Imaging apparatus and display device

Abstract

To reduce an optical detection device in size, and reduce a manufacturing cost.SOLUTION: In order to reduce an area when a visible light sensor and an infrared light sensor are arranged, an imaging apparatus is constructed so that a first photodiode for detecting a visible light and a second photodiode for detecting an infrared light are overlapped and arranged, and the visible light is sucked by a tip of the first photodiode, and the visible light entered into the second photodiode is extremely reduced. Also, the first photodiode that is overlapped and arranged with the second photodiode is used as an optical filter of the second photodiode. Therefore, a semiconductor layer constructing the first photodiode sucks the visible light, and is a semiconductor layer that penetrates the infrared light, and a semiconductor layer of the second photodiode sucks the infrared light.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a light detection device, a display device including the light detection device, and a display device including the light detection device. Regarding electronic devices. [Background technology]

[0002] In recent years, devices equipped with circuits for detecting light (also called "photodetection devices") have been used as pixel circuits for display devices. For example, in Patent Document 1, a touch panel that is integrated with a display panel is The optical sensor element detects the intensity of visible light (hereinafter referred to as the visible light sensor) and the optical sensor element detects the intensity of infrared light (hereinafter referred to as the infrared sensor). The document discloses a liquid crystal display device in which optical sensor elements (hereinafter referred to as infrared optical sensors) are arranged side by side.

[0003] In the configuration of Patent Document 1, a visible light sensor and an infrared light sensor are arranged side by side to achieve high accuracy. This configuration realizes touch panel function. Even if the detection accuracy of the visible light sensor is reduced due to external light noise, the visible light sensor can still be used The sensor detects infrared light that is not affected by visible light by using an infrared sensor with different light receiving sensitivity. This enables accurate position detection even under a wide range of environmental illumination. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2010 / 084640 Brochure Summary of the Invention [Problem to be solved by the invention]

[0005] As shown in Patent Document 1, a visible light sensor and an infrared light sensor are arranged side by side in a display panel. In the case of a 3.1-inch LCD, the area of ​​the display where each sensor is placed becomes larger, and the pixel size becomes larger. In addition, when an infrared light sensor is used as shown in Patent Document 1, the visible light to the infrared light sensor In order to reduce noise caused by the incidence of light, an optical filter must be installed, which increases manufacturing costs. This can also be a contributing factor.

[0006] One aspect of the present invention is a light detection device including a visible light sensor and an infrared light sensor arranged in parallel. In this case, the area occupied by each sensor is reduced by sharing the area when placing each sensor. An object of the present invention is to provide a photodetector device capable of reducing the pixel size. Another aspect of the present invention is an optical filter for reducing the incidence of visible light when an infrared light sensor is used. One object is to reduce manufacturing costs by not providing a filter. [Means for solving the problem]

[0007] One aspect of the present invention is to reduce the area required for arranging a visible light sensor and an infrared light sensor. a first photodiode for detecting visible light and a second photodiode for detecting infrared light. The first photodiode is arranged to overlap with the second photodiode, and visible light is absorbed first by the first photodiode. This greatly reduces the amount of visible light incident on the second photodiode. In one embodiment, the first photodiode is arranged so as to overlap the second photodiode. The first photodiode is used as an optical filter. The semiconductor layer constituting the electrode is a semiconductor layer that absorbs visible light and transmits infrared light. The semiconductor layer of the photodiode is a semiconductor layer that absorbs infrared light.

[0008] One aspect of the present invention is a photodiode for detecting visible light, a photodiode for detecting infrared light, and a photodiode for detecting infrared light. The second photodiode detects the accumulated current depending on the photocurrent in the first photodiode. a first amplifier circuit for amplifying and outputting the charge, and a photocurrent at a second photodiode A second amplifier circuit is provided for amplifying and outputting the charge accumulated according to the first frame. The semiconductor layer of the first photodiode is made of amorphous silicon, and the semiconductor layer of the second photodiode is made of The body layer is made of crystalline silicon and includes a first photodiode and a second photodiode. However, the first photodiode is located on the side where the incident light including visible light and infrared light is incident. The first photodiode absorbs visible light from the incident light. The second photodiode detects the first photodiode from the incident light and transmits infrared light. It is a photodetector that absorbs transmitted infrared light.

[0009] In one embodiment of the present invention, the semiconductor layer of the second photodiode includes a first amplifier circuit and The photodetector is a semiconductor layer provided in the same layer as the semiconductor layer of the transistor of the amplifier circuit of 2. The device may be an output device.

[0010] In one embodiment of the present invention, the semiconductor layer of the first photodiode includes a p-type semiconductor region, an i-type A semiconductor region and an n-type semiconductor region, The photodetector may have a first photodiode formed by stacking regions.

[0011] In one embodiment of the present invention, the second photodiode has a p-type semiconductor region, an i-type semiconductor region, and a first photodiode having an n-type semiconductor region and overlapping the second photodiode. The area in which the i-type semiconductor region of the second photodiode is provided is Larger photodetectors are also possible.

[0012] In one embodiment of the present invention, the first amplifier circuit and the second amplifier circuit each include a first transistor. a first transistor, a second transistor, and a third transistor, The second transistor and the third transistor are electrically connected in series between the power supply line and the output signal line. The gate of the first transistor is electrically connected to the first terminal of the first transistor. The second terminal of the photodiode is electrically connected to one electrode of the photodetector. Good too. Effect of the Invention

[0013] According to one aspect of the present invention, a light detection device is provided in which a visible light sensor and an infrared light sensor are arranged side by side. In the device, the area required for arranging each sensor is shared, reducing the area required for each sensor. It is possible to provide a photodetector device that can be reduced in size. The area can also be increased, improving the sensitivity of each sensor to visible and infrared light. In addition, in one embodiment of the present invention, when an infrared light sensor is used, the incident visible light can be detected. This makes it possible to reduce the number of optical filters required for reducing the noise, thereby enabling the reduction of manufacturing costs. do. [Brief description of the drawings]

[0014] [Figure 1] 1A and 1B are a circuit diagram and a top view of one embodiment of the present invention. [Diagram 2] FIG. 1 is a cross-sectional view of one embodiment of the present invention. [Diagram 3] FIG. 1 is a cross-sectional view of one embodiment of the present invention. [Figure 4]1A and 1B are a circuit diagram and a timing chart according to one embodiment of the present invention. [Diagram 5] FIG. 1 is a circuit diagram according to one embodiment of the present invention. [Figure 6] 11A to 11C are diagrams illustrating electronic devices according to embodiment 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, the embodiment of the present invention will be described with reference to the drawings. It is to be understood that the invention can be practiced in various different ways without departing from the spirit and scope of the invention. It will be readily understood by those skilled in the art that various modifications may be made to the form and details of the present invention. The present invention should not be construed as being limited to the description of the present embodiment. In the configuration of the present invention, reference numerals indicating the same objects are common among different drawings.

[0016] The size, layer thickness, and signal waveform of each component shown in the drawings of each embodiment may differ from those shown in the drawings. may be exaggerated for clarity and are not necessarily to scale. Not limited to.

[0017] In this specification, the terms first, second, third, through Nth (N is a natural number) refer to configurations. It is noted that this is added to avoid confusion of elements and is not intended to limit the number. do.

[0018] (Embodiment 1) In this embodiment, a structure and an operation of a photodetector will be described with reference to FIGS. do.

[0019] The configuration of the photodetector will be described with reference to FIG. a first photodiode 102A, a second photodiode 102B, a first amplifier circuit 103A, and It has a second amplifier circuit 103B.

