12 cm -3 Note that there is no particular limitation on the lower limit of the carrier concentration of the oxide semiconductor in the channel formation region, and it can be set to 1×10 -9 cm -3 .

[0202] In addition, when an oxide semiconductor is used as the oxide 530, when the conductor 542 (conductor 542a and conductor 542b) is in contact with the oxide 530, oxygen in the oxide 530 may diffuse into the conductor 542 and the conductor 542 may be oxidized. When the conductor 542 is oxidized, the conductivity of the conductor 542 is likely to decrease. In addition, "the oxygen in the oxide 530 diffuses into the conductor 542" may also be referred to as "the conductor 542 absorbs the oxygen in the oxide 530".

[0203] In addition, when oxygen in the oxide 530 diffuses into the conductor 542 (conductor 542a and conductor 542b), another layer is sometimes formed between the conductor 542a and the oxide 530b and between the conductor 542b and the oxide 530b. The other layer contains more oxygen than the conductor 542, so the other layer can be regarded as having insulating properties. At this time, the three-layer structure of the conductor 542, the other layer and the oxide 530b can be regarded as a three-layer structure composed of metal, insulator and semiconductor, sometimes called MIS (Metal-Insulator-Semiconductor, Metal-Insulator-Metal) structure or a diode junction structure with the MIS structure as the main structure.

[0204] Note that the other layer is not limited to being formed between the conductor 542 and the oxide 530b. For example, the other layer may be formed between the conductor 542 and the oxide 530c, between the conductor 542 and the oxide 530b, or between the conductor 542 and the oxide 530c.

[0205] The oxide semiconductor used as a channel formation region in the oxide 530 preferably has a band gap of 2 eV or more, preferably 2.5 eV or more. By using an oxide semiconductor with a wide band gap, the off-state current of the transistor can be reduced.

[0206] In the oxide 530, when the oxide 530a is provided below the oxide 530b, impurities can be prevented from diffusing from the structure formed below the oxide 530a to the oxide 530b. When the oxide 530c is provided above the oxide 530b, impurities can be prevented from diffusing from the structure formed above the oxide 530c to the oxide 530b.

[0207] In addition, the oxide 530 preferably has a stacked structure of oxides having different atomic number ratios of metal atoms. Specifically, the atomic number ratio of the element M in the constituent elements of the oxide semiconductor used for the oxide 530a is preferably greater than the atomic number ratio of the element M in the constituent elements of the oxide semiconductor used for the oxide 530b. In addition, the atomic number ratio of the element M relative to In in the oxide semiconductor used for the oxide 530a is preferably greater than the atomic number ratio of the element M relative to In in the oxide semiconductor used for the oxide 530b. In addition, the atomic number ratio of In relative to the element M in the oxide semiconductor used for the oxide 530b is preferably greater than the atomic number ratio of In relative to the element M in the oxide semiconductor used for the oxide 530a. In addition, the oxide 530c can use an oxide semiconductor that can be used for the oxide 530a or the oxide 530b.

[0208] It is preferable that the energy of the conduction band bottom of the oxide 530a and the oxide 530c is higher than the energy of the conduction band bottom of the oxide 530b. In other words, the electron affinity of the oxide 530a and the oxide 530c is preferably lower than the electron affinity of the oxide 530b.

[0209] Here, in the junction of oxide 530a, oxide 530b, and oxide 530c, the energy level of the conduction band bottom changes smoothly. In other words, the above situation can also be expressed as the energy level of the conduction band bottom of the junction of oxide 530a, oxide 530b, and oxide 530c continuously changes or continuously joins. For this reason, it is preferable to reduce the defect state density of the mixed layer formed at the interface between oxide 530a and oxide 530b and the interface between oxide 530b and oxide 530c.

[0210] Specifically, by making the oxide 530a and the oxide 530b, and the oxide 530b and the oxide 530c contain a common element (as a main component) in addition to oxygen, a mixed layer with a low defect state density can be formed. For example, when the oxide 530b is an In-Ga-Zn oxide, In-Ga-Zn oxide, Ga-Zn oxide, gallium oxide, etc. are preferably used as the oxide 530a and the oxide 530c.

