Light detection device

Abstract

A device comprising a substrate and a plurality of pixel portions, the plurality of pixel portions including: a first light detecting element located in the pixel portion within an active area; and a second light detecting element located in the pixel portion within an inactive area. The first light detecting element comprises a first lower electrode layer, a first lower impurity semiconductor layer, a first intrinsic semiconductor layer, a first upper impurity semiconductor layer, and a first upper electrode layer; and the second light detecting element comprises a second lower electrode layer, a second lower impurity semiconductor layer, a second intrinsic semiconductor layer, a second upper impurity semiconductor layer, and a second upper electrode layer, wherein the second lower electrode layer is covered by the second lower impurity semiconductor layer and the second intrinsic semiconductor layer.

Description

Technical Field

[0001] The present disclosure relates to a light detection device used to obtain an image of a subject, etc. by photoelectrically converting light. Background Art

[0002] An example of the prior art is described in Patent Document 1.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-92077 Summary of the Invention

[0006] The light detection device disclosed in the present invention includes: a substrate; a plurality of pixel portions arranged in a row direction and a column direction on the substrate and configured in a matrix shape; a first light detection element, which is provided in a pixel portion located in an effective area used in light detection on the substrate among the plurality of pixel portions; and a second light detection element, which is provided in a pixel portion located in an ineffective area surrounding the effective area and not used in light detection on the substrate among the plurality of pixel portions, the first light detection element having: a first lower electrode layer, which is configured on the substrate; a first lower impurity semiconductor layer, which is configured on the inner side of the first lower electrode layer when viewed from above, and includes a first impurity semiconductor; a first intrinsic semiconductor layer, which is configured The second light detecting element comprises: a first lower impurity semiconductor layer disposed on the first intrinsic semiconductor layer; a first upper impurity semiconductor layer disposed on the first intrinsic semiconductor layer and including a second impurity semiconductor; and a first upper electrode layer disposed on the first upper impurity semiconductor layer. The second light detecting element comprises: a second lower electrode layer disposed on the substrate; a second lower impurity semiconductor layer disposed on the second lower electrode layer to cover the second lower electrode layer and including the first impurity semiconductor; a second intrinsic semiconductor layer disposed on the second lower impurity semiconductor layer; a second upper impurity semiconductor layer disposed on the second intrinsic semiconductor layer and including the second impurity semiconductor; and a second upper electrode layer disposed on the second upper impurity semiconductor layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The objects, features and advantages of the present disclosure will become clear from the following detailed description and accompanying drawings.

[0008] Figure 1 This is a cross-sectional view of a pixel portion included in a photodetection device according to one embodiment of the present disclosure.

[0009] Figure 2 This is a block diagram showing the structure of a light detection device.

[0010] Figure 3 It is a top view of the pixel portion.

[0011] Figure 4A This is a cross-sectional view showing a simplified structure of a first light detection element arranged in the effective area.

[0012] Figure 4B This is a cross-sectional view showing a simplified structure of a second light detecting element arranged in the ineffective area.

[0013] Figure 5A These are diagrams for explaining the steps of forming the first lower impurity semiconductor layer, the first intrinsic semiconductor layer, and the first upper impurity semiconductor layer in the first photodetection element.

[0014] Figure 5B These are diagrams for explaining the steps of forming the second lower impurity semiconductor layer, the second intrinsic semiconductor layer, and the second upper impurity semiconductor layer in the second photodetection element having the structure that is the basis of the present disclosure.

[0015] Figure 6 It is a cross-sectional view of a second light detection element included in a light detection device according to another embodiment of the present disclosure.

[0016] Figure 7 It is a cross-sectional view showing the structure of a pixel portion having an effective region of a first light detection element. DETAILED DESCRIPTION

[0017] Hereinafter, embodiments of the light detection device disclosed herein will be described with reference to the accompanying drawings.

