Display device

Abstract

A display device having a function of sensing an object in contact with or in proximity to a display portion is provided.SOLUTION: The display device includes a light-emitting element and a light-receiving element. The light-emitting element includes a first pixel electrode, a first light-emitting layer over the first pixel electrode, an intermediate layer over the first light-emitting layer, a second light-emitting layer over the intermediate layer, and a common electrode over the second light-emitting layer. The light-receiving element includes a second pixel electrode, a light-receiving layer over the second pixel electrode, and a common electrode over the light-receiving layer. The first light-emitting layer and the second light-emitting layer have a function of emitting light of the same color.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] FIELD OF THE INVENTION One embodiment of the present invention relates to a display device and a manufacturing method of the display device.

[0002] Note that one embodiment of the present invention is not limited to the above technical field. Examples of the technical field of one embodiment of the present invention disclosed in this specification and the like include semiconductor devices, display devices, light-emitting devices, power storage devices, memory devices, electronic devices, lighting devices, input devices, input / output devices, driving methods thereof, and manufacturing methods thereof. A semiconductor device refers to any device that can function by utilizing semiconductor characteristics. [Background technology]

[0003] In recent years, display devices have been used in a variety of devices, including information terminal devices such as smartphones, tablet devices, and laptop PCs, as well as television devices and monitor devices. In addition, there is a demand for display devices that not only display images but also have various additional functions, such as a touch sensor function or a function for capturing fingerprint images for authentication.

[0004] As a display device, for example, a light-emitting device having a light-emitting element (also called a light-emitting device) has been developed. In particular, a light-emitting element (also called an EL element or an EL device) utilizing the electroluminescence (EL) phenomenon has features such as being easily thin and lightweight, being capable of high-speed response to an input signal, and being capable of being driven by a DC constant voltage power supply, and is therefore applied to a display device. For example, Patent Document 1 discloses a flexible light-emitting device using an organic EL element (also called an organic EL device). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-197522 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of one embodiment of the present invention is to provide a display device having a function of detecting an object in contact with or close to a display portion, and a manufacturing method thereof.An object of one embodiment of the present invention is to provide a display device having a function of performing authentication, and a manufacturing method thereof.An object of one embodiment of the present invention is to provide a display device with a high aperture ratio, and a manufacturing method thereof.An object of one embodiment of the present invention is to provide a small-sized display device, and a manufacturing method thereof.An object of one embodiment of the present invention is to provide a highly reliable display device, and a manufacturing method thereof.An object of one embodiment of the present invention is to provide a novel display device, and a manufacturing method thereof.

[0007] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that problems other than these can be extracted from the description of the specification, drawings, claims, etc. [Means for solving the problem]

[0008] One embodiment of the present invention is a display device including a light-emitting element and a light-receiving element. The light-emitting element includes a first pixel electrode, a first light-emitting layer over the first pixel electrode, an intermediate layer over the first light-emitting layer, a second light-emitting layer over the intermediate layer, a common layer over the second light-emitting layer, and a common electrode over the common layer. The light-receiving element includes a second pixel electrode, a light-receiving layer over the second pixel electrode, a common layer over the light-receiving layer, and a common electrode over the common layer. The common layer functions as either a hole-injection layer or an electron-injection layer in the light-emitting element, and the common layer functions as either a hole-transport layer or an electron-transport layer in the light-receiving element.

[0009] Alternatively, in the above embodiment, the first light-emitting layer and the second light-emitting layer may have the function of emitting light of the same color.

[0010] Alternatively, in the above aspect, the semiconductor device may include a first transistor and a second transistor, one of a source or a drain of the first transistor being electrically connected to a first pixel electrode, one of a source or a drain of the second transistor being electrically connected to a second pixel electrode, and the first transistor and the second transistor may have silicon or a metal oxide in a channel formation region.

[0011] Alternatively, one embodiment of the present invention is a method for manufacturing a semiconductor device including: a first step of forming a first pixel electrode, a second pixel electrode, and a connection electrode; a second step of forming a first light-emitting film, an intermediate film, and a second light-emitting film, in this order, on the first pixel electrode and the second pixel electrode; a third step of forming a first sacrificial film on the second light-emitting film and on the connection electrode; and a third step of etching the first sacrificial film, the second light-emitting film, the intermediate film, and the first light-emitting film to expose the second pixel electrode, and forming a first light-emitting layer on the first pixel electrode, a first intermediate film on the first light-emitting layer, a second light-emitting layer on the intermediate film, and a third step of forming a second light-emitting layer on the second light-emitting layer. a fourth step of forming a first sacrificial layer on the second light-emitting layer and on the connecting electrode; a fifth step of forming a light-receiving film on the first sacrificial layer and on the second pixel electrode; a sixth step of forming a second sacrificial film on the light-receiving film; a seventh step of etching the second sacrificial film and the light-receiving film to form a light-receiving layer on the second pixel electrode and a second sacrificial layer on the light-receiving layer; an eighth step of removing the first sacrificial layer and the second sacrificial layer; and a ninth step of forming a common electrode on the second light-emitting layer and on the light-receiving layer so as to have a region in contact with the connecting electrode.

[0012] Alternatively, in the above embodiment, the first light-emitting film, the second light-emitting film, and the light-receiving film may be formed by a vapor deposition method using a shielding mask.

[0013] Alternatively, in the above aspect, the first sacrificial film and the second sacrificial film may comprise the same metal film, alloy film, metal oxide film, semiconductor film, or inorganic insulating film, and in the fourth step, the first luminescent film and the second luminescent film may be etched by dry etching using an etching gas that does not contain oxygen as a main component, and in the eighth step, the first sacrificial layer and the second sacrificial layer may be removed by wet etching using a tetramethylammonium hydroxide aqueous solution, dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture thereof.

[0014] Alternatively, in the above aspect, the first sacrificial film and the second sacrificial film may contain aluminum oxide.

[0015] Alternatively, in the above embodiment, a tenth step of forming a protective layer on the common electrode may be included after the ninth step. [Effects of the Invention]

[0016] According to one embodiment of the present invention, a display device having a function of detecting an object in contact with or close to a display portion and a manufacturing method thereof can be provided. According to one embodiment of the present invention, a display device having a function of performing authentication and a manufacturing method thereof can be provided. According to one embodiment of the present invention, a display device with a high aperture ratio and a manufacturing method thereof can be provided. According to one embodiment of the present invention, a small-sized display device and a manufacturing method thereof can be provided. According to one embodiment of the present invention, a highly reliable display device and a manufacturing method thereof can be provided. According to one embodiment of the present invention, a novel display device and a manufacturing method thereof can be provided.

[0017] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Note that effects other than these can be extracted from the description in the specification, drawings, claims, etc. [Brief explanation of the drawings]

[0018] [Figure 1]1A to 1E are cross-sectional views showing examples of the configuration of a display device, and Fig. 1F is a diagram showing an example of a captured image. [Figure 2] 2A and 2B are cross-sectional views showing configuration examples of a display device. [Figure 3] 3A and 3B are cross-sectional views showing configuration examples of a display device. [Figure 4] FIG. 4 is a cross-sectional view showing an example of the configuration of a display device. [Figure 5] 5A and 5B are cross-sectional views showing configuration examples of a display device. [Figure 6] 6A to 6C are cross-sectional views showing examples of the configuration of a display device. [Figure 7] 7A and 7B are top views showing configuration examples of the display device. [Figure 8] 8A and 8B are top views showing configuration examples of the display device. [Figure 9] Fig. 9A is a top view showing an example of the configuration of a display device, and Fig. 9B is a diagram showing the light receiving range of a light receiving element. [Figure 10] FIG. 10 is a top view showing an example of the configuration of a display device. [Figure 11] 11A to 11E are cross-sectional views showing examples of the configuration of a display device. [Figure 12] 12A to 12D are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 13] 13A to 13C are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 14] 14A to 14D are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 15] 15A to 15C are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 16] FIG. 16 is a perspective view showing an example of the configuration of a display device. [Figure 17] FIG. 17 is a cross-sectional view showing an example of the configuration of a display device. [Figure 18] FIG. 18 is a cross-sectional view showing an example of the configuration of a display device. [Figure 19]FIG. 19 is a cross-sectional view showing an example of the configuration of a display device. [Figure 20] FIG. 20 is a cross-sectional view showing an example of the configuration of a display device. [Figure 21] FIG. 21 is a cross-sectional view showing an example of the configuration of a display device. [Figure 22] 22A and 22B are diagrams showing an example of an electronic device. [Figure 23] 23A and 23B are diagrams showing an example of an electronic device. [Figure 24] 24A to 24E are diagrams showing an example of an electronic device. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments will be described with reference to the drawings. However, it will be readily understood by those skilled in the art that the embodiments can be implemented in many different ways and that various changes in form and details can be made without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the following description of the embodiments.

[0020] In the configuration of the invention described below, the same parts or parts having similar functions are denoted by the same reference numerals in different drawings, and repeated explanations thereof will be omitted. Furthermore, when referring to similar functions, the same hatching pattern may be used and no particular reference numeral may be assigned.

[0021] In the drawings described in this specification, the size of each component, the thickness of a layer, or an area may be exaggerated for clarity, and therefore, the drawings are not necessarily limited to the scale.

[0022] In this specification, ordinal numbers such as "first" and "second" are used to avoid confusion of components and do not limit the number.

[0023] Furthermore, in this specification and the like, the terms "film" and "layer" are interchangeable. For example, the terms "conductive layer" and "insulating layer" may be interchangeable with the terms "conductive film" and "insulating film."

[0024] In this specification and the like, the EL layer refers to a layer provided between a pair of electrodes of a light-emitting element and containing at least a light-emitting substance (also referred to as a light-emitting layer), or a stack including a light-emitting layer.

[0025] In this specification and the like, a display panel, which is one aspect of a display device, has a function of displaying (outputting), for example, an image on a display surface, and therefore is one aspect of an output device.

[0026] In addition, in this specification, a display panel having a connector such as an FPC (Flexible Printed Circuit) or TCP (Tape Carrier Package) attached to the substrate, or having an IC mounted on the substrate using a COG (Chip On Glass) method or the like, may be referred to as a display panel module, display module, or simply a display panel, etc.

[0027] (Embodiment 1) In this embodiment, a structural example of a display device according to one embodiment of the present invention and an example of a method for manufacturing the display device will be described.

[0028] A display device according to one embodiment of the present invention has a display portion in which pixels are arranged in a matrix. Each pixel includes a plurality of subpixels, each of which includes a light-emitting element (also referred to as a light-emitting device). The subpixels in the same pixel can emit light of different colors.

[0029] Each light-emitting element has a pair of electrodes and a light-emitting layer between them. The light-emitting element is preferably an organic EL element (organic electroluminescent element). Two or more light-emitting elements that emit different colors have light-emitting layers containing different materials. For example, a full-color display device can be realized by having three types of light-emitting elements that emit red (R), green (G), or blue (B) light, respectively.

[0030] Here, when creating separate light-emitting layers for light-emitting elements of different colors, it is known to form them by a vapor deposition method using a shadow mask such as a metal mask. However, with this method, various factors, such as the accuracy of the metal mask, misalignment between the metal mask and the substrate, deflection of the metal mask, and the spread of the contours of the deposited film due to, for example, vapor scattering, can cause deviations in the shape and position of the island-shaped organic film from the design, making it difficult to achieve high definition and a high aperture ratio. For this reason, measures have been taken to artificially increase the definition (also known as pixel density), such as by applying a special pixel arrangement method such as a pentile arrangement.

[0031] In one embodiment of the present invention, a light-emitting layer is processed into a fine pattern without using a shadow mask such as a metal mask. This allows subpixels to be made finer than when light-emitting layers are separately formed using a shadow mask, thereby increasing the pixel aperture ratio. Furthermore, because light-emitting layers can be separately formed, a display device with extremely vivid, high-contrast, and high display quality can be realized.

[0032] By miniaturizing the subpixels, subpixels that do not contribute to display can be provided in the pixel. For example, in addition to subpixels having a light-emitting element, subpixels having a light-receiving element (also referred to as a light-receiving device) can be provided in the pixel. Even in this case, the display device of one embodiment of the present invention can prevent the pixel density from becoming low. For example, the pixel density can be set to 400 ppi or more, 1000 ppi or more, 3000 ppi or more, or 5000 ppi or more.

[0033] The light-receiving element included in the display device of one embodiment of the present invention functions as an optical sensor. Therefore, the display device of one embodiment of the present invention can display an image using a light-emitting element and detect an object in contact with or near the display portion using the light-receiving element. Furthermore, when a user's finger touches the display portion, the display device of one embodiment of the present invention can perform authentication based on a fingerprint of the finger.

[0034] By providing the light receiving element in the display section, it is not necessary to attach a sensor externally to the display device, and therefore the number of components in the display device can be reduced, making it possible to make the display device smaller and lighter.

[0035] In addition, in the display device of one embodiment of the present invention, a light-receiving element can detect light that is emitted from a light-emitting element, irradiated onto an object, and reflected by the object. Therefore, even in a dark place, for example, an object in contact with or close to the display unit can be detected, and authentication such as fingerprint authentication can be performed.

[0036] In this specification, etc., a device fabricated using a metal mask or FMM (fine metal mask, high-resolution metal mask) may be referred to as a device with an MM (metal mask) structure. In addition, in this specification, etc., a device fabricated without using a metal mask or FMM may be referred to as a device with an MML (metal maskless) structure.

[0037] In this specification etc., a structure in which different light-emitting layers are made for light-emitting elements of each color (here, blue (B), green (G), and red (R)), or in which the light-emitting layers are painted differently, may be referred to as an SBS (Side By Side) structure. In addition, in this specification etc., a light-emitting element that can emit white light may be referred to as a white light-emitting element. In addition, a white light-emitting element can be combined with a colored layer (for example, a color filter) to realize a display device that displays full color.

[0038] Furthermore, light-emitting elements can be broadly classified into a single structure and a tandem structure. A light-emitting element with a single structure has one light-emitting unit between a pair of electrodes, and the light-emitting unit preferably includes one or more light-emitting layers. To obtain white light emission, two or more light-emitting layers may be selected so that the light emitted from each of the two or more light-emitting layers has a complementary color relationship. For example, by making the light-emitting color of the first light-emitting layer and the light-emitting color of the second light-emitting layer complementary to each other, a configuration that emits white light as a whole can be obtained. The same applies to a light-emitting element having three or more light-emitting layers.

[0039] A light-emitting element with a tandem structure preferably has two or more light-emitting units between a pair of electrodes, and each light-emitting unit preferably includes one or more light-emitting layers. To obtain white light emission, light from the light-emitting layers of multiple light-emitting units may be combined to obtain white light emission. The structure for obtaining white light emission is the same as that of the single structure. In a light-emitting element with a tandem structure, it is preferable to provide an intermediate layer such as a charge generation layer between the multiple light-emitting units.

[0040] Furthermore, when comparing the above-mentioned white light-emitting element (single structure or tandem structure) with a light-emitting element having an SBS structure, the light-emitting element having an SBS structure can reduce power consumption compared to the white light-emitting element. Therefore, when it is desired to reduce the power consumption of a display device, it is preferable to use a light-emitting element having an SBS structure. On the other hand, since the manufacturing process of a white light-emitting element is simpler than that of a light-emitting element having an SBS structure, it is possible to reduce manufacturing costs or increase manufacturing yields.

[0041] 1A to 1E are cross-sectional views illustrating structural examples of a display device according to one embodiment of the present invention.

[0042] A display device 10A shown in FIG. 1A has, between a substrate 51 and a substrate 59, a layer 53 having a light receiving element and a layer 57 having a light emitting element.

[0043] A display device 10B shown in FIG. 1B has, between a substrate 51 and a substrate 59, a layer 55 having transistors, a layer 53 having light receiving elements, and a layer 57 having light emitting elements.

[0044] The display device 10A and the display device 10B are configured such that red (R), green (G), and blue (B) light is emitted from a layer 57 having light-emitting elements.

[0045] In one embodiment of the present invention, a display portion includes a plurality of pixels arranged in a matrix. Each pixel includes one or more subpixels. Each subpixel includes one light-emitting element or one light-receiving element. For example, a pixel may include four subpixels. Specifically, each pixel may include light-emitting elements of three colors, R, G, and B, and a light-receiving element. Alternatively, each pixel may include light-emitting elements of three colors, yellow (Y), cyan (C), and magenta (M), and a light-receiving element. Alternatively, each pixel may include five subpixels. Specifically, each pixel may include light-emitting elements of four colors, R, G, B, and white (W), and a light-receiving element. Alternatively, each pixel may include light-emitting elements of four colors, R, G, B, and infrared (IR), and a light-receiving element. Note that a light-receiving element may be provided in all or some of the pixels. Furthermore, each pixel may include multiple light-receiving elements.

[0046] The display device according to one embodiment of the present invention may have a function of detecting an object, such as a finger, in contact with the display device. For example, as shown in FIG. 1C , light emitted from a light-emitting element in a layer 57 having a light-emitting element is reflected by a finger 52 in contact with the display device 10B, and the light-receiving element in a layer 53 having a light-receiving element detects the reflected light. This makes it possible to detect that the finger 52 has touched the display device 10B. As shown in FIG. 1D , light emitted from a light-emitting element in the layer 57 is reflected by a finger 52 approaching the display device 10B, and the light-receiving element in the layer 53 detects the reflected light. This makes it possible to detect that the finger 52 has approached the display device 10B. That is, the display device according to one embodiment of the present invention can function as a touch sensor (also referred to as a direct touch sensor) and a near-touch sensor (also referred to as a hover sensor, hover touch sensor, non-contact sensor, or touchless sensor).

