Display device

Abstract

To provide a display device with which it is possible to perform external correction in parallel with display operation.SOLUTION: A display device has pixels provided in a matrix form and a readout circuit provided external to the pixels, the pixels having a light-emitting element and a transistor for supplying electric current to the light-emitting element. In the display device, when all of a plurality of specific pixels are black display, unevenness in a current characteristic of a drive transistor is corrected in an address period by reading out current characteristic information of a drive transistor that a prescribed pixel among the plurality of pixels has.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] One embodiment of the present invention is a semiconductor device, a display device, an electronic device, or a driving method thereof. The present invention relates to a manufacturing method thereof.

[0002] Note that one embodiment of the present invention is not limited to the above technical fields. The technical field relates to an article, a method, or a manufacturing method. , process, machine, manufacture, or composition of matter Therefore, one embodiment of the present invention disclosed in this specification more specifically relates to The technical fields include light-emitting devices, power storage devices, imaging devices, storage devices, and driving methods thereof. or the manufacturing method thereof can be mentioned as an example. [Background technology]

[0003] In recent years, various devices such as television receivers, personal computers, and smartphones have become Display devices are used in a variety of electronic devices, and display devices are becoming increasingly high-definition and low-power. Efforts are being made to improve performance in various areas, including power generation.

[0004] These display devices are made up of a plurality of pixels arranged in a matrix, each of which has a transistor. Active matrix display devices that use transistors to control each pixel are often used. In an active matrix display device, each pixel is controlled by a transistor. Variation in transistor characteristics between pixels or deterioration of transistor characteristics can affect the display quality of each pixel. This can cause unevenness in the display and burn-in. This sometimes happens.

[0005] In an active matrix display device that uses light-emitting elements as display elements, A driving transistor is provided to control the current supplied to the light emitting element. The threshold voltage, mobility, channel length, or channel width of the transistor to be used If one of these varies from pixel to pixel, the brightness of the light-emitting element in each pixel will vary. .

[0006] As a method for preventing such variations in the brightness of light-emitting elements, a driving transistor is provided inside the pixel. A method for correcting the variation in threshold voltage (hereinafter referred to as internal correction) has been proposed. (Patent Document 1).

[0007] In addition, the threshold voltage of the driving transistor is read out to the outside of the pixel, and the threshold voltage is A method of inputting a signal that has been corrected for fluctuations (hereinafter referred to as external correction) has been proposed (Patent Permitted document 2). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-233933 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-195813 Summary of the Invention [Problem to be solved by the invention]

[0009] When external correction is performed, the current flowing through the transistor may be output to the outside of the pixel. Alternatively, the potential of a terminal of a transistor may be output to the outside of the pixel. If external correction is performed during display operation, the current supplied to the light-emitting element will change. Therefore, if external correction is performed while the display is in operation, the display may change. As such, it may be difficult to perform external correction in parallel with the display operation of the display device. Alternatively, when external correction is performed during a period when the display device is not performing a display operation, Since correction operations must be performed on a large number of pixels, the correction period is long. There was a problem with that.

[0010] One embodiment of the present invention is a novel semiconductor device, a novel display device, a method for driving the novel semiconductor device, Another object is to provide a novel method for driving a display device.

[0011] Another embodiment of the present invention is a display device that can perform external correction in parallel with a display operation. Another object of one embodiment of the present invention is to provide an external compensation device in parallel with a display operation. Another object of the present invention is to provide a method for driving a display device capable of performing correction. One aspect of the present invention aims to provide a display device with little display unevenness and a driving method thereof. Another embodiment of the present invention is a display device capable of displaying a high-definition image. Another object of one embodiment of the present invention is to provide a transistor. Semiconductor device capable of reducing the influence of variations in transistor characteristics, and driving method thereof Another object of the present invention is to provide a method for reducing the threshold voltage of a transistor. A semiconductor device capable of reducing the influence of variations in value voltage and a driving method thereof are provided. Another object of one embodiment of the present invention is to provide a semiconductor device that can reduce variations in mobility of transistors. To provide a semiconductor device capable of reducing the influence of adhesion and a method for driving the same. This is one of the challenges.

[0012] Note that the problems of one embodiment of the present invention are not limited to the above-listed problems. This does not preclude the existence of other issues. Other issues may be discussed in the following sections. Problems not mentioned in this section are problems that a person skilled in the art would be able to understand by reading the specification or This can be derived from descriptions in drawings, etc., and can be extracted appropriately from these descriptions. One aspect of the present invention is to achieve at least one of the above-listed and / or other objects. It solves three problems. [Means for solving the problem]

[0013] One embodiment of the present invention includes a first pixel and a second pixel, and the first pixel includes a first transistor. and a first light-emitting element, and the second pixel has a second transistor and a second light-emitting element. The first light emitting element is electrically connected to the first transistor, and the second light emitting element is electrically connected to the second transistor. The first pixel is electrically connected to the first transistor, and the first pixel reads information about the current characteristics of the first transistor. a function of performing a first operation of inputting a signal for reading out the current characteristics of the first transistor; A second operation is performed to read out information and input a data signal (video signal) to a second pixel. The semiconductor device has the following functions.

[0014] Alternatively, one embodiment of the present invention includes a first pixel, a second pixel, and a third pixel, and the first pixel The first pixel has a first transistor and a first light-emitting element, and the second pixel has a second transistor and a a third pixel having a third transistor and a third light-emitting element; The first light-emitting element is electrically connected to the first transistor, and the second light-emitting element is electrically connected to the second transistor. the third light-emitting element is electrically connected to the third transistor; The first pixel and the third pixel are electrically connected to the same selection line, and a first transistor is applied to the first pixel. A signal for reading out the information on the current characteristics of the third pixel is input to the third pixel. a function of performing a first operation of inputting a signal for indicating a current characteristic of the first transistor; a second operation of reading out the information from the pixel and inputting a data signal (video signal) to the second pixel; The semiconductor device has the function of performing the above.

[0015] Alternatively, in one embodiment of the present invention, in the above structure, the first transistor and the third transistor The sensors are electrically connected to the same wiring, and the information on the current characteristics is read out through the wiring. This is a semiconductor device that performs

[0016] Alternatively, in the above-described structure, one embodiment of the present invention is a method for detecting current characteristics of the first transistor. During the period when the readout is being performed, a data signal (video signal) is input to the second pixel. It is a semiconductor device.

[0017] Alternatively, in one embodiment of the present invention, in the above structure, information on the current characteristics is read by a second driving The semiconductor device operates from the period when the first pixel is selected until the next frame period. It is a body device.

[0018] Alternatively, in one embodiment of the present invention, in the above structure, the information on the current characteristics of the first transistor The semiconductor device is a semiconductor device in which the current flowing through the first transistor is a threshold voltage of the first transistor.

[0019] Another embodiment of the present invention is a semiconductor device including the above semiconductor device, a CPU, an image processing circuit, or a memory. , and is a display device having the same.

[0020] Another embodiment of the present invention is a semiconductor device or a display device including the above semiconductor device, a housing, a microphone, The electronic device has a touch panel, a speaker, or operation keys.

[0021] Other aspects of the present invention will be described in the following embodiments and is shown in the drawings. [Effects of the Invention]

[0022] One embodiment of the present invention is a novel semiconductor device, a novel display device, a method for driving the novel semiconductor device, Alternatively, a novel method for driving a display device can be provided.

[0023] Another embodiment of the present invention is a display device or the like that can perform external correction in parallel with a display operation. Alternatively, one embodiment of the present invention can provide a display device that performs external correction in parallel with a display operation. Alternatively, a driving method of a display device that can achieve the above can be provided. This makes it possible to provide a display device with little display unevenness and a method for driving the same. According to another aspect of the present invention, there is provided a display device capable of performing high-definition display, and According to another embodiment of the present invention, a driving method of a transistor can be provided. A semiconductor device capable of reducing the influence of characteristic variations and a driving method thereof are provided. Alternatively, according to one aspect of the present invention, the variation in threshold voltage of the transistor can be reduced. It is possible to provide a semiconductor device capable of reducing the influence of noise and a driving method thereof. Alternatively, according to one embodiment of the present invention, the influence of variations in the mobility of transistors can be reduced. It is possible to provide a semiconductor device that can achieve this and a method for driving the same.

[0024] The effects of one embodiment of the present invention are not limited to the effects listed above. This does not preclude the existence of other effects. Other effects are described below. The effects not mentioned in this section are obvious to those skilled in the art in the specification or This can be derived from descriptions in drawings, etc., and can be extracted appropriately from these descriptions. One aspect of the present invention is to achieve at least one of the effects listed above and / or other effects. Therefore, one aspect of the present invention is to provide the above-listed effects. It may not have any effect. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a timing chart illustrating one embodiment of the present invention. [Figure 2] 1 is a flowchart illustrating one embodiment of the present invention. [Figure 3] FIG. 1 is a block diagram illustrating one embodiment of the present invention. [Figure 4] FIG. 1 is a circuit diagram illustrating one embodiment of the present invention. [Figure 5] FIG. 1 is a circuit diagram illustrating one embodiment of the present invention. [Figure 6] FIG. 1 is a circuit diagram illustrating one embodiment of the present invention. [Figure 7] FIG. 1 is a circuit diagram illustrating one embodiment of the present invention. [Figure 8] FIG. 1 is a circuit diagram illustrating the operation of one embodiment of the present invention. [Figure 9] FIG. 1 is a circuit diagram illustrating the operation of one embodiment of the present invention. [Figure 10] FIG. 1 is a circuit diagram illustrating the operation of one embodiment of the present invention. [Figure 11] FIG. 1 is a circuit diagram illustrating the operation of one embodiment of the present invention. [Figure 12] FIG. 1 is a circuit diagram illustrating the operation of one embodiment of the present invention. [Figure 13]FIG. 1 is a circuit diagram illustrating the operation of one embodiment of the present invention. [Figure 14] FIG. 1 is a circuit diagram illustrating the operation of one embodiment of the present invention. [Figure 15] FIG. 1 is a circuit diagram illustrating one embodiment of the present invention. [Figure 16] FIG. 1 is a circuit diagram illustrating one embodiment of the present invention. [Figure 17] FIG. 1 is a circuit diagram illustrating one embodiment of the present invention. [Figure 18] FIG. 1 is a circuit diagram illustrating one embodiment of the present invention. [Figure 19] FIG. 1 is a circuit diagram illustrating one embodiment of the present invention. [Figure 20] FIG. 1 is a circuit diagram illustrating one embodiment of the present invention. [Figure 21] FIG. 1 is a circuit diagram illustrating one embodiment of the present invention. [Figure 22] FIG. 1 is a circuit diagram illustrating one embodiment of the present invention. [Figure 23] FIG. 1 is a diagram illustrating a layout of one embodiment of the present invention. [Figure 24] FIG. 1 is a block diagram illustrating one embodiment of the present invention. [Figure 25] FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 26] FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 27] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of the present invention. [Figure 28] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of the present invention. [Figure 29] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of the present invention. [Figure 30] FIG. 1 is a top view illustrating one embodiment of the present invention. [Figure 31] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of the present invention. [Figure 32] 1A and 1B are a top view and a cross-sectional view illustrating one embodiment of the present invention. [Figure 33] FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 34]1A and 1B are schematic diagrams illustrating band structures for explaining one embodiment of the present invention. [Figure 35] FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 36] FIG. 1 is a perspective view illustrating one embodiment of the present invention. [Figure 37] FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 38] FIG. 1 is a cross-sectional view illustrating one embodiment of the present invention. [Figure 39] FIG. 1 is a perspective view illustrating one embodiment of the present invention. [Figure 40] Electronic equipment illustration. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, embodiments will be described with reference to the drawings. It is possible to carry out the invention in various forms and in various ways without departing from the spirit and scope of the invention. It will be readily apparent to those skilled in the art that various modifications may be made to the design and details of the present invention. The present invention should not be construed as being limited to the following description of the embodiments.

[0027] In this specification, the ordinal numbers "first," "second," and "third" are used to indicate the mixture of constituent elements. Therefore, it does not limit the number of components. In addition, the order of the components is not limited. The element referred to as "first" in the above may be used in other embodiments or in the claims. In addition, for example, in the present specification, A component referred to as "first" in one embodiment may be used in other embodiments or in particular It may be omitted in the claims.

[0028] In the drawings, elements that are the same or have similar functions, elements that are made of the same material, or In some cases, the same reference numerals may be used to designate elements or components formed at the same time, and repeated explanations thereof will be omitted. It may be omitted.

[0029] In addition, when it is explicitly stated in this specification that X and Y are connected, is when X and Y are electrically connected and when X and Y are functionally connected. and the case where X and Y are directly connected are considered to be disclosed in this specification and the like. Therefore, the present invention is not limited to predetermined connection relationships, for example, connection relationships shown in drawings or text. Connections other than those shown in the text are also considered to be shown in the drawings or text.

[0030] Here, X and Y are the object (for example, a device, an element, a circuit, a wiring, an electrode, a terminal, a conductive film, a layer, etc.). , etc.).

[0031] An example of a direct connection between X and Y is a circuit that allows electrical connection between X and Y. The elements to be considered (e.g., switches, transistors, capacitance elements, inductors, resistance elements, When no external device (such as a diode, display element, light-emitting element, or load) is connected between X and Y, The elements that allow electrical connection between X and Y (e.g., switches, transistors, capacitors) elements, inductors, resistors, diodes, display elements, light-emitting elements, loads, etc.) , X and Y are connected.

[0032] An example of an electrical connection between X and Y is The elements to be considered (e.g., switches, transistors, capacitance elements, inductors, resistance elements, One or more devices (such as diodes, display elements, light-emitting elements, and loads) can be connected between X and Y. It is possible. The switch has a function to control on / off. A switch can be in a conducting state (ON state) or a non-conducting state (OFF state), allowing current to flow or not. Alternatively, the switch has the function of selecting the path through which the current flows and then switching it off. When X and Y are electrically connected, This includes cases where the

[0033] An example of a functional connection between X and Y is a function that allows the functional connection between X and Y. Circuits that perform the above functions (for example, logic circuits (inverters, NAND circuits, NOR circuits, etc.), signal conversion conversion circuits (DA conversion circuits, AD conversion circuits, gamma correction circuits, etc.), potential level conversion circuits (voltage power supply circuits (voltage boost circuits, voltage drop circuits, etc.), level shifter circuits that change the signal potential level, etc.) , voltage source, current source, switching circuit, amplifier circuit (circuit that can increase the signal amplitude or current amount, etc.) circuits, operational amplifiers, differential amplifier circuits, source follower circuits, buffer circuits, etc.), signal generation circuits One or more circuits (e.g., circuits, memory circuits, control circuits, etc.) can be connected between X and Y. For example, even if another circuit is inserted between X and Y, the signal output from X will If X is transmitted to Y, then X and Y are considered to be functionally connected. When X and Y are functionally connected, there are two cases: when X and Y are directly connected, and when X and Y are This also includes cases where the components are electrically connected.

[0034] In addition, if it is explicitly stated that X and Y are electrically connected, are electrically connected (i.e., there is another element or circuit between X and Y) X and Y are functionally connected (i.e., X and Y are functionally connected) and (When there is a functional connection between them via another circuit) and when X and Y are directly connected (i.e., when X and Y are connected without any other element or circuit between them) is considered to be disclosed in the present specification. If it is explicitly stated that it is connected, The same content is considered to be disclosed in the present specification.

[0035] For example, if the source (or first terminal, etc.) of the transistor is connected via Z1 (or (not shown), electrically connected to X, and the drain (or second terminal, etc.) of the transistor is connected to Z 2 (or not), and is electrically connected to Y, or the source of the transistor (or the first terminal, etc.) is directly connected to a part of Z1, and another part of Z1 is directly connected to X. The drain (or second terminal, etc.) of the transistor is directly connected to a part of Z2. and another part of Z2 is directly connected to Y, It is possible to do so.

[0036] For example, "X and Y and the source (or first terminal, etc.) and drain (or second terminal, etc.) of a transistor" The terminals of the transistor (or the first terminal) are electrically connected to each other. 1 terminal, etc.), the drain of the transistor (or the second terminal, etc.), and Y. It can be expressed as "connected to the source (or the first The first terminal of the transistor is electrically connected to X, and the drain of the transistor is electrically connected to the second terminal of the transistor. The transistor source (or first terminal, etc.) is electrically connected to Y, and the transistor source (or first terminal, etc.) is electrically connected to X. The drain (or second terminal, etc.) of the transistor, Y, is electrically connected in this order. " Alternatively, "X is the source (or first terminal, etc.) of the transistor. and the drain (or second terminal, etc.) are electrically connected to Y, and X, the source (or first terminal, etc.) of a transistor, the drain (or second terminal, etc.) of a transistor ), Y is provided in this order of connection. By specifying the order of connections in the circuit configuration using a simple expression method, Distinguish between the source (or first terminal, etc.) and the drain (or second terminal, etc.) of a transistor. The technical scope can be determined by the above.

[0037] Alternatively, for example, "the source (or first terminal, etc.) of a transistor" is electrically connected to X through at least a first connection path, and the first connection path is , and the second connection path is a transistor through a transistor. The source (or first terminal, etc.) of the transistor and the drain (or second terminal, etc.) of the transistor The first connection path is a path via Z1, and the second connection path is a path between the first and second transistors. The drain (or second terminal, etc.) of the capacitor is electrically connected to Y through at least a third connection path. the third connection path does not have the second connection path, and the third connection path The connection path is the path via Z2. The source (or first terminal, etc.) of the resistor is connected to the resistor via Z1 by at least the first connection path. and electrically connected to X, and the first connection path does not have a second connection path; The second connection path has a connection path through a transistor, and (or the second terminal, etc.) is connected to Y via Z2 by at least a third connection path. The third connection path does not have the second connection path. Alternatively, the source (or first terminal, etc.) of the transistor may be at least The first electrical path is electrically connected to X through Z1. The primary path does not have a second electrical path, and the second electrical path is a From the source (or first terminal, etc.) to the drain (or second terminal, etc.) of the transistor The drain (or second terminal, etc.) of the transistor is connected to at least a third The third electrical path is electrically connected to Y through Z2. , does not have a fourth electrical path, and the fourth electrical path is (or second terminal, etc.) to the source (or first terminal, etc.) of the transistor. Using the same expression as these examples, the circuit configuration By defining the connection path in Distinguishing between the first terminal (or the second terminal, etc.) and the drain (or the second terminal, etc.) to determine the technical scope. can be done.

[0038] These representation methods are merely examples, and the present invention is not limited to these representation methods. , Y, Z1, Z2 are objects (e.g., devices, elements, circuits, wiring, electrodes, terminals, conductive films, layer, etc.).

[0039] In addition, the circuit diagram shows independent components as if they are electrically connected to each other. Even if the components are different, one component may have the functions of multiple components. For example, when a part of the wiring also functions as an electrode, one conductive film functions as both the wiring and the electrode. Therefore, the electrode in this specification has the functions of both components. The term "electromagnetic connection" refers to a case where one conductive film has the functions of multiple components. This also falls within the scope of the above.

[0040] (Embodiment 1) In this embodiment, a structure and a driving method of a semiconductor device according to one embodiment of the disclosed invention will be described. This will be explained with reference to FIGS. 1 to 23.

[0041] <External correction method> The display device described in this embodiment is a matrix of m rows and n columns (both m and n are integers of 2 or more). The pixel includes a plurality of pixels arranged in a square shape. The transistor (hereinafter also referred to as a driving transistor) supplies a current to the It is possible to read out information on the current characteristics of the driving transistor to the outside of the pixel portion where the pixel is provided. The circuit has a function to read the current (hereinafter also referred to as a read circuit). The current value when a predetermined voltage is supplied to the driving transistor, or the Examples include the threshold voltage of a transistor or a voltage corresponding to the threshold voltage. The readout circuit is connected to the display device and the FPC (Flexible Printed Circuit) Printed Circuit) or may be provided in the display module. do.

[0042] The readout circuit may, for example, read information from the pixel, such as a potential or a current. However, the readout circuit may have other functions, such as For example, the readout circuit may have a function of supplying a predetermined potential to the pixel. Alternatively, for example, the readout circuit may have the function of storing information. Alternatively, for example, the readout circuit has the function of converting an analog signal into a digital signal. Therefore, the readout circuit may be simply called a circuit. The circuit may be referred to as a first circuit, a second circuit, etc.

[0043] A transistor such as a driving transistor is, for example, a transistor that drives a display element such as a light-emitting element. Alternatively, a transistor such as a driving transistor may have a function of: As an example, a function that can control the amount of current flowing through a display element such as a light-emitting element is known. However, transistors such as driver transistors may have other functions, for example. Therefore, transistors such as driving transistors are sometimes simply referred to as transistors. For example, a transistor such as a driver transistor may be called a first transistor. It may be called a first transistor, a second transistor, etc.

[0044] As shown in FIG. 1, the display device shown in this embodiment is configured such that the first to m-th rows are sequentially arranged. The image is displayed by scanning the pixels repeatedly. This shows the operation of the display device during a frame period. After starting scanning of a specific row, scanning of m rows is performed sequentially. The time it takes to scan a specific row and then scan the next row is called one frame period. There is a period in which scanning to display an image is not performed (hereinafter also referred to as a blanking period). The period from the start of scanning the first row to the mth row is called the address. In other words, one frame period is the However, one frame period may be composed of a dressing period and a blanking period. In some cases, the frame may have multiple subframe periods. In this case, each subframe period has its own Each row may have an address period. Also, pixels belonging to a certain row are selected and the corresponding A signal (hereinafter also referred to as a data signal) that controls the light emission of the light emitting element in the pixel is input, In the next frame period, the pixel is selected again and a new data signal is input. The period from when the pixel is turned on to when the The period during which the gradation is displayed is sometimes called the display period. A signal for selecting the pixel (hereinafter, referred to as a selection line) is applied to a wiring connected to the pixel. The length of the display period can be determined by supplying a selection signal. Although it is the same for all rows, the timing when the display period starts and ends varies depending on the row. Things often change depending on the situation.

[0045] While scanning to display an image, the current characteristics of the driving transistor are read out. If you try to do this, the image display may be distorted due to the input of a readout signal. However, all the pixels in the m×n array, all the pixels of a particular color in the m×n array, or When a specific number of pixels are all displayed in black, the pixel is selected and the current characteristic information is By reading out the current characteristics, the information can be read out without disturbing the black display of the pixel. It should be noted that the case where a specific number of pixels are all displayed in black specifically means that the same When all pixels connected to one selection line are displayed in black, all pixels arranged in the same row are displayed in black. When all pixels in a row are displayed in black, or when all pixels of a specific color are displayed in the same row, For example, when the pixels belong to the same row and are connected to the same selection line, For example, all the connected pixels are displayed in black.

[0046] The black display state may also be called a non-display state. This is sometimes called a state where the number of gradations is zero. The state in which the display is in a state where the screen is in a state where ... The state where the number of gradations is greater than zero is sometimes called the state where the number of gradations is greater than zero. The state where the display is in white is sometimes called the white display state. The state in which the lowest gradation is displayed is sometimes called the state of displaying at the highest number of gradations. .

[0047] In this embodiment, as an example, when a specific plurality of pixels are all displayed in black, Among the plurality of pixels, the current characteristics of the driving transistor of a predetermined pixel are By reading out the information, the variation in the current characteristics of the driving transistor is corrected. A method for driving the display device will now be described.

[0048] FIG. 2 shows an example of a flowchart of a method for driving a display device described in this embodiment. As shown, the method for driving the display device will be explained by dividing it into steps S1 to S6.

[0049] First, when the address period starts, a specific pixel is selected (step S1). This can be done using a gate line driving circuit or the like. If all the pixels are displayed in black (YES in step S2), Among them, the predetermined pixels (hereinafter also referred to as readout pixels) that read out information on the current characteristics are: A signal for reading out information on the current characteristics (hereinafter also referred to as a read signal) is input. In addition, among the specific plurality of pixels, the pixels other than the read pixels are supplied with a signal for displaying black. In this example, the specific pixels are input as follows (step S3). The case where n pixels are connected to the same selection line and belong to the same row will be explained. By reading out information only from the readout pixels, the information is prevented from being mixed up. This can be avoided.

[0050] In step S3, the readout signal is input, and the drive transistor is read out from the readout pixel. The information on the current characteristics can be read out using a read circuit. The information may be read during the operation of step S3, or after the operation of step S3. It may be carried out after the production period.

[0051] The information on the current characteristics includes information on the variations in the current characteristics of the driving transistors. For example, it may be the current value of the driving transistor, or It is also possible to use the threshold voltage of the transistor for the current detection. At least one of the threshold voltage, mobility, channel length, or channel width is For example, you can see if the quality is fluctuating or deteriorating. When the information to be read is a current value, the current is proportional to the magnitude of the input read signal. It has a size according to the

[0052] When the readout signal is input in step S3, the light emitting element of the readout pixel It is preferable that a reverse bias be applied to the light emitting element so that the black display can be maintained. In addition, even if a forward bias is applied, the black display state can be maintained. The potential difference should be kept to a weak level. A weak potential difference of a few volts or less is preferable. For example, it is set to 2 volts or less, more preferably 1 volt or less. It is preferable that no current flows between the light emitting element and the The transistor connected to the light emitting element is turned off, and as a result, no current flows through the light emitting element. It is preferable that the temperature is in a stable state.

[0053] On the other hand, if at least one of the n pixels belonging to the same row is not displayed in black (step S 2) "NO" does not input a read signal, and displays a predetermined gradation in n pixels. A signal for performing the write operation is inputted, and a normal write operation is performed (step S4).

[0054] If the gate line driving circuit has a shift register circuit, the first to mth rows It is possible to scan each row in order. Also, as a gate line driving circuit, a decoder circuit etc. If a .xls or .yls is used, any row can be selected in any order. In this case, the gate line driving circuit does not need to scan each row in order from the first row to the mth row. Without scanning, only the specified rows (rows with black display) are selected immediately and the readout signal is sent to the pixels. The number of lines to be selected may be one or more. .

[0055] Then, in step S3, after inputting the readout signal and the black display signal, the next line of the image is The pixel is selected and the information on the current characteristics of the driving transistor of the read pixel is read. At this time, for example, in the read pixel, the current characteristics of the transistor are The switch or transistor for reading is in the on state. In writing, as in step S2, it is determined whether a specific pixel is displayed in black, and Simply input the signal.