[0018] The photodetection device, which forms the basis of the present disclosure, includes multiple pixel units. Each pixel unit includes a thin-film transistor (TFT) formed on a substrate and functioning as a switching element; a photoelectric conversion unit (PCM) stacked on the TFT with an insulating layer interposed therebetween, functioning as a photodetection element; and contact holes for electrically connecting the PCM unit to the electrodes of the TFT. The PCM unit comprises a first electrode layer, a first impurity semiconductor layer, an intrinsic semiconductor layer, a second impurity semiconductor layer, and a second electrode layer stacked from one side of the TFT. The multiple pixel units are arranged in a matrix in the row and column directions.

[0019] In the photodetection device of the structure that forms the basis of the photodetection device disclosed herein, a first electrode layer, a first impurity semiconductor layer, an intrinsic semiconductor layer, a second impurity semiconductor layer, and a second electrode layer are stacked on an insulating layer to form a photoelectric conversion portion. After forming the materials for each layer of the first electrode layer, the first impurity semiconductor layer, the intrinsic semiconductor layer, the second impurity semiconductor layer, and the second electrode layer by sputtering or plasma CVD, a photolithography process (exposure process) is performed. During patterning or dry etching to remove residual photoresist, the decomposition reaction rate of the mask material in the plasma atmosphere of the etching gas tends to be higher in the center of the chamber and lower in the peripheral portion close to the chamber wall.

[0020] In the dry etching process, in the substrate placed in the chamber, an effective area where a pixel portion used in light detection is formed is located near the center of the chamber, and an ineffective area where a dummy pixel portion not used in light detection is formed is located near the periphery of the chamber. For this reason, the etching rate of the pixel portion located in the ineffective area is reduced during the dry etching process of the intrinsic semiconductor layer in the manufacturing process. In other words, the etching speed is reduced. For this reason, after the intrinsic semiconductor layer and the first impurity semiconductor layer of the pixel portion arranged in the effective area with a high etching rate are etched, the etching is concentrated on the first electrode layer in the effective area. As a result, the etching rate of the ineffective area is further reduced, and etching residues are easily generated in the first impurity semiconductor layer and the intrinsic semiconductor layer of the pixel portion located in the ineffective area, which is likely to reduce the manufacturing yield.

[0021] Figure 1 is a cross-sectional view of a pixel portion included in a light detection device according to one embodiment of the present disclosure. Figure 2 is a block diagram showing the structure of a light detection device, Figure 3 is a top view of the pixel portion. Figure 1 Indicates from Figure 3The photodetection device of this embodiment comprises: a substrate 1, such as a glass substrate; and a plurality of pixel units 40 arranged in a matrix in row and column directions on the substrate 1. The plurality of pixel units 40 include: a photodetection element 30, which performs photoelectric conversion on incident light and outputs a light-receiving signal; and a thin-film transistor (TFT) 31, which extracts the charge photoelectrically converted by the photodetection element 30 as an electrical signal and serves as a switching element. The photodetection element 30 functions as a photoelectric conversion unit that converts light into charge, forming a PIN-type photodiode. A PIN-type photodiode has a structure in which an intrinsic semiconductor layer (I-type semiconductor layer) is sandwiched between PN junctions. The difference from a PN-type photodiode is that the presence of the intrinsic semiconductor layer increases the depletion layer when a reverse voltage is applied. This enables high-speed response characteristics. Furthermore, the dark current when a reverse voltage is applied is better than that of a PN-type photodiode.

[0022] The material of the substrate 1 can be a glass material, an acrylic resin, a polycarbonate, a resin material such as polyethylene terephthalate, a ceramic material such as alumina ceramic, etc. In addition, the substrate 1 can be a composite substrate obtained by laminating multiple substrates containing any one of a glass material, a resin material, and a ceramic material. In addition, the substrate 1 can also be a flexible substrate containing a flexible material such as the above-mentioned resin material. In this case, the substrate 1 is lightweight and can be arranged along the curved surface of the human body. Furthermore, since the impact resistance of the substrate 1 is improved, even if it falls during transportation, collides with other components and devices, etc., it can effectively suppress damage to the substrate 1.