[0020] The first photodiode 102A detects visible light and infrared light incident from the outside. It is a semiconductor element for detecting light. Specifically, the semiconductor of the first photodiode 102A is The body layer is made up of a p-type semiconductor region, an i-type semiconductor region, and an n-type semiconductor region having amorphous silicon. The semiconductor layer of the first photodiode 102A is an i-type semiconductor region. Alternatively, the insulating layer 11 may be formed by laminating a p-type semiconductor region and an n-type semiconductor region without providing the insulating layer 11 . Amorphous silicon absorbs visible light incident from the outside, and It has the property of transmitting incident infrared light.

[0021] A photodiode is a device that generates a photocurrent according to the intensity of external light. Since all that is required is a photoelectric conversion element, it is sometimes called a photoelectric conversion element.

[0022] In this specification, the i-type semiconductor region refers to a semiconductor region that is imparted with p-type or n-type. The impurity is 1×10 20 cm -3 The oxygen and nitrogen concentrations are less than 5×10 19 cm -3 This refers to a semiconductor region in which the photoconductivity is 100 times or more higher than the dark conductivity. In addition, the i-type semiconductor region contains boron (B) at a concentration of 10 ppm or more and 1000 ppm or less. The following may also be added:

[0023] The second photodiode 102B detects infrared light out of visible light and infrared light incident from the outside. It is a semiconductor element for detecting light. Specifically, the semiconductor of the second photodiode 102B The body layer is made up of a p-type semiconductor region, an i-type semiconductor region, and an n-type semiconductor region having crystalline silicon. The semiconductor layer of the second photodiode 102B is an i-type semiconductor region. Alternatively, the insulating layer 11 may be formed by laminating a p-type semiconductor region and an n-type semiconductor region without providing the insulating layer 11 . Compared to amorphous silicon, crystalline silicon has the property of absorbing infrared light and visible light.

[0024] It is effective to configure the second photodiode 102B as a lateral junction photodiode. With this configuration, the second photodiode 102B and the second transistor A first transistor 105A, a second transistor 105B, a third transistor 106A, and a third transistor Therefore, the photodetector 101 can be fabricated simultaneously with the phototransistor 106B. Specifically, the second photodiode 102B and the second transistor 1 05A, a second transistor 105B, a third transistor 106A, and a third transistor The formation of the semiconductor layer constituting the photodiode 106B and the formation of the impurity region can be performed simultaneously. Cut.

[0025] The first amplifier circuit 103A amplifies light incident on the first photodiode 102A from the outside. In particular, it amplifies the charge accumulated in response to the photocurrent generated by visible light and outputs it as an electrical signal. Specifically, the charge stored in response to the photocurrent is amplified by the first amplifier circuit 103. The reset operation, storage operation, and selection operation performed by the multiple transistors of A The signal is converted into an amplified electrical signal and output to the outside.

[0026] The first amplifier circuit 103A includes a first transistor 104A (also called a transfer transistor). , the second transistor 105A (also called an amplifying transistor) and the third transistor 1 06A (also called a selection transistor). The first amplifier circuit 103A is connected to a transfer control line 107 (also called a first wiring) and a power supply line 108 (a second wiring). 2), a selection control line 109 (also called a third line), a first output signal line 11 0A (also called the fourth wiring) and the reset control line 111 (also called the fifth wiring) It will be controlled.

[0027] One electrode of the first photodiode 102A is connected to a reset control line 111. The other electrode of the first photodiode 102A is connected to a first terminal of the first transistor 104A. The gate of the first transistor 104A is connected to a transfer control line 107. The second terminal of the first transistor 104A is connected to the gate of the second transistor 105A. The first terminal of the second transistor 105A is connected to the power supply line 108. The second terminal of the second transistor 105A is connected to the first terminal of the third transistor 106A. The gate of the third transistor 106A is connected to the selection control line 109. The second terminal of the transistor 106A is connected to a first output signal line 110A.

[0028] In this specification, "A and B are connected" does not mean that A and B are directly connected. In addition to those that are electrically connected, A and B are also included. "Connected to" means that there is an object between A and B that has some electrical effect. This represents the case where the part between A and B that contains the object becomes a node.

[0029] Specifically, A and B are connected via a switching element such as a transistor. When the switching element is turned on, A and B become approximately the same potential, or when the resistance element is turned on, A and B are connected via a resistor, and the potential difference generated across the resistor is When considering the circuit operation, for example, when the voltage between A and B is low enough that it does not affect the operation of This represents a case where it is acceptable to regard the parts as the same node.

[0030] A transistor has at least three terminals including a gate, a drain, and a source. A channel region is provided between a drain region and a source region. A current can be passed through the source region, the channel region, and the source region. Which is the source and which is the drain depends on the transistor structure and operating conditions. It is difficult to determine whether the source is a drain or a drain. The regions that function as a source and a drain may not be referred to as a source or a drain. In that case, for example, they may be referred to as the first terminal and the second terminal, respectively. These may be referred to as a first electrode and a second electrode, respectively. It may be referred to as a drain region.

[0031] The first transistor 104A is connected to the first photodiode 104 by a signal on the transfer control line 107. The charge accumulated by the photocurrent generated by the incidence of visible light on the diode 102A is transferred to the second This is a transistor for transferring the signal to the gate of the transistor 105A. The first photodiode 102A is illuminated with visible light, generating a pixel pixel 105A. The gate potential is proportional to the charge accumulated by the photocurrent. (First terminal) A transistor that amplifies the current flowing between the third transistor and the 106A is connected to the source and drain of the second transistor 105A by a signal on the selection control line 109. The current flowing between the power supply line 108 and the first output signal line 110A flows between the power supply line 108 and the first output signal line 110A. This is a transistor for controlling this.

[0032] The second amplifier circuit 103B, like the first amplifier circuit 103A, includes a second photodiode The electric current accumulated in response to the photocurrent generated by the light, especially infrared light, incident on 102B from the outside is It is a circuit that amplifies the charge and outputs it as an electrical signal. The electric charge is stored in the second amplifier circuit 103B through a plurality of capacitors, similar to the first amplifier circuit 103A. The reset, storage, and selection operations performed by the transistors produce an amplified electrical signal. The signal is converted into a signal and output to the outside.

[0033] The second amplifier circuit 103B includes a first transistor 104B (also called a transfer transistor). , the second transistor 105B (also called an amplifying transistor) and the third transistor 1 06B (also called a selection transistor). The second amplifier circuit 103B is connected to a transfer control line 107, a power supply line 108, a selection control line 109, and a second The output signal line 110B (also called the sixth wiring) and the reset control line 111 are used to control the This will be the case.

[0034] The transfer control line 107, the power supply line 108, and the selection control line 109 are connected to the second amplifier circuit 103B. The reset control line 109 and the reset control line 111 are different from the wirings connected to the first amplifier circuit 103A. Each of the wirings connected to the second amplifier circuit 103B may be the wirings connected to the first amplifier circuit 103B. By using wiring different from each wiring connected to the first amplifier circuit 103A, The control of the amplifier circuit 103B can be performed at a different timing.

[0035] One electrode of the second photodiode 102B is connected to a reset control line 111. The other electrode of the second photodiode 102B is connected to the first terminal of the first transistor 104B. The gate of the first transistor 104B is connected to a transfer control line 107. The second terminal of the first transistor 104B is connected to the gate of the second transistor 105B. The first terminal of the second transistor 105B is connected to the power supply line 108. The second terminal of the second transistor 105B is connected to the first terminal of the third transistor 106B. The gate of the third transistor 106B is connected to the selection control line 109. The second terminal of the transistor 106B is connected to a second output signal line 110B.