[0056] The information on the current characteristics is read out again in the next frame period after step S3. This can be done freely during the period until the next pixel is selected for reading. As in step S5, when a row is selected during the address period, the information on the current characteristics is The following can be read out.

[0057] For example, as shown in FIG. 1A, in the pixel in the i-th row (i is an integer between 1 and m), Over the entire display period, that is, over one frame period, the driving current of the read pixel is It is possible to read out information on the current characteristics of the driving transistors. In the shortest possible time, information on the current characteristics of the driving transistor of the read pixel is read. For example, as shown in FIG. 1(B), after the read pixel is selected, The readout may be performed during part or all of the dressing period, or as shown in FIG. 1(C). As shown in FIG. 1(D), the readout may be performed during part or all of the blanking period. ) in the next address period, a part of the time until the readout pixel is selected or It is also possible to read out the characteristics of the pixels in the i-th row. If not, the display will be over the entire display period, i.e., over one frame period. An action is performed.

[0058] In step S5, if a readout signal is held in the readout pixel, However, it is not necessary to continuously input a readout signal to the pixel.

[0059] On the other hand, if normal writing is performed in step S4, only the selection of pixels in the next row is performed. (Step S6).

[0060] After the pixels in the next row are selected in step S5 or step S6, the pixels in the next row are Depending on whether all the pixels are displayed in black (step S2), steps S3 to S The operation of step S3 is performed in the same manner as step S6. In the case of the pixel in the 3rd row, there may be a blanking period between steps S3 and S5. Alternatively, information on the current characteristics may be read out during the blanking period.

[0061] Also, the number of rows to be read out during one frame period does not have to be only one. During a frame period, the readout operation may be performed on multiple rows. For example, A read operation is performed on the i-th row, the i+A-th row, and the i+A+B-th row in FIG. Here, A and B are natural numbers. The operations up to step 6 are repeated for the number of rows during one frame period.

[0062] Then, in the next frame period, the information on the current characteristics read out after step S3 is A signal in which the variations in the current characteristics have been corrected is created according to the above, and the signal is read out and input to the pixel. It is possible.

[0063] The information on the current characteristics is read out by, for example, measuring the voltage of a transistor in a read pixel. The switch or transistor for reading the current characteristics is turned off. It is possible.

[0064] This allows external correction to be performed in parallel with the display operation. This makes it possible to realize a display device with less display unevenness. This makes it possible to realize a display device that can achieve the above. This makes it possible to realize a semiconductor device that can reduce the influence of the transistor. A semiconductor device capable of reducing the influence of variations in threshold voltage of a transistor can be realized. This can also reduce the effect of variations in transistor mobility. A semiconductor device can be realized.

[0065] In addition, for a row in which all pixels have never been displayed in black since the image began to be displayed, For example, when the power supply of the display device is turned off, immediately after the power supply of the display device is turned on, When the display device is not in use during the period, at least one of late night and early morning It is preferable to read out information on the current characteristics of the driving transistors in the row. There is a period during a frame or sub-frame where all pixels are displayed in black. There may be cases where all pixels are displayed in black between one frame period and another. If there is a period, or if all images are If there are periods when the pixel is displayed in black, the current of the driving transistor The characteristic information can be read out.

[0066] Using the above driving method, the variation in the current characteristics of the driving transistors of each pixel of the display device is In this driving method, the driving voltage is adjusted in parallel with the display operation of the display device. The variations in the current characteristics of the transistors can be corrected.

[0067] This allows pre-shipment inspection of a product incorporating a display device according to one embodiment of the disclosed invention. When inspecting the product, the product's display is inspected and the luminance of the pixels is corrected. This allows the inspection period before shipping of the product to be shortened, Cost reduction can be achieved.

[0068] Furthermore, the above-described driving method of the display device is also effective in turning on the power and displaying an image even after the product has been shipped. This is done every time the display is displayed. Therefore, there is no variation in the luminance due to deterioration over time after product shipment. This allows for automatic correction of the product's wear, thereby extending its lifespan. It is possible.

[0069] In the above-described method for driving a display device, the current characteristics are changed while displaying on other rows. However, the driving method of the display device shown in this embodiment does not necessarily read out the information on the characteristics. For example, when the display screen goes dark and all pixels are displayed in black, Or, when inserting a black screen to improve the video characteristics, Information may be read out.

[0070] <Configuration Example of Semiconductor Device> Next, a specific example of a configuration of a semiconductor device according to one embodiment of the disclosed invention will be described with reference to the block diagram of FIG. The following description will be given using the block diagram and the circuit diagram of FIG. 4. FIG. 3 shows a block diagram of a pixel array having (m×n) pixels 20. 1 is an example of a block diagram of a pixel unit 15 and peripheral circuits.

[0071] The display device shown in FIG. 3 includes a driving circuit 11, a driving circuit 12, a circuit section 13, and pixels 20 arranged vertically. The pixel section 15 is arranged in a matrix of m rows by n columns, and extends in the row direction. The wirings SL_1 to SL_m are provided, and the wirings GL_1 to GL_m are provided extending in the row direction. GL_m, wirings DL_1 to DL_n extending in the column direction, and wirings DL_2 to DL_n extending in the row direction. The wirings IL_1 to IL_m are provided in this manner. Since the wirings IL are arranged in the row direction, the wirings IL can be driven independently in each row. Therefore, the current characteristic information can be read out independently for each row. Therefore, in one frame period, the information on the current characteristics is read out for multiple rows. This can be done.

[0072] The driving circuit 11 is connected to the wirings SL_1 to SL_m and the wirings GL_1 to GL_m. The driving circuit 11 has a function of selecting a pixel or a row. The driving circuit 11 has a function of sequentially selecting pixels or rows one by one. , has the function of selecting a specific pixel or row. The driving circuit 11 has a function of outputting a selection signal or a non-selection signal. It has a function as a gate line driving circuit or a scan line driving circuit.

[0073] The driving circuit 12 is connected to the wirings DL_1 to DL_n. , and has a function of supplying data signals to the pixels or columns. The driver circuit 12 has a function of supplying a read signal to the pixel or column. functions as a source line driver circuit, a data line driver circuit, or a video signal line driver circuit An example of a data signal is a signal corresponding to an image to be displayed on a pixel (hereinafter referred to as a pixel signal). (also called video signal below).

[0074] The circuit section 13 (hereinafter also referred to as a read circuit section) is connected to the wirings IL_1 to IL_m. The circuit section 13 has a function of reading information output from the pixels. The circuit unit 13 has a function of reading the potential of the terminal in the pixel. has the function of selecting whether or not to read the information output from the pixel.

[0075] The drive circuit 12 and the circuit section 13 can also be integrated into one circuit.

[0076] In this way, the drive circuit 11, the drive circuit 12, the circuit unit 13, etc. may have various functions. Therefore, the drive circuit 11, the drive circuit 12, the circuit section 13, etc. will be simply called a circuit. For example, the drive circuit 11, the drive circuit 12, the circuit unit 13, etc. may be referred to as a first circuit, a second circuit, etc. It is sometimes called circuit 2.

[0077] FIG. 4 shows the configuration of pixel 20_(i,j) in row i, column j (j is an integer between 1 and n). 20_(i,j) is a transistor 21, a transistor 22, a transistor 23, a light-emitting element The transistors have a multi-gate element 24 and a capacitance element 25. It may have a structure in which multiple transistors are connected in series. Each transistor has a gate electrode above and below the channel. These elements of the pixel 20_(i, j) may be connected to the wiring GL_ i, wire SL_i, wire DL_j, wire CL_j, and wire IL_i are connected to the Although the wirings CL_1 to CL_n are not shown in FIG. For example, the wiring CL can be provided extending in the column direction. However, the present invention is not limited to this, and the extending direction may be changed as appropriate. For example, the wiring may be arranged in the column direction and the wiring in the row direction, and the wiring may be connected to each other. good.

[0078] In addition, for pixels 20 other than pixel 20_(i,j), the same It can be configured as follows.

[0079] The specific connection relationship of the pixel 20_(i,j) is as follows: The port is connected to the wiring GL_i, and either the source or the drain is connected to the wiring DL_j. The other of the source and drain is connected to the gate of transistor 22. One of the source and drain of the transistor 22 is connected to the wiring CL_j. The other of the two terminals is connected to one of the source and drain of the transistor 23 and one of the light emitting elements 24. The gate of the transistor 23 is connected to a wiring The other of the source and drain is connected to the wiring IL_i. The other electrode of the optical element 24 (hereinafter also referred to as a common electrode) is applied with a predetermined potential (hereinafter referred to as a common potential (also called) is given.

[0080] The wiring IL_i is connected to a read circuit 16 included in the circuit unit 13. , the wiring IL_i is connected to the line IL_i during the period when the information of the current characteristics is not read out or when the video signal or During the period when the readout signal is supplied to the pixel, another circuit, for example, a circuit that supplies a constant potential, For example, the wiring IL_i may be connected to a circuit that has a function of providing a constant potential. The wiring IL_i may be connected to the read circuit 16 and the wiring IL_i. When the line IL_i is connected to another circuit 17, as shown in FIG. A switch 19a is set between the circuit 16, and a switch 19b is set between the wiring IL_i and the circuit 17. Then, by switching each switch, the wiring IL_i and the readout circuit It is possible to establish electrical continuity between the circuit 16 and the circuit 17. The circuit 17 may be a circuit provided inside the circuit section 13 in FIG. It may be a circuit provided outside the device.

[0081] One electrode of the capacitor 25 is connected to the other of the source and drain of the transistor 21. and the gate of transistor 22, and the other electrode is connected to the source or the other of the drain, one of the source or drain of the transistor 23, and the light-emitting element 2 In this way, the capacitance element 25 is provided, and the transistor This allows a large amount of charge to be stored in the gate of the transistor 22, thereby extending the retention period of image information. It is possible.

[0082] The capacitor 25 is not necessarily provided. For example, the capacitor 25 may be provided at the gate of the transistor 22. If the parasitic capacitance between the source or the drain of the transistor 22 and the other is large, The capacitive element 25 can be replaced by a parasitic capacitance.

[0083] The driving circuit 11 controls the on and off states of the transistor 21 via the wiring GL. Thus, the on and off states of the transistor 23 can be controlled via the wiring SL. Cut.

[0084] The driving circuit 12 transmits a video signal or a read signal to the gate of the transistor 22 via the wiring DL. can be given to the

[0085] The circuit unit 13 has readout circuits 16 corresponding to the wirings IL_1 to IL_m. The readout circuit 16 can read out information about the current characteristics from the transistor 22 of each pixel 20. Alternatively, the read circuit 16 may supply a predetermined voltage to the lines IL_1 to IL_m. It is possible.

[0086] The wiring CL functions as, for example, a high-potential power supply line that supplies current to the light-emitting element 24. can be done.

[0087] However, the configurations of the drive circuit 11, the drive circuit 12 and the circuit section 13 are not limited to those described above. The positions at which the drive circuits 11, 12 and the circuit section 13 are provided may be changed. The functions of a plurality of these driving circuits may be integrated into one driving circuit. For example, in FIG. 3, the drive circuit 11 and the circuit section 13 are provided on only one side of the pixel section 15. , the drive circuit 11 or the circuit section 13 is divided and provided on both sides of the pixel section 15. In addition, in FIG. 3, the drive circuit 11 and the circuit section 13 are provided separately, but they may be integrated. Alternatively, the drive circuits may be integrated into one drive circuit unit.

[0088] In addition, the positions, functions, and other configurations of the drive circuit 11, the drive circuit 12, and the circuit section 13 are changed. Accordingly, the extending directions of the wiring GL, wiring SL, wiring DL, wiring IL and wiring CL, For example, the wiring IL may be configured to extend in the column direction. Also, for example, the wiring GL and the wiring SL may be combined into one type of wiring. The circuit diagram for this case is shown in Figure 6. When using a single type of wiring, Therefore, transistor 21 and transistor 23 are turned on and off at the same time. When a driving method is adopted in which the transistor 1 and the transistor 23 are turned on and off simultaneously, GL and wiring SL can be combined into one type of wiring.

[0089] The magnitude of the current flowing through the light emitting element 24 depends on the magnitude of the video signal input to the pixel 20. The luminance of the light-emitting element 24 is controlled according to the transistor 22. It is determined by the amount of current flowing between the pixel electrode and the common electrode. For example, OLED (organic light-emitting diode) When a light emitting element 24 is used, either the anode or the cathode is connected to the pixel. In FIG. 4, one electrode functions as an anode of the light-emitting element 24, and the other electrode functions as a common electrode. as a pixel electrode and the cathode of the light-emitting element 24 as a common electrode. is shown as an example.

[0090] Note that the polarity of the transistor, the orientation of the light-emitting element, the potential of the wiring, the potential of the signal, etc. may be changed. It is also possible to operate with a modified circuit configuration. For example, a modified version of Figure 4 is shown in Figure 7. In FIG. 7, the transistors 21 to 23 are p-channel transistors, and the light-emitting element 24 is oriented in the opposite direction to that shown in FIG. 4. In addition to the pixel circuit shown in FIG. It can be configured.

[0091] The transistors 21 to 23 and other transistors included in the pixel 20 At least one of the transistors includes a transistor having an oxide semiconductor in a channel formation region (hereinafter, In particular, an OS transistor (also called an OS transistor) can be used as the transistor 21. By using a transistor, the off-state current of the transistor 21 can be made extremely small. By using such a transistor 21 in the pixel 20, it is possible to When a transistor formed of a semiconductor such as silicon or germanium is used as the transistor 21, Compared with the above, leakage of the charge stored in the gate of the transistor 22 or the capacitor element 25 can be prevented. You can do this.

[0092] Also, like a still image, the same image is displayed on the pixel section 15 over several consecutive frame periods. When a video signal having information is written, the driving frequency is lowered. Even if the number of times that a video signal is written to the pixel unit 15 within a certain period is reduced, the image display For example, the absence of electron donors such as water or hydrogen can be prevented. A highly purified oxide semiconductor in which impurities are reduced and oxygen vacancies are reduced. (purified oxide semiconductor) in transistor 21 By using the semiconductor film, the interval between writing of the video signal can be set to 10 seconds or more, preferably 30 seconds or more. It is more preferable that the time period be 1 minute or more. The longer the interval, the more power consumption can be reduced.

[0093] In addition, the potential of the video signal can be held for a longer period of time. Even if the pixel 20 does not have a capacitance element 25 for maintaining the potential of the gate of the pixel 22, the display This can prevent the image quality from deteriorating.

[0094] Note that the structure and off-state current of an OS transistor will be described in detail later in Embodiment 4. do.

[0095] The transistors 21 to 23 and other transistors are OS transistors. For example, a transistor in which a channel formation region is formed on a substrate having a single crystal semiconductor A transistor formed in the region of the single crystal semiconductor can be used. Examples of the substrate include a single crystal silicon substrate and a single crystal germanium substrate. Since transistors having single-crystal semiconductors have high current supply capabilities, By configuring the pixel 20 using .

[0096] The transistors 21 to 23 and other transistors are OS transistors. A transistor other than a transistor in which a channel formation region is formed in a semiconductor film For example, a transistor having a non-single-crystal semiconductor in a channel formation region can be used. The non-single-crystal semiconductor can be made of amorphous silicon or microcrystalline silicon. , non-single-crystal silicon such as polycrystalline silicon, amorphous germanium, microcrystalline germanium and non-single-crystal germanium such as polycrystalline germanium. By using a semiconductor film having such a property, the operation speed of the pixel 20 can be improved.

[0097] Furthermore, each transistor only needs to have a gate on at least one side of the semiconductor film. However, it may have a pair of gates sandwiching a semiconductor film therebetween.

[0098] Here, a transistor T has a pair of gates sandwiching a semiconductor film therebetween. In this case, a signal A may be applied to one gate and a fixed potential Vb may be applied to the other gate. .

[0099] The signal A is, for example, a signal for controlling the conductive state or the non-conductive state. It is a digital signal that takes on two types of potential: potential V1 or potential V2 (V1>V2). For example, the potential V1 may be set to a high power supply potential, and the potential V2 may be set to a low power supply potential. Signal A may be an analog signal.

[0100] The fixed potential Vb is, for example, a potential for controlling the threshold voltage VthA of the transistor T. The fixed potential Vb may be the potential V1 or the potential V2. This is preferable because it is not necessary to provide a separate potential generating circuit for generating the potential Vb. The fixed potential Vb may be a potential different from the potential V1 or the potential V2. As a result, the gate-source voltage V The drain current when gs is 0V is reduced, and the leakage current of the circuit with transistor T is For example, the fixed potential Vb may be set lower than the low power supply potential. Increasing the potential Vb may result in a lower threshold voltage VthA. Improve the drain current when the gate-source voltage Vgs is VDD, and For example, if the fixed potential Vb is set higher than the low power supply potential, the operating speed of the circuit can be improved. It may be higher than that.

[0101] Also, signal A is given to one gate of transistor T, and signal B is given to the other gate. The signal B may be used to control the conducting or non-conducting state of the transistor T, for example. Signal B has two types of potentials: potential V3 and potential V4 (V3>V4). For example, the potential V3 is a high power supply potential, and the potential V4 is a digital signal. may be at a low power supply potential. Signal B may be an analog signal.

[0102] If signal A and signal B are both digital signals, signal B has the same digital value as signal A. In this case, the on-current of the transistor T is improved, and the transistor T In this case, the potential V1 of signal A is higher than the potential V2 of signal B. The potential V2 of the signal A may be different from the potential V4 of the signal B. For example, the gate insulating film corresponding to the gate to which the signal B is input may be If the gate insulating film is thicker than the gate insulating film corresponding to the input gate, the potential amplitude of signal B (V3-V 4) may be made larger than the potential amplitude (V1-V2) of signal A. The effect of signal A on the conduction or non-conduction state of transistor T and the effect of signal B on the conduction or non-conduction state of transistor T are In some cases, the impact can be considered to be the same as that of

[0103] If signal A and signal B are both digital signals, signal B will have a different digital value than signal A. In this case, the control of the transistor T is performed by the signal A and the signal B separately. For example, if a transistor T In the case of an n-channel type, when signal A is at potential V1 and signal B is at potential V3 When only signal A is in a conducting state, or when signal B is at a potential V4, If the transistor is in a non-conducting state only when the NAND circuit or NOR circuit is turned on, In addition, the signal B may be used to control the threshold voltage VthA. For example, signal B may be a signal when a circuit including transistor T is operating. Signal B may be a signal whose potential is different between the period when the circuit is in operation and the period when the circuit is not in operation. In this case, signal B may be a signal whose potential varies depending on the operation mode of the circuit. The potential may not switch as frequently as in No. A.

[0104] If both signal A and signal B are analog signals, signal B is an analog signal with the same potential as signal A. signal, an analog signal obtained by multiplying the potential of signal A by a constant, or by adding a constant to the potential of signal A. In this case, the on-current of the transistor T is This may improve the operating speed of the circuit having the transistor T. In this case, the control of the transistor T is the same as the signal A. This can be done separately by signal B, which may allow for higher functionality.

[0105] Signal A may be a digital signal and signal B may be an analog signal. Signal B may be a digital signal.

[0106] Also, one gate of the transistor T is connected to a fixed potential Va, and the other gate is connected to a fixed potential V b may be applied. If both gates of the transistor T are applied with a fixed potential, There are cases where a resistor T can function as an element equivalent to a resistor element. For example, When the transistor T is an n-channel type, the fixed potential Va or the fixed potential Vb is set high (low) By reducing the resistance, it may be possible to lower (increase) the effective resistance of the transistor. By making both the fixed potential Va and the fixed potential Vb high (low), a transistor having only one gate can be obtained. In some cases, a lower (higher) effective resistance can be obtained than that obtained by a larger transistor. be.

[0107] In addition, FIG. 4 illustrates a case where all the transistors are n-channel type. If all the transistors in 0 have the same channel type, Therefore, it is possible to omit some steps such as adding impurity elements that give the semiconductor film one conductivity. However, in a display device, not all transistors in the pixel 20 are necessarily n-channel. For example, the transistors 21 and 23 may be p-channel. It can also be set to

[0108] Also, instead of the transistors 21 and 23, an electrical switch, a mechanical switch, or the like may be used. A switch, a MEMS element, or the like may also be used.

[0109] <Method of Driving a Semiconductor Device> Next, an example of a method for driving the semiconductor device shown in FIGS. The operation of nine pixels including pixel 20_(i,j) in row i and column j is shown in FIGS. 8 to 14. In the following, the pixel selected in step S1 of FIG. , the pixel 20 in the i-th row connected to the same wiring GL_i and the same wiring SL_i. In addition, the case where all the pixels 20 in the i-th row are displayed in black and the pixel in the i-th row and j-th column is displayed in black is described. The case where information on the current characteristics is read from 20_(i,j) will be explained. _i, the readout circuits 16 connected to the wiring IL_i+1 and the wiring IL_i+2 are respectively They are represented as read circuit 16_i, read circuit 16_i+1, and read circuit 16_i+2.

[0110] First, when the address period of one frame period starts, the first row to the mth row are sequentially Then, as shown in FIG. 8, when the pixel 20 in the i-th row is selected, A selection signal is input to the wiring SL_i, and the transistor 23 is turned on in the pixel 20 in the i-th row. When the transistor 23 is turned on, the wiring IL_i and the transistor 22 The other of the source and drain of the transistor 22 (hereinafter also referred to as the source electrode of the transistor 22) is conductive. The potential of the wiring IL_i is applied to the source electrode of the transistor 22. The selection signal input to the _i is that the transistor 23 is an n-channel transistor. When the transistor 23 is a p-channel transistor, can use a low level potential.

[0111] At this time, the potential of the wiring IL_i is set to a potential that does not cause the light emitting element 24 to emit light. Specifically, the potential of the wiring IL_i is lower than the common potential of the light-emitting element 24, or It is preferable to set the potential of the wiring IL_i to the same level as the common potential. By this, a reverse bias is applied to the light emitting element 24 or a state where no bias is applied is This allows the pixels in the i-th row to maintain a black display state. The arrangement is such that the black display state can be maintained even if a forward bias is applied to the transistor 24. It is preferable to suppress the potential difference between the line IL_i and the common potential to a small potential difference. The voltage is preferably a few volts or less, for example, 2 volts or less, more preferably 1 volt or less. The maximum is 1000.

[0112] It should be noted that the operation shown in FIG. 8 does not necessarily have to be performed.

[0113] After that, or at the same time as the selection signal is input to the wiring SL_i, the selection signal is input to the wiring GL_i. The transistor 21 in the pixel 20 in the i-th row is turned on (FIG. 9). When the transistor 21 is turned on, the wiring DL and the gate electrode of the transistor 22 are in a conductive state. Here, the wiring DL_j+1 and the wiring DL_j+2 are connected to the pixel 20_(i, j+1), and a video signal (here, a video signal for black display) for pixel 20_(i, j+2) is given. Therefore, the gate electrode of the transistor 22 of the pixel 20_(i, j+1) is connected to the gate electrode of the transistor 22 of the pixel 20_(i, j+1). A potential corresponding to the video signal of pixel 20_(i,j+1) is applied, and the potential of pixel 20_(i,j+2) is applied. A potential corresponding to the video signal of pixel 20_(i, j+2) is applied to the gate electrode of transistor 22. That is, a voltage is obtained between the gate and source of the transistor 22 of the pixel 20_(i, j+1). , a voltage between the potential of the wiring DL_j+1 and the potential of the wiring IL_i is supplied. Between the gate and source of the transistor 22 of 20_(i, j+2), the potential of the wiring DL_j+2 is applied. A voltage between the potential of the line IL_i and the potential of the line IL_i is supplied. The potential difference between the gate and source of the transistor 22 is stabilized, and the gate electrode of the transistor 22 or the capacitor element 25 A current corresponding to the held video signal can be supplied to the light emitting element 24 from the wiring CL_j. In FIG. 9, the pixel 20_(i, j+1) and the pixel 20_(i, j+2) Since a video signal corresponding to black display is applied to the gate of the transistor 22 of the transistor The signal GL_i is selected from the selection signals GL_i, ... When the transistor 21 is an n-channel transistor, a high-level potential is used. When the transistor 21 is a p-channel transistor, a low-level potential can be used.

[0114] On the other hand, a read signal is applied to the line DL_j. When a selection signal is input and the transistor 21 of the pixel 20_(i, j) is turned on, A read signal is applied to the gate electrode of the transistor 22, turning the transistor 22 on. Here, a selection signal is input to the wiring SL_i, and the transistor 23 is in an on state. Therefore, the wiring IL_i and the source electrode of the transistor 22 are electrically connected, and the transistor 22 The potential of the wiring IL_i is applied to the source electrode of the transistor CL_j. The read circuit 16_i is electrically connected to the line 22 and the transistor 23. The potential of the line IL_i is controlled by the readout circuit 16_i. Therefore, the pixel 20_(i, j) maintains the black display state. In addition, information on the current characteristics of the transistor 22 can be read out. The potential can be set by the read circuit 16_i.

[0115] Here, the information on the current characteristics of the transistor 22 is Any information about the variation in the current characteristics of a transistor may be used. It may be the current value of the transistor 22 or the threshold voltage of the transistor 22.

[0116] Here, for rows other than row i, the transistors are set to prevent the readout signal from being input. A signal that keeps the inverter 21 in the OFF state is input to the wiring GL.

[0117] In addition, when the wiring GL_i and the wiring SL_i are combined into one, The same operation as when the wiring SL_i is selected at the same time is performed.

[0118] Next, as shown in FIG. 10, the selection of the pixel 20 in the i-th row is completed, and the selection of the pixel 20 in the i+1-th row is completed. When the pixel in the i+1th row is selected, the wiring GL_i+1 and the wiring SL_ On the other hand, the selection signal input to the wiring GL_i is supplied to As a result, the transistor 21 is turned off. The selection signal is supplied to the wiring GL_i+1 and the selection signal is supplied to the wiring SL_i+1. The selection signals may be applied at different times as shown in FIGS.

[0119] Here, in the pixel 20_(i, j+1) and the pixel 20_(i, j+2), the transistor Since the potential difference between the gate and source of the pixel 20_(i, j+1) is maintained, No current flows through the transistor 22 in the pixel 20_(i, j+2), and the light emitting element 24 As a result, no current flows through the pixel 20_(i,j+1) and the pixel 20_(i,j+2). The light emitting element 24 is maintained in a black display or non-display state. The read circuit 16_i is in a non-conductive state, and the wiring CL_j+2 and the read circuit 16_i are It becomes non-conductive.