[0023] The light detecting element 30 is formed on the insulating layer 8 stacked on the TFT 31 formed on the substrate 1. The light detecting element 30 and the drain electrode 4b of the TFT 31 are electrically connected via the lower contact hole 20. The light detecting element 30 has a structure comprising a lower electrode layer 9, a lower impurity semiconductor layer 10, an intrinsic semiconductor layer 11, an upper impurity semiconductor layer 12, and an upper electrode layer 13 stacked from the substrate 1 side. The lower contact hole 20 may also have a structure comprising: a portion of the lower electrode layer 9 formed on the inner peripheral surface of a recessed portion formed at a predetermined location where the insulating layer 8 is removed by etching or the like; and an insulating filler material 20a filling the space surrounded by the lower electrode layer 9.

[0024] In addition, impurity semiconductors are pure intrinsic semiconductors with trace amounts of added (doped) 10 16 cm -3 ~10 17 cm -3Semiconductors containing impurities (dopants) are classified by the doping element into p-type semiconductors, where holes are the carriers, and n-type semiconductors, where electrons are the carriers. Whether a semiconductor is p-type or n-type depends on the valence of the impurity element and the valence of the semiconductor being replaced by the impurity. For example, when silicon (Si) with a valence of 4 is doped with phosphorus (P) or arsenic (As) with a valence of 5, it becomes an n-type semiconductor. Doping with boron (B) or aluminum (Al) with a valence of 3, it becomes a p-type semiconductor.

[0025] constitute Figure 1 The insulating filling material 20a of the lower contact hole 20 shown can be made of an organic material. As the organic material, acrylic resin, silicone resin, polyimide, polyamide, polyamideimide, benzocyclobutene, polysiloxane, polysilazane, etc. can be used. Polysiloxane forms a skeleton structure by coupling silicon (Si) and oxygen (O). As its substituent, at least a hydrogen-containing organic group, such as an alkyl group, an aromatic hydrocarbon group, etc. is used. In addition, as a substituent, a fluorine group, an organic group containing at least hydrogen, and a fluorine group can also be used. Polysilazane is a material formed by forming a polymer material having a coupling of silicon (Si) and nitrogen (N) as a starting material.

[0026] The insulating filler 20a can be made of a photosensitive organic resin or a thermosetting resin that cures with ultraviolet light or other light. When using a photosensitive organic resin, the lower contact hole 20 can be filled with an uncured paste of the organic resin, which is then irradiated with ultraviolet light or other light. The insulating filler can also be cured by heating.

[0027] The pixel portion 40 is as follows Figure 3 As shown in FIG. 1 , the shape is rectangular when viewed from above, and an upper contact hole 22 for applying a bias voltage to the light detection element 30 is formed at one corner thereof. In addition, a bias line 16 for supplying a bias voltage to the light detection element 30 is formed along the source signal line 32 on one side of the light receiving surface of the pixel portion 40. In addition, the TFT 31 is formed at the other corner diagonally opposite to the one corner of the pixel portion 40 when viewed from above. Figure 1As shown, the pixel portion 40 includes a first semiconductor layer 6a serving as a channel portion, an etch stopper layer 5 made of silicon nitride (SiNx), a second semiconductor layer 6b, a source electrode 4a, and a drain electrode 4b. The second semiconductor layer 6b electrically connects the first semiconductor layer 6a to the source electrode 4a and the drain electrode 4b. Furthermore, the lower contact hole 20 is formed near the center of the pixel portion 40 to guide the charge photoelectrically converted by the light detection element 30 to the drain electrode 4b of the TFT 31. The source signal line 32 outputs the charge photoelectrically converted by the light detection element 30 as an electrical signal corresponding to the amount of charge.

[0028] The TFT 31 may be a channel stop type having an etch stop layer 5 or a back channel cut type. The semiconductor constituting the TFT 31 may be an oxide semiconductor such as low-temperature polysilicon (LTPS) or indium gallium zinc oxide (IGZO).

