Battery packs and electronic devices

Abstract

It incorporates a circuit that safely controls the operation of the secondary battery, while also saving space by miniaturizing the casing. To achieve a configuration that can accommodate systemization. [Solution] A charging control circuit is provided on a flexible substrate and attached to the outer surface of the secondary battery. At least one of the two terminals on the battery is electrically connected to the charging control circuit, and the charging control is performed. To prevent overcharging, both the output transistor and the cutoff switch of the charging circuit are set to be approximately the same. It is sometimes switched off. Overcharging is detected by interrupting the two paths connected to the battery. In such cases, charging can be stopped quickly, reducing damage to the battery caused by overcharging.

Description

Technical Field

[0001] One aspect of the present invention relates to an object, a method, or a manufacturing method. Alternatively, the present invention relates to a process, a machine, a manufacture, or a composition of matter. One aspect 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 manufacturing method thereof. In particular, it relates to a semiconductor device using an oxide semiconductor and a method for manufacturing the same.

[0002] In this specification, the semiconductor device refers to all devices that can function by utilizing semiconductor characteristics, and electro-optical devices, semiconductor circuits, and electronic devices are all semiconductor devices. <00000​​​​​​​​​​​​​​​​​​​​​​​​​​​​It is used in cameras and other devices. Lithium-ion rechargeable batteries are also used in other applications, such as medical equipment. Vehicle, or hybrid electric vehicle (HEV), electric vehicle (EV), or plug-in hybrid Next-generation clean energy vehicles such as plug-in hybrid electric vehicles (PHEVs), electric motorcycles, and electric assist systems. It is also used in electric vehicles such as bicycles. Thus, lithium-ion rechargeable batteries. The demand for these batteries has expanded rapidly alongside the development of the semiconductor industry, and they are a source of rechargeable energy. It has become indispensable in today's information society.

[0006] Rechargeable batteries are repeatedly recharged as the user uses them and the remaining charge decreases. Since repeated charging degrades the secondary battery, the charging conditions should be changed according to the degree of degradation of the secondary battery. Measures are being taken to extend the lifespan of secondary batteries. Secondary batteries are manufactured immediately after production. There are individual differences, and the battery deteriorates with the number of cycles, further influenced by battery voltage, charge / discharge current, and temperature. It is affected by various parameters such as internal resistance.

[0007] Furthermore, lithium-ion rechargeable batteries can overheat due to internal short circuits or overcharging as they degrade. It is known to malfunction. Detect warning signs of abnormalities before thermal runaway occurs and take safety measures. It is hoped that this will happen.

[0008] In mobile devices and electric vehicles, multiple secondary batteries are connected in series or in parallel. A protective circuit is provided, and it is used as a battery pack (also called a battery assembly). A battery pack is, To facilitate the handling of rechargeable batteries, a battery module consisting of multiple rechargeable batteries is used. This refers to a device that, along with a predetermined circuit, is housed inside a container (metal can, film casing).

[0009] Furthermore, there is no problem if all the secondary batteries that make up the battery pack are functioning normally, but if even one is different If this continues, it will negatively affect other rechargeable batteries, and if the protection circuit activates, the battery pack will be shut down. Yes.

[0010] Furthermore, in the case of mobile information terminals, progress is being made in making the casing smaller or thinner, The desired features of the information terminal are a small casing and a large rechargeable battery capacity, and the space within the casing is There are limits.

[0011] Conventionally, to ensure safety in the event of a malfunction in a secondary battery, a protection circuit was used to prevent overcharging and over-discharging. It is mounted on a rigid circuit board (printed wiring board) as an IC chip. Also, the discharge current Switching circuits for conducting and interrupting current are mounted on IC chips, and these multiple ICs The chips are assembled and mounted on a rigid substrate. Additionally, the protection circuit IC chip and... A small rigid board with both IC chips of the switching circuit mounted on it connects to the two terminals of the battery cell. One is a rigid substrate and battery cell that are placed in between and fixed together with a film. It may form a battery pack.

[0012] Patent Document 1 describes a battery state detection device for detecting minute short circuits in secondary batteries and a battery incorporating the same. The pond pack is shown.

[0013] Furthermore, regarding oxide semiconductors (also known as oxide semiconductors), For example, not only oxides of monochemical metals such as indium oxide and zinc oxide, but also oxides of multichemical metals Oxides are also known. Among the oxides of multi-component metals, in particular, In-Ga-Zn oxide ( Research on IGZO (also known as IGZO) is being actively conducted.

[0014] Research on IGZO has shown that in oxide semiconductors, CA is neither single crystal nor amorphous. AC (c-axis aligned crystalline) structure, and nc( (Non-Patent Documents 1 to 3) A nanocrystalline structure was discovered (Non-Patent Documents 1 to 3). reference).

[0015] Non-Patent Documents 1 and 2 describe using an oxide semiconductor having a CAAC structure, A technique for fabricating lungers has been disclosed. Furthermore, from CAAC structure and nc structure Even oxide semiconductors with low crystallinity can have minute crystals, as shown in Non-Patent Document 4 and This is shown in Non-Patent Document 5.

[0016] Non-patent document 6 states that the off-current of a transistor using an oxide semiconductor is very small. It has been reported that the property of having a very small off-current is utilized in Non-Patent Documents 7 and 8. LSI (Large Scale Integration) and display This has been reported. [Prior art documents] [Patent Documents]

[0017] [Patent Document 1] Japanese Patent Publication No. 2010-66161 [Non-patent literature]

[0018] [Non-Patent Document 1] S. Yamazaki et al., “SID Symposium Digest of Technical Papers”, 2012, volume 43, issue 1, p.183-186 [Non-Patent Document 2] S. Yamazaki et al., “Japanese Journal of Applied Physics”, 2014, volume 53, Number 4S, p.04ED18-1-04ED18-10 [Non-Patent Document 3] S. Ito et al., “The Proceedings of AM-FPD'13 Digest of Technical Papers”, 2013, p.151-154 [Non-Patent Document 4] S. Yamazaki et al., “ECS Journal of Solid State Science and Technology”, 2014, volume 3, issue 9, p. Q3012-Q3022 [Non-Patent Document 5] S.Yamazaki,“ECS Transactions”,2014,volume 64,issue 10,p.155-164 [Non-Patent Document 6] K. Kato et al., “Japanese Journal of Applied Physics”, 2012, volume 51, p.021201-1-021201-7 [Non-Patent Document 7] S. Matsuda et al., “2015 Symposium on VLSI Technology Digest of Technical Papers”, 2015, p.T216-T217 [Non-Patent Document 8] S. Amano et al., “SID Symposium Digest of Technical Papers”, 2010, volume 41, issue 1, p.626-629 [Overview of the project] [Problems that the invention aims to solve]

[0019] To simplify the recharge process of secondary batteries, a wireless connection is used between the power supply device (charger) and the portable information terminal. Wireless power transfer (also known as wireless charging), which utilizes power transmission via wires, is becoming increasingly widespread. .

[0020] The transmitting wireless power supply is a power supply device (charger), and the receiving wireless power supply is a mobile information terminal. When the power source is brought spatially closer, the energy from the alternating magnetic flux generated by the charger is transferred to the receiving power source. It is transmitted to the coil. AC current is generated from the receiving coil and sent to the rectifier circuit to convert it into DC current. It is converted. The receiving wireless power supply has at least a receiving coil and a rectifier circuit. The receiving wireless power supply converts the current and voltage required for the secondary battery to charge. It has a charging circuit, such as a current-voltage conversion circuit.

[0021] Even with wireless charging, to ensure safety during charging, an abnormality in the secondary battery is detected, for example, two The system detects phenomena that reduce the safety of secondary batteries at an early stage and warns the user, or the secondary battery's safety. One of the challenges is ensuring safety by suspending [the system / service].

[0022] Furthermore, it incorporates a circuit to safely control the operation of the secondary battery, while also saving space by miniaturizing the casing. One of the challenges is to create a configuration that can handle the transition to a new system.

[0023] Furthermore, since the lifespan of a rechargeable battery tends to shorten with an increase in the number of charging cycles, To reduce this, it is preferable to lengthen the interval between charging times. Especially when not in use Power saving in standby mode, such as turning off the screen, is a good approach. Also, some circuits receive power when the power switch is turned on, so such circuits It is also desirable to control power consumption. Therefore, reducing the number of charging cycles and extending the lifespan of the rechargeable battery is desirable. Making them last longer is also a challenge. Furthermore, this applies not only to secondary batteries but also to primary batteries. One of the challenges is to increase the interval between replacements. [Means for solving the problem]

[0024] To solve the above problem, a charging control circuit is provided on a flexible substrate and attached to the outer surface of the battery. At least one of the two terminals on the battery is electrically connected to the charging control circuit, and the charging control To perform the operation. When wireless charging is performed, the charging control circuit also performs the charging circuit (current-voltage conversion). Electrical circuits, rectifier circuits, and receiving coils (also called antennas or secondary coils) It connects to the network.

[0025] To prevent overcharging of the battery, when overcharging is detected, the charging control circuit connects the positive and negative terminals of the battery. The circuit breaker switches located in two places on the eggplant side are controlled to the OFF state. In this way, the electricity By cutting off the power supply to the pond at two points, the secondary battery can be protected from overcharging.

[0026] One configuration of the invention disclosed herein is a secondary battery and connected to a first terminal of the secondary battery A first transmission line that transmits the power output from the secondary battery during discharge, and connected to the first transmission line. The charging control circuit is provided on a flexible substrate in contact with the side surface of the secondary battery, and the charging control circuit A second transmission path connects the second terminal of the secondary battery to the second terminal of the secondary battery, and a first channel blocks the second transmission path. A switch, a charging circuit electrically connected to a charging control circuit, and a charging circuit electrically connected to the charging circuit A power receiving circuit, an antenna electrically connected to the power receiving circuit, and a charging circuit that receives power from the power receiving circuit during charging. A third transmission path through which power is supplied to the secondary battery, and a charging circuit that disconnects the third transmission path. The circuit has a second switch which is an output transistor, and the first switch is connected to the secondary battery. In the event of overcharging, the second transmission path is interrupted, and the charging control circuit detects an abnormality during secondary battery charging. If this occurs, the second transmission path is interrupted to stop charging, and the second switch is activated to stop overcharging to the secondary battery. During charging, the third transmission path is interrupted, and the charging circuit notifies the power receiving circuit of the completion of charging. It is a stem.

[0027] Charging lithium-ion secondary batteries using an antenna (secondary coil) is done according to the Qi standard. It employs wireless charging and can perform contactless charging using a charger with a primary coil. The devices disclosed herein are wireless charging devices with signal communication capabilities according to the Qi standard. This is an electronic device having a joule, and this new electronic device receives a signal from an external charger Q It can be received by a wireless charging module that has signal communication functionality based on the i standard.

[0028] The charging control circuit, located on a flexible substrate, detects overcharging and activates a first switch and a second switch. It outputs a signal that turns the switch to the OFF state, and stops the power supply from the primary coil. Because it can stop power transmission, wireless charging prevents over-discharge compared to wired charging. It is possible.

[0029] Because power consumption can be reduced, the above charging control circuit uses an oxide semiconductor. It is preferable to use a transistor. Transistors that use an oxide semiconductor in the semiconductor layer are The leakage current in the fused state is very small. Transistors using oxide semiconductors have a channel Off-current normalized by width: several yA (yoctoamperes) / μm or more, several zA (zeptamperes) a) It can be reduced to approximately 1 / μm or less.

[0030] Furthermore, because it can be used in high-temperature environments, the charging control circuit uses an oxide semiconductor transient It is preferable to use a sta. To simplify the process, the charging control circuit is unipolar. It may also be formed using a transistor. Transistor using an oxide semiconductor for the semiconductor layer The operating ambient temperature range is wider than that of single-crystal Si, from -40°C to 150°C, and the secondary battery is The change in properties when heated is smaller compared to single crystals. (Regarding the off-state of transistors using oxide semiconductors) The current is below the detection limit regardless of temperature, even at 150°C, but single crystal Si transistors The off-current characteristics of the transistor are highly temperature-dependent. For example, at 150°C, the single-crystal Si transistor... The off-current increases, and the current on / off ratio does not become sufficiently large.

[0031] A charging control circuit having a memory circuit including an oxide semiconductor transistor, or a battery-powered Your system is called BTOS (Battery operating system). It may happen.

[0032] In the case of a cylindrical rechargeable battery, the flexible substrate is bent and wrapped around the curved surface of the side of the rechargeable battery. It can also be installed.

[0033] Furthermore, a protection circuit, a first switch, and the charging control circuit are provided on the same flexible substrate. This enables a configuration that can accommodate space savings due to the miniaturization of the enclosure.

[0034] Flexible substrates can be made of organic resin film or metal film. Examples of materials for the material include polyester resins such as PET and PEN, and polyacrylonnitrile. Acrylic resin, polyimide resin, polymethyl methacrylate resin, PC resin, P ES resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin Fin resin, polystyrene resin, polyamide-imide resin, polyurethane resin, polychlorinated vinyl Polyvinylidene resin, polyvinylidene chloride resin, polypropylene resin, PTFE resin, ABS resin, etc. These are some examples.

[0035] Stainless steel, aluminum, and other materials can be used as the metal film.

[0036] A method for forming a charging control circuit on a flexible substrate involves forming it on a semiconductor substrate and then removing it. A method is used in which the material is removed and then fixed onto a flexible substrate. In the removal method, a known method is used. The technology can be used. Also, after forming it on a semiconductor substrate and polishing the back surface, it becomes flexible. It may also be a method of fixing it on a substrate. Alternatively, it may be a method of partially cutting it out using a laser beam. Alternatively, the laser-cut components may be fixed onto a flexible substrate. Alternatively, the charging control circuit formed on the glass substrate may be peeled off. A method is used in which the material is removed using a detachment method and then fixed onto a flexible substrate.

[0037] In this specification, the term "charging control circuit" refers to the control of the charging voltage and charging current, and the degree of degradation. This refers to a circuit that performs one or all of the following: controlled charging current, micro-short detection. They are doing it.

[0038] A microshort refers to a tiny short circuit inside a rechargeable battery, which affects the positive terminal of the rechargeable battery. It's not to the point where the polarity and negative electrode are short-circuited to the point of being unable to charge or discharge, but rather a very small short circuit. This refers to the phenomenon where a short-circuit current flows. It occurs for a relatively short time and in a small area. Even a small voltage change can occur, and that abnormal voltage value could affect subsequent estimations. There is.

[0039] Due to the uneven distribution of the positive electrode active material after multiple charge-discharge cycles, a portion of the positive electrode and A localized current concentration occurs in a part of the negative electrode, causing a section of the separator to malfunction. Alternatively, a phenomenon called microshort occurs due to the generation of by-reactants from side reactions. It is said that...

[0040] In addition to detecting micro-shorts, the charging control circuit also detects the terminal voltage of the secondary battery. It manages the charging and discharging state of the secondary battery. For example, to prevent overcharging, it uses an output transistor on the charging circuit. Both the inverter and the cutoff switch can be turned off almost simultaneously.

[0041] One of the configurations of other inventions disclosed herein is a secondary battery and a connection to a first terminal of the secondary battery. Furthermore, a first transmission path is provided for transmitting the power output from the secondary battery during discharge, and the first transmission path is connected to the first transmission path. A charging control circuit is connected and provided on a flexible substrate in contact with the side of the secondary battery, and a charging control A second transmission path connects the circuit to the second terminal of the secondary battery, and a blockage that interrupts the second transmission path. It has a switch, a charging control circuit, and a charging circuit electrically connected to the charging control circuit, and the charging control circuit is It is a semiconductor device that controls both the cutoff switch and the output transistor of the charging circuit.

[0042] The first switch that interrupts the second transmission path is a switch for controlling conduction and interruption operations. It is a switch, and can also be called a protection circuit. Furthermore, this first switch is combined with a diode. This can also be used to configure a protection circuit. Such a protection circuit and the charging control circuit mentioned above It can be said that it is protected by a double layer of protection, making it a highly safe semiconductor device.

[0043] The first switch (also called a cutoff switch) is formed using a transistor made of an oxide semiconductor. It is also possible.

[0044] Furthermore, to prevent overcharging, the output transistor of the charging circuit, which blocks the third transmission path, Switch 2 can also be formed using a transistor made of oxide semiconductor.

[0045] In this specification, a protection circuit is defined as a circuit that prevents overcharging, overcurrent, or overdischarge. It refers to a circuit that performs one or all of the following actions. It also refers to a circuit used to interrupt charging. Switches are sometimes included in the protection circuit.

[0046] The flexible substrate equipped with the aforementioned charging control circuit is not limited to batteries, but also includes card-type electronic money and RF ID (Radio Frequency Identification) tags etc. It is also possible to insert it. [Effects of the Invention]

[0047] By blocking the two paths connected to the battery, overcharging is detected and charging is quickly stopped. This reduces damage to the battery caused by overcharging.

[0048] A single flexible sheet on the side of the battery contains a protection circuit, a charging control circuit, and By incorporating an anomaly detection circuit, multiple prisms were implemented as IC chips. This eliminates the need for circuit boards, enabling the creation of smaller electronic devices without compromising functionality. [Brief explanation of the drawing]

[0049] [Figure 1]Figures 1A, 1B, and 1C are conceptual diagrams illustrating one aspect of the present invention. [Figure 2] Figure 2A is an example of a block diagram showing one aspect of the present invention, Figure 2B is an example of a circuit configuration, and Figure 2C is a diagram illustrating the Id-Vg characteristics of a transistor. [Figure 3] Figures 3A, 3B, and 3C are perspective views and conceptual diagrams illustrating one aspect of the present invention. [Figure 4] Figures 4A and 4B are an example of a block diagram and a flowchart illustrating one aspect of the present invention. [Figure 5] Figures 5A and 5B are conceptual diagrams illustrating one aspect of the present invention. [Figure 6] Figures 6A and 6B are perspective views showing one embodiment of the present invention. [Figure 7] Figure 7 is a cross-sectional view showing an example of the configuration of a semiconductor device. [Figure 8] Figures 8A, 8B, and 8C are cross-sectional views showing examples of transistor structures. [Figure 9] Figure 9A is a top view showing an example of transistor structure, and Figures 9B and 9C are cross-sectional views showing an example of transistor structure. [Figure 10] Figure 10A is a top view showing an example of transistor structure, and Figures 10B and 10C are cross-sectional views showing an example of transistor structure. [Figure 11] Figure 11A is a top view showing an example of transistor structure, and Figures 11B and 11C are cross-sectional views showing an example of transistor structure. [Figure 12] Figure 12A is a top view showing an example of transistor structure, and Figures 12B and 12C are cross-sectional views showing an example of transistor structure. [Figure 13] Figure 13A is a top view showing an example of transistor structure, and Figures 13B and 13C are cross-sectional views showing an example of transistor structure. [Figure 14] Figure 14A is a top view showing an example of transistor structure, and Figures 14B and 14C are cross-sectional views showing an example of transistor structure. [Figure 15]Figure 15A is a top view showing an example of transistor structure, and Figure 15B is a perspective view showing an example of transistor structure. [Figure 16] Figures 16A and 16B are cross-sectional views showing examples of transistor structures. [Figure 17] Figure 17 shows an example of an electronic device. [Figure 18] Figures 18A and 18B show examples of electronic devices. [Modes for carrying out the invention]

[0050] The embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is... Not limited to the following description, the form and details can be modified in various ways, as any person skilled in the art would know. This is easily understood. Furthermore, the present invention shall be interpreted as being limited to the contents of the embodiments described below. It's not something that can be done.

[0051] (Embodiment 1) Figure 1A shows a charging control circuit 1 formed on a flexible film substrate 11. This is a conceptual diagram of a wireless charging control system implemented on a cylindrical secondary battery 15. In Figure 1A, Vbat is the voltage of the secondary battery, and Vss and V- are the voltages of the charging control circuit. Voltage, Dout, and Cout are output terminals. The charging control system is a cylindrical secondary battery 1 5, the charging control circuit 10, the first switch 20, the charging circuit 16, and the antenna 30 They have at least one.

[0052] The cylindrical secondary battery 15 has a first terminal 12 on its upper surface and a second terminal 13 on its lower surface. It is connected to the first terminal 12 of the cylindrical secondary battery, and output from the cylindrical secondary battery 15. The first transmission path that transmits the power is electrically connected to the terminals of the charging control circuit via the electrode 18. It is done. Also, the second transmission line connected to the second terminal 13 of the cylindrical secondary battery is an electrode. It is connected to a first switch 20 that blocks the second transmission line via 19.

[0053] In Figure 1A, the first switch 20 (also called a disconnection switch) that disconnects the second transmission line and Then, two switching diodes, each consisting of a transistor and a diode, are connected. It functions as a protection circuit to prevent over-discharge, over-charge, or overcurrent. Switch 20 controls the conduction and interruption operations, and is a switch that switches between supply and interruption. It can also be called a step. The third terminal is the other terminal of the second transmission line formed on the flexible substrate 11. Terminal 14 is connected to the charging circuit 16 and the electronic device 17.