[0211] At this time, the main path of the carrier is oxide 530b. By making oxide 530a and oxide 530c have the above structure, the defect state density at the interface between oxide 530a and oxide 530b and the interface between oxide 530b and oxide 530c can be reduced. Therefore, the influence of interface scattering on carrier conduction is reduced, and the on-state current of transistor 500 can be increased.

[0212] Conductors 542a and 542b used as source and drain electrodes are provided on the oxide 530b. As the conductors 542a and 542b, metal elements selected from aluminum, chromium, copper, silver, gold, platinum, tantalum, nickel, titanium, molybdenum, tungsten, hafnium, vanadium, niobium, manganese, magnesium, zirconium, beryllium, indium, ruthenium, iridium, strontium, and lanthanum, alloys containing the above metal elements as components, or alloys combining the above metal elements are preferably used. For example, tantalum nitride, titanium nitride, tungsten, nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxides containing strontium and ruthenium, oxides containing lanthanum and nickel, etc. are preferably used. In addition, tantalum nitride, titanium nitride, nitride containing titanium and aluminum, nitride containing tantalum and aluminum, ruthenium oxide, ruthenium nitride, oxide containing strontium and ruthenium, oxide containing lanthanum and nickel are conductive materials that are not easily oxidized or materials that maintain conductivity even when absorbing oxygen, so they are preferred. Furthermore, metal nitride films such as tantalum nitride have barrier properties against hydrogen or oxygen, so they are preferred.

[0213] In addition, although the conductor 542a and the conductor 542b of a single-layer structure are shown in FIG9 , a stacked structure of two or more layers may be adopted. For example, it is preferable to stack a tantalum nitride film and a tungsten film. Alternatively, a titanium film and an aluminum film may be stacked. Alternatively, a two-layer structure of stacking an aluminum film on a tungsten film, a two-layer structure of stacking a copper film on a copper-magnesium-aluminum alloy film, a two-layer structure of stacking a copper film on a titanium film, or a two-layer structure of stacking a copper film on a tungsten film may be adopted.

[0214] Alternatively, a three-layer structure may be used in which an aluminum film or a copper film is stacked on a titanium film or a titanium nitride film and a titanium film or a titanium nitride film is formed thereon, or an aluminum film or a copper film is stacked on a molybdenum film or a molybdenum nitride film and a molybdenum film or a molybdenum nitride film is formed thereon. Alternatively, a transparent conductive material containing indium oxide, tin oxide, or zinc oxide may be used.

[0215] In addition, if Fig.9A As shown, sometimes, a region 543a and a region 543b are formed as a low resistance region at the interface between the oxide 530 and the conductor 542a (conductor 542b) and in the vicinity thereof. In this case, the region 543a is used as one of the source region and the drain region, and the region 543b is used as the other of the source region and the drain region. In addition, a channel formation region is formed in a region sandwiched between the region 543a and the region 543b.

[0216] The oxygen concentration of the region 543a (region 543b) may be reduced by forming the above-mentioned conductor 542a (conductor 542b) in contact with the oxide 530. In addition, a metal compound layer including a metal contained in the conductor 542a (conductor 542b) and a component of the oxide 530 may be formed in the region 543a (region 543b). In this case, the carrier concentration of the region 543a (region 543b) increases, and the region 543a (region 543b) becomes a low resistance region.

[0217] The insulator 544 is provided so as to cover the conductors 542 a and 542 b and suppress oxidation of the conductors 542 a and 542 b. In this case, the insulator 544 may be provided so as to cover the side surface of the oxide 530 and to be in contact with the insulator 524.

[0218] As the insulator 544, an oxide semiconductor including one or more selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, neodymium, lanthanum, and magnesium can be used. Alternatively, as the insulator 544, silicon nitride oxide or silicon nitride can be used.