[0029] Substrate 1 includes a glass substrate or the like. Gate lines 2 for controlling the on / off switching of TFTs 31 are formed on one side of substrate 1 (the side where the pixel portion is arranged). A gate insulating layer 3 is formed to cover the one side of substrate 1 and gate lines 2. A first semiconductor layer 6a, comprising amorphous silicon (a-Si), or the like, serving as a channel portion, is formed on gate insulating layer 3 in a portion covering gate lines 2. An etch stop layer 5 is formed on first semiconductor layer 6a in a portion overlapping gate lines 2. A second semiconductor layer 6b, comprising n+-type a-Si, or the like, is formed to cover etch stop layer 5 and first semiconductor layer 6a. A source electrode 4a and a drain electrode 4b, comprising a metal such as tantalum (Ta), neodymium (Nd), tungsten (W), titanium (Ti), molybdenum (Mo), aluminum (Al), chromium (Cr), silver (Ag), or an alloy thereof, are formed on second semiconductor layer 6b to form TFTs 31.

[0030] The second semiconductor layer 6b is also electrically isolated at the same location where the source electrode 4a and the drain electrode 4b are electrically isolated. Furthermore, a first passivation layer 7 made of silicon oxide (SiO2), silicon nitride (SiNx), or the like is formed to cover the TFT 31 and the gate insulating layer 3, and an insulating layer 8 made of acrylic resin or the like is formed to cover the first passivation layer 7.

[0031] Stacked on insulating layer 8 are a lower electrode layer 9 composed of a metal such as Ta, Nd, W, Ti, Mo, Al, Cr, or Ag, or an alloy thereof; a lower impurity semiconductor layer 10 composed of n+-type a-Si or other materials; an intrinsic semiconductor layer 11 composed of intrinsic Si (I-type Si) or other materials; an upper impurity semiconductor layer 12 composed of p+-type a-Si or other materials; and an upper electrode layer 13 composed of a transparent electrode such as indium tin oxide (ITO). The lower electrode layer 9, lower impurity semiconductor layer 10, intrinsic semiconductor layer 11, upper impurity semiconductor layer 12, and upper electrode layer 13 form a PIN-type photodiode, serving as a light detection element 30. This PIN-type photodiode performs photoelectric conversion on light 33 incident on the intrinsic semiconductor layer 11 from the upper impurity semiconductor layer 12 and upper electrode layer 13 sides.

[0032] The light detection element 30 includes: a first light detection element 30a included in a pixel unit 40 located within an active region 50 on the substrate 1 and used for light detection, among the plurality of pixel units 40; and a second light detection element 30b included in a pixel unit 40b located within a non-active region 51 on the substrate 1 and surrounding the active region 50 and not used for light detection, among the plurality of pixel units 40. For convenience of description, reference numerals for components located within the active region 50 are suffixed with "a," while reference numerals for components located within the non-active region 51 are suffixed with "b." The suffixes a and b are omitted for general reference. The pixel unit 40b in the non-active region 51 has the same structure as the pixel unit 40a in the active region 50, and therefore, description thereof is omitted.

[0033] Figure 4A : is a cross-sectional view showing a simplified structure of the first light detecting element 30a arranged in the effective area 50. Figure 4B This is a cross-sectional view that simplified illustrates the structure of the second light detecting element 30b disposed in the inactive region 51. The first light detecting element 30a comprises, on the insulating layer 8 of the substrate 1, a first lower electrode layer 9a formed of a metal or alloy; a first lower impurity semiconductor layer 10a disposed on the first lower electrode layer 9a and located inside the first lower electrode layer 9a in a plan view, and comprising a first impurity semiconductor; a first intrinsic semiconductor layer 11a disposed on the first lower impurity semiconductor layer 10a; a first upper impurity semiconductor layer 12a disposed on the first intrinsic semiconductor layer 11a and comprising a second impurity semiconductor; and a first upper electrode layer 13a disposed on the first upper impurity semiconductor layer 12a.

[0034] The second light detecting element 30 b includes, on the insulating layer 8 of the substrate 1: a second lower electrode layer 9 b formed of a metal or an alloy; a second lower impurity semiconductor layer 10 b arranged on and covering the second lower electrode layer 9 b, and including a first impurity semiconductor; a second intrinsic semiconductor layer 11 b arranged on the second lower impurity semiconductor layer 10 b; a second upper impurity semiconductor layer 12 b arranged on the second intrinsic semiconductor layer 11 b, and including a second impurity semiconductor; and a second upper electrode layer 13 b arranged on the second upper impurity semiconductor layer 12 b.