[0054] Furthermore, during charging, the cylindrical secondary power is transmitted from the antenna 30 (or receiving circuit) via the charging circuit 16. A third transmission path is also provided to supply power to battery 15.

[0055] A method for forming the charging control circuit 10 on a flexible substrate 11 involves forming it on a semiconductor substrate first... The method used involves removing the material using a peeling method and then fixing it onto the flexible substrate 11. In this regard, known techniques can be used. Also, after being formed on a semiconductor substrate, the back surface Alternatively, the material may be polished and then fixed onto the flexible substrate 11. Alternatively, the material may be precisely cut, so-called laser-cut, and then fixed onto the flexible substrate 11. Alternatively, the charging control circuit 10 may be directly formed on the flexible substrate 11. After the charging control circuit 10 formed on the substrate is peeled off using the peeling method, it is placed on the flexible substrate 11. A method of securing the device may also be used.

[0056] In this embodiment, the first switch 20, which consists of these switching diodes, is also flexible. An example of forming or mounting on a substrate 11 is shown, but the configuration is not limited to this.

[0057] If the charging control circuit 10 detects an abnormality such as a micro-short circuit, it will interrupt the second transmission path. The second transmission path is interrupted by inputting a signal to the gate of the first switch 20 that interrupts the transmission path. This is possible. By interrupting the second transmission line, the supply of current from the charging circuit 16 is stopped, or the power The supply of current to the sub-device 17 can be stopped. In addition, the second transmission line can be interrupted. The signal voltage applied to the gate of switch 20 is set to the memory circuit (a transistor using an oxide semiconductor) By holding it (including the 'T'), the blockage can be maintained for a long period of time.

[0058] Furthermore, if an abnormality such as a micro-short is detected, when the second transmission path is shut off, The output transistor (second switch) of the charging circuit 16 is turned off, blocking the third transmission path. By interrupting the power supply, a power transmission stop signal can be transmitted from antenna 30, thereby stopping power transmission. Therefore, This allows for a highly safe charging control system.

[0059] Figure 1B shows the cylindrical secondary battery 15 and the flexible substrate 11 just before they are bonded together. This is a process diagram showing the contact surface side of the flexible substrate 11. As shown in Figure 1B, it is flexible The body of the cylindrical secondary battery 15 is placed against the contact surface of the substrate 11 and rolled, and the circumferential direction of the body A flexible substrate 11 is wrapped around and attached in the direction. Also, electrodes 18 are attached to the flexible substrate 11 in the Y direction. The electrodes 19 are shown in a side-by-side arrangement, but this is not particularly limited, and one of them may be offset in the X direction. Figure 1C shows the figure after it has rolled.

[0060] An outer film is attached to cover the outer surface of the cylindrical secondary battery 15. The protective film protects the metal can that seals the internal structure of the secondary battery and provides insulation from the metal can. It is used to measure [something].

[0061] Without using an outer film, the outer surface (excluding the terminal portion) of the cylindrical secondary battery 15 is a metal surface. In that case, an insulating sheet is placed between the metal surface and electrode 18, and between the metal surface and electrode 19. Preferably, electrode 18 or electrode 19 is made of conductive metal foil or conductive material. These are adhesive tapes and lead wires, and the terminals of the cylindrical secondary battery 15, and soldering and wire bonding. The connection is made by known methods such as the charging method. Also, electrode 18 or electrode 19 is charged The terminals of the control circuit 10 are connected by soldering or wire bonding.

[0062] Conventionally, the IC chip is mounted on a circular rigid substrate that overlaps with the bottom surface of the cylindrical secondary battery. When using a protective circuit, physical pressure is applied because it is fitted into the socket and makes contact with the spring, and therefore This may cause malfunctions. In this invention, since it is provided on the side of the cylindrical secondary battery, Compared to the past, there is less physical pressure. Also, conventionally, a circular rigid base was used at the bottom. When the board is placed, the size of the battery needs to be reduced to fit the space, The quantity becomes smaller. In this invention, since it is provided on the side of the cylindrical secondary battery, compared to conventional methods. It is possible to save space without reducing capacity.

[0063] In this way, the charging control circuit 10 and protection circuit are provided on the curved surface region of the side of the cylindrical secondary battery 15. This is useful. For example, in the case of an 18650 battery, the diameter is 18 mm and the length is 65 mm. Therefore, the area of ​​the flexible substrate 11 is approximately the same as the lateral surface area of ​​the cylindrical secondary battery (in the X direction). The length will be 3.14 × 18 mm, and the length in the Y direction will be 65 mm or less. Also, 2 In the case of a 6650 battery, the diameter is 26 mm and the length is 65 mm, so the area of ​​the flexible substrate 11 is The length in the X direction is 3.14 × 26 mm, and the length in the Y direction is 65 mm.

[0064] Furthermore, if the cylindrical secondary battery 15 is an 18650 battery, attaching the flexible substrate 11 will allow it to be used. The curved region of the flexible substrate 11 has a radius of curvature of approximately 9 mm. Because the radius of curvature may not be uniformly approximately 9 mm due to the influence of wiring, this specification, etc., The smallest radius of curvature is taken as the radius of curvature of the surface. In cases where the curved surface has a shape with multiple centers of curvature... The sum is the curved surface with the smallest radius of curvature among the radii of curvature at each of the multiple centers of curvature. This refers to the radius of curvature. Depending on the size of the cylindrical secondary battery 15 used, the curvature The flexible substrate 11 is bent to a radius of 30 mm or more, preferably a radius of curvature of 9 mm or more. It is possible.

[0065] Furthermore, an example of a block diagram of the specific circuit of the charging control circuit 10 is shown in Figure 2A.

[0066] As shown in Figure 2A, the charging control circuit 10 of the secondary battery 15 includes a comparison circuit 102 and a first memory The system comprises at least a re 103, a second memory 104, and a control circuit 106.

[0067] In Figure 2A, the secondary battery 15 and the cutoff switch 105 (first switch) are connected to the charging control circuit 1 Although shown separately as 0, the cutoff switch 105 and the charging control circuit 10 are formed on the same circuit board. It is also possible.

[0068] The comparison circuit 102 compares the relative magnitudes of the two input voltages and outputs the result. Using a transistor with an oxide semiconductor in the channel formation region to create a unipolar circuit It's also possible.

[0069] The first memory 103 is an analog memory, and the analog power of the offset secondary battery The position is saved. The data of the offset secondary battery voltage value is stored in the first memory 103. Applying a write signal to the gate of a transistor generates a signal between the gate electrode and the drain electrode. It can be created by parasitic capacitance. The first memory 103 channels an oxide semiconductor It consists of one transistor and a capacitor in the memory formation region. The first memory 103 is high It can also be called a high-precision charging voltage monitoring circuit. Furthermore, the first memory 103 uses an oxide semiconductor. By taking advantage of the low leakage current of the transistors in the channel formation region... It is possible.

[0070] The second memory 104 has the same element configuration as the first memory 103, and is made of an oxide semiconductor (OS The second memory 1 is composed of one transistor having a channel formation region and a capacitor. 04 is responsible for holding the data of the disconnection switch 105 (first switch).

[0071] The cutoff switch 105 (first switch) cuts off the power supply to the secondary battery when a malfunction occurs. This is a switch for interrupting the power supply. The interruption switch 105 has the circuit configuration shown in Figure 2A. This causes the malfunctioning secondary battery 15 to continue charging, leading to overcharging and subsequent fire. This can prevent that from happening. Furthermore, the charging control circuit 10 controls the output transistor of the charging circuit Turning it off reduces the risk of overcharging.

[0072] In Figure 2A, after detecting an abnormality using the cutoff switch 105 (first switch), the secondary battery 1 The example shows stopping the power supply to 5, but the charging conditions are adjusted according to the number of times an anomaly is detected. You may make changes, pause charging, or display warnings.

[0073] Furthermore, it can be used in the first memory 103 and the second memory 104 shown in Figure 2A. Figure 2B shows a memory cell. Figure 2B shows a memory cell with a back gate in the transistor. This is an example of the circuit configuration for the Ricell 100.

[0074] The memory cell 100 has a transistor M1 and a capacitive element CA. The Star M1 has a front gate (also simply called the "gate") and a rear gate. The back gate is positioned so that the channel formation region of the semiconductor layer is sandwiched between the gate and the back gate. They are positioned. Note that the terms "gate" and "back gate" are for convenience only, and one of them is referred to as "Gate". When one is called a "gate," the other is called a "backgate." Therefore, gate and backgate The names can be used interchangeably. Either the gate or the back gate is called " Sometimes it is called the "first gate" and the other the "second gate."

[0075] Either the source or drain of transistor M1 is electrically connected to one electrode of capacitive element CA. The source or drain of transistor M1 is connected to the bit line BL or bit line. The gate of transistor M1 is electrically connected to the word line WL, and the gate of transistor M1 is electrically connected to the word line WL. The back gate of transistor M1 is connected to the wiring BGL and is electrically connected to the wiring BGL. The other electrode of the capacitive element CA is connected to the wiring CAL.

[0076] The wiring CAL functions as a wire for applying a predetermined potential to the other electrode of the capacitive element CA. When writing and reading data, the wiring CAL has VSS and other It is preferable to supply a fixed potential.

[0077] Wiring BGL functions as wiring to apply potential to the back gate of transistor M1. do.

[0078] Figure 2C shows an example of the Id-Vg characteristic, one of the electrical characteristics of a transistor. The g characteristic shows the change in drain current (Id) in response to a change in gate voltage (Vg). Figure 2 The horizontal axis of Figure 2C shows Vg on a linear scale. The vertical axis of Figure 2C shows Id on a logarithmic scale. This is shown in the diagram. As shown in Figure 2C, the back gate voltage (Vbg) and When a positive bias voltage +Vbg is supplied, the Id-Vg characteristic changes to the negative side of Vg. It shifts in the direction. When a negative bias voltage -Vbg is supplied to wiring BGL, Id-Vg The characteristic shifts in the positive direction of Vg. The amount of shift in the Id-Vg characteristic is supplied to the wiring BGL. It is determined by the magnitude of the applied voltage. By adjusting the voltage applied to wiring BGL, the traction can be controlled. The threshold voltage of the inverter M1 can be increased or decreased.

[0079] Data writing and reading are performed by conducting transistor M1 to the word line WL (on). A potential is supplied to the state, and transistor M1 is made to conduct, and the bit line BL or bit This is done by electrically connecting one electrode of the tap wire BLB and the capacitive element CA.

[0080] By using an OS transistor as transistor M1, the regeneration of transistor M1 The current can be kept very low. In other words, the long-term retention of written data is not affected. This is made possible by the M1, which reduces the frequency of memory cell refresh. This can be done. Furthermore, it eliminates the need for memory cell refresh operations. Also, Because the current is very low, analog data can be stored in the memory cell.

[0081] As shown in Figure 1A, when power is supplied from a cylindrical secondary battery 15 to an electronic device 17, The cylindrical secondary battery 15 enters a discharge state, and the voltage at the first terminal 12 and the second terminal 13 decreases. The charging control circuit 10 monitors the behavior of the current and other parameters, and if an abnormality is detected, the first switch The second transmission line is interrupted by the 20, stopping the discharge.

[0082] Electronic device 17 refers to components other than the secondary battery, and the power source for electronic device 17 is a cylinder This is a rechargeable battery 15. Note that the electronic device 17 includes mobile devices that can be carried around. nothing.

[0083] Furthermore, when charging a cylindrical secondary battery 15 by wireless power supply, the cylindrical secondary battery Battery 15 enters a charged state. Voltage, current, etc. at the first terminal 12 and the second terminal 13. The behavior is monitored by the charging control circuit 10, and if an abnormality is detected, the second transmission line and the third transmission line are... The power supply is cut off to stop charging.

[0084] The charging circuit 16 refers to a circuit that transmits power using wireless signals. 6 may also be built into electronic devices 17.

[0085] An example of a charging circuit 16 being built into an electronic device 17 is described. The electronic device 17 has multiple It incorporates a rigid circuit board with the circuitry implemented inside, and uses a battery with a charging control circuit wrapped around it as its power source. The processor 23, power supply circuit 24, charging circuit 16, and power receiving circuit 22 are implemented on a rigid board. The block diagram is shown in Figure 4A. Note that parts are common to both Figure 4A and Figure 1A. The same sign is used for the minutes. Note that in Figure 4A, the primary coil 31 and the secondary coil (A The Tena 30) is electrically connected to the terminals of the rigid board as an antenna module.

[0086] Figure 4B shows one charge cycle for an electronic device 17 equipped with a charging control circuit 10 on a secondary battery 15. This shows an example of the flow of a charging control system when overcharging is detected.

[0087] First, the charging control circuit 10 detects overcharging (S1). Next, the charging control circuit 10 shuts down The first switch 20, which is a cutoff switch, is turned off, and the charging circuit 16 detects overcharging. Notify that the action has been taken (S2).

[0088] Next, the charging circuit 16 stops charging by turning off the output transistor of the charging circuit 16. The system stops and notifies the power receiving circuit 22 that charging is complete (S3). The power receiving circuit 22 sends a signal to the power transmitting side. Then, power transmission is stopped (S4). Finally, transmission from the primary coil 31 is stopped, and charging The power supply is shut off (S5).

[0089] Furthermore, while this document primarily describes a configuration for detecting overcharge, it is not limited to such configurations, and overcurrent protection is also possible. The same workflow can be used to detect anomalies such as malfunctions and micro-short circuits.

[0090] The above charging control system makes it possible to shut down multiple circuits almost simultaneously after detecting an anomaly. That is the case.

[0091] Here, we will explain cylindrical secondary batteries with reference to Figures 3A and 3B. Cylindrical secondary batteries 15 has a positive electrode cap (battery cover) 201 on its top surface, as shown in Figure 3B, and on its sides and The bottom has a battery can (outer casing) 202. These positive electrode cap and battery can (outer casing) 2 02 is insulated by gasket (insulating packing) 210.

[0092] Figure 3B is a schematic diagram showing a cross-section of a cylindrical secondary battery. The hollow cylindrical battery casing 202 Inside, a strip-shaped positive electrode 204 and a negative electrode 206 are wound around a separator 205 in between. A battery element is provided. Although not shown in the diagram, the battery element is wound around a center pin. The battery can 202 is closed at one end and open at the other. The battery can 202 contains electrolytic Metals such as nickel, aluminum, and titanium, or alloys thereof, that are corrosion-resistant to liquids. Alloys of these with other metals (for example, stainless steel) can be used. To prevent corrosion from the electrolyte, it is preferable to coat the device with nickel, aluminum, or the like. Inside the battery container 202, the battery element, in which the positive electrode, negative electrode, and separator are wound, is opposite It is sandwiched between a pair of insulating plates 208 and 209. Furthermore, a battery element is provided. The inside of can 202 is filled with a non-aqueous electrolyte (not shown). The secondary battery is made of cobalt acid. Positive compounds containing active materials such as lithium (LiCoO2) and lithium iron phosphate (LiFePO4) An electrode, a negative electrode made of a carbon material such as graphite capable of intercalating and releasing lithium ions, and ethylene Organic solvents such as carbonates and diethyl carbonates contain lithium such as LiBF4 and LiPF6. It is composed of a non-aqueous electrolyte solution containing an electrolyte made of thium salts.

[0093] Since the positive and negative electrodes used in cylindrical secondary batteries are wound, active material is formed on both sides of the current collector. It is preferable that the positive electrode 204 is connected to the positive electrode terminal (positive electrode current collector lead) 203, and the negative electrode The negative terminal (negative current collector lead) 207 is connected to 206. Positive terminal 203 and negative terminal Terminals 207 can both be made of metal materials such as aluminum. Positive terminal 20 Terminal 3 is resistance-welded to the safety valve mechanism 212, and the negative terminal 207 is resistance-welded to the bottom of the battery can 202. The safety valve mechanism 212 is a PTC (Positive Temperature Coefficient). It is electrically connected to the positive electrode cap 201 via the (ficient) element 211. The valve mechanism 212, when the rise in the internal pressure of the battery exceeds a predetermined threshold, and the positive electrode cap 201 and This disconnects the electrical connection with the positive electrode 204. Also, the PTC element 211 is at a higher temperature. This is a thermal resistance element whose resistance increases when the temperature rises, and by increasing the resistance, it limits the amount of current. This prevents overheating. The PTC element uses a barium titanate (BaTiO3) semiconductor. Conductive ceramics and the like can be used.

[0094] A lithium-ion secondary battery using an electrolyte consists of a positive electrode, a negative electrode, a separator, and an electrolyte. It has an outer casing. In lithium-ion secondary batteries, the anode (positive electrode) is used during charging and discharging. The cathode is swapped, and the oxidation and reduction reactions are reversed, 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 the details, whether charging or discharging, when a reverse pulse current is applied... Even when charging current is flowing, the positive terminal is still called the "positive terminal" or "+ terminal (positive terminal)". Furthermore, the negative electrode will be referred to as the "negative electrode" or "- electrode (minus electrode)". Oxidation reactions and reduction reactions Using the related terms anode and cathode, we can understand the relationship between charging and discharging. At times, the opposite can occur, potentially causing confusion. Therefore, the anode (positive electrode) The terms "cathode" and "neutral electrode" will not be used in this specification. When using the terms anode and cathode, specify whether it refers to charging or discharging. Furthermore, it should also be indicated whether it corresponds to the positive (or negative) pole. ru.

[0095] The charger is connected to the two terminals shown in Figure 3C, and the battery 1400 is charged. In this diagram, 1406 is the electrolyte and 1408 is the separator. The charging of battery 1400 is progressing. Then, the potential difference between the electrodes increases. In Figure 3C, from the external terminal of the battery 1400, positive The current flows towards electrode 1402, and within the battery 1400, from positive electrode 1402 to negative electrode 1404. The direction of the current flowing from the negative terminal towards the external terminal of the battery 1400 is defined as the positive direction. In other words, the direction in which the charging current flows is considered the direction of the current.

[0096] In this embodiment, an example of a lithium-ion secondary battery is shown, but it is not limited to lithium-ion secondary batteries. It is not specified, and for example, a material having elements A, X, and oxygen is used as the positive electrode material for a secondary battery. It can be used. Element A is one or more elements selected from the elements of Group 1 and the elements of Group 2. It is preferable to use elements from Group 1, such as lithium, sodium, potassium, etc. Lucali metals can be used. Also, as Group 2 elements, for example, calcium, beryl Element X can be a metallic element, such as silicon. One or more elements selected from phosphorus may be used. Furthermore, element X may be cobalt, nickel, etc. Preferably, it is one or more selected from manganese, iron, and vanadium. Typically, Lithium cobalt composite oxide (LiCoO2) and lithium iron phosphate (LiFePO4) ) are some examples.

[0097] The negative electrode has a negative electrode active material layer and a negative electrode current collector. The negative electrode active material layer also contains a conductive additive and It may have a binder.

[0098] As a negative electrode active material, it is possible to perform charge and discharge reactions through alloying and dealloying reactions with lithium. Any suitable element can be used. For example, silicon, tin, gallium, aluminum, galvanic acid. Among the following, a small amount is found in luminum, lead, antimony, bismuth, silver, zinc, cadmium, indium, etc. Materials containing at least one element can be used. Such elements have a larger capacity compared to carbon. Yes, especially silicon, which has a high theoretical capacity of 4200mAh / g.

[0099] Furthermore, it is preferable that the secondary battery has a separator. Examples of separators include: Paper and other cellulose-containing fibers, nonwoven fabrics, glass fibers, ceramics, or Nylon (polyamide), Vinylon (polyvinyl alcohol-based fiber), polyester, A This product uses synthetic fibers made from acrylic, polyolefin, polyurethane, etc. It is possible.

[0100] (Embodiment 2) In this embodiment, another structural example of the cylindrical secondary battery of Embodiment 1 is shown in Figures 5 and 6. We will explain using this method.

[0101] Figure 5A shows a flat-shaped secondary battery 913, a charging control circuit 914, and a connection terminal 911. This is a diagram showing the external appearance of the battery pack.

[0102] The charging control circuit 914 is formed or fixed on the flexible substrate 910. The 914 detects abnormalities such as micro-shorts. Furthermore, it detects overcharging, over-discharging, and over-voltage. It may also function as a protection circuit to protect the secondary battery 913 from current.

[0103] The charging control circuit 914 can be the same as the charging control circuit 10 shown in Embodiment 1. Since the same circuit configuration can be used, a detailed explanation will be omitted here. Let's assume that.

[0104] Furthermore, in addition to the charging control circuit 914, an antenna and a power receiving circuit are provided as shown in Figure 4A. This is also good. The secondary battery 913 can also be charged wirelessly using an antenna. Antenna It is not limited to a coil shape, but may also be linear, plate-shaped, etc. Also, planar antenna, open Antennas such as surface antennas, traveling wave antennas, EH antennas, magnetic field antennas, dielectric antennas, etc. An antenna may be used. The antenna can, for example, perform data communication with external devices. It has the function. The communication method between the battery pack and other devices via the antenna is NFC. Furthermore, it is possible to apply response methods that can be used between the battery pack and other devices. Cut.