[0036] The first transistor 104B is connected to the second photodiode 104B by a signal on the transfer control line 107. The charge stored in the second electrode 102B due to the photocurrent generated by the incidence of infrared light thereon is transferred to the second electrode 102B. This is a transistor for transferring the signal to the gate of the transistor 105B. The second photodiode 102B is illuminated with infrared light, generating a second photodiode 105B. The gate potential is proportional to the charge accumulated by the photocurrent. (First terminal) A transistor that amplifies the current flowing between the third transistor and the 106B is connected to the source and drain of the second transistor 105B by a signal on the selection control line 109. The current flowing between the power supply line 108 and the second output signal line 110B is This is a transistor for controlling this.

[0037] FIG. 1B is a top view of the photodetector 101 shown in FIG. 1A according to one embodiment of the present invention. In FIG. 1B, a first photodiode 102A and a second photodiode 102B are shown in the same manner as in FIG. 1A. A photodiode 102B, a first transistor 104A constituting a first amplifier circuit, The first transistor 105A and the second transistor 106A constitute a second amplifier circuit. A first transistor 104B, a second transistor 105B, and a third transistor 1B shows the transfer control line 107, A power supply line 108, a selection control line 109, a first output signal line 110A, and a second output signal line 110 B, Reset control line 111 is shown.

[0038] In addition, the top view shown in FIG. 1(B) illustrates the arrangement of each element formed of wiring and semiconductor layers. For the sake of clarity, the insulating layers are not shown, but insulating layers or the like are provided between the conductive layers as appropriate. Connections between the wires are made through openings in the insulating layer.

[0039] The first photodiode 102A of the present embodiment shown in FIG. Specifically, the first photodiode 102A is provided on the first photodiode 102B. The second photodiode 102B includes a p-type semiconductor region, an i-type semiconductor region, and an n-type semiconductor region. It is preferably provided on the conductor region. The photodiode 102A is at least the i-type semiconductor region of the second photodiode 102B. The configuration is such that the sensor is provided on an area that will become a target area.

[0040] By adopting the configuration of FIG. 1B, the first photodiode 102, which is a visible light sensor, A photodiode 102A serving as an infrared light sensor and a second photodiode 102B serving as an infrared light sensor are arranged in parallel. In detection devices, the area required for each sensor is shared, reducing the area required. As a result, the area required for arranging each sensor can be reduced, resulting in a smaller pixel size. Therefore, it is possible to provide a photodetector device that can reduce the size of each sensor. The area of ​​the sensor can be increased, improving the sensitivity of each sensor to visible and infrared light. It can be raised.

[0041] The semiconductor layer of the first photodiode 102A, which is a visible light sensor, is made of amorphous silicon. The lens has the characteristic of absorbing visible light incident from the outside and transmitting infrared light incident from the outside. As a result, by adopting the configuration shown in FIG. 1B, the second photodiode, which is an infrared light sensor, Therefore, the incidence of visible light on the electrode 102B can be reduced. In the case of the second photodiode 102B configured to detect infrared light as the active layer, the infrared light An optical filter for reducing noise during detection is provided on the second photodiode 102B. Since there is no need to use a separate electrode, the manufacturing cost can be reduced.

[0042] Next, in FIG. 2(A), the dashed lines A1-A2 and A3-A4 in the top view shown in FIG. 1(B) are 2(B) is a cross-sectional view corresponding to the dashed line B1-B2 in the top view shown in FIG. 1(B). Shows.

[0043] 2A will be described. In the cross-sectional view shown in FIG. 2A, A light-shielding layer 201 and an undercoat film 202 are provided. The p-type semiconductor region 203 and the i-type semiconductor region 204 in the second photodiode 102B are The p-type semiconductor region 203 and the p-type semiconductor region 204 in the second photodiode 102B are provided. The second transistor 105B is formed in the same layer as the semiconductor layer constituting the i-type semiconductor region 204. The n-type semiconductor region 205 and the i-type semiconductor region 206 that constitute the semiconductor layer are provided. Similarly, the p-type semiconductor region 203 and the i-type semiconductor region The semiconductor layer of the third transistor 106B is formed in the same layer as the semiconductor layer forming 204. An n-type semiconductor region 207 and an i-type semiconductor region 208 are provided corresponding to the n-type semiconductor region 207 and the i-type semiconductor region 208. The p-type semiconductor region 203 and the i-type semiconductor region 204 in the diode 102B are formed In the same layer as the semiconductor layer, an n-type semiconductor region constituting the semiconductor layer of the first transistor 104A is provided. An area 209 is provided.

[0044] The transparent substrate 200 is a substrate made of a material that is transparent to visible light and infrared light. For example, a plastic substrate having transparency to visible light and infrared light, a visible A glass substrate that is transmissive to light and infrared light can be used.

[0045] The light-shielding layer 201 is formed to prevent infrared light and visible light from the backlight from reaching the first photodiode 1. 102A and the second photodiode 102B. The light-shielding layer 201 is made of a metal material such as aluminum or chromium that can block infrared light and visible light. The film is formed by sputtering, CVD or coating using The light-shielding layer 201 is formed by processing using a lithography method and an etching method. Not only the region where the photodiode 102B is laminated, but also the first amplifier circuit 103A and the second It may also be provided in an area laminated with the semiconductor layers of the transistors constituting the amplifier circuit 103B. The light-shielding film blocks the semiconductor layer of each transistor from light, preventing light from entering the backlight. The incidence of infrared and visible light from these sources causes deterioration of characteristics such as a shift in the threshold voltage of transistors. The backlight is configured as a light-transmitting Any configuration may be used as long as a light source capable of emitting infrared light and visible light from the substrate 200 side is used. Specifically, the backlight is composed of a light emitting diode that emits infrared light and a light emitting diode that emits visible light. The light emitting diodes may be arranged side by side.

[0046] Here, the backlight is a first photodiode that detects visible light and infrared light. The light-transmitting substrate 200 is provided so that the light is incident on the first photodiode 102A and the second photodiode 102B. The infrared light may be separately emitted from the opposing substrate side.

[0047] The undercoat film 202 is made of alkali metals such as Na and alkaline earth metals contained in the light-transmitting substrate 200. This prevents metalloids from diffusing into the second photodiode 102B and adversely affecting its characteristics. The base film 202 is formed by depositing silicon oxide, silicon nitride, or A single layer or a multilayer of a material having light transmitting and insulating properties such as silicon oxynitride or silicon nitride oxide is used. The surface of the base film 202 is a semiconductor layer of the second photodiode 102B. When forming the layers, it is preferable that they are formed so as to improve flatness.

[0048] The semiconductor layer of the second photodiode 102B is made of crystalline silicon such as polycrystalline silicon. A second photodiode made of a semiconductor layer having crystalline silicon can be used. The electrode 102B includes a p-type semiconductor region 203, an i-type semiconductor region 204, and an n-type semiconductor region ( (not shown) are provided in the horizontal direction on the light-transmitting substrate 200. The semiconductor layers of the transistors constituting the second amplifier circuit 103B are also made of a crystalline silicon or the like. The n-type semiconductor region 207, the i-type semiconductor region 208, and the n-type semiconductor region 209 are formed by using crystalline silicon. 209 is provided. The semiconductor layers of the second photodiode 102B and each transistor are The formed crystalline silicon film is processed using photolithography and etching, and then After forming a mask by photolithography, p-type or n-type impurity regions are formed. The formation is performed by ion implantation or ion doping.