[0047] As described above, for example, if the display device 10B functions as a near-touch sensor, the finger 52 can be detected when the finger 52 is close to the display device 10B, even if the finger 52 does not touch the display device 10B. For example, it is preferable that the display device 10B be configured to detect the finger 52 when the distance between the display device 10B and the finger 52 is in the range of 0.1 mm to 300 mm, preferably 3 mm to 50 mm. This configuration allows the finger 52 to operate the display device 10B without directly touching it, in other words, allows the display device 10B to be operated in a contactless (touchless) manner. This configuration reduces the risk of the display device 10B becoming dirty or scratched. Furthermore, the display device 10B can be operated with the finger 52 while preventing the finger 52 from directly touching the display device 10B with dirt (e.g., dust, viruses, etc.).

[0048] Furthermore, the display device of one embodiment of the present invention can have a function of detecting, for example, a fingerprint of a finger 52. Fig. 1E is a schematic enlarged view of a contact portion when a finger 52 is in contact with a substrate 59. Fig. 1E also shows that a layer 57 having a light-emitting element and a layer 53 having a light-receiving element are alternately arranged.

[0049] A fingerprint is formed by concave and convex portions of finger 52. Therefore, the convex portions of the fingerprint are in contact with substrate 59 as shown in FIG.

[0050] Light reflected from a surface or interface can be classified into specular reflection and diffuse reflection. Specular reflection is highly directional light, with the angle of incidence and the angle of reflection matching, while diffuse reflection is low-directional light, with low angular dependence of intensity. The diffuse reflection component is dominant in the light reflected from the surface of the finger 52. On the other hand, the specular reflection component is dominant in the light reflected from the interface between the substrate 59 and the atmosphere.

[0051] The intensity of light reflected by the contact or non-contact surface between the finger 52 and the substrate 59 and incident on the layer 53 located directly below them is the sum of specularly reflected light and diffusely reflected light. As described above, at the concave portions of the finger 52, the substrate 59 and the finger 52 do not come into contact, so specularly reflected light (indicated by the solid arrows) is dominant, whereas at the convex portions, they come into contact, so diffusely reflected light (indicated by the dashed arrows) from the finger 52 is dominant. Therefore, the intensity of light received by the light receiving element in the layer 53 located directly below the concave portions is higher than the intensity of light received by the light receiving element in the layer 53 located directly below the convex portions. Therefore, the fingerprint of the finger 52 can be captured using the light receiving element.

[0052] The arrangement interval of the light receiving elements in layer 53 is set to be smaller than the distance between two convex portions of a fingerprint, preferably the distance between adjacent convex and concave portions, so that a clear fingerprint image can be obtained. Since the distance between convex and concave portions of a human fingerprint is generally between 150 μm and 250 μm, the arrangement interval of the light receiving elements is set to, for example, 400 μm or less, preferably 200 μm or less, more preferably 150 μm or less, even more preferably 120 μm or less, even more preferably 100 μm or less, and even more preferably 50 μm or less. The smaller the arrangement interval, the better, but it can be set to, for example, 1 μm or more, 10 μm or more, or 20 μm or more.

[0053] 1F shows an example of a fingerprint image captured by a display device according to one embodiment of the present invention. In FIG. 1F, the outline of finger 52 is indicated by a dashed line in region 65, and the outline of contact portion 69 is indicated by a dashed line. In region 65, a fingerprint 67 with high contrast can be captured due to differences in the amount of light incident on the light receiving element.

[0054] As described above, in the display device of one embodiment of the present invention, the light-receiving element can detect light that is emitted from the light-emitting element, irradiated onto an object such as the finger 52, and reflected by the object. Therefore, for example, even in a dark place, an object in contact with or close to the display portion can be detected, and authentication such as fingerprint authentication can be performed.

[0055] Furthermore, by providing the light receiving element in the display section, it is not necessary to attach a sensor externally to the display device, which reduces the number of components in the display device, thereby enabling the display device to be made smaller and lighter.

[0056] <Example of display device configuration> 2A shows a schematic cross-sectional view of the display device 10. The display device 10 has a light-emitting element 550R that emits red light, a light-emitting element 550G that emits green light, a light-emitting element 550B that emits blue light, and a light-receiving element 560.

[0057] The light-emitting element 550R has a configuration in which two light-emitting units 512R (light-emitting unit 512R_1 and light-emitting unit 512R_2) are stacked between a pair of electrodes (electrode 501R and electrode 502) with an intermediate layer 531R interposed therebetween. Similarly, the light-emitting element 550G has a configuration in which two light-emitting units 512G (light-emitting unit 512G_1 and light-emitting unit 512G_2) are stacked between a pair of electrodes (electrode 501G and electrode 502) with an intermediate layer 531G interposed therebetween. Furthermore, the light-emitting element 550B has a configuration in which two light-emitting units 512B (light-emitting unit 512B_1 and light-emitting unit 512B_2) are stacked between a pair of electrodes (electrode 501B and electrode 502) with an intermediate layer 531B interposed therebetween.

[0058] In the light receiving element 560, a light receiving unit 542 is provided between a pair of electrodes (electrode 501PD and electrode 502).

[0059] In this specification and the like, when describing matters common to the display device 10A and the display device 10B, or when there is no need to distinguish between them, the display device 10 will be simply referred to as "display device 10." In other words, the configuration of the display device 10 can be applied to both the display device 10A shown in FIG. 1A and the display device 10B shown in FIG. 1B. The same applies to other elements.

[0060] The electrode 501 functions as a pixel electrode and is provided for each light emitting element 550 and each light receiving element 560. The electrode 502 functions as a common electrode and is provided in common to a plurality of light emitting elements 550 and light receiving elements 560.

[0061] The light-emitting unit 512R_1 includes a layer 521, a layer 522, a light-emitting layer 523R, and a layer 524. The light-emitting unit 512R_2 includes a layer 522, a light-emitting layer 523R, and a layer 524. The light-emitting element 550R includes, for example, a layer 525R between the light-emitting unit 512R_2 and the electrode 502. The layer 525R can also be considered as part of the light-emitting unit 512R_2.

[0062] The layer 521 includes, for example, a layer containing a substance with a high hole-injecting property (hole-injecting layer). The layer 522 includes, for example, a layer containing a substance with a high hole-transporting property (hole-transporting layer). The layer 524 includes, for example, a layer containing a substance with a high electron-transporting property (electron-transporting layer). The layer 525 includes, for example, a layer containing a substance with a high electron-injecting property (electron-injecting layer).

[0063] Alternatively, a structure in which the layer 521 has an electron-injecting layer, the layer 522 has an electron-transporting layer, the layer 524 has a hole-transporting layer, and the layer 525 has a hole-injecting layer may be used.

[0064] The layer 522, the light-emitting layer 523R, and the layer 524 may have the same configuration (material, film thickness, etc.) between the light-emitting unit 512R_1 and the light-emitting unit 512R_2, or may have different configurations.

[0065] 2A, the layer 521 and the layer 522 are separately illustrated, but the present invention is not limited to this. For example, when the layer 521 has a function as both a hole injection layer and a hole transport layer, or when the layer 521 has a function as both an electron injection layer and an electron transport layer, the layer 522 may be omitted.

[0066] Furthermore, the intermediate layer 531R has a function of injecting electrons into one of the light-emitting unit 512R_1 and the light-emitting unit 512R_2 and injecting holes into the other when a voltage is applied between the electrode 501 and the electrode 502. The intermediate layer 531R can also be called a charge generation layer.

[0067] Although the above description has been made with respect to the light-emitting unit 512R, the same configuration can also be applied to the light-emitting unit 512G and the light-emitting unit 512B.

[0068] Note that light-emitting layer 523R included in light-emitting element 550R contains a light-emitting material that emits red light, light-emitting layer 523G included in light-emitting element 550G contains a light-emitting material that emits green light, and light-emitting layer 523B included in light-emitting element 550B contains a light-emitting material that emits blue light. Note that light-emitting element 550G and light-emitting element 550B have a configuration in which light-emitting layer 523R included in light-emitting element 550R is replaced with light-emitting layer 523G and light-emitting layer 523B, respectively, and the other configurations are similar to those of light-emitting element 550R.

[0069] The layers 521, 522, 524, and 525 may have the same configuration (material, film thickness, etc.) for the light-emitting elements of each color, or may have different configurations.

[0070] A configuration in which multiple light-emitting units are connected in series via an intermediate layer 531, such as light-emitting element 550R, light-emitting element 550G, and light-emitting element 550B, is referred to as a tandem structure in this specification. On the other hand, a configuration in which one light-emitting unit is located between a pair of electrodes is referred to as a single structure. Although the term "tandem structure" is used in this specification, the present invention is not limited to this, and the tandem structure may also be referred to as a stack structure, for example. The tandem structure allows for a light-emitting element capable of emitting light with high brightness. Furthermore, the tandem structure can reduce the current required to achieve the same brightness compared to a single structure, thereby improving the reliability of the display device.

[0071] Furthermore, a structure in which a different light-emitting layer is formed for each light-emitting element, such as light-emitting element 550R, light-emitting element 550G, and light-emitting element 550B, is sometimes called an SBS structure. The SBS structure allows the materials and configuration to be optimized for each light-emitting element, increasing the degree of freedom in selecting materials and configurations and making it easier to improve brightness and reliability.

[0072] The display device 10 according to one embodiment of the present invention can be said to have both a tandem structure and an SBS structure. Therefore, it can combine the advantages of both the tandem structure and the SBS structure. The display device 10 according to one embodiment of the present invention may also be referred to as a two-tier tandem structure because it has two tiers of light-emitting units formed in series, as shown in FIG. 2A . The two-tier tandem structure shown in FIG. 2A includes a first light-emitting unit having a red light-emitting layer and a second light-emitting unit having a red light-emitting layer stacked on top of the first light-emitting unit having a green light-emitting layer. Similarly, the two-tier tandem structure shown in FIG. 2A includes a first light-emitting unit having a green light-emitting layer and a second light-emitting unit having a blue light-emitting layer stacked on top of the first light-emitting unit having a blue light-emitting layer.

[0073] The light-receiving unit 542 of the light-receiving element 560 includes a layer 522, a light-receiving layer 543, and a layer 524. The light-receiving unit 542 may have a configuration without a hole injection layer and an electron injection layer. The layers 522 and 524 of the light-receiving unit 542 may have the same configurations (materials, film thickness, etc.) as the layers 522 and 524 of the light-emitting unit 512, or may have different configurations.

[0074] 2B is a modified example of the display device 10 shown in FIG. 2A. The display device 10 shown in FIG. 2B is an example in which the layer 525 is provided in common between the light-emitting elements 550 and between the light-receiving elements 560, similar to the electrode 502. In this case, the layer 525 can be called a common layer. By providing one or more common layers between the light-emitting elements 550 and between the light-receiving elements 560 in this way, the manufacturing process can be simplified, and therefore the manufacturing cost can be reduced.

[0075] Here, the layer 525 functions as an electron injection layer for the light-emitting element 550. On the other hand, it functions as an electron transport layer for the light-receiving element 560. Therefore, when the display device 10 has the configuration shown in FIG. 2B , the light-receiving unit 542 does not need to be provided with the layer 524 that functions as an electron transport layer.

[0076] The display device 10 shown in Fig. 3A is an example in which three light-emitting units are stacked. In Fig. 3A, the light-emitting element 550R has a light-emitting unit 512R_3 stacked on a light-emitting unit 512R_2 via an intermediate layer 531R. The light-emitting unit 512R_3 has the same configuration as the light-emitting unit 512R_2. The same applies to the light-emitting unit 512G_3 included in the light-emitting element 550G and the light-emitting unit 512B_3 included in the light-emitting element 550B.

[0077] FIG. 3B shows an example in which n light-emitting units (n is an integer of 2 or more) are stacked.

[0078] In this way, by increasing the number of stacked light-emitting units, the luminance obtained from the light-emitting element with the same amount of current can be increased in accordance with the number of stacked light-emitting units.Furthermore, by increasing the number of stacked light-emitting units, the current required to obtain the same luminance can be reduced, and therefore the power consumption of the light-emitting element can be reduced in accordance with the number of stacked light-emitting units.

[0079] FIG. 4 is a modified example of the display device 10 shown in FIG. 2A. The display device 10 shown in FIG. 4 is an example in which the light receiving element 560 has two light receiving units 542 (light receiving unit 542_1 and light receiving unit 542_2). The light receiving units 542_1 and 542_2 are stacked via an intermediate layer 531PD. Note that FIG. 4 illustrates a configuration in which two light receiving units are stacked, but the present invention is not limited to this. For example, a configuration in which three or more light receiving units are stacked may also be used.

[0080] The display device 10 shown in Figure 5A shows an example in which two adjacent light-emitting elements are spaced apart, and the electrodes 502 are provided along the side of the light-emitting unit 512, the side of the intermediate layer 531, and the side of the light-receiving unit 542, etc.

[0081] Here, if the intermediate layer 531 and the electrode 502 come into contact with each other, an electrical short circuit may occur. Therefore, it is preferable to insulate the intermediate layer 531 from the electrode 502.

[0082] 5A shows an example in which an insulating layer 541 is provided to cover the electrode 501, the side surfaces of each light-emitting unit 512, the side surfaces of the intermediate layer 531, and the side surfaces of the light-receiving unit 542. The insulating layer 541 can be called a sidewall protective layer, a sidewall insulating film, or the like. By providing the insulating layer 541, the intermediate layer 531 and the electrode 502 can be electrically insulated from each other.

[0083] Furthermore, it is preferable that the side surfaces of the light-emitting units 512, the intermediate layer 531, and the light-receiving units 542 are perpendicular or approximately perpendicular to the surface on which they are formed. For example, it is preferable that the angle formed between the surface on which they are formed and these side surfaces be 60 degrees or more and 90 degrees or less.

[0084] 5B shows an example in which the layer 525 and the electrode 502 are provided along the side surfaces of the light-emitting unit 512, the intermediate layer 531, and the light-receiving unit 542. Furthermore, a two-layer structure of insulating layers 541 and 544 is used as a sidewall protective layer.

[0085] FIG. 6A is a modified example of FIG. 5B. FIG. 6B is an enlarged view of region 503 shown in FIG. 6A. The shapes of the end portions of insulating layer 544 differ between FIG. 6A and FIG. 5B. Furthermore, because the shapes of the end portions of insulating layer 544 differ, and layer 525 and electrode 502 are formed along the shape of insulating layer 544, the shapes of layer 525 and electrode 502 also differ. The thicknesses of insulating layer 541 and insulating layer 544 differ between FIG. 6A and FIG. 5B. In FIG. 6A, insulating layer 544 is thicker than insulating layer 541. The end portions of insulating layer 544 have a rounded shape as shown in FIG. 6B. For example, when forming insulating layer 544, if dry etching is used to etch the upper portion of insulating layer 544 by anisotropic etching, the end portions of insulating layer 544 will have a rounded shape as shown in FIG. 6B. Rounding the end portion of the insulating layer 544 is preferable because it improves coverage of the layer 525 and the electrode 502. Furthermore, as shown in Figures 6A and 6B, making the thickness of the insulating layer 544 thicker than the thickness of the insulating layer 541 may make it easier to round the end portion.

[0086] The insulating layer 541 and the insulating layer 544, which function as sidewall protective layers, can prevent an electrical short circuit between the electrode 502 and the intermediate layer 531. Furthermore, the insulating layer 541 and the insulating layer 544 cover the side surfaces of the electrode 501, thereby preventing an electrical short circuit between the electrode 501 and the electrode 502. This can prevent an electrical short circuit at the four corners of the light-emitting element.

[0087] An inorganic insulating film is preferably used for each of the insulating layers 541 and 544. For example, an oxide or nitride film such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, aluminum oxide, aluminum oxynitride, or hafnium oxide can be used. Alternatively, yttrium oxide, zirconium oxide, gallium oxide, tantalum oxide, magnesium oxide, lanthanum oxide, cerium oxide, neodymium oxide, or the like can be used.

[0088] The insulating layers 541 and 544 can be formed by various film formation methods, such as sputtering, evaporation, chemical vapor deposition (CVD), and atomic layer deposition (ALD). In particular, the ALD method causes less film formation damage to the layer on which it is formed, so it is preferable to form the insulating layer 541, which is formed directly on the light-emitting unit and intermediate layer 531, by the ALD method. In this case, it is also preferable to form the insulating layer 544 by sputtering, as this can increase productivity.

[0089] For example, the insulating layer 541 can be an aluminum oxide film formed by an ALD method, and the insulating layer 544 can be a silicon nitride film formed by a sputtering method.

[0090] Either or both of the insulating layer 541 and the insulating layer 544 preferably have a function as a barrier insulating film against at least one of water and oxygen. Alternatively, either or both of the insulating layer 541 and the insulating layer 544 preferably have a function of suppressing diffusion of at least one of water and oxygen. Alternatively, either or both of the insulating layer 541 and the insulating layer 544 preferably have a function of capturing or fixing (also referred to as gettering) at least one of water and oxygen.

[0091] In this specification and the like, a barrier insulating film refers to an insulating film having barrier properties. In addition, in this specification and the like, the barrier properties refer to a function of suppressing the diffusion of a corresponding substance (also referred to as low permeability) or a function of capturing or fixing (also referred to as gettering) a corresponding substance.

[0092] When either or both of the insulating layer 541 and the insulating layer 544 have the above-described function of a barrier insulating film or a gettering function, the insulating layer 541 and the insulating layer 544 can suppress the intrusion of impurities (typically, water or oxygen) that may diffuse into each light-emitting element from the outside. With this structure, a highly reliable display device can be provided.

[0093] 6C, the display device 10 may be configured without the insulating layers 541 and 544 that function as sidewall protective layers. In FIG. 6C, the layer 525 is provided in contact with the side surfaces of the light-emitting units 512, the intermediate layer 531, and the light-receiving unit 542.