[0105] As shown in Figure 5B, the connection terminal 911 connects to the secondary battery 913 via the charging control circuit 914. It is electrically connected to terminals 951 and 952 of the device. Note that the connection terminal 911 is double By providing several of these, each of the multiple connection terminals 911 can be used as a control signal input terminal, a power terminal, etc. That's good too.

[0106] The battery pack has an insulating sheet layer 916 between the charging control circuit 914 and the secondary battery 913. The insulating sheet layer 916 has the function of preventing short circuits caused by, for example, the secondary battery 913. For the insulating sheet layer 916, for example, an organic resin film or an adhesive sheet can be used. Cut.

[0107] Furthermore, an example of the internal structure of the secondary battery 913 will be explained using Figure 6.

[0108] Figure 6A shows the structure of the winding body 950 located inside the secondary battery 913. 50 has a negative electrode 931, a positive electrode 932, and a separator 933. The wound body 950 is The negative electrode 931 and the positive electrode 932 are stacked on top of each other with a separator 933 in between, and the stacked This is a wound body made by winding a sheet. It consists of a negative electrode 931, a positive electrode 932, and a separator 93. You may further stack layers 3 and .

[0109] The negative electrode 931 is connected to the connection terminal 911 shown in Figure 5 via either terminal 951 or terminal 952. The positive terminal 932 is connected to the connection terminal shown in Figure 5 via terminals 951 and the other of terminal 952. Connects to 911.

[0110] The wound body 950 shown in Figure 6A is impregnated with an electrolyte solution inside the outer casing. The outer casing is made of metal. A housing is used. In some cases, a film is used for the exterior, and in that case, the film In some cases, a charging control circuit formed on a flexible substrate may be provided.

[0111] The secondary battery 913 shown in Figure 6B has terminals 951 and 952 inside the housing 930. It has a wound body 950. The wound body 950 is impregnated with an electrolyte inside the housing 930. The child 952 is in contact with the housing 930, and the terminal 951 is connected to the housing 93 by using an insulating material or the like. It is not touching zero. Note that in Figure 6B, the housing 930 is shown separately for convenience. However, in reality, the coiled body 950 is covered by the housing 930, and terminals 951 and 952 are covered by the housing 93 It extends outside of 0. The housing 930 is made of a metal material (e.g., aluminum) or Resin materials can be used.

[0112] For the casing 930, insulating materials such as metal materials and organic resins can be used.

[0113] In Figure 5A, an insulating sheet layer 916 is provided on the surface of the housing, and the surface on which the charging control circuit is installed is The example shown involves fixing the flexible substrate on the inside, but it is not limited to this, and the charging control circuit. The surface in which the feature is formed may be facing outwards when connecting to terminals 951 and 952. In that case, the connection point would be exposed, posing a risk of electrostatic discharge or short circuit. Careful assembly is required.

[0114] The charging control circuit 914, which is electrically connected to the connection terminal 911, is the charging control circuit shown in Embodiment 1. Since it is a control circuit 10, it can be a highly safe secondary battery 913.

[0115] This embodiment can be freely combined with Embodiment 1.

[0116] (Embodiment 3) In this embodiment, the charging control circuit 10 described in the above embodiment can be used, The configuration example of the OS transistor will be described. Note that the OS transistor is a thin film transistor, which can be formed on a release layer provided on a glass substrate or laminated and provided on a single crystal silicon substrate. Since the first embodiment is an example in which a flexible substrate provided with a charge control circuit is attached to the curved surface of the secondary battery, the OS transistor formed on the release layer provided on the glass substrate is fixed to the flexible substrate by a known release method. Also, since the second embodiment is an example in which a charge control circuit is attached to the flat surface of the secondary battery, after forming the OS transistor on the single crystal silicon substrate, for example, the back surface of the single crystal silicon substrate is polished and thinned and fixed to the flexible substrate.

[0117] The first embodiment is an example in which a flexible substrate provided with a charge control circuit is attached to the curved surface of the secondary battery. Therefore, the OS transistor formed on the release layer provided on the glass substrate is fixed to the flexible substrate by a known release method. Since the first embodiment is an example in which a flexible substrate provided with a charge control circuit is attached to the curved surface of the secondary battery, the OS transistor formed on the release layer provided on the glass substrate is fixed to the flexible substrate by a known release method. Also, since the second embodiment is an example in which a charge control circuit is attached to the flat surface of the secondary battery, after forming the OS transistor on the single crystal silicon substrate, for example, the back surface of the single crystal silicon substrate is polished and thinned and fixed to the flexible substrate. Also, since the second embodiment is an example in which a charge control circuit is attached to the flat surface of the secondary battery, after forming the OS transistor on the single crystal silicon substrate, for example, the back surface of the single crystal silicon substrate is polished and thinned and fixed to the flexible substrate. For example, the back surface of the single crystal silicon substrate is polished and thinned and fixed to the flexible substrate. Alternatively, the OS transistor may be separated from the single crystal silicon substrate by using the hydrogen ion implantation and release method and fixed to the flexible substrate. Alternatively, the OS transistor may be separated from the single crystal silicon substrate by using the hydrogen ion implantation and release method and fixed to the flexible substrate.

[0118] Hereinafter, in this embodiment, a configuration example of a semiconductor device in which an OS transistor is provided above a Si transistor formed on a single crystal silicon substrate will be described. Hereinafter, in this embodiment, a configuration example of a semiconductor device in which an OS transistor is provided above a Si transistor formed on a single crystal silicon substrate will be described.

[0119] <Configuration example of semiconductor device>[ The semiconductor device shown in FIG. 7 has a transistor 300, a transistor 500, and a capacitor element 600. FIG. 8A is a cross-sectional view of the transistor 500 in the channel length direction, FIG. 8B is a cross-sectional view of the transistor 500 in the channel width direction, and FIG. 8C is a cross-sectional view of the transistor 300 in the channel width direction. The semiconductor device shown in FIG. 7 has a transistor 300, a transistor 500, and a capacitor element 600. FIG. 8A is a cross-sectional view of the transistor 500 in the channel length direction, FIG. 8B is a cross-sectional view of the transistor 500 in the channel width direction, and FIG. 8C is a cross-sectional view of the transistor 300 in the channel width direction. FIG. 8A is a cross-sectional view of the transistor 500 in the channel length direction, FIG. 8B is a cross-sectional view of the transistor 500 in the channel width direction, and FIG. 8C is a cross-sectional view of the transistor 300 in the channel width direction. <​​​​​​​​It can be cut, the off-current is difficult to increase even in a high-temperature environment, and the ratio of the on-current to the off-current is large even in a high-temperature environment. Therefore, in the above embodiment, this is used for the charge control circuit 10. By doing so, the mobile device can be made into a highly safe semiconductor device.

[0121] As shown in FIG. 7, the semiconductor device described in this embodiment includes a transistor 300, a transistor 500, and a capacitive element 600. The transistor 500 is provided above the transistor 30 0, and the capacitive element 600 is provided above the transistor 300 and the transistor 500.

[0122] The transistor 300 is provided on a substrate 311 and includes a conductor 316, an insulator 315, a semiconductor region 313 formed of a part of the substrate 3 11, and low-resistance regions 314a and 314b that function as a source region or a drain region.

[0123] As shown in FIG. 8C, the upper surface of the semiconductor region 313 and the side surface in the channel width direction of the transistor 300 are covered by the conductor 316 via the insulator 315. In this way, by making the transistor 3 00 a Fin type, the effective channel width increases, thereby improving the on-characteristics of the transistor 3 00. In addition, since the contribution of the electric field of the gate electrode can be increased, the off-characteristics of the transistor 300 can be improved.

[0124] Note that the transistor 300 may be either a p-channel type or an n-channel type.

[0125] The region where the channel of the semiconductor region 313 is formed, the region in the vicinity thereof, the source region, or the drain In the low-resistance region 314a and low-resistance region 314b, which are rain regions, silico It is preferable that the semiconductor contains semiconductors such as silicon-based semiconductors, and it is preferable that it contains single-crystal silicon. Alternatively, Ge (germanium), SiGe (silicon germanium), GaAs (galvanium) It may also be formed from materials containing arginine, GaAlAs (gallium aluminum arsenide), etc. By applying stress to the crystal lattice and changing the lattice spacing, silicon with controlled effective mass is produced. The configuration used may also be used. Alternatively, by using GaAs and GaAlAs, etc., the transient TA300 is HEMT (High Electron Mobility Transit) You can also use "tor)".

[0126] Low-resistance regions 314a and 314b are semiconductor regions applied to semiconductor region 313. In addition to the main material, elements that impart n-type conductivity, such as arsenic and phosphorus, or p-type conductivity, such as boron. It contains elements that impart conductivity.

[0127] The conductor 316, which functions as a gate electrode, is a component that imparts n-type conductivity, such as arsenic or phosphorus. Semiconductor materials such as silicon containing elements that impart p-type conductivity, such as boron or other elements. Conductive materials such as metallic materials, alloy materials, or metal oxide materials can be used.

[0128] Furthermore, since the work function is determined by the material of the conductor, by changing the material of the conductor, The Vth of the transistor can be adjusted. Specifically, titanium nitride or titanium nitride can be used as the conductor. It is preferable to use materials such as tar. Furthermore, in order to achieve both conductivity and embedding properties It is preferable to use a laminate of metal materials such as tungsten or aluminum as the conductive material. , in particular, using tungsten is preferable in terms of heat resistance.

[0129] Note that the transistor 300 shown in FIG. 7 is an example and is not limited to its structure, and an appropriate transistor may be used according to the circuit configuration and driving method.

[0130] Covering the transistor 300, the insulator 320, the insulator 322, the insulator 324, and the insulator 326 are sequentially laminated and provided.

[0131] 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, aluminum nitride, etc. may be used.

[0132] The insulator 322 may have a function as a planarization film that planarizes the step generated by the transistor 300 or the like provided below it. For example, the upper surface of the insulator 322 may be planarized by a planarization process using a chemical mechanical polishing (CMP) method or the like in order to enhance flatness.

[0133] Further, in the region where the transistor 500 is provided on the substrate 311 or the transistor 300 or the like, the insulator 324 preferably has a film having a barrier property such that hydrogen and impurities do not diffuse.

[0134] As an example of a film having a barrier property against hydrogen, for example, silicon nitride formed by CVD can be used. Here, when hydrogen diffuses into a semiconductor element having an oxide semiconductor such as the transistor 500, the characteristics of the semiconductor element may deteriorate. Therefore, ​​​​​​​​​A film that suppresses hydrogen diffusion is used between transistor 500 and transistor 300. It is preferable to have one. Specifically, a membrane that suppresses hydrogen diffusion is one that minimizes hydrogen desorption. It will form a membrane.

[0135] The amount of hydrogen desorption can be analyzed using methods such as thermal desorption gas analysis (TDS analysis). This can be done. For example, the amount of hydrogen desorbed from insulator 324 is determined by TDS analysis, and the film surface temperature In the range of 50°C to 500°C, the amount of desorption converted to hydrogen atoms is on the surface of the insulator 324. Converted to a unit per unit, 10 x 10 15 atoms / cm 2 The following is preferably 5 × 10 15 atoms / cm 2 The following is acceptable.

[0136] Furthermore, it is preferable that the dielectric constant of the insulator 326 is lower than that of the insulator 324. For example, insulation The relative permittivity of body 326 is preferably less than 4, and more preferably less than 3. Also, for example, insulator 3 The relative permittivity of 26 is preferably 0.7 times or less the relative permittivity of the insulator 324, and preferably 0.6 times or less. More preferable. By using a material with a low dielectric constant as the interlayer film, the parasitic capacitance that occurs between the wiring is reduced. It can be reduced.

[0137] Furthermore, insulators 320, 322, 324, and 326 contain capacitive elements 6 00, or conductors 328 and 330 connected to transistor 500 are embedded. It is included. Note that conductors 328 and 330 are used as plugs or wiring. It has a function. Furthermore, a conductor that functions as a plug or wiring has multiple structures. In some cases, the same symbol may be assigned to them. Also, in this specification, wiring and connections The connecting plug may be an integrated part. That is, a part of the conductor functions as wiring. In some cases, and sometimes even a portion of the conductor functions as a plug.

[0138] The materials for each plug and wiring (conductor 328, conductor 330, etc.) are metal materials. Conductive materials such as materials, alloy materials, metal nitride materials, or metal oxide materials are used in a single layer or It can be used in a layered configuration. Materials such as tungsten and molybdenum offer both heat resistance and conductivity. It is preferable to use a high melting point material, and it is preferable to use tungsten. Alternatively, It is preferable to form it with a low-resistance conductive material such as aluminum or copper. Low-resistance conductive material By using this method, wiring resistance can be reduced.

[0139] A wiring layer may be provided on the insulator 326 and the conductor 330. For example, in Figure 7 Insulators 350, 352, and 354 are arranged in a sequential stack. Furthermore, a conductor 356 is formed on insulators 350, 352, and 354. Conductor 356 functions as a plug or wire connecting to transistor 300. It has the same material as conductors 328 and 330. It can be established.

[0140] For example, insulator 350 has a barrier property against hydrogen, similar to insulator 324. It is preferable to use an insulator. Furthermore, the conductor 356 has barrier properties against hydrogen. It is preferable that it contains a conductor. In particular, the insulator 350 having barrier properties against hydrogen is preferable. A conductor having a barrier property against hydrogen is formed in the opening. With this configuration, Transistor 300 and transistor 500 can be separated by a barrier layer. This can suppress the diffusion of hydrogen from transistor 300 to transistor 500.

[0141] For example, tantalum nitride can be used as a conductor that has barrier properties against hydrogen. This is good. Also, by laminating tantalum nitride and highly conductive tungsten, the wiring can be This allows for the suppression of hydrogen diffusion from transistor 300 while maintaining conductivity. In this case, the tantalum nitride layer having barrier properties against hydrogen provides a barrier against hydrogen. It is preferable that the structure is in contact with the insulator 350.

[0142] A wiring layer may be provided on the insulator 354 and the conductor 356. For example, in Figure 7 Insulators 360, 362, and 364 are arranged in a series of layers. Furthermore, a conductor 366 is formed on insulators 360, 362, and 364. Conductor 366 has the function of a plug or wiring. It can be provided using the same material as conductors 328 and 330.

[0143] For example, insulator 360 has a barrier property against hydrogen, similar to insulator 324. It is preferable to use an insulator. Furthermore, the conductor 366 has barrier properties against hydrogen. It is preferable that it contains a conductor. In particular, the insulator 360 having barrier properties against hydrogen is preferable. A conductor having a barrier property against hydrogen is formed in the opening. With this configuration, Transistor 300 and transistor 500 can be separated by a barrier layer. This can suppress the diffusion of hydrogen from transistor 300 to transistor 500.

[0144] A wiring layer may be provided on the insulator 364 and the conductor 366. For example, in Figure 7 Insulators 370, 372, and 374 are arranged in a sequential stack. Furthermore, a conductor 376 is formed on insulators 370, 372, and 374. It is present. Conductor 376 has the function of a plug or wiring. Note that Conductor 376 is It can be provided using the same material as conductors 328 and 330.

[0145] For example, insulator 370 has a barrier property against hydrogen, similar to insulator 324. It is preferable to use an insulator. Furthermore, the conductor 376 has barrier properties against hydrogen. It is preferable that it contains a conductor. In particular, the insulator 370 having barrier properties against hydrogen is preferable. A conductor having a barrier property against hydrogen is formed in the opening. With this configuration, Transistor 300 and transistor 500 can be separated by a barrier layer. This can suppress the diffusion of hydrogen from transistor 300 to transistor 500.

[0146] A wiring layer may be provided on the insulator 374 and the conductor 376. For example, in Figure 7 Insulators 380, 382, ​​and 384 are arranged in a sequential stack. Furthermore, a conductor 386 is formed on insulators 380, 382, ​​and 384. Conductor 386 functions as a plug or wiring. It can be provided using the same material as conductors 328 and 330.

[0147] For example, insulator 380 has a barrier property against hydrogen, similar to insulator 324. It is preferable to use an insulator. Furthermore, the conductor 386 has barrier properties against hydrogen. It is preferable that it contains a conductor. In particular, the insulator 380 having barrier properties against hydrogen is preferable. A conductor having a barrier property against hydrogen is formed in the opening. With this configuration, Transistor 300 and transistor 500 can be separated by a barrier layer. This can suppress the diffusion of hydrogen from transistor 300 to transistor 500.

[0148] In the above, a wiring layer containing a conductor 356, a wiring layer containing a conductor 366, and a conductor 376 The wiring layer including the conductive 386 has been described, but this embodiment is not applicable. The semiconductor device is not limited to this. A wiring layer similar to a wiring layer containing conductor 356 The number of layers may be three or less, or the wiring layers similar to the wiring layer containing the conductor 356 may be made five or more layers. That's good too.

[0149] Insulator 384 has insulators 510, 512, 514, and 516. They are arranged in a stack in order. Insulator 510, insulator 512, insulator 514, and insulating It is preferable that one of the surrounding bodies 516 be made of a material that has barrier properties against oxygen and hydrogen. stomach.

[0150] For example, the insulator 510 and the insulator 514 have, for example, a substrate 311 or a transient From the area where transistor 300 is installed, hydrogen and impurities are present in the area where transistor 500 is installed. It is preferable to use a film that has barrier properties to prevent diffusion. Therefore, insulator 32 The same materials as in 4 can be used.

[0151] As an example of a film with hydrogen barrier properties, silicon nitride formed by CVD is used. This can be done. Here, a semiconductor device having an oxide semiconductor such as transistor 500, Hydrogen diffusion can degrade the properties of the semiconductor device. Therefore, A film that suppresses hydrogen diffusion is used between transistor 500 and transistor 300. This is preferable. Specifically, a membrane that suppresses hydrogen diffusion is a membrane that releases less hydrogen. .

[0152] Furthermore, as films having barrier properties against hydrogen, for example, insulator 510 and insulator 5 14 uses metal oxides such as aluminum oxide, hafnium oxide, and tantalum oxide. It is preferable.

[0153] In particular, aluminum oxide is a source of oxygen and hydrogen, which can cause variations in the electrical properties of transistors. It has a high barrier effect that prevents both water and other impurities from passing through the film. Aluminum oxide is susceptible to hydrogen, moisture, and other elements during and after the transistor fabrication process. This prevents impurities from entering transistor 500. This can suppress the release of oxygen from the oxides that make up the transistor. It is suitable for use as a protective film against 500.

[0154] Furthermore, for example, the same material as the insulator 320 is used for insulators 512 and 516. It is possible to have it there. Also, by using a material with a relatively low dielectric constant as the interlayer film, it can prevent the formation of a barrier between the wiring. This can reduce parasitic capacitance. For example, as insulator 512 and insulator 516 Silicon oxide films and silicon oxide nitride films can be used.

[0155] Furthermore, insulators 510, 512, 514, and 516 contain a conductor 5 18, and a conductor (conductor 503) etc. that constitutes the transistor 500 are embedded. The conductor 518 is connected to the capacitive element 600 or the transistor 300. It functions as a wire or a conductor. Conductor 518 is connected to conductor 328 and conductor 3 It can be provided using the same materials as in 30.

[0156] In particular, the conductor 518 in the region in contact with the insulator 510 and the insulator 514 is oxygen, hydrogen, And preferably it is a conductor that has barrier properties against water. With this configuration, Transistor 300 and Transistor 500 have barrier properties against oxygen, hydrogen, and water. In the layer, it can be separated, and hydrogen from transistor 300 to transistor 500 It can suppress diffusion.

[0157] A transistor 500 is provided above the insulator 516.

[0158] As shown in Figures 8A and 8B, transistor 500 has insulator 512 and insulator 516 A conductor 503 is arranged to be embedded in the insulator 516 and on top of the conductor 503. An insulator 520 placed on top of an insulator 520, and an insulator 522 An insulator 524 placed on top of, an oxide 530a placed on top of the insulator 524, and an acid An oxide 530b is placed on the oxide 530a, and on the oxide 530b, spaced apart from each other. The placed conductors 542a and 542b, and conductors 542a and 542 An insulating material is placed on b and has an opening formed in superimposed between the conductor 542a and the conductor 542b. Body 580, conductor 560 placed in the opening, oxide 530b, conductor 542a, Insulator 55 is placed between the conductor 542b, the insulator 580, and the conductor 560. 0, oxide 530b, conductor 542a, conductor 542b, and insulator 580, insulation It comprises a body 550 and an oxide 530c disposed between them.

[0159] Furthermore, as shown in Figures 8A and 8B, oxide 530a, oxide 530b, and conductor 542a It is preferable that an insulator 544 be placed between the conductor 542b and the insulator 580. Furthermore, as shown in Figures 8A and 8B, the conductor 560 is provided inside the insulator 550. A conductive material 560a and a conductive material 5 provided so as to be embedded inside the conductive material 560a. It is preferable to have 60b. Also, as shown in Figures 8A and 8B, the insulator 580 Preferably, the insulator 574 is placed on top of the conductor 560 and the insulator 550.

[0160] In the following, oxides 530a, 530b, and 530c are grouped together. In some cases, it is referred to as oxide 530. Also, conductors 542a and 542b are grouped together. In some cases, it is referred to as conductor 542.