[0049] The semiconductor layer of the second photodiode 102B is made of single crystal silicon by the bonding and peeling method. First, a semiconductor wafer such as a silicon wafer is , hydrogen ion (H + , H2 + , H3 + etc.) or hydrogen and helium ions are added The semiconductor wafer is bonded onto the base film 202, forming an embrittlement layer in the semiconductor wafer. Then, the semiconductor layer is formed on the base film 202 by peeling off the embrittlement layer by heat treatment. The depth from the surface of the wafer to the embrittlement layer corresponds to the thickness of the semiconductor layer, so the addition of hydrogen ions, etc. By controlling the conditions, the thickness of the semiconductor layer can be adjusted.

[0050] In the cross-sectional view shown in FIG. 2A, the semiconductor layer of the second photodiode 102B , the semiconductor layer of the second transistor 105B, the semiconductor layer of the third transistor 106B, and An insulating layer 210 is provided on the semiconductor layer of the first transistor 104A. On the i-type semiconductor region 206 through the line 0, a transfer control line 107, a power supply line 108, and a selection control line A gate electrode 211 is provided, which is formed in the same layer as the line 109. On the semiconductor region 208, the transfer control line 107, the power supply line 108, and the selection control line 109 are formed in the same layer. On the insulating layer 210, a gate electrode 212 is formed. A power supply line 108 is provided, which is formed in the same layer as the selection control line 109 .

[0051] In addition, the insulating layer 210 is formed by adding an alkali metal such as Na or an alkaline earth metal from the outside to the second phosphide. The insulating layer 210 prevents the diffusion of the semiconductor into the photodiode 102B and adversely affecting its characteristics. Using plasma CVD and sputtering methods, silicon oxide films, silicon oxynitride films, etc. A single layer of a material having light transmitting and insulating properties, such as a silicon nitride oxide film or an organic resin film, is used. It is formed by laminating.

[0052] The various wirings formed in the same layer as the gate electrode 211 and the gate electrode 212 have electrical conductivity. The conductive metal material may be molybdenum, Titanium, Chromium, Tantalum, Tungsten, Aluminum, Copper, Neodymium, Scandium It is formed in a single layer or multilayer using metal materials such as these, or alloy materials that contain these as the main components. The film is formed by sputtering or vacuum deposition.

[0053] In the cross-sectional view shown in FIG. 2(A), an insulating layer 210, a gate electrode 211, and a gate electrode 21 An insulating layer 213 is provided on the insulating layer 210 and the power line 108. A first output signal line is provided between the n-type semiconductor region 205 and the n-type semiconductor region 207 via the 110A, a conductive layer formed in the same layer as the second output signal line 110B, and the reset control line 111 On the n-type semiconductor region 207 via the insulating layer 210 and the insulating layer 213, The second output signal line 110A is formed in the same layer as the first output signal line 110A and the reset control line 111. The insulating layer 210 and the n-type semiconductor region 20 are provided with the insulating layer 213 interposed therebetween. Between the power supply line 108 and the first output signal line 110A and the second output signal line 110B A conductive layer 215 is provided in the same layer as the reset control line 111. A first output signal line 110A and a second output signal line 110B are disposed on the p-type semiconductor region 203 via the insulating layer 213. A conductive layer 216 is provided which is formed in the same layer as the output signal line 110B and the reset control line 111. A first output is provided on the n-type semiconductor region 209 via the insulating layer 210 and the insulating layer 213. The signal line 110A, the second output signal line 110B, and the reset control line 111 are formed in the same layer. A conductive layer 217 is provided.

[0054] The insulating layer 213 is a silicon oxide film formed by using a plasma CVD method, a sputtering method, or the like. Silicon oxynitride film, silicon nitride oxide film, organic resin film, etc. The material having the above structure is formed as a single layer or a laminate.

[0055] The conductive layers 214 to 217 are formed by a sputtering method or a vacuum deposition method. Lithium, titanium, chromium, tantalum, tungsten, aluminum, copper, yttrium Metals such as these, alloy materials mainly composed of these, or conductive materials such as indium oxide A material such as a metal oxide is formed in a single layer or a multilayer structure.

[0056] In the cross-sectional view shown in FIG. 2A, the first photoresist is formed on the insulating layer 213 and the conductive layer 216. The p-type semiconductor region 218, the i-type semiconductor region 219, and the n-type semiconductor region 220 in the diode 102A. A conductor region 220 is provided. Note that the p-type semiconductor in the first photodiode 102A Region 218 is provided by laminating it with the conductive layer 216 so that its end portion overlaps it.

[0057] The semiconductor layer of the first photodiode 102A may be made of amorphous silicon. The first photodiode 102A, which is made of a semiconductor layer having amorphous silicon, The p-type semiconductor region 218, the i-type semiconductor region 219, and the n-type semiconductor region 220 are disposed on the light-transmitting substrate 2. 00 and are stacked vertically.

[0058] The p-type semiconductor region 218 is formed of amorphous silicon containing an impurity element that imparts p-type conductivity. The p-type semiconductor region 218 is formed by using an impurity element of Group 13 (e.g., boron (B)). The semiconductor material gas is used to form the film by the plasma CVD method. Or, Si2H6, SiH2Cl2, SiHCl3 Alternatively, SiCl4, SiF4, etc. may be used. The thickness of the p-type semiconductor region 218 is 10 nm or more. It is preferable to form it so that the thickness is 50 nm or less.

[0059] The i-type semiconductor region 219 is made of amorphous silicon. The semiconductor material gas is used to form amorphous silicon by the plasma CVD method. Silane (SiH4) may be used as the conductive material gas. Alternatively, Si2H6, Si H2Cl2, SiHCl3, SiCl4, SiF4, etc. may also be used. i-type semiconductor region 2 The film thickness of 19 is preferably formed to be 200 nm or more and 1000 nm or less.

[0060] The n-type semiconductor region 220 is formed of amorphous silicon containing an impurity element that imparts n-type conductivity. The n-type semiconductor region 220 is formed by using an impurity element of Group 15 (e.g., phosphorus (P)). The semiconductor material gas is used to form the film by the plasma CVD method. Or, Si2H6, SiH2Cl2, SiHCl3 Alternatively, SiCl4, SiF4, etc. may be used. The thickness of the n-type semiconductor region 220 is 20 nm or more. It is preferable to form it so that the thickness is 200 nm or less.

[0061] In the cross-sectional view shown in FIG. 2A, the first photodiode 102A and the second output signal On the line 110B, the conductive layer 214, the conductive layer 215, the conductive layer 216, and the conductive layer 217, an insulating The n-type semiconductor region 220 and the conductive layer 217 are provided with the insulating layer 221 interposed therebetween. A conductive layer 222 formed in the same layer as the conductive layer that serves as the pixel electrode is provided between them.

[0062] The insulating layer 221 is a silicon oxide film formed by using a plasma CVD method, a sputtering method, or the like. Silicon oxynitride film, silicon nitride oxide film, organic resin film, etc. The insulating layer 221 is formed by using a single layer or a stacked layer of a material having a flat surface. It is preferable to form an insulating layer.

[0063] The conductive layer 222 may be a light-transmitting conductive layer. Indium Tin Oxide, Indium Tin Oxide with Silicon Oxide, Indium Oxide It is formed using a material such as indium zinc oxide.