[0120] On the other hand, in the pixel 20_(i, j), a read signal is stored in the gate of the transistor 22. Since the line SL_i Since the selection signal is supplied to the transistor 23, the transistor 23 is maintained in the on state. Therefore, even during the period when the pixel 20 in the i+1th row is selected, the pixel 20_(i,j) The information on the current characteristics of the transistor 22 can be read out by the read circuit 16_i. At this time, the potential of the wiring IL_i is controlled by the read circuit 16_i. No current flows through the light emitting element.

[0121] As described above, the transistor 23 of the pixel 20_(i,j) is connected when the pixel 20 in the i-th row is selected. It is preferable that the pixel 20 in the i-th row is kept in the on state even after the end of the selection. Furthermore, the information on the current characteristics can be read out even after the selection of the pixel 20 in the (i+1)th row. That is, during the period when the information on the current characteristics of the pixels 20 in the i-th row is being read out, In this case, data signals can be input to other pixels 20 in the (i+1)th row, etc. In this case, the wiring SL_i continues to be connected to the transistor 23 even after the pixel 20 in the (i+1)th row is selected. In this case, for example, a signal that turns on the wiring SL must be continuously input. A switching circuit is connected, and the input signal when the pixel 20 in the i-th row is selected is converted to the input signal when the pixel 20 in the i+1-th row is selected. It would be better if the data could be retained thereafter.

[0122] In addition, when a decoder circuit or the like is adopted in the gate line driving circuit, the wiring S Even if you do not connect a latch circuit to L, you can control the signal input to the decoder circuit. Therefore, it is possible to continue supplying the selection signal to the wiring SL_i.

[0123] In FIG. 10, the pixel 20_(i+1,j) which is the pixel in the i+1th row, the pixel 20_ A normal video signal is supplied to pixel 20_(i+1,j+1) and pixel 20_(i+1,j+2). .

[0124] Next, as shown in FIG. 11, the selection of pixel 20 in the i+1th row is completed, and pixel 2 in the i+2th row is selected. When the pixel in the (i+2)th row is selected, the wiring GL_i+2 and the wiring S A selection signal is supplied to pixel 20_(i+2,j), pixel 20_( A video signal is supplied to pixel 20_(i+2, j+1) and pixel 20_(i+2, j+2). The selection signal that was input to the wiring GL_i+1 and wiring SL_i+1 is no longer supplied. , a selection signal is supplied to the wiring GL_i+2 and the wiring SL_i+2. As a result, i+1 The transistors 21 and 23 of the pixels 20 in the first row are turned off. In the pixel 20 in the (i+1)th row, a current corresponding to the video signal flows through the light emitting element. 20_(i+1,j), pixel 20_(i+1,j+1), pixel 20_(i+1,j+2) The display period starts at this point. The supply of the selection signal to the wiring SL_i+1 and the supply of the selection signal to the wiring SL_i+2 are performed in different periods as shown in Figures 8 and 9. That's fine.

[0125] Here, in the pixel 20_(i,j), a read signal is input to the gate of the transistor 22. Since the voltage Vcc is held at the same level as the voltage Vcc, the transistor 22 is maintained in the on state. Since a selection signal is supplied to i, the transistor 23 is maintained in an on state. Therefore, during the period when the pixel 20 in the (i+2)th row is selected or during the period when the pixel 20 in the (i+1)th row is in display operation, Even during the operation, the current characteristics of the transistor 22 of the pixel 20_(i,j) The information can be read out by the read circuit 16_i.

[0126] Next, as shown in FIG. 12, the selection of pixel 20 in the (i+2)th row is completed, and the selection of pixel 20 in the next row is continued. 20 selections are made. When the next row of pixels is selected, the next row is selected in the same way. On the other hand, the line GL_i+2 and the line SL_i As a result, the selection signal input to the pixel 20 in the i+2th row is no longer supplied. The transistors 21 and 23 are turned off. In pixel 20, a current corresponding to the video signal flows through the light emitting element. j), pixel 20_(i+2,j+1), pixel 20_(i+2,j+2), The interval will begin.

[0127] Thereafter, the next row is scanned and the same operation is repeated.

[0128] By the above operation, the video signal is written to the pixel and the current characteristics of the driving transistor are After the pixels 20 in the last row are selected, one frame of information can be read out. The frame period ends and the next frame period begins.

[0129] In the next frame period, all the pixels 20 in the i-th row are displayed in black, and the pixel in the i-th row and the j-th column To continue reading the current characteristic information from 20_(i,j), operate in the same way as in Figure 9. However, all the pixels 20 in the i-th row are displayed in black, and the pixel 20_(i,j) in the i-th row and j-th column For example, the current characteristic information is read from pixel 20_(i,j+1) in row i, column j+1. If this is the case, the operation should be as shown in FIG. 13 instead of FIG. 9. The wiring DL_j and the wiring DL_j+2 are connected to the pixel 20_(i,j) and the pixel 20_(i , j+2) video signal (here, a video signal for black display) is given, and the wiring DL_j+1 and A read signal is given to the pixel 20_(i, j+1) in the i-th row. Information on the current characteristics can be read out from the pixels 20_(i, j+1) in one column. Even during the next frame period, information on the current characteristics can be read out from another pixel. By repeating this operation, information on the current characteristics is obtained from all the pixels in one row. You will be able to read out the data.

[0130] Alternatively, in the next frame period, if some of the pixels 20 in the i-th row are not displayed in black, Therefore, instead of the operation shown in FIG. 9, the operation shown in FIG. 14 should be performed.

[0131] In this way, the pixels 20_(i, j) etc. read out by the operations shown in FIGS. 8 to 14 According to the information on the current characteristics of the transistor 22, the variation in the current characteristics of the transistor 22 is calculated. A corrected video signal is created, and this is used for the pixel 20_(i,j ) can be input. As a result, the influence of transistor variations or degradation can be This can reduce the noise.

[0132] The information on the current characteristics from the pixel 20_(i, j) is read out by the operation shown in FIG. After that, the process can be repeated until pixel 20_(i,j) is selected again in the next frame period. can.

[0133] If there is another row other than the i-th row where all the pixels are displayed in black, the same operation as above will This allows the information on the current characteristics to be read out.

[0134] Also, readout may be performed for multiple rows in one frame period. For example, in FIG. In the same way as in the case of the i-th row in FIG. 10, the readout signal and the image As a result, a voltage is applied to one pixel in the i+1th row. Alternatively, similar to the case of the i-th row in FIG. 11, a readout signal and a video signal may be supplied to the (i+2)th row. Therefore, it is possible to read out the current characteristic information for one pixel among the pixels in the (i+2)th row. As a result, reading can be performed on multiple rows.

[0135] The driving method described above is used to drive the driving transistor of each pixel of the display device shown in this embodiment mode. In this driving method, the display driving of the display device can be corrected. In parallel with this operation, variations in the current characteristics of the driving transistors can be corrected.

[0136] This allows pre-shipment inspection to be carried out on products incorporating the display device according to this embodiment. When inspecting the display of a product, it is possible to correct variations in the luminance of the product's pixels. This allows for a reduction in the inspection period before product shipment, reducing product costs. It is possible to achieve this.

[0137] Furthermore, the above-described driving method of the display device is also effective in turning on the power and displaying an image even after the product has been shipped. This is done every time the display is displayed. Therefore, there is no variation in the luminance due to deterioration over time after product shipment. This allows for automatic correction of the product's wear, thereby extending its lifespan. It is possible.

[0138] The pixel structure of the display device described in this embodiment is not limited to the structure shown in FIG. For example, in the pixel 20_(i, j) shown in FIG. 4, A structure in which a switch 26 is provided may be used. In this case, the circuit diagram is shown in FIG. 15(A) and FIG. 5(B). FIG. 15(A) shows the case where a switch 26 is provided in FIG. 4, and FIG. 15 (B) shows a case where the switch 26 is provided in FIG. 6. When the switch 26 is in a non-conducting state, By keeping the light emitting element 24 in the non-emitting state, for example, in the read pixel, the light emitting element 24 can be more reliably made to emit light. The light can be kept on.

[0139] <Example of readout circuit configuration> Next, an example of a specific configuration of the readout circuit 16 will be described with reference to FIGS. 16(A) to 16(D). This will be explained using the circuit diagram shown in the figure.

[0140] The read circuit 16a shown in FIG. 16(A) includes an operational amplifier 30a, a capacitance element 32, and a switch. The operational amplifier 30a has a non-inverting input terminal to which a reference potential is input, and an inverting input terminal to which a reference potential is input. The input terminal is connected to the wiring IL_i, one terminal of the switch 31, and one electrode of the capacitance element 32. The output terminal is connected to the other terminal of the switch 31 and the other electrode of the capacitance element 32. The operational amplifier 30a has a configuration in which the potential of the non-inverting input terminal and the potential of the inverting input terminal are Therefore, the potential of the wiring IL_i is equal to the potential of the non-inverting input terminal. Therefore, the read circuit 16a can control the voltage of the wiring IL_i. Therefore, during the address period, Even if the potential of the wiring IL_i is not changed, the potential of the wiring IL_i may be controlled by the read circuit 16a.

[0141] With this configuration, the read circuit 16a calculates the integral value of the current of the wiring IL_i. can be read out.

[0142] The read circuit 16b shown in FIG. 16B includes an operational amplifier 30b and a resistance element 33. The operational amplifier 30b has a non-inverting input terminal to which a reference potential is input, and an inverting input terminal to which a IL_i is connected to one electrode of the resistor element 33, and the output terminal is connected to the other electrode of the resistor element 33. The operational amplifier 30b is connected to the potential of the non-inverting input terminal and the potential of the inverting input terminal. Therefore, the potential of the wiring IL_i is equal to the non-inverting input Therefore, the read circuit 16b can be controlled by the potential of the wiring I It can be said that it has the function of controlling the potential of L_i. During this period, the potential of the wiring IL_i may be controlled by the read circuit 16b. .

[0143] With this configuration, the read circuit 16b converts the current value of the wiring IL_i into a voltage It can be converted to a value and read out.

[0144] The read circuit 16c shown in FIG. 16C includes an operational amplifier 30c. The non-inverting input terminal of the operational amplifier 30c is connected to the wiring IL_i, and the inverting input terminal of the operational amplifier 30c is connected to the wiring IL_i. The operational amplifier 30c is connected to the output terminal. Therefore, the potential of the wiring IL_i is set to the inverted input. The potential of the input terminal, that is, the potential of the output terminal, can be output from the operational amplifier 30c. Note that the read circuit 16c does not have a function of controlling the potential of the wiring IL_i. Therefore, as shown in FIG. 5, the potential of the wiring IL_i may be controlled using another circuit. stomach.

[0145] As shown in FIG. 16(D), the inverting input terminal is connected to the output terminal of the operational amplifier 30c. It can be connected to another wiring Vref without using the VREF pin. As a result, it can be operated as a comparator circuit. The potential of the wiring Vref and the potential of the inverting input terminal are compared to determine which is larger. This circuit can be used to configure an AD conversion circuit. In this case, the analog potential can be changed by changing the potential of the wiring Vref. It is possible to convert the voltage into a digital potential by connecting multiple operational amplifiers in parallel. A rush type AD conversion circuit may also be used.

[0146] With this configuration, the read circuit 16c receives the data from the transistor connected to the wiring IL_i. The threshold voltage of the transistor 22 can be read.

[0147] <Readout circuit connection example> 8 to 14, the wiring IL is connected to different read circuits 16. However, a plurality of wirings IL may be connected to one read circuit 16. An example of the configuration of the pixel 20 and readout circuit 16 having such a configuration is shown in FIG.

[0148] In FIG. 17, the wiring IL_i, the wiring IL_i+1, and the wiring IL_i+2 are connected via switches. Specifically, the wiring IL_i is connected to the switch 4 1_i and the read circuit 16, and the wiring IL_i+1 is connected to the switch 41_i+1 The wiring IL_i+2 is connected to the read circuit 16 via the switch 41_i+2. Here, three wirings IL are connected to one read circuit 16. The number of wirings IL connected to one read circuit 16 is is not limited to this and can be any number equal to or greater than 2.

[0149] When reading out information on the current characteristics from the pixel 20 in the i-th row, the switch 41_i is turned on. Then, the switches 41_i+1 and 41_i+2 are turned off. IL_i and the readout circuit 16 are brought into a conductive state, and the pixel 20 connected to the wiring IL_i Similarly, the current characteristic information can be read from the pixel 20 in the (i+1)th row. When reading information, the switch 41_i+1 is turned on, the switch 41_i, the switch When 41_i+2 is turned off and current characteristic information is read from the pixel 20 in the i+2th row The switch 41_i+2 is in the ON state, and the switch 41_i and the switch 41_i+1 are in the OFF state. This can be considered a state.

[0150] By adopting such a structure, a read circuit 16 is provided for each wiring IL. Since the number of read circuits 16 can be reduced compared to the above, the occupied area of ​​the circuit section 13 can be reduced. can be reduced.

[0151] The switch 41 can be configured by, for example, a transistor. Either the source or the drain of the transistor is connected to the wiring IL. The other end of the transistor may be connected to the read circuit 16. As the material, a semiconductor that can be used for the above-mentioned transistors 21 to 23 is Here, as the transistor used for the switch 41, in particular, O It is preferable to use an S transistor. This allows the information on the current characteristics to be read out. It is possible to prevent the current of the wiring IL of the row not flowing into the read circuit 16, The characteristic information can be read more accurately.

[0152] In addition, in the row where the information on the current characteristics is read, the current in the wiring IL is read by the read circuit 16 Therefore, the transistor used as the switch 41 has a large resistance compared to transistor 21, transistor 22, or transistor 23. It is preferable that the transistor used as the switch 41 has a current supply capability. W (channel width) / L (channel length) of transistor 21, transistor 22, or is preferably larger than W / L of the transistor 23.

[0153] <Example of output control circuit configuration> In the driving method of the display device shown in FIG. 3, the first row is scanned in order to display all the rows in black. The row shown was selected and the information on the current characteristics was read out. It is preferable to provide an output control circuit for controlling the signal output from the circuit 11. An example of the configuration of the path will be described with reference to Figs. 18(A) and 18(B). ) shows the drive circuit 11, the output control circuit 14 and the pixel section 15 of the display device, and FIG. (B) shows an example of the configuration of the latch circuit 43 shown in FIG. 18(A).

[0154] The display device shown in FIG. 18(A) has an output control circuit 14 provided between a drive circuit 11 and a pixel section 15. The wiring SL_i connected to the drive circuit 11 is connected to the output control circuit 14. One branch is connected to the row direction via a latch circuit 43 and a switch 44. The other end of the line SL_i is extended in the row direction via a switch 45. The electrodes are joined together via a switch 44 and a switch 45 and are extended in the row direction toward the pixel section 15. It is being done.

[0155] As shown in FIG. 18B, the latch circuit 43 includes a switch 46, an inverter 47, an inverter The switch 46 has one terminal connected to the wiring SL_i The other terminal is connected to the input terminal of the inverter 47 and the output terminal of the inverter 48. The output terminal of the inverter 47 is connected to the input terminal of the inverter 48. The output terminal of the inverter 49 is connected to the input terminal of the switch 44. The switch 46 is connected to one of the terminals by a wiring SW extending in the column direction. To be controlled.

[0156] In normal display, the switch 44 is driven in a non-conducting state and the switch 45 is driven in a conducting state. A signal is output from the circuit 11. On the other hand, when selecting a row for reading out information on the current characteristics, In this case, the switch 44 is turned on and the switch 45 is turned off, and the signal is transmitted from the drive circuit 11. Output.

[0157] Furthermore, when selecting a row in black display, the switch 46 is turned on via the wiring SW. This allows the signal input to the wiring SL_i to be held in the latch circuit 43. Therefore, the (i+1)th row is selected, and the signal input from the driver circuit 11 to the wiring SL_i is Even if the power supply is interrupted, the signal held in the latch circuit 43 will be transmitted to the transistor via the wiring SL_i. The power supply 23 can be left in the ON state.

[0158] In the display device shown in FIG. 18, a signal is output from the wiring SL via an output control circuit 14. However, the display device described in this embodiment is not limited to this example. For example, in addition to the wiring SL, the wiring GL may also be configured to output via the output control circuit 14. .

[0159] Note that in the display device described in this embodiment, the wiring GL is connected to a latch circuit 43. Since the above driving method can be used without holding a signal in the latch circuit 43, It may also be configured not to use it.

[0160] The display device described in this embodiment does not necessarily need to use the output control circuit 14. For example, if a decoder or the like is used to selectively output the signal of the driving circuit 11 to a desired row, The configuration may be such that the output control circuit 14 is not used.

[0161] It should be noted that this embodiment describes an example of the basic principle. The configurations and methods shown in this embodiment may be combined as appropriate with the configurations and methods shown in other embodiments. can.

[0162] (Embodiment 2) <Modification of the semiconductor device> In this embodiment, a configuration and a driving method of a semiconductor device different from that of the first embodiment will be described. This will be explained with reference to FIGS. 19 and 20.

[0163] A pixel structure of a display device according to this embodiment is shown in FIG. The display device shown in FIG. 3 has a pixel section 1 having (m×n) pixels 70. 5. It has various peripheral circuits and wiring, and the symbols for the peripheral circuits and wiring are common. Use the following.

[0164] FIG. 19 shows the configuration of pixel 70_(i,j) in row i and column j. A transistor 71, a p-channel transistor 72, a transistor 73, a light emitting element 74, and These elements of the pixel 70_(i, j) are connected to the wiring GL _i, wiring SL_i, wiring DL_j, wiring CL_j, and wiring IL_i are connected to the It is being done.

[0165] The specific connection relationship of the pixel 70_(i,j) is as follows: The port is connected to the wiring GL_i, and either the source or the drain is connected to the wiring DL_j. The other of the source and drain is connected to the gate of transistor 72. One of the source or drain of transistor 72 is connected to one of the source or drain of transistor 73. and one of the electrodes of the light emitting element 74 (hereinafter also referred to as a pixel electrode), The other of the drains (also referred to as the source electrode of the transistor 72) is connected to the wiring CL_j. The gate of the transistor 73 is connected to the wiring SL_i, and the source or drain The other electrode of the light emitting element 74 (hereinafter referred to as the common electrode) is connected to the wiring IL_i. A predetermined potential (hereinafter also referred to as a common potential) is applied to the first and second electrodes.

[0166] The wiring IL_i is connected to a read circuit 16 included in the circuit unit 13.

[0167] One electrode of the capacitor 75 is connected to the other of the source and drain of the transistor 71. and the gate of transistor 72, and the other electrode is connected to the source or The capacitor element 75 is connected to the other end of the drain. This allows a large amount of charge to be held in the gate electrode of the transistor 72, thereby extending the retention period of video information. It can be made easier.

[0168] The capacitor 75 is not necessarily provided. For example, If the parasitic capacitance between the source and the drain of the transistor 72 and the other is large, The capacitive element 75 can be replaced by a parasitic capacitance.

[0169] The configurations of the transistors 71 and 73 are the same as those of the transistors 21 and 22. The description of the transistor 23 can be referred to. For details, the description of the light-emitting element 24 can be referred to.

[0170] The pixel structure shown in FIG. 19 has the following features: the transistor 72 is a p-channel type; The pixel structure differs from that shown in FIG. 4 in that the connection relationship of the capacitance element 75 is different. Regarding the driving method of the display device shown in FIG. 19, the switching potential of the transistor 72 is In consideration of the fact that the transistors are reversed with respect to the transistor 22, The operation method of the transistor 72 can be taken into consideration. Regarding the material, the description of the transistor 22 can be referred to.

[0171] FIG. 20 shows a pixel structure different from the pixel structure shown in FIG. 19. The pixel structure shown in FIG. The pixel structure shown in FIG. 19 differs from the pixel structure shown in FIG. 19 in that the lines CL are provided extending in the row direction. The other configurations are similar.

[0172] Here, by configuring the wiring CL so that the potential can be changed in an analog manner, The potential of the wiring CL can be adjusted in accordance with the change in the potential of the wiring GL and the wiring SL. For example, in FIG. 8, the potential of the wiring CL_j is set lower than the common potential or approximately the same as the common potential. By setting the potential of the wiring CL_j in this way, the light-emitting element 74 can be reverse biased or unbiased. In this case, the black display state of the pixels in the i-th row can be maintained. As shown in FIG. 1, even if a forward bias is applied to the light emitting element 74, the common line CL_j The potential difference can be suppressed to a very small potential difference. A very small potential difference is a few volts. It is preferably about 2 volts or less, for example, 2 volts or less, more preferably 1 volt or less.

[0173] The driving method described above is used to drive the driving transistor of each pixel of the display device shown in this embodiment mode. In this driving method, the display driving of the display device can be corrected. In parallel with this operation, variations in the current characteristics of the driving transistors can be corrected.

[0174] The pixel structure of the display device shown in this embodiment is not limited to the structure shown in FIGS. For example, in the pixel 70_(i, j) shown in FIGS. A switch 76 may be provided between 74 and transistor 72. 21 and 22. FIG. 21 shows the case where a switch 76 is provided in FIG. 19. 22 shows the case where a switch 76 is provided in the configuration shown in FIG. 20. In the pixel 20_(i, j) etc., the switch 76 is kept in a non-conducting state. This makes it possible to more reliably maintain the light emitting element 74 in a non-light emitting state.

[0175] This embodiment may be modified, added, revised, deleted, or added to any or all of the other embodiments. This corresponds to application, superordinate conception, or subordinate conception. The structures and methods shown can be combined as appropriate with structures and methods shown in other embodiments.

[0176] (Embodiment 3) <Pixel configuration example> An example of a pixel layout that can be used in the above embodiment is shown in FIG. In 23, wiring, conductive layers, semiconductor layers, etc., represented by the same hatch pattern are made of the same material. In addition, an example of the configuration of the pixel 20 is shown here. A similar configuration can be applied to pixel 70.

[0177] The pixel 20 shown in FIG. 23A includes a transistor 21, a transistor 22, and a transistor 23. 3, a capacitor element 25. Also, a conductive layer having a function as a pixel electrode of the light-emitting element 24. 406. The connection relationship of each element can be seen in the explanation of FIG. The circles in the figure represent contact holes.

[0178] The transistor 21 has a semiconductor layer 411, the transistor 22 has a semiconductor layer 412, The transistor 23 includes a semiconductor layer 413. The semiconductor layer 413 includes a conductive layer 401a and a The semiconductor layer 412 is connected to the conductive layer 403a and the conductive layer 401b. The semiconductor layer 413 is connected to the conductive layer 403b and the conductive layer 403c. It is being done.

[0179] The conductive layer 401a is connected to the wiring DL. The conductive layer 401b may be connected to the conductive layer 402. The conductive layer 403a The conductive layer 403a is connected to the wiring CL. The conductive layer 403b is preferably a conductive layer 406 having a function as one electrode of the light-emitting element 24. A part of the conductive layer 403b may be used as the conductive layer 406. The conductive layer 403c is connected to the wiring IL. The conductive layer 405 is connected to the conductive layer 404, and the conductive layer 404 is connected to the wiring SL. Note that a part of the conductive layer 404 may be used as the conductive layer 405, or A part of SL may be used as the conductive layer 404 and the conductive layer 405 .

[0180] The conductive layer 401a functions as either the source or the drain of the transistor 21. The conductive layer 401b functions as the other of the source and drain of the transistor 21. The conductive layer 402 serves as the gate of the transistor 22 and one electrode of the capacitor 25. The conductive layer 403a functions as one of the source and drain of the transistor 22. The conductive layer 403b functions as the other of the source and drain of the transistor 22. One of the source and drain of the transistor 23 and the other electrode of the capacitor 25 The conductive layer 403c has both the function of the source and the drain of the transistor 23. The conductive layer 405 functions as a gate of the transistor 23. Note that the semiconductor layer 411, the semiconductor layer 412, and the semiconductor layer 413 each contain an oxide semiconductor. A semiconductor layer can be used. Alternatively, amorphous, microcrystalline, polycrystalline, or single-crystalline silicon can be used. A semiconductor layer containing a semiconductor such as silicon or germanium can be used.

[0181] In FIG. 23A, the transistors 21 to 23 are bottom-gate transistors. The transistors 21 to 23 may be bottom gate or top gate types. good.

[0182] Here, the wiring IL can be provided at a position where it overlaps with other wiring or conductive layers. In 23(A), the wiring IL is formed in a layer different from the wiring GL or wiring SL, and the wiring GL Alternatively, the pixel 2 can be arranged so as to have an area overlapping with the wiring SL. It is possible to provide wiring IL used to read out information on current characteristics while suppressing an increase in the area of ​​0. The wiring IL can be formed by any one or more of the conductive layers 401 to 406 or the semiconductor layer It may be provided so as to have an area overlapping with one or more of 411 to 413.

[0183] In addition, FIG. 23A shows a configuration in which the wiring CL is provided extending in the column direction. However, as shown in FIG. 20, the wiring CL may be provided extending in the row direction. An example of the configuration of such a pixel 20 is shown in FIG.

[0184] In FIG. 23B, the wiring CL is set to extend in the row direction, similar to the wiring SL and wiring GL. The wiring CL is provided in the same layer as the wiring SL and wiring GL, and The conductive layer 403a is provided between the wiring SL and the wiring GL. The conductive layer 407 is connected to the wiring CL.

[0185] Although the example shown here is one in which the wiring SL, wiring CL, and wiring GL are provided in the same layer, The wiring CL may be provided in a layer different from the wiring SL and wiring GL. The CL can be placed at a position where it overlaps with the wiring SL or the wiring GL. A wiring SL may be provided between the wiring CL and the wiring GL, or the wiring CL and the wiring SL A wiring GL may be provided between them.

[0186] This embodiment may be modified, added, revised, deleted, or added to any or all of the other embodiments. This corresponds to application, superordinate conception, or subordinate conception. The structures and methods shown can be combined as appropriate with structures and methods shown in other embodiments.

[0187] (Fourth embodiment) <Configuration example of display device> An example of the configuration of the display device will be described. FIG. 24 shows the configuration of a display device 80 in block diagram form. In the block diagram, the components are classified by function and are separated into independent blocks. However, it is difficult to separate the components into functions, and An element may be involved in multiple functions.