[0161] Furthermore, in transistor 500, oxidation occurs in the region where the channel is formed and in its vicinity. The following describes a configuration in which three layers of material 530a, oxide 530b, and oxide 530c are laminated. However, the present invention is not limited thereto. For example, a single layer of oxide 530b, oxidation Two-layer structure of substance 530b and oxide 530a, two-layer structure of oxide 530b and oxide 530c, Alternatively, a configuration with a stacked structure of four or more layers may be used. Furthermore, in transistor 500, Although the conductor 560 is shown as a two-layer laminated structure, the present invention is not limited thereto. For example, the conductor 560 may have a single-layer structure or a laminated structure of three or more layers. This is also fine. Furthermore, the transistor 500 shown in Figures 7, 8A, and 8B is just one example, and its structure It is not limited to this; an appropriate transistor should be used depending on the circuit configuration and driving method.

[0162] Here, conductor 560 functions as the gate electrode of the transistor, and conductor 542a and The conductor 542b functions as either a source electrode or a drain electrode, respectively. In addition, the conductor 560 is connected to the opening of the insulator 580, and to the conductors 542a and 542b. It is formed so as to be embedded in the sandwiched region. Conductor 560, Conductor 542a and Conductor The arrangement of the electric element 542b is selected in a self-aligned manner with respect to the opening of the insulator 580. In transistor 500, the gate electrode is connected between the source electrode and the drain electrode, self It can be arranged in a consistent manner. Therefore, the conductor 560 is provided with a margin for alignment. Since it can be formed without any additional steps, the occupied area of ​​transistor 500 can be reduced. This makes it possible to miniaturize and highly integrate semiconductor devices.

[0163] Furthermore, the conductor 560 is formed in a self-aligned manner in the region between conductor 542a and conductor 542b. Therefore, the conductor 560 has a region that overlaps with conductor 542a or conductor 542b. It does not have. As a result, a shape is formed between the conductor 560 and the conductors 542a and 542b. The resulting parasitic capacitance can be reduced. Therefore, the switching of transistor 500 This allows for increased speed and improved frequency response.

[0164] The conductor 560 may function as the first gate (also called the top gate) electrode. Furthermore, the conductor 503 functions as a second gate (also called a bottom gate) electrode. In some cases, the potential applied to conductor 503 is changed to the potential applied to conductor 560. By changing it independently, without linking it to the other parameters, the Vth of transistor 500 can be controlled. This can be done. In particular, by applying a negative potential to the conductor 503, the transistor 500 By making Vth greater than 0V, it becomes possible to reduce the off-current. Therefore, conductivity Applying a negative potential to body 503 is more effective than not applying one to the conductor 560. The drain current when the potential is 0V can be reduced.

[0165] The conductor 503 is positioned to overlap with the oxide 530 and the conductor 560. Therefore, when a potential is applied to the conductor 560 and the conductor 503, the conductor 560 generates The electric field generated by the conductor 503 connects with the electric field generated by the conductor 503, forming a chain in the oxide 530. It can cover the flannel-forming region. In this specification, the first gate electrode and the second The structure of a transistor where the electric field of the gate electrode electrically surrounds the channel formation region. This is called a surrounded channel (S-channel) structure.

[0166] Furthermore, in this specification, the S-channel structure is defined as the source electrode and the drain electrode. The sides and periphery of the oxide 530 in contact with the conductors 542a and 542b, which function as such. The edges have the characteristic of being I-shaped, just like the channel-forming region. Also, conductor 542 The sides and periphery of the oxide 530 in contact with a and the conductor 542b are in contact with the insulator 544. Therefore, it can be type I, similar to the channel-forming region. In this specification, type I This can be treated similarly to high-purity genuine materials, as will be described later. Furthermore, as disclosed in this specification, etc. The S-channel structure is different from the Fin-type and Planar-type structures. By adopting a NEL structure, resistance to short channel effects is increased, or in other words, short channel This allows for the creation of a transistor that is less susceptible to the Nell effect.

[0167] Furthermore, the conductor 503 has the same configuration as the conductor 518, and the insulators 514 and 5 A conductor 503a is formed in contact with the inner wall of the 16 openings, and a conductor 503b is formed further inside. It has been done.

[0168] Insulators 520, 522, 524, and 550 are used as gate insulating films. It has the function of being functional.

[0169] Here, the insulator 524 in contact with the oxide 530 is more than the oxygen that satisfies the stoichiometric composition. It is preferable to use an insulator containing oxygen. In other words, the insulator 524 contains excess oxygen. It is preferable that such an insulator containing excess oxygen is brought into contact with oxide 530. By providing this, oxygen deficiency in the oxide 530 is reduced, and the reliability of the transistor 500 is improved. It can improve sexual performance.

[0170] As an insulator having an excess oxygen region, specifically, an oxidative material in which some oxygen is removed by heating. It is preferable to use a material. Oxides that desorb oxygen upon heating include TDS (The In rmal desorption spectroscopy analysis, oxygen atoms were converted... The calculated amount of oxygen desorption is 1.0 × 10⁻⁶. 18 atoms / cm3 Preferably, it is 1.0× 10 19 atoms / cm 3 Preferably, it is further 2.0×10 19 atoms / cm 3 Preferably, it is 3.0×10 20 atoms / cm 3 or more, and it is an oxide film. Note that The surface temperature of the film during the above TDS analysis is preferably in the range of 100°C or higher and 700°C or lower, or 10 0°C or higher and 400°C or lower.

[0171] Also, when the insulator 524 has an excess oxygen region, the insulator 522 preferably has a function of suppressing the diffusion of oxygen (for example, oxygen atoms, oxygen molecules, etc.) (it is difficult for the above oxygen to permeate). It is preferable that

[0172] Since the insulator 522 has a function of suppressing the diffusion of oxygen and impurities, the oxygen possessed by the oxide 53 0 does not diffuse to the insulator 520 side, which is preferable. Also, the conductor 503 can be prevented from reacting with the oxygen possessed by the insulator 524 and the oxide 530.

[0173] The insulator 522 is preferably a single layer or a laminate of an insulator containing a so-called high-k material such as aluminum oxide, hafnium oxide, tantalum oxide, zirconium oxide, lead zirconate titanate (PZT), strontium titanate (SrTiO3) or (Ba,Sr)TiO3 (BST). As the miniaturization and high integration of transistors progress problems such as leakage current may occur due to the thinning of the gate insulating film. By using a high-k material for the insulator that functions as the gate insulating film, it is possible to reduce the gate potential during transistor operation while maintaining the physical film thickness. ​​​​

[0174] In particular, it has the function of suppressing the diffusion of impurities and oxygen (the above oxygen is less permeable). ) Insulators containing oxides of aluminum and hafnium, or both, which are insulating materials. It is best to use a body. An insulating material containing an oxide of either or both aluminum and hafnium. As a body, aluminum oxide, hafnium oxide, aluminum and hafnium-containing acids It is preferable to use alloys (hafnium aluminate, etc.). When an insulator 522 is formed, the insulator 522 prevents the release of oxygen from the oxide 530 and tra As a layer to suppress the incorporation of impurities such as hydrogen from the peripheral area of ​​the radiator 500 into the oxide 530 It works.

[0175] Alternatively, these insulators may contain, for example, aluminum oxide, bismuth oxide, germanium oxide. M, niobium oxide, silicon oxide, titanium oxide, tungsten oxide, yttrium oxide, acid Zirconium oxide may be added. Alternatively, these insulators may be nitrided. Silicon oxide, silicon oxide-nitride, or silicon nitride may be used as an insulator in a laminated form.

[0176] Furthermore, it is preferable that the insulator 520 is thermally stable. For example, silicon oxide and Silicon oxide nitride is suitable because it is thermally stable. Also, high-k material By combining the insulator with silicon oxide or silicon oxide nitride, thermal stability and A laminated insulator 520 with a high dielectric constant can be obtained.

[0177] Furthermore, the insulators 520, 522, and 524 have a laminated structure of two or more layers. It is also acceptable to have a laminated structure made of the same material, or a structure made of different materials. A layered structure is also acceptable.

[0178] The transistor 500 is formed in the oxide 530 including the channel formation region as an oxide semiconductor. It is preferable to use a metal oxide that can perform the function. For example, as oxide 530, In-MZ n oxide (element M is aluminum, gallium, yttrium, copper, vanadium, beryllium) Um, boron, titanium, iron, nickel, germanium, zirconium, molybdenum, rancid Tan, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium It is preferable to use one or more metal oxides selected from the above. Also, oxide 5 For 30, In-Ga oxide or In-Zn oxide may be used.

[0179] Furthermore, it is preferable to use a metal oxide with a low carrier density for the transistor 500. When lowering the carrier density of the metal oxide, the concentration of impurities in the metal oxide is reduced. Therefore, it is sufficient to lower the defect level density. In this specification, the impurity concentration is low and the defect level A low ion density is referred to as high-purity intrinsic or substantially high-purity intrinsic. Examples of impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, and nickel. , silicone, etc.

[0180] In particular, the hydrogen contained in metal oxides reacts with the oxygen bonded to the metal atoms to form water, Oxygen vacancies can form in metal oxides. If defects are present, the transistor may exhibit normally-on characteristics. Furthermore, A defect where hydrogen fills an oxygen vacancy functions as a donor, generating electrons, which act as carriers. Furthermore, some of the hydrogen combines with the metal atom, and oxygen combines with the electron carrier. This can generate transients. Therefore, transients using metal oxides that contain a lot of hydrogen are produced. Ta tends to exhibit normally-on characteristics.

[0181] Defects where hydrogen fills an oxygen vacancy can function as donors for metal oxides. However, It is difficult to quantitatively evaluate the defect in question. Therefore, in metal oxides, donor In some cases, the evaluation is based on carrier density rather than concentration. Therefore, in this specification, metal acids The parameters of the compound are not the donor concentration, but rather the assumption that no electric field is applied. Rear density may be used. In other words, the "carrier density" as described herein, etc., refers to "donor It can sometimes be rephrased as "concentration."

[0182] Therefore, when using metal oxides in oxide 530, the amount of hydrogen in the metal oxide should be reduced as much as possible. It is preferable that this is done. Specifically, in metal oxides, secondary ion mass spectrometry ( SIMS (Secondary Ion Mass Spectrometry) The hydrogen concentration obtained is 1 × 10 20 atoms / cm 3 Less than 1 × 10 19 a toms / cm 3 Less than 5x10 18 atoms / cm 3 Less than, even better Mashiku is 1 x 10 18 atoms / cm 3 It shall be less than. Impurities such as hydrogen shall be sufficiently reduced. By using a metal oxide in the channel formation region of a transistor, stable electrical characteristics can be achieved. It can be granted.

[0183] Furthermore, when a metal oxide is used for oxide 530, the metal oxide carrier in the channel formation region The density is 1 × 10⁻⁶ 18 cm -3 The following is preferable: 1 × 10 17 cm -3 less than It is more preferable that it be 1 × 10 16 cm -3 It is even more preferable that it be less than 1 ×10 13 cm -3 It is even more preferable that it be less than 1 × 10 12 cm -3 Less than It is even more preferable that the lower limit of the carrier density of the metal oxide in the channel formation region is Therefore, there are no particular limitations, but for example, 1 x 10 -9 cm -3 It can be done this way.

[0184] Furthermore, when a metal oxide is used for oxide 530, the conductor 542 (conductor 542a, and When the conductor 542b) and the oxide 530 come into contact, the oxygen in the oxide 530 enters the conductor 54 It may diffuse into 2, causing the conductor 542 to oxidize. When the conductor 542 oxidizes, the conductivity There is a high probability that the conductivity of body 542 will decrease. Note that oxygen in oxide 530 is present in conductor 542. To describe the diffusion into the oxide 530, it can be rephrased as the conductor 542 absorbing oxygen from the oxide 530. It is possible.

[0185] Furthermore, the oxygen in oxide 530 is conductor 542 (conductor 542a and conductor 542b) By diffusion, the conductor 542a and oxide 530b, and the conductor 542b and A different layer may be formed between the oxide 530b and the conductor 542. Because it contains a large amount of oxygen, this different layer is presumed to have insulating properties. At this time, conductor 542 The three-layer structure of the aforementioned heterogeneous layer and oxide 530b is a three-layer structure consisting of metal-insulator-semiconductor. It can be considered a structure, and MIS (Metal-Insulator-Semiconductor) It is sometimes called a ctor structure, or a diode junction structure mainly consisting of an MIS structure. ru.

[0186] Furthermore, the above-mentioned heterogeneous layer is not limited to being formed between the conductor 542 and the oxide 530b. For example, when a different layer is formed between the conductor 542 and the oxide 530c, or when the conductor 54 The fields formed between 2 and oxide 530b, and between conductor 542 and oxide 530c There is a match.

[0187] Furthermore, the metal oxide that functions as a channel-forming region in oxide 530 is bandgable It is preferable to use a device with a voltage of 2 eV or higher, preferably 2.5 eV or higher. By using a metal oxide with a large band gap, the off-current of the transistor can be reduced. It is possible.

[0188] Oxide 530 has oxide 530a beneath oxide 530b, so oxide 530a Furthermore, it is possible to suppress the diffusion of impurities from the structure formed below to oxide 530b. It can be done. Also, by having oxide 530c on oxide 530b, oxide 530c is better than The diffusion of impurities from the structure formed above to oxide 530b can be suppressed. .

[0189] Furthermore, oxide 530 has a layered structure of multiple oxide layers with different atomic ratios of each metal atom. It is preferable that the metal oxide used in oxide 530a contains constituent elements The atomic ratio of element M in the oxide is the element of the constituent elements in the metal oxide used in oxide 530b. It is preferable that the ratio is greater than the atomic ratio of element M. Also, the metal oxide used in oxide 530a In this case, the atomic ratio of element M to In is in the metal oxide used in oxide 530b. Furthermore, it is preferable that the atomic ratio of element M to In is greater than that of In. Also, in oxide 530b In the metal oxide used, the atomic ratio of In to element M is used in oxide 530a. It is preferable that the atomic ratio of In to element M in the metal oxide is greater than that of In. Oxide 530c is a metal oxide that can be used in oxide 530a or oxide 530b. The object can be used.

[0190] Furthermore, the energy at the lower end of the conduction band of oxide 530a and oxide 530c is It is preferable that the energy of b is higher than the energy of the lower end of the conduction band. In other words, oxide The electron affinity of 530a and oxide 530c is smaller than the electron affinity of oxide 530b. It is preferable.

[0191] Here, at the joint of oxide 530a, oxide 530b, and oxide 530c, The energy levels at the lower end of the guide band change smoothly. In other words, oxide 530a, oxide The energy levels at the lower end of the conduction band at the junction of 530b and oxide 530c are continuous. It can also be said that it undergoes a gradual change or continuous bonding. In order to do this, oxide 5 At the interface between 30a and oxide 530b, and at the interface between oxide 530b and oxide 530c It is desirable to lower the defect level density of the mixed layer that is formed.

[0192] Specifically, oxide 530a and oxide 530b, and oxide 530b and oxide 530c, By having a common element other than the primary element (as the main component), a mixed layer with a low defect level density is formed. It is possible. For example, if oxide 530b is In-Ga-Zn oxide, then oxide 5 As 30a and oxide 530c, In-Ga-Zn oxide, Ga-Zn oxide, oxide Gallium or similar materials would be suitable.

[0193] In this case, the main carrier pathway is oxide 530b. Oxide 530a, oxide 53 By configuring 0c as described above, the interface between oxide 530a and oxide 530b, and oxidation The defect level density at the interface between material 530b and oxide 530c can be reduced. Therefore, the influence of interfacial scattering on carrier conduction is reduced, and transistor 500 has high On-current can be obtained.

[0194] On the oxide 530b, there is a conductor 542 that functions as a source electrode and a drain electrode. Conductors 542a and 542b are provided. As for the conductor 542, aluminum nium, chromium, copper, silver, gold, platinum, tantalum, nickel, titanium, molybdenum, tung Stainless steel, hafnium, vanadium, niobium, manganese, magnesium, zirconium, be Selected from lylium, indium, ruthenium, iridium, strontium, and lanthanum. A metal element, or an alloy containing the above-mentioned metal elements, or a combination of the above-mentioned metal elements It is preferable to use alloys such as tantalum nitride, titanium nitride, and tungsten. , nitrides containing titanium and aluminum, nitrides containing tantalum and aluminum, lutein oxide nium, ruthenium nitride, oxides containing strontium and ruthenium, lanthanum and nickel It is preferable to use oxides containing tar. Also, tantalum nitride, titanium nitride, titanium Nitrides containing aluminum, nitrides containing tantalum and aluminum, ruthenium oxide, Ruthenium nitride, oxides containing strontium and ruthenium, and oxides containing lanthanum and nickel. Oxides are conductive materials that are resistant to oxidation, or materials that maintain their conductivity even when absorbing oxygen. Therefore, it is preferable.

[0195] Furthermore, as shown in Figure 8A, at the interface of oxide 530 with conductor 542 and in its vicinity, low In the case where region 543 (region 543a and region 543b) is formed as a resistive region, Yes. In this case, region 543a functions as either the source region or the drain region, Region 543b functions as either the source region or the drain region. Also, region 543a A channel-forming region is formed in the region sandwiched between region 543b.

[0196] By providing the conductor 542 in contact with the oxide 530, the oxygen concentration in region 543 It may be reduced. Also, in region 543, the metal contained in the conductor 542 and the oxide 530 A metal compound layer containing the components may be formed. In such cases, region 543 As the carrier density increases, region 543 becomes a low-resistance region.

[0197] The insulator 544 is provided so as to cover the conductor 542, thereby suppressing oxidation of the conductor 542. At this time, the insulator 544 covers the side surface of the oxide 530 and is arranged to be in contact with the insulator 524. I don't mind being kicked.

[0198] Insulator 544 includes hafnium, aluminum, gallium, yttrium, and zirconium. Tungsten, titanium, tantalum, nickel, germanium, or magnesium One or more metal oxides selected from the above can be used.

[0199] In particular, as insulator 544, an oxide of either aluminum or hafnium, or both. Insulators containing aluminum oxide, hafnium oxide, aluminum and hafnium It is preferable to use an oxide containing um (hafnium aluminate), etc. In particular, hafnium Um aluminate has higher heat resistance than hafnium oxide film. Therefore, in subsequent processes... It is preferable because it does not crystallize easily during heat treatment. Furthermore, the conductor 542 has oxidation resistance. If the material does not experience a significant decrease in conductivity even when absorbing oxygen, the insulator 544 is essential. This is not the correct configuration. The design should be adjusted as needed based on the desired transistor characteristics.

[0200] Insulator 550 functions as a gate insulating film. Insulator 550 is inside oxide 530c. It is preferable to place it in contact with the (top and side) surfaces. The insulator 550 is heated by oxygen It is preferable to form it using an insulator that emits oxygen. For example, in TDS analysis, oxygen The amount of oxygen removed in terms of offspring is 1.0 × 10⁻⁶. 18 atoms / cm 3 Preferably 1 .0 × 10 19 atoms / cm 3 More preferably 2.0 × 10 19 atoms / cm 3 Above, or 3.0 × 10 20 atoms / cm 3 The above describes the oxide film. The surface temperature of the film during the above TDS analysis is in the range of 100°C to 700°C. It is preferable.

[0201] Specifically, silicon oxide, silicon oxide nitride, silicon nitride oxide, and silicon oxide containing excess oxygen. Silicon oxide, fluorinated silicon oxide, carbon-added silicon oxide, carbon and Nitrogen-added silicon oxide and porous silicon oxide can be used. In particular, Silicon oxide and silicon oxide-nitride are preferred because they are stable to heat.

[0202] An insulator that releases oxygen upon heating is designated as insulator 550 and is brought into contact with the upper surface of oxide 530c. By providing this, the oxide 530b is transmitted from the insulator 550 through the oxide 530c. It can effectively supply oxygen to the channel-forming region. Also, similar to insulator 524. Preferably, the concentration of impurities such as water or hydrogen in the insulator 550 is reduced. The thickness of the edge body 550 is preferably between 1 nm and 20 nm.

[0203] Furthermore, in order to efficiently supply excess oxygen from the insulator 550 to the oxide 530, A metal oxide may be provided between the body 550 and the conductor 560. The metal oxide is an insulator. It is preferable to suppress oxygen diffusion from 550 to the conductor 560. By providing a metal oxide, the diffusion of excess oxygen from the insulator 550 to the conductor 560 is suppressed. This means that the decrease in the amount of excess oxygen supplied to oxide 530 can be suppressed. This can suppress the oxidation of the conductor 560 due to excess oxygen. The metal oxide in question is Any material suitable for use as an insulator 544 may be used.

[0204] The conductor 560, which functions as the first gate electrode, is shown as a two-layer structure in Figures 8A and 8B. However, it may be a single-layer structure or a laminated structure of three or more layers.