[0035] Figure 5A 1 is a diagram for conceptually explaining the steps of forming the first lower impurity semiconductor layer 10 a , the first intrinsic semiconductor layer 11 a , and the first upper impurity semiconductor layer 12 a in the first light detecting element 30 a . Figure 5B This figure illustrates the steps for forming the second lower impurity semiconductor layer 10b, the second intrinsic semiconductor layer 11b, and the second upper impurity semiconductor layer 12b in the second light detecting element 30b, the structure that forms the basis of the present disclosure. During the manufacturing process of the first and second light detecting elements 30a and 30b, the first and second lower electrode layers 9a and 9b are formed, for example, by sputtering, and the first and second lower impurity semiconductor layers 10a and 10b are formed by a thin film formation method such as CVD (Chemical Vapor Deposition). The thickness of the first lower electrode layer 9a and the second lower electrode layer 9b is approximately 30 nm to 500 nm, the thickness of the first lower impurity semiconductor layer 10a and the second lower impurity semiconductor layer 10b is approximately 30 nm to 200 nm, the thickness of the first intrinsic semiconductor layer 11a and the second intrinsic semiconductor layer 11b is approximately 500 nm to 2000 nm, the thickness of the first upper impurity semiconductor layer 12a and the second upper impurity semiconductor layer 12b is approximately 5 nm to 50 nm, and the thickness of the first upper electrode layer 13a and the second upper electrode layer 13b is approximately 30 nm to 100 nm.

[0036] The first and second photodetecting elements 30a and 30b are fabricated as follows. The first and second lower electrode layers 9a and 9b are stacked on the insulating layer 8. These layers are then dry-etched to form the desired patterns. The first and second lower electrode layers 9a and 9b are made of the same material and are therefore stacked simultaneously.

[0037] Next, the first lower impurity semiconductor layer 10a, the first intrinsic semiconductor layer 11a, and the first upper impurity semiconductor layer 12a are sequentially stacked on the insulating layer 8 and the first lower electrode layer 9a. The second lower impurity semiconductor layer 10b, the second intrinsic semiconductor layer 11b, and the second upper impurity semiconductor layer 12b are sequentially stacked on the second lower electrode layer 9b. The first lower impurity semiconductor layer 10a, the first intrinsic semiconductor layer 11a, and the first upper impurity semiconductor layer 12a are then etched into a desired pattern using dry etching. Furthermore, the second lower impurity semiconductor layer 10b, the second intrinsic semiconductor layer 11b, and the second upper impurity semiconductor layer 12b are also etched into a desired pattern using dry etching. The first lower impurity semiconductor layer 10a and the second lower impurity semiconductor layer 10b are stacked simultaneously because they are made of the same material. The first intrinsic semiconductor layer 11 a and the second intrinsic semiconductor layer 11 b are also stacked at the same time, and the first upper impurity semiconductor layer 12 a and the second upper impurity semiconductor layer 12 b are also stacked at the same time.

[0038] Next, the first upper electrode layer 13a is stacked on the insulating layer 8 and on the stack of the first lower electrode layer 9a, the first lower impurity semiconductor layer 10a, the first intrinsic semiconductor layer 11a, and the first upper impurity semiconductor layer 12a (first stack), and the second upper electrode layer 13b is stacked on the stack of the second lower electrode layer 9b, the second lower impurity semiconductor layer 10b, the second intrinsic semiconductor layer 11b, and the second upper impurity semiconductor layer 12b (second stack). In addition, since the first upper electrode layer 13a and the second upper electrode layer 13b contain the same material, they are stacked at the same time. Finally, the first upper electrode layer 13a and the second upper electrode layer 13b are etched by dry etching to form the desired pattern. Thus, as shown in FIG. Figure 5A As shown in FIG. 1 , the first lower electrode layer 9a is formed so that its outer periphery is exposed to the outside. In contrast, the second lower electrode layer 9b is formed so that its outer periphery is buried in the second lower impurity semiconductor layer 10b. Figure 4B As shown, the second lower electrode layer 9 b is formed to be covered with the second lower impurity semiconductor layer 10 b .