[0188] The display device 80 shown in FIG. 24 includes a panel 85 having a plurality of pixels 20 in a pixel section 15, and a control a roller 86, a CPU 83, an image processing circuit 82, an image memory 87, a memory 88, The panel 85 also includes a driving circuit 11, a driving circuit 12, and a circuit The driving circuit 11, the driving circuit 12, the circuit section 13, the pixel section 15 and the pixel The element 20 can be understood from the description of the previous embodiment.

[0189] The CPU 83 receives instructions input from the outside or instructions stored in a memory provided within the CPU 83. It decodes the commands and controls the overall operation of the various circuits in the display device 80. By doing so, the device has the function of executing the command.

[0190] The correction circuit 81 corrects the drive voltages included in each of the display pixels by the method described in the first embodiment. Generates data to correct the current characteristics based on the information on the current characteristics of the driving transistor. The memory 88 has a function of storing data for correcting the current characteristics.

[0191] The image memory 87 has a function of storing image data 89 input to the display device 80 . 24 shows an example in which only one image memory 87 is provided in the display device 80. However, a plurality of image memories 87 may be provided in the display device 80. For example, red, blue, green The pixel unit 15 receives full-color image data 89 corresponding to the three hues. When an image is displayed, an image memory 87 corresponding to each image data 89 is provided. You can do it like this.

[0192] The image memory 87 may be, for example, a DRAM (Dynamic Random Access Memory). Memory), SRAM (Static Random Access Memory) Alternatively, the image memory 87 may be provided with a memory circuit such as a VRAM (Video Random Access Memory). o RAM) may also be used.

[0193] The image processing circuit 82 processes the image data 89 in the image memory 8 in accordance with an instruction from the CPU 83. 7 and reads image data 89 from image memory 87. The image processing circuit 82 has a function of generating a video signal from the CPU 83. According to the command from the It has the function of correcting the video signal.

[0194] When a video signal is input, the controller 86 converts the video signal to match the specifications of the panel 85. It has a function of supplying the signal to the panel 85 after signal processing.

[0195] The controller 86 controls various circuits used to drive the drive circuits 12 and 11. The driving signal has a function of supplying a driving signal to the panel 85. The driving signal includes a signal for controlling the operation of the driving circuit 12. Control start pulse signal SSP, clock signal SCK, latch signal LP, drive circuit 1 1, a start pulse signal GSP, a clock signal GCK, and the like.

[0196] The display device 80 has a function of providing data and instructions to a CPU 83 included in the display device 80. The input device may include a keyboard, a pointing device, or the like. A touch device, a touch panel, a sensor, etc. can be used.

[0197] <Transistor configuration example 1> 25 and 30 show examples of transistors included in a display device, each of which has a top gate structure. A transistor is shown.

[0198] 30 shows a transistor 100B provided in the driving circuit and a transistor 100C provided in the pixel section 15. 25 shows a top view of transistor 100A, and FIG. 26 shows a top view of transistor 100B and transistor 100C. 30A is a top view of the transistor 100B, and FIG. 25A is a top view of the transistor 100A. -X2 and a cross-sectional view taken along the dashed line X3-X4 in FIG. 30(B). B) is a cross-sectional view taken along the dashed line Y1-Y2 in FIG. 30(A), and is a cross-sectional view taken along the dashed line Y1-Y2 in FIG. 30(B). 25A is a cross-sectional view of the transistor 100A and the transistor 100B. 25(B) is a cross-sectional view of the transistor 100B in the channel length direction. 1 is a cross-sectional view of the transistor 100A and the transistor 100B in the channel width direction.

[0199] In the top view of the transistor, the transistor 100A and the transistor 100B are also shown in the following drawings. As with the transistor 100B, some of the components may be omitted in the drawings. , the dashed line X1-X2 direction and the dashed line X3-X4 direction are the channel length direction, and the dashed line Y1 The -Y2 direction and the dashed dotted line Y3-Y4 direction may be referred to as the channel width direction.

[0200] The transistor 100A shown in FIG. 25 is an oxide film on an insulating film 111 formed on a substrate 101. The oxide semiconductor film 112, the conductive film 114 and the conductive film 116 in contact with the oxide semiconductor film 112, and the insulating film The insulating film 117 is formed on the oxide semiconductor film 112. The insulating film 117 is formed on the oxide semiconductor film 112. An insulating film 120 is provided on the transistor 100A.

[0201] The transistor 100B shown in FIG. 25 is an oxide film on an insulating film 111 formed on a substrate 101. The oxide semiconductor film 103, the conductive film 104 and the conductive film 105 in contact with the oxide semiconductor film 103, and the insulating film The insulating film 106 is provided on the oxide semiconductor film 103. The insulating film 106 is provided on the conductive film 107. An insulating film 120 is provided on the transistor 100B.

[0202] The transistor 100B includes a conductive film 111 overlapping the oxide semiconductor film 103 with the insulating film 111 interposed therebetween. That is, the conductive film 102 functions as a gate electrode. The transistor 100B is a dual-gate transistor. It is similar to Star 100A and has the same effect.

[0203] By applying different potentials to the conductive film 102 and the conductive film 107, the transistor 1 Alternatively, as shown in FIG. 25(B), the threshold voltage of 00B can be controlled. By applying the same potential to the film 102 and the conductive film 107, the on-current increases and the initial characteristic variations decrease. Reduction of adhesion, suppression of degradation in GBT stress test, and on-state at different drain voltages It is possible to suppress fluctuations in the current rise voltage.

[0204] In the drive circuit section (for example, drive circuit 11, drive circuit 12, etc.) and pixel section 15 of the display device The transistors included in the drive circuit are dual gate That is, compared with the pixel section 15, a transistor with a high on-current is used in the driving circuit section. has.

[0205] Furthermore, the channel lengths of the transistors included in the driver circuit portion and the pixel portion 15 may be different.

[0206] Typically, the channel length of the transistor 100B included in the drive circuit section is set to less than 2.5 μm. Alternatively, the thickness can be set to 1.45 μm or more and 2.2 μm or less. The channel length of the transistor 100A is set to 2.5 μm or more, or 2.5 μm or more and 20 μm or less. It can be below.

[0207] The channel length of the transistor 100B included in the driving circuit section is set to less than 2.5 μm, preferably By setting the thickness to 1.45 μm or more and 2.2 μm or less, the transistor 1 included in the pixel portion 15 As a result, the on-current can be increased compared to 0.0A. A drive circuit can be fabricated.

[0208] In the oxide semiconductor film 112, the conductive film 114, the conductive film 116, and the conductive film 118 are not overlapped. The region where the oxide semiconductor film 103 does not contain an element that forms oxygen vacancies. In the region where the conductive film 104, the conductive film 105, and the conductive film 107 do not overlap, oxygen vacancies are formed. Hereinafter, the elements that form oxygen vacancies will be described as impurity elements. Representative examples of rare gas elements include hydrogen and rare gas elements. The impurity elements are sodium, neon, argon, krypton, and xenon. Ion, carbon, nitrogen, fluorine, aluminum, silicon, phosphorus, chlorine, etc. are added to the oxide semiconductor film 1 The oxide semiconductor film 12 and the oxide semiconductor film 103 may be included.

[0209] The insulating film 120 is a film containing hydrogen, and is typically a nitride insulating film. When the oxide semiconductor film 112 and the oxide semiconductor film 103 are in contact with each other, the oxide semiconductor film 112 and the oxide semiconductor film 103 are included in the insulating film 120. The hydrogen contained in the oxide semiconductor film 112 diffuses into the oxide semiconductor film 103. In the region where the oxide semiconductor film 112 and the oxide semiconductor film 103 are in contact with the insulating film 120, It contains a lot of elements.

[0210] When a rare gas element is added to an oxide semiconductor film as an impurity element, the gold in the oxide semiconductor film is The bond between the metal element and oxygen is broken, and oxygen vacancies are formed. The interaction between the electron vacancy and hydrogen increases the electrical conductivity of the oxide semiconductor film. When hydrogen enters the oxygen vacancies contained in the semiconductor film, carriers (electrons) are generated. As a result, the conductivity is high.

[0211] Here, a partial enlarged view of the oxide semiconductor film 112 is shown in FIG. The following description will be given with reference to a partially enlarged view of the oxide semiconductor film 112 included in the transistor 100A. As shown in FIG. 6, the oxide semiconductor film 112 is in contact with the conductive film 114 or the conductive film 116. 112a, a region 112b in contact with the insulating film 120, and a region 112d in contact with the insulating film 117. When the side surface of the conductive film 118 has a tapered shape, It may have an area 112c that overlaps with the pad portion.

[0212] The region 112a functions as a source region and a drain region. 116 is tungsten, titanium, aluminum, copper, molybdenum, chromium, or tantalum When formed using conductive materials that easily bond with oxygen, such as simple substances or alloys, it is called an oxide semiconductor. The oxygen contained in the conductive film is bonded to the conductive material contained in the conductive film 114 and the conductive film 116, and the oxygen In addition, oxygen vacancies are formed in the oxide semiconductor film. In addition, some of the constituent elements of the conductive material that forms the conductive film 116 may be mixed in. As a result, the region 112a in contact with the conductive film 114 or the conductive film 116 becomes more conductive, and the source region The source and drain regions function as a source and drain region.

[0213] The region 112b functions as a low resistance region. Both contain a rare gas element and hydrogen. In this case, the impurity element passes through the tapered portion of the conductive film 118 and is added to the region 112c. The region 112c has a lower concentration of rare gas elements, which are an example of impurity elements, compared to the region 112b. However, the region 112c contains an impurity element. The breakdown voltage can be increased.

[0214] In the case where the oxide semiconductor film 112 is formed by a sputtering method, the regions 112a to 112c are 2d each contain a rare gas element, and compared with the region 112a and the region 112d, the region The concentration of the rare gas element is higher in the oxide semiconductor film 112b and the region 112c. When 2 is formed by sputtering, a rare gas element is used as the sputtering gas. Therefore, the oxide semiconductor film 112 contains a rare gas element, and the regions 112b and 112c are In 112c, rare gas elements are intentionally added to form oxygen vacancies. This is the cause. In the region 112b and the region 112c, A rare gas element other than 2d may be added.

[0215] In addition, since the region 112b is in contact with the insulating film 120, it is The hydrogen concentration is higher in the region 112b. When hydrogen diffuses, the region 112c has a higher hydrogen concentration than the region 112a and the region 112d. However, the hydrogen concentration is higher in the region 112b than in the region 112c.

[0216] In the region 112b and the region 112c, secondary ion mass spectrometry (SIMS) was performed. The hydrogen concentration obtained by Daily Ion Mass Spectrometry is , 8×10 19 atoms / cm 3 or more, or 1 x 10 20 atoms / cm 3 Above, again is 5 x 10 20 atoms / cm 3 The above can be done. The hydrogen concentration obtained by secondary ion mass spectrometry in the region 112d is 5×10 19 atoms / cm 3 or less, or 1 x 10 19 atoms / cm 3 or less, or 5 x 10 18 atoms / cm 3 or less, or 1 x 10 18 atoms / cm 3 or less, or 5 x 10 17 atoms / cm 3 or less, or 1 x 10 16 atoms / cm 3 It can be as follows:

[0217] In addition, impurity elements include boron, carbon, nitrogen, fluorine, aluminum, silicon, and phosphorus. Alternatively, when chlorine is added to the oxide semiconductor film 112, the regions 112b and 112c Therefore, compared with the region 112a and the region 112d, only the region 112a has an impurity element. The concentration of the impurity element is higher in the region 112b and the region 112c. In 12c, the concentration of impurity elements obtained by secondary ion mass spectrometry is 1×10 1 8 atoms / cm 3 More than 1×10 22 atoms / cm 3 or less, or 1 x 10 19 at oms / cm 3 More than 1×10 21 atoms / cm 3 or less, or 5 x 10 19 atoms / cm 3 5x10 or more 20 atoms / cm 3 It can be as follows:

[0218] Compared with the region 112d, the regions 112b and 112c have a high hydrogen concentration and a low rare gas concentration. The amount of oxygen deficiency caused by the addition of silicon elements is large. This results in high conductivity and a low resistance region. Typically, the resistivity of the region 112b and the region 112c is 1×10 -3 Ω cm or more 1×10 4Less than Ωcm or 1×10 -3 Ωcm or more 1×10 -1 Less than Ωcm It is possible.

[0219] In the regions 112b and 112c, the amount of hydrogen is equal to or less than the amount of oxygen vacancies. If the thickness is small, hydrogen is easily captured by oxygen vacancies and is less likely to diffuse into the region 112d, which is the channel. As a result, a normally-off transistor can be manufactured.

[0220] The region 112d functions as a channel.

[0221] In addition, the oxide semiconductor film 11 is formed by using the conductive films 114, 116, and 118 as masks. After adding the impurity element to the conductive film 2, the area of ​​the top surface of the conductive film 118 may be reduced. This is because, in the process of forming the conductive film 118, the mask on the conductive film 118 is slimmed. This can be achieved by performing processing to form a mask with finer structures. Then, the conductive film 118 and the insulating film 117 are etched using the mask, thereby forming a thin film as shown in FIG. A conductive film 118a and an insulating film 117a shown in (B) can be formed. For example, an ashing process using oxygen radicals can be used as the process. do.

[0222] As a result, in the oxide semiconductor film 112, the region 112c and the region 112 serving as a channel An offset region 112e is formed between the first and second electrodes 112a and 112b. The length of the bit region 112e is set to be less than 0.1 μm, thereby reducing the on-current of the transistor. It is possible to reduce the

[0223] The insulating film 117 and the insulating film 106 function as gate insulating films.

[0224] The conductive film 114 and the conductive film 116, as well as the conductive film 104 and the conductive film 105, form a source electrode and It functions as a drain electrode.

[0225] The conductive film 118 and the conductive film 107 function as gate electrodes.

[0226] The transistor 100A and the transistor 100B described in this embodiment have a channel The region 112d functions as a source region and a drain region. Between them, there is a region 112b and / or a region 112c which function as a low resistance region. It is possible to reduce the resistance between the transistor and the source and drain regions. The transistor 100A and the transistor 100B have a large on-state current and a high field-effect mobility.

[0227] In the transistors 100A and 100B, the conductive film 118 and the conductive Since the film 114 and the conductive film 116 do not overlap, the conductive film 118 and the conductive film 114 and the conductive film 116 are not overlapped. It is possible to reduce the parasitic capacitance between the conductive film 107 and the conductive film 116. Since the conductive film 104 and the conductive film 105 do not overlap, the conductive film 107 and the conductive film 104 and the conductive film 105 do not overlap. As a result, the parasitic capacitance between the substrate 101 and the conductive film 105 can be reduced. When a large-area substrate is used, the conductive film 114, the conductive film 116, the conductive film 118, and the conductive film It is possible to reduce the signal delay in the conductive films 104, 105, and 107. .

[0228] In the transistor 100A, the conductive films 114, 116, and 118 are A rare gas element is added to the oxide semiconductor film 112 as a mask, and the oxide semiconductor film 112 has oxygen vacancies. In the transistor 100B, the conductive film 104 and the conductive film 105 are formed. The conductive film 107 is used as a mask to add an impurity element to the oxide semiconductor film 103. Furthermore, the region having oxygen vacancies is formed by the insulating layer containing hydrogen. Since the insulating film 120 is in contact with the insulating film 120, hydrogen contained in the insulating film 120 diffuses into the region having oxygen deficiency. In other words, a low resistance region is formed by self-alignment. It is possible.

[0229] The transistors 100A and 100B described in this embodiment are formed in the region 11 By adding rare gas elements to 2b, oxygen vacancies are formed and hydrogen is added. Therefore, it is possible to increase the conductivity in the region 112b and It is possible to reduce the variation in the conductivity of the region 112b for each transistor. By adding rare gas elements and hydrogen to the region 112b, the conductivity of the region 112b can be controlled. It is Noh.

[0230] The configuration shown in FIG. 25 will be described in detail below.

[0231] The substrate 101 can be made of various substrates and is not limited to a specific one. Examples of the substrate include a semiconductor substrate (for example, a single crystal substrate or a silicon substrate), an SOI substrate, Plate, glass substrate, quartz substrate, plastic substrate, metal substrate, stainless steel substrate, Substrate with stainless steel foil, tungsten substrate, tungsten foil substrates, flexible substrates, laminated films, paper containing fibrous materials, or base films Examples of glass substrates include barium borosilicate glass and aluminoborosilicate glass. Acid glass or soda lime glass, etc. Flexible substrates, laminated films, base materials Examples of films include the following: Polyethylene naphthalate (PET), Polyethersulfone (P ES) or, for example, synthetic resins such as acrylic. Examples include polypropylene, polyester, polyvinyl fluoride, and Examples include polyvinyl chloride, polyamide, polyimide, and aramid. , epoxy, inorganic vapor deposition film, paper, etc. In particular, semiconductor substrates, single crystal substrates, Alternatively, by manufacturing a transistor using an SOI substrate or the like, characteristics, size, or Manufacture small-sized transistors with little variation in shape, high current capacity, etc. When a circuit is constructed using such transistors, the power consumption of the circuit can be reduced. Alternatively, a high degree of circuit integration can be achieved.

[0232] In addition, a flexible substrate is used as the substrate 101, and a transistor is formed directly on the flexible substrate. Alternatively, a separation layer may be provided between the substrate 101 and the transistor. After a semiconductor device is partially or entirely completed on the substrate, it is separated from the substrate 101 and then mounted on another substrate. In this case, the transistor can be mounted on a substrate with poor heat resistance or a flexible substrate. The above-mentioned peeling layer may be formed of, for example, a tungsten film and a silicon oxide film. The laminated structure of inorganic film and polyimide film, and the structure in which organic resin film such as polyimide is formed on the substrate. Composition etc. can be used.

[0233] An example of a substrate on which a transistor is transferred is a substrate on which the above-mentioned transistor is formed. In addition to the available substrates, paper substrates, cellophane substrates, aramid film substrates, polyimide film substrates Rubber substrate, stone substrate, wood substrate, fabric substrate (natural fibers (silk, cotton, linen), synthetic fibers (nylon, Polyurethane, polyester) or recycled fiber (acetate, cupra, rayon, recycled These substrates include raw polyester, leather substrates, and rubber substrates. This allows for the formation of transistors with good characteristics and low power consumption. This allows for the manufacture of devices that are less likely to break, more heat resistant, lighter in weight, or thinner.

[0234] The insulating film 111 can be formed as a single layer or a stack of an oxide insulating film or a nitride insulating film. Note that in order to improve interface characteristics with the oxide semiconductor film 103 and the oxide semiconductor film 112, Therefore, the insulating film 111 is formed by bonding at least the oxide semiconductor film 103 and the oxide semiconductor film 112. The contact region is preferably formed of an oxide insulating film. By using an oxide insulating film that releases more oxygen, the amount of oxygen contained in the insulating film 111 can be reduced by heat treatment. The oxygen can be transferred to the oxide semiconductor film 103 and the oxide semiconductor film 112. do.

[0235] The thickness of the insulating film 111 is 50 nm or more, or 100 nm or more and 3000 nm or less, or 20 The thickness of the insulating film 111 can be set to 0 nm or more and 1000 nm or less. The amount of oxygen released from the insulating film 111 can be increased, and the insulating film 111 and the oxide semiconductor film 103 and the oxide semiconductor film 112, and the interface states at the interfaces with the oxide semiconductor film 10 3 and oxygen vacancies in the region 112d of the oxide semiconductor film 112 can be reduced. be.

[0236] The insulating film 111 may be, for example, silicon oxide, silicon oxynitride, silicon nitride oxide, or nitride. Silicon, aluminum oxide, hafnium oxide, gallium oxide, Ga-Zn oxide, etc. The insulating film may be formed as a single layer or a multilayer.

[0237] The oxide semiconductor film 112 and the oxide semiconductor film 103 are typically made of In—Ga oxide, I n-Zn oxide, In-M-Zn oxide (M is Mg, Al, Ti, Ga, Y, Zr, L The oxide semiconductor film 112 is formed of an oxide of a metal such as Cr, Ce, Nd, or Hf. The oxide semiconductor film 103 has a light-transmitting property.

[0238] When the oxide semiconductor film 112 and the oxide semiconductor film 103 are an In-M-Zn oxide, The atomic ratio of In and M, excluding Zn and O, is 100 atoms. When expressed as ic%, In is 25 atomic % or more, M is less than 75 atomic %, or I n is 34 atomic % or more, and M is less than 66 atomic %.

[0239] The oxide semiconductor film 112 and the oxide semiconductor film 103 have an energy gap of 2 eV or more. Alternatively, it is 2.5 eV or more, or 3 eV or more.

[0240] The oxide semiconductor film 112 and the oxide semiconductor film 103 each have a thickness of 3 nm to 200 nm. Alternatively, it may be 3 nm or more and 100 nm or less, or 3 nm or more and 50 nm or less.

[0241] The oxide semiconductor film 112 and the oxide semiconductor film 103 are made of In-M-Zn oxide (M is Mg, In the case of Al, Ti, Ga, Y, Zr, La, Ce, Nd, or Hf, In-M-Zn oxide The atomic ratio of the metal elements in the sputtering target used to form the oxide film is In≧ It is preferable that M and Zn satisfy the condition M. The metal elements of such a sputtering target The atomic ratios of In:M:Zn=1:1:1, In:M:Zn=1:1:1.2, I n:M:Zn=2:1:1.5, In:M:Zn=2:1:2.3, In:M:Zn=2 In:M:Zn=3:1:2, etc. are preferable. The atomic ratios of the oxide semiconductor film 112 and the oxide semiconductor film 103 are calculated by adding the sputtering This includes a ±40% variation in the atomic ratio of metal elements contained in the target.

[0242] In addition, in the oxide semiconductor films 112 and 103, a Group 14 element When silicon or carbon is contained, the oxide semiconductor film 112 and the oxide semiconductor film 103 As a result, oxygen vacancies increase and the oxide semiconductor film 112 and the oxide semiconductor film 113 become n-type. The semiconductor film 103, especially in the region 112d, has a high concentration of silicon and carbon (secondary in The concentration obtained by mass spectrometry was 2 × 10 18 atoms / cm 3 Below, or 2 x10 17 atoms / cm 3 As a result, the transistor It has electrical characteristics in which the threshold voltage is positive (also called normally-off characteristics).

[0243] In addition, in the oxide semiconductor film 112 and the oxide semiconductor film 103, particularly in the region 112d, The concentration of alkali metals or alkaline earth metals obtained by secondary ion mass spectrometry is , 1×10 18 atoms / cm 3 or less, or 2 x 10 16 atoms / cm 3 The following Alkali metals and alkaline earth metals can form capacitive coupling elements when bonded to oxide semiconductors. This may cause a rear to be generated, which may increase the off-state current of the transistor. Therefore, it is preferable to reduce the concentration of alkali metals or alkaline earth metals in the region 112d. As a result, the transistor has electrical characteristics in which the threshold voltage is positive (normally off). Also called characteristics.

[0244] In addition, the oxide semiconductor film 112 and the oxide semiconductor film 103 are formed with nitrogen, particularly in the region 112d. When an element is included, electrons are generated as carriers, increasing the carrier density and making the material n-type. As a result, a transistor using an oxide semiconductor film containing nitrogen can be Therefore, the oxide semiconductor film, particularly the region 11 In 2d, it is preferable that nitrogen is reduced as much as possible. For example, the secondary ion species The nitrogen concentration obtained by quantitative analysis was 5 × 10 18 atoms / cm 3 The following can be done can.

[0245] In the oxide semiconductor film 112 and the oxide semiconductor film 103, particularly in the region 112d, By reducing the amount of impurity elements, the carrier density of the oxide semiconductor film can be reduced. Therefore, the oxide semiconductor film 112 and the oxide semiconductor film 103, particularly the region 112d In this case, the carrier density is 8×10 11 pieces / cm 3 Less than 1 x 10 11 pieces / cm 3 less than 1×10 10 pieces / cm 3 Less than 1 x 10 -9 pieces / cm 3 It can be more than that.

[0246] The oxide semiconductor films 112 and 103 have low impurity concentrations and low defect state densities. By using an oxide semiconductor film with low conductivity, a transistor with better electrical characteristics can be realized. Here, the impurity concentration is low and the defect level density is low (oxygen vacancy). High purity genuine or substantially high purity genuine is called high purity genuine or substantially high purity genuine. Since the oxide semiconductor is highly intrinsic, there are few carrier generation sources, and therefore it is possible to reduce the carrier density. Therefore, a channel region may be formed in the oxide semiconductor film. A transistor has an electrical characteristic in which the threshold voltage is positive (also known as a normally-off characteristic). In addition, a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film is prone to defects. Since the level density is low, the trap level density may also be low. A transistor using a qualitatively highly pure intrinsic oxide semiconductor film has an extremely small off-state current. When the voltage between the source electrode and the drain electrode (drain voltage) is in the range of 1V to 10V, The off-state current is below the measurement limit of the semiconductor parameter analyzer, i.e., 1×10 -13 Therefore, the oxide semiconductor film has a channel region of 0.25A or less. The transistors in which this is formed have small fluctuations in electrical characteristics and are highly reliable. This may be the case.

[0247] The oxide semiconductor film 112 and the oxide semiconductor film 103 may have a non-single-crystal structure, for example. The non-single crystal structure is, for example, a C-Axis Aligned Array (CAAC-OS) structure, which will be described later. Crystalline Oxide Semiconductor), polycrystalline structure, after Among non-single crystal structures, the amorphous structure is the most deficient. The defect density is high in CAAC-OS, and the defect density is lowest in CAAC-OS.

[0248] Note that the oxide semiconductor film 112 and the oxide semiconductor film 103 have an amorphous structure and a microcrystalline structure. The structure has two or more of the following regions: a region of a crystal structure, a region of a polycrystalline structure, a region of a CAAC-OS structure, and a region of a single crystal structure. The mixed film may be a film having a structure in which, for example, an amorphous structure region, a microcrystalline structure region, Two or more of the following regions: a polycrystalline structure region, a CAAC-OS region, and a single-crystalline structure region The mixed film may have a single layer structure having, for example, an amorphous structure region, a microcrystalline structure region, or the like. Two of the following structures are included: a region of a single crystal structure, a region of a polycrystalline structure, a region of a CAAC-OS structure, and a region of a single crystal structure. There are cases where the above structures are stacked.