[0205] Conductor 560a contains hydrogen atoms, hydrogen molecules, water molecules, nitrogen atoms, nitrogen molecules, and nitrogen oxide molecules. Conductive properties that suppress the diffusion of impurities such as N2O, NO, NO2, and copper atoms. It is preferable to use a material. Alternatively, oxygen (for example, oxygen atoms, oxygen molecules, etc.) It is preferable to use a conductive material that has the function of suppressing the diffusion of (one of) the conductive material. Conductor 5 Because 60a has the function of suppressing oxygen diffusion, the oxygen contained in the insulator 550 This suppresses the oxidation of the conductor 560b and the resulting decrease in conductivity. Examples of conductive materials that have the function of suppressing dispersion include tantalum, tantalum nitride, and luteinizing agent. It is preferable to use nium or ruthenium oxide.

[0206] Furthermore, since conductor 560b also functions as wiring, a highly conductive material should be used. A conductive material mainly composed of tungsten, copper, or aluminum is preferred. It can be used. Also, the conductor 560b may be in a laminated structure, for example, titanium. Alternatively, a laminated structure of titanium nitride and the above-mentioned conductive material may be used.

[0207] The insulator 580 is provided on the conductor 542 via the insulator 544. It is preferable to have an excess oxygen region. For example, as the insulator 580, silicon oxide, Silicon oxide nitride, silicon nitride, silicon nitride, fluorine-added silicon oxide, Carbon-doped silicon oxide, carbon and nitrogen-doped silicon oxide, porous acids It is preferable to have silicon oxide or resin. In particular, silicon oxide and nitrile oxide Silicon oxides are preferred because they are thermally stable. In particular, silicon oxide and porous silicon oxides are preferred. Silicon is preferred because it can easily form an excess oxygen region in a later process.

[0208] The insulator 580 preferably has an excess oxygen region. By providing the edge 580 in contact with the oxide 530c, the oxygen in the insulator 580 is removed from the oxide. It can be efficiently supplied to oxide 530 through 530c. Note that insulator 58 It is preferable that the concentration of impurities such as water or hydrogen in the solution is reduced.

[0209] The opening in the insulator 580 is formed superimposed on the region between the conductor 542a and the conductor 542b. As a result, the conductor 560 has an opening in the insulator 580, and the conductor 542a and the conductor It is formed in a way that it is embedded in the region sandwiched between 542b.

[0210] When miniaturizing semiconductor devices, it is necessary to shorten the gate length, but the conductor 56 It is necessary to prevent the conductivity of 0 from decreasing. To achieve this, the film thickness of conductor 560 is increased. As a result, the conductor 560 may have a shape with a high aspect ratio. In this embodiment, the conductor Since 560 is to be embedded in the opening of the insulator 580, the conductor 560 has an aspect ratio Even with a highly shaped form, the conductive material 560 can be formed without collapsing during the process. ru.

[0211] The insulator 574 is located on the upper surface of the insulator 580, the upper surface of the conductor 560, and the upper surface of the insulator 550. It is preferable that it be provided in contact with the insulator 574. This allows for the creation of excess oxygen regions in the insulators 550 and 580. Oxygen can be supplied to the oxide 530 from the excess oxygen region.

[0212] For example, as insulator 574, hafnium, aluminum, gallium, yttrium, and Titanium, tungsten, titanium, tantalum, nickel, germanium, or magnesium Metal oxides containing one or more selected metals, such as cium, can be used. ru.

[0213] In particular, aluminum oxide has high barrier properties, and in thin films of 0.5 nm to 3.0 nm... However, the diffusion of hydrogen and nitrogen can be suppressed. Therefore, the sputtering method The aluminum oxide film formed using this method serves as both an oxygen source and a barrier against impurities such as hydrogen. It can also function as a membrane.

[0214] Furthermore, it is preferable to provide an insulator 581 that functions as an interlayer film on top of the insulator 574. Insulator 581, like insulator 524, has an impurity concentration of water or hydrogen in the film. It is preferable that it be reduced.

[0215] Furthermore, openings formed in insulators 581, 574, 580, and 544 Conductors 540a and 540b are placed in the opening. 40b is provided opposite the conductor 560, with the conductor 540a and conductor 540b in between. This has the same configuration as conductors 546 and 548, which will be described later.

[0216] An insulator 582 is provided on the insulator 581. The insulator 582 is resistant to oxygen and hydrogen. Therefore, it is preferable to use a barrier material. The same material as body 514 can be used. For example, insulator 582 can be made of aluminum oxide. It is preferable to use metal oxides such as um, hafnium oxide, and tantalum oxide.

[0217] In particular, aluminum oxide is a source of oxygen and hydrogen, which can cause variations in the electrical properties of transistors. It has a high barrier effect that prevents both water and other impurities from passing through the film. Aluminum oxide is susceptible to hydrogen, moisture, and other elements during and after the transistor fabrication process. This prevents impurities from entering transistor 500. This can suppress the release of oxygen from the oxides that make up the transistor. It is suitable for use as a protective film against 500.

[0218] Furthermore, an insulator 586 is provided on the insulator 582. The insulator 586 is insulator 3 The same materials as in 20 can be used. Additionally, a material with a relatively low dielectric constant can be used as the interlayer film. This reduces parasitic capacitance between wires. For example, as insulator 586 Silicon oxide films and silicon oxide nitride films can be used.

[0219] Also, insulator 520, insulator 522, insulator 524, insulator 544, insulator 580, insulation Body 574, insulator 581, insulator 582, and insulator 586 are connected to conductor 546, and Conductors such as 548 are embedded within.

[0220] Conductors 546 and 548 are connected to the capacitive element 600, the transistor 500, or It functions as a plug or wiring to connect to the Rangista 300. Conductor 546, The conductor 548 is provided using the same material as the conductors 328 and 330. It is possible.

[0221] Next, a capacitive element 600 is provided above the transistor 500. 00 comprises a conductor 610, a conductor 620, and an insulator 630.

[0222] Furthermore, a conductor 612 may be provided on the conductor 546 and the conductor 548. Conductor 6 12 functions as a plug or wire connecting to transistor 500. Conductive Body 610 functions as an electrode for the capacitive element 600. Note that the conductor 612 and The conductor 610 can be formed simultaneously.

[0223] Conductors 612 and 610 contain molybdenum, titanium, tantalum, and tungsten. A metal film containing elements selected from aluminum, copper, chromium, neodymium, and scandium. Alternatively, metal nitride films containing the above-mentioned elements (tantalum nitride film, titanium nitride film, monoxide nitride film) A ribdenum film, tungsten nitride film, etc., can be used. Alternatively, indium tin oxide can be used. Indium oxide containing tungsten oxide, indium zinc containing tungsten oxide Oxides, indium oxide containing titanium oxide, indium tin oxide containing titanium oxide, Conductive materials such as indium zinc oxide and indium tin oxide with added silicon oxide are applied. It is also possible.

[0224] In Figure 7, the conductors 612 and 610 are shown as single-layer structures, but the configuration It is not limited to this, and may also be a laminated structure of two or more layers. For example, a conductor with barrier properties and a conductive A conductor with barrier properties between it and a highly conductive conductor, and a conductor that is tightly packed against a highly conductive conductor. A conductive material with high adhesion properties may be formed.

[0225] A conductor 620 is provided so as to overlap with the conductor 610 via an insulator 630. The conductor 620 uses a conductive material such as a metallic material, an alloy material, or a metal oxide material. This is possible. High-melting-point materials such as tungsten and molybdenum that offer both heat resistance and conductivity. It is preferable to use a conductor, and it is particularly preferable to use tungsten. When forming it simultaneously with other structures, low-resistance metallic materials such as Cu (copper) or Al (aluminium) are used. You can use (Mu), etc.

[0226] An insulator 650 is provided on the conductor 620 and the insulator 630. 0 can be provided using the same material as insulator 320. Also, insulator 650 is It may also function as a flattening film that covers the uneven surface below it.

[0227] By using this structure, in semiconductor devices using transistors having oxide semiconductors This can suppress fluctuations in electrical characteristics and improve reliability. Or, on A transistor having an oxide semiconductor with a high current can be provided. Or, off It is possible to provide a transistor having an oxide semiconductor with a low current. Or, A semiconductor device with reduced power consumption can be provided. Alternatively, a device having an oxide semiconductor can be provided. In semiconductor devices using transistors, miniaturization or high integration can be achieved.

[0228] <Example of transistor structure> The transistor 500 of the semiconductor device shown in this embodiment is not limited to the above structure. No. Below, we will describe some structural examples that can be used in transistor 500.

[0229] <Example of transistor structure 1> The structure of transistor 510A is illustrated using Figures 9A, 9B, and 9C. Figure 9A This is a top view of transistor 510A. Figure 9B shows the same view as in Figure 9A, indicated by the dashed line L1-L2. This is a cross-sectional view of the area. Figure 9C is a cross-sectional view of the area indicated by the dashed line W1-W2 in Figure 9A. Note that in the top view of Figure 9A, some elements have been omitted for clarity.

[0230] Figures 9A, 9B, and 9C show transistor 510A and an insulating film that functions as an interlayer. Body 511, insulator 512, insulator 514, insulator 516, insulator 580, insulator 582, And insulator 584 is shown. Also electrically connected to transistor 510A, Conductors 546 (conductors 546a and 546b) that function as tact plugs and This shows a conductor 503 that functions as wiring.

[0231] Transistor 510A has a conductor 560 that functions as the first gate electrode (conductor 560 a) and conductor 560b), and conductor 505 (conductor) which functions as a second gate electrode. 505a, and conductor 505b), and insulator 550 which functions as the first gate insulating film And, insulators 521, 522, and 52, which function as a second gate insulating film. 4 and an oxide 530 (oxide 530a, oxide 530a) having a region in which a channel is formed b) and oxide 530c), and a conductor 54 that functions as either a source or a drain. 2a, a conductor 542b that functions as the other of source or drain, and an insulator 574 It holds.

[0232] Furthermore, in the transistor 510A shown in Figure 9, oxide 530c, insulator 550, and conductive The electric body 560 is positioned within an opening provided in the insulator 580, via the insulator 574. Furthermore, oxide 530c, insulator 550, and conductor 560 are conductor 542a, and It is placed between the conductive material 542b.

[0233] Insulators 511 and 512 function as interlayer films.

[0234] The interlayer films include silicon oxide, silicon oxide nitride, silicon nitride oxide, and aluminum oxide. Hafnium oxide, tantalum oxide, zirconium oxide, lead zirconate titanate (PZT ), strontium titanate (SrTiO3) or (Ba,Sr)TiO3 (BST) Insulators such as these can be used in single or multilayer configurations. Alternatively, these insulators can be, for example, Aluminum oxide, bismuth oxide, germanium oxide, niobium oxide, silicon oxide, acid Titanium oxide, tungsten oxide, yttrium oxide, and zirconium oxide may be added. Alternatively, these insulators may be subjected to nitridation treatment. The above insulators may be subjected to silicon oxide, silicon oxide nitride, and silicon oxide nitride. Recon or silicon nitride may be used in a laminated form.

[0235] For example, insulator 511 allows impurities such as water or hydrogen to enter transistor 510 from the substrate side. It is preferable that it functions as a barrier film to suppress contamination of A. Therefore, an insulator 511 has the function of suppressing the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, and copper atoms. It is preferable to use an insulating material that does not easily allow the above impurities to permeate. Alternatively, oxygen ( For example, it has the function of suppressing the diffusion of at least one of the following: an oxygen atom, an oxygen molecule, etc. (above) It is preferable to use an insulating material (which is less permeable to oxygen). Also, for example, insulator 51 Aluminum oxide or silicon nitride may be used as component 1. With this configuration, hydrogen, Impurities such as water diffuse from the substrate side to the transistor 510A side, rather than from the insulator 511. It can be suppressed.

[0236] For example, it is preferable that the dielectric constant of the insulator 512 is lower than that of the insulator 511. By using a suitable material as the interlayer film, parasitic capacitance between wiring can be reduced.

[0237] The conductor 503 is formed to be embedded in the insulator 512. The height of the top surface of the conductor and the height of the top surface of the insulator 512 can be made to be approximately the same. While the present invention describes a layered configuration, it is not limited thereto. For example, The conductive element 503 may have a multilayer film structure of two or more layers. It is preferable to use a highly conductive material whose main component is copper or aluminum. stomach.

[0238] In transistor 510A, the conductor 560 is the first gate (also known as the top gate) (u) It may function as an electrode. Also, the conductor 505 is the second gate (bottom gate). It may function as an electrode (also called a toe). In that case, the potential applied to the conductor 505 By changing this independently of the potential applied to the conductor 560, the transient The threshold voltage of the 510A can be controlled. In particular, a negative potential can be applied to the conductor 505. By adding this, the threshold voltage of transistor 510A is made greater than 0V, and the off-current This makes it possible to reduce the amount of conductor 505. Therefore, applying a negative potential to the conductor 505 is preferable. The drain current when the potential applied to the conductor 560 is 0V is smaller than when no potential is applied. It can be done.

[0239] Furthermore, for example, by superimposing the conductor 505 and the conductor 560, the conductor 560 , and when a potential is applied to the conductor 505, the electric field generated from the conductor 560 and the conductor 5 The electric field generated from 05 connects with and covers the channel formation region formed in the oxide 530. It is possible.

[0240] In other words, the electric field of the conductor 560 which functions as the first gate electrode, and the second gate electric field The electric field of the conductor 505, which functions as a pole, electrically isolates the channel formation region. It can be surrounded. That is, similar to transistor 500 described earlier, surround It has a ded channel (S-channel) structure.

[0241] Insulators 514 and 516, like insulator 511 or insulator 512, are interlayer It functions as a film. For example, insulator 514 allows impurities such as water or hydrogen to enter from the substrate side. It is preferable that it functions as a barrier film to suppress contamination of transistor 510A. With this configuration, impurities such as hydrogen and water can enter the transistor 5 from the substrate side rather than from the insulator 514. This can suppress diffusion to the 10A side. Also, for example, insulator 516 is an insulator A dielectric constant lower than 514 is preferable. By using a material with a low dielectric constant as the interlayer film, This can reduce the parasitic capacitance that occurs between lines.

[0242] The conductor 505, which functions as a second gate, is located at the openings of the insulators 514 and 516. A conductor 505a is formed in contact with the inner wall, and a conductor 505b is formed further inside. Here, the height of the upper surfaces of the conductors 505a and 505b and the upper surface of the insulator 516 The height can be made to be about the same. Note that in transistor 510A, the conductor 505a and the conductor Although the present invention describes a configuration in which 505b is stacked, the present invention is not limited thereto. For example, the conductor 505 may be provided as a single layer or as a laminated structure of three or more layers. stomach.

[0243] Here, the conductor 505a allows for the diffusion of impurities such as hydrogen atoms, hydrogen molecules, water molecules, and copper atoms. It is preferable to use a conductive material that has a suppressive function (i.e., one that does not easily allow the above-mentioned impurities to pass through). Alternatively, inhibit the diffusion of oxygen (e.g., at least one oxygen atom, oxygen molecule, etc.). It is preferable to use a conductive material that has a function (that is impermeable to the above-mentioned oxygen). In the specification, the function of suppressing the diffusion of impurities or oxygen means the above impurities or above The function is to suppress the diffusion of any one or all of the specified oxygen molecules.

[0244] For example, conductor 505a has the function of suppressing oxygen diffusion, so conductor 505b This can suppress the oxidation that causes a decrease in conductivity.

[0245] Furthermore, if the conductor 505 also functions as wiring, the conductor 505b may be tungsten, copper, Alternatively, it is preferable to use a highly conductive material, mainly composed of aluminum. In that case, the conductor 503 does not necessarily have to be provided. Note that the conductor 505b is a single layer. As shown in the illustration, a laminated structure is also possible, for example, titanium or titanium nitride and the above conductive material. It may also be used as a laminate.

[0246] Insulators 521, 522, and 524 function as a second gate insulating film. It holds.

[0247] Furthermore, it is preferable that the insulator 522 has barrier properties. This prevents impurities such as hydrogen from entering the transistor 510A from its peripheral area. It functions as a layer that prevents contamination.

[0248] Insulator 522 is, for example, aluminum oxide, hafnium oxide, aluminum and haf Oxides containing nium (hafnium aluminate), tantalum oxide, zirconium oxide, Lead zirconate tane (PZT), strontium titanate (SrTiO3), or (Ba Insulators containing so-called high-k materials such as ,Sr)TiO3(BST) in a single layer or It is preferable to use them in a stacked configuration. As transistors become smaller and more integrated, the gate Thinning the insulating film can sometimes lead to problems such as leakage current. By using high-k material as a functional insulator, the physical film thickness is maintained while the transient This allows for a reduction in gate potential during operation.

[0249] Furthermore, it is preferable that the insulator 521 is thermally stable. For example, silicon oxide and Silicon oxide nitride is suitable because it is thermally stable. Also, high-k material By combining the insulator with silicon oxide or silicon oxide nitride, thermal stability and A laminated insulator 521 with a high dielectric constant can be obtained.

[0250] Note that Figure 9 shows a three-layer stacked structure as the second gate insulating film, but a single layer or A laminated structure of two or more layers is also acceptable. In that case, it is not limited to a laminated structure made of the same material, A laminated structure made of different materials is also acceptable.

[0251] Oxide 530 having a region that functions as a channel-forming region is oxide 530a and It has an oxide 530b on substance 530a and an oxide 530c on oxide 530b. Because oxide 530a is present below oxide 530b, it is formed below oxide 530a. This can suppress the diffusion of impurities from the structure to oxide 530b. Having oxide 530c on 530b, the structure formed above oxide 530c The diffusion of impurities from the material to oxide 530b can be suppressed. Therefore, an oxide semiconductor, which is a type of metal oxide as described above, can be used.

[0252] Furthermore, the oxide 530c enters the opening provided in the insulator 580 via the insulator 574. It is preferable that it be provided. If the insulator 574 has barrier properties, from the insulator 580 This can suppress the diffusion of impurities into oxide 530.

[0253] The conductor 542 functions as a source electrode on one end and a drain electrode on the other.

[0254] Conductors 542a and 542b are aluminum, titanium, chromium, nickel, and copper. , yttrium, zirconium, molybdenum, silver, tantalum, or tungsten, etc. Metals or alloys with metals as the main component can be used. In particular, tantalum nitride and others Metal nitride films have barrier properties against hydrogen or oxygen, and also have high oxidation resistance, preferable.

[0255] Furthermore, although Figure 9 shows the case where the conductor 542 has a single-layer structure, a stacked structure of two or more layers can also be used. This may also be done. For example, a tantalum nitride film and a tungsten film can be laminated. Alternatively, a titanium film may be used. An aluminum film may be laminated on top of the tungsten film. A two-layer structure, a two-layer structure in which a copper film is laminated on a copper-magnesium-aluminum alloy film, titanium This can also be expressed as a two-layer structure with a copper film laminated on a tungsten film, or a two-layer structure with a copper film laminated on a tungsten film. good.

[0256] Furthermore, a titanium film or titanium nitride film, and an aluminum film layered on top of the titanium film or titanium nitride film. A titanium film or copper film is laminated, and then a titanium film or titanium nitride film is formed on top of it. Three-layer structure, molybdenum film or molybdenum nitride film, and the molybdenum film or molybdenum nitride An aluminum film or copper film is laminated on top of the molybdenum film, and then a molybdenum film is placed on top of that. It has a three-layer structure that forms a molybdenum nitride film, etc. Furthermore, indium oxide, tin oxide or A transparent conductive material containing zinc oxide may also be used.

[0257] Furthermore, a barrier layer may be provided on the conductor 542. The barrier layer is resistant to oxygen or hydrogen. It is preferable to use a material that has barrier properties. With this configuration, the insulator 574 is formed This can suppress the oxidation of the conductor 542 during film formation.

[0258] For example, metal oxides can be used for the barrier layer. In particular, aluminum oxide, acid Insulating films that provide barriers to oxygen and hydrogen, such as hafnium oxide and gallium oxide, are used. This is preferable. Alternatively, silicon nitride formed by the CVD method may be used.

[0259] Having a barrier layer broadens the range of material choices for the conductor 542. For example, Conductor 542 has low oxidation resistance but high conductivity, such as tungsten and aluminum. Any material can be used. Also, for example, a conductive material that is easy to deposit or process can be used. It is possible.

[0260] Insulator 550 functions as the first gate insulating film. Insulator 550 is connected to insulator 580. The provided opening is provided via oxide 530c and insulator 574. preferable.

[0261] As transistors become smaller and more integrated, the gate insulating film becomes thinner, leading to leakage Problems such as current may occur. In that case, the insulator 550 and the second gate insulating film Similarly, a laminated structure may be used. The insulator that functions as the gate insulating film is made of a high-k material. By creating a laminated structure of a material and a thermally stable material, the physical film thickness is maintained while preventing traction. This allows for a reduction in gate potential during inverter operation. Furthermore, it offers thermal stability and a high dielectric constant. It can be made into a layered structure.

[0262] The conductor 560, which functions as the first gate electrode, is composed of conductor 560a and conductor 560 Conductor 560b is located on a. Conductor 560a, like conductor 505a, has hydrogen atoms Using a conductive material that has the function of suppressing the diffusion of impurities such as hydrogen molecules, water molecules, and copper atoms. It is preferable that oxygen is present. Alternatively, at least one such oxygen (e.g., an oxygen atom, an oxygen molecule, etc.) It is preferable to use a conductive material that has the function of suppressing the diffusion of )

[0263] Because conductor 560a has the function of suppressing oxygen diffusion, the material selection of conductor 560b Selectivity can be improved. In other words, by having the conductor 560a, the conductor 560b This suppresses oxidation and prevents a decrease in conductivity.