[0094] <Configuration example of light-emitting element> The emission color of each light-emitting element can be red, green, blue, cyan, magenta, yellow, white, or the like, depending on the material constituting the light-emitting layer 523, etc. Furthermore, by providing the light-emitting element with a microcavity structure, the color purity can be further improved.

[0095] In order to obtain a light-emitting element that emits white light, it is preferable to configure the light-emitting layer to contain two or more types of light-emitting materials. To obtain white light emission, it is sufficient to select light-emitting materials such that the light emitted from each of the two or more light-emitting materials has a complementary color relationship. For example, by making the light-emitting color of the first light-emitting layer and the light-emitting color of the second light-emitting layer complementary, a light-emitting element that emits white light as a whole can be obtained. The same applies to a light-emitting element having three or more light-emitting layers.

[0096] The light-emitting layer preferably contains two or more light-emitting materials that emit light of R (red), G (green), B (blue), Y (yellow), O (orange), or the like.

[0097] Here, specific examples of each layer of the light emitting element will be described.

[0098] The light-emitting element has at least a light-emitting layer. The light-emitting element may further have, as a layer other than the light-emitting layer, a layer containing a substance with high hole-injection properties, a substance with high hole-transport properties, a hole-blocking material, a substance with high electron-transport properties, an electron-blocking material, a substance with high electron-injection properties, a bipolar substance (a substance with high electron-transport properties and high hole-transport properties), or the like.

[0099] The light-emitting element can be made of either a low-molecular-weight compound or a high-molecular-weight compound, and may contain an inorganic compound. Each of the layers constituting the light-emitting element can be formed by a method such as vapor deposition (including vacuum vapor deposition), a transfer method, a printing method, an inkjet method, or a coating method.

[0100] For example, the light-emitting element can have one or more layers selected from the group consisting of a hole injection layer, a hole transport layer, a hole blocking layer, an electron blocking layer, an electron transport layer, and an electron injection layer.

[0101] The hole injection layer is a layer that injects holes from the anode into the hole transport layer and contains a material with high hole injection properties, such as an aromatic amine compound and a composite material containing a hole transport material and an acceptor material (electron acceptor material).

[0102] The hole transport layer is a layer that transports holes injected from the anode by the hole injection layer to the light emitting layer. The hole transport layer is a layer that contains a hole transport material. The hole transport material is a material having a concentration of 1×10 -6 cm 2 A material having a hole mobility of 1 / Vs or more is preferred. Note that other materials can also be used as long as they have a higher hole transporting property than electron transporting property. As the hole transporting material, a material having a high hole transporting property, such as a π-electron-rich heteroaromatic compound (e.g., a carbazole derivative, a thiophene derivative, or a furan derivative), or an aromatic amine (a compound having an aromatic amine skeleton), is preferred.

[0103] The electron transport layer is a layer that transports electrons injected from the cathode by the electron injection layer to the light emitting layer. The electron transport layer is a layer that contains an electron transporting material. The electron transporting material is a material having a molecular weight of 1×10 -6 cm 2 A substance having an electron mobility of 1 / Vs or more is preferred. Note that other substances can also be used as long as they have a higher electron transporting property than holes. Examples of electron-transporting materials that can be used include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, and metal complexes having a thiazole skeleton, as well as oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives having a quinoline ligand, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, and other π-electron-deficient heteroaromatic compounds including nitrogen-containing heteroaromatic compounds.

[0104] The electron injection layer is a layer that injects electrons from the cathode to the electron transport layer and contains a material with high electron injection properties. Examples of the material with high electron injection properties include alkali metals, alkaline earth metals, and compounds thereof. Examples of the material with high electron injection properties include a composite material containing an electron transport material and a donor material (electron donor material).

[0105] The electron injection layer may be formed of, for example, lithium, cesium, ytterbium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF X , where X is an arbitrary number), 8-(quinolinolato)lithium (abbreviation: Liq), 2-(2-pyridyl)phenolatolithium (abbreviation: LiPP), 2-(2-pyridyl)-3-pyridinolatolithium (abbreviation: LiPPy), 4-phenyl-2-(2-pyridyl)phenolatolithium (abbreviation: LiPPP), lithium oxide (LiO x), or alkali metals such as cesium carbonate, alkaline earth metals, or compounds thereof can be used. The electron injection layer may have a stacked structure of two or more layers. For example, the stacked structure may have a structure in which lithium fluoride is used in the first layer and ytterbium is used in the second layer.

[0106] Alternatively, the electron injection layer may be formed using a material having electron transport properties. For example, a compound having an unshared electron pair and an electron-deficient heteroaromatic ring may be used as the material having electron transport properties. Specifically, a compound having at least one of a pyridine ring, a diazine ring (pyrimidine ring, pyrazine ring, pyridazine ring), and a triazine ring may be used.

[0107] The organic compound having an unshared electron pair preferably has a lowest unoccupied molecular orbital (LUMO) of -3.6 eV to -2.3 eV. Generally, the highest occupied molecular orbital (HOMO) level and the LUMO level of an organic compound can be estimated by cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, or the like.

[0108] Examples of organic compounds with lone electron pairs include 4,7-diphenyl-1,10-phenanthroline (abbreviated as BPhen), 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen), diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviated as HATNA), and 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviated as TmPPPyTz). NBPhen has a higher glass transition temperature (Tg) and better heat resistance than BPhen.

[0109] The light-emitting layer is a layer containing a light-emitting substance. The light-emitting layer can contain one or more light-emitting substances. As the light-emitting substance, a substance that emits light of blue, purple, blue-purple, green, yellow-green, yellow, orange, red, or the like is appropriately used. Furthermore, a substance that emits near-infrared light can also be used as the light-emitting substance.

[0110] Examples of the light-emitting material include fluorescent materials, phosphorescent materials, TADF materials, and quantum dot materials.

[0111] Examples of fluorescent materials include pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives.

[0112] Examples of phosphorescent materials include organometallic complexes (particularly iridium complexes) having a 4H-triazole skeleton, a 1H-triazole skeleton, an imidazole skeleton, a pyrimidine skeleton, a pyrazine skeleton, or a pyridine skeleton; organometallic complexes (particularly iridium complexes) having a phenylpyridine derivative having an electron-withdrawing group as a ligand; platinum complexes; and rare earth metal complexes.

[0113] The light-emitting layer may contain one or more organic compounds (host materials, assist materials, etc.) in addition to a light-emitting substance (guest material). One or more organic compounds may be a hole-transporting material or an electron-transporting material, or both. Alternatively, a bipolar material or a TADF material may be used as the one or more organic compounds.

[0114] The light-emitting layer preferably contains, for example, a phosphorescent material and a hole-transporting material and an electron-transporting material that are a combination that easily forms an exciplex. This configuration allows for efficient emission using Exciplex-Triplet Energy Transfer (ExTET), which is energy transfer from the exciplex to the light-emitting material (phosphorescent material). By selecting a combination that forms an exciplex that emits light that overlaps with the wavelength of the lowest-energy absorption band of the light-emitting material, the energy transfer becomes smooth, allowing for efficient emission. This configuration simultaneously enables high efficiency, low-voltage operation, and long life of the light-emitting element.

[0115] For example, a material applicable to an electron injection layer, such as lithium, can be suitably used for the intermediate layer. For example, a material applicable to a hole injection layer can be suitably used for the intermediate layer. For example, a layer containing a hole transport material and an acceptor material (electron acceptor material) can be used for the intermediate layer. For example, a layer containing an electron transport material and a donor material can be used for the intermediate layer. By forming an intermediate layer having such a layer, an increase in driving voltage can be suppressed when light-emitting units are stacked.

[0116] 2A, the light-emitting material of the light-emitting layer is not particularly limited. For example, in the display device 10 shown in FIG. 2A, the light-emitting layer 523R of the light-emitting unit 512R_1 may contain a phosphorescent material, the light-emitting layer 523R of the light-emitting unit 512R_2 may contain a phosphorescent material, the light-emitting layer 523G of the light-emitting unit 512G_1 may contain a fluorescent material, the light-emitting layer 523G of the light-emitting unit 512G_2 may contain a fluorescent material, the light-emitting layer 523B of the light-emitting unit 512B_1 may contain a fluorescent material, and the light-emitting layer 523B of the light-emitting unit 512B_2 may contain a fluorescent material.

[0117] Alternatively, in the display device 10 shown in FIG. 2A, the light-emitting layer 523R of the light-emitting unit 512R_1 may contain a phosphorescent material, the light-emitting layer 523R of the light-emitting unit 512R_2 may contain a phosphorescent material, the light-emitting layer 523G of the light-emitting unit 512G_1 may contain a phosphorescent material, the light-emitting layer 523G of the light-emitting unit 512G_2 may contain a phosphorescent material, the light-emitting layer 523B of the light-emitting unit 512B_1 may contain a fluorescent material, and the light-emitting layer 523B of the light-emitting unit 512B_2 may contain a fluorescent material.

[0118] Note that the display device of one embodiment of the present invention may have a structure in which all the light-emitting layers of the display device 10 shown in FIG. 2A are formed using a fluorescent material, or a structure in which all the light-emitting layers of the display device 10 shown in FIG. 2A are formed using a phosphorescent material.

[0119] 2A , the display device of one embodiment of the present invention may have a structure in which the light-emitting layer 523R of the light-emitting unit 512R_1 is made of a phosphorescent material and the light-emitting layer 523R of the light-emitting unit 512R_2 is made of a fluorescent material, or the light-emitting layer 523R of the light-emitting unit 512R_1 is made of a fluorescent material and the light-emitting layer 523R of the light-emitting unit 512R_2 is made of a phosphorescent material, that is, a structure in which the light-emitting material used for the first light-emitting layer is different from a structure in which the light-emitting material used for the second light-emitting layer is different. Note that although the light-emitting units 512R_1 and 512R_2 are specifically described here, similar structures can also be applied to the light-emitting units 512G_1 and 512G_2 and the light-emitting units 512B_1 and 512B_2.

[0120] <Configuration example of a photodetector> The light-receiving layer 543 of the light-receiving element 560 includes a semiconductor. Examples of the semiconductor include inorganic semiconductors such as silicon and organic semiconductors containing organic compounds. In this embodiment, an example is shown in which an organic semiconductor is used as the semiconductor of the light-receiving layer 543. By using an organic semiconductor, the light-emitting layer 523 and the light-receiving layer 543 can be formed by the same method (for example, vacuum deposition), which is preferable because a common manufacturing device can be used.

[0121] The n-type semiconductor material of the light-receiving layer 543 is fullerene (e.g., C 60 or C 70 Examples of suitable materials include electron-accepting organic semiconductor materials such as fullerene derivatives, or fullerene derivatives. Fullerenes have a soccer ball-like shape, which is energetically stable. Fullerenes have deep (low) HOMO and LUMO levels. Because fullerenes have a deep LUMO level, they have extremely high electron-accepting (acceptor) properties. Normally, when the π-electron conjugation (resonance) spreads on a plane, as in benzene, the electron-donating (donor) properties increase, but fullerenes have a spherical shape, so they have high electron-accepting properties despite the large spread of π-electrons. High electron-accepting properties allow charge separation to occur quickly and efficiently, making them useful as light-receiving elements. C 60 , and C 70 Both have a wide absorption band in the visible light region, especially C 70 is C 60 It is preferable because it has a larger π-electron conjugated system and a broad absorption band in the long wavelength region compared to [6,6]-Phenyl-C71-butyric acid methyl ester (abbreviation: PC70BM), [6,6]-Phenyl-C61-butyric acid methyl ester (abbreviation: PC60BM), and 1',1'',4',4''-Tetrahydro-di[1,4]methanonaphthaleno[1,2:2',3',56,60:2'',3''][5,6]fullerene-C60 (abbreviation: ICBA).

[0122] Examples of n-type semiconductor materials include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, naphthalene derivatives, anthracene derivatives, coumarin derivatives, rhodamine derivatives, triazine derivatives, and quinone derivatives.

[0123] Examples of the p-type semiconductor material of the light-receiving layer 543 include electron-donating organic semiconductor materials such as copper(II) phthalocyanine (CuPc), tetraphenyldibenzoperiflanthene (DBP), zinc phthalocyanine (ZnPc), tin phthalocyanine (SnPc), and quinacridone.

[0124] Examples of p-type semiconductor materials include carbazole derivatives, thiophene derivatives, furan derivatives, and compounds having an aromatic amine skeleton. Examples of p-type semiconductor materials include naphthalene derivatives, anthracene derivatives, pyrene derivatives, triphenylene derivatives, fluorene derivatives, pyrrole derivatives, benzofuran derivatives, benzothiophene derivatives, indole derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, indolocarbazole derivatives, porphyrin derivatives, phthalocyanine derivatives, naphthalocyanine derivatives, quinacridone derivatives, polyphenylenevinylene derivatives, polyparaphenylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, and polythiophene derivatives.

[0125] The HOMO level of the electron-donating organic semiconductor material is preferably shallower (higher) than the HOMO level of the electron-accepting organic semiconductor material, and the LUMO level of the electron-donating organic semiconductor material is preferably shallower (higher) than the LUMO level of the electron-accepting organic semiconductor material.

[0126] It is preferable to use a spherical fullerene as the electron-accepting organic semiconductor material and a planar organic semiconductor material as the electron-donating organic semiconductor material. Molecules with similar shapes tend to aggregate together, and when molecules of the same type aggregate, the energy levels of their molecular orbitals become close, which can improve carrier transport properties.

[0127] For example, the light-receiving layer 543 is preferably formed by co-evaporating an n-type semiconductor and a p-type semiconductor, or may be formed by laminating an n-type semiconductor and a p-type semiconductor.

[0128] <Example of the top surface configuration of the display device> 7A is a schematic top view showing an example of the configuration of display device 10. Display device 10 has a plurality of light-emitting elements 550R that emit red light, a plurality of light-emitting elements 550G that emit green light, a plurality of light-emitting elements 550B that emit blue light, and a plurality of light-receiving elements 560. In FIG. 7A, to easily distinguish between the light-emitting elements 550, the light-emitting regions of each light-emitting element 550 are labeled with R, G, and B. Furthermore, the light-receiving regions of each light-receiving element 560 are labeled with PD.

[0129] The light-emitting elements 550R, 550G, 550B, and the light-receiving elements 560 are arranged in a matrix. FIG. 7A shows an example in which the light-emitting elements 550R, 550G, and 550B are arranged in the X direction, and the light-receiving elements 560 are arranged below them. FIG. 7A also shows an example in which the light-emitting elements 550 emitting light of the same color are arranged in the Y direction intersecting the X direction. In the display device 10 shown in FIG. 7A, a pixel 20 can be configured by, for example, a sub-pixel having the light-emitting element 550R, a sub-pixel having the light-emitting element 550G, and a sub-pixel having the light-emitting element 550B arranged in the X direction, and a sub-pixel having the light-receiving element 560 provided below these sub-pixels.

[0130] 7A shows a connection electrode 501C. The connection electrode 501C is provided outside the display section where the light emitting elements 550 and the light receiving elements 560 are arranged.

[0131] The connection electrode 501C can be provided along the periphery of the display unit. For example, it may be provided along one side of the periphery of the display unit, or it may be provided over two or more sides of the periphery of the display unit. That is, when the top surface of the display unit has a rectangular shape, the top surface of the connection electrode 501C can have a strip shape, an L-shape, a U-shape (square bracket shape), a frame shape, or the like.

[0132] Fig. 7B is a schematic top view showing an example of the configuration of display device 10, which is a modification of display device 10 shown in Fig. 7A. Display device 10 shown in Fig. 7B differs from display device 10 shown in Fig. 7A in that it includes light-emitting element 550IR that emits infrared light. Light-emitting element 550IR can emit, for example, near-infrared light (light with a wavelength of 750 nm or more and 1300 nm or less).

[0133] 7B, in addition to light-emitting elements 550R, 550G, and 550B, light-emitting element 550IR is arranged in the X direction, and light-receiving element 560 is arranged below light-emitting elements 550R, 550G, and 550B. Light-receiving element 560 has the function of detecting infrared light.

[0134] Fig. 8A is a schematic top view showing an example of the configuration of display device 10, which is a modification of display device 10 shown in Fig. 7B. Display device 10 shown in Fig. 8A differs from display device 10 shown in Fig. 7B in that light receiving elements 560 and light emitting elements 550IR are arranged alternately in the X direction.

[0135] 8A, the light-emitting elements 550R, 550G, and 550B are arranged in different rows from the light-emitting element 550IR. This allows the widths (lengths in the X direction) of the light-emitting elements 550R, 550G, and 550B to be increased, thereby increasing the brightness of the light emitted by the pixel 20.

[0136] Fig. 8B is a schematic top view showing an example of the configuration of the display device 10, which is a modification of the display device 10 shown in Fig. 8A. The display device 10 shown in Fig. 8B differs from the display device 10 shown in Fig. 8A in that the light-emitting elements 550 are arranged in the order G, B, R rather than R, G, B in the X direction. The display device 10 also differs from the display device 10 shown in Fig. 8A in that the light-receiving element 560 is provided below the light-emitting elements 550G and 550B, and the light-emitting element 550IR is provided below the light-emitting element 550R.

[0137] The area occupied by the light receiving element 560 in the display device 10 shown in FIG. 8B is larger than the area occupied by the light receiving element 560 in the display device 10 shown in FIG. 8A. This increases the sensitivity of light detection by the light receiving element 560. Therefore, for example, when the display device 10 functions as a touch sensor or a near-touch sensor, it is possible to detect an object in contact with or in proximity to the display device 10 with high accuracy. In particular, when the display device 10 functions as a near-touch sensor, the sensitivity of light detection by the light receiving element 560 has a significant effect on the accuracy of object detection, so it is preferable to increase the area occupied by the light receiving element 560.