[0039] Alternatively, the first light detecting element 30a and the second light detecting element 30b are manufactured as follows. First, the first lower electrode layer 9a and the second lower electrode layer 9b, the first lower impurity semiconductor layer 10a and the second lower impurity semiconductor layer 10b, the first intrinsic semiconductor layer 11a and the second intrinsic semiconductor layer 11b, the first upper impurity semiconductor layer 12a and the second upper impurity semiconductor layer 12b, and the first upper electrode layer 13a and the second upper electrode layer 13b are stacked on the insulating layer 8. Thereafter, the outer peripheries of the first lower impurity semiconductor layer 10a and the second lower impurity semiconductor layer 10b, the first intrinsic semiconductor layer 11a and the second intrinsic semiconductor layer 11b, the first upper impurity semiconductor layer 12a and the second upper impurity semiconductor layer 12b, and the first upper electrode layer 13a and the second upper electrode layer 13b are removed by dry etching. Thus, as Figure 5A As shown in FIG. 1 , the first lower electrode layer 9a is formed so that its outer periphery is exposed to the outside. In contrast, the second lower electrode layer 9b is formed so that its outer periphery is buried in the second lower impurity semiconductor layer 10b. Figure 4B As shown, the second lower electrode layer 9 b is formed to be covered with the second lower impurity semiconductor layer 10 b .

[0040] like Figure 5B As shown, in the structured light detection device that forms the basis of the present disclosure, the dry etching process for the second intrinsic semiconductor layer 11b included in the pixel portion 40 located in the non-active region 51 has a low etching rate. Furthermore, after the first intrinsic semiconductor layer 11a and first lower impurity semiconductor layer 10a of the pixel portion 40 in the active region 50, where the etching rate is high, are etched, the etching rate further decreases in the first lower electrode layer 9a in the active region and the pixel portion 40 in the non-active region. This results in etching residues in the second lower impurity semiconductor layer 10b and the second intrinsic semiconductor layer 11b. In the light detection device of this embodiment, since the second lower electrode layer 9b is covered by the second lower impurity semiconductor layer 10b, etching is no longer concentrated in the second lower electrode layer 9b. As a result, etching is concentrated in the pixel portion 40 in the non-active region 51 near the active region 50, and etching of the pixel portion 40 in the non-active region 51 farther from the active region 50 is no longer insufficient. That is, etching of the entire pixel portion in the non-effective region is uniform, thereby preventing etching residues from forming in the second lower impurity semiconductor layer and the second intrinsic semiconductor layer, and suppressing a decrease in yield in the photodetection device manufacturing process.

[0041] Dry etching is a type of etching method that is often used to etch semiconductor materials such as silicon (Si). Reactive ion etching, which uses plasma to ionize gas and generate radicals to perform etching, can be used as a dry etching method.

[0042] Reactive ion etching is a method in which plasma (discharge) is generated within a chamber, and the object being processed is etched using ions, free radicals, and other active species generated by ionizing the gas inside. In reactive ion etching, the frequency of the high-frequency electric field that generates the plasma is 13.56 MHz or 2.54 GHz. In addition, the raw material gas (raw material gas for etching) that generates the plasma is tetrafluorosilane (SiF4), hexafluorosilane (SiF6), carbon tetrafluoride (CF4), sulfur hexafluoride (SF6), trifluoromethane (CHF3), etc. When etching silicon materials such as polycrystalline silicon and amorphous silicon, fluorine-based gases such as tetrafluorosilane (SiF4) can be used.

[0043] There are basically four types of materials that can be etched: oxides such as silicon dioxide (SiO2) and tetraethoxysilane (Si(OC2H5)4), nitrides such as silicon nitride (SiN), silicon-based materials such as silicon (Si), tungsten silicon (WSi), molybdenum silicon (MoSi), and titanium silicon (TiSi), and metal-based materials such as aluminum (Al), aluminum alloys, titanium (Ti), titanium nitride (TiN), tungsten titanium (TiW), tungsten (W), copper (Cu), platinum (Pt), and gold (Au).