[0249] Note that in the oxide semiconductor film 112 and the oxide semiconductor film 103, the region 112b and the region The crystallinity of the oxide semiconductor film 112 and the oxide semiconductor film 112d may be different. In the film 103, the crystallinity of the region 112c may differ from that of the region 112d. When an impurity element is added to the region 112b or the region 112c, This is because the region 112c is damaged, resulting in a decrease in crystallinity.

[0250] The insulating films 106 and 117 are formed as a single layer or a stack of an oxide insulating film or a nitride insulating film. Note that the interface characteristics between the oxide semiconductor film 112 and the oxide semiconductor film 103 can be In order to improve the thermal conductivity, the insulating films 106 and 117 are formed of at least an oxide semiconductor film. The region in contact with the oxide semiconductor film 112 and the oxide semiconductor film 103 is preferably formed using an oxide insulating film. The insulating film 106 and the insulating film 117 are preferably made of, for example, silicon oxide or silicon oxynitride. , silicon oxide nitride, silicon nitride, aluminum oxide, hafnium oxide, gallium oxide Alternatively, Ga—Zn oxide or the like may be used, and it may be provided as a single layer or a multilayer.

[0251] The insulating films 106 and 117 have a blocking effect against oxygen, hydrogen, water, and the like. By providing the insulating film, oxygen from the oxide semiconductor film 112 and the oxide semiconductor film 103 can be prevented. and hydrogen from the outside into the oxide semiconductor film 112 and the oxide semiconductor film 103. It can prevent the intrusion of water, etc. It is an insulating film that has a blocking effect on oxygen, hydrogen, water, etc. Examples include aluminum oxide, aluminum oxynitride, gallium oxide, gallium oxynitride, Examples include yttrium oxide, yttrium oxynitride, hafnium oxide, and hafnium oxynitride. do.

[0252] The insulating film 106 and the insulating film 117 are made of hafnium silicate (HfSiO x ), Nitrogen-doped hafnium silicate (HfSi x O y N z ), nitrogen-added huff HfAl x O y N z ), hafnium oxide, yttrium oxide, etc. The use of high-k materials can reduce gate leakage of transistors.

[0253] The insulating films 106 and 117 are formed using an oxide insulating film that releases oxygen by heating. By using the insulating film 106, oxygen contained in the insulating film 117 can be converted into oxide by heat treatment. The oxygen can be transferred to the semiconductor film 112 and the oxide semiconductor film 103.

[0254] Further, a silicon oxynitride film with few defects is used as the insulating film 106 and the insulating film 117. The silicon oxynitride film with few defects can be formed at a temperature of 100K or less after heat treatment. In the spectrum obtained by ESR measurement, the g value is 2.037 or more and 2.039 or less. The first signal, the second signal with a g value of 2.001 or more and 2.003 or less, and the g value of 1 A third signal between 0.964 and 1.966 is observed. Split width of the second signal and split width of the second and third signals The width is about 5 mT in the X-band ESR measurement. The g value is 2.037 or more. a first signal with a g value of 0.039 or less, a second signal with a g value of 2.001 or more and 2.003 or less, The sum of the spin densities of the third signals with g values ​​between 1.964 and 1.966 is 1 x10 18 spins / cm 3 less than 1 × 10 17 spins / cm 3 More than 1×10 18 spins / cm 3 is less than.

[0255] In addition, in the ESR spectrum below 100K, the g value is between 2.037 and 2.039. The first signal, the second signal with a g value between 2.001 and 2.003, and the g value between 1. The third signal, between 964 and 1.966, is nitrogen oxide (NOx , x is between 0 and 2 , or 1 or more and 2 or less). That is, a g value of 2.037 or more and 2.03 a first signal of 9 or less, a second signal of g-value 2.001 or more and 2.003 or less, and The lower the sum of the spin densities of the third signals with g values ​​between 1.964 and 1.966, the Therefore, it can be said that the content of nitrogen oxide contained in the silicon oxynitride film is small.

[0256] In addition, the silicon oxynitride film with few defects has a nitrogen concentration measured by secondary ion mass spectrometry. But 6×10 20 atoms / cm 3 The oxide film having few defects as the insulating film 117 is as follows. By using a silicon nitride film, nitrogen oxides are less likely to be generated, and the oxide semiconductor film 11 2, and carrier traps at the interface between the oxide semiconductor film 103 and the insulating film. In addition, it is possible to reduce the shift in threshold voltage of a transistor included in a display device. This makes it possible to reduce fluctuations in the electrical characteristics of the transistor.

[0257] The thickness of the insulating film 106 and the insulating film 117 is 5 nm or more and 400 nm or less, or 5 nm or more and 300 nm or less. It can be 100 nm or less, or 10 nm or more and 250 nm or less.

[0258] The conductive film 114, the conductive film 116, and the conductive film 118, as well as the conductive film 104, the conductive film 105, and the conductive film The conductive film 102 and the conductive film 107 may be made of aluminum, chromium, copper, tantalum, titanium, a metal element selected from the group consisting of molybdenum, nickel, iron, cobalt, and tungsten, or The metal element is formed by using an alloy containing the above metal elements or an alloy combining the above metal elements. In addition, the metal may be selected from one or more of manganese and zirconium. In addition, the conductive film 114, the conductive film 116, the conductive film 118, and the conductive The conductive film 104, the conductive film 105, the conductive film 102, and the conductive film 107 may have a single layer structure or a two or more layer structure. For example, a single layer structure of an aluminum film containing silicon, a manganese film, a single-layer structure of a copper film containing the titanium nitride film; a two-layer structure of a titanium film laminated on an aluminum film; Two-layer structure with a titanium film laminated on top, and two-layer structure with a tungsten film laminated on a titanium nitride film , a two-layer structure in which a tungsten film is laminated on a tantalum nitride film or a tungsten nitride film, Two-layer structure with copper film laminated on copper film containing gun, titanium film and aluminum film on the titanium film. A three-layer structure is formed by laminating a titanium film on top of that, and then forming a copper film on top of a manganese-containing copper film. There are three-layer structures in which a copper film containing manganese is formed on top of the laminated film. Aluminum, titanium, tantalum, tungsten, molybdenum, chromium, neodymium, scum An alloy film or a nitride film made of one or more elements selected from indium may also be used. good.

[0259] In addition, the conductive film 114, the conductive film 116, and the conductive film 118, as well as the conductive film 104 and the conductive film 10 5. The conductive film 102 and the conductive film 107 are made of indium tin oxide or indium oxide containing tungsten oxide. Indium oxide, indium zinc oxide with tungsten oxide, indium zinc oxide with titanium oxide Indium oxide, indium tin oxide with titanium oxide, indium zinc oxide, silicon oxide A light-transmitting conductive material such as indium tin oxide containing indium can also be used. Further, the conductive material having the light-transmitting property and the conductive material containing the metal element may be laminated. It is also possible to do so.

[0260] The conductive film 114, the conductive film 116, and the conductive film 118, as well as the conductive film 104, the conductive film 105, The thickness of the conductive film 102 and the conductive film 107 is 30 nm or more and 500 nm or less, or 100 nm or less. It can be set to 400 nm or more.

[0261] The insulating film 120 is a film containing hydrogen, and a representative example is a nitride insulating film. The insulating film can be formed using silicon nitride, aluminum nitride, or the like.

[0262] <Transistor configuration example 2> Next, another structure of a transistor included in a display device will be described with reference to FIG. Here, a transistor 100A is provided in the pixel section 15 as a modified example. 100C will be used for the description, but the transistor 100B in the driving circuit section will be used for the transistor 100C. The configuration of the insulating film 111 or the structures of the conductive film 114, the conductive film 116, and the conductive film 118 may be appropriately can be applied.

[0263] 27A to 27C are top views of a transistor 100C included in a display device. 27A is a top view of the transistor 100C, and FIG. 27(A) is a cross-sectional view taken along the dashed line Y3-Y4 in FIG. 27(A), and FIG. 27(C) is a cross-sectional view taken along the dashed line Y3-Y4 in FIG. FIG. 10 is a cross-sectional view taken along the dashed dotted line X3-X4.

[0264] The transistor 100C illustrated in FIG. 27 includes the conductive films 114, 116, and 118. The insulating film 111 has a two-layer or three-layer structure. The other components are the same as those of the transistor 1. It is the same as 00A and has the same effect.

[0265] First, the conductive films 114, 116, and 118 will be described.

[0266] The conductive film 114 is formed by laminating a conductive film 114a, a conductive film 114b, and a conductive film 114c in this order. The conductive film 114a and the conductive film 114c cover the surface of the conductive film 114b. That is, the conductive film 114a and the conductive film 114c function as a protective film for the conductive film 114b. do.

[0267] Like the conductive film 114, the conductive film 116 is made up of a conductive film 116a, a conductive film 116b, and a conductive film The conductive film 116a and the conductive film 116c are stacked in this order, and the conductive film 116a and the conductive film 116c are stacked in this order. That is, the conductive film 116a and the conductive film 116c cover the surface of the conductive film 116b. It functions as a protective film for b.

[0268] The conductive film 118 is formed by laminating a conductive film 118a and a conductive film 118b in this order.

[0269] The conductive films 114a, 116a, and 118a include the conductive film 114b, the conductive film 116b, a metal element contained in the conductive film 118b is prevented from diffusing into the oxide semiconductor film 112. The conductive films 114a, 116a, and 118a are formed using the following materials: Titanium, tantalum, molybdenum, tungsten, or titanium nitride, nitride, or alloys thereof The conductive film 114a can be formed using tantalum nitride, molybdenum nitride, or the like. The conductive film 116a and the conductive film 118a are made of a Cu-X alloy (X is Mn, Ni, Cr, Fe, It can be formed using Co, Mo, Ta, Ti, or the like.

[0270] The conductive films 114b, 116b, and 118b are formed using a low-resistance material. The conductive films 114b, 116b, and 118b are made of copper, aluminum, It can be formed using gold, silver, or other simple substances or alloys, or compounds containing these as the main components. can.

[0271] The conductive film 114c and the conductive film 116c are formed by the conductive film 114b and the conductive film 116b. By forming the conductive film 114b and the conductive film 116 using a film in which the metal element is passivated, The metal element contained in b migrates to the oxide semiconductor film 112 during the formation of the insulating film 128. The conductive film 114c and the conductive film 116c can be formed of a metal silicide. It can be formed using a material such as a metal silicon nitride, and a representative example is CuSi x ( x>0), CuSi x N y (x>0, y>0), etc.

[0272] Here, a method for forming the conductive film 114c and the conductive film 116c will be described. The conductive film 114b and the conductive film 116b are formed using copper. The film 116c is CuSi x N y It is formed using (x>0, y>0).

[0273] The conductive film 114b and the conductive film 116b are heated in a reducing atmosphere of hydrogen, ammonia, carbon monoxide, or the like. The oxides on the surfaces of the conductive films 114b and 116b are reduced by exposing them to plasma generated by the method described above. do.

[0274] Next, the conductive film 114b and the conductive film 116b are heated at a temperature of 200° C. or more and 400° C. or less. As a result, copper contained in the conductive film 114b and the conductive film 116b acts as a catalyst. The silane is decomposed into Si and H2, and the conductive film 114b and the conductive film 116b CuSi on the surface x (x>0) is formed.

[0275] Next, the conductive film 114b and the conductive film 116b are heated in an atmosphere containing nitrogen such as ammonia or nitrogen. By exposing the conductive film 114b and the conductive film 116b to the plasma generated by the above method, CuSi x (x>0) reacts with nitrogen contained in the plasma, and the conductive film 114c and the conductive As the film 116c, CuSi x N y (x>0, y>0) is formed.

[0276] In the above process, the conductive films 114b and 116b are treated with ammonia, nitrogen, or the like. After exposure to plasma generated in a nitrogen-containing atmosphere, the material is heated to a temperature between 200°C and 400°C. Meanwhile, the conductive films 114b and 116b are exposed to silane, so that the conductive films 114c and The conductive film 116c is made of CuSi x N y (x>0, y>0) may be formed.

[0277] Next, the insulating film 111 in which the nitride insulating film 111a and the oxide insulating film 111b are stacked will be described. I will explain.

[0278] For example, the nitride insulating film 111a may be made of silicon nitride, silicon nitride oxide, or aluminum nitride. The oxide insulating film 111 can be formed using aluminum nitride oxide, aluminum nitride oxide, or the like. b is formed using silicon oxide, silicon oxynitride, aluminum oxide, etc. By providing the nitride insulating film 111a on the substrate 101 side, hydrogen, water, etc. from the outside can be prevented. Therefore, it is possible to prevent diffusion of the oxide semiconductor film 112.

[0279] <Transistor configuration example 3> Next, another structure of a transistor included in a display device will be described with reference to FIGS. 28 and 29. Here, a transistor 100A provided in the pixel section 15 is described as a modified example. The following description will be given using the transistor 100D and the transistor 100E of the driving circuit section. The structure of the oxide semiconductor film 112 included in the transistor 100D or the structure of the oxide semiconductor film 112 included in the transistor 100B are the same as those of the transistor 100A. The structure of the oxide semiconductor film 112 included in the transistor 100E can be applied as appropriate.

[0280] 28A to 28C are top views of a transistor 100D included in a display device. 28A is a top view of the transistor 100D, and FIG. 28(A) is a cross-sectional view taken along the dashed line Y3-Y4 in FIG. 28(A), and FIG. 28(C) is a cross-sectional view taken along the dashed line Y3-Y4 in FIG. FIG. 10 is a cross-sectional view taken along the dashed dotted line X3-X4.

[0281] The transistor 100D shown in FIG. 28 has an oxide semiconductor film 112 with a multilayer structure. Specifically, the oxide semiconductor film 112 is formed between the oxide semiconductor film 113 and the insulating film 111. a, an oxide semiconductor film 113b in contact with the oxide semiconductor film 113a, and an oxide semiconductor film 11 3b, the oxide semiconductor in contact with the conductive film 114, the conductive film 116, the insulating film 117, and the insulating film 120; The other configurations are the same as those of the transistor 100A. It has an effect.

[0282] The oxide semiconductor films 113a, 113b, and 113c are typically Specifically, In-Ga oxide, In-Zn oxide, In-M-Zn oxide (M is Mg, A It is formed of metal oxides such as Ti, Ga, Y, Zr, La, Ce, Nd, or Hf .

[0283] The oxide semiconductor film 113a and the oxide semiconductor film 113c are typically made of In—Ga Oxide, In-Zn oxide, In-Mg oxide, Zn-Mg oxide, In-M-Zn oxide (M is Mg, Al, Ti, Ga, Y, Zr, La, Ce, Nd, or Hf), The energy of the conduction band minimum is closer to the vacuum level than that of the oxide semiconductor film 113b. is the energy of the conduction band minimum of the oxide semiconductor film 113a and the oxide semiconductor film 113c, and The difference in energy between the conduction band minimum of the oxide semiconductor film 113b and the oxide semiconductor film 113c is 0.05 eV or more and 0.0 7 eV or more, 0.1 eV or more, or 0.2 eV or more and 2 eV or less, 1 eV or less, 0. The energy difference between the vacuum level and the bottom of the conduction band is 5 eV or less, or 0.4 eV or less. It is also called electron affinity.

[0284] The oxide semiconductor film 113b is an In-M-Zn oxide (M is Mg, Al, Ti, Ga, Y, In the case of the oxide semiconductor film 113b, the oxide semiconductor film 113b is formed by adding a metal oxide such as Zr, La, Ce, Nd, or Hf. In the target used, the atomic ratio of metal elements is In:M:Zn=x1:y1:z1. Then 、 x1 / y1 is 1 / 3 or more and 6 or less, and further 1 or more and 6 or less, and z1 / y1 is preferably 1 / 3 or more and 6 or less, and more preferably 1 or more and 6 or less. When the ratio is 1 to 6, a CAAC-OS film is formed as the oxide semiconductor film 113b. A typical example of the atomic ratio of the target metal elements is In:M:Zn=1. :1:1, In:M:Zn=1:1:1.2, In:M:Zn=2:1:1.5, In: M:Zn=2:1:2.3, In:M:Zn=2:1:3, In:M:Zn=3:1:2 etc.

[0285] The oxide semiconductor film 113a and the oxide semiconductor film 113c are made of In-M-Zn oxide (M is M g, Al, Ti, Ga, Y, Zr, La, Ce, Nd, or Hf), oxide semiconductor The film 113a and the oxide semiconductor film 113c are formed using a target containing gold. If the atomic ratio of group elements is In:M:Zn=x2:y2:z2, 、 x2 / y2 <x1 / y 1, and z2 / y2 is preferably 1 / 3 or more and 6 or less, and more preferably 1 or more and 6 or less. Note that when z2 / y2 is greater than or equal to 1 and less than or equal to 6, the oxide semiconductor film 113a and the oxide semiconductor film 113b can be easily formed. The CAAC-OS film is easily formed as the metal semiconductor film 113c. Typical examples of atomic ratios are In:M:Zn=1:3:2 and In:M:Zn=1:3 :4, In:M:Zn=1:3:6, In:M:Zn=1:3:8, In:M:Zn=1 :4:3, In:M:Zn=1:4:4, In:M:Zn=1:4:5, In:M:Zn =1:4:6, In:M:Zn=1:6:3, In:M:Zn=1:6:4, In:M: Zn=1:6:5, In:M:Zn=1:6:6, In:M:Zn=1:6:7, In: Examples include M:Zn=1:6:8 and In:M:Zn=1:6:9.

[0286] Note that the oxide semiconductor films 113a, 113b, and 113c The atomic ratios each include a variation of ±40% of the above atomic ratios as an error.

[0287] The atomic ratio is not limited to these, and an appropriate atomic ratio may be selected depending on the required semiconductor characteristics. Just use the following.

[0288] The oxide semiconductor film 113a and the oxide semiconductor film 113c may have the same composition. The oxide semiconductor films 113a and 113c are made of In:Ga:Zn=1:3 :2, 1:3:4, 1:4:5, 1:4:6, 1:4:7, or 1:4:8 atomic ratio In-Ga-Zn oxide may also be used.

[0289] Alternatively, the oxide semiconductor film 113a and the oxide semiconductor film 113c may have different compositions. For example, the oxide semiconductor film 113a may be an In-Ga-Zn oxide film having an atomic ratio of In:Ga:Zn=1:3:2. The oxide semiconductor film 113c is made of Ga-Zn oxide and has a thickness of In:Ga:Zn=1:3:4. Alternatively, an In-Ga-Zn oxide having an atomic ratio of 1:4:5 may be used.

[0290] The oxide semiconductor film 113a and the oxide semiconductor film 113c have a thickness of 3 nm to 100 nm. The thickness of the oxide semiconductor film 113b is 3 nm or more, or 3 nm or more and 50 nm or less. The thickness is 200 nm or less, or 3 nm or more and 100 nm or less, or 3 nm or more and 50 nm or less. The oxide semiconductor film 113a and the oxide semiconductor film 113c are the oxide semiconductor film 1 By making the thickness thinner than 13b, the amount of fluctuation in the threshold voltage of the transistor is reduced. is possible.

[0291] The oxide semiconductor film 113a, the oxide semiconductor film 113b, and the oxide semiconductor film 113c The interface is STEM (Scanning Transmission Electron Microscope) Microscopy may be used to observe the lesion.

[0292] The oxide semiconductor film 113a and the oxide semiconductor film 113b are less likely to have oxygen vacancies than the oxide semiconductor film 113b. The oxide semiconductor film 113c is provided in contact with the upper surface and the lower surface of the oxide semiconductor film 113b. This can reduce oxygen vacancies in the oxide semiconductor film 113b. The oxide semiconductor film 113b is an oxide semiconductor film having one or more metal elements constituting the oxide semiconductor film 113b. The oxide semiconductor film 113 is in contact with the oxide semiconductor film 113a and the oxide semiconductor film 113c. a and the oxide semiconductor film 113b, and the interface between the oxide semiconductor film 113b and the oxide semiconductor film 113 The interface state density at the interface with the oxide semiconductor film 113c is extremely low. It is possible to reduce the oxygen vacancies contained in the silicon dioxide.

[0293] Furthermore, by providing the oxide semiconductor film 113a, the threshold voltage of the transistor and the like can be reduced. The variation in electrical characteristics can be reduced.

[0294] In addition, the oxide semiconductor film 113b contains one or more metal elements. Since the oxide semiconductor film 113b is provided in contact with the oxide semiconductor film 113b, the oxide semiconductor film 113b and the oxide At the interface with the semiconductor film 113c, carrier scattering is unlikely to occur, and the field effect of the transistor The mobility can be increased.

[0295] The oxide semiconductor films 113a and 113c are formed by the insulating film 111 and the insulating film 112. The constituent element of 117 is mixed into the oxide semiconductor film 113b, and an impurity level is formed. It also functions as a barrier film to prevent this.

[0296] From the above, it can be seen that the transistor described in this embodiment has improved electrical characteristics such as threshold voltage. This transistor has reduced variations in threshold voltage. By using the transistor having the same structure as that of the display device described in the above embodiment, Furthermore, the variation in threshold voltage can be effectively corrected.

[0297] FIG. 29 shows a transistor having a different structure from that shown in FIG.

[0298] 29A to 29C are top views of a transistor 100E included in a display device. 29A is a top view of the transistor 100E, and FIG. 29(A) is a cross-sectional view taken along the dashed line Y3-Y4 in FIG. 29(A), and FIG. 29(C) is a cross-sectional view taken along the dashed line Y3-Y4 in FIG. 29A is a cross-sectional view taken along the dashed line X3-X4. For clarity, in FIG. 29A, the substrate 1 01, insulating film 111, insulating film 117, insulating film 120, etc. are omitted. FIG. 29(B) is a cross-sectional view of the transistor 100E in the channel width direction. 10A and 10B are cross-sectional views of a transistor 100E in the channel length direction.

[0299] As in the transistor 100E illustrated in FIG. 29, the oxide semiconductor film 112 and the insulating film 111 are The oxide semiconductor film 113b in contact with the insulating film 117 and the oxide semiconductor film 113b in contact with the insulating film 117 are The semiconductor layer 113 may have a laminated structure of a compound semiconductor film 113c.

[0300] <Band structure> Here, the band structures of the transistors shown in FIGS. 34(A) is the band structure of the transistor 100D shown in FIG. 28, Therefore, the insulating film 111, the oxide semiconductor film 113a, the oxide semiconductor film 113b, and the oxide semiconductor film 113b are 34 shows the energy (Ec) of the bottom of the conduction band of the insulating film 113c and the insulating film 117. (B) is a band structure of the transistor 100E shown in FIG. 29, which is shown for ease of understanding. Therefore, the insulating film 111, the oxide semiconductor film 113b, the oxide semiconductor film 113c, and the insulating film 117 The energy (Ec) of the conduction band edge of

[0301] As shown in FIG. 34A, the oxide semiconductor film 113a, the oxide semiconductor film 113b, and the oxide semiconductor film 113c are In the oxide semiconductor film 113c, the energy of the conduction band minimum changes continuously. The oxide semiconductor film 113a, the oxide semiconductor film 113b, and the oxide semiconductor film 113c are formed. This can also be understood from the fact that oxygen easily diffuses between the two elements. The oxide semiconductor films 113a, 113b, and 113c have the following compositions: Although it is a laminate of films with different properties, it can also be said to be physically continuous.

[0302] The oxide semiconductor film, which is stacked with the same main component, is not simply stacked but is joined continuously. In this case, the energy of the conduction band edge changes continuously between layers. The interface between each layer is fabricated so that a U-Shape Well structure is formed. In oxide semiconductors, defect levels such as trap centers and recombination centers, or carrier The stacked structure is formed so that there are no impurities that hinder the flow of oxygen. When impurities are mixed between layers of a semiconductor film, the continuity of the energy band is lost, and the interface The carriers disappear due to trapping or recombination.

[0303] In FIG. 34A, the oxide semiconductor film 113a and the oxide semiconductor film 113c have the same Ec. Although the cases are shown as being similar, they may be different.

[0304] 34A, the oxide semiconductor film 113b serves as a well, and the transistor 10 In 0D, it can be seen that a channel is formed in the oxide semiconductor film 113b. The oxide semiconductor film 113a, the oxide semiconductor film 113b, and the oxide semiconductor film 113c are Since the energy at the edge changes continuously, a U-shaped well structure channel is used as a buried channel. It can also be called a ru.

[0305] 34B, the oxide semiconductor film 113b and the oxide semiconductor film 113c In the above, the energy of the conduction band minimum may change continuously.

[0306] As shown in FIG. 34B, the oxide semiconductor film 113b serves as a well, and the transistor 10 In FIG. 0E, it can be seen that a channel is formed in the oxide semiconductor film 113b.

[0307] The transistor 100D illustrated in FIG. 28 includes a metal element included in the oxide semiconductor film 113b. The oxide semiconductor films 113a and 113c each contain one or more of the following: , the interface between the oxide semiconductor film 113a and the oxide semiconductor film 113b, and the oxide semiconductor film 11 Therefore, an interface state is less likely to be formed at the interface between the oxide semiconductor film 3c and the oxide semiconductor film 113b. By providing the semiconductor film 113a and the oxide semiconductor film 113c, the threshold of the transistor This can reduce variations and fluctuations in electrical characteristics such as low voltage.

[0308] The transistor 100E illustrated in FIG. 29 includes an oxide semiconductor film 113b including only one metal element. Since the oxide semiconductor film 113c includes at least one of the above-mentioned elements, the oxide semiconductor film 113c and the Therefore, an interface state is less likely to be formed at the interface with the oxide semiconductor film 113b. By providing the film 113c, the variation in electrical characteristics such as the threshold voltage of the transistor can be reduced. In this way, the transistor with reduced variation in threshold voltage can be By using a resistor to configure the display device shown in the above embodiment, Therefore, the variation in threshold voltage can be effectively corrected.

[0309] <Transistor configuration example 4> Next, another structure of a transistor included in a display device will be described with reference to FIG.

[0310] 31A to 31C are top views of a transistor 100F included in a display device. 31A is a top view of the transistor 100F, and FIG. 31(A) is a cross-sectional view taken along the dashed line Y3-Y4 in FIG. 31(A), and FIG. 31(C) is a cross-sectional view taken along the dashed line Y3-Y4 in FIG. FIG. 10 is a cross-sectional view taken along the dashed dotted line X3-X4.