[0138] Fig. 9A is a schematic top view showing an example of the configuration of the display device 10, which is a modified example of the display device 10 shown in Fig. 8B. The display device 10 shown in Fig. 9A differs from the display device 10 shown in Fig. 8B in that the light receiving element 560 is provided below the light emitting element 550G, and the light emitting element 550IR is provided below the light emitting elements 550B and 550R.

[0139] The area occupied by the light receiving elements 560 in the display device 10 shown in FIG. 9A is smaller than the area occupied by the light receiving elements 560 in the display device 10 shown in FIG. 8B. By narrowing the area occupied by the light receiving elements 560, the light receiving range of each light receiving element 560 can be narrowed. This reduces the overlap of the light receiving ranges between different light receiving elements 560, for example, between adjacent light receiving elements 560. This prevents the image captured using the light receiving elements 560 from becoming blurred, making it difficult to capture a clear image. For the above reasons, if the display device 10 has a function for performing authentication such as fingerprint authentication, for example, reducing the area occupied by the light receiving elements 560 is preferable because it allows, for example, a fingerprint to be clearly captured and increases the accuracy of authentication.

[0140] 9B is a cross-sectional view showing the change in the light-receiving range of light-receiving element 560 when the occupation area of ​​light-receiving element 560, specifically the length in the X direction, is changed. In FIG. 9B, light-receiving element 560 is shown on the lower surface side of layer 71, and light-shielding layer 73 is shown on the upper surface side of layer 71. Substrate 59 is also shown on layer 71. Furthermore, a light-receiving element whose length in the X direction is approximately three times that of light-receiving element 560 is designated as light-receiving element 560L.

[0141] 9B, light incident on light receiving element 560 is designated as light 75 and is indicated by a solid line. Light that is not incident on light receiving element 560 but is incident on light receiving element 560L is designated as light 77 and is indicated by a dashed line. The light receiving range of each light receiving element 560 is designated as light receiving range 80, and the light receiving range of each light receiving element 560L is designated as light receiving range 81.

[0142] As shown in Fig. 9B, the light-receiving range 80 of the light-receiving element 560 is narrower than the light-receiving range 81 of the light-receiving element 560L. In other words, as the area occupied by the light-receiving element becomes smaller, the light-receiving range per light-receiving element becomes narrower, and the overlap of the light-receiving ranges between different light-receiving elements becomes smaller. Fig. 9B shows an example in which the light-receiving ranges 80 of adjacent light-receiving elements 560 on the surface of the substrate 59 do not overlap, but the light-receiving ranges 81 of adjacent light-receiving elements 560L partially overlap.

[0143] Fig. 10 is a schematic top view showing an example of the configuration of the display device 10, which is a modified example of the display device 10 shown in Fig. 7A. The display device 10 shown in Fig. 10 differs from the display device 10 shown in Fig. 7A in that light receiving elements 560 are provided only in some of the pixels 20.

[0144] 10 , the drive frequency of the display device 10 can be increased. Therefore, for example, if the display device 10 functions as a touch sensor or a near-touch sensor, the position of an object in contact with or near the display device 10 can be quickly detected. Therefore, for example, the movement of an object in contact with or near the display device 10 can be detected quickly and accurately.

[0145] <Example of cross-sectional configuration of display device> Fig. 11A is a cross-sectional view corresponding to dashed dotted line A1-A2 in Fig. 7A, and Fig. 11B is a cross-sectional view corresponding to dashed dotted line B1-B2 in Fig. 7A. Fig. 11C is a cross-sectional view corresponding to dashed dotted line C1-C2 in Fig. 7A, and Fig. 11D is a cross-sectional view corresponding to dashed dotted line D1-D2 in Fig. 7A. Fig. 11E is a cross-sectional view corresponding to dashed dotted line B3-B4 in Fig. 8A. Figs. 11A to 11E show a configuration example corresponding to Fig. 2A.

[0146] The light emitting element 550R, the light emitting element 550G, the light emitting element 550B, and the light receiving element 560 are provided on the substrate 101. When the display device 10 includes the light emitting element 550IR, the light emitting element 550IR is provided on the substrate 101.

[0147] In this specification and the like, for example, when it is said that "B is on A" or "B is below A," A and B do not necessarily have to have an area where they contact each other.

[0148] 11A shows an example of the cross-sectional configuration of light-emitting element 550R, light-emitting element 550G, and light-emitting element 550B. Also, FIG.

[0149] As described above, the light-emitting element 550R includes an electrode 501R, a light-emitting unit 512R_1, an intermediate layer 531R, a light-emitting unit 512R_2, a layer 525R, and an electrode 502. The light-emitting element 550G includes an electrode 501G, a light-emitting unit 512G_1, an intermediate layer 531G, a light-emitting unit 512G_2, a layer 525G, and an electrode 502. The light-emitting element 550B includes an electrode 501B, a light-emitting unit 512B_1, an intermediate layer 531B, a light-emitting unit 512B_2, a layer 525B, and an electrode 502. The light-receiving element 560 includes an electrode 501PD, a light-receiving unit 542, and an electrode 502.

[0150] A gap is provided between the electrode 502 and the insulating layer 131. This prevents the electrode 502 from coming into contact with the side surfaces of the light-emitting unit 512 and the light-receiving unit 542. This prevents a short circuit in the light-emitting element 550 and a short circuit in the light-receiving element 560.

[0151] The gap is more easily formed, for example, as the distance between the light-emitting units 512 becomes shorter. For example, the gap can be suitably formed by setting the distance to 1 μm or less, preferably 500 nm or less, and more preferably 200 nm or less, 100 nm or less, 90 nm or less, 70 nm or less, 50 nm or less, 30 nm or less, 20 nm or less, 15 nm or less, or 10 nm or less.

[0152] An insulating layer 131 is provided to cover the end of electrode 501R, the end of electrode 501G, the end of electrode 501B, and the end of electrode 501PD. The end of insulating layer 131 is preferably tapered. Note that insulating layer 131 does not have to be provided if it is not necessary.

[0153] For example, the light-emitting unit 512R_1, the light-emitting unit 512G_1, the light-emitting unit 512B_1, and the light-receiving unit 542 each have a region in contact with the upper surface of the electrode 501 and a region in contact with the surface of the insulating layer 131. Furthermore, an end of the light-emitting unit 512R_1, an end of the light-emitting unit 512G_1, an end of the light-emitting unit 512B_1, and an end of the light-receiving unit 542 are located on the insulating layer 131.

[0154] As shown in FIG. 11A , a gap is provided between, for example, two light-emitting units 512 between light-emitting elements 550 that emit light of different colors. In this manner, for example, light-emitting unit 512R_1, light-emitting unit 512G_1, and light-emitting unit 512B_1 are preferably arranged so as not to contact one another. Furthermore, for example, light-emitting unit 512R_2, light-emitting unit 512G_2, and light-emitting unit 512B_2 are preferably arranged so as not to contact one another. This effectively prevents current from flowing through two adjacent light-emitting units 512, which would otherwise cause unintended light emission. This improves the contrast of the display device 10, thereby improving the display quality of the display device 10.

[0155] A protective layer 125 is provided over the electrode 502. The protective layer 125 has a function of preventing impurities such as water from diffusing into the light-emitting element 550 and the light-receiving element 560 from above.

[0156] The protective layer 125 may have, for example, a single-layer structure or a stacked-layer structure including at least an inorganic insulating film. Examples of the inorganic insulating film include oxide films and nitride films such as a silicon oxide film, a silicon oxynitride film, a silicon nitride oxide film, a silicon nitride film, an aluminum oxide film, an aluminum oxynitride film, and a hafnium oxide film. Alternatively, the protective layer 125 may be made of a semiconductor material such as indium gallium oxide or indium gallium zinc oxide.

[0157] In this specification and the like, a silicon oxynitride film refers to a film whose composition contains more oxygen than nitrogen, and a silicon nitride oxide film refers to a film whose composition contains more nitrogen than oxygen.

[0158] Alternatively, the protective layer 125 may be a laminated film of an inorganic insulating film and an organic insulating film. For example, a configuration in which an organic insulating film is sandwiched between a pair of inorganic insulating films is preferable. Furthermore, it is preferable that the organic insulating film functions as a planarizing film. This allows the upper surface of the organic insulating film to be flat, improving the coverage of the inorganic insulating film thereon and enhancing the barrier properties. Furthermore, since the upper surface of the protective layer 125 is flat, when a structure (e.g., a color filter, a touch sensor electrode, a lens array, or the like) is provided above the protective layer 125, the influence of uneven shapes caused by the structure below can be reduced, which is preferable.

[0159] 11C shows an example of a cross-sectional configuration of display device 10 in the Y direction, specifically showing an example of a cross-sectional configuration of light-emitting element 550R and light-receiving element 560. Note that light-emitting element 550G and light-emitting element 550B can also be arranged in the Y direction, similar to light-emitting element 550R.

[0160] 11D shows connection portion 130 where connection electrode 501C and electrode 502 are electrically connected. In connection portion 130, electrode 502 is provided in contact with connection electrode 501C, and protective layer 125 is provided to cover electrode 502. In addition, insulating layer 131 is provided to cover the end of connection electrode 501C.

[0161] 11E shows an example of the cross-sectional configuration of a light-emitting element 550IR, as well as an example of the cross-sectional configuration of the light-receiving element 560. The light-emitting element 550IR has an electrode 501IR, a light-emitting unit 512IR_1, an intermediate layer 531IR, a light-emitting unit 512IR_2, a layer 525IR, and an electrode 502.

[0162] The light-emitting unit 512IR_1 and the light-emitting unit 512IR_2 of the light-emitting element 550IR include a light-emitting organic compound that emits light having an intensity in at least the wavelength range of infrared light. For example, the light-emitting unit 512IR_1 and the light-emitting unit 512IR_2 include a light-emitting organic compound that emits light having an intensity in the wavelength range of near-infrared light. When the display device 10 includes the light-emitting element 550IR, the light-receiving unit 542 of the light-receiving element 560 includes an organic compound that has detection sensitivity in the wavelength range of infrared light, for example, near-infrared light.

[0163] <Example of a method for manufacturing a display device> An example of a manufacturing method of a display device according to one embodiment of the present invention will be described below with reference to the drawings. Here, the manufacturing method of the display device 10 shown in FIG. 7A and FIGS. 11A to 11D will be described as an example. FIGS. 12A to 15C are schematic cross-sectional views illustrating steps in the manufacturing method of the display device, which will be described below. FIGS. 12A to 15C show cross sections corresponding to dashed lines A1-A2, B1-B2, and D1-D2 in FIG. 7A.

[0164] The thin films (insulating films, semiconductor films, conductive films, etc.) that make up the display device can be formed using a sputtering method, a CVD method, a vacuum evaporation method, a pulsed laser deposition (PLD) method, an ALD method, etc. CVD methods include a plasma enhanced chemical vapor deposition (PECVD) method and a thermal CVD method. Another thermal CVD method is a metal organic chemical vapor deposition (MOCVD) method.

[0165] Furthermore, thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed by methods such as spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, or knife coating.

[0166] Furthermore, when processing the thin film that constitutes the display device, for example, a photolithography method can be used, but the thin film may also be processed by a nanoimprint method, a sandblasting method, a lift-off method, or the like.

[0167] There are two typical photolithography methods: one is to form a resist mask on the thin film to be processed, process the thin film by etching, and then remove the resist mask; the other is to form a photosensitive thin film, and then process the thin film into the desired shape by exposure and development.

[0168] In photolithography, the light used for exposure may be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture of these. Other light sources that can be used include ultraviolet light, KrF laser light, and ArF laser light. Exposure may also be performed by immersion exposure technology. Extreme ultraviolet (EUV) light, X-rays, or the like may also be used for exposure. An electron beam may also be used instead of light for exposure. Extreme ultraviolet light, X-rays, or an electron beam are preferred because they enable extremely fine processing. When exposure is performed by scanning a beam such as an electron beam, a photomask is not required.

[0169] The thin film can be etched by dry etching, wet etching, sandblasting, or the like.

[0170] To fabricate the display device 10, first, a substrate 101 is prepared. The substrate 101 may be a substrate having heat resistance sufficient to withstand at least a subsequent heat treatment. When an insulating substrate is used as the substrate 101, a glass substrate, a quartz substrate, a sapphire substrate, a ceramic substrate, an organic resin substrate, or the like may be used. Alternatively, a semiconductor substrate such as a single crystal semiconductor substrate made of silicon or silicon carbide, a polycrystalline semiconductor substrate, a compound semiconductor substrate such as silicon germanium, or an SOI substrate may be used.

[0171] Next, the electrodes 501R, 501G, 501B, 501PD, and the connection electrode 501C are formed on the substrate 101. First, a conductive film is formed, a resist mask is formed by photolithography, and unnecessary portions of the conductive film are removed by etching. After that, the resist mask is removed, thereby forming the electrodes 501R, 501G, and 501B.

[0172] When a conductive film reflective to visible light is used as the conductive film, it is preferable to use a material (such as silver or aluminum) having as high a reflectance as possible over the entire wavelength range of visible light, which not only increases the light extraction efficiency of the light-emitting element but also improves color reproducibility.

[0173] Subsequently, an insulating layer 131 is formed to cover the ends of the electrodes 501R, 501G, 501B, and 501PD (FIG. 12A). An organic insulating film or an inorganic insulating film can be used as the insulating layer 131. The insulating layer 131 preferably has tapered ends to improve step coverage of subsequent films. In particular, when an organic insulating film is used, it is preferable to use a photosensitive material, as this makes it easier to control the shape of the ends by adjusting the exposure and development conditions. Note that an inorganic insulating film may also be used as the insulating layer 131. By using an inorganic insulating film as the insulating layer 131, the display device 10 can be a high-definition display device.

[0174] Next, a layer 512Rf_1, which will later become the light-emitting unit 512R_1, is formed on the electrode 501R, the electrode 501G, the electrode 501B, the electrode 501PD, and the insulating layer 131. Specifically, a film, which will later become the layer 521, a film, which will later become the layer 522, a light-emitting film, which will later become the light-emitting layer 523R, and a film, which will later become the layer 524, are formed in this order. Then, an intermediate film 531Rf, which will later become the intermediate layer 531R, is formed on the layer 512Rf_1.

[0175] Subsequently, a layer 512Rf_2, which will later become the light-emitting unit 512R_2, is formed on the intermediate film 531Rf. Specifically, a film, which will later become the layer 522, a light-emitting film, which will later become the light-emitting layer 523R, and a film, which will later become the layer 524, are formed in this order. Thereafter, a film 525Rf, which will later become the layer 525R, is formed on the layer 512Rf_2.

[0176] The film of the layer 512Rf_1, the intermediate film 531Rf, the film of the layer 512Rf_2, and the film 525Rf can be formed by, for example, a vapor deposition method, a sputtering method, an inkjet method, etc. However, the present invention is not limited to this, and the above-mentioned film formation methods can be used as appropriate.

[0177] The layer 512Rf_1, the intermediate film 531Rf, the layer 512Rf_2, and the film 525Rf are preferably formed so as not to be provided on the connection electrode 501C. For example, when the film included in the layer 512Rf_1, the intermediate film 531Rf, the film included in the layer 512Rf_2, and the film 525Rf are formed by vapor deposition or sputtering, it is preferable to form them using a shielding mask so that the film included in the layer 512Rf_1, the intermediate film 531Rf, the film included in the layer 512Rf_2, and the film 525Rf are not formed on the connection electrode 501C.

[0178] Subsequently, the sacrificial film 141a is formed on the film 525Rf. The sacrificial film 141a can be provided in contact with the upper surface of the connection electrode 501C.

[0179] The sacrificial film 141a can be a film that is highly resistant to etching of the film 525Rf, the film included in the layer 512Rf_2, the intermediate film 531Rf, and the film included in the layer 512Rf_1, i.e., a film with a large etching selectivity. The sacrificial film 141a can also be a film that has a large etching selectivity with respect to a protective film such as a protective film 143a (described later). The sacrificial film 141a can also be a film that can be removed by wet etching, which causes little damage to the film 525Rf, the film included in the layer 512Rf_2, the intermediate film 531Rf, and the film included in the layer 512Rf_1.

[0180] The sacrificial film 141a may be, for example, a metal film, an alloy film, a metal oxide film, a semiconductor film, or an inorganic film such as an inorganic insulating film. The sacrificial film 141a may be formed by various film formation methods such as a sputtering method, a vapor deposition method, a CVD method, or an ALD method.

[0181] The sacrificial film 141a may be made of a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, or tantalum, or an alloy material containing such a metal material. In particular, it is preferable to use a low-melting-point material such as aluminum or silver.

[0182] The sacrificial film 141a may be made of a metal oxide such as indium gallium zinc oxide (In-Ga-Zn oxide, also referred to as IGZO). Other examples include indium oxide, indium zinc oxide (In-Zn oxide), indium tin oxide (In-Sn oxide), indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), and indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide). Alternatively, silicon-containing indium tin oxide may be used.

[0183] The present invention can also be applied to a case where an element M (wherein M is one or more elements selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium) is used instead of the above-mentioned gallium.

[0184] The sacrificial film 141a may be made of an inorganic insulating material such as aluminum oxide, hafnium oxide, or silicon oxide.