[0064] Next, FIG. 2B will be described. In the cross-sectional view shown in FIG. 2B, a light-transmitting substrate 200 A light-shielding layer 201 and an undercoat film 202 are provided on the light-shielding layer 201. 1, a p-type semiconductor region 203 of the second photodiode 102B, an i-type semiconductor A region 204 and an n-type semiconductor region 223 are provided.

[0065] In the cross-sectional view shown in FIG. 2B, the semiconductor layer of the second photodiode 102B An insulating layer 210 is provided on the insulating layer 210. The transfer control line 107 and the selection control A power supply line 108 is provided, which is formed in the same layer as the power supply line 109 .

[0066] In the cross-sectional view shown in FIG. 2B, the insulating layer 21 is formed on the insulating layer 210 and the power line 108. On the p-type semiconductor region 203 via the insulating layer 210 and the insulating layer 213, The first output signal line 110A, the second output signal line 110B, and the reset control line 111 are arranged in the same layer. A conductive layer 216 is formed on the insulating layer 210 and the insulating layer 213. On the body region 223, a first output signal line 110A, a second output signal line 110B, a reset A conductive layer 224 formed in the same layer as the control line 111 is provided.

[0067] In the cross-sectional view shown in FIG. 2B, the first photoresist is formed on the insulating layer 213 and the conductive layer 216. The p-type semiconductor region 218, the i-type semiconductor region 219, and the n-type semiconductor region 220 in the diode 102A. A conductor region 220 is provided. Note that the p-type semiconductor in the first photodiode 102A Region 218 is provided by laminating it with the conductive layer 216 so that its end portion overlaps it.

[0068] In the cross-sectional view shown in FIG. 2B, the first photodiode 102A, the conductive layer 216, On the conductive layer 224, an insulating layer 221 is provided.

[0069] Next, in FIG. 3(A), in the cross-sectional view of the photodetector shown in FIG. 2(A) and FIG. 2(B), A first photodiode 102A and a second photodiode 102B for infrared light and visible light The arrows in Figure 3(A) show the state of incidence of the first In addition to the photodiode 102A and the second photodiode 102B, the backlight 30 3, a liquid crystal layer 301, an opposing substrate 302, and an object to be detected 303. The substrate 02 may be made of the same material as the light-transmitting substrate 200. Electrodes for displaying the image, color filters, polarizing plates, and alignment films that are provided as necessary. The configuration of the backlight 300 in FIG. As the light source, a light source capable of emitting infrared light and visible light separately from the light-transmitting substrate 200 side is used. The backlight 300 is configured as a light-emitting diode that emits infrared light. A light emitting diode that emits visible light and a light emitting diode that emits visible light may be arranged side by side.

[0070] In one embodiment of the present invention, as shown by the dashed arrow 304 in FIG. 3, After passing through the liquid crystal layer 301, the infrared light from the backlight passes through the counter substrate 302. The light that has passed through the counter substrate 302 is reflected by a finger, which is an object to be detected 303, and is then reflected back onto the counter substrate 302. The light incident on the counter substrate 302 is incident on the first photodiode 102A. The light passes through the photodiode 102B and enters the second photodiode 102B. The display device having the device detects infrared light by the second photodiode 102B, Equipped with an optical touch panel function that detects objects such as fingers without being affected by external light. The configuration can be such that:

[0071] In one embodiment of the present invention, as shown by the dashed line arrow 305 in FIG. Visible light from the backlight passes through the liquid crystal layer 301 and then through the opposing substrate 302. The light that has passed through the opposing substrate 302 is then perceived by the viewer. The light passes through the substrate 302 and the liquid crystal layer 301 and enters the first photodiode 102A. In addition, the display device including the photodetector according to the present embodiment includes a first photodiode 1 The 02A detects visible light, allowing the touch panel to function without being affected by external light. In addition, the present invention may be configured to have a scanner function for detecting an object to be detected, such as a color image. do.

[0072] Also, FIG. 3(B) shows a backlight configuration different from that of FIG. 3(A). The backlight shown in (B) has a light source for emitting visible light and also emits infrared light. It is equipped with a front light for illumination.

[0073] The front light shown in FIG. 3B includes a light source 306, a light guide plate 307, a fixing material 308, and The front light shown in FIG. 3B includes a first photodiode 102A. and overlaps with the second photodiode 102B.

[0074] The light source 306 may be a light emitting diode that emits infrared light.

[0075] The fixing material 308 has a function of fixing the light source 306 and the light guide plate 307. It is preferable to use a material having a light-shielding property as the fixing material 308. By using such a material, the light emitted from the light source 306 is prevented from leaking to the outside. It should be noted that the fixing material 308 does not necessarily have to be provided.

[0076] In the front light shown in FIG. 3B, light from a light source 306 is incident on a light guide plate 307. For example, when the object 303 to be detected is not in contact with the light guide plate 307, the light from the light source 306 is guided The light is totally reflected inside the plate 307. When the object 303 to be detected, such as a finger, comes into contact with the light guide plate 307, The light from the light source 306 is scattered at the contact portion between the object 303 and the light guide plate 307. The light passes through the first photodiode 102A and enters the second photodiode 102B.

[0077] By using the configurations shown in FIG. 3(A) and FIG. 3(B), the first photodiode, which is a visible light sensor, A first photodiode 102A and a second photodiode 102B which is an infrared light sensor are arranged in parallel. In a photodetector configured with a single sensor, the area occupied by each sensor is shared, reducing the area occupied by each sensor. As a result, the area required for arranging each sensor can be reduced. Therefore, it is possible to provide a photodetector device that can reduce the pixel size. The area of ​​the sensor can be increased, so the sensitivity of each sensor to visible light and infrared light can be increased. It can be improved.

[0078] The semiconductor layer of the first photodiode 102A, which is a visible light sensor, is made of amorphous silicon. The lens has the characteristic of absorbing visible light incident from the outside and transmitting infrared light incident from the outside. As a result, by using the configuration shown in FIG. 3, the second photodiode, which is an infrared light sensor, Therefore, the incidence of visible light on the semiconductor layer 102B can be reduced. In the case of the second photodiode 102B configured to detect infrared light as a photodiode, Therefore, it is necessary to provide an optical filter on the second photodiode 102B to reduce the noise of the second photodiode 102B. Since there is no need for a solder joint, the manufacturing cost can be reduced.

[0079] Next, an example of a configuration having a plurality of photodetectors 101 shown in FIG. 1A in a matrix form will be described. Shown in Figure 4(A).

[0080] In FIG. 4A, a plurality of photodetecting devices 101 are arranged in m (m is a natural number of 2 or more) rows and n (n is a natural number of 2 or more). The photodetector devices 10 in each row shown in FIG. 1 is connected to any one of a plurality of reset control lines PR (written as lines PR1 to PRm). , any one of a plurality of transfer control lines TX (represented as wiring TX1 to wiring TXm) and a plurality of One of the selection control lines SE (referred to as lines SE1 to SEm) and a plurality of power supply lines V R (written as wiring VR1 to wiring VRm) and an example of Each row of the photodetector 101 shown in FIG. (Will be referred to as wiring VIOUT1 to wiring VIOUTn) and multiple second outputs Any one of the signal lines IROUT (written as lines IROUT1 to IROUTn) The figure shows an example of a 32-bit LSI connected to a

[0081] In FIG. 4A, the photodetector devices in each row share a transfer control line TX. A reset control line PR is shared between the photodetectors in each row, and a selection control line SE is shared between the photodetectors in each row. The photodetectors in each row share a power supply line VR, and the photodetectors in each column share a first output The input signal line VIOUT is shared, and the second output signal line IROUT is provided to the photodetector of each column. The configuration is not limited to the above, and two or more transfer control lines TX may be provided in each row. Alternatively, each row may be connected to a different photodetector 101. R may be provided to connect to different photodetectors 101. Alternatively, two or more selection lines may be provided in each row. Alternatively, a selection control line SE may be provided to connect the photodetectors 101 different from each other. Alternatively, two or more power supply lines VR may be provided to connect the different photodetectors 101. Two or more first output signal lines VIOUT and / or second output signal lines IROUT are provided in a row. Alternatively, two photodetectors 101 may be provided and connected to different photodetectors 101 .