[0311] The transistor 100F shown in FIG. 31 is an oxide film on an insulating film 122 formed on a substrate 121. an oxide semiconductor film 123; an insulating film 124 in contact with the oxide semiconductor film 123; The conductive film 125 is in contact with the oxide semiconductor film 123 in a part of the opening 130a, and the insulating film 12 The conductive film 126 in contact with the oxide semiconductor film 123 in part of the opening 130b of FIG. The conductive film 127 overlaps with the oxide semiconductor film 123 with the film 124 interposed therebetween. An insulating film 128 and an insulating film 129 may be provided on the resistor 100F.

[0312] In the oxide semiconductor film 123, the conductive film 125, the conductive film 126, and the conductive film 127 overlap. In the following, the element that forms the oxygen vacancy is referred to as the oxygen vacancy. The explanation will be given as pure elements. Typical examples of impurity elements are hydrogen, boron, carbon, nitrogen, and fluorine. Examples of rare gas elements include fluorine, aluminum, silicon, phosphorus, chlorine, and rare gas elements. Examples include helium, neon, argon, krypton, and xenon.

[0313] When an impurity element is added to an oxide semiconductor film, a bond between a metal element and oxygen in the oxide semiconductor film is formed. Alternatively, an impurity element is added to the oxide semiconductor film, and oxygen vacancies are formed. When this happens, oxygen that has been bonded to a metal element in the oxide semiconductor film bonds to an impurity element, and the metal element is then released. As a result, oxygen is released from the oxide semiconductor film, and oxygen vacancies are formed. The rear density increases and the conductivity becomes higher.

[0314] Here, a partial enlarged view of the oxide semiconductor film 123 is shown in FIG. In this way, the oxide semiconductor film 123 has a region 123a in contact with the conductive film 125 and the conductive film 126. a region 123b in contact with the insulating film 128, a region 123c overlapping with the insulating film 124, and a region 123d and

[0315] The region 123a is highly conductive, similar to the region 112a shown in FIG. 26, and serves as a source region and It functions as a drain region.

[0316] The region 123b and the region 123c function as low resistance regions. The region 123b contains more impurity elements than the region 123c. In addition, when the side surface of the conductive film 127 has a tapered shape, one side of the region 123c The portion may overlap with the conductive film 127.

[0317] The impurity element is a rare gas element, and the oxide semiconductor film 123 is formed by a sputtering method. In this case, the regions 123a to 123d each contain a rare gas element, and the region 123a The concentration of rare gas elements in regions 123b and 123c is higher than that in regions 123d and 123e. This is because when the oxide semiconductor film 123 is formed by a sputtering method, the sputtering Since a rare gas element is used as a coupling gas, the oxide semiconductor film 123 contains a rare gas element. In addition, in order to form oxygen vacancies in the regions 123b and 123c, This is because rare gas elements are added to the region 123b and the region 123c. In the region 123b, a rare gas element different from that in the region 123a and the region 123d may be added.

[0318] The impurity element is boron, carbon, nitrogen, fluorine, aluminum, silicon, phosphorus, or salt. In the case of a silicon nitride film, only the regions 123b and 123c contain impurity elements. Compared with the regions 23a and 123d, the regions 123b and 123c have a higher concentration of impurity elements. In the regions 123b and 123c, the impurity concentration obtained by SIMS is The concentration of the pure element is 1×10 18 atoms / cm 3 More than 1×10 22 atoms / cm 3 or less, or 1 x 10 19 atoms / cm 3 More than 1×10 21 atoms / cm 3 below , or 5 x 10 19atoms / cm 3 5x10 or more 20 atoms / cm 3 The following It is possible.

[0319] When the impurity element is hydrogen, the regions 123b and 123d are larger than the regions 123a and 123d. The concentration of the impurity element is higher in the region 123b and the region 123c. The hydrogen concentration obtained by SIMS is 8×10 19 atoms / cm 3 That's all, or 1 x 10 20 atoms / cm 3 or more, or 5 x 10 20 atoms / cm 3 That's all It is possible.

[0320] Since the regions 123b and 123c contain impurity elements, oxygen vacancies increase, and the carrier As a result, the regions 123b and 123c become more conductive and have a lower resistance. By providing such a low resistance region, the channel and source regions The resistance between the drain and the drain regions can be reduced, and the transistor 100F Therefore, the transistor 100F has a large on-state current and a high field-effect mobility. For example, it can be suitably used for the driving transistor (transistor 22, etc.) shown in the previous embodiment. This can be done.

[0321] The impurity elements are hydrogen, boron, carbon, nitrogen, fluorine, aluminum, silicon, and lithium. In this case, the region 1 may contain one or more of fluorine, chlorine, or a rare gas element. 23b and region 123c, oxygen vacancies formed by rare gas elements, and hydrogen, boron, carbon, nitrogen, fluorine, aluminum, silicon, phosphorus, or Due to the interaction with one or more of the chlorines, regions 123b and 123c become more conductive. This may occur.

[0322] The region 123d functions as a channel.

[0323] In the insulating film 124, a region overlapping with the oxide semiconductor film 123 and the conductive film 127 is a gate electrode. The insulating film 124 functions as an insulating film. The region where the conductive film 25 and the conductive film 126 overlap functions as an interlayer insulating film.

[0324] The conductive films 125 and 126 function as a source electrode and a drain electrode. The conductive film 127 functions as a gate electrode.

[0325] In the manufacturing process of the transistor 100F described in this embodiment, the conductive film 127 functioning as a source electrode and a drain electrode, and the conductive film 125 and The conductive film 126 is formed at the same time. 27 does not overlap with the conductive film 125 and the conductive film 126, and the conductive film 127 does not overlap with the conductive film 125 and the conductive film 126. As a result, the parasitic capacitance between the substrate 121 and the conductive film 126 can be reduced. When a large-area substrate is used, the signals in the conductive films 125, 126, and 127 It is possible to reduce the signal delay.

[0326] In the transistor 100F, the conductive films 125, 126, and 127 are An impurity element is added to the oxide semiconductor film 123 as a mask. A low resistance region can be formed in the insulator.

[0327] As the substrate 121, the substrate 101 shown in FIG. 25 can be used appropriately.

[0328] As the insulating film 122, the insulating film 111 shown in FIG. 25 can be used as appropriate.

[0329] The oxide semiconductor film 123 is a film obtained by multiplying the oxide semiconductor film 103 and the oxide semiconductor film 112 shown in FIG. can be used appropriately.

[0330] The insulating film 124 can be formed by appropriately using the insulating film 106 and the insulating film 117 shown in FIG. .

[0331] The conductive films 125, 126, and 127 are formed at the same time, and therefore are made of the same material and It has the same laminated structure.

[0332] The conductive films 125, 126, and 127 are the same as the conductive films 114, 116, and 118 shown in FIG. 116 and the conductive film 118, as well as the conductive film 104, the conductive film 105, the conductive film 102 and the conductive film 107 can be used as appropriate.

[0333] The insulating film 128 can be formed as a single layer or a stack of an oxide insulating film or a nitride insulating film. Note that in order to improve the interface characteristics with the oxide semiconductor film 123, At least a region in contact with the oxide semiconductor film 123 is preferably formed using an oxide insulating film. In addition, by using an oxide insulating film that releases oxygen by heating as the insulating film 128, By the heat treatment, oxygen contained in the insulating film 128 can be transferred to the oxide semiconductor film 123. It is possible.

[0334] The insulating film 128 may be, for example, silicon oxide, silicon oxynitride, silicon nitride oxide, or nitride. Silicon, aluminum oxide, hafnium oxide, gallium oxide, Ga-Zn oxide, etc. The insulating film may be formed as a single layer or a multilayer.

[0335] The insulating film 129 is preferably a film that functions as a barrier film against hydrogen, water, and the like from the outside. The insulating film 129 may be made of, for example, silicon nitride, silicon nitride oxide, or aluminum oxide. Any of these may be used, and the layer may be provided as a single layer or a multilayer.

[0336] The thickness of the insulating film 128 and the insulating film 129 is 30 nm or more and 500 nm or less, or 1 The thickness can be 00 nm or more and 400 nm or less.

[0337] 25, the transistor 100F has an insulating film 1 A conductive film is provided under the oxide semiconductor film 22 so as to overlap with the oxide semiconductor film 123, thereby forming a dual gate structure. It can be made into.

[0338] <Transistor configuration example 5> Next, another structure of a transistor included in a display device will be described with reference to FIGS. 32 and 33. explain.

[0339] 32A to 32C are top views of a transistor 100G included in a display device. 32A is a top view of the transistor 100G, and FIG. 32(A) is a cross-sectional view taken along the dashed line Y3-Y4 in FIG. 32(A), and FIG. 32(C) is a cross-sectional view taken along the dashed line Y3-Y4 in FIG. FIG. 10 is a cross-sectional view taken along the dashed dotted line X3-X4.

[0340] The transistor 100G shown in FIG. 32 is an oxide film on an insulating film 132 formed on a substrate 131. an oxide semiconductor film 133; an insulating film 134 in contact with the oxide semiconductor film 133; The conductive film 137 overlaps with the oxide semiconductor film 133, and the insulating film 138 is in contact with the oxide semiconductor film 133. a film 139, an insulating film 138 formed on the insulating film 139, and a film formed by the insulating film 138 and the insulating film 13 The conductive film 135 in contact with the oxide semiconductor film 133 in the opening 140a of the insulating film 13 8 and the conductive film 13 in contact with the oxide semiconductor film 133 in the opening 140b of the insulating film 139. It has 6.

[0341] In the transistor 100G, the conductive film 137 functions as a gate electrode. The film 135 and the conductive film 136 function as a source electrode and a drain electrode.

[0342] In the oxide semiconductor film 133, the conductive film 135, the conductive film 136, and the conductive film 137 overlap. In the following, the element that forms the oxygen vacancy is referred to as the oxygen vacancy. The explanation will be given as pure elements. Typical examples of impurity elements are hydrogen, boron, carbon, nitrogen, and fluorine. Examples of rare gas elements include fluorine, aluminum, silicon, phosphorus, chlorine, and rare gas elements. Examples include helium, neon, argon, krypton, and xenon.

[0343] When an impurity element is added to an oxide semiconductor film, a bond between a metal element and oxygen in the oxide semiconductor film is formed. Alternatively, an impurity element is added to the oxide semiconductor film, and oxygen vacancies are formed. When this happens, oxygen that has been bonded to a metal element in the oxide semiconductor film bonds to an impurity element, and the metal element is then released. As a result, oxygen is released from the oxide semiconductor film, and oxygen vacancies are formed. The rear density increases and the conductivity becomes higher.

[0344] Here, a partial enlarged view of the oxide semiconductor film 133 is shown in FIG. In this way, the oxide semiconductor film 133 is in contact with the conductive film 135, the conductive film 136, or the insulating film 138. The conductive film 13 has a region 133b that is in contact with the insulating film 134 and a region 133d that is in contact with the insulating film 134. When the side surface of the conductive film 137 has a tapered shape, the conductive film 137 has a region 133c overlapping the tapered portion. You may do so.

[0345] The region 133b functions as a low resistance region. In addition, when the side surface of the conductive film 137 has a tapered shape, In this case, the impurity element passes through the tapered portion of the conductive film 137 and is added to the region 133c. The region 133c has a lower concentration of rare gas elements, which are an example of impurity elements, compared to the region 133b. However, the region 133c contains an impurity element. The breakdown voltage can be increased.

[0346] When the oxide semiconductor film 133 is formed by a sputtering method, the regions 133b to 133c are 3d each contain a rare gas element, and compared to region 133d, region 133b and region The oxide semiconductor film 133c has a higher concentration of rare gas elements. When formed by the sputtering method, rare gas elements are used as sputtering gas, so oxide semiconductors The film 133 contains a rare gas element, and the regions 133b and 133c This is because rare gas elements are intentionally added to form oxygen vacancies. In the region 133b and the region 133c, a different rare gas element is added than in the region 133d. It may be possible.

[0347] Furthermore, since the region 133b is in contact with the insulating film 138, the region 133b is smaller than the region 133d. b has a higher hydrogen concentration. Also, when hydrogen diffuses from region 133b to region 133c, The hydrogen concentration in the region 133c is higher than that in the region 133d. The region 133b has a higher hydrogen concentration.

[0348] In the region 133b and the region 133c, secondary ion mass spectrometry (SIMS) is performed. The hydrogen concentration obtained by Daily Ion Mass Spectrometry is , 8×10 19 atoms / cm 3 or more, or 1 x 10 20 atoms / cm 3 Above, again is 5 x 10 20 atoms / cm 3 In addition, the secondary The hydrogen concentration obtained by ion mass spectrometry is 5×10 19 atoms / cm 3 Below, again is 1 x 10 19 atoms / cm 3 or less, or 5 x 10 18 atoms / cm 3 Below, again is 1 x 10 18 atoms / cm 3 or less, or 5 x 10 17 atoms / cm 3 Below, again is 1 x 10 16 atoms / cm 3 It can be as follows:

[0349] In addition, impurity elements include boron, carbon, nitrogen, fluorine, aluminum, silicon, and phosphorus. Alternatively, when chlorine is added to the oxide semiconductor film 133, the regions 133b and 133c Therefore, compared with the region 133d, the region 133b and the region 133c have only the impurity element. The concentration of the impurity element is higher in the region 133b than in the region 133c. The concentration of impurity elements obtained by secondary ion mass spectrometry is 1×10 18 atoms / c m 3 More than 1×10 22 atoms / cm 3 or less, or 1 x 10 19 atoms / cm 3 Below top 1×10 21 atoms / cm 3 or less, or 5 x 10 19 atoms / cm 3 5x or more 10 20 atoms / cm 3 It can be as follows:

[0350] Compared with the region 133d, the regions 133b and 133c have a high hydrogen concentration and a low rare gas concentration. The amount of oxygen deficiency caused by the addition of silicon elements is large. This results in high conductivity and a low resistance region. Typically, the resistivity of the region 133b and the region 133c is 1×10 -3 Ω cm or more 1×10 4 Less than Ωcm or 1×10 -3 Ωcm or more 1×10 -1 Less than Ωcm It is possible.

[0351] In the regions 133b and 133c, the amount of hydrogen is equal to or less than the amount of oxygen vacancies. If the thickness is small, hydrogen is easily captured by oxygen vacancies and is less likely to diffuse into the region 133d that serves as a channel. As a result, a normally-off transistor can be manufactured.

[0352] The region 133d functions as a channel.

[0353] In addition, an impurity element is added to the oxide semiconductor film 133 using the conductive film 137 as a mask, and then the conductive film 137 is The area of ​​the top surface of each conductive film 137 may be reduced. In the forming process, a slimming process is performed on the mask on the conductive film 137 to make it finer. This can be done by forming a mask with a fine structure. By etching the conductive film 137 and the insulating film 134, the conductive film 13 shown in FIG. 7a and the insulating film 134a. The slimming process can be performed, for example, as follows: An ashing process using oxygen radicals or the like can be applied.

[0354] As a result, in the oxide semiconductor film 133, the region 133c and the region 133 An offset region 133e is formed between the first and second electrodes 133a and 133b. The length of the bit region 133e is set to be less than 0.1 μm, thereby reducing the on-current of the transistor. It is possible to reduce the

[0355] As the substrate 131 shown in FIG. 32, the substrate 101 shown in FIG. 25 can be used appropriately.

[0356] The insulating film 111 shown in FIG. 25 can be used as the insulating film 132 shown in FIG. do.

[0357] The oxide semiconductor film 133 shown in FIG. 32 is a composite of the oxide semiconductor film 103 shown in FIG. 25 and the oxide semiconductor film 104 shown in FIG. A conductive film 112 can be used as appropriate.

[0358] The insulating film 134 shown in FIG. 32 is formed by appropriately using the insulating film 106 and the insulating film 117 shown in FIG. It is possible.

[0359] The conductive film 135, the conductive film 136, and the conductive film 137 shown in FIG. 32 are the same as the conductive film 1 shown in FIG. 14, conductive film 116 and conductive film 118, and conductive film 104, conductive film 105, conductive film 10 2 and the conductive film 107 can be used as appropriate.

[0360] The thickness of the conductive film 137 and the insulating film 138 is 30 nm or more and 500 nm or less, or 1 The thickness can be 00 nm or more and 400 nm or less.

[0361] In the transistor 100G, the conductive film 137 does not overlap with the conductive film 135 and the conductive film 136. Therefore, the parasitic capacitance between the conductive film 137 and the conductive film 135 and between the conductive film 136 and the conductive film 137 can be reduced. As a result, when a large-area substrate is used as the substrate 131, the conductive film 135, the conductive film 136 and the conductive film 137, it is possible to reduce signal delay.

[0362] In addition, in the transistor 100G, the impurity element is oxidized using the conductive film 137 as a mask. In other words, a low resistance region is formed in a self-aligned manner. can be done.

[0363] 25, the transistor 100G has an insulating film 1 A conductive film is provided under the oxide semiconductor film 32 so as to overlap with the oxide semiconductor film 133, thereby forming a dual gate structure. It can be made into.

[0364] Crystal structure of oxide semiconductor film The structure of the oxide semiconductor film that forms the oxide semiconductor layer 520 will be described below. In this specification, when the crystal is trigonal or rhombohedral, it is referred to as a hexagonal system.

[0365] Oxide semiconductor films are roughly classified into non-single-crystal oxide semiconductor films and single-crystal oxide semiconductor films. The single-crystalline oxide semiconductor film includes a CAAC-OS film, a polycrystalline oxide semiconductor film, and a microcrystalline oxide semiconductor film. This refers to a conductive film, an amorphous oxide semiconductor film, etc.

[0366] [CAAC-OS membrane] The CAAC-OS film is one of oxide semiconductor films having a plurality of crystal parts aligned along the c-axis.

[0367] Transmission Electron Microscope (TEM) A bright-field image and a combined analysis image of the diffraction pattern of the CAAC-OS film were obtained by using a microscope. By observing the TEM image, multiple crystalline regions can be identified. On the other hand, high-resolution TEM images also reveal clear boundaries between crystalline parts, i.e., grain boundaries. Therefore, the CAAC-OS film is It can be said that the decrease in electron mobility caused by grain boundaries is unlikely to occur.

[0368] When a high-resolution TEM image of the cross section of the CAAC-OS film was observed from a direction approximately parallel to the sample surface, It can be seen that the metal atoms are arranged in layers in the crystalline part. Each layer of metal atoms is The CAAC-OS film is formed on a surface (also called a surface to be formed) or on a surface that reflects the unevenness of the surface. The CAAC-OS film has a shape and is aligned parallel to the surface on which the film is formed or the upper surface.

[0369] On the other hand, a high-resolution TEM image of the plane of the CAAC-OS film was observed from a direction approximately perpendicular to the sample surface. It was confirmed that the metal atoms in the crystals were arranged in a triangular or hexagonal shape. However, there is no regularity in the arrangement of metal atoms between different crystal parts.

[0370] X-ray diffraction (XRD) was performed on the CAAC-OS film. For example, a CAAC-OS film with InGaZnO4 crystals was found by structural analysis using the device. In the out-of-plane analysis, a peak was observed at a diffraction angle (2θ) of approximately 31°. This peak is attributed to the (009) plane of the InGaZnO4 crystal. Therefore, the crystals of the CAAC-OS film have a c-axis orientation, and the c-axis is approximately aligned on the surface on which the film is formed or on the upper surface. You can see that it is oriented vertically.

[0371] Out-of-plane growth of CAAC-OS films with InGaZnO4 crystals In the analysis, in addition to the peak at 2θ near 31°, a peak also appears at 2θ near 36°. The peak at 2θ around 36° is due to the presence of c-axis orientation in a part of the CAAC-OS film. The CAAC-OS film has a peak at 2θ around 31°. and preferably does not exhibit a peak at 2θ of around 36°.

[0372] The CAAC-OS film is an oxide semiconductor film with a low concentration of impurities. These are elements other than the main components of the oxide semiconductor film, such as silicon and transition metal elements. The elements that bond to oxygen more strongly than the metal elements that constitute the oxide semiconductor film, such as fluorine, are oxidized. By removing oxygen from the oxide semiconductor film, the atomic arrangement of the oxide semiconductor film is disrupted, reducing its crystallinity. In addition, heavy metals such as iron and nickel, argon, and carbon dioxide have an atomic radius (or molecular radius) is large, and when it is contained inside the oxide semiconductor film, The impurities contained in the oxide semiconductor film are likely to disturb the atomic arrangement and cause a decrease in crystallinity. Objects can act as carrier traps or carrier sources.

[0373] The CAAC-OS film is an oxide semiconductor film with a low density of defect states. Oxygen vacancies in the film can act as carrier traps or trap hydrogen, which can increase carrier It can be a source of odor.

[0374] Low impurity concentration and low defect level density (low oxygen vacancies) are called high purity intrinsic or The term "substantially highly purified intrinsic" refers to a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film. Since there are fewer carrier generation sources, the carrier density can be reduced. The transistor using the oxide semiconductor film has electrical characteristics ( It is also called normally-on.) It is rare for it to become a high-purity intrinsic or substantially high-purity The intrinsic oxide semiconductor film has few carrier traps. Transistors using this film have little fluctuation in electrical characteristics and are highly reliable. Note that it takes time for the charges trapped in the carrier traps in the oxide semiconductor film to be released. The impurity concentration is high and the charge is stable for a long time, so the charge may behave like a fixed charge. Therefore, a transistor using an oxide semiconductor film with a high density of defect states has unstable electrical characteristics. This may occur.

[0375] The electrical characteristics of the OS transistor using the CAAC-OS film are changed by irradiation with visible light or ultraviolet light. The fluctuation is small.

[0376] [Microcrystalline oxide semiconductor film] The microcrystalline oxide semiconductor film has a region where crystals can be confirmed in a high-resolution TEM image. The microcrystalline oxide semiconductor film has a crystal structure including a crystal region and a crystal region where no clear crystal part can be identified. The crystal part contained in the crystal has a size of 1 nm to 100 nm or 1 nm to 10 nm. In particular, the fine particles are often between 1 nm and 10 nm, or between 1 nm and 3 nm. The oxide semiconductor film having nanocrystals (nc) is called nc -OS(nanocrystalline oxide semiconductor) In addition, the nc-OS film has clearly defined grain boundaries in high-resolution TEM images. It may not be possible to recognize it.

[0377] The nc-OS film is a microscopic region (e.g., a region of 1 nm to 10 nm, especially a region of 1 nm or more). The nc-OS film has a periodic atomic arrangement in the region of 3 nm or less. There is no regularity in the crystal orientation between the crystal parts. Therefore, no orientation is observed throughout the film. Therefore, the nc-OS film cannot be distinguished from an amorphous oxide semiconductor film depending on the analysis method. For example, in the case of nc-OS films, X-rays with a diameter larger than that of the crystals are used. When structural analysis is performed using the D device, the crystal plane is In addition, the peaks indicating the probes larger than the crystalline part were not detected in the nc-OS film. Electron diffraction (also called selected area electron diffraction) using an electron beam with a diameter (for example, 50 nm or more) When the diffraction pattern is changed to 0.05μm, a halo-like diffraction pattern is observed. Nanobeam electrons are used, which use an electron beam with a probe diameter close to or smaller than the size of the crystal part. When diffraction is performed, spots are observed. If you do this, you may observe a circular (ring-shaped) area of ​​high brightness. When nanobeam electron diffraction was performed on the nc-OS film, multiple spots were observed within the ring-shaped region. It may be observed.

[0378] The nc-OS film is an oxide semiconductor film with higher order than an amorphous oxide semiconductor film. Therefore, the nc-OS film has a lower density of defect states than the amorphous oxide semiconductor film. In the nc-OS film, there is no regularity in the crystal orientation between different crystal parts. The S film has a higher defect state density than the CAAC-OS film.

[0379] [Amorphous oxide semiconductor film] The amorphous oxide semiconductor film has an irregular atomic arrangement in the film and is an oxide film that does not have a crystalline portion. An example is an oxide semiconductor film that has an amorphous state, such as quartz.

[0380] In the amorphous oxide semiconductor film, no crystalline portion can be confirmed in a high-resolution TEM image. When the structure of the amorphous oxide semiconductor film is analyzed using an XRD device, out-of-p In the analysis by the Lane method, no peaks indicating crystal planes were detected. When electron diffraction is performed on a conductive film, a halo pattern is observed. When nanobeam electron diffraction is performed on a conductive film, no spots are observed, and a halo pattern is observed. Observed.

[0381] The oxide semiconductor film has a structure that exhibits physical properties between the nc-OS film and the amorphous oxide semiconductor film. An oxide semiconductor film having such a structure is particularly called an amorphous-like oxide semiconductor. Body(a-like OS:amorphous-like Oxide Semicon The membrane is called a ductor.

[0382] In the a-like OS film, voids are observed in high-resolution TEM images. In addition, crystals can be clearly seen in high-resolution TEM images. The a-like OS film has a region where the crystal part is not observed and a region where the crystal part is not observed. Crystallization occurs due to the small amount of electron irradiation, which is the level observed with a TEM, and the growth of the crystals can be seen. On the other hand, if the nc-OS film is of good quality, the small amount of charge observed by TEM can be detected. Almost no crystallization due to electron irradiation is observed.

[0383] The size of the crystalline parts of the a-like OS film and the nc-OS film was measured using high-resolution TEM images. For example, InGaZnO4 crystal has a layered structure, and In- The unit cell of the InGaZnO4 crystal is I The structure consists of three nO layers and six Ga-Zn-O layers, with a total of nine layers stacked in the c-axis direction. Therefore, the distance between adjacent layers is determined by the lattice plane of the (009) plane. The value is approximately the same as the spacing (also called the d value), and is calculated to be 0.29 nm from crystal structure analysis. Therefore, we focused on the lattice fringes in high-resolution TEM images and found that the spacing between the lattice fringes was 0. In the area where the thickness is between 28 nm and 0.30 nm, each lattice fringe is InGaZn It corresponds to the ab plane of the O4 crystal.

[0384] The film density of an oxide semiconductor film may differ depending on the structure. When the composition of the oxide semiconductor film is known, the film density can be compared with that of a single-crystal oxide semiconductor film having the same composition. For example, the structure of the oxide semiconductor film can be estimated by The film density of the a-like OS film is 78.6% or more and less than 92.3% of the film density of the semiconductor film. For example, the film density of the nc-OS film is higher than that of the single-crystal oxide semiconductor film. The film density of the CAAC-OS film is 92.3% or more and less than 100%. The oxide semiconductor film having a film density of less than 78% of the film density of the oxide semiconductor film can be formed. This in itself is difficult.