[0219] In particular, as the insulator 544, aluminum oxide, hafnium oxide, an oxide containing aluminum and hafnium (hafnium aluminate), etc., which are insulators containing oxides of one or both of aluminum and hafnium, are preferably used. In particular, hafnium aluminate has higher heat resistance than hafnium oxide. Therefore, it is not easy to crystallize in the heat treatment of the subsequent process, so it is preferred. In addition, when the conductor 542a and the conductor 542b are materials with oxidation resistance or their conductivity does not significantly decrease even if oxygen is absorbed, it is not necessary to provide the insulator 544. It can be designed appropriately according to the required transistor characteristics.

[0220] By including the insulator 544, impurities such as water and hydrogen contained in the insulator 580 can be prevented from diffusing into the oxide 530b through the oxide 530c and the insulator 550. In addition, oxidation of the conductor 560 by excess oxygen contained in the insulator 580 can be prevented.

[0221] The insulator 550 is used as a first gate insulating film. The insulator 550 is preferably arranged in contact with the inner side (top surface and side surface) of the oxide 530c. As with the insulator 524 described above, the insulator 550 is preferably formed using an insulator containing excess oxygen and releasing oxygen by heating.

[0222] Specifically, silicon oxide containing excess oxygen, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide added with fluorine, silicon oxide added with carbon, silicon oxide added with carbon and nitrogen, and silicon oxide having pores can be used. In particular, silicon oxide and silicon oxynitride are preferred because they have thermal stability.

[0223] By providing an insulator that releases oxygen by heating so as to be in contact with the top surface of the oxide 530c as the insulator 550, oxygen can be effectively supplied from the insulator 550 to the channel formation region of the oxide 530b through the oxide 530c. In addition, as with the insulator 524, it is preferable to reduce the concentration of impurities such as water and hydrogen in the insulator 550. The thickness of the insulator 550 is preferably not less than 1 nm and not more than 20 nm.

[0224] In order to efficiently supply the excess oxygen contained in the insulator 550 to the oxide 530, a metal oxide may be provided between the insulator 550 and the conductor 560. The metal oxide preferably suppresses the diffusion of oxygen from the insulator 550 to the conductor 560. By providing a metal oxide that suppresses the diffusion of oxygen, the diffusion of excess oxygen from the insulator 550 to the conductor 560 is suppressed. In other words, the reduction of excess oxygen supplied to the oxide 530 can be suppressed. In addition, the 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 can be used.

[0225] In addition, similar to the second gate insulating film, the insulator 550 may also have a stacked structure. When miniaturization and high integration of transistors are performed, problems such as leakage current may occur due to the thin film of the gate insulating film. Therefore, by making the insulator used as the gate insulating film have a stacked structure of a high-k material and a thermally stable material, the gate potential during operation of the transistor can be reduced while maintaining the physical thickness. In addition, a stacked structure with thermal stability and a high relative dielectric constant can be realized.

[0226] exist Fig.9A and Fig. 9B In the embodiment, the conductor 560 used as the first gate electrode has a two-layer structure, but may have a single-layer structure or a stacked-layer structure of three or more layers.

[0227] As the conductor 560a, it is preferred to use a conductive material having the function of inhibiting the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, nitrogen oxide molecules (N2O, NO, NO2, etc.), copper atoms, etc. In addition, it is preferred to use a conductive material having the function of inhibiting the diffusion of oxygen (for example, at least one of oxygen atoms, oxygen molecules, etc.). By making the conductor 560a have the function of inhibiting the diffusion of oxygen, it is possible to inhibit the oxidation of the conductor 560b due to the oxygen contained in the insulator 550 and the decrease in conductivity. As a conductive material having the function of inhibiting the diffusion of oxygen, for example, tantalum, tantalum nitride, ruthenium or ruthenium oxide, etc. are preferably used. In addition, as the conductor 560a, an oxide semiconductor that can be applied to the oxide 530 can be used. At this time, by forming the conductor 560b using a sputtering method, the resistance value of the conductor 560a can be reduced to make it a conductor. The conductor can be called an OC (Oxide Conductor) electrode.