[0082] In addition, in FIG. 4A, the wiring VR is shared by the photodetectors in each row. The wiring VR may be shared by the photodetectors in each column.

[0083] Next, the operation of the photodetector 101 will be described. Each wiring (transfer control line TX, reset control line PR, selection control line SE, first output signal line VI OUT (second output signal line IROUT), and a second transistor 105A (second transistor The change in the potential (indicated as FD in FIG. 4B) corresponding to the gate potential of the transistor 105B 4B is an example of a timing chart showing the first photodiode. The operation of the second photodiode 102A and the first amplifier circuit 103A, and the operation of the second photodiode 1 Since the operation of the first amplifier circuit 102B and the second amplifier circuit 103B is the same as that of the first amplifier circuit 103B, The operation of the photodiode 102A and the first amplifier circuit 103A will be described. Let us assume that.

[0084] In addition, in the timing chart shown in FIG. 4B, Therefore, the transfer control line TX, the selection control line SE, and the reset control line PR are set to high or low. It is assumed that a high level potential is applied to the transfer control line TX. A high level potential HTX and a low level potential LTX are applied to the selection control line SE. A high-level potential HSE and a low-level potential LSE are applied. The wire PR is supplied with a high-level potential HPR and a low-level potential LPR. do.

[0085] The first transistor 104A, the second transistor 105A, and the third transistor In the following description, it is assumed that all the transistors 106A are n-channel transistors. The conductivity type of the transistor may be a p-channel type transistor, in which case the signal supplied to each terminal The polarity can be set to be inverted.

[0086] First, at time T1, the potential of the transfer control line TX is changed from the potential LTX to the potential HTX. When the potential of the transfer control line TX becomes the potential HTX, the first transistor 104A is turned on. At time T1, the selection control line SE is applied with a potential LSE, and the reset state is A potential LPR is applied to the bit control line PR.

[0087] At time T2, the potential of the reset control line PR is changed from the potential LPR to the potential HPR. At time T2, the potential of the transfer control line TX remains at the potential HTX. The potential of the line SE remains at the potential LSE. Thus, a resistor is applied to the gate (FD) of the second transistor 105A. Since the potential HPR of the set control line PR is applied, the gate of the second transistor 105A The charge held in (FD) is discharged.

[0088] At time T3, the potential of the reset control line PR is changed from the potential HPR to the potential LPR. Until just before time T3, the potential of the gate (FD) of the second transistor 105A is the potential H PR, when the potential of the reset control line PR becomes the potential LPR, A reverse bias voltage is applied to the first diode 102A. With a reverse bias voltage applied to the photodiode 102A, the first photodiode When visible light is incident on the first photodiode 102A, a reset control is generated in the first photodiode 102A. A current (photocurrent) flows in the direction of the line PR. The value of the photocurrent changes according to the intensity of the incident light. That is, the higher the intensity of the light incident on the first photodiode 102A, the higher the photodiode The current value of the current becomes high, and the gate (FD) of the second transistor 105A and the first photodiode The amount of charge moving between the first photodiode 102A also increases. The lower the intensity of the light incident on the second transistor 102A, the lower the current value of the photocurrent. The amount of charge moving between the gate (FD) of 105A and the first photodiode 102A is also Therefore, the potential of the gate (FD) of the second transistor 105A becomes smaller as the light intensity The higher the intensity, the greater the change, and the lower the light intensity, the smaller the change.

[0089] At time T4, when the potential of the transfer control line TX is changed from the potential HTX to the potential LTX, The first transistor 104A is turned off. The transfer of charges between the gate (FD) and the first photodiode 102A stops, so The potential of the gate (FD) of the second transistor 105A is determined.

[0090] At time T5, the potential of the selection control line SE is changed from the potential LSE to the potential HSE. The third transistor 106A is turned on. Then, the potential of the wiring Charge transfer occurs between VR and the first output signal line VIOUT.

[0091] Before time T5, the potential of the first output signal line VIOUT is set to a predetermined potential (program In FIG. 4B, the first output signal line VIOU The potential of T is precharged to a low level potential before time T5, and the potential of T is The case where the potential of the first output signal line VIOUT rises in response to the light intensity during The potential of the first output signal line VIOUT is set to a high level potential before time T5. , and the first output signal line VI The potential of OUT may decrease.

[0092] The precharge operation is performed by, for example, connecting the first output signal line VIOUT and a line to which a predetermined potential is applied. The line is electrically connected to the transistor through a switching element such as a transistor. After the precharge operation is completed, The transistor is in an off state.

[0093] At time T6, the potential of the selection control line SE is changed from the potential HSE to the potential LSE. The transfer of charges from the wiring VR to the first output signal line VIOUT stops, and the first output signal line V The potential of the first output signal line VIOUT is determined. The potential of the output signal corresponds to the potential of the output signal of the sensor 1. The potential of the output signal includes information about the object to be detected. is.

[0094] The above series of operations of the photodetector 101 can be classified into a reset operation, a storage operation, and a selection operation. That is, the operation from time T2 to time T3 is the reset operation, and the operation from time T3 to The operation up to time T4 corresponds to the accumulation operation, and the operation from time T5 to time T6 corresponds to the selection operation. In addition, the period from the end of the storage operation to the start of the selection operation, that is, time T4 The period from time T1 to time T5 is when a charge is generated at the gate (FD) of the second transistor 105A. This corresponds to the charge retention period during which the charge is retained. In each photodetector, a reset operation, a storage operation, and a selection operation are sequentially performed. A ring shutter system can be used. In each photodetector, the reset operation and the accumulation operation are performed simultaneously, and the selection operation is performed in sequence. The so-called global shutter method can be used.

[0095] When the potential of the transfer control line TX is changed at time T1 or time T4, The parasitic capacitance between the control line TX and the gate (FD) of the second transistor 105A causes the The potential of the gate (FD) of the transistor 105A in the second transistor changes. This change in potential is large. In this case, the output signal cannot be output accurately. In order to suppress the change in the potential of the gate (FD) of the second transistor 105A during The capacitance between the gate and source or between the gate and drain of the transistor 104A is reduced. It is also effective to increase the gate capacitance of the second transistor 105A. Furthermore, it is effective to electrically connect a capacitance element to the gate (FD) of the second transistor 105A. In Figure 4(B), these measures are taken to prevent the When the potential of the transmission control line TX is changed, the gate (FD) of the second transistor 105A The change in potential is assumed to be negligible.