[0385] The above will be explained using a specific example. For example, In:Ga:Zn=1:1:1 [atomic In the oxide semiconductor film that satisfies the numerical ratio, single crystal InGaZnO4 with a rhombohedral crystal structure The film density is 6.357g / cm 3 Therefore, for example, In:Ga:Zn=1:1: In oxide semiconductor films that satisfy the atomic ratio of 1, the film density of the a-like OS film is 5. 0g / cm 3 More than 5.9g / cm 3 For example, In:Ga:Zn=1: In oxide semiconductor films with an atomic ratio of 1:1, the film density and CA of the nc-OS film The film density of the AC-OS film is 5.9 g / cm 3 More than 6.3g / cm 3 It will be less than.

[0386] Note that there may be cases where single-crystal oxide semiconductor films having the same composition do not exist. By combining single-crystal oxide semiconductor films with different compositions, a single-crystal oxide semiconductor film with a desired composition can be obtained. The film density corresponding to the oxide semiconductor film can be calculated. The film density of the semiconductor film is determined by weighting the ratio of the combination of single-crystal oxide semiconductor films with different compositions. However, the film density should be calculated using as few types of single crystal oxides as possible. It is preferable to calculate the semiconductor film in combination.

[0387] The oxide semiconductor film may be, for example, an amorphous oxide semiconductor film, an a-like OS film, or a finely crystalline oxide semiconductor film. The film may be a stacked film including two or more of a crystalline oxide semiconductor film and a CAAC-OS film.

[0388] <Film formation method> The various films disclosed in this specification, such as metal films, semiconductor films, and inorganic insulating films, can be formed by sputtering or plating. It can be formed by plasma CVD, but other methods, such as thermal CVD (Chemical It may be formed by thermal CVD. For example, MOCVD (Metal Organic Chemical Vapor Deposition) deposition) method and ALD (Atomic Layer Deposition) You can use the law.

[0389] The thermal CVD method is a film formation method that does not use plasma, so defects are generated by plasma damage. This has the advantage that it will not be

[0390] In the thermal CVD method, the source gas and oxidant are simultaneously fed into the chamber, and the pressure inside the chamber is increased to atmospheric pressure. The film is formed by reacting the material near or on the substrate under reduced pressure and depositing it on the substrate. It is also possible.

[0391] In the ALD method, the chamber is kept at atmospheric pressure or reduced pressure, and the source gases for the reaction are sequentially introduced. Next, the gas is introduced into the chamber, and the film may be formed by repeating this gas introduction sequence. For example, by switching between two or more types of switching valves (also called high-speed valves), The source gases are supplied to the chamber in order, and the first source gas is supplied to the chamber in order to prevent the mixture of the source gases. Inert gas (argon, nitrogen, etc.) is introduced simultaneously with or after the fuel gas. In case of simultaneously introducing an inert gas, the inert gas is The second source gas may be introduced as a carrier gas, and an inert gas may be introduced at the same time as the second source gas is introduced. Also, instead of introducing an inert gas, the first raw material gas is discharged by vacuum evacuation. The first source gas may be adsorbed on the surface of the substrate to form a first layer. The second layer is deposited on the first layer by reacting with the second source gas introduced later. This process is repeated several times while controlling the gas introduction order until a desired thickness is achieved. By doing so, a thin film with excellent step coverage can be formed. The thickness of the thin film is determined by the order of gas introduction. The thickness can be precisely adjusted by changing the number of times the process is repeated. Suitable for making thin FETs (Field Effect Transistors). are.

[0392] The thermal CVD method such as the MOCVD method or the ALD method can be used in the above-described embodiments. It can form various films such as metal films, semiconductor films, and inorganic insulating films. For example, In-Ga When forming a Zn-O film, trimethylindium, trimethylgallium, and dimethylindium are used. Methyl zinc is used. The chemical formula for trimethyl indium is In(CH3)3. The chemical formula of trimethylgallium is Ga(CH3)3. Dimethylzinc The chemical formula is Zn(CH3)2. In addition, the combination is not limited to these, and trime Triethylgallium (chemical formula Ga(C2H5)3) can also be used instead of ethylgallium. Dimethyl zinc can also be replaced by diethyl zinc (chemical formula Zn(C2H5)2). can.

[0393] For example, when forming a hafnium oxide film using a film formation device that uses ALD, the solvent and Liquids containing hafnium precursor compounds (hafnium alkoxides, tetrakisdimethylamine, etc.) The raw material gas is vaporized hafnium amide (TDMAH) and oxidized Two types of gases are used: tetrakisdimethylamide hafnium (TDA) and ozone (O3). The chemical formula for nium is Hf[N(CH3)2]4. Other material liquids include tetrahydrofuran. Examples include kis(ethylmethylamido)hafnium.

[0394] For example, when forming an aluminum oxide film using a film forming apparatus that uses ALD, the solvent and a liquid containing an aluminum precursor compound (e.g., trimethylaluminum (TMA)) Two types of gases are used: a source gas containing methyltrimethylsilyl methyl ... The chemical formula for aluminum is Al(CH3)3. Other liquid materials include Tris(diisopropyl alcohol). Methylamido) aluminum, triisobutylaluminum, aluminum tris(2, 2,6,6-tetramethyl-3,5-heptanedionate).

[0395] For example, when forming a silicon oxide film using a film forming device that uses ALD, The chlorine contained in the adsorbed material is removed, and the oxidizing gas (O2 , nitrous oxide) radicals are supplied to react with the adsorbate.

[0396] For example, when forming a tungsten film using a film forming device that uses ALD, WF6 gas is used. The initial tungsten film is formed by repeatedly introducing WF6 and B2H6 gases. The tungsten film is formed using SiH gas instead of BH gas. Four gases may also be used.

[0397] For example, an oxide semiconductor film, such as In-Ga-Zn-O, can be formed using a film formation device that uses ALD. When forming a film, In(CH3)3 gas and O3 gas are introduced in sequence and repeatedly to form an In- Then, a GaO layer is formed using Ga(CH3)3 gas and O3 gas. Then, a ZnO layer is formed using Zn(CH3)2 gas and O3 gas. The order of layers is not limited to this example. In addition, by mixing these gases, In-Ga-O layers and In-Z layers can be formed. It is also possible to form a mixed compound layer such as an nO layer or a Ga-Zn-O layer. Alternatively, H2O gas obtained by bubbling with an inert gas such as Ar may be used. It is preferable to use O3 gas, which does not contain In(CH3)3 gas. 2H5)3 gas may be used. Also, instead of Ga(CH3)3 gas, Ga(C2H5 )3 gas may also be used.

[0398] <Off-state current> In this specification, unless otherwise specified, the off-state current refers to the current flowing when a transistor is in an off state (non-conducting state). The drain current when the device is in the on state (also called the on or off state). In the absence of a gate-source voltage Vgs, the n-channel transistor In a p-channel transistor, the voltage between the gate and source is lower than the threshold voltage Vth. This refers to the state in which the voltage Vgs is higher than the threshold voltage Vth. For example, in an n-channel transistor, The off-state current of a transistor is the voltage between the gate and source, Vgs, that is lower than the threshold voltage, Vth. It may refer to the drain current when

[0399] The off-state current of a transistor may depend on Vgs. The current is I or less if there is a value of Vgs at which the off-state current of the transistor is I or less. The off-state current of a transistor is the current that flows in the off state at a given Vgs. Off-state or sufficiently reduced off-current at Vgs within a given range It may refer to the off-state current in the off state at Vgs, etc.

[0400] As an example, when the threshold voltage Vth is 0.5V and Vgs is 0.5V, The current is 1×10 -9 A, and the drain current at Vgs of 0.1 V is 1×10 -13 A, and the drain current at Vgs = -0.5 V is 1 × 10 -19 A and Vgs The drain current at -0.8V is 1×10 -22 A n-channel transistor The drain current of the transistor is as follows when Vgs is -0.5V: Or, when Vgs is in the range of -0.5V to -0.8V, 1×10 -19 A or below Therefore, the off-state current of the transistor is 1×10 -19 It may be said that it is below A. The drain current of the transistor is 1×10 -22 Because there exists a Vgs below A , the off-state current of the transistor is 1×10 -22 It may be said that it is below A.

[0401] In this specification, the off-state current of a transistor having a channel width W is expressed as It may be expressed as the current value that flows. It may also be expressed as the current value that flows per a given channel width (for example, 1 μm). In the latter case, the unit of the off-state current is a unit with the dimension of current / length. It may be expressed as a unit (e.g., A / μm).

[0402] The off-state current of a transistor may depend on temperature. Unless otherwise specified, the off voltage is measured at room temperature, 60°C, 85°C, 95°C, or 125°C. Or, the reliability of the semiconductor device containing the transistor may be in doubt. or the temperature at which a semiconductor device including the transistor is used (for example, For example, it may refer to the off-state current at any temperature between 5°C and 35°C. The off-state current of the transistor is I or less, which means that the The temperature at which the reliability of the semiconductor device including the transistor is guaranteed, or the temperature at which the transistor The temperature at which the semiconductor device containing the stator is used (for example, any one of 5°C to 35°C) This indicates that there exists a value of Vgs at which the off-state current of the transistor is equal to or less than I at This may occur.

[0403] The off-state current of a transistor may depend on the voltage Vds between the drain and the source. In this specification, unless otherwise specified, the off-state current is measured when Vds is 0.1 V, 0.8 V, 1 V, 1.2V, 1.8V, 2.5V, 3V, 3.3V, 10V, 12V, 16V, or It may represent the off-state current at 20 V. Or, the semiconductor including the transistor Vds that guarantees the reliability of devices, etc., or semiconductor devices that include the transistor The off-state current of a transistor is sometimes expressed as the off-state current at Vds used in The current is less than or equal to I when Vds is 0.1V, 0.8V, 1V, 1.2V, 1.8V, 2 .5V, 3V, 3.3V, 10V, 12V, 16V, 20V, including transistors Vds that guarantees the reliability of the semiconductor device in which the transistor is included, or Vds used in devices, etc., Vg at which the off-state current of a transistor is I or less It may refer to the existence of a value of s.

[0404] In the above description of the off-state current, the drain may be read as the source. may also refer to the current that flows through the source when the transistor is in the off state.

[0405] In this specification, the term "leakage current" may be used to mean the same thing as "off current."

[0406] In this specification, the off-state current refers to the current that flows through a source when a transistor is in an off state. It can also refer to the current that flows between the source and drain.

[0407] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. It is possible.

[0408] (Embodiment 5) In this embodiment, an example of a cross-sectional view of a display pixel of a display device will be described. 1 shows a cross-sectional structure of a transistor 21, a capacitor 25, and a light-emitting element 24 included in a pixel 20. Illustrated.

[0409] Specifically, the display device shown in FIG. 35 has an insulating film 216 on a substrate 200, and The transistor 21 includes a semiconductor film 204 and a capacitor 25. , an insulating film 215 on the semiconductor film 204, and a film overlapping the semiconductor film 204 with the insulating film 215 sandwiched therebetween. The conductive film 203 functioning as a gate is in contact with the semiconductor film 204, and the insulating film 217 and The conductive film 205 provided in the opening of the insulating film 218 is also in contact with the semiconductor film 204 and is an insulating film. The conductive film 206 is provided in the opening of the insulating film 217 and the insulating film 218. The film 205 and the conductive film 206 function as the source and drain of the transistor 21. do.

[0410] The capacitor element 25 is made up of a semiconductor film 207 that functions as an electrode and an insulating film 21 on the semiconductor film 207. 5 overlaps with the semiconductor film 207 with the insulating film 215 sandwiched therebetween, and also functions as an electrode. The conductive film 210 is also included.

[0411] The insulating film 215 may be made of aluminum oxide, aluminum oxynitride, magnesium oxide, Silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, gallium oxide, germanium oxide, Yttrium oxide, zirconium oxide, lanthanum oxide, neodymium oxide, hafnium oxide and An insulating film containing one or more of tantalum oxide and tantalum oxide may be used as a single layer or a stacked layer. In this specification, an oxynitride is a compound having a higher oxygen content than nitrogen. Nitrogen oxide refers to a material whose composition contains more nitrogen than oxygen. .

[0412] When an oxide semiconductor is used for the semiconductor film 204, the insulating film 216 is formed by adding an oxide to the semiconductor film 204. It is desirable to use a material that can supply the element. By this, oxygen contained in the insulating film 216 can be transferred to the semiconductor film 204. This can reduce the amount of oxygen vacancies in the semiconductor film 204. The transfer of the ions to the semiconductor film 204 is achieved by performing a heat treatment after the semiconductor film 204 is formed. This can be done efficiently.

[0413] An insulating film 217 is provided on the semiconductor film 204, the conductive film 203, and the conductive film 210. An insulating film 218 is provided on the insulating film 217, and a conductive film 205 and a conductive film 206 are provided on the insulating film 218. 206, a conductive film 209, and an insulating film 219 are provided. The conductive film 201 is formed in the opening of the insulating film 219. The conductive film 212 is connected to the conductive film 205, and the conductive film 212 is connected to the conductive film 209 in the opening of the insulating film 219. and is connected.

[0414] When an oxide semiconductor is used for the semiconductor film 204, the insulating film 217 is resistant to oxygen, hydrogen, water, and alkali. It is preferable that the insulating layer has a blocking function for alkali metals, alkaline earth metals, etc. By providing the insulating film 217, oxygen can be diffused from the semiconductor film 204 to the outside, and oxygen can be diffused from the outside to the semiconductor film 204. The insulating film 217 can prevent hydrogen, water, etc. from entering the insulating film 204. For example, a nitride insulating film can be used. Examples of the nitride insulating film include silicon nitride, nitride Silicon oxide, aluminum nitride, aluminum nitride oxide, etc. Instead of a nitride insulating film that has a blocking effect against water, alkali metals, alkaline earth metals, etc. Alternatively, an oxide insulating film having a blocking effect against oxygen, hydrogen, water, and the like may be provided. Examples of oxide insulating films having a blocking effect against hydrogen, water, and the like include aluminum oxide and oxide. Aluminum oxide nitride, gallium oxide, gallium oxide nitride, yttrium oxide, yttrium oxide nitride Examples include tritium, hafnium oxide, and hafnium oxynitride.

[0415] On the insulating film 219, the conductive film 201, and the conductive film 212, an insulating film 220 and a conductive film 21 3 is provided, and the conductive film 213 is connected to the conductive film 212 in the opening of the insulating film 220. are.

[0416] An insulating film 225 is provided over the insulating film 220 and the conductive film 213. The insulating film 225 is The insulating film 225 has an opening at a position overlapping with the conductive film 213. An insulating film 226 is provided at a position different from the opening of the insulating film 225. An EL layer 227 and a conductive film 228 are stacked in this order on the insulating film 226. The conductive film 213 and the conductive film 228 overlap with each other with the EL layer 227 sandwiched therebetween. The conductive film 213 and the conductive film 228 function as a light-emitting element 24. the other acts as a cathode.

[0417] The display device also has a substrate 230 that faces the substrate 200 with the light emitting element 24 sandwiched therebetween. A light-shielding layer is provided under the substrate 230, that is, on the surface of the substrate 230 that is closer to the light-emitting element 24. The shielding film 231 has a function of shielding the light emitting element. The substrate 2 has an opening in the area where the light emitting element 24 overlaps. Underneath 30 is a colored layer 232 that transmits visible light in a specific wavelength range.

[0418] The insulating film 226 adjusts the distance between the light emitting element 24 and the substrate 230. In some cases, it may be omitted.

[0419] In this embodiment, a top panel is used to extract light from the light emitting element 24 from the side opposite to the element substrate. The bottom emission structure is shown, in which the light from the light emitting element 24 is extracted from the element substrate side. The light from the light emitting element 24 is incident from the element substrate side and from the opposite side of the element substrate. A dual emission structure that extracts both the heat and the air can also be one aspect.

[0420] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. It is possible.

[0421] (Embodiment 6) In this embodiment, a display device including a light-emitting element of one embodiment of the present invention and the display device An electronic device equipped with an input device will be described with reference to FIGS.

[0422] <Touch panel explanation 1> In the present embodiment, an example of an electronic device is a device that combines a display device and an input device. The touch panel 500 will be described. The use cases will be explained below.

[0423] 36(A) and (B) are perspective views of the touch panel 500. 5, for clarity, representative components of touch panel 500 are shown.

[0424] The touch panel 500 includes a display device 501 and a touch sensor 595 (see FIG. 36(B)). The touch panel 500 also includes a substrate 510, a substrate 570, and a substrate 590. It should be noted that the substrate 510, the substrate 570, and the substrate 590 are all flexible. Any one or all of the substrates 510, 570, and 590 may be rigid. A different configuration may also be used.

[0425] The display device 501 has a plurality of pixels on a substrate 510 and can supply signals to the pixels. The substrate 510 has a plurality of wirings 511. The plurality of wirings 511 are routed to the outer periphery of the substrate 510. , a part of which constitutes a terminal 519. The terminal 519 is connected to the FPC 509(1).

[0426] The substrate 590 includes a touch sensor 595 and a plurality of wirings 598 connected to the touch sensor 595. A plurality of wirings 598 are routed around the periphery of the substrate 590, some of which have terminals. The terminal is connected to the FPC 509(2). For clarity, the touch sensor provided on the back side of the substrate 590 (the surface facing the substrate 510) is The electrodes and wiring of the sensor 595 are shown by solid lines.

[0427] As the touch sensor 595, for example, a capacitance type touch sensor can be applied. The methods include a surface capacitance method and a projected capacitance method.

[0428] Projected capacitive touch panels are classified into self-capacitance and mutual-capacitance types, which differ mainly in their drive methods. The mutual capacitance method is preferable because it allows simultaneous multi-point detection.

[0429] The touch sensor 595 shown in FIG. 36(B) is a projected capacitive touch sensor. This is the applied configuration.

[0430] The touch sensor 595 can detect the proximity or contact of a detection object such as a finger. Various sensors can be applied.

[0431] The projected capacitive touch sensor 595 has an electrode 591 and an electrode 592. 591 is connected to one of a plurality of wirings 598, and the electrode 592 is connected to another of the plurality of wirings 598. Connect to either one.

[0432] As shown in Figures 36(A) and 36(B), the electrodes 592 are made up of a plurality of four electrodes repeatedly arranged in one direction. It has a shape in which sides are connected at corners.

[0433] The electrode 591 is quadrilateral and is repeatedly arranged in a direction intersecting the direction in which the electrode 592 extends. It is being done.

[0434] The wiring 594 is connected to two electrodes 591 that sandwich the electrode 592. It is preferable that the area of ​​the intersection of the wiring 594 is as small as possible. The area of ​​the region where the film is not provided can be reduced, and the variation in transmittance can be reduced. This can reduce variations in the brightness of the light passing through the touch sensor 595.

[0435] The shapes of the electrodes 591 and 592 are not limited to this, and may take various shapes. For example, a plurality of electrodes 591 are arranged with as few gaps as possible, and the electrodes are connected via an insulating layer. Alternatively, a plurality of electrodes 592 may be provided at intervals so that there is an area where the electrodes 592 do not overlap with the electrodes 591. At this time, a dummy electrode electrically insulated from the two adjacent electrodes 592 is provided between them. Providing a negative electrode is preferable because it allows the area of ​​the region with different transmittance to be reduced.

[0436] <Explanation about the display device> Next, the display device 501 will be described in detail with reference to FIG. , which corresponds to a cross-sectional view taken along the dashed dotted line X1-X2 shown in FIG. 36(B).

[0437] The display device 501 has a plurality of pixels arranged in a matrix. and a pixel circuit for driving the display element.

[0438] In the following description, a light emitting element that emits white light is applied to a display element. However, the display element is not limited to this. For example, the color of light emitted by each adjacent pixel Light-emitting elements with different emission colors may be applied so that the light-emitting elements have different emission colors.

[0439] In this specification and the like, the term "display element," "display device having a display element," "light emitting element," "light emitting device," "light emitting element ... A light-emitting device, which is a device having a light-emitting element and a light-emitting element, can be formed in various forms or in various forms. The display element, the display device, the light-emitting element or the light-emitting device can have, for example, E EL (electroluminescence) elements (EL elements containing organic and inorganic materials, organic EL elements) , inorganic EL elements), LEDs (white LEDs, red LEDs, green LEDs, blue LEDs, etc.), Transistors (transistors that emit light according to the current), electron-emitting devices, liquid crystal devices, electronic ink, electrophoretic element, grating light valve (GLV), plasma display ( PDP), display elements using MEMS (microelectromechanical systems) , Digital Micromirror Device (DMD), DMS (Digital Micro Shutter MIRASOL (registered trademark), IMOD (Interference Modulation shutter-type MEMS display elements, optical interference-type MEMS display elements, Trowetting element, piezoelectric ceramic display, or carbon nanotube In addition to these, the display element, the display element, A display device, a light-emitting element, or a light-emitting device is a device that uses electrical or magnetic effects to improve contrast, brightness, etc. In some cases, the display medium has a variable reflectance, transmittance, etc. An example of a display device using electron-emitting devices is an EL display. As for the display, a field emission display (FED) or an SED type flat panel display is used. Play (SED: Surface-conduction Electron-emit An example of a display device using a liquid crystal element is a liquid crystal display. Displays (transmissive LCD displays, semi-transmissive LCD displays, reflective LCD displays) LCD, direct-view LCD, projection LCD, etc. An example of a display device using electronic liquid powder (registered trademark) or an electrophoretic element is an electronic page. There are also other LCDs that can be used to realize semi-transmissive and reflective LCD displays. In this case, part or all of the pixel electrode can function as a reflective electrode. For example, a part or the whole of the pixel electrode may be made of aluminum, silver, etc. Furthermore, in this case, a memory circuit such as an SRAM should be provided under the reflective electrode. This allows for further reduction in power consumption. When using D, graphene or graphite is placed under the LED electrodes or nitride semiconductor. Graphene or graphite may be formed into a multilayer film by stacking multiple layers. By providing graphene or graphite as shown above, it is possible to form a nitride semiconductor, e.g. For example, it is possible to easily form an n-type GaN semiconductor layer having a crystal. An LED can be constructed by providing a p-type GaN semiconductor layer with crystals on top of the In addition, Al is interposed between the graphene or graphite and the n-type GaN semiconductor layer with crystals. An N layer may be provided. The GaN semiconductor layer of the LED may be formed by MOCVD. However, by providing graphene, the GaN semiconductor layer of the LED becomes It is also possible to form the film by the evaporative deposition method.

[0440] The substrate 510 and the substrate 570 are made of, for example, a material having a water vapor permeability of 10 -5 g / (m 2 ·d ay) or less, preferably 10 -6 g / (m 2 A material with flexibility of less than 10 ... Alternatively, the thermal expansion coefficient of the substrate 510 and the thermal expansion coefficient of the substrate 570 may be For example, it is preferable to use a material with a linear expansion coefficient of 1×10 -3 / K or less , preferably 5 x 10 -5 / K or less, more preferably 1×10 -5 / K or less It can be suitably used.

[0441] The substrate 510 includes an insulating layer 510a that prevents impurities from diffusing into the light-emitting element, and a flexible substrate 510b. 10b, and an adhesive layer 510c that bonds the insulating layer 510a and the flexible substrate 510b together. The substrate 570 is a laminated body having an insulating layer 57 that prevents impurities from diffusing into the light-emitting element. The insulating layer 570a is bonded to the flexible substrate 570b. and adhesive layer 570c.

[0442] The adhesive layer 510c and the adhesive layer 570c may be made of, for example, polyester, polyolefin, Polyamide (nylon, aramid, etc.), polyimide, polycarbonate, polyurethane, Acrylic resin, epoxy resin, or resin with siloxane bonds such as silicone Materials containing the following can be used.

[0443] In addition, a sealing layer 560 is provided between the substrate 510 and the substrate 570. The sealing layer 560 is provided to seal the substrate 510 from the air. 37(A), it is preferable that the refractive index of the sealing layer 560 side is larger than that of the sealing layer 560 side. When light is extracted from the sealing layer 560, the sealing layer 560 is sandwiched between two members (here, the substrate 5 70 and the substrate 510 (hereinafter also referred to as an optical bonding layer). do.

[0444] A sealant may be formed on the outer periphery of the sealing layer 560. As a result, a light-emitting element is formed in the region surrounded by the substrate 510, the substrate 570, the sealing layer 560, and the sealant. The sealing layer 560 may be formed by filling an inert gas (nitrogen) Alternatively, a desiccant may be placed in the inert gas to remove moisture. The sealing material may be, for example, an epoxy-based It is preferable to use resin or glass frit. In addition, as a material used for the sealing material, water It is preferable to use a material that is impermeable to carbon and oxygen.

[0445] The display device 501 also includes a pixel 502R. The pixel 502R is a light-emitting module It has a 580R.

[0446] The pixel 502R has a light emitting element 550R and is capable of supplying power to the light emitting element 550R. The transistor 502t is a part of the pixel circuit. The light emitting module 580R includes a light emitting element 550R and a colored layer 567R. It has.

[0447] The light emitting element 550R has a lower electrode, an upper electrode, and an EL layer between the lower electrode and the upper electrode. For example, the light-emitting element described in the above embodiment can be used as the light-emitting element 550R. can be done.

[0448] In addition, a microcavity structure is used between the lower electrode and the upper electrode to The light intensity may be increased.

[0449] In addition, when the sealing layer 560 is provided on the side from which light is extracted, the sealing layer 560 550R and the colored layer 567R.

[0450] The colored layer 567R is located so as to overlap the light emitting element 550R. A part of the light emitted by R passes through the colored layer 567R and reaches the light emitting module in the direction of the arrow shown in the figure. It is ejected from the exterior of Lu 580R.

[0451] The display device 501 is also provided with a light-shielding layer 567BM in the light-emitting direction. The colored layer 567BM is provided so as to surround the colored layer 567R.

[0452] The colored layer 567R may have a function of transmitting light in a specific wavelength band. For example, a color filter that transmits light in the red wavelength band and a color filter that transmits light in the green wavelength band are used. -filter, color filter that transmits light in the blue wavelength band, and color filter that transmits light in the yellow wavelength band Each color filter can be made of various materials. Printing, inkjet printing, etching using photolithography technology, etc. It can be formed.

[0453] The display device 501 is also provided with an insulating layer 521. The insulating layer 521 is The insulating layer 521 has a function of flattening the unevenness caused by the pixel circuit. The insulating layer 521 may have a function of suppressing diffusion of impurities. This makes it possible to prevent the reliability of the transistor 502t and the like from being reduced due to the diffusion of impurities.