[0228] In addition, as the conductor 560b, it is preferable to use a conductive material with tungsten, copper or aluminum as a main component. Since the conductor 560b is also used as wiring, it is preferable to use a conductor with high conductivity. For example, a conductive material with tungsten, copper or aluminum as a main component can be used. In addition, the conductor 560b can also have a laminated structure, for example, a laminated structure of titanium or titanium nitride and the above conductive materials can be used.

[0229] The insulator 580 is preferably disposed on the conductor 542a and the conductor 542b via the insulator 544. The insulator 580 preferably has an excess oxygen region. For example, the insulator 580 preferably includes silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, silicon oxide added with fluorine, silicon oxide added with carbon, silicon oxide added with carbon and nitrogen, silicon oxide with pores, or resin. In particular, silicon oxide and silicon oxynitride are thermally stable and therefore are preferred. In particular, silicon oxide and silicon oxide with pores are preferred because they are easy to form an excess oxygen region in the subsequent process.

[0230] The insulator 580 preferably has an excess oxygen region. By providing the insulator 580 that releases oxygen by heating in contact with the oxide 530c, the oxygen in the insulator 580 can be efficiently supplied to the oxide 530 through the oxide 530c. In addition, the concentration of impurities such as water and hydrogen in the insulator 580 is preferably reduced.

[0231] The opening of the insulator 580 is formed so as to overlap with the region between the conductor 542a and the conductor 542b. Thus, the conductor 560 is embedded in the opening of the insulator 580 and in the region between the conductor 542a and the conductor 542b.

[0232] When miniaturizing semiconductor devices, it is necessary to shorten the gate length, but it is necessary to prevent the conductivity of the conductor 560 from decreasing. For this reason, when the thickness of the conductor 560 is increased, the conductor 560 may have a shape with a high aspect ratio. In this embodiment, since the conductor 560 is buried in the opening of the insulator 580, even if the conductor 560 has a shape with a high aspect ratio, the conductor 560 does not collapse during the process.

[0233] 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 sputtering, an excess oxygen region can be formed in the insulator 550 and the insulator 580. Thus, oxygen can be supplied to the oxide 530 from the excess oxygen region.

[0234] For example, as the insulator 574, an oxide semiconductor including one or two or more selected from hafnium, aluminum, gallium, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium, and magnesium can be used.

[0235] In particular, aluminum oxide has high barrier properties and can inhibit the diffusion of hydrogen and nitrogen even in a thin film of 0.5 nm to 3.0 nm. Therefore, aluminum oxide formed by sputtering can be used as an oxygen supply source while also functioning as a barrier film for impurities such as hydrogen.

[0236] In addition, after forming the transistor 500, an opening may be formed in a manner surrounding the transistor 500, and an insulator having a high barrier property to hydrogen or water may be formed in a manner surrounding the opening. By surrounding the transistor 500 with the above-mentioned insulator having a high barrier property, water and hydrogen may be prevented from intruding from the outside. Alternatively, a plurality of transistors 500 may be combined into one and surrounded by an insulator having a high barrier property to hydrogen or water. When forming the opening in a manner surrounding the transistor 500, since it can also serve as a part of the manufacturing process of the transistor 500, it is preferable to form an opening that reaches the insulator 514 or the insulator 522 and form the above-mentioned insulator having a high barrier property in a manner in contact with the insulator 514 or the insulator 522. As the insulator having a high barrier property to hydrogen or water, for example, the same material as the insulator 522 may be used.

[0237] In addition, an insulator 581 used as an interlayer film is preferably provided over the insulator 574. As with the insulator 524 and the like, the concentration of impurities such as water and hydrogen in the insulator 581 is preferably reduced.

[0238] In addition, conductors 540a and 540b are arranged in openings formed in insulators 581, 574, 580, and 544. Conductors 540a and 540b are arranged to face each other via conductor 560. Conductors 540a and 540b have the same structure as conductors 546 and 548 described later.