[0185] Furthermore, it is preferable to use a material for the sacrificial film 141a that can be dissolved in a solvent that is chemically stable with respect to at least the film 525Rf. In particular, a material that dissolves in water or alcohol is suitable for use as the sacrificial film 141a. When forming the sacrificial film 141a, it is preferable to apply the material dissolved in a solvent such as water or alcohol by a wet film formation method, and then perform a heat treatment to evaporate the solvent. At this time, performing the heat treatment under a reduced pressure atmosphere is preferable because it allows the solvent to be removed at a low temperature and in a short time, thereby reducing thermal damage to the film 525Rf, the layer 512Rf_2, the intermediate film 531Rf, and the layer 512Rf_1.

[0186] Wet film formation methods that can be used to form the sacrificial film 141a include spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, and knife coating.

[0187] The sacrificial film 141a may be made of an organic material such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinyl pyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin.

[0188] Subsequently, a protective film 143a is formed on the sacrificial film 141a (FIG. 12B).

[0189] The protective film 143a is a film used as a hard mask when etching the sacrificial film 141a later. Furthermore, when processing the protective film 143a later, the sacrificial film 141a is exposed. Therefore, a combination of films with a high etching selectivity between the sacrificial film 141a and the protective film 143a is selected. Therefore, a film that can be used for the protective film 143a can be selected depending on the etching conditions for the sacrificial film 141a and the etching conditions for the protective film 143a.

[0190] For example, when dry etching using a gas containing fluorine (also called a fluorine-based gas) is used to etch the protective film 143a, silicon, silicon nitride, silicon oxide, tungsten, titanium, molybdenum, tantalum, tantalum nitride, an alloy containing molybdenum and niobium, an alloy containing molybdenum and tungsten, etc. can be used for the protective film 143a. Here, examples of films that can achieve a large etching selectivity (i.e., a slow etching rate) compared to dry etching using the fluorine-based gas include metal oxide films such as IGZO and ITO, which can be used for the sacrificial film 141a.

[0191] However, the protective film 143a is not limited to this, and can be selected from various materials depending on the etching conditions of the sacrificial film 141a and the etching conditions of the protective film 143a. For example, it can be selected from the films that can be used for the sacrificial film 141a.

[0192] The protective film 143a may be, for example, a nitride film, such as silicon nitride, aluminum nitride, hafnium nitride, titanium nitride, tantalum nitride, tungsten nitride, gallium nitride, or germanium nitride.

[0193] Alternatively, an oxide film can be used as the protective film 143a. Typically, an oxide film or an oxynitride film such as silicon oxide, silicon oxynitride, aluminum oxide, aluminum oxynitride, hafnium oxide, or hafnium oxynitride can be used.

[0194] Subsequently, resist masks 145a are formed on the protective film 143a at positions overlapping the electrode 501R and the connection electrode 501C (FIG. 12C).

[0195] The resist mask 145a can be made of a resist material containing a photosensitive resin, such as a positive resist material or a negative resist material.

[0196] If the resist mask 145a is formed on the sacrificial film 141a without forming the protective film 143a, defects such as pinholes in the sacrificial film 141a may cause the film 525Rf, for example, to dissolve in the solvent of the resist material. By using the protective film 143a, such defects can be prevented.

[0197] When the sacrificial film 141a is made of a film that is less likely to have defects such as pinholes, the resist mask 145a may be formed directly on the sacrificial film 141a without using the protective film 143a.

[0198] Subsequently, a portion of the protective film 143a that is not covered by the resist mask 145a is removed by etching to form a protective layer 149a. At the same time, the protective layer 149a is also formed on the connection electrode 501C.

[0199] When etching the protective film 143a, it is preferable to use etching conditions with a high selectivity so that the sacrificial film 141a is not removed by the etching. The protective film 143a can be etched by wet etching or dry etching, but by using dry etching, it is possible to prevent the pattern of the protective film 143a from shrinking.

[0200] Subsequently, the resist mask 145a is removed (FIG. 12D).

[0201] The resist mask 145a can be removed by wet etching or dry etching. In particular, the resist mask 145a is preferably removed by dry etching (also called plasma ashing) using oxygen gas as an etching gas.

[0202] At this time, the resist mask 145a is removed in a state in which the sacrificial film 141a remains on the film 525Rf, and therefore, the influence on the film 525Rf, the layer 512Rf_2, the intermediate film 531Rf, and the layer 512Rf_1 is suppressed. In particular, if the layers 512Rf_1 and 512Rf_2 come into contact with oxygen, it may adversely affect their electrical characteristics, and therefore, this is suitable for performing etching using oxygen gas, such as plasma ashing.

[0203] Next, using the protective layer 149a as a mask, a portion of the sacrificial film 141a that is not covered by the protective layer 149a is removed by etching to form a sacrificial layer 147a (FIG. 13A). At the same time, the sacrificial layer 147a is also formed on the connection electrode 501C.

[0204] The sacrificial film 141a can be etched by wet etching or dry etching, but dry etching is preferable because it can prevent the pattern from shrinking.

[0205] Next, the protective layer 149a is removed by etching, and portions of the film 525Rf, the layer 512Rf_2, the intermediate film 531Rf, and the layer 512Rf_1 that are not covered by the sacrificial layer 147a are removed by etching to form the layer 525R, the light-emitting unit 512R_2, the intermediate layer 531R, and the light-emitting unit 512R_1 (Figure 13B).

[0206] In particular, dry etching using an etching gas that does not contain oxygen as a main component is preferably used to etch the film 525Rf, the layer 512Rf_2, the intermediate film 531Rf, and the layer 512Rf_1. This suppresses deterioration of the film 525Rf, the layer 512Rf_2, the intermediate film 531Rf, and the layer 512Rf_1, resulting in a highly reliable display device. Examples of etching gases that do not contain oxygen as a main component include CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, H2, and noble gases. Examples of noble gases that can be used include helium. Alternatively, a mixture of any of the above gases and a dilution gas that does not contain oxygen can be used as the etching gas.

[0207] Subsequently, a layer 512Gf_1 that will later become the light-emitting unit 512G_1, an intermediate film 531Gf that will later become the intermediate layer 531G, a layer 512Gf_2 that will later become the light-emitting unit 512G_2, and a film 525Gf that will later become the layer 525G are formed in this order on the sacrificial layer 147a, the insulating layer 131, the electrode 501G, the electrode 501B, and the electrode 501PD. At this time, it is preferable that the layer 512Gf_1, the intermediate film 531Gf, the layer 512Gf_2, and the film 525Gf are not provided on the connection electrode 501C.

[0208] For the film forming methods of the film of the layer 512Gf_1, the intermediate film 531Gf, the film of the layer 512Gf_2, and the film 525Gf, the descriptions of the film forming methods of the film of the layer 512Rf_1, the intermediate film 531Rf, the film of the layer 512Rf_2, and the film 525Rf can be cited.

[0209] Next, a sacrificial film 141b is formed on the film 525Gf. The sacrificial film 141b can be formed by the same method as the sacrificial film 141a. In particular, it is preferable that the sacrificial film 141b is made of the same material as the sacrificial film 141a.

[0210] At the same time, a sacrificial film 141b is formed on the connection electrode 501C, covering the sacrificial layer 147a.

[0211] Next, a protective film 143b is formed on the sacrificial film 141b. The protective film 143b can be formed by the same method as the protective film 143a. In particular, it is preferable that the protective film 143b is made of the same material as the protective film 143a.

[0212] Subsequently, a resist mask 145b is formed on the protective film 143b in a region overlapping with the electrode 501G and a region overlapping with the connection electrode 501C (FIG. 13C).

[0213] The resist mask 145b can be formed in a manner similar to that for the resist mask 145a.

[0214] Subsequently, a portion of the protective film 143b that is not covered by the resist mask 145b is removed by etching to form a protective layer 149b. At the same time, the protective layer 149b is also formed on the connection electrode 501C.

[0215] The above description of the protective film 143a can be applied to the etching of the protective film 143b.

[0216] Next, the resist mask 145b is removed (FIG. 14A). The above description of the resist mask 145a can be applied to the removal of the resist mask 145b.

[0217] Next, using the protective layer 149b as a mask, a portion of the sacrificial film 141b that is not covered by the protective layer 149b is removed by etching to form a sacrificial layer 147b. At the same time, a sacrificial layer 147b is also formed on the connection electrode 501C. The sacrificial layer 147a and the sacrificial layer 147b are stacked on the connection electrode 501C.

[0218] The above description of the sacrificial film 141a can be applied to the etching of the sacrificial film 141b.

[0219] Next, the protective layer 149b is removed by etching, and portions of the film 525Gf, the layer 512Gf_2, the intermediate film 531Gf, and the layer 512Gf_1 that are not covered by the sacrificial layer 147b are removed by etching to form the layer 525G, the light-emitting unit 512G_2, the intermediate layer 531G, and the light-emitting unit 512G_1 (Figure 14B).

[0220] For etching of the film 525Gf, the layer 512Gf_2, the intermediate film 531Gf, the layer 512Gf_1, and the protective layer 149b, the descriptions of the film 525Rf, the layer 512Rf_2, the intermediate film 531Rf, the layer 512Rf_1, and the protective layer 149a can be cited.

[0221] At this time, since the layer 525R, the light-emitting unit 512R_2, the intermediate layer 531R, and the light-emitting unit 512R_1 are protected by the sacrificial layer 147a, they can be prevented from being damaged during the etching process of the film 525Gf, the layer 512Gf_2, the intermediate film 531Gf, and the layer 512Gf_1.

[0222] In this manner, the light emitting unit 512R_1, the intermediate layer 531R, the light emitting unit 512R_2, and the layer 525R, and the light emitting unit 512G_1, the intermediate layer 531G, the light emitting unit 512G_2, and the layer 525G can be separately produced with high positional accuracy.

[0223] By the same processes as those described above, the light-emitting unit 512B_1, the intermediate layer 531B, the light-emitting unit 512B_2, the layer 525B, and the sacrificial layer 147c can be formed (FIG. 14C). The sacrificial layers 147a, 147b, and 147c are stacked on the connection electrode 501C.

[0224] After forming the light-emitting unit 512B_1, the intermediate layer 531B, the light-emitting unit 512B_2, the layer 525B, and the sacrificial layer 147c, the light-receiving unit 542 and the sacrificial layer 147d are formed by the same process as above (FIG. 14D). The sacrificial layers 147a, 147b, 147c, and 147d are stacked on the connection electrode 501C.

[0225] Furthermore, when manufacturing a display device having the light-emitting element 550IR, for example, after forming the light-emitting unit 512B_1, the intermediate layer 531B, the light-emitting unit 512B_2, the layer 525B, and the sacrificial layer 147c, and before forming the light-receiving unit 542 and the sacrificial layer 147d, the light-emitting unit 512IR_1, the intermediate layer 531IR, the light-emitting unit 512IR_2, the layer 525IR, and the sacrificial layer are formed by steps similar to those described above. In this case, five sacrificial layers are stacked on the connection electrode 501C.

[0226] Subsequently, sacrificial layers 147a, 147b, 147c, and 147d are removed to expose the upper surfaces of layers 525R, 525G, 525B, and light-receiving unit 542 (FIG. 15A). At the same time, the upper surface of connection electrode 501C is also exposed.

[0227] The sacrificial layers 147a, 147b, 147c, and 147d can be removed by wet etching or dry etching. At this time, it is preferable to use a method that causes as little damage as possible to the light-emitting unit 512, the intermediate layer 531, the layer 525, and the light-receiving unit 542. In particular, it is preferable to use a wet etching method. For example, it is preferable to use wet etching using a tetramethylammonium hydroxide (TMAH) aqueous solution, dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture thereof.

[0228] Alternatively, it is preferable to remove the sacrificial layers 147a, 147b, 147c, and 147d by dissolving them in a solvent such as water or alcohol. Here, various alcohols such as ethyl alcohol, methyl alcohol, isopropyl alcohol (IPA), or glycerin can be used as the alcohol capable of dissolving the sacrificial layers 147a, 147b, 147c, and 147d.

[0229] After removing the sacrificial layers 147a, 147b, 147c, and 147d, it is preferable to perform a drying treatment to remove water contained inside the light-emitting unit 512, the light-receiving unit 542, etc., and water adsorbed on the surfaces. For example, it is preferable to perform a heat treatment in an inert gas atmosphere or a reduced-pressure atmosphere. The heat treatment can be performed at a substrate temperature of 50°C or higher and 200°C or lower, preferably 60°C or higher and 150°C or lower, and more preferably 70°C or higher and 120°C or lower. A reduced-pressure atmosphere is preferable because it allows drying at a lower temperature.

[0230] In this manner, the light emitting unit 512R, the light emitting unit 512G, the light emitting unit 512B, the light receiving unit 542, etc. can be separately produced.

[0231] Subsequently, the electrode 502 is formed on the layer 525R, the layer 525G, the layer 525B, the light-receiving unit 542, and the connection electrode 501C (FIG. 15B). As described above, a gap can be formed between the electrode 502 and the insulating layer 131.

[0232] The electrode 502 can be formed by a film formation method such as evaporation or sputtering. Alternatively, a film formed by evaporation and a film formed by sputtering may be stacked. The electrode 502 is preferably formed using a shielding mask.

[0233] The electrode 502 is electrically connected to a connection electrode 501C outside the display section.

[0234] Next, the protective layer 125 is formed on the electrode 502 (FIG. 15C). The inorganic insulating film used for the protective layer 125 is preferably formed by sputtering, PECVD, or ALD. The ALD method is particularly preferred because it has excellent step coverage and is less likely to cause defects such as pinholes. The inkjet method is also preferred for forming the organic insulating film because it can form a uniform film in the desired area.

[0235] In this manner, the display device 10 can be manufactured.

[0236] As described above, in the method for manufacturing a display device according to one embodiment of the present invention, the light-emitting element 550 can be individually fabricated without using a shadow mask such as a metal mask. This allows the subpixels to be miniaturized and the pixel aperture ratio to be increased compared to the case where the light-emitting element 550 is individually fabricated using a shadow mask. Furthermore, because the light-emitting units 512 can be individually fabricated, a display device with extremely vivid, high-contrast, and high display quality can be realized.

[0237] By miniaturizing the subpixels, subpixels that do not contribute to display can be provided in the pixel. For example, a subpixel having a light-receiving element 560 can be provided in the pixel, and a subpixel having a light-emitting element 550IR that emits infrared light can be provided in the pixel. In the display device of one embodiment of the present invention, even when such subpixels that do not contribute to display are provided in the pixel, the pixel density can be prevented from becoming low. For example, the pixel density can be 400 ppi or more, 1000 ppi or more, 3000 ppi or more, or 5000 ppi or more.

[0238] At least a part of the configuration examples exemplified in this embodiment and the corresponding drawings can be combined as appropriate with other configuration examples or drawings.

[0239] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0240] (Embodiment 2) In this embodiment, a structural example of a display device according to one embodiment of the present invention will be described.

[0241] [Configuration example 1] Fig. 16 is a perspective view showing an example of the configuration of the display device 100. The display device 100 has a configuration in which a substrate 151 and a substrate 152 are bonded together. In Fig. 16, the substrate 152 is indicated by a dashed line.

[0242] The display device 100 has a display unit 162, a circuit 164, wiring 165, etc. Fig. 16 also shows an example in which an IC (integrated circuit) 173 and an FPC 172 are mounted on the display device 100. Therefore, the configuration shown in Fig. 16 can also be said to be a display module having a display device, an IC, and an FPC.

[0243] The circuit 164 may be, for example, a gate driver. For example, signals and power may be supplied to the circuit 164 via wiring 165. The signals and power may be input to the wiring 165 via an FPC 172 from outside the display device 10. Alternatively, the signals and power may be generated by an IC 173 and output to the wiring 165.

[0244] FIG. 16 shows an example in which the IC 173 is provided on the substrate 151 by a COG (Chip On Glass) method, but a TCP (Tape Carrier Package) method, a COF (Chip On Film) method, or the like may also be used.

[0245] Fig. 17 is a diagram showing an example of a cross section of a part of an area including FPC 172, a part of an area including circuit 164, a part of an area including display unit 162, and a part of an area including an end portion in display device 100 shown in Fig. 16. Note that display device 100 shown in Fig. 17 is referred to as display device 100A.

[0246] The display device 100A includes a transistor 201, a transistor 141, a transistor 142, a light-emitting element 550, a light-receiving element 560, and the like between a substrate 151 and a substrate 152.

[0247] The substrate 152 and the insulating layer 214 are bonded via an adhesive layer 242. A solid sealing structure, a hollow sealing structure, or the like can be applied to seal the light-emitting element 550 and the light-receiving element 560. A space 143 surrounded by the substrate 152, the adhesive layer 242, and the insulating layer 214 is filled with an inert gas (nitrogen, argon, or the like), and a hollow sealing structure is applied. The adhesive layer 242 may be provided so as to overlap the light-emitting element 550. Furthermore, the region surrounded by the substrate 152, the adhesive layer 242, and the insulating layer 214 may be filled with a resin different from the adhesive layer 242.

[0248] An electrode 501 included in the light-emitting element 550 is electrically connected to a conductive layer 222b included in the transistor 141 through an opening provided in the insulating layer 214. The transistor 142 has a function of controlling driving of the light-emitting element 550. An electrode 501PD included in the light-receiving element 560 is electrically connected to a conductive layer 222b included in the transistor 142 through an opening provided in the insulating layer 214.

[0249] Light emitted by light-emitting element 550 is emitted toward substrate 152. Light is incident on light-receiving element 560 through substrate 152 and space 143. For substrate 152, it is preferable to use a material that is highly transparent to visible light and infrared light.

[0250] A light-shielding layer 148 is provided on the surface of the substrate 152 facing the substrate 151. The light-shielding layer 148 has openings at positions overlapping the light-receiving element 560 and the light-emitting element 550. A filter 146 that cuts ultraviolet light is provided at the position overlapping the light-receiving element 560. Note that a configuration in which the filter 146 is not provided is also possible.