[0264] Examples of conductive materials that have the function of suppressing oxygen diffusion include tantalum and tantalum nitride. It is preferable to use ruthenium or ruthenium oxide. Also, conductor 560 As a, an oxide semiconductor that can be used as oxide 530 can be used. In that case, by depositing the conductor 560b using the sputtering method, the electrical properties of the conductor 560a are By reducing its resistance, it can be made into a conductor. This is called OC (Oxide Conduct). This can be called a tor electrode.

[0265] Furthermore, since conductor 560b functions as wiring, it is desirable to use a conductor with high conductivity. Preferred. For example, a conductive material mainly composed of tungsten, copper, or aluminum. It can be used. Furthermore, the conductor 560b may also be in a laminated structure, for example, titanium. Alternatively, a laminate of titanium nitride and the above-mentioned conductive material may be used.

[0266] An insulator 574 is placed between the insulator 580 and the transistor 510A. This refers to an insulating material that has the function of suppressing the diffusion of impurities such as water or hydrogen, and oxygen. It is good to use them. For example, aluminum oxide or hafnium oxide is preferred. It is also, for example, magnesium oxide, gallium oxide, germanium oxide, acid Yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, or tantalum oxide Any metal oxide, silicon nitride, or silicon nitride can be used.

[0267] The presence of the insulator 574 prevents the oxidation of water and other impurities such as hydrogen present in the insulator 580. The diffusion of material 530c to oxide 530b via insulator 550 can be suppressed. It can do so. Furthermore, the excess oxygen present in the insulator 580 suppresses the oxidation of the conductor 560. It is possible.

[0268] Insulators 580, 582, and 584 function as interlayer films.

[0269] Insulator 582, like insulator 514, is designed to prevent impurities such as water or hydrogen from entering from the outside. It is preferable that it functions as a barrier insulating film to suppress contamination of ZISTA 510A.

[0270] Furthermore, insulators 580 and 584, like insulator 516, are more efficient than insulator 582. It is preferable that the dielectric constant is low. By using a material with a low dielectric constant as the interlayer film, the space between the wiring is filled. This can reduce the parasitic capacity.

[0271] Furthermore, transistor 510A is embedded in insulators 580, 582, and 584. It may also be electrically connected to other structures via plugs and wiring such as the embedded conductor 546. stomach.

[0272] Furthermore, the material for the conductor 546 may be a metal material, an alloy material, or a metal, similar to the conductor 505. Using conductive materials such as nitride materials or metal oxide materials in a single layer or in a laminated configuration. This is possible. For example, high-melting-point materials such as tungsten and molybdenum that have both heat resistance and conductivity. It is preferable to use a material. Alternatively, it may be formed from a low-resistance conductive material such as aluminum or copper. It is preferable to do so. Wiring resistance can be reduced by using a low-resistance conductive material.

[0273] For example, conductor 546 is a conductor that has barrier properties against hydrogen and oxygen. By using a laminated structure of tantalum nitride and highly conductive tungsten, the wiring can be It is possible to suppress the diffusion of impurities from the outside while maintaining the conductivity.

[0274] By having the above structure, a transistor with an oxide semiconductor that has a large on-current is used. A semiconductor device can be provided. Alternatively, a device having an oxide semiconductor with a low off-current can be provided. A semiconductor device using a transistor can be provided. Alternatively, variations in electrical characteristics can be suppressed. The aim is to provide a semiconductor device that has stable electrical characteristics and improved reliability. can.

[0275] <Example of transistor structure 2> An example of the structure of transistor 510B is illustrated using Figures 10A, 10B, and 10C. Figure 10A is a top view of transistor 510B. Figure 10B is the same as Figure 10A but with a dashed line L1 -This is a cross-sectional view of the area indicated by L2. Figure 10C shows the area indicated by the dashed line W1-W2 in Figure 10A. This is a cross-sectional view of the position. Note that in the top view of Figure 10A, some elements have been omitted for clarity. This is illustrated in the diagram.

[0276] Transistor 510B is a modified version of transistor 510A. Therefore, the explanation is repeated. To prevent misunderstandings, I will primarily explain the differences between this transistor and the 510A.

[0277] Transistor 510B consists of conductor 542 (conductor 542a and conductor 542b), It has a region in which oxide 530c, insulator 550, and conductor 560 are superimposed. This structure allows for the provision of transistors with high on-current. Furthermore, controllability is also improved. This can provide high-performance transistors.

[0278] The conductor 560, which functions as the first gate electrode, is composed of conductor 560a and conductor 560 Conductor 560b is located on a. Conductor 560a, like conductor 505a, has hydrogen atoms Using a conductive material that has the function of suppressing the diffusion of impurities such as hydrogen molecules, water molecules, and copper atoms. It is preferable that oxygen is present. Alternatively, at least one such oxygen (e.g., an oxygen atom, an oxygen molecule, etc.) It is preferable to use a conductive material that has the function of suppressing the diffusion of )

[0279] Because conductor 560a has the function of suppressing oxygen diffusion, the material selection of conductor 560b Selectivity can be improved. In other words, by having the conductor 560a, the conductor 560b This suppresses oxidation and prevents a decrease in conductivity.

[0280] Also, the top and side surfaces of the conductor 560, the side surfaces of the insulator 550, and the side surfaces of the oxide 530c It is preferable to provide an insulator 574 so as to cover the surface. Note that the insulator 574 is water-resistant. This is achieved by using an insulating material that has the function of suppressing the diffusion of impurities such as hydrogen and oxygen. For example, it is preferable to use aluminum oxide or hafnium oxide. Other examples include magnesium oxide, gallium oxide, germanium oxide, and yttrium oxide. Metal acids such as um, zirconium oxide, lanthanum oxide, neodymium oxide, or tantalum oxide Sodium oxide, silicon nitride, or silicon nitride can be used.

[0281] By providing the insulator 574, oxidation of the conductor 560 can be suppressed. By having body 574, impurities such as water and hydrogen present in the insulator 580 transition This can suppress the diffusion to ST510B.

[0282] Furthermore, between the conductor 546 and the insulator 580, there is an insulator 576 (insulator) that has barrier properties. 576a and insulator 576b) may be provided. By providing insulator 576, To suppress the reaction of oxygen in the edge material 580 with the conductor 546, thereby preventing oxidation of the conductor 546. It is possible.

[0283] Furthermore, by providing a barrier-type insulator 576, the conductor used in plugs and wiring This broadens the range of material selection. For example, the conductor 546 can have the property of absorbing oxygen. On the other hand, by using highly conductive metal materials, low-power semiconductor devices can be provided. This is possible. Specifically, while tungsten and aluminum have low oxidation resistance, Highly conductive materials can be used. Furthermore, for example, conductive materials that are easy to deposit films on or process can be used. An electric body can be used.

[0284] <Example of transistor structure 3> An example of the structure of transistor 510C is illustrated using Figures 11A, 11B, and 11C. Figure 11A is a top view of transistor 510C. Figure 11B is the same as Figure 11A but with a dashed line L1 -This is a cross-sectional view of the area indicated by L2. Figure 11C shows the area indicated by the dashed line W1-W2 in Figure 11A. This is a cross-sectional view of the position. Note that in the top view of Figure 11A, some elements have been omitted for clarity. This is illustrated in the diagram.

[0285] Transistor 510C is a modified version of transistor 510A. Therefore, the explanation is repeated. To prevent misunderstandings, I will primarily explain the differences between this transistor and the 510A.

[0286] The transistor 510C shown in Figure 11 has a conductor 5 between the conductor 542a and the oxide 530b. 47a is positioned, and conductor 547b is positioned between conductor 542b and oxide 530b. Here, conductor 542a (conductor 542b) is conductor 547a (conductor 547b ) extends beyond the upper surface and the side surface on the conductor 560 side, and the area in contact with the upper surface of the oxide 530b It has a region. Here, the conductor 547 is a conductor that can be used in the conductor 542. It is sufficient if the film thickness of the conductor 547 is at least thicker than that of the conductor 542. It's nice.

[0287] The transistor 510C shown in Figure 11 has the above configuration, and therefore the transistor The conductor 542 can be brought closer to the conductor 560 than the sta 510A. Alternatively, The ends of the electric body 542a and the ends of the conductor 542b can be stacked with the conductor 560. This effectively shortens the channel length of the 510C transistor, reducing the on-current and frequency. This allows for improvement of the wavenumber characteristics.

[0288] Furthermore, conductor 547a (conductor 547b) is superimposed on conductor 542a (conductor 542b) It is preferable that it be provided in this manner. With this configuration, the conductor 546a (conductor In etching to form an opening for embedding 546b), conductor 547a (conductor 54 7b) acts as a stopper, preventing oxide 530b from being over-etched. It is possible.

[0289] Furthermore, the transistor 510C shown in Figure 11 is in contact with the insulator 544 and the insulator 545. The arrangement may also be as follows. The insulator 544 may contain impurities such as water or hydrogen, or excess Barrier insulation prevents oxygen from entering transistor 510C from the insulator 580 side. It is preferable that it functions as a film. The insulator 545 is used as the insulator 544. A suitable insulator can be used. For example, aluminum nitride can be used as the insulator 544. Titanium, aluminum nitride, titanium nitride, silicon nitride, or silicon oxide nitride Any nitride insulator may be used.

[0290] Furthermore, transistor 510C shown in Figure 11 is different from transistor 510A shown in Figure 9. The conductor 505 may be provided in a single-layer structure. In this case, the patterned conductor 505 An insulating film that will become an insulator 516 is formed on top of the insulating film, and the upper part of the insulating film is the upper surface of the conductor 505 The material can be removed using methods such as CMP until it is exposed. Here, the upper surface of the conductor 505 is flat. It is preferable to improve the properties. For example, the average surface roughness (Ra) of the upper surface of the conductor 505 should be 1n It should be less than m, preferably less than 0.5 nm, and more preferably less than 0.3 nm. This improves the flatness of the insulating layer formed on the conductive material 505, and the oxide 530b This can improve the crystallinity of oxide 530c.

[0291] <Example of transistor structure 4> An example of the structure of transistor 510D is illustrated using Figures 12A, 12B, and 12C. Figure 12A is a top view of transistor 510D. Figure 12B is the same as Figure 12A but with a dashed line L1 -This is a cross-sectional view of the area indicated by L2. Figure 12C shows the area indicated by the dashed line W1-W2 in Figure 12A. This is a cross-sectional view of the position. Note that in the top view of Figure 12A, some elements have been omitted for clarity. This is illustrated in the diagram.

[0292] Transistor 510D is a modified version of the above transistor. Therefore, to avoid repetition of the explanation... Therefore, I will mainly explain the differences from the transistors mentioned above.

[0293] In Figures 12A to 12C, the conductor 503 is omitted, and it functions as a second gate. The conductive material 505 also functions as wiring. In addition, an insulator 550 is placed on the oxide 530c. It has a metal oxide 552 on the insulator 550. Furthermore, it has a conductive material on the metal oxide 552. It has a body 560, and an insulator 570 on the conductor 560. Furthermore, an insulating material is placed on the insulator 570. It has a body 571.

[0294] The metal oxide 552 preferably has the function of suppressing oxygen diffusion. By providing a metal oxide 552 between the conductive material 560 and the conductive material, which suppresses the diffusion of oxygen, The diffusion of oxygen to body 560 is suppressed. In other words, the amount of oxygen supplied to oxide 530 is reduced. It can be suppressed. Furthermore, it can suppress the oxidation of the conductor 560 by oxygen.

[0295] Furthermore, the metal oxide 552 may function as part of the first gate. For example, An oxide semiconductor that can be used as oxide 530 is used as metal oxide 552. This is possible. In that case, by depositing the conductive material 560 using the sputtering method, metal oxidation can be achieved. The electrical resistance of material 552 can be reduced to form a conductive layer (the aforementioned OC electrode).

[0296] Furthermore, metal oxide 552 may function as part of the gate insulating film. Therefore, when silicon oxide or silicon oxide nitride is used for the insulator 550, metal oxide For 552, it is preferable to use a metal oxide, which is a high-k material with a high dielectric constant. By adopting this laminated structure, it is possible to create a laminated structure that is stable against heat and has a high dielectric constant. Yes, it is possible. Therefore, while maintaining the physical film thickness, the gate voltage applied during transistor operation can be controlled. This allows for a reduction in the position. In addition, the equivalent oxide film thickness (E) of the insulating layer that functions as a gate insulating film is also reduced. This makes it possible to thin the OT (Optical Technology) film.

[0297] In transistor 510D, the metal oxide 552 is shown as a single layer, but a stacked structure of two or more layers is also shown. It may also be constructed as follows: for example, a metal oxide that functions as part of the gate electrode and a gate insulating film. A metal oxide that functions as part of the structure may be layered and provided.

[0298] When the metal oxide 552 functions as a gate electrode, the influence of the electric field from the conductor 560 is... This allows for an improvement in the on-current of transistor 510D without attenuating its performance. Alternatively, When functioning as a gate insulating film, the physical thickness between the insulator 550 and the metal oxide 552 By doing so, the distance between the conductor 560 and the oxide 530 is maintained, allowing the conductor 560 and the acid to move. The leakage current between the material 530 and the insulator 550 can be suppressed. By providing a laminated structure with metal oxide 552, the material between the conductor 560 and the oxide 530 is The rational distance and the electric field strength applied from the conductor 560 to the oxide 530 can be easily and appropriately adjusted. It is possible.

[0299] Specifically, by making the oxide semiconductor that can be used in oxide 530 less resistive, gold It can be used as a group oxide 552. Alternatively, hafnium, aluminum, galvanic M, yttrium, zirconium, tungsten, titanium, tantalum, nickel, germanium A metallic acid containing one or more elements selected from nium, magnesium, etc. Monsters can be used.

[0300] In particular, an insulator containing an oxide of either aluminum or hafnium, or both. Aluminum oxide, hafnium oxide, aluminum and hafnium oxide (Haf It is preferable to use materials such as hafnium aluminate. In particular, hafnium aluminate is It has higher heat resistance than hafnium oxide film. Therefore, in subsequent heat treatment processes, crystals It is preferable because it is less prone to oxidation. Note that metal oxide 552 is not an essential component. The design should be adjusted according to the characteristics of the transistor.

[0301] The insulator 570 has the function of suppressing the permeation of impurities such as water or hydrogen, and oxygen. It is preferable to use insulating materials. For example, aluminum oxide or hafnium oxide can be used. It is preferable that the conductor 560 is acidified by oxygen from above the insulator 570. It can suppress the transformation. Also, water or hydrogen from above the insulator 570 Which impurities are mixed into the oxide 530 via the conductor 560 and the insulator 550? It can be suppressed.

[0302] The insulator 571 functions as a hard mask. By providing the insulator 571, the conductor 56 During the processing of 0, the side surface of the conductor 560 is approximately perpendicular, specifically, the side surface of the conductor 560 and the substrate. The angle formed by the surfaces shall be between 75 degrees and 100 degrees, preferably between 80 degrees and 95 degrees. It is possible.

[0303] Furthermore, the insulator 571 has a function to suppress the permeation of impurities such as water or hydrogen, and oxygen. By using an insulating material, it may also function as a barrier layer. The insulator 570 does not need to be provided.

[0304] Using insulator 571 as a hard mask, insulator 570, conductor 560, metal oxide 5 By selectively removing a portion of 52, the insulator 550, and the oxide 530c, these The sides can be made to roughly coincide, and a portion of the oxide 530b surface can be exposed.

[0305] Furthermore, transistor 510D has a region 531a on a part of the exposed oxide 530b surface. It has region 531a and region 531b. Either region 531a or region 531b is used as the source region. The other side functions as a drain area.

[0306] The formation of regions 531a and 531b can be achieved, for example, by ion implantation or ion doping. Using plasma immersion ion implantation or plasma treatment, exposed oxidative This can be achieved by introducing impurity elements such as phosphorus or boron to the surface of material 530b. In this embodiment and others, "impurity element" refers to an element other than the main component element.

[0307] Furthermore, a metal film is deposited after a portion of the oxide 530b surface is exposed, and then heat treatment is performed. By doing so, the elements contained in the metal film are diffused into the oxide 530b, and region 531a and It is also possible to form region 531b.

[0308] In the region where the impurity element oxide 530b is introduced, the electrical resistivity decreases. Therefore, Regions 531a and 531b are sometimes referred to as the "impurity region" or "low resistance region." .

[0309] By using the insulator 571 and / or the conductor 560 as a mask, region 531a The region 531b can be formed in a self-aligned manner. Regions 531a and / or 531b do not overlap with the conductor 560, thus reducing parasitic capacitance. It can be reduced. Also, the channel formation region and the source drain region (region 531a or No offset region is formed between region 531b). Region 531a and region 531 By forming b in a self-aligned manner, the on-current increases, the threshold This enables features such as reduced voltage and improved operating frequency.

[0310] Furthermore, in order to further reduce the off-current, off-current is controlled between the channel formation region and the source-drain region. A set region may be provided. The offset region is a region with high electrical resistivity, as mentioned above. This is a region where no impurity elements are introduced. The formation of the offset region occurs in insulator 575 This can be achieved by introducing the aforementioned impurity elements after the formation of the insulator 57 5 also functions as a mask, similar to insulator 571. Therefore, oxide 530b is an insulator. By not introducing impurity elements into the region overlapping with 575, the electrical resistivity of that region remains high. It is possible.

[0311] Furthermore, transistor 510D consists of insulator 570, conductor 560, metal oxide 552, and insulation. The body 550 and the oxide 530c have an insulator 575 on their sides. The insulator 575 is 100% induced It is preferable to use an insulator with a low electrical charge. For example, silicon oxide, silicon oxide nitride, and nitrile Silicon oxide, silicon nitride, silicon oxide with added fluorine, silicon oxide with added carbon Silicon oxide with added carbon and nitrogen, porous silicon oxide, or resin It is preferable that it be a fat or similar substance. In particular, silicon oxide, silicon oxide nitride, silicon nitride If silicon oxide having voids is used as the insulator 575, in a later process, It is preferable because it allows for the easy formation of an excess oxygen region. Also, silicon oxide and silicon oxidnitride Con is preferable because it is thermally stable. In addition, the insulator 575 has the function of diffusing oxygen. It is preferable to have it.

[0312] Furthermore, transistor 510D has an insulator 575 and an insulator 574 on an oxide 530. The insulator 574 is preferably deposited using the sputtering method. By using this method, it is possible to form an insulating film with few impurities such as water or hydrogen. For example, aluminum oxide can be used as the insulator 574.

[0313] Note that oxide films produced by sputtering may extract hydrogen from the structure to which the film is deposited. Therefore, insulator 574 absorbs hydrogen and water from oxide 530 and insulator 575. This makes it possible to reduce the hydrogen concentration of oxide 530 and insulator 575.

[0314] <Example of transistor structure 5> Figures 13A to 13C illustrate an example of the structure of transistor 510E. Figure 13A shows This is a top view of the Rangista 510E. Figure 13B is shown in Figure 13A by the dashed line L1-L2. This is a cross-sectional view of the area. Figure 13C is a cross-sectional view of the area shown by the dashed line W1-W2 in Figure 13A. Yes. Note that in the top view of Figure 13A, some elements have been omitted for clarity. ru.

[0315] Transistor 510E is a modified version of the above transistor. Therefore, to avoid repetition of the explanation... Therefore, I will mainly explain the differences from the transistors mentioned above.

[0316] In Figures 13A to 13C, without providing the conductor 542, the exposed surface of the oxide 530b is shown. The part has region 531a and region 531b. Either region 531a or region 531b One region functions as the source region, and the other functions as the drain region. Also, oxide 530b And, between the insulator 574, there is an insulator 573.

[0317] As shown in Figure 13, region 531 (regions 531a and 531b) is oxide 530b. The following elements are added to the region. Region 531 can be used, for example, by using a dummy gate. It can be formed with.

[0318] Specifically, a dummy gate is provided on oxide 530b, and the dummy gate is used as a mask. It is preferable to use and add an element that reduces the resistance of the above oxide 530b. In other words, oxide 530 However, when the element is added to a region that does not overlap with the dummy gate, region 531 is formed. The method for adding the element involves mass-separating the ionized raw material gas and then adding it. Ion implantation method, ion doping method in which ionized source gas is added without mass separation. Plasma immersion ion implantation methods can be used.

[0319] In addition, typical elements that reduce the resistance of oxide 530 include boron and phosphorus. It can also be achieved using hydrogen, carbon, nitrogen, fluorine, sulfur, chlorine, titanium, noble gases, etc. Good. Typical examples of noble gases include helium, neon, argon, krypton, and xenon. There are various methods, such as [mention specific methods]. The concentration of the element in question is determined by secondary ion mass spectrometry (SIMS). Measurements can be taken using methods such as Ion Mass Spectrometry.