[0239] An insulator 582 is provided on the insulator 581. A substance having a barrier property against oxygen or hydrogen is preferably used for the insulator 582. Therefore, the insulator 582 can be made of the same material as the insulator 514. For example, the insulator 582 is preferably made of a metal oxide such as aluminum oxide, hafnium oxide, or tantalum oxide.

[0240] In particular, aluminum oxide has a high barrier effect of preventing oxygen and impurities such as hydrogen and moisture that cause changes in the electrical characteristics of the transistor from penetrating. Therefore, during and after the manufacturing process of the transistor, aluminum oxide can prevent impurities such as hydrogen and moisture from entering the transistor 500. In addition, aluminum oxide can suppress the release of oxygen from the oxide constituting the transistor 500. Therefore, aluminum oxide is suitable for use as a protective film for the transistor 500.

[0241] Insulator 586 is provided on insulator 582. The same material as insulator 320 can be used as insulator 586. In addition, by using a material with a low dielectric constant for the insulator, parasitic capacitance generated between wirings can be reduced. For example, silicon oxide film, silicon oxynitride film, etc. can be used as insulator 586.

[0242] In addition, the conductor 546 and the conductor 548 are buried in 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 .

[0243] The conductor 546 and the conductor 548 are used as plugs or wirings connected to the capacitor 600, the transistor 500, or the transistor 300. The conductor 546 and the conductor 548 can be formed using the same material as the conductor 328 and the conductor 330.

[0244] Next, a capacitor 600 is disposed above the transistor 500 . The capacitor 600 includes a conductor 610 , a conductor 620 , and an insulator 630 .

[0245] In addition, a conductor 612 may be provided over the conductor 546 and the conductor 548. The conductor 612 is used as a plug or wiring connected to the transistor 500. The conductor 610 is used as an electrode of the capacitor 600. In addition, the conductor 612 and the conductor 610 may be formed at the same time.

[0246] As the conductor 612 and the conductor 610, a metal film containing an element selected from molybdenum, titanium, tantalum, tungsten, aluminum, copper, chromium, neodymium, and scandium, or a metal nitride film containing the above elements as a component (tantalum nitride film, titanium nitride film, molybdenum nitride film, tungsten nitride film), etc. can be used. Alternatively, a conductive material such as indium tin oxide, indium oxide containing tungsten oxide, indium zinc oxide containing tungsten oxide, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, indium zinc oxide, indium tin oxide added with silicon oxide, etc. can also be used.

[0247] exist Figure 7 In the embodiment, the conductor 612 and the conductor 610 have a single-layer structure, but the present invention is not limited thereto and they may have a stacked structure of two or more layers. For example, a conductor having high compactness with the conductor having barrier properties and the conductor having high conductivity may be formed between the conductor having barrier properties and the conductor having high conductivity.

[0248] The conductor 620 is provided so as to overlap the conductor 610 via the insulator 630. Conductive materials such as metal materials, alloy materials, and metal oxide materials can be used as 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 tungsten is particularly preferable. In addition, when the conductor 620 is formed simultaneously with other components such as a conductor, low-resistance metal materials such as Cu (copper) or Al (aluminum) can be used.

[0249] An insulator 640 is provided on the conductor 620 and the insulator 630. The insulator 640 can be formed using the same material as the insulator 320. In addition, the insulator 640 can be used as a planarization film that covers the concavo-convex shape thereunder.

[0250] By adopting this structure, miniaturization or high integration of a semiconductor device using a transistor including an oxide semiconductor can be achieved.

[0251] (Implementation 5)

[0252] In this embodiment, in addition to the heating device 132 and the cooling device 131, Fig.10 An example in which an alarm is sounded to warn the user is also shown. Fig.10 is a block diagram, only part of which is related to Figure 1 The description of the same parts is omitted here.

[0253] In an electric vehicle, if the temperature of a secondary battery rises or falls and exceeds a temperature range in which normal operation can be performed, a warning sound is emitted to notify the user of an impending danger of an EV system abnormality. The warning sound can be emitted by an audio control device 151 of an audio device 150 through a speaker device 152 in response to a signal from an abnormality detection system 110.