[0096] For each row of photodetector 101, a transfer control line TX, a reset control line PR and a selection control The first amplifier circuit 103A and the second amplifier circuit 103B are connected to each other. It is effective to configure the photodetector 101 so that the operation in the photodetector 101 is performed independently of the operation in the photodetector 103B. Then, one electrode of the first photodiode 102A is connected to a first reset control line, One electrode of the second photodiode 102B is connected to the second reset control line, and the first The gate of the transistor 104A is connected to the first transfer control line, and the first transistor 104 B is connected to the second transfer control line, and the gate of the third transistor 106A is connected to the first the gate of the third transistor 106B is connected to the second selection control line; The first transfer control line and the second transfer control line are controlled independently, and the first reset control line and The first selection control line and the second selection control line are independently controlled. It is effective to have a configuration in which the control is performed independently. In the first period, the first amplifier circuit 103A The operation in the first amplifier circuit 103B is performed independently of the operation in the second amplifier circuit 103B, and in the second period, The operation of the first amplifier circuit 103A and the operation of the second amplifier circuit 103B are performed in parallel. The configuration may be such that

[0097] As an example of the above configuration, in the photodetector 101, the first photodiode 102A With such a configuration, the light detection device 101 can be configured to perform detection only by the light. It is possible to reduce power consumption. Specifically, in the first amplifier circuit 103A, When performing the storage operation and the selection operation, the second amplifier circuit 103B performs a reset operation, a storage operation, and a selection operation. In the first period, at least one of the following operations is not performed: In the second period, detection is performed only by the first photodiode 102A, and the first amplification circuit The operation of the first amplifier circuit 103A and the operation of the second amplifier circuit 103B are performed in parallel. This is also fine.

[0098] As another example of the above configuration, in the photodetector 101, the second amplifier circuit 103B When performing a reset operation, a storage operation, and a selection operation in the first amplifier circuit 103A, It is possible to configure the photodetector 101 so that it only performs the accumulation operation. It is possible to reduce power consumption. Furthermore, the first photodiode 102A receives light in a specific wavelength range. Since it functions as a filter that absorbs the light detected by the second photodiode 102B, It is possible to improve the accuracy. In the first period, the second amplifier circuit 103B When performing a reset operation, a storage operation, and a selection operation in the first amplifier circuit 103A, In the second period, the first amplifier circuit 103A and the second amplifier circuit 103B perform only the accumulation operation. The operation of the amplifier circuit 103B may be performed in parallel with the operation of the amplifier circuit 103B.

[0099] As described above, in the configuration of this embodiment, the first photodiode, which is a visible light sensor, A photodetection device comprising a first photodiode and a second photodiode serving as an infrared light sensor, arranged in parallel. In this case, the area required for each sensor can be shared, making it possible to reduce the area required for each sensor. As a result, the area required for arranging each sensor can be reduced, which leads to a reduction in pixel size. Therefore, it is possible to provide a light detection device in which the area of ​​each sensor can be relatively large. This can improve the sensitivity of each sensor to visible light and infrared light. do.

[0100] In the configuration of this embodiment, the semiconductor layer of the first photodiode, which is a visible light sensor, Amorphous silicon absorbs visible light incident from the outside and blocks infrared light incident from the outside. As a result, visible light is transmitted to the second photodiode, which is an infrared light sensor. It is possible to reduce the incidence of light. Therefore, it is possible to detect infrared light by using crystalline silicon as a semiconductor layer. In the case of the second photodiode having such a configuration, the noise generated when infrared light is detected due to the incidence of visible light is This eliminates the need for a separate optical filter on the second photodiode to reduce noise, making manufacturing easier. This allows for a reduction in manufacturing costs.

[0101] (Embodiment 2) In this embodiment, in addition to the plurality of photodetectors arranged in a matrix, An example of the configuration of a display device having a plurality of display elements arranged in a matrix will be described. Such a display device is called an optical touch panel, and the display screen also serves as an information input area. The configuration of the photodetector and the connection between the photodetectors are the same as those shown in the first embodiment. The operation of the photodetector can be the same as that shown in the first embodiment. can be carried out in the same manner.

[0102] FIG. 5 shows a circuit diagram of a part of the configuration of a display device. In FIG. 5, a pixel 520 is a four-display element. The pixel 520 is a basic component, and the pixel 520 are arranged in a matrix of m rows and n columns to form a display screen that also serves as an information input area. In FIG. 5, the photodetector 101 having the configuration shown in FIG. 1(A) is used for the pixel 520. The number of display elements 521 and photodetectors 101 in each pixel is The arrangement density of the plurality of light detection devices and the plurality of display elements is not limited to the form shown in FIG. They may be the same or different. In other words, one light detection device for each display element. Alternatively, one photodetector may be arranged for two or more display elements. Alternatively, one display element may be arranged for two or more light detection devices.

[0103] In the configuration shown in FIG. 5, a display element 521 includes a liquid crystal element 522. The element 521 includes a liquid crystal element 522 and a circuit such as a transistor for controlling the operation of the liquid crystal element 522. Specifically, in FIG. 5, a display element 521 includes a liquid crystal element 522 and a switch. 5 shows an example in which a transistor 523 functioning as a switching element and a capacitor 524 are included. The liquid crystal element 522 includes a pixel electrode, a counter electrode, and a liquid crystal layer formed between the pixel electrode and the counter electrode. The liquid crystal layer has a voltage applied thereto.

[0104] The gate electrode of the transistor 523 is connected to the scanning line GL (GL1, GL2). The first terminal of the transistor 523 is connected to the signal line SL (SL1, SL2). The two terminals of the capacitor 524 are connected to the pixel electrode of the liquid crystal element 522. One of the electrodes is connected to the pixel electrode of the liquid crystal element 522, and the other is a wiring to which a fixed potential is applied. A potential corresponding to the image to be displayed is input to the signal line SL. When the transistor 523 is turned on by the signal of the scanning line GL, the potential of the signal line SL becomes A current is applied to one of a pair of electrodes of the capacitor 524 and a pixel electrode of the liquid crystal element 522. The capacitance element 524 holds a charge corresponding to the voltage applied to the liquid crystal layer. By applying a voltage to the liquid crystal layer, the polarization direction of the liquid crystal layer changes, and this is used to produce a gradation of light passing through the liquid crystal layer. The light that passes through the liquid crystal layer is reflected by the backlight and is called visible light. Use light.

[0105] In the configuration shown in FIG. 5, the operation of the display elements arranged in a matrix is ​​performed according to a known method. The display device may be the same as that of the display device described above.

[0106] The transistor 523 is manufactured in the same process as the transistor included in the photodetector 101. As a result, the manufacturing process of the display device can be simplified.

[0107] This embodiment mode can be freely combined with other embodiment modes.

[0108] (Embodiment 3) The photodetection device according to one aspect of the present invention can improve the sensitivity of the sensor and reduce the manufacturing cost. It has the following characteristics:

[0109] The photodetector according to one aspect of the present invention can be used in a display device, a notebook personal computer, a recording device, and the like. Image playback device equipped with a medium (typically DVD: Digital Versatile (Devices with a display that can play back recording media such as discs and display the images) In addition, a photodetector according to one embodiment of the present invention can be used. As child devices, mobile phones, portable game consoles, personal digital assistants, electronic books, video cameras, Digital still camera, goggle-type display (head-mounted display), navigation systems, audio playback devices (car audio, digital audio players, etc.) , copiers, facsimiles, printers, printer-combination machines, automated teller machines (A TM), vending machines, etc. Specific examples of these electronic devices are shown in Figure 6.