[0320] In particular, boron and phosphorus are used in the production of amorphous silicon or low-temperature polysilicon. It is preferable because the equipment can be used. Existing equipment can be repurposed, and This can help curb investment in reserves.

[0321] Next, oxide 530b and an insulating film which will become an insulator 573 are placed on the dummy gate, An insulating film that will become an insulator 574 may be formed. An insulating film that will become an insulator 573, and an insulator By stacking insulating films that make up region 574, the region 531, the oxide 530c and the insulating film are formed. A region can be provided where body 550 and the other body overlap.

[0322] Specifically, an insulating film that will become an insulating film 574 is provided on an insulating film that will become an insulating film 580, and then insulation The insulating film, which will be body 580, will be CMP (Chemical Mechanical Pollution). By performing the (hing) process, a portion of the insulating film that becomes the insulator 580 is removed, and a dummy gate is created. This exposes the insulator 573 that is in contact with the dummy gate when removing it. It is also advisable to remove a portion of it. Therefore, on the side of the opening provided in the insulator 580, 574 and the insulator 573 are exposed, and the bottom surface of the opening is provided in oxide 530b A portion of the exposed region 531 is then exposed. Next, an oxide film which will become oxide 530c is applied to the opening, and an insulating film is applied. After sequentially forming an insulating film that will become the edge 550 and a conductive film that will become the conductor 560, the insulator 5 The oxide film becomes oxide 530c and the insulator 550 through CMP treatment, etc., until 80 is exposed. By removing the insulating film and a portion of the conductive film that becomes the conductor 560, as shown in Figure 13, It is possible to form a transistor.

[0323] Note that insulators 573 and 574 are not essential components. The design should be adjusted as needed depending on the specific requirements.

[0324] The transistor shown in Figure 13 can be repurposed from existing equipment, and furthermore, the conductor 542 By eliminating the need for it, costs can be reduced.

[0325] <Example of transistor structure 6> Figures 14A to 14C illustrate an example of the structure of transistor 510F. Figure 14A shows This is a top view of the Rangista 510F. Figure 14B is shown in Figure 14A by the dashed line L1-L2. This is a cross-sectional view of the area. Figure 14C is a cross-sectional view of the area shown by the dashed line W1-W2 in Figure 14A. Yes. Note that in the top view of Figure 14A, some elements have been omitted for clarity. ru.

[0326] Transistor 510F is a modified version of transistor 510A. Therefore, the explanation is repeated. To prevent this, we will mainly explain the differences from the transistors mentioned above.

[0327] In transistor 510A, a portion of the insulator 574 is located within an opening provided in the insulator 580. It is provided and is provided so as to cover the side surface of the conductor 560. On the other hand, transistor 51 At 0F, an opening is formed by removing parts of the insulators 580 and 574.

[0328] Furthermore, between the conductor 546 and the insulator 580, there is an insulator 576 (insulator) that has barrier properties. 576a and insulator 576b) may be provided. By providing insulator 576, To suppress the reaction of oxygen in the edge material 580 with the conductor 546, thereby preventing oxidation of the conductor 546. It is possible.

[0329] Note that when using an oxide semiconductor as oxide 530, the atomic ratio of each metal atom will differ. It is preferable to have a laminated structure of multiple oxide layers. Specifically, the oxide 530a used In a metal oxide, the atomic ratio of element M in the constituent elements is the metal used in oxide 530b. In oxides, it is preferable that the atomic ratio of element M in the constituent elements is greater than that of the oxide. In the metal oxide used in material 530a, the atomic ratio of element M to In is such that It is preferable that the atomic ratio of element M to In in the metal oxide used for 0b is greater than that of In. Furthermore, in the metal oxide used in oxide 530b, the number of In atoms relative to element M The ratio is greater than the atomic ratio of In to element M in the metal oxide used in oxide 530a. Larger is preferable. Also, oxide 530c is oxide 530a or oxide 530b Metal oxides that can be used for this purpose can be used.

[0330] Oxides 530a, 530b, and 530c are preferably crystalline. In particular, it is preferable to use CAAC-OS. These oxides have few impurities or defects (such as oxygen deficiencies), are highly crystalline, and have a dense structure. Therefore, the oxygen is drawn from oxide 530b by the source electrode or drain electrode. This suppresses the removal of oxygen from oxide 530b. As a result, even after heat treatment, oxygen can be removed from oxide 530b. Because the pull-out of the transistor can be reduced, the 510F transistor has a high manufacturing process. It is stable with respect to temperature (the so-called thermal budget).

[0331] Note that either or both of oxides 530a and 530c may be omitted. 530 may be a single layer of oxide 530b. Oxide 530 may be oxide 530a, oxide When laminating 530b and oxide 530c, oxide 530a and oxide 53 The energy at the lower end of the conduction band for 0c is higher than the energy at the lower end of the conduction band for oxide 530b. It is preferable that the electron parent of oxide 530a and oxide 530c It is preferable that the summing force is smaller than the electron affinity of oxide 530b. In this case, oxide 53 For 0c, it is preferable to use a metal oxide that can be used in oxide 530a. Specifically Specifically, in metal oxides used in oxide 530c, the atomic ratio of element M in the constituent elements is , greater than the atomic ratio of element M in the constituent elements of the metal oxide used in oxide 530b It is preferable that the metal oxide used in oxide 530c contains the element for In. The atomic ratio of element M is the ratio of element M to In in the metal oxide used in oxide 530b. It is preferable that it is greater than the atomic ratio. Also, in the metal oxide used in oxide 530b The atomic ratio of In to element M is the element in the metal oxide used in oxide 530c. It is preferable that the atomic ratio of In to M is greater than that of M.

[0332] Here, at the joint of oxide 530a, oxide 530b, and oxide 530c, The energy levels at the lower end of the guide band change smoothly. In other words, oxide 530a, oxide The energy levels at the lower end of the conduction band at the junction of 530b and oxide 530c are continuous. It can also be said that it undergoes a gradual change or continuous bonding. In order to do this, oxide 5 At the interface between 30a and oxide 530b, and at the interface between oxide 530b and oxide 530c It is desirable to lower the defect level density of the mixed layer that is formed.

[0333] Specifically, oxide 530a and oxide 530b, and oxide 530b and oxide 530c, By having a common element other than the primary element (as the main component), a mixed layer with a low defect level density is formed. It is possible. For example, if oxide 530b is In-Ga-Zn oxide, then oxide 5 As 30a and oxide 530c, In-Ga-Zn oxide, Ga-Zn oxide, oxide Gallium or the like may be used. Alternatively, oxide 530c may be used in a layered structure. For example, I A laminated structure of n-Ga-Zn oxide and Ga-Zn oxide on the In-Ga-Zn oxide. A compound, or an In-Ga-Zn oxide and gallium oxide on the In-Ga-Zn oxide A layered structure can be used. In other words, an In-Ga-Zn oxide and an In-containing A laminated structure with an oxide that does not contain the oxide may be used as oxide 530c.

[0334] Specifically, as oxide 530a, In:Ga:Zn = 1:3:4 [atomic ratio], For this, a metal oxide with an atomic ratio of 1:1:0.5 should be used. Also, as oxide 530b For metals with an atomic ratio of In:Ga:Zn = 4:2:3 or 3:1:2. You can use an oxide. Also, as oxide 530c, In:Ga:Zn=1:3:4[ [Atomic ratio], In:Ga:Zn=4:2:3 [Atomic ratio], Ga:Zn=2:1 [Atomic ratio A metal oxide with a ratio of [ratio] or Ga:Zn=2:5 [atomic ratio] can be used. A specific example of a laminated structure for material 530c is In:Ga:Zn=4:2:3[original Layered structure with atom ratio of [number of atoms] and Ga:Zn=2:1 [number of atoms], In:Ga:Zn=4:2 :3 [atomic ratio] and a layered structure of Ga:Zn=2:5 [atomic ratio], In:Ga:Zn Examples include a 4:2:3 [atomic ratio] and a layered structure with gallium oxide.

[0335] In this case, the main carrier pathway is oxide 530b. Oxide 530a, oxide 53 By configuring 0c as described above, the interface between oxide 530a and oxide 530b, and oxidation The defect level density at the interface between material 530b and oxide 530c can be reduced. Therefore, the influence of interfacial scattering on carrier conduction is reduced, and the transistor 510F is high This allows for obtaining ion current and high frequency characteristics. Furthermore, the oxide 530c is used in the laminated structure. When constructed, the defect level density at the interface between the aforementioned oxide 530b and oxide 530c In addition to the effect of lowering the noise level, the constituent elements of oxide 530c diffuse towards the insulator 550. It is expected that this will be suppressed. More specifically, the oxide 530c is made into a layered structure, and the layered In order to position an In-free oxide above the structure, In can diffuse towards the insulator 550 side. This can be suppressed. The insulator 550 functions as a gate insulator, so In expands. If dispersed, it will result in transistor performance defects. Therefore, oxide 530c is used in a layered structure. This makes it possible to provide a highly reliable display device.

[0336] For oxide 530, it is preferable to use a metal oxide that functions as an oxide semiconductor. For example, For example, the metal oxide that forms the channel-forming region of oxide 530 has a band gap of 2e It is preferable to use a band of V or higher, preferably 2.5 eV or higher. By using metal oxides with a large gap, the off-current of the transistor can be reduced. Yes, it is possible. By using such transistors, low-power semiconductor devices can be provided. .

[0337] <Example of transistor structure 7> Furthermore, in Figures 7 and 8, the conductor 560, which functions as a gate, is connected to the insulator 580. We have described an example of a structure formed inside an opening, but for example, above the conductor, A structure in which such an insulator is provided can also be used. An example of such a transistor structure is shown below. This is shown in Figures 15 and 16.

[0338] Figure 15A is a top view of the transistor, and Figure 15B is a perspective view of the transistor. Figure 16A shows the cross-sectional view of X1-X2 in Figure 15A, and Figure 16 shows the cross-sectional view of Y1-Y2. Shown in B.

[0339] The transistors shown in Figures 15 and 16 have a conductor BGE that functions as a back gate. The insulator BGI, which functions as a gate insulating film, and the oxide semiconductor S, and the gate insulating An insulator TGI that functions as a film, and a conductor T that functions as a front gate. It has GE and a conductor WE that functions as wiring. In addition, the conductor PE is conductive A plug for connecting body WE, oxide S, conductor BGE, or conductor TGE. It has the function of [this]. Here, the oxide semiconductor S is made up of three layers of oxide S1, S2, S3 This shows an example of what is composed of.

[0340] (Embodiment 4) In this embodiment, the gold that can be used in the OS transistor described in the above embodiment is The composition of the group oxides will be explained.

[0341] <Composition of metal oxides> In this specification, CAAC (c-axis aligned crystal), and It may also be written as CAC (Cloud-Aligned Composite). Note that CAAC represents an example of a crystal structure, and CAC represents an example of a function or material composition. .

[0342] CAC-OS or CAC-metal oxide is a material that has conductive properties in some parts. In addition, a portion of the material has insulating properties, while the material as a whole has semiconductor properties. Furthermore, CAC-OS or CAC-metal oxide is used in the transistor channels. When used in a region where a hole is formed, the conductive function is to allow electrons (or holes) that act as carriers to flow. The function of insulation is the function of preventing the flow of electrons, which act as carriers. The function of conductivity is... By having the insulating function and the other function work complementaryly, a switching function is achieved. The function to switch CAC-OS or CAC-metal oxide on / off is added to the CAC-OS or CAC-metal oxide. It is possible. In CAC-OS or CAC-metal oxide, By separating these functions, it is possible to maximize the performance of both.

[0343] Furthermore, CAC-OS or CAC-metal oxide has conductive and insulating properties. It has regions. The conductive region has the conductive function described above, and the insulating region has the insulating function described above. It has the function of [this]. Furthermore, within the material, the conductive region and the insulating region are at the nanoparticle level. In some cases, they are separated by a rib. Also, conductive regions and insulating regions are located within the material. They may be unevenly distributed. Furthermore, the conductive regions appear blurred around the edges and connected in a cloud-like pattern. There are cases where this occurs.

[0344] Furthermore, in CAC-OS or CAC-metal oxide, the conductive region and the insulating region The marginal region is defined as being between 0.5 nm and 10 nm, preferably between 0.5 nm and 3 nm. These particles may be dispersed in the material at the following sizes.

[0345] Furthermore, CAC-OS or CAC-metal oxide has different band gaps. It is composed of the following components. For example, CAC-OS or CAC-metal oxi de consists of a component with a wide gap due to the insulating region and a component with a wide gap due to the conductive region. It consists of a component having a low gap. In this configuration, when the carrier is flowing... In components with a narrow gap, the carrier mainly flows. A component having a wide gap acts complementaryly with a component having a narrow gap. In conjunction with the components, carriers also flow to components with a wide gap. Therefore, the above C AC-OS or CAC-metal oxide is applied to the channel formation region of the transistor. When used, a high current driving force is required in the transistor's ON state, i.e., a large ON current. Furthermore, a high field-effect mobility can be obtained.

[0346] In other words, CAC-OS or CAC-metal oxide is a matrix composite material. (matrix composite), or metal matrix composite (metal It can also be called a matrix composite.

[0347] <Structure of metal oxides> Oxide semiconductors are divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. As a non-single-crystal oxide semiconductor, for example, CAAC-OS (c-axis ali gned crystalline oxide semiconductor), polycrystalline crystalline oxide semiconductor, nc-OS (nanocrystalline oxide semiconductor) conductor), pseudo-amorphous oxide semiconductor (a-like OS: amorphous (us-like oxide semiconductor) and amorphous oxide semiconductor These are some examples.

[0348] For the oxide semiconductor used in transistors, it is preferable to use a highly crystalline thin film. It seems that using this thin film can improve the stability or reliability of transistors. Yes, it is possible. The thin film can be, for example, a thin film of a single-crystal oxide semiconductor or a thin film of a polycrystalline oxide semiconductor. Thin films are an example. However, thin films of single-crystal oxide semiconductors or polycrystalline oxide semiconductors are examples. Forming such a thin film on a substrate requires a high-temperature or laser heating process. This increases manufacturing costs and also reduces throughput.

[0349] In 2009, In-Ga-Zn oxide having a CAAC structure (CAAC-IGZO), The discovery of (called) has been reported in Non-Patent Documents 1 and 2. CAAC-IGZO has c-axis orientation, grain boundaries are not clearly visible, and it is suitable for low temperatures. It has been reported that it can be formed on a substrate using CAAC-IGZO. Transistors have been reported to possess excellent electrical characteristics and reliability.

[0350] Furthermore, in 2013, In-Ga-Zn oxide (nc-IGZO) having an nc structure, (See Non-Patent Document 3) was discovered. Here, nc-IGZO is used in minute regions ( For example, the atomic arrangement has periodicity in the region between 1 nm and 3 nm, and different regions It has been reported that no regularity is observed in the crystal orientation between these crystals.

[0351] Non-patent documents 4 and 5 describe the above CAAC-IGZO, nc-IGZO, and and the average crystal size of each thin film of low-crystallinity IGZO after electron beam irradiation. The following changes are shown. In thin films of IGZO with low crystallinity, before irradiation with an electron beam... Crystalline IGZO with a crystal size of approximately 1 nm has been observed. Therefore, here, In IGZO, a completely amorphous structure (completely amorphous s It has been reported that the presence of a structure could not be confirmed. Furthermore, the crystallinity was low. Compared to IGZO thin films, CAAC-IGZO thin films and nc-IGZO thin films are electrically... It has been shown to have high stability against sub-beam irradiation. Therefore, it is suitable as a semiconductor for transistors. Therefore, it is preferable to use a thin film of CAAC-IGZO or a thin film of nc-IGZO.

[0352] CAAC-OS has c-axis orientation and multiple nanocrystals are linked in the ab-plane direction. Furthermore, it has a distorted crystal structure. Note that distortion refers to the region where multiple nanocrystals are connected. Within the region, between a region with aligned lattice arrangements and another region with aligned lattice arrangements, This refers to the part where the direction has changed.

[0353] Nanocrystals are based on a hexagonal structure, but they are not necessarily regular hexagons; they can also be non-regular hexagonal. Yes, it exists. Furthermore, the distortion may have lattice arrangements such as pentagons and heptagons. Furthermore, in CAAC-OS, even near strain, clear grain boundaries (grain bounds) are present. It is not possible to confirm the dally (also called dally). In other words, due to the distortion of the lattice arrangement, the crystal grain It can be seen that the formation of the boundary is suppressed. This is because CAAC-OS is in the ab-plane direction. The oxygen atoms are not densely arranged, and the substitution of metal elements reduces the bond distance between atoms. This is thought to be because the distortion can be tolerated through changes and other processes.

[0354] Furthermore, CAAC-OS consists of a layer containing indium and oxygen (hereinafter referred to as the In layer), and elements A layered crystalline structure in which layers containing M, zinc, and oxygen (hereinafter referred to as (M,Zn) layers) are stacked. It tends to have a layered structure (also called a structure). Note that indium and element M are relative to each other. It is interchangeable, and if element M in the (M,Zn) layer is replaced with indium, then (In,M,Zn It can also be represented as a layer. Furthermore, if the indium in the In layer is replaced by element M, (In, It can also be represented as layer M.

[0355] CAAC-OS is a highly crystalline oxide semiconductor. On the other hand, CAAC-OS has a clear bond. Since grain boundaries cannot be identified, a decrease in electron mobility caused by grain boundaries does not occur. It can be said that the crystallinity of oxide semiconductors is reduced due to the inclusion of impurities and the formation of defects. Because it may cause problems, CAAC-OS is an oxide with few impurities and defects (such as oxygen deficiencies). It can also be called a semiconductor. Therefore, oxide semiconductors containing CAAC-OS have stable physical properties. Therefore, oxide semiconductors containing CAAC-OS are heat-resistant and highly reliable. CAAC-OS can withstand high temperatures (so-called thermal budget) in the manufacturing process. It is stable. Therefore, when using CAAC-OS in OS transistors, the manufacturing process is stable. This will broaden the scope of possibilities.

[0356] nc-OS is used in minute regions (for example, regions between 1 nm and 10 nm, especially between 1 nm and 3 nm). It has periodicity in the atomic arrangement in the region of less than nm. Furthermore, nc-OS has different nanometers. No regularity in crystal orientation is observed between crystals. Therefore, no orientation is observed throughout the entire film. Therefore, depending on the analysis method, nc-OS can be classified as a-like OS or amorphous oxide semiconductor. It can sometimes be difficult to distinguish between them.

[0357] a-like OS is an oxide semiconductor having a structure between nc-OS and amorphous oxide semiconductors. It is a conductor. a-like OS has porous or low-density regions. That is, a-like OS has lower crystallinity compared to nc-OS and CAAC-OS.

[0358] Oxide semiconductors can take on diverse structures, each possessing different properties. One embodiment of the present invention Oxide semiconductors include amorphous oxide semiconductors, polycrystalline oxide semiconductors, a-like OS, and nc -OS and CAAC-OS may have two or more types.

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

[0360] Furthermore, by using the above oxide semiconductor in transistors, transistors with high field-effect mobility can be produced. It is possible to realize a transistor. Furthermore, it is possible to realize a highly reliable transistor. .

[0361] Furthermore, transistors using the above oxide semiconductor exhibit extremely high leakage current in the non-conductive state. This is small, specifically, the off-current per 1 μm of transistor channel width is yA / μm (10 -24 Non-patent document 6 shows that it is on the order of A / μm. For example, acid Low power consumption by utilizing the characteristic of low leakage current of transistors using synthetic semiconductors. The CPU and other components have been disclosed (see Non-Patent Document 7).

[0362] Furthermore, the characteristic of low leakage current in transistors using oxide semiconductors is utilized. Applications of transistors in display devices have been reported (see Non-Patent Document 8). The displayed image changes dozens of times per second. (Number of image changes per second) This is called the refresh rate. The refresh rate is also sometimes called the drive frequency. It is also said that such high-speed screen switching, which is difficult for the human eye to perceive, is a source of eye strain. This is considered to be the cause. Therefore, by lowering the refresh rate of the display device, the image It has been proposed to reduce the number of rewrites. Also, a drive that lowers the refresh rate has been proposed. This driving method makes it possible to reduce the power consumption of the display device. This is called Idling Stop (IDS) drive.

[0363] Furthermore, it is preferable to use an oxide semiconductor with a low carrier density for the transistor. When lowering the carrier density of an oxide semiconductor film, the impurity concentration in the oxide semiconductor film The defect level density should be reduced by lowering the impurity concentration. In this specification, the impurity concentration is low and the defect level density is low. A low density of pitting is referred to as high-purity genuine or substantially high-purity genuine.

[0364] Furthermore, oxide semiconductor films that are high-purity intrinsic or substantially high-purity intrinsic have a low defect level density. Therefore, the trap level density may also be low.

[0365] Furthermore, the time required for charges trapped in the trap levels of oxide semiconductors to disappear is long. Furthermore, it can behave as if it were a fixed charge. Therefore, it can behave as if it were a fixed charge. Transistors in which a channel formation region is formed in an oxide semiconductor exhibit unstable electrical properties. There are cases where this is the case.