[0454] The light emitting element 550R is formed above the insulating layer 521. The lower electrode of the substrate is provided with a partition wall 528 that overlaps the edge of the lower electrode. A spacer for controlling the distance between the partition wall 528 and the substrate 570 may be formed on the partition wall 528 .

[0455] The gate line driving circuit 503g(1) includes a transistor 503t and a capacitor element 503c. The driver circuit and the pixel circuit can be formed over the same substrate in the same process.

[0456] Moreover, wiring 511 capable of supplying signals is provided on the substrate 510. A terminal 519 is provided on the wiring 511. The terminal 519 is connected to an FPC 509 (1 ) is connected to FPC509(1). Also, FPC509(1) is connected to the video signal, clock signal, and start signal. It has the function of supplying signals such as a reset signal. A print wiring board (PWB) may be attached.

[0457] In addition, transistors with various structures can be applied to the display device 501. In (A), a case where a bottom gate type transistor is applied is illustrated. However, the present invention is not limited to this. For example, a top-gate transistor shown in FIG. 37(B) may be used. may be applied to the display device 501.

[0458] The configuration of the transistors 502t and 503t is the same as that of the previous embodiment. The description of the condition can be taken into consideration.

[0459] <Explanation about touch sensors> Next, the touch sensor 595 will be described in detail with reference to FIG. ) corresponds to a cross-sectional view taken along the dashed dotted line X3-X4 shown in FIG. 36(B).

[0460] The touch sensor 595 has electrodes 591 and 592 arranged in a staggered pattern on a substrate 590. , an insulating layer 593 covering the electrodes 591 and 592, and wiring connecting the adjacent electrodes 591. 594 and

[0461] The electrode 591 and the electrode 592 are formed using a light-transmitting conductive material. Conductive materials that can be used include indium oxide, indium tin oxide, indium zinc oxide, Conductive oxides such as zinc oxide and zinc oxide doped with gallium can be used. Alternatively, a film containing graphene may be used. The film containing graphene may be formed in a film shape, for example. The film containing graphene oxide can be formed by reducing the film. and methods of applying heat.

[0462] For example, after forming a film of a light-transmitting conductive material on the substrate 590 by sputtering, By using various patterning techniques such as photolithography, unnecessary parts are removed and the A pole 591 and an electrode 592 can be formed.

[0463] The insulating layer 593 may be made of a resin such as acrylic or epoxy, or a silicon dioxide film. In addition to resins with siloxane bonds such as silicon dioxide, silicon oxynitride, and silicon dioxide, Inorganic insulating materials such as aluminum oxide may also be used.

[0464] An opening reaching the electrode 591 is provided in the insulating layer 593, and a wiring 594 is formed on the adjacent electrode 5 The transparent conductive material can increase the aperture ratio of the touch panel. Therefore, it can be suitably used for the wiring 594. In addition, A highly conductive material can be suitably used for the wiring 594 because it can reduce electrical resistance.

[0465] The electrodes 592 extend in one direction, and a plurality of electrodes 592 are provided in a stripe pattern. In addition, the wiring 594 is provided so as to intersect with the electrode 592 .

[0466] A pair of electrodes 591 are provided with one electrode 592 sandwiched therebetween. Pole 591 is connected.

[0467] It should be noted that the plurality of electrodes 591 do not necessarily need to be arranged in a direction perpendicular to one electrode 592. The angle may be greater than 0 degrees but less than 90 degrees.

[0468] The wiring 598 is connected to the electrode 591 or the electrode 592. The wiring 598 is made of, for example, aluminum, gold, platinum, silver, or the like. , nickel, titanium, tungsten, chromium, molybdenum, iron, cobalt, copper, or pascals Metallic materials such as radium and alloy materials containing such metallic materials can be used.

[0469] Note that an insulating layer is provided to cover the insulating layer 593 and the wiring 594 to protect the touch sensor 595. That's fine.

[0470] Furthermore, the connection layer 599 connects the wiring 598 and the FPC 509(2).

[0471] The connection layer 599 is an anisotropic conductive film (ACF). Conductive Film) and Anisotropic Conductive Paste (ACP) Conductive Paste) can be used.

[0472] <Touch panel explanation 2> Next, the touch panel 500 will be described in detail with reference to FIG. ) corresponds to a cross-sectional view taken along the dashed dotted line X5-X6 shown in FIG. 36(A).

[0473] The touch panel 500 shown in FIG. 38(A) includes the display device 501 described in FIG. 37(A), This configuration is made by bonding together the touch sensor 595 described in FIG.

[0474] The touch panel 500 shown in FIG. 38(A) is similar to the touch panel 500 described in FIG. 37(A) and FIG. 37(C). In addition to this configuration, it has an adhesive layer 597 and an anti-reflection layer 567p.

[0475] The adhesive layer 597 is provided in contact with the wiring 594. Note that the adhesive layer 597 is Substrate 590 is bonded to substrate 570 so that 595 overlaps display device 501 . The adhesive layer 597 is preferably transparent. For example, acrylic resin, urethane resin, or ultraviolet curable resin can be used. A tungsten-based resin, an epoxy-based resin, or a siloxane-based resin can be used.

[0476] The anti-reflection layer 567p is provided at a position overlapping the pixel. For example, a circular polarizing plate can be used.

[0477] Next, for a touch panel with a different configuration from that shown in FIG. 38(A), FIG. 38(B) is used. and explain.

[0478] Fig. 38(B) is a cross-sectional view of the touch panel 600. The touch panel shown in Fig. 38(B) 600 is a touch panel for the touch panel 500 shown in FIG. 38(A) and the display device 501. The difference is the location of the sensor 595. The different configurations are explained in detail here, and the same configurations are used. The description of the touch panel 500 is cited for the parts that can be used.

[0479] The colored layer 567R is located at a position overlapping the light emitting element 550R. The optical element 550R emits light toward the side where the transistor 502t is provided. A part of the light emitted by the light emitting element 550R is transmitted through the colored layer 567R and is reflected by the light emitting element 550R as indicated by the arrows in the figure. The light is emitted to the outside of the light emitting module 580R in the direction of .

[0480] The touch sensor 595 is provided on the substrate 510 side of the display device 501.

[0481] The adhesive layer 597 is between the substrate 510 and the substrate 590, and connects the display device 501 and the touch sensor 5 Glue 95 together.

[0482] As shown in Figures 38(A) and 38(B), the light emitted from the light emitting element is incident on the upper and lower surfaces of the substrate. It may be injected in either one or both directions.

[0483] The display device and the electronic device described in this embodiment may employ the structures described in the above embodiments. This allows external correction to be performed in parallel with the display operation. This makes it possible to realize a display device and an electronic device with less unevenness in display. A display device and an electronic device capable of displaying can be realized.

[0484] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments. can.

[0485] (Embodiment 7) In this embodiment, a display module that can use the display device exemplified in the above embodiment will be described. This section explains modules and electronic devices.

[0486] <Appearance of the display device> FIG. 39 is a perspective view showing an example of the appearance of a display device. The display device shown in FIG. It is equipped with a controller, power supply circuit, image processing circuit, image memory, CPU, etc. The panel 251 has a circuit board 252 and a connection part 253. The panel 251 has a plurality of pixels. a pixel section 254 in which a plurality of pixels are arranged, a driver circuit 255 for selecting a plurality of pixels for each row, and a driver circuit 256 for driving the selected row. and a driver circuit 256 for controlling the input of video signals to the pixels within the display panel.

[0487] Various signals and power supply potentials are transmitted from the circuit board 252 to the panel 25 via the connection portion 253. 1. The connection part 253 is connected to an FPC (Flexible Printed Circuit) In addition, when a COF tape is used for the connection part 253, In this case, a part of the circuit in the circuit board 252 or the driving circuit 255 or driving A part of the circuit 256 is formed on a separately prepared chip, and then COF (Chip On Fly) is formed. The chip may be connected to the COF tape using a COF (Copper on Film) method.

[0488] <Example of electronic device configuration> The display device shown in the above embodiment is applicable to a display device, a notebook personal computer, a recording medium, Image playback devices equipped with recording media (typically DVD: Digital Versatile A device that plays back recording media such as discs and has a display that can display the images In addition, the display device shown in the above embodiment mode can be used. Examples of electronic devices that can be used include mobile phones, portable game consoles, personal digital assistants, e-book readers, and video cameras. cameras, digital still cameras, goggle-type displays (head-mounted displays) displays), navigation systems, sound reproduction devices (car audio, digital audio audio players, copiers, fax machines, printers, printer-combined machines, cash machines Examples of electronic devices include ATMs and vending machines. Shown in Figure 40.

[0489] FIG. 40A shows a display device, which includes a housing 301, a display portion 302, a support base 303, and the like. The display device described in the above embodiment can be used for the display portion 302. The equipment includes all information such as for personal computers, TV broadcast reception, and advertising displays. A display device for display is included.

[0490] FIG. 40(B) shows a portable information terminal, which includes a housing 311, a display unit 312, operation keys 313, etc. The display device described in the above embodiment mode can be used for the display portion 312.

[0491] FIG. 40C shows a display device, which includes a curved housing 341, a display portion 342, and the like. By using a flexible substrate in the display device shown in the above embodiment, it is possible to mount the display device in a curved housing. The display device can be used in a display unit 342 supported by a flexible body 341. Moreover, it is possible to provide a display device that is light and easy to use.

[0492] FIG. 40D shows a portable game machine, which includes a housing 321, a housing 322, a display unit 323, and a display unit 324. 324, microphone 325, speaker 326, operation keys 327, stylus 328, etc. The display device described in the above embodiment has the display portion 323 or the display portion 324. The display unit 323 or the display unit 324 may be configured with the display device shown in the above embodiment. By using this device, it is possible to create a portable game machine that is excellent in user experience and is less likely to experience degradation in quality. The portable game machine shown in FIG. 40(D) ​​has two display units. 323 and display unit 324, but the number of display units that a portable game machine has is Not limited.

[0493] FIG. 40(E) shows an electronic book terminal, which includes a housing 331, a display unit 332, etc. The display device shown in this form can be used for the display portion 332. By using a substrate having such a property, the display device can be made flexible. It is possible to provide a lightweight and easy-to-use electronic book terminal.

[0494] FIG. 40(F) shows a mobile phone, which includes a housing 351, a display unit 352, a microphone 357, a speaker, and the like. It is provided with a keyboard 354, a camera 353, an external connection section 356, and operation buttons 355. The display device described in the above embodiment can be used for the display portion 352. When the display device shown in the embodiment mode is formed on a flexible substrate, as shown in FIG. The display device can be applied to a display unit 352 having such a curved surface.

[0495] By using the display device described in the above embodiment in the electronic device described in this embodiment, This allows external correction to be performed in parallel with the operation. This allows for the realization of electronic devices with less distortion. It is possible to realize a child device.

[0496] The structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. It is possible.

[0497] (Notes regarding the present specification) The above-described embodiments and the respective components in the embodiments will be described below with additional notes.

[0498] <Additional Notes Regarding One Aspect of the Present Invention Described in the Embodiments> The configurations shown in each embodiment may be combined with the configurations shown in other embodiments to form one embodiment of the present invention. In addition, when multiple configuration examples are shown in one embodiment, The configuration examples can be appropriately combined with each other.

[0499] Note that the content (or even a part of the content) described in one embodiment may be used in conjunction with that embodiment. Other content (or even part of content) described in the above, and / or one or more other implementations The content (or part of the content) described in the form of You can do things like:

[0500] The contents described in the embodiments are explained in detail in each embodiment using various drawings. This refers to the content that is stated or the content that is stated using the text in the specification.

[0501] In addition, a drawing (or a part thereof) described in one embodiment may be different from another part of the drawing, Another figure (or a part thereof) described in the embodiment, and / or one or more By combining with the figure (or a part thereof) described in another embodiment of the present invention, , and many more diagrams can be constructed.

[0502] Although one aspect of the present invention has been described in each embodiment, one aspect of the present invention is not limited to these. For example, as one aspect of the present invention, the display element in the above embodiment is Although the structure using a light-emitting element has been described, one embodiment of the present invention is not limited thereto. Depending on the situation, other display elements, such as liquid crystal elements, may be used. In the embodiment, the configuration for reading out information on the threshold voltage during the blanking period has been described. However, one aspect of the present invention is not limited to this. In the above embodiment, the information of the transistor may be read out. The configuration for reading out information on the current characteristics of the pixel driving transistor has been explained above. One embodiment of the present invention is not limited to this. Alternatively, the information on the current characteristics of the transistor may be read out. In some cases, the information on the current characteristics of the transistor may not be read out. In some cases or depending on the situation, external correction may not be necessary.

[0503] <Notes regarding the description explaining the drawings>

[0504] In this specification, the terms "above" and "below" that indicate the positional relationship between components are used. are used for convenience in describing the drawings. Therefore, the terms indicating the arrangement may be changed as appropriate depending on the direction in which the arrangement is depicted. The terms are not limited to those described above and can be rephrased appropriately depending on the situation.

[0505] In addition, the terms "above" and "below" refer to the positional relationship of a component that is directly above or directly below and directly connected to it. For example, if the expression is "electrode B on insulating layer A," The electrode B does not need to be formed directly on the insulating layer A, and the insulating layer A and the electrode B This does not exclude the inclusion of other components in between.

[0506] In the present specification and the like, in the block diagrams, the components are classified by function and are independent of each other. However, in actual circuits, components are divided into blocks according to their functions. It is difficult to separate them, and there are cases where multiple functions are involved in one circuit, or where multiple circuits are involved. Therefore, the blocks in the block diagram may be different from those described in the specification. The components are not limited to those described above, and may be rephrased appropriately depending on the situation.

[0507] In addition, in the drawings, the size, thickness of a layer, or area is shown arbitrarily for the convenience of explanation. Therefore, the drawings are not necessarily limited to the scale. The drawings are merely schematic illustrations for the purpose of clarity, and are not limited to the shapes or values ​​shown in the drawings. Signal, voltage, or current variations due to noise, or signals due to timing deviations , voltage, or current variations, etc.

[0508] In addition, in the drawings, top views (also called plan views or layout views) and perspective views, In order to clarify the drawings, some components may be omitted.

[0509] <Notes on possible paraphrases>

[0510] In this specification and the like, when describing the connection relationship of a transistor, one of the source and the drain is referred to as "one of the source and drain" (or the first electrode, or the first terminal), and The other side of the drain is referred to as the "other side of the source or drain" (or second electrode, or second terminal). This means that the source and drain of a transistor are This is because it changes depending on the conditions. Regarding the names of the source and drain of a transistor, can be appropriately rephrased as source (drain) terminal, source (drain) electrode, etc. depending on the situation. It can be done.

[0511] In addition, the terms "electrode" and "wiring" used in this specification and the like do not limit the functionality of these components. For example, an "electrode" may be used as part of a "wiring." Furthermore, the terms "electrode" and "wiring" are used interchangeably to refer to the plural "electrodes" and "wirings." This also includes cases where the "line" is formed as a single unit.

[0512] In this specification and the like, the terms voltage and potential can be interchanged as appropriate. For example, the reference potential is the ground potential (earth potential). If we use the term "ground potential" (potential), we can translate voltage into potential. Note that the potential is relative, and the distribution may differ depending on the reference potential. The potential applied to the wires may be changed.

[0513] In this specification, the terms "film" and "layer" may be used in some cases or depending on the situation. For example, the term "conductive layer" can be used interchangeably with "conductive layer" It may be possible to change the term to "conductive film." Alternatively, for example, In some cases, it may be possible to change the term to "insulating layer."

[0514] <Notes on definitions of terms> The following provides definitions of terms not mentioned in the above embodiments.

[0515] [About Switch] In this specification, a switch is a device that can be in a conducting state (ON state) or a non-conducting state (OFF state). It refers to a device that has the function of controlling whether or not current flows by entering a state where it is in a non-transitory state. A switch is a device that has the function of selecting and switching a path through which current flows.

[0516] For example, an electrical switch or a mechanical switch can be used. The switch is not limited to a specific one as long as it can control the current.

[0517] An example of an electrical switch is a transistor (e.g., a bipolar transistor, M OS transistors, etc.), diodes (e.g., PN diodes, PIN diodes, Schottky diode, MIM (Metal Insulator Metal) diode MIS (Metal Insulator Semiconductor) diodes diode-connected transistors), or logic circuits that combine these. be.

[0518] When a transistor is used as a switch, the "conduction state" of the transistor is This refers to a state in which the source and drain of a transistor can be considered to be electrically short-circuited. The "non-conducting state" of a transistor means that the source and drain of the transistor are electrically isolated. In addition, when a transistor is operated simply as a switch, In this case, the polarity (conductivity type) of the transistor is not particularly limited.

[0519] An example of a mechanical switch is a digital micromirror device (DMD). There are switches that use MEMS (microelectromechanical systems) technology. The switch has a mechanically movable electrode, and the movement of the electrode Thus, the device operates by controlling conduction and non-conduction.

[0520] [Channel length] In this specification and the like, the channel length is, for example, the length of a semiconductor (or the part of the semiconductor through which current flows when the transistor is on) and the gate The distance between the source and drain in the overlapping region, or the region where the channel is formed This refers to

[0521] In one transistor, the channel length does not necessarily have the same value in all regions. That is, the channel length of a transistor may not be fixed to a single value. Therefore, in this specification, the channel length is defined as the length of any one of the regions where the channel is formed. The value may be a maximum, minimum or average value.

[0522] [About channel width] In this specification, the channel width is, for example, the width of a semiconductor (or a transistor when it is in an on-state) The area where the gate electrode overlaps with the gate electrode, or the channel This refers to the length of the portion where the source and drain face each other in the region where the source and drain are formed.

[0523] In one transistor, the channel width does not necessarily have the same value in all regions. That is, the channel width of a transistor may not be fixed to a single value. Therefore, in this specification, the channel width is defined as any one of the widths in the region where the channel is formed. The value, maximum value, minimum value or average value.

[0524] [About pixels] In this specification, a pixel refers to, for example, one element whose brightness can be controlled. Therefore, as an example, one pixel refers to one color element, and one color element Therefore, the brightness is expressed as R (red), G (green), and B (blue). In the case of a color display device, the smallest unit of an image is a triplet of R, G, and B pixels. It is assumed to be composed of elements.

[0525] The color elements are not limited to three colors, and may be more than three. For example, RGBW (W is white) , and RGB with the addition of yellow, cyan, and magenta. [Explanation of symbols]

[0526] 11 Drive circuit 12 Drive circuit 13 Circuit section 14 Output control circuit 15 Pixel section 16 circuits 17 circuits 19a Switch 19b Switch 20 pixels 21 Transistor 22 transistor 23 Transistor 24 Light-emitting element 25 Capacitor element 26 Switch 30a op amp 30b Op Amp 30c op amp 31 Switch 32 Capacitor element 33 Resistive element 41 Switch 43 Latch Circuit 44 Switch 45 Switch 46 Switch 47 Inverter 48 inverters 49 Inverter 70 pixels 71 Transistor 72 transistors 73 Transistor 74 Light-emitting element 75 Capacitor 76 Switch 80 Display device 81 Correction circuit 82 Image processing circuit 83 CPU 85 Panels 86 Controller 87 Image Memory 88 memory 89 Image data 100A transistor 100B transistor 100C transistor 100D transistor 100E transistor 100F transistor 100G transistor 101 Substrate 102 Conductive film 103 Oxide semiconductor film 104 Conductive film 105 Conductive film 106 insulating film 107 Conductive film 111 insulating film 111a nitride insulating film 111b Oxide insulating film 112 Oxide semiconductor film 112a area 112b area 112c area 112d area 112e Offset area 113a Oxide semiconductor film 113b Oxide semiconductor film 113c Oxide semiconductor film 114 Conductive film 114a Conductive film 114b Conductive film 114c conductive film 116 Conductive film 116a Conductive film 116b Conductive film 116c conductive film 117 Insulating film 117a Insulating film 118 Conductive film 118a Conductive film 118b Conductive film 120 insulating film 121 PCB 122 insulating film 123 Oxide semiconductor film 123a area 123b area 123c area 123d area 124 insulating film 125 Conductive Film 126 Conductive Film 127 Conductive Film 128 insulating film 129 insulating film 130a opening 130b opening 131 Circuit Board 132 insulating film 133 Oxide semiconductor film 133b area 133c area 133d area 133e Offset area 134 insulating film 134a Insulating film 135 Conductive film 136 Conductive film 137 Conductive Film 137a Conductive film 138 insulating film 139 Insulating Film 140a opening 140b opening 200 boards 201 Conductive film 203 Conductive Film 204 Semiconductor Film 205 Conductive Film 206 Conductive Film 207 Semiconductor Film 209 Conductive Film 210 Conductive film 212 Conductive film 213 Conductive Film 215 insulating film 216 Insulating film 217 Insulating Film 218 Insulating film 219 Insulating Film 220 insulating film 225 insulating film 226 Insulating Film 227 EL layer 228 Conductive Film 230 PCB 231 Shielding membrane 232 Colored layer 251 Panel 252 Circuit Board 253 Connection 254 pixel section 255 drive circuit 256 drive circuit 301 Case 302 Display section 303 Support stand 311 Case 312 Display section 313 Operation Key 321 Case 322 Case 323 Display section 324 Display section 325 Microphone 326 Speakers 327 Operation Key 328 Stylus 331 Case 332 Display section 341 Case 342 Display section 351 Case 352 Display section 353 Camera 354 Speakers 355 Button 356 External connection part 357 Mike 401 Conductive layer 401a Conductive layer 401b Conductive layer 402 Conductive layer 403a Conductive layer 403b Conductive layer 403c conductive layer 404 Conductive layer 405 Conductive Layer 406 Conductive layer 407 Conductive Layer 411 Semiconductor layer 412 Semiconductor layer 413 Semiconductor layer 500 touch panel 501 Display device 502R pixels 502t transistor 503c Capacitive element 503g Gate line driving circuit 503t transistor 509 FPC 510 board 510a Insulating layer 510b flexible substrate 510c adhesive layer 511 Wiring 519 terminal 520 Oxide semiconductor layer 521 Insulating layer 528 Bulkhead 550R light emitting element 560 Sealing Layer 567BM light shielding layer 567p anti-reflection layer 567R colored layer 570 PCB 570a Insulating layer 570b flexible substrate 570c ​​adhesive layer 580R Light Emitting Module 590 PCB 591 Electrode 592 Electrode 593 Insulating Layer 594 Wiring 595 Touch Sensor 597 Adhesive layer 598 Wiring 599 Connection Layer 600 touch panel

Claims

1. A display device including a transistor, a capacitor, and a light-emitting element, a first insulating film; an oxide semiconductor film having a region in contact with a top surface of the first insulating film and having a channel formation region of the transistor; a second insulating film having a region in contact with an upper surface of the oxide semiconductor film and functioning as a gate insulating film; a first conductive film having a region in contact with an upper surface of the second insulating film and functioning as a gate electrode of the transistor; a third insulating film having a region in contact with an upper surface of the oxide semiconductor film; a second conductive film having a region in contact with a top surface of the oxide semiconductor film and functioning as a source electrode of the transistor; a third conductive film having a region in contact with a top surface of the oxide semiconductor film and functioning as a drain electrode of the transistor; a fourth insulating film having a region in contact with an upper surface of the third insulating film, the second conductive film does not have a region that overlaps with the first conductive film over the oxide semiconductor film, the second conductive film does not have a region that overlaps with the second insulating film over the oxide semiconductor film, the third conductive film does not have a region that overlaps with the first conductive film over the oxide semiconductor film, the third conductive film does not have a region that overlaps with the second insulating film over the oxide semiconductor film, the first conductive film, the second conductive film, and the third conductive film each have the same metal material; the second insulating film has a region that protrudes beyond an end of the first conductive film in a cross-sectional view in a channel length direction of the transistor, one electrode of the capacitor element has a region in contact with an upper surface of the first insulating film and is made of the same material as the oxide semiconductor film; the other electrode of the capacitor element has a region that is in contact with one of the second conductive film and the third conductive film through a contact hole; one electrode of the light-emitting element has a region overlapping with one electrode of the capacitor element via the fourth insulating film, a display device in which one electrode of the light-emitting element has a region overlapping with the other electrode of the capacitive element via the fourth insulating film;

2. A display device including a transistor, a capacitor, and a light-emitting element, a first insulating film; an oxide semiconductor film having a region in contact with a top surface of the first insulating film and having a channel formation region of the transistor; a second insulating film having a region in contact with an upper surface of the oxide semiconductor film and functioning as a gate insulating film; a first conductive film having a region in contact with an upper surface of the second insulating film and functioning as a gate electrode of the transistor; a third insulating film having a region in contact with an upper surface of the oxide semiconductor film, a region in contact with a side surface of the oxide semiconductor film, a region in contact with an upper surface of the second insulating film, and a region in contact with a side surface of the second insulating film; a second conductive film having a region in contact with a top surface of the oxide semiconductor film and functioning as a source electrode of the transistor; a third conductive film having a region in contact with a top surface of the oxide semiconductor film and functioning as a drain electrode of the transistor; a fourth insulating film having a region in contact with an upper surface of the third insulating film, the second conductive film does not have a region that overlaps with the first conductive film over the oxide semiconductor film, the second conductive film does not have a region that overlaps with the second insulating film over the oxide semiconductor film, the third conductive film does not have a region that overlaps with the first conductive film over the oxide semiconductor film, the third conductive film does not have a region that overlaps with the second insulating film over the oxide semiconductor film, the first conductive film, the second conductive film, and the third conductive film each have the same metal material; the second insulating film has a region that protrudes beyond an end of the first conductive film in a cross-sectional view in a channel length direction of the transistor, one electrode of the capacitor element has a region in contact with an upper surface of the first insulating film and is made of the same material as the oxide semiconductor film; the other electrode of the capacitor element has a region that is in contact with one of the second conductive film and the third conductive film through a contact hole; one electrode of the light-emitting element has a region overlapping with one electrode of the capacitor element via the fourth insulating film, a display device in which one electrode of the light-emitting element has a region overlapping with the other electrode of the capacitive element via the fourth insulating film;

3. In claim 1 or claim 2, each of the first conductive film, the second conductive film, and the third conductive film has a first layer and a second layer on the first layer; the first layer comprises an alloy of molybdenum and titanium; The second layer comprises copper.

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