[0110] FIG. 6A shows a display device, which includes a housing 5001, a display portion 5002, a support stand 5003, etc. The photodetector according to one embodiment of the present invention can be used for the display portion 5002. By using a photodetector according to one embodiment of the present invention in 5002, the sensitivity of the sensor can be improved. It is possible to provide a display device that can reduce manufacturing costs. This includes all information display devices such as for global computers, TV broadcast reception, and advertisement displays. Can be enjoyed.

[0111] FIG. 6B shows a portable information terminal, which includes a housing 5101, a display unit 5102, operation keys 5103, etc. The photodetector according to one embodiment of the present invention can be used in the display portion 5102. The photodetector according to one embodiment of the present invention is used for the display portion 5102, thereby improving the sensitivity of the sensor. It is possible to provide a portable information terminal that can reduce manufacturing costs.

[0112] FIG. 6C shows an automated teller machine, which includes a housing 5201, a display unit 5202, and a coin insertion unit. 5203, a bill insertion slot 5204, a card insertion slot 5205, a bankbook insertion slot 5206, etc. The photodetector according to one embodiment of the present invention can be used for the display portion 5202. By using a photodetection device according to one embodiment of the present invention in the sensor 5202, the sensitivity of the sensor can be improved. It is possible to provide an automated teller machine capable of reducing manufacturing costs.

[0113] FIG. 6D shows a portable game machine, which includes a housing 5301, a housing 5302, a display portion 5303, and a display portion 5304. A display unit 5304, a microphone 5305, a speaker 5306, an operation key 5307, a style The photodetector according to one embodiment of the present invention includes a display portion 5303 or a display The display portion 5303 or the display portion 5304 may be used as one of the display devices of the present invention. By using the light detection device according to the embodiment, the sensitivity of the sensor can be improved and the manufacturing cost can be reduced. It is possible to provide a portable game machine that can play the game. The display unit 5303 and the display unit 5304 are the same as those of the portable game machine. The number of display parts is not limited to this.

[0114] This embodiment mode can be implemented in appropriate combination with any of the above embodiment modes.

[0115] (Embodiment 4) In the configuration disclosed in the first embodiment, the first transistor 104A and the first transistor The transistor 104B is preferably a transistor with an extremely small off-state current. With such a configuration, the first photodiode 102A and the second photodiode 1 The retention characteristics of the charge accumulated in response to the photocurrent in the 02B and 02C can be improved. Therefore, the detection accuracy of the light detection device 101 can be improved. When the global shutter method is used as the driving method for the device, the charge is Since the retention periods are different, the above-mentioned structure is preferable. To achieve this, the semiconductor layers of the first transistor 104A and the second transistor 104B are For example, the semiconductor layer may be made of an oxide semiconductor that is a wide-gap semiconductor. It is preferred.

[0116] The oxide semiconductor layer is formed of a quaternary metal oxide, In-Sn- Ga-Zn oxide, ternary metal oxide In-Ga-Zn oxide, In-Sn -Zn oxide, In-Al-Zn oxide, Sn-Ga-Zn oxide, Al-Ga- Zn-based oxide, Sn-Al-Zn-based oxide, In-Hf-Zn-based oxide, In-La-Z n-type oxide, In-Ce-Zn-type oxide, In-Pr-Zn-type oxide, In-Nd-Zn In-Sm-Zn oxide, In-Eu-Zn oxide, In-Gd-Zn oxide Oxide, In-Tb-Zn oxide, In-Dy-Zn oxide, In-Ho-Zn oxide oxides, In-Er-Zn oxides, In-Tm-Zn oxides, In-Yb-Zn oxides In-Lu-Zn ​​oxides, binary metal oxides such as In-Zn oxides, Sn- Zn-based oxide, Al-Zn-based oxide, Zn-Mg-based oxide, Sn-Mg-based oxide, In- Mg-based oxide, In-Ga-based oxide, indium oxide, tin oxide, zinc oxide, etc. In addition, the above materials may contain SiO2. -Ga-Zn oxide is a compound containing indium (In), gallium (Ga), and zinc (Zn). The composition ratio is not particularly important. The oxide semiconductor layer may be single-crystal or non-single-crystal. In the case of non-single crystal, it may be amorphous or polycrystalline. Also, it may have crystalline in the amorphous state. The structure may include a portion having the above structure, or may be non-amorphous.

[0117] In the configuration disclosed in the first embodiment, the first transistor 104A and the second transistor When the semiconductor layer of the photodiode 104B is made of an oxide semiconductor, for example, a second photodiode is formed on the substrate. The diode 102B, the second transistor 105A, the second transistor 105B, and the third The first transistor 106A and the third transistor 106B are formed, and the second photodiode The second transistor 105A, the second transistor 105B, and the third transistor A first insulating film is formed on the first transistor 106A and the third transistor 106B. A first transistor 104A and a second transistor 104B are formed on the insulating film. A second insulating film is formed on the first transistor 104A and the first transistor 104B. The second photodiode 102B may be formed on the second insulating film. do.

[0118] This embodiment mode can be implemented in appropriate combination with any of the above embodiment modes. [Explanation of symbols]

[0119] 101 Photodetector 102A First Photodiode 102B Second Photodiode 103A First Amplifier Circuit 103B Second amplifier circuit 104A First Transistor 104B first transistor 105A second transistor 105B Second transistor 106A Third Transistor 106B Third transistor 107 Transfer Control Line 108 Power line 109 Selection control line 110A First output signal line 110B Second output signal line 111 Reset control line 200 Transparent substrate 201 Light blocking layer 202 Base film 203 p-type semiconductor region 204 i-type semiconductor region 205 n-type semiconductor region 206 i-type semiconductor region 207 n-type semiconductor region 208 i-type semiconductor region 209 n-type semiconductor region 210 Insulating layer 211 Gate electrode 212 Gate electrode 213 Insulating Layer 214 Conductive layer 215 Conductive Layer 216 Conductive Layer 217 Conductive Layer 218 p-type semiconductor region 219 i-type semiconductor region 220 n-type semiconductor region 221 Insulating layer 222 Conductive Layer 223 n-type semiconductor region 224 Conductive layer 261 Conductive Layer 300 Backlight 301 Liquid crystal layer 302 Opposing substrate 303 Detected object 304 Dashed Arrow 305 dashed arrow 306 Light source 307 Light guide plate 308 Fixed material 520 pixels 521 Display element 522 Liquid crystal element 523 Transistor 524 Capacitive element 5001 Case 5002 Display section 5003 Support stand 5101 Case 5102 Display section 5103 Operation key 5201 Case 5202 Display section 5203 Coin slot 5204 Bill slot 5205 Card slot 5206 Passbook slot 5301 Case 5302 Case 5303 Display section 5304 Display section 5305 Microphone 5306 Speaker 5307 Operation key 5308 Stylus

Claims

[Claim 1] a first photodiode for detecting visible light, a second photodiode for detecting infrared light, a first amplifier circuit for amplifying and outputting a charge accumulated in response to a photocurrent in the first photodiode, and a second amplifier circuit for amplifying and outputting a charge accumulated in response to a photocurrent in the second photodiode, the semiconductor layer of the first photodiode is made of amorphous silicon; the semiconductor layer of the second photodiode is made of crystalline silicon; the first photodiode and the second photodiode are provided to overlap each other such that the first photodiode is located on a side on which incident light including the visible light and the infrared light is incident, the first photodiode absorbs the visible light and transmits the infrared light of the incident light; a second photodiode that absorbs the infrared light that is transmitted through the first photodiode from the incident light;

Images