[0251] The transistor 201, the transistor 141, and the transistor 142 are all formed over a substrate 151. These transistors can be manufactured using the same material and through the same process.

[0252] An insulating layer 211, an insulating layer 213, an insulating layer 215, and an insulating layer 214 are provided over the substrate 151 in this order. A part of the insulating layer 211 functions as a gate insulating layer for each transistor. A part of the insulating layer 213 functions as a gate insulating layer for each transistor. The insulating layer 215 is provided to cover the transistor. The insulating layer 214 is provided to cover the transistor and functions as a planarization layer. Note that the number of gate insulating layers and the number of insulating layers covering the transistors are not limited, and each may be a single layer or two or more layers.

[0253] At least one insulating layer covering the transistor is preferably made of a material that is resistant to the diffusion of impurities such as water or hydrogen. This allows the insulating layer to function as a barrier layer. With this structure, it is possible to effectively prevent impurities from diffusing into the transistor from the outside, thereby improving the reliability of the display device.

[0254] The insulating layer 211, the insulating layer 213, and the insulating layer 215 are preferably formed using an inorganic insulating film. Examples of the inorganic insulating film that can be used include a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon nitride oxide film, an aluminum oxide film, and an aluminum nitride film. Alternatively, a hafnium oxide film, an yttrium oxide film, a zirconium oxide film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, and a neodymium oxide film may be used. Two or more of the above insulating films may be stacked.

[0255] An organic insulating film is preferably used for the insulating layer 214, which functions as a planarizing layer. Materials that can be used for the organic insulating film include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimideamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins.

[0256] Here, organic insulating films often have a lower barrier property against impurities than inorganic insulating films. Therefore, it is preferable that the organic insulating film has an opening near the edge of the display device 100A. This makes it possible to prevent impurities from diffusing from the edge of the display device 100A through the organic insulating film. Alternatively, the organic insulating film may be formed so that the edge of the organic insulating film is located inside the edge of the display device 100A, so that the organic insulating film is not exposed at the edge of the display device 100A.

[0257] 17, an opening is formed in the insulating layer 214. This makes it possible to prevent impurities from diffusing from the outside into the display unit 162 through the insulating layer 214, even when an organic insulating film is used for the insulating layer 214. This makes it possible to improve the reliability of the display device 100A.

[0258] The transistor 201, the transistor 141, and the transistor 142 each include a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, conductive layers 222a and 222b that function as a source and a drain, a semiconductor layer 231, an insulating layer 213 that functions as a gate insulating layer, and a conductive layer 223 that functions as a gate. Here, the same hatching pattern is applied to multiple layers obtained by processing the same conductive film. The insulating layer 211 is located between the conductive layer 221 and the semiconductor layer 231. The insulating layer 213 is located between the conductive layer 223 and the semiconductor layer 231.

[0259] The structure of the transistor included in the display device of this embodiment is not particularly limited. For example, a planar transistor, a staggered transistor, an inverted staggered transistor, or the like can be used. Furthermore, either a top-gate transistor or a bottom-gate transistor structure may be used. Alternatively, gates may be provided above and below a semiconductor layer in which a channel is formed.

[0260] The transistor 201, the transistor 141, and the transistor 142 each have a structure in which a semiconductor layer in which a channel is formed is sandwiched between two gates. The two gates may be connected and supplied with the same signal to drive the transistor. Alternatively, a potential for controlling the threshold voltage of the transistor may be applied to one of the two gates, and a potential for driving the transistor may be applied to the other gate.

[0261] The crystallinity of a semiconductor material used for a transistor is not particularly limited, and any of an amorphous semiconductor, a single-crystal semiconductor, and a semiconductor having crystallinity other than single crystal (a microcrystalline semiconductor, a polycrystalline semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a single-crystal semiconductor or a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0262] The semiconductor layer of the transistor preferably contains a metal oxide (also referred to as an oxide semiconductor). Alternatively, the semiconductor layer of the transistor may contain silicon. Examples of silicon include amorphous silicon and crystalline silicon (low-temperature polysilicon, single-crystal silicon, or the like).

[0263] When the semiconductor layer contains a metal oxide, the metal oxide preferably contains at least indium or zinc, as described above. It is particularly preferable that the metal oxide contains indium and zinc. Furthermore, it is preferable that the metal oxide further contains aluminum, gallium, yttrium, tin, or the like. Furthermore, the metal oxide may contain one or more elements selected from boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, cobalt, and the like.

[0264] The transistors included in the circuit 164 and the transistors included in the display portion 162 may have the same structure or different structures. The transistors included in the circuit 164 may all have the same structure or may have two or more types. Similarly, the transistors included in the display portion 162 may all have the same structure or may have two or more types.

[0265] A connection portion 204 is provided in an area of ​​the substrate 151 where the substrate 152 does not overlap. In the connection portion 204, the wiring 165 is electrically connected to the FPC 172 via the conductive layer 166 and the connection layer 244. The conductive layer 166, which is obtained by processing the same conductive film as the electrode 501, is exposed on the upper surface of the connection portion 204. This allows the connection portion 204 and the FPC 172 to be electrically connected via the connection layer 244.

[0266] Various optical members can be disposed on the outside of the substrate 152. Examples of optical members include a polarizing plate, a retardation plate, a light diffusion layer (such as a diffusion film), an anti-reflection layer, and a light collecting film. In addition, an antistatic film that suppresses the adhesion of dust, a water-repellent film that makes it difficult for dirt to adhere, a hard coat film that suppresses the occurrence of scratches during use, or an impact absorbing layer may be disposed on the outside of the substrate 152.

[0267] The substrates 151 and 152 may be made of glass, quartz, ceramic, sapphire, resin, or the like.

[0268] The adhesive layer can be made of various curable adhesives, such as photo-curable adhesives (e.g., ultraviolet curable), reactive curable adhesives, thermosetting adhesives, or anaerobic adhesives. Examples of such adhesives include epoxy resin, acrylic resin, silicone resin, phenolic resin, polyimide resin, imide resin, PVC (polyvinyl chloride) resin, PVB (polyvinyl butyral) resin, and EVA (ethylene vinyl acetate) resin. Materials with low moisture permeability, such as epoxy resin, are particularly preferred. Two-component resins may also be used. Alternatively, an adhesive sheet may be used.

[0269] The connection layer 244 may be an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), or the like.

[0270] Materials that can be used for the gate, source, and drain of a transistor as well as conductive layers such as various wirings and electrodes that constitute a display device include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, and tungsten, and alloys containing these metals as main components, etc. Films containing these materials can be used as a single-layer structure or a stacked-layer structure.

[0271] Examples of light-transmitting conductive materials include conductive oxides such as indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, and zinc oxide containing gallium. Alternatively, graphene can be used. Metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, and titanium, as well as alloy materials containing these metal materials, can be used. Alternatively, nitrides of these metal materials (e.g., titanium nitride) can be used. When using metal materials or alloy materials (or their nitrides), it is preferable to thin them thin enough to have light-transmitting properties. A stacked film of the above materials can also be used as the conductive layer. For example, a stacked film of an alloy of silver and magnesium and indium tin oxide is preferable because it can enhance conductivity. These can also be used for conductive layers such as various wirings and electrodes constituting a display device, and conductive layers (conductive layers functioning as pixel electrodes or common electrodes) in display elements.

[0272] Examples of insulating materials that can be used for each insulating layer include resins such as acrylic resin and epoxy resin, and inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, and aluminum oxide.

[0273] [Configuration example 2] 18 is a cross-sectional view showing an example of the configuration of display device 100B, which is a modification of display device 100A. Display device 100B differs from display device 100A in that display device 100B has substrate 153, adhesive layer 155, and insulating layer 212 instead of substrate 151, and has substrate 154, adhesive layer 156, and insulating layer 158 instead of substrate 152.

[0274] In the display device 100B, the substrate 153 and the insulating layer 212 are bonded together by an adhesive layer 155. Furthermore, the substrate 154 and the insulating layer 158 are bonded together by an adhesive layer 156.

[0275] When manufacturing the display device 100B shown in FIG. 18 , first, a first manufacturing substrate provided with the insulating layer 212, the transistors, the light-emitting element 550, the light-receiving element 560, and the like is bonded to a second manufacturing substrate provided with the insulating layer 158, the light-shielding layer 148, the filter 146, and the like using an adhesive layer 242. Then, the first manufacturing substrate is peeled off, and a substrate 153 is attached to the exposed surface using an adhesive layer 155. In this way, the components formed on the first manufacturing substrate are transferred to the substrate 153. In addition, the second manufacturing substrate is peeled off, and a substrate 154 is attached to the exposed surface using an adhesive layer 156. In this way, the components formed on the second manufacturing substrate are transferred to the substrate 154. The substrate 153 and the substrate 154 are preferably flexible. This allows the display device 100B to have flexibility. That is, the display device 100B can be a flexible display.

[0276] The insulating layer 212 and the insulating layer 158 can be formed using the inorganic insulating film that can be used for the insulating layer 211, the insulating layer 213, and the insulating layer 215, respectively.

[0277] [Configuration example 3] 19 is a cross-sectional view showing an example of the configuration of a display device 100C. The display device 100C has a substrate 301, a light-emitting element 550, a light-receiving element 560, a capacitor 240, and a transistor 310. The substrate 301 corresponds to, for example, the substrate 151 in FIG.

[0278] The transistor 310 has a channel formation region in a substrate 301. The substrate 301 can be, for example, a semiconductor substrate such as a single crystal silicon substrate. The transistor 310 includes a part of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region in which the substrate 301 is doped with impurities and functions as a source or drain. The insulating layer 314 is provided to cover a side surface of the conductive layer 311.

[0279] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0280] In addition, an insulating layer 261 is provided to cover the transistor 310 , and a capacitor 240 is provided over the insulating layer 261 .

[0281] Capacitor 240 has conductive layer 241, conductive layer 245, and insulating layer 243 positioned therebetween. Conductive layer 241 functions as one electrode of capacitor 240, conductive layer 245 functions as the other electrode of capacitor 240, and insulating layer 243 functions as a dielectric of capacitor 240.

[0282] The conductive layer 241 is provided over the insulating layer 261 and is buried in the insulating layer 254. The conductive layer 241 is electrically connected to one of the source and drain of the transistor 310 by a plug 271 buried in the insulating layer 261. The insulating layer 243 is provided to cover the conductive layer 241. The conductive layer 245 is provided in a region overlapping with the conductive layer 241 with the insulating layer 243 interposed therebetween.

[0283] An insulating layer 255 is provided to cover the capacitor 240, and a light emitting element 550, a light receiving element 560, and the like are provided on the insulating layer 255. A protective layer 125 is provided on the light emitting element 550 and the light receiving element 560, and a substrate 420 is bonded to the upper surface of the protective layer 125 by a resin layer 419. The substrate 420 corresponds to, for example, the substrate 152 in FIG. 16 .

[0284] The electrode 501 of the light-emitting element 550 and the electrode 501PD of the light-receiving element 560 are electrically connected to either the source or drain of the transistor 310 by the insulating layer 255, the plug 256 embedded in the insulating layer 243, the conductive layer 241 embedded in the insulating layer 254, and the plug 271 embedded in the insulating layer 261.

[0285] [Configuration example 4] 20 is a cross-sectional view showing an example of the configuration of the display device 100D. The display device 100D differs from the display device 100C mainly in the configuration of the transistors. Note that descriptions of parts that are the same as those of the display device 100C may be omitted.

[0286] The transistor 320 is a transistor in which a metal oxide is used for a semiconductor layer in which a channel is formed (hereinafter also referred to as an OS transistor).

[0287] The transistor 320 includes a semiconductor layer 321 , an insulating layer 323 , a conductive layer 324 , a pair of conductive layers 325 , an insulating layer 326 , and a conductive layer 327 .

[0288] The substrate 331 corresponds to, for example, the substrate 151 in Fig. 16. The substrate 331 may be an insulating substrate or a semiconductor substrate.

[0289] An insulating layer 332 is provided over a substrate 331. The insulating layer 332 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the substrate 331 to the transistor 320 and prevents oxygen from being released from the semiconductor layer 321 toward the insulating layer 332. The insulating layer 332 can be, for example, a film through which hydrogen or oxygen is less likely to diffuse than a silicon oxide film, such as an aluminum oxide film, a hafnium oxide film, or a silicon nitride film.

[0290] A conductive layer 327 is provided over the insulating layer 332, and an insulating layer 326 is provided to cover the conductive layer 327. The conductive layer 327 functions as a first gate electrode of the transistor 320, and part of the insulating layer 326 functions as a first gate insulating layer. An oxide insulating film such as a silicon oxide film is preferably used for at least a portion of the insulating layer 326 that is in contact with the semiconductor layer 321. The top surface of the insulating layer 326 is preferably planarized.

[0291] The semiconductor layer 321 is provided over the insulating layer 326. The semiconductor layer 321 preferably includes a metal oxide film having semiconductor properties.

[0292] A pair of conductive layers 325 is provided over and in contact with the semiconductor layer 321 and functions as a source electrode and a drain electrode.

[0293] An insulating layer 328 is provided to cover top surfaces and side surfaces of the pair of conductive layers 325 and side surfaces of the semiconductor layer 321, and an insulating layer 264 is provided over the insulating layer 328. The insulating layer 328 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 264 or the like to the semiconductor layer 321 and prevents oxygen from being released from the semiconductor layer 321. The insulating layer 328 can be formed using an insulating film similar to the insulating layer 332.

[0294] An opening is provided in the insulating layer 328 and the insulating layer 264, reaching the semiconductor layer 321. An insulating layer 323 and a conductive layer 324 are buried inside the opening and are in contact with the side surfaces of the insulating layer 264, the insulating layer 328, and the conductive layer 325, as well as the top surface of the semiconductor layer 321. The conductive layer 324 functions as a second gate electrode, and the insulating layer 323 functions as a second gate insulating layer.

[0295] The upper surfaces of the conductive layer 324, the insulating layer 323, and the insulating layer 264 are planarized so that their heights are approximately the same, and insulating layers 329 and 265 are provided to cover them.

[0296] The insulating layer 264 and the insulating layer 265 function as interlayer insulating layers. The insulating layer 329 functions as a barrier layer that prevents impurities such as water or hydrogen from diffusing from the insulating layer 265 or the like to the transistor 320. The insulating layer 329 can be formed using an insulating film similar to the insulating layer 328 and the insulating layer 332.

[0297] The plug 274 electrically connected to one of the pair of conductive layers 325 is provided to be embedded in the insulating layer 265, the insulating layer 329, the insulating layer 264, and the insulating layer 328. Here, the plug 274 preferably includes a conductive layer 274a covering side surfaces of the openings in the insulating layer 265, the insulating layer 329, the insulating layer 264, and the insulating layer 328 and part of the top surface of the conductive layer 325, and a conductive layer 274b in contact with the top surface of the conductive layer 274a. In this case, the conductive layer 274a is preferably made of a conductive material through which hydrogen and oxygen do not easily diffuse.

[0298] The configuration of the display device 100D from the insulating layer 254 to the substrate 420 is the same as that of the display device 100C.

[0299] [Configuration example 5] 21 is a cross-sectional view showing a configuration example of a display device 100E. The display device 100E has a configuration in which a transistor 310 having a channel formed in a substrate 301 and a transistor 320 having a channel formed in a semiconductor layer containing a metal oxide are stacked. Note that descriptions of parts similar to those of the display device 100C or the display device 100D may be omitted.

[0300] An insulating layer 261 is provided to cover the transistor 310, and a conductive layer 251 is provided over the insulating layer 261. An insulating layer 262 is provided to cover the conductive layer 251, and a conductive layer 252 is provided over the insulating layer 262. The conductive layers 251 and 252 each function as wirings. An insulating layer 263 and an insulating layer 332 are provided to cover the conductive layer 252, and a transistor 320 is provided over the insulating layer 332. An insulating layer 265 is provided to cover the transistor 320, and a capacitor 240 is provided over the insulating layer 265. The capacitor 240 and the transistor 320 are electrically connected by a plug 274.

[0301] The transistor 320 can be used as a transistor included in a pixel circuit. The transistor 310 can be used as a transistor included in a pixel circuit or a driver circuit (gate line driver circuit, source line driver circuit) for driving the pixel circuit. The transistors 310 and 320 can be used as transistors included in various circuits such as an arithmetic circuit or a memory circuit.

[0302] By using this configuration, not only the pixel circuit but also, for example, a driver circuit can be formed directly below the light-emitting element, which makes it possible to make the display device smaller than when the driver circuit is provided around the display unit.

[0303] At least a part of the configuration examples exemplified in this embodiment and the corresponding drawings can be combined as appropriate with other configuration examples or drawings.

[0304] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0305] (Embodiment 3) In this embodiment, a metal oxide that can be used for the OS transistor described in the above embodiment will be described.

[0306] The metal oxide preferably contains at least indium or zinc. It is particularly preferable that it contains indium and zinc. Furthermore, it is preferable that it contains aluminum, gallium, yttrium, tin, or the like in addition to these. It may also contain one or more elements selected from boron, silicon, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, magnesium, cobalt, and the like.

[0307] The metal oxide can be formed by a sputtering method, a CVD method such as an MOCVD method, or an ALD method.

[0308] <Classification of crystal structures> Examples of the crystalline structure of oxide semiconductors include amorphous (including completely amorphous), c-axis-aligned crystalline (CAAC), nanocrystalline (nc), cloud-aligned composite (CAC), single crystal, and polycrystal.

[0309] The crystalline structure of the film or substrate can be evaluated using X-ray diffraction (XRD) spectra. For example, it can be evaluated using XRD spectra obtained by GIXD (Grazing-Incidence XRD) measurements. The GIXD method is also called the thin film method or the Seemann-Bohlin method.