[0366] Therefore, in order to stabilize the electrical characteristics of the transistor, the impurity concentration in the oxide semiconductor must be Reducing it is effective. Also, in order to reduce the impurity concentration in oxide semiconductors, It is also preferable to reduce the concentration of impurities in the contacting film. Examples of impurities include hydrogen, nitrogen, and aluminum. Examples include potash metals, alkaline earth metals, iron, nickel, and silicon.

[0367] <Impurities> Here, we will explain the effects of various impurities in oxide semiconductors.

[0368] In oxide semiconductors, if silicon or carbon, which are among the Group 14 elements, are present, the oxide Defect levels are formed in semiconductors. Therefore, silicon and carbon in oxide semiconductors. The concentration of silicon and carbon near the interface with the oxide semiconductor (by secondary ion mass spectrometry) SIMS (Secondary Ion Mass Spectrometry) The resulting concentration is 2 × 10 18 atoms / cm 3 The following is preferably 2 × 10 17 at oms / cm 3 The following applies:

[0369] Furthermore, if alkali metals or alkaline earth metals are present in the oxide semiconductor, defect levels are formed. This can result in the generation of carriers. Therefore, alkali metals or alkaline earth metals Transistors using oxide semiconductors containing this material tend to exhibit normally-on characteristics. Therefore, reducing the concentration of alkali metals or alkaline earth metals in oxide semiconductors is possible. Preferably. Specifically, alkali metals or a in oxide semiconductor obtained by SIMS The concentration of rutile earth metals is 1 × 10⁻⁶ 18 atoms / cm 3 The following is preferably 2 × 10 1 6 atoms / cm 3 Do the following:

[0370] Furthermore, in oxide semiconductors, when nitrogen is present, electrons, which are carriers, are generated. The density increases, making it easier to convert to n-type. As a result, oxide semiconductors containing nitrogen can be converted into semiconductors. The transistor used tends to exhibit normally-on characteristics. Therefore, in the oxide semiconductor... Therefore, it is preferable that nitrogen is reduced as much as possible. For example, nitrogen concentration in oxide semiconductors In SIMS, the degree is 5 × 10 19 atoms / cm3 Less than 5 × 10 1 8 atoms / cm 3 More preferably 1 × 10 18 atoms / cm 3 The following, Preferably 5 × 10 17 atoms / cm 3 The following applies:

[0371] Furthermore, the hydrogen contained in oxide semiconductors reacts with the oxygen bonded to the metal atoms to form water. This can sometimes form an oxygen vacancy. When hydrogen enters this oxygen vacancy, the electrons, which are carriers, In some cases, this can be generated. Also, some of the hydrogen combines with oxygen that is bonded to a metal atom, resulting in a It can generate electrons, which are rear electrons. Therefore, using an oxide semiconductor containing hydrogen... Transistors tend to exhibit normally-on characteristics. Therefore, hydrogen in oxide semiconductors It is preferable that it be reduced as much as possible. Specifically, in oxide semiconductors, SIM The hydrogen concentration obtained by S is 1 × 10 20 atoms / cm 3 Less than 1 × 1 0 19 atoms / cm 3 Less than 5x10 18 atoms / cm 3 less than, More preferably 1 × 10 18 atoms / cm 3 Less than.

[0372] Using oxide semiconductors with sufficiently reduced impurities in the channel formation region of transistors. This allows for the provision of stable electrical characteristics.

[0373] The discovery of CAAC and nc structures led to the development of oxide semiconductors having CAAC or nc structures. Improvement of the electrical characteristics and reliability of transistors using a body, and reduction of manufacturing costs. It contributes to improved performance and throughput. Furthermore, the transistor has low leakage current. Research is underway to apply this characteristic to display devices and LSIs of the transistor. It is.

[0374] This embodiment may be implemented in appropriate combination with other embodiments described herein. It is possible.

[0375] (Embodiment 5) In the embodiments described above, an example was shown in which a charging control circuit is provided on a flexible substrate, but there are no particular limitations. Alternatively, a protection circuit, a second switch, a secondary coil, a sensor, etc., may be provided on the same circuit board. The charging control circuit is formed on a flexible substrate and can be bent, and the secondary battery It can detect abnormalities such as microshorts. Furthermore, according to one embodiment of the present invention, the charging control cycle The circuit can be installed on the side of the secondary battery, achieving space savings and a reduction in the number of components used. It is possible.

[0376] This embodiment provides an example of an electronic device equipped with a wireless charging control system and a charging control circuit. This will be explained using Figure 17.

[0377] The robot 7100 includes a rechargeable battery, light sensor, microphone, camera, speaker, and Spray, various sensors (infrared sensor, ultrasonic sensor, accelerometer, piezoelectric sensor, light) It is equipped with sensors (such as gyro sensors) and a movement mechanism. Secondary of the robot 7100 By applying a wireless charging control system and charging control circuit according to one aspect of the present invention to a battery, secondary It can detect abnormalities such as battery overcharging and micro-short circuits.

[0378] The microphone has the function of detecting acoustic signals such as the user's voice and ambient sounds. Furthermore, the speaker has the function of emitting audio signals such as voice and warning sounds. The 7100 analyzes the audio signal input via the microphone and performs the necessary actions. Audio signals can be emitted from the speaker. The robot 7100 has a microphone. It is also possible to communicate with the user using a speaker.

[0379] The camera has the function of imaging the area around the robot 7100. Also, the robot 7100 It has the function of moving using a moving mechanism. Robot 7100 uses a camera to observe its surroundings. By capturing images and analyzing them, it's possible to detect obstacles and other issues while moving.

[0380] Aircraft 7120 is an autonomous aircraft equipped with propellers, cameras, and a secondary battery. To have the ability.

[0381] Furthermore, the secondary battery of the aircraft 7120 is equipped with a wireless charging control system and charging control system according to one aspect of the present invention. By applying an electrical control circuit, in addition to weight reduction, it also prevents overcharging of secondary batteries and micro-short circuits. It can detect anomalies.

[0382] The 7140 cleaning robot has a rechargeable battery, a display located on the top, and a side panel. It has multiple cameras, brushes, control buttons, various sensors, etc. Although not shown in the illustration, sweeping The cleaning robot 7140 is equipped with wheels, a suction nozzle, etc. The 40 is self-propelled, can detect dust, and can suck up the dust from a suction port located on its underside. This allows for the wireless connection of the secondary battery of the cleaning robot 7140 to one aspect of the present invention. By applying a charging control system and a charging control circuit, the number of components used is reduced, and the secondary battery It can detect abnormalities such as overcharging and micro-short circuits.

[0383] As an example of a mobile device, we show the electric vehicle 7160. The electric vehicle 7160 uses a secondary battery, Thai It has a steering system, brakes, and a camera. It connects to the secondary battery of the electric vehicle 7160. By applying a wireless charging control system and charging control circuit according to one aspect of the present invention, the components used The number of devices can be reduced, and abnormalities such as overcharging of secondary batteries and micro-short circuits can be detected. can.

[0384] In the above, an electric vehicle was described as an example of a mobile vehicle, but mobile vehicles are electric This is not limited to automobiles. For example, other modes of transport include trains, monorails, ships, and aircraft (helicopters). Other examples include helicopters, unmanned aerial vehicles (drones), airplanes, and rockets. A wireless charging control system according to one aspect of the present invention that electrically connects to the secondary battery of a mobile device. Furthermore, by applying a charging control circuit, the number of components used is reduced, and overcharging of the secondary battery and microphone are prevented. It can detect abnormalities such as short circuits.

[0385] A cylindrical secondary battery equipped with a charging control circuit 700 and / or a charging control circuit 730. The battery pack is for the Smartphone 7210, PC 7220 (Personal Computer), and G It can be incorporated into the 7240 radio unit, the 7260 game unit, etc. Note that the charging control circuit 70 A cylindrical secondary battery equipped with 0 corresponds to the charging control circuit 10 shown in Embodiment 1. The battery pack equipped with the charging control circuit 730 is the same as the charging control circuit 914 shown in Embodiment 2. It is equivalent to the following. It is equipped with charging control circuits 700 and 730 that safely control the operation of the small battery pack. While incorporating these features, the design also achieves a configuration that can accommodate the space-saving requirements resulting from the miniaturization of smartphone casings. It is also possible to do so.

[0386] The Smartphone 7210 is an example of a mobile information terminal. It has an microphone, camera, speaker, various sensors, and display unit. Wireless charging. These peripheral devices are controlled by the control system and charging control circuit 730. A wireless charging control system according to one aspect of the present invention that electrically connects to the secondary battery of the 7210 By applying a m and charging control circuit, the number of components used is reduced, and overcharging of the secondary battery and mining are prevented. It can detect abnormalities such as cross-shorts, thereby enhancing safety.

[0387] The PC7220 is an example of a notebook PC. The rechargeable battery of the notebook PC is electrically connected. By applying the wireless charging control system and charging control circuit according to one aspect of the present invention, By reducing the number of components and detecting abnormalities such as overcharging of the secondary battery and micro-short circuits... This allows for increased safety.

[0388] Game console 7240 is an example of a portable game console. Game console 7260 is a home console. This is an example of a game console. The game console 7260 has a controller 7262 that can be connected wirelessly or wired. It is connected. The battery pack, equipped with a charging control circuit 730, is connected to the controller 7262. By incorporating a cylindrical rechargeable battery equipped with a charging control circuit, the number of components used can be reduced. Furthermore, it can detect abnormalities such as overcharging of the secondary battery and micro-short circuits.

[0389] Furthermore, the charging control circuit 700 or charging control circuit 730 is not limited to secondary batteries, but can also be used with primary batteries. By incorporating this feature, power consumption can be reduced, thereby suppressing battery leakage and extending the battery's lifespan. It is achievable. Furthermore, it is possible to realize a configuration that can accommodate space savings due to the miniaturization of the enclosure. It is possible.

[0390] Figure 18A shows an example of a wearable device. A wearable device has a power source and A primary or secondary battery is used. Also, the user is using it for daily life or outdoors. To enhance water resistance, only wired charging is available, where the connector part is exposed. What is desired is a wearable device that can also be charged wirelessly.

[0391] For example, it can be mounted on a spectacle-type device 400 as shown in Figure 18A. The vise 400 has a frame 400a and a display unit 400b. The frame has a curved shape. By incorporating a primary or secondary battery in the temple of the 400a, the weight balance is improved. This allows for the creation of glasses-type devices 400 with extended continuous use time. A charging control circuit is located on the side of the battery. It may also be equipped with a circuit to safely control the operation of the primary battery, and in conjunction with the miniaturization of the housing... This allows for a configuration that can accommodate space-saving requirements.

[0392] It can also be mounted on a headset-type device 401. 401 comprises at least a microphone unit 401a, a flexible pipe 401b, and an earphone. It has a section 401c. Primary power is supplied inside the flexible pipe 401b and the earphone section 401c. A battery or secondary battery can be provided. A charging control circuit may be provided on the side of the battery, and a primary battery may be provided. It incorporates a circuit to safely control battery operation while also accommodating space savings due to the miniaturization of the casing. It is possible to realize the desired configuration.

[0393] Furthermore, it can be mounted on a device 402 that can be directly attached to the body. A primary battery or a secondary battery 402b can be installed inside the thin housing 402a of 2. The battery may be equipped with a charging control circuit on its side, and a circuit for safely controlling the operation of the primary battery may be incorporated. At the same time, it is possible to realize a configuration that can accommodate space savings due to the miniaturization of the enclosure.

[0394] Furthermore, it can be mounted on a device 403 that can be attached to clothing. A primary battery or a secondary battery 403b can be installed inside the thin housing 403a. A charging control circuit may be provided on the side of the battery, and a circuit for safely controlling the operation of the primary battery may be installed. Furthermore, it is possible to realize a configuration that can accommodate space savings due to the miniaturization of the enclosure.

[0395] Furthermore, it can be installed in a wristwatch-type device 405. The wristwatch-type device 405 displays It has a section 405a and a belt section 405b, and the display section 405a or the belt section 405b, A primary or secondary battery may be provided. A charging control circuit may also be provided on the side of the battery. It incorporates a circuit to safely control the operation of the primary battery, while also saving space due to the miniaturization of the casing. This allows for the creation of a configuration that can accommodate these requirements.

[0396] The display unit 405a can display not only the time, but also various other information such as incoming emails and phone calls. It is possible.

[0397] Furthermore, the wristwatch-type device 405 is a wearable device that is worn directly on the wrist. Therefore, it may be equipped with sensors to measure the user's pulse, blood pressure, etc. Furthermore, it is possible to accumulate data related to health and use it to help maintain health.

[0398] Furthermore, it can be mounted on a belt-type device 406. The belt-type device 406 is a belt It has a belt section 406a and a wireless power supply and receiving section 406b, and inside the belt section 406a It can be equipped with a primary or secondary battery. Often, a circuit is incorporated to safely control the operation of the primary battery, while also saving space by miniaturizing the casing. This allows for a configuration that can accommodate the transition to a more robust system.

[0399] Furthermore, by using the charging control system according to one aspect of the present invention as an energy storage device for daily electronic products... We can provide lightweight and long-lasting products. For example, as everyday electronic products, electric toothbrushes, electric Examples include shavers and electric beauty devices, and the power storage devices for these products are those used by the user. A stick-shaped design is desired for ease of handling, and a small, lightweight, and high-capacity battery is preferred. The battery may also be equipped with a charging control circuit on its side to safely power the secondary or primary battery. It incorporates a control circuit while achieving a configuration that can accommodate space savings due to the miniaturization of the enclosure. It is possible.

[0400] Figure 18B shows a detector using a primary battery with a charging control circuit on its side, such as a fire alarm. Here is an example.

[0401] In Figure 18B, the alarm device 8100 is a residential fire alarm, and consists of a detection unit and a speaker. It has a unit, a microcomputer, and a battery 8101. If an abnormality is detected, an alarm sounds. The speaker section of the device 8100 can output sound. It may be equipped with an electrical control circuit, and may include a circuit to safely control the operation of a secondary or primary battery. Furthermore, because power consumption can be reduced, battery leakage can be suppressed, resulting in longer battery life. This allows for a configuration that can accommodate space savings resulting from the miniaturization of the enclosure.

[0402] In this specification, the term "fire alarm" refers to any device that promptly reports the occurrence of a fire. For example, residential fire alarms, automatic fire alarm systems, and the use of such automatic fire alarm systems. Fire detectors and other similar devices are also included in the definition of fire alarms.

[0403] This embodiment can be implemented in appropriate combination with the configurations described in other embodiments. It is possible. [Explanation of symbols]

[0404] 10: Charging control circuit, 11: Flexible substrate, 12: First terminal, 13: Second terminal, 14: Third terminal, 15: secondary battery, 16: charging circuit, 17: electronic device, 18: electrode, 19: electric Pole, 20: First switch, 22: Power receiving circuit, 23: Processor, 24: Power supply circuit, 30 : Antenna, 31: Primary coil, 100: Memory cell, 101: Secondary battery, 102: Comparison Circuit, 103: Memory, 104: Memory, 105: Disconnection switch, 106: Control circuit, 201: Positive electrode cap, 202: Battery can, 203: Positive electrode terminal, 204: Positive electrode, 205: Se Parator, 206: Negative electrode, 207: Negative electrode terminal, 208: Insulating plate, 209: Insulating plate, 211 :PTC element, 212: safety valve mechanism, 300: transistor, 311: circuit board, 313: semiconductor Conductor region, 314a: Low resistance region, 314b: Low resistance region, 315: Insulator, 316: Conductor Electrical body, 320: insulator, 322: insulator, 324: insulator, 326: insulator, 328: conductor Electrical body, 330: Conductor, 350: Insulator, 352: Insulator, 354: Insulator, 356: Conductor Electrical body, 360: insulator, 362: insulator, 364: insulator, 366: conductor, 370: insulator Edge material, 372: insulator, 374: insulator, 376: conductor, 380: insulator, 382: insulator Edge body, 384: insulator, 386: conductor, 400: spectacle-type device, 400a: frame ,400b: Display unit, 401: Headset-type device, 401a: Microphone unit, 401b : Flexible pipe, 401c: Earphone section, 402: Device, 402a: Housing, 402b: secondary battery, 403: device, 403a: housing, 403b: secondary battery, 405 : Wristwatch-type device, 405a: Display unit, 405b: Strap unit, 406: Strap-type device S, 406a: Belt section, 406b: Wireless power supply and receiving section, 500: Transistor, 5 03: Conductive, 503a: Conductive, 503b: Conductive, 505: Conductive, 505a: Conductive Body, 505b: Conductor, 510: Insulator, 510A: Transistor, 510B: Transistor 510C: Transistor, 510D: Transistor, 510E: Transistor, 5 10F: Transistor, 511: Insulator, 512: Insulator, 514: Insulator, 516: Insulator Edge material, 518: Conductor, 520: Insulator, 521: Insulator, 522: Insulator, 524: Insulator Related material, 530: oxide, 530a: oxide, 530b: oxide, 530c: oxide, 53 1: Area, 531a: Area, 531b: Area, 540a: Conductor, 540b: Conductor, 5 42: conductor, 542a: conductor, 542b: conductor, 543: region, 543a: region, 543b: region, 544: insulator, 545: insulator, 546: conductor, 546a: conductor , 546b: Conductor, 547: Conductor, 547a: Conductor, 547b: Conductor, 548: Conductor, 550: Insulator, 552: Metal oxide, 560: Conductor, 560a: Conductor, 5 60b: Conductor, 570: Insulator, 571: Insulator, 573: Insulator, 574: Insulator 575: Insulator, 576: Insulator, 576a: Insulator, 576b: Insulator, 580: Insulator Body, 581: Insulator, 582: Insulator, 584: Insulator, 586: Insulator, 600: Capacitance Element, 610: Conductor, 612: Conductor, 620: Conductor, 630: Insulator, 650: Insulator Edge body, 700: charging control circuit, 730: charging control circuit, 910: flexible substrate, 911: contact 913: Secondary battery, 914: Charging control circuit, 916: Insulating sheet layer, 930: Housing Body, 931: Negative electrode, 932: Positive electrode, 933: Separator, 950: Winding body, 951: Terminal 952: Terminal, 1400: Battery, 1402: Positive electrode, 1404: Negative electrode, 7100: Robot 7120: Flying object, 7140: Cleaning robot, 7160: Electric vehicle, 7210: Smartphone, 7220: PC, 7240: Game console, 7260: Game console, 7262 : Controller, 8100: Alarm device, 8101: Battery

Claims

1. A rechargeable battery that can be charged wirelessly, A charging control circuit is electrically connected to the aforementioned secondary battery, A charging circuit electrically connected to the aforementioned charging control circuit, The secondary battery and the charging circuit are electrically connected, and the circuit includes a cutoff switch. The charging control circuit has a memory that holds the data of the cutoff switch, The charging control circuit has a flexible substrate, The flexible substrate is a battery pack arranged along the side surface of the secondary battery, The battery pack has a charging control circuit that, when it detects overcharging of the secondary battery, simultaneously turns off the cutoff switch and the output transistor of the charging circuit.

2. A rechargeable battery that can be charged wirelessly, A charging control circuit is electrically connected to the aforementioned secondary battery, A charging circuit electrically connected to the aforementioned charging control circuit, The secondary battery and the charging circuit are electrically connected, and the circuit includes a cutoff switch. The aforementioned secondary battery has a cylindrical shape, The charging control circuit has a memory that holds the data of the cutoff switch, The charging control circuit has a flexible substrate, The flexible substrate is arranged along the side surface of the secondary battery and is part of a battery pack having a curved region, The battery pack has a charging control circuit that, when it detects overcharging of the secondary battery, simultaneously turns off the cutoff switch and the output transistor of the charging circuit.

3. In claim 1 or claim 2, The charging control circuit has the function of controlling the charging voltage of the secondary battery and the function of controlling the charging current of the battery pack.

4. In any one of claims 1 to 3, The charging control circuit has a function to control the amount of charging current according to the degree of degradation of the secondary battery, in a battery pack.

5. In any one of claims 1 to 4, The charging control circuit is a battery pack having a function to detect a micro-short circuit in the secondary battery.

6. In any one of claims 1 to 5, The charging control circuit is a battery pack having a function to detect the terminal voltage of the secondary battery.

7. In any one of claims 1 to 6, The aforementioned cutoff switch has a transistor, The channel formation region of the transistor is an oxide semiconductor, and the battery pack is provided.

8. In any one of claims 1 to 7, The aforementioned cutoff switch has a transistor, The channel formation region of the transistor is a battery pack containing indium and oxygen.

9. In any one of claims 1 to 8, The aforementioned cutoff switch has a transistor, The channel formation region of the transistor is a battery pack having In-Ga-Zn oxide.

10. In any one of claims 1 to 9, The channel formation region of the output transistor of the charging circuit is an oxide semiconductor, in the battery pack.

11. In any one of claims 1 to 10, The channel formation region of the output transistor of the charging circuit is a battery pack having indium and oxygen.

12. In any one of claims 1 to 11, The channel formation region of the output transistor of the charging circuit is a battery pack having In-Ga-Zn oxide.

13. An electronic device having a battery pack according to any one of claims 1 to 12.

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