[0254] Furthermore, when the temperature of the secondary battery rises or falls and exceeds a temperature range in which normal operation is possible, a warning sound may be emitted to notify the user of the danger of an impending EV system abnormality.

[0255] In addition, the warning is not limited to the warning by audio, and the audio device 150 may use any one of the warnings by vibration and the warning by light emission, or a combination of the above warning methods.

[0256] This embodiment mode can be freely combined with other embodiment modes.

[0257] (Implementation 6)

[0258] Figure 5 A block diagram showing the entire abnormality detection system for a secondary battery (hereinafter referred to as a battery) that performs temperature control.

[0259] exist Figure 5 In the figure, vehicle 140 is other parts of the electric vehicle and includes a control circuit other than the charging control circuit, an air conditioning device, and the like.

[0260] The abnormality detection system 110 at least includes a charging control circuit and a storage unit.

[0261] The temperature of the first battery 121 is measured by the temperature sensor 122 and managed by the abnormality detection system 110. During charging, if the temperature rises and exceeds the allowable range, the audio device 150 is activated to warn the user, and a control signal is input from the abnormality detection system 110 to the current interruption switch 123 to stop charging.

[0262] like Figure 4A As shown, a cooling device 131 and a heating device 132 are provided adjacent to the first battery 121. The cooling device 131 and the heating device 132 may be referred to as a temperature control device 130 for the first battery 121. In addition, if the temperature increases and exceeds the allowable range, a command signal is input from the abnormality detection system 110 to the cooling device 131 to reduce the temperature of the first battery 121. In addition, if the temperature decreases and falls below the allowable range, a command signal is input from the abnormality detection system 110 to the heating device 132 to increase the temperature of the first battery 121. The temperature control device 130 for the secondary battery includes the cooling device 131 and the heating device 132.

[0263] Note that, specifically, the abnormality detection system 110 shows an aggregate of a plurality of ICs (CPUs, etc.) and the like provided on a printed circuit board or the like.

[0264] The abnormality detection system 110 performs temperature management of the battery through analog signal processing or digital signal processing.

[0265] When using analog signals to detect temperature, such as Figure 2A As shown, the temperature detection 111 can detect the temperature state of the battery by using the output signal (temperature information) of the temperature sensor as an analog signal.

[0266] When using digital signals to detect temperature, such as Figure 2B As shown, the ADC 113 converts the battery temperature (analog signal) into a digital signal and outputs the digital signal.

[0267] The temperature detection 111 can be performed by Figure 3 A hysteresis comparator such as that shown generates a pulse signal for on and off control.

[0268] Furthermore, a case where the abnormality detection system is applied to a car will be described using FIG. 4 which is a block diagram shown in Embodiment 1. FIG. Figure 4A Although the temperature control device 130 is shown, a configuration may be adopted in which no temperature adjustment mechanism is provided for the first battery 121 and only an alarm is output from the speaker device 152 when the temperature exceeds a temperature range.

[0269] The operation of the audio device 150 that emits the warning sound is as follows: When the potential corresponding to the battery temperature is lower than the low temperature setting (low), the warning control signal (low temperature) output by the hysteresis comparator is turned on. For example, when a pulse signal that is turned on at a certain interval is input, the volume of the warning sound is adjusted according to the cycle. The volume becomes louder when the cycle is short, and the volume becomes smaller when the cycle is long. When the potential corresponding to the battery temperature exceeds the low temperature setting (high), the warning control signal (low temperature) output by the hysteresis comparator is turned off, and the audio device 150 stops emitting the warning sound.

[0270] The audio device 150 may also be a system structure using the car horn of an electric car. In addition, in order to appeal to human senses, in addition to the sound output (auditory stimulation), the light output (visual stimulation) using the light emitting element (headlight, etc.) of the electric car may also be incorporated into the system.

[0271] The battery abnormality detection system disclosed in this specification detects abnormal temperature of a secondary battery and issues a warning to the user, thereby avoiding a serious situation.