[0044] Free radicals are chemical species that contain free atoms and free molecules with unpaired electrons generated by the ionization of gases. They are active species with extremely high reactivity and instability. Atoms and molecules usually have electrons in pairs (shared electron pairs) in the same orbit, but due to the movement of electrons caused by strong energy such as heat and light, the cleavage of chemical coupling, etc., unpaired electrons are produced, becoming free radicals. Since free radicals do not form shared electron pairs, they are extremely unstable and highly reactive molecular species. For example, when silicon dioxide (SiO2) is dry-etched by carbon tetrafluoride (CF4), a reaction characterized by the following reaction formula (1) occurs.

[0045] SiO2+CF3+F*(fluoride ion radical)→SiF4+CO x …(1)

[0046] While this reaction continues, silicon dioxide (SiO 2 ) is continuously etched.

[0047] During the dry etching process within the chamber, the reason why radicals concentrate in the lower electrode layer 9 located in the active area 50 in the center of the chamber is believed to be as follows. There are two types of ionic radicals: cation radicals and anion radicals. Cation radicals are ionic radicals that have lost one electron from the highest occupied molecular orbital (HOMO), while anion radicals are chemical species that have an excess of one electron in the lowest unoccupied molecular orbital (LOMO).

[0048] Fluoride ion radicals are ion radicals that have detached an electron from their atomic highest occupied molecular orbital (HOMO). They chemically stabilize by extracting electrons from the material being processed. Specifically, when the material being processed is a metal, such as lower electrode layer 9, fluoride ion radicals concentrate on the metal electrode because they extract free electrons from the metal or form electron pairs with free electrons to chemically stabilize the material. In other words, this is because the metal electrode functions as a ground conductor due to the fluoride ion radicals.

[0049] Therefore, when manufacturing the light detection device of this embodiment, the second lower electrode layer 9b of the pixel portion 40 located in the non-active region 51 is covered by the second lower impurity semiconductor layer 10b and the second intrinsic semiconductor layer 11b. Figure 4B As shown, there is no direct contact with the etching atmosphere gas.

[0050] Furthermore, the first photodetecting element 30a included in the pixel portion 40 located in the active area 50 has the first lower impurity semiconductor layer 10a disposed on the first lower electrode layer 9a, inward of the first lower electrode layer 9a in a plan view. Specifically, the outer periphery of the first lower electrode layer 9a protrudes from the first lower impurity semiconductor layer 10a and the first intrinsic semiconductor layer 11a, becoming exposed. Thus, when the first lower electrode layer 9a is covered by the first lower impurity semiconductor layer 10a and the first intrinsic semiconductor layer 11a, the formation of cracks or other damaged portions due to internal stress in the first lower impurity semiconductor layer 10a and the first intrinsic semiconductor layer 11a near the end faces of the first lower electrode layer 9a during fabrication of the photodetecting device can be prevented. Cracks or other damaged portions are caused by increased internal stress in the first lower impurity semiconductor layer 10a and the first intrinsic semiconductor layer 11a near the end faces of the first lower electrode layer 9a. Cracks or other damaged portions can hinder photoelectric conversion. Therefore, it is possible to prevent the photoelectric conversion efficiency of the light detection device from being reduced.

[0051] Furthermore, in the second light detecting element 30b of the present embodiment, the second lower electrode layer 9b is covered by the second lower impurity semiconductor layer 10b. Therefore, even if cracks or other damaged portions occur in the second lower impurity semiconductor layer 10b and the second intrinsic semiconductor layer 11b near the end face of the second lower electrode layer 9b during manufacture of the light detecting device, no problem will arise because the second light detecting element 30b included in the pixel portion 40 in the non-active region 51 is a so-called dummy light detecting element.