[0310] For example, in the case of a quartz glass substrate, the peak shape of the XRD spectrum is nearly symmetrical. On the other hand, in the case of an IGZO film having a crystalline structure, the peak shape of the XRD spectrum is asymmetrical. The asymmetrical peak shape of the XRD spectrum clearly indicates the presence of crystals in the film or substrate. In other words, if the peak shape of the XRD spectrum is not symmetrical, the film or substrate cannot be said to be in an amorphous state.

[0311] The crystalline structure of a film or substrate can be evaluated by a diffraction pattern (also called a nanobeam electron diffraction pattern) observed using nanobeam electron diffraction (NBED). For example, a halo is observed in the diffraction pattern of a quartz glass substrate, confirming that the quartz glass is in an amorphous state. Furthermore, a spot-like pattern is observed in the diffraction pattern of an IGZO film deposited at room temperature, rather than a halo. For this reason, it is estimated that an IGZO film deposited at room temperature is neither crystalline nor amorphous, but is in an intermediate state, and it cannot be concluded that it is in an amorphous state.

[0312] <<Oxide semiconductor structure>> Note that oxide semiconductors may be classified differently from the above when focusing on their structures. For example, oxide semiconductors are divided into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. Examples of non-single-crystal oxide semiconductors include the above-mentioned CAAC-OS and nc-OS. Non-single-crystal oxide semiconductors include polycrystalline oxide semiconductors, amorphous-like oxide semiconductors (a-like OSs), amorphous oxide semiconductors, and the like.

[0313] Here, the above-mentioned CAAC-OS, nc-OS, and a-like OS will be described in detail.

[0314] [CAAC-OS] CAAC-OS is an oxide semiconductor having multiple crystalline regions, each with its c-axis aligned in a specific direction. The specific direction can be the thickness direction of the CAAC-OS film, the normal direction to the surface on which the CAAC-OS film is formed, or the normal direction to the surface of the CAAC-OS film. A crystalline region is a region with periodic atomic arrangement. Considering an atomic arrangement as a lattice arrangement, a crystalline region can also be a region with a uniform lattice arrangement. Furthermore, CAAC-OS has a region where multiple crystalline regions are connected in the ab-plane direction, and the region may have distortion. The distortion refers to a location where the lattice orientation changes between a region with a uniform lattice arrangement and a region with a different uniform lattice arrangement in the region where multiple crystalline regions are connected. In other words, CAAC-OS is an oxide semiconductor with a c-axis aligned but no clear orientation in the ab-plane direction.

[0315] Each of the multiple crystalline regions is composed of one or more minute crystals (crystals with a maximum diameter of less than 10 nm). When a crystalline region is composed of one minute crystal, the maximum diameter of the crystalline region is less than 10 nm. When a crystalline region is composed of many minute crystals, the size of the crystalline region may be several tens of nm.

[0316] In an In-M-Zn oxide (wherein element M is one or more elements selected from aluminum, gallium, yttrium, tin, titanium, etc.), the CAAC-OS tends to have a layered crystal structure (also referred to as a layered structure) in which a layer containing indium (In) and oxygen (hereinafter referred to as an In layer) and a layer containing element M, zinc (Zn), and oxygen (hereinafter referred to as an (M, Zn) layer) are stacked. Note that indium and element M are mutually substituted. Therefore, the (M, Zn) layer may contain indium. Furthermore, the In layer may contain element M. Furthermore, the In layer may contain Zn. The layered structure is observed as a lattice image in, for example, a high-resolution transmission electron microscope (TEM) image.

[0317] When the CAAC-OS film is subjected to structural analysis using, for example, an XRD apparatus, a peak indicating c-axis orientation is detected at or near 2θ=31° in out-of-plane XRD measurement using θ / 2θ scan. Note that the position of the peak indicating c-axis orientation (2θ value) may vary depending on the type or composition of the metal elements constituting the CAAC-OS.

[0318] For example, in the electron diffraction pattern of a CAAC-OS film, multiple bright spots are observed, and the spots are observed at positions that are point-symmetric with respect to the spot of the incident electron beam that has passed through the sample (also called the direct spot).

[0319] When the crystalline region is observed from the specific direction, the lattice arrangement in the crystalline region is basically a hexagonal lattice, but the unit cell is not necessarily a regular hexagon and may be non-regular hexagonal. The distortion may also have a pentagonal or heptagonal lattice arrangement. In the CAAC-OS, no clear grain boundaries can be identified even near the distortion. This indicates that the formation of grain boundaries is suppressed by the distortion of the lattice arrangement. This is thought to be because the CAAC-OS can tolerate distortion due to the lack of close-packed arrangement of oxygen atoms in the ab-plane direction or the change in interatomic bond distance caused by metal atom substitution.

[0320] A crystal structure with clear grain boundaries is called polycrystalline. Grain boundaries act as recombination centers, trapping carriers and potentially reducing the on-state current or field-effect mobility of a transistor. Therefore, CAAC-OS, which lacks clear grain boundaries, is one of the crystalline oxides with a crystal structure suitable for use in a transistor semiconductor layer. Zn is preferred for use in CAAC-OS. For example, In-Zn oxide and In-Ga-Zn oxide are suitable because they can suppress the generation of grain boundaries more effectively than In oxide.

[0321] CAAC-OS is an oxide semiconductor with high crystallinity and no clear crystal grain boundaries. Therefore, it can be said that the CAAC-OS is less susceptible to a decrease in electron mobility due to crystal grain boundaries. Furthermore, since the crystallinity of an oxide semiconductor can be reduced by the inclusion of impurities or the formation of defects, the CAAC-OS can also be said to be an oxide semiconductor with few impurities and defects (such as oxygen vacancies). Therefore, oxide semiconductors with CAAC-OS have stable physical properties. Therefore, oxide semiconductors with CAAC-OS are heat-resistant and highly reliable. Furthermore, the CAAC-OS is stable even under high temperatures (so-called thermal budgets) during the manufacturing process. Therefore, using a CAAC-OS for an OS transistor can increase the flexibility of the manufacturing process.

[0322] [nc-OS] The nc-OS has periodic atomic arrangement in a microscopic region (e.g., a region of 1 nm to 10 nm, particularly a region of 1 nm to 3 nm). In other words, the nc-OS has microcrystals. Note that the size of the microcrystals is, for example, 1 nm to 10 nm, particularly 1 nm to 3 nm, and therefore the microcrystals are also called nanocrystals. Furthermore, the nc-OS exhibits no regularity in the crystal orientation between different nanocrystals. Therefore, no orientation is observed throughout the film. Therefore, depending on the analytical method, the nc-OS may be indistinguishable from an a-like OS or an amorphous oxide semiconductor. For example, when a structural analysis of an nc-OS film is performed using an XRD apparatus, no peaks indicating crystallinity are detected in out-of-plane XRD measurements using θ / 2θ scanning. Furthermore, when an nc-OS film is subjected to electron diffraction (also known as selected-area electron diffraction) using an electron beam with a probe diameter larger than that of nanocrystals (e.g., 50 nm or larger), a halo-like diffraction pattern is observed. On the other hand, when electron diffraction (also called nanobeam electron diffraction) is performed on an nc-OS film using an electron beam with a probe diameter close to or smaller than the size of the nanocrystals (for example, 1 nm to 30 nm), an electron diffraction pattern can be obtained in which multiple spots are observed within a ring-shaped region centered on the direct spot.

[0323] [a-like OS] The a-like OS is an oxide semiconductor having a structure between the nc-OS and the amorphous oxide semiconductor. The a-like OS has a pore or low-density region. That is, the a-like OS has lower crystallinity than the nc-OS and CAAC-OS. Furthermore, the a-like OS has a higher hydrogen concentration in the film than the nc-OS and CAAC-OS.

[0324] <<Oxide semiconductor structure>> Next, the above-mentioned CAC-OS will be described in detail, which relates to the material composition.

[0325] [CAC-OS] CAC-OS is a material structure in which elements constituting a metal oxide are unevenly distributed in a size range of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or in the vicinity thereof. Note that, hereinafter, a metal oxide in which one or more metal elements are unevenly distributed and the regions containing the metal elements are mixed in a size range of 0.5 nm to 10 nm, preferably 1 nm to 3 nm, or in the vicinity thereof, is also referred to as a mosaic or patch state.

[0326] Furthermore, CAC-OS has a mosaic structure in which the material is separated into first and second regions, and the first regions are distributed throughout the film (hereinafter also referred to as a cloud structure). That is, CAC-OS is a composite metal oxide having a structure in which the first and second regions are mixed.

[0327] Here, the atomic ratios of In, Ga, and Zn to the metal elements constituting the CAC-OS in the In-Ga-Zn oxide are represented as [In], [Ga], and [Zn], respectively. For example, in the CAC-OS in the In-Ga-Zn oxide, the first region is a region where [In] is larger than [In] in the CAC-OS composition. The second region is a region where [Ga] is larger than [Ga] in the CAC-OS composition. Alternatively, for example, the first region is a region where [In] is larger than [In] in the second region and [Ga] is smaller than [Ga] in the second region. The second region is a region where [Ga] is larger than [Ga] in the first region and [In] is smaller than [In] in the first region.

[0328] Specifically, the first region is a region whose main components are indium oxide, indium zinc oxide, etc. The second region is a region whose main components are gallium oxide, gallium zinc oxide, etc. That is, the first region can be rephrased as a region whose main component is In. The second region can be rephrased as a region whose main component is Ga.

[0329] It should be noted that there are cases where a clear boundary between the first region and the second region cannot be observed.

[0330] In addition, CAC-OS in In-Ga-Zn oxide refers to a material structure containing In, Ga, Zn, and O, in which some regions primarily composed of Ga and other regions primarily composed of In are randomly arranged in a mosaic pattern. Therefore, it is presumed that CAC-OS has a structure in which metal elements are distributed nonuniformly.

[0331] The CAC-OS can be formed, for example, by a sputtering method under conditions where the substrate is not intentionally heated. When the CAC-OS is formed by a sputtering method, one or more of an inert gas (typically argon), oxygen gas, and nitrogen gas may be used as the deposition gas. The lower the flow rate ratio of oxygen gas to the total flow rate of deposition gas during deposition, the more preferable it is. For example, the flow rate ratio of oxygen gas to the total flow rate of deposition gas during deposition is preferably 0% or more and less than 30%, and more preferably 0% or more and 10% or less.

[0332] Furthermore, for example, in the case of CAC-OS in an In-Ga-Zn oxide, EDX mapping obtained using EDX (Energy Dispersive X-ray spectroscopy) confirms that the CAC-OS has a structure in which a region containing In as a main component (first region) and a region containing Ga as a main component (second region) are unevenly distributed and mixed.

[0333] Here, the first region has higher conductivity than the second region. That is, the flow of carriers through the first region causes the metal oxide to exhibit conductivity. Therefore, the first region is distributed in a cloud-like manner in the metal oxide, thereby achieving a high field-effect mobility (μ).

[0334] On the other hand, the second region has higher insulating properties than the first region. That is, the second region is distributed in the metal oxide, thereby suppressing leakage current.

[0335] Therefore, when CAC-OS is used in a transistor, the conductivity due to the first region and the insulating property due to the second region act complementarily, thereby providing the CAC-OS with a switching function (the ability to turn on / off). In other words, CAC-OS has a conductive function in part of the material and an insulating function in part of the material, and the material as a whole functions as a semiconductor. By separating the conductive function from the insulating function, both functions can be maximized. Therefore, by using CAC-OS in a transistor, a high on-current (I on ), high field-effect mobility (μ), and good switching behavior can be achieved.

[0336] Furthermore, a transistor using CAC-OS has high reliability, making it ideal for various semiconductor devices such as display devices.

[0337] Oxide semiconductors have a variety of structures and each has different characteristics. The oxide semiconductor of one embodiment of the present invention may include two or more of an amorphous oxide semiconductor, a polycrystalline oxide semiconductor, an a-like OS, a CAC-OS, an nc-OS, and a CAAC-OS.

[0338] <Transistors containing oxide semiconductors> Next, a case where the oxide semiconductor is used in a transistor will be described.

[0339] By using the oxide semiconductor for a transistor, a transistor with high field-effect mobility and high reliability can be realized.

[0340] For the transistor, an oxide semiconductor with a low carrier concentration is preferably used. For example, the carrier concentration of the oxide semiconductor is 1×10 17 cm -3 Less than 1 × 10 15 cm -3 or less, more preferably 1 × 10 13 cm -3Less than or equal to 1×10 11 cm -3 or less, more preferably 1 × 10 10 cm -3 Less than 1 x 10 -9 cm -3 The above is the case. Note that in order to reduce the carrier concentration of an oxide semiconductor film, the impurity concentration in the oxide semiconductor film may be reduced to reduce the density of defect states. In this specification and the like, a semiconductor having a low impurity concentration and a low density of defect states is referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor. Note that an oxide semiconductor having a low carrier concentration may also be referred to as a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor.

[0341] Furthermore, a highly purified intrinsic or substantially highly purified intrinsic oxide semiconductor film has a low density of defect states, and therefore the density of trap states may also be low.

[0342] Furthermore, charges trapped in the trap states of an oxide semiconductor take a long time to dissipate and may behave like fixed charges. Therefore, a transistor in which a channel formation region is formed in an oxide semiconductor with a high density of trap states may have unstable electrical characteristics.

[0343] Therefore, in order to stabilize the electrical characteristics of a transistor, it is effective to reduce the impurity concentration in the oxide semiconductor. Furthermore, in order to reduce the impurity concentration in the oxide semiconductor, it is preferable to also reduce the impurity concentration in the adjacent film. Examples of impurities include hydrogen, nitrogen, alkali metals, alkaline earth metals, iron, nickel, and silicon.

[0344] <Impurities> Here, the influence of each impurity in an oxide semiconductor will be described.

[0345] When an oxide semiconductor contains silicon or carbon, which is one of the Group 14 elements, defect levels are formed in the oxide semiconductor. Therefore, the concentration of silicon or carbon in the oxide semiconductor and the concentration of silicon or carbon near the interface with the oxide semiconductor (concentration obtained by secondary ion mass spectrometry (SIMS)) are calculated to be 2×10 18 atoms / cm 3 Less than or equal to 2 x 10 17 atoms / cm 3 The following applies.

[0346] Furthermore, when an oxide semiconductor contains an alkali metal or alkaline earth metal, defect levels may be formed and carriers may be generated. Therefore, a transistor using an oxide semiconductor containing an alkali metal or alkaline earth metal is likely to have normally-on characteristics. For this reason, when the concentration of the alkali metal or alkaline earth metal in the oxide semiconductor obtained by SIMS is 1×10 18 atoms / cm 3 Less than or equal to 2 x 10 16 atoms / cm 3 Do the following:

[0347] Furthermore, when nitrogen is contained in an oxide semiconductor, electrons serving as carriers are generated, the carrier concentration increases, and the semiconductor is likely to become n-type. As a result, a transistor using an oxide semiconductor containing nitrogen as a semiconductor tends to have normally-on characteristics. Alternatively, when nitrogen is contained in an oxide semiconductor, trap states may be formed. As a result, the electrical characteristics of the transistor may become unstable. For this reason, the nitrogen concentration in the oxide semiconductor obtained by SIMS is set to 5×10 19 atoms / cm 3 Less than 5 x 10 18 atoms / cm 3 Less than or equal to 1×10 18 atoms / cm 3 Less than 5 × 10, more preferably 17 atoms / cm 3 Do the following:

[0348] Furthermore, hydrogen contained in an oxide semiconductor may react with oxygen bonded to a metal atom to form water, which may form an oxygen vacancy. When hydrogen enters the oxygen vacancy, electrons serving as carriers may be generated. Furthermore, some of the hydrogen may bond with oxygen bonded to a metal atom to generate electrons serving as carriers. Therefore, a transistor using an oxide semiconductor containing hydrogen is likely to have normally-on characteristics. For this reason, it is preferable to reduce the amount of hydrogen in the oxide semiconductor as much as possible. Specifically, the hydrogen concentration in an oxide semiconductor measured by SIMS is 1×10 20 atoms / cm 3 Less than 1 x 10 19 atoms / cm 3 less than 5 × 10 18 atoms / cm 3 less than 1×10 18 atoms / cm 3 Make it less than.

[0349] When an oxide semiconductor with sufficiently reduced impurities is used for a channel formation region of a transistor, stable electrical characteristics can be obtained.

[0350] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification.

[0351] (Fourth embodiment) In this embodiment, an electronic device including a display device according to one embodiment of the present invention will be described.

[0352] The display device of one embodiment of the present invention can be provided in various electronic devices, such as television devices, desktop or notebook computers, tablet computers, computer monitors, digital signage, large game machines such as pachinko machines, and other electronic devices with relatively large screens, as well as digital cameras, digital video cameras, digital photo frames, portable game machines, personal digital assistants, and sound players.

[0353] 22A, 22B, 23A, and 23B, examples of wearable devices that can be worn on the head will be described. These wearable devices have one or both of a function to display AR (Augmented Reality) content and a function to display VR (Virtual Reality) content. Note that these wearable devices may also have a function to display SR (Substitutional Reality) or MR (Mixed Reality) content in addition to AR and VR. When an electronic device has a function to display content such as AR, VR, SR, or MR, it is possible to enhance the sense of immersion felt by the user of the electronic device.

[0354] 22A and electronic device 700B shown in Fig. 22B each have a pair of display panels 751, a pair of housings 721, a communication unit (not shown), a pair of mounting units 723, a control unit (not shown), a sensor unit 725, a pair of optical members 753, a frame 757, and a pair of nose pads 758. Sensor unit 725 can be provided in housing 721, for example.