[0272] This embodiment mode can be implemented in combination with the configurations described in other embodiment modes as appropriate.

[0273] [Explanation of symbols]

[0274] 110: Abnormality detection system, 111: Temperature detection, 112: Protection circuit, 113: ADC, 114: Temperature detection operation circuit, 120: Battery module, 121: Battery, 122: Temperature sensor, 123: Current interruption switch, 130: Temperature control device, 131: Cooling device, 132: Heating device, 140: Vehicle, 150: Audio device, 151: Audio control device, 152: Speaker device, 202: Battery controller, 203: Engine controller, 204: Engine, 205: Transmission, 206: DCDC circuit, 210: DCDC circuit, 211: Battery, 212: Inverter, 216: Tire, 300: Transistor, 311: Substrate, 3 13: 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: insulator, 354: insulator, 356: conductor, 360: insulator, 362: insulator, 364: insulator, 366: conductor, 370: insulator, 372: insulator, 374: insulator, 376: conductor, 380: insulator, 382: insulator, 384: insulator, 386: conductor, 410: storage element, 420: storage element, 430: storage 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 Insulator, 546: Conductor, 548: Conductor, 550: Insulator, 560: Conductor, 560a: Conductor, 560b: Conductor, 574: Insulator, 580: Insulator, 581: Insulator, 582: Insulator, 586: Insulator, 600: Capacitor, 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, 613: Conductive plate, 614: Conductive plate, 616: Secondary battery, 617: Safety valve mechanism, 620: Conductor, 630: Insulator,640: insulator, 1400: storage battery, 1402: positive electrode, 1404: negative electrode, 1406: electrolyte, 1408: separator, 8021: charging device, 8022: cable, 8024: secondary battery, 8400: automobile, 8401: headlight, 8406: electric engine, 8500: automobile, 8600: small motorcycle, 8601: rearview mirror, 8602: secondary battery, 8603: turn signal, 8604: under-seat storage box.

Claims

1. A charging control circuit for a secondary battery, comprising: a temperature sensor for detecting the temperature of the secondary battery; a first temperature comparison circuit and a second temperature comparison circuit which receive an analog signal from the temperature sensor and generate a pulse signal; a heating device for the secondary battery operating within two temperature ranges set using the first temperature comparison circuit; a cooling device for the secondary battery operating within two temperature ranges set using the second temperature comparison circuit; as well as A storage unit configured to hold an analog signal, The memory cell includes a transistor using an oxide semiconductor as a semiconductor layer, a capacitor, a first wiring, a second wiring, and a third wiring. The transistor includes a first gate and a second gate, A first terminal of the transistor is electrically connected to the first wiring, The second terminal of the transistor is electrically connected to the first terminal of the capacitor, The first gate of the transistor is electrically connected to the second wiring, The second gate of the transistor is electrically connected to the third wiring.

2. The charging control circuit for a secondary battery according to claim 1, The first temperature comparison circuit includes a comparator with two thresholds.

3. The charging control circuit for a secondary battery according to claim 1, The charging control circuit of the secondary battery controls the opening and closing of a switch for interrupting the charging current of the secondary battery.

4. A charging control circuit for a secondary battery, comprising: a temperature sensor for detecting the temperature of the secondary battery; a temperature comparison circuit which receives an analog signal from the temperature sensor and generates a pulse signal; An audio device that operates within a temperature range set using the temperature comparison circuit; as well as A storage unit configured to hold an analog signal, Wherein, the temperature comparison circuit includes a comparator with two thresholds, The memory cell includes a transistor using an oxide semiconductor as a semiconductor layer, a capacitor, a first wiring, a second wiring, and a third wiring. The transistor includes a first gate and a second gate, A first terminal of the transistor is electrically connected to the first wiring, The second terminal of the transistor is electrically connected to the first terminal of the capacitor, The first gate of the transistor is electrically connected to the second wiring, The second gate of the transistor is electrically connected to the third wiring.

5. The charging control circuit for a secondary battery according to claim 1 or 4, The charging control circuit of the secondary battery is arranged on a printed circuit board.

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