[0355] The display device of one embodiment of the present invention can be applied to the display panel 751. Therefore, the electronic device can display images with extremely high resolution.

[0356] Electronic device 700A and electronic device 700B can each project an image displayed on display panel 751 onto display area 756 of optical member 753. Because optical member 753 is translucent, the user can see the image displayed in the display area superimposed on a transmitted image visually recognized through optical member 753. Therefore, electronic device 700A and electronic device 700B are each electronic devices capable of AR display.

[0357] Electronic device 700A and electronic device 700B may be provided with a camera capable of capturing an image in front of them as an imaging unit. Furthermore, electronic device 700A and electronic device 700B may each be provided with an acceleration sensor such as a gyro sensor, thereby detecting the orientation of the user's head and displaying an image corresponding to that orientation in display area 756.

[0358] The communication unit has a wireless communication device, and can supply, for example, a video signal via the wireless communication device. Note that instead of or in addition to the wireless communication device, a connector to which a cable through which a video signal and a power supply potential can be connected may be provided.

[0359] Furthermore, the electronic device 700A and the electronic device 700B are provided with batteries, which can be charged wirelessly and / or by wire.

[0360] The sensor unit 725 has a function of detecting, for example, a touch on the outer surface of the housing 721. The sensor unit 725 can detect a tap operation, a slide operation, or the like by the user and execute various processes. For example, a tap operation can execute a process such as pausing or resuming a video, and a slide operation can execute a process such as fast-forwarding or fast-rewinding. Furthermore, providing the sensor unit 725 on each of the two housings 721 can widen the range of operations.

[0361] The display device of one embodiment of the present invention can be used as the sensor portion 725. Specifically, a light-receiving element that can be included in the display device of one embodiment of the present invention can be provided in the sensor portion 725. Furthermore, a light-receiving element can be manufactured in the sensor portion 725 by using the manufacturing method of the display device of one embodiment of the present invention. As a result, the sensor portion 725 can be a touch sensor including a light-receiving element with a high aperture ratio. Therefore, the sensor portion 725 can be a touch sensor with high detection sensitivity.

[0362] The electronic device 800A shown in FIG. 23A and the electronic device 800B shown in FIG. 23B each have a pair of display units 820, a housing 821, a communication unit 822, a pair of mounting units 823, a control unit 824, a pair of imaging units 825, and a pair of lenses 832.

[0363] The display device of one embodiment of the present invention can be applied to the display portion 820. Therefore, an electronic device capable of displaying images with extremely high resolution can be provided, which allows a user to feel a high sense of immersion.

[0364] Display unit 820 is provided inside housing 821 at a position that can be viewed through lens 832. Also, by displaying different images on the pair of display units 820, it is possible to perform a three-dimensional display using parallax.

[0365] Electronic device 800A and electronic device 800B can each be said to be electronic devices for VR. A user wearing electronic device 800A or electronic device 800B can view an image displayed on display unit 820 through lens 832.

[0366] It is preferable that electronic device 800A and electronic device 800B each have a mechanism that can adjust the left and right positions of lens 832 and display unit 820 so that they are optimally positioned according to the position of the user's eyes. It is also preferable that electronic device 800A and electronic device 800B each have a mechanism that can adjust the focus by changing the distance between lens 832 and display unit 820.

[0367] The user can wear the electronic device 800A or the electronic device 800B on the head by using the wearing unit 823. Note that, for example, in Fig. 23A, the wearing unit 823 is shaped like the temples of glasses (also called joints or temples), but is not limited to this. The wearing unit 823 may be shaped like a helmet or a band, for example, as long as it can be worn by the user.

[0368] The imaging unit 825 has a function of acquiring external information. Data acquired by the imaging unit 825 can be output to the display unit 820. The imaging unit 825 can be provided with a light-receiving element that can be included in the display device of one embodiment of the present invention. Furthermore, a light-receiving element can be manufactured in the imaging unit 825 by using the manufacturing method of the display device of one embodiment of the present invention. This allows the imaging unit 825 to be provided with a light-receiving element with a high aperture ratio, thereby enabling the imaging unit 825 to capture images with high sensitivity. Therefore, the imaging unit 825 can capture images with a high S / N ratio even under low illuminance, for example.

[0369] Although an example having the imaging unit 825 has been shown here, a distance measuring sensor (hereinafter also referred to as a detection unit) capable of measuring the distance to an object may be provided. That is, the imaging unit 825 is one aspect of the detection unit. As the detection unit, for example, an image sensor or a range image sensor such as a LIDAR (Light Detection and Ranging) can be used. By using an image obtained by the camera and an image obtained by the range image sensor, more information can be obtained, enabling more accurate gesture operations.

[0370] Electronic device 800A may have a vibration mechanism that functions as a bone conduction earphone. For example, a configuration having such a vibration mechanism can be applied to one or more of display unit 820, housing 821, and wearing unit 823. This allows a user to enjoy video and audio simply by wearing electronic device 800A, without the need for separate audio equipment such as headphones, earphones, or speakers.

[0371] The electronic device 800A and the electronic device 800B may each have an input terminal to which, for example, a cable for supplying a video signal from a video output device and power for charging a battery provided in the electronic device can be connected.

[0372] The electronic device of one embodiment of the present invention may have a function of wirelessly communicating with earphone 750. Earphone 750 has a communication unit (not shown) and has a wireless communication function. Earphone 750 can receive information (e.g., audio data) from the electronic device through the wireless communication function. For example, electronic device 700A shown in FIG. 22A has a function of transmitting information to earphone 750 through the wireless communication function. Furthermore, electronic device 800A shown in FIG. 23A has a function of transmitting information to earphone 750 through the wireless communication function.

[0373] 22B includes earphone unit 727. For example, earphone unit 727 and the control unit may be configured to be connected to each other by wire. Part of the wiring connecting earphone unit 727 and the control unit may be disposed inside housing 721 or wearing unit 723.

[0374] Similarly, electronic device 800B shown in Fig. 23B has earphone unit 827. For example, earphone unit 827 and control unit 824 can be configured to be connected to each other by wire. Part of the wiring connecting earphone unit 827 and control unit 824 may be disposed inside housing 821 or wearing unit 823. Furthermore, earphone unit 827 and wearing unit 823 may have magnets. This allows earphone unit 827 to be fixed to wearing unit 823 by magnetic force, which is preferable as it makes storage easier.

[0375] The electronic device may have an audio output terminal to which earphones or headphones can be connected. The electronic device may also have one or both of an audio input terminal and an audio input mechanism. For example, a sound collection device such as a microphone can be used as the audio input mechanism. By having the audio input mechanism, the electronic device may be endowed with the functionality of a so-called headset.

[0376] As described above, the electronic devices of one embodiment of the present invention are preferably either glasses-type devices (such as the electronic devices 700A and 700B) or goggle-type devices (such as the electronic devices 800A and 800B).

[0377] Furthermore, the electronic device of one embodiment of the present invention can transmit information to the earphone by wire or wirelessly.

[0378] 24A is a diagram showing an example of an oximeter 900. The oximeter 900 has a housing 911 and a light emitting and receiving device 912. A hollow portion is provided in the housing 911, and the light emitting and receiving device 912 is provided so as to be in contact with the wall surface of the hollow portion.

[0379] The light emitting and receiving device 912 functions as a light source that emits light and as a sensor that detects light. For example, when an object is placed in the hollow portion of the housing 911, the light emitting and receiving device 912 can detect the light that is emitted by the light emitting and receiving device 912, irradiated onto the object, and reflected from the object.

[0380] Here, the color of blood changes depending on the oxygen saturation of hemoglobin contained in the blood (the proportion of hemoglobin bound to oxygen). Therefore, when a finger is inserted into the hollow portion of the housing 911, the intensity of light reflected by the finger, detected by the light receiving and emitting device 912, changes. For example, the intensity of red light detected by the light receiving and emitting device 912 changes. As described above, the oximeter 900 can measure the oxygen saturation by detecting the intensity of the reflected light with the light receiving and emitting device 912. The oximeter 900 can be, for example, a pulse oximeter.

[0381] The display device of one embodiment of the present invention can be applied to the light-emitting and receiving device 912. In this case, the light-emitting and receiving device 912 includes at least a light-emitting element that emits red light (R). The light-emitting and receiving device 912 preferably includes a light-emitting element that emits infrared light (IR). The red light (R) reflectance of hemoglobin bound to oxygen is significantly different from the red light (R) reflectance of hemoglobin not bound to oxygen. On the other hand, the difference between the infrared light (IR) reflectance of hemoglobin bound to oxygen and the infrared light (IR) reflectance of hemoglobin not bound to oxygen is small. Therefore, when the light-emitting and receiving device 912 includes not only a light-emitting element that emits red light (R) but also a light-emitting element that emits infrared light (IR), the oximeter 900 can measure oxygen saturation with high accuracy.

[0382] When the display device of one embodiment of the present invention is used as the light-emitting and receiving device 912, the light-emitting and receiving device 912 preferably has flexibility. The flexibility of the light-emitting and receiving device 912 allows the light-emitting and receiving device 912 to have a curved shape. This allows light to be uniformly irradiated onto a finger, for example, and enables oxygen saturation to be measured with high accuracy, for example.

[0383] 24B is a diagram showing an example of a portable data terminal 9100. The portable data terminal 9100 includes a display unit 9110, a housing 9101, keys 9102, a speaker 9103, and the like. The portable data terminal 9100 may be, for example, a tablet. Here, keys such as the key 9102 may be keys for turning the power on and off, for example. That is, the keys such as the key 9102 may be, for example, power switches. Furthermore, the keys such as the key 9102 may be, for example, operation keys used to cause an electronic device to perform a desired operation.

[0384] The display unit 9110 can display information 9104, operation buttons (also referred to as operation icons or simply icons) 9105, and the like.

[0385] When the display device of one embodiment of the present invention is provided in the portable data terminal 9100, the display portion 9110 can function as a touch sensor or a near-touch sensor.

[0386] 24C is a diagram showing an example of a digital signage 9200. The digital signage 9200 can have a configuration in which a display unit 9210 is attached to a pillar 9201.

[0387] When the display device of one embodiment of the present invention is provided in the digital signage 9200, the display portion 9210 can function as a touch sensor or a near-touch sensor.

[0388] 24D is a diagram showing an example of a mobile information terminal 9300. The mobile information terminal 9300 includes a display portion 9310, a housing 9301, a speaker 9302, a camera 9303, keys 9304, a connection terminal 9305, and a connection terminal 9306. The mobile information terminal 9300 may be, for example, a smartphone. The connection terminal 9305 may be, for example, a microUSB, a lightning connector, or a Type-C connector. The connection terminal 9306 may be, for example, an earphone jack.

[0389] The display unit 9310 can display, for example, operation buttons 9307. The display unit 9310 can also display information 9308. Examples of the information 9308 include a display notifying an incoming email, SNS (social networking service), or phone call, the title of the email or SNS, the name of the sender of the email or SNS, the date and time, the remaining battery level, and signal strength.

[0390] When the display device of one embodiment of the present invention is provided in the portable information terminal 9300, the display portion 9310 can function as a touch sensor or a near-touch sensor.

[0391] 24E is a diagram showing an example of a wristwatch-type portable information terminal 9400. The portable information terminal 9400 includes a display portion 9410, a housing 9401, a wristband 9402, keys 9403, and a connection terminal 9404. Note that the connection terminal 9404 can be, for example, a microUSB, a lightning, or a Type-C, similar to the connection terminal 9305.

[0392] 24E shows an example in which the time is displayed on the display unit 9410 as the information 9406. In the example shown in FIG.

[0393] When the display device of one embodiment of the present invention is provided in the portable information terminal 9400, the display portion 9410 can function as a touch sensor or a near-touch sensor.

[0394] At least a part of the configuration examples exemplified in this embodiment and the corresponding drawings can be combined as appropriate with other configuration examples or drawings.

[0395] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification. [Explanation of symbols]

[0396] 10: display device, 10A: display device, 10B: display device, 20: pixel, 51: substrate, 52: finger, 53: layer, 55: layer, 57: layer, 59: substrate, 65: area, 67: fingerprint, 69: contact portion, 71: layer, 73: light-shielding layer, 75: light, 77: light, 80: light-receiving area, 81: light-receiving area, 100: display device, 100A: display device, 100B: display device, 100C: display device, 100D: display device, 100E: display device, 101: substrate, 125: protective layer, 130: connection portion, 131: insulating layer, 141: transistor, 141a: sacrificial film, 141b: sacrificial film, 142: transistor star, 143: space, 143a: protective film, 143b: protective film, 145a: resist mask, 145b: resist mask, 146: filter, 147a: sacrificial layer, 147b: sacrificial layer, 147c: sacrificial layer, 147d: sacrificial layer, 148: light-shielding layer, 149a: protective layer, 149b: protective layer, 151: substrate, 152: substrate, 153: substrate, 154: substrate, 155: adhesive layer, 156: adhesive layer, 158: insulating layer, 162: display unit, 164: circuit, 165: wiring, 166: conductive layer, 172: FPC, 173: IC, 201: transistor, 204: connecting portion, 211: insulating layer , 212: insulating layer, 213: insulating layer, 214: insulating layer, 215: insulating layer, 221: conductive layer, 222a: conductive layer, 222b: conductive layer, 223: conductive layer, 228: region, 231: semiconductor layer, 240: capacitance, 241: conductive layer, 242: adhesive layer, 243: insulating layer, 244: connection layer, 245: conductive layer, 251: conductive layer, 252: conductive layer, 254: insulating layer, 255: insulating layer, 256: plug, 261: insulating layer, 262: insulating layer, 263: insulating layer, 264: insulating layer, 265: insulating layer, 271: plug, 274: plug, 274a: conductive layer, 274b: conductive layer, 301: Substrate, 310: transistor, 311: conductive layer, 312: low resistance region, 313: insulating layer, 314: insulating layer, 315: element isolation layer, 320: transistor, 321: semiconductor layer, 323: insulating layer, 324: conductive layer, 325: conductive layer, 326: insulating layer, 327: conductive layer, 328: insulating layer, 329: insulating layer, 331: substrate, 332: insulating layer, 419: resin layer, 420: substrate, 501: electrode, 501B: electrode, 501C: connection electrode, 501G: electrode, 501IR: electrode, 501PD: electrode, 501R: electrode, 502: electrode, 503: region, 512: light emitting unit,512B: light-emitting unit, 512B_1: light-emitting unit, 512B_2: light-emitting unit, 512B_3: light-emitting unit, 512G: light-emitting unit, 512G_1: light-emitting unit, 512G_2: light-emitting unit, 512G_3: light-emitting unit, 512Gf_1: layer, 512Gf_2: layer, 512IR_1: light-emitting unit, 512IR_2: light-emitting unit, 512R: light-emitting unit, 512R_1: light-emitting unit, 512R_2: light-emitting unit, 512R_3: light-emitting unit, 512Rf_1: layer, 512Rf_2: layer, 521: layer, 522: layer, 523: light-emitting unit optical layer, 523B: light-emitting layer, 523G: light-emitting layer, 523R: light-emitting layer, 524: layer, 525: layer, 525B: layer, 525G: layer, 525Gf: film, 525IR: layer, 525R: layer, 525Rf: film, 531: intermediate layer, 531B: intermediate layer, 531G: intermediate layer, 531Gf: intermediate film, 531IR: intermediate layer, 531PD: intermediate layer, 531R: intermediate layer, 531Rf: intermediate film, 541: insulating layer, 542: light-receiving unit, 542_1: light-receiving unit, 542_2: light-receiving unit, 543: light-receiving layer, 544: insulating layer, 550: light-emitting element, 550B: light-emitting element, 550G: light-emitting element element, 550IR: light-emitting element, 550R: light-emitting element, 560: light-receiving element, 560L: light-receiving element, 700A: electronic device, 700B: electronic device, 721: housing, 723: wearing part, 725: sensor part, 727: earphone part, 750: earphone, 751: display panel, 753: optical member, 756: display area, 757: frame, 758: nose pad, 800A: electronic device, 800B: electronic device, 820: display part, 821: housing, 822: communication part, 823: wearing part, 824: control part, 825: imaging part, 827: earphone part, 832: lens, 900: oximeter ,911: Housing, 912: Light emitting / receiving device, 9100: Portable data terminal, 9101: Housing, 9102: Key, 9103: Speaker, 9104: Information, 9110: Display unit, 9200: Digital signage, 9201: Pillar, 9210: Display unit, 9300: Portable information terminal, 9301: Housing, 9302: Speaker, 9303: Camera, 9304: Key, 9305: Connection terminal, 9306: Connection terminal, 9307: Operation button, 9308: Information, 9310: Display unit, 9400: Portable information terminal, 9401: Housing, 9402: Wristband, 9403: Key, 9404: Connection terminal,9406: Information, 9407: Operation buttons, 9410: Display unit,

Claims

[Claim 1] A light emitting element and a light receiving element are included, the light-emitting element has a first pixel electrode, a first light-emitting layer on the first pixel electrode, an intermediate layer on the first light-emitting layer, a second light-emitting layer on the intermediate layer, a common layer on the second light-emitting layer, and a common electrode on the common layer; the light receiving element has a second pixel electrode, a light receiving layer on the second pixel electrode, the common layer on the light receiving layer, and the common electrode on the common layer; the common layer functions as either a hole injection layer or an electron injection layer in the light-emitting element, the common layer functions as either a hole transport layer or an electron transport layer in the light-receiving element, a first transistor and a second transistor are provided; one of a source and a drain of the first transistor is electrically connected to the first pixel electrode; one of a source and a drain of the second transistor is electrically connected to the second pixel electrode; A display device in which the first transistor and the second transistor each have a channel formation region made of silicon or metal oxide.

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