[0052] In the photodetecting device of this embodiment, the second intrinsic semiconductor layer 11b can cover the second lower impurity semiconductor layer 10b. In this case, since the ends of the second lower electrode layer 9b are covered by the second lower impurity semiconductor layer 10b and the second intrinsic semiconductor layer 11b, etching can be more effectively prevented from concentrating on the ends of the second lower electrode layer 9b. Furthermore, since the end faces of the second lower electrode layer 9b are covered by the second lower impurity semiconductor layer 10b and the second intrinsic semiconductor layer 11b, most of the electric lines of force emerging from the end faces of the second lower electrode layer 9b pass through the second lower impurity semiconductor layer 10b and the second intrinsic semiconductor layer 11b. As a result, a decrease in the photoelectric conversion efficiency of the second photodetecting element 30b can be suppressed.

[0053] Furthermore, the end face of the first lower electrode layer 9a can be a gently inclined surface with an acute angle (less than 90°) formed with the surface of the substrate 1 on which the pixel portion 40 is disposed (denoted as θ1). In this case, the surface area of ​​the protrusion of the first lower electrode layer 9a that protrudes from the first lower impurity semiconductor layer 10a is increased. Therefore, even if etching is concentrated on the protrusion of the first lower electrode layer 9a, the protrusion of the first lower electrode layer 9a can be prevented from becoming excessively smaller or being removed by etching. After the etching process, the protrusion of the first lower electrode layer 9a remains sufficiently, allowing a sufficient electric field to be applied between the first lower electrode layer 9a and the first upper electrode layer 13a. As a result, a decrease in the photoelectric conversion efficiency of the first light detecting element 30a can be suppressed. The angle θ1 can be approximately 80° or less, and can be within a range of approximately 10° to 80°, or even approximately 30° to 60°.

[0054] If the angle θ1 exceeds 80°, the effect of preventing the protrusion of the first lower electrode layer 9a from becoming too small or being removed by etching tends to decrease. If the angle θ1 is less than 10°, the protrusion of the first lower electrode layer 9a tends to be sparsely formed.

[0055] The first lower electrode layer 9a may also contain aluminum. Aluminum is a light metal with high conductivity. Furthermore, when it is ionized, it becomes a trivalent positive ion, with three unpaired electrons in the outermost electron orbital of the atom. Specifically, aluminum generates a large number of free electrons due to temperature increases, photoelectric effects caused by electromagnetic wave irradiation, and the like. As a result, the aforementioned fluorine ion radicals capture free electrons on the surface of the aluminum or form electron pairs with free electrons, thereby enhancing the chemical stabilization effect. Therefore, since fluorine ion radicals tend to concentrate in the first lower electrode layer 9a containing aluminum, the structure disclosed herein is suitable.

[0056] The first lower electrode layer 9a can be made of Al, Al / Ti, Ti / Al / Ti, Mo / Al / Mo, MoNd / AlNd / MoNd, or the like. "Al / Ti" refers to a laminated structure in which a Ti layer is laminated on an Al layer. The first lower electrode layer 9a can be made of duralumin (Al-Cu alloy, Al-Cu-Mg alloy, Al-Zn-Mg-Cu alloy), an aluminum alloy primarily composed of aluminum.

[0057] Furthermore, the end face of the second lower electrode layer 9b can be formed as a gently inclined surface with an acute angle (less than 90°) (denoted by θ2) with the surface of the substrate 1 on which the pixel portion is disposed. In this case, during fabrication of the light detection device, the formation of cracks or other damage in the second lower impurity semiconductor layer 10b and the second intrinsic semiconductor layer 11b near the end face of the second lower electrode layer 9b can be suppressed. The second light detection element 30b included in the pixel portion 40 of the non-active region 51 is a so-called dummy light detection element that is not used for light detection, but may be used as an inspection light detection element. In other words, the pixel portion 40 of the non-active region 51 can also serve as an inspection pixel portion for indirectly inspecting the pixel portion 40 of the active region 50. In this case, the end face of the second lower electrode layer 9b can be formed as a gently inclined surface with an acute angle (θ2). The angle θ2 can be approximately 80° or less, and further approximately 60° or less.

[0058] To more effectively suppress the formation of the aforementioned cracks and other damage, angle θ2 may be 45° or less, more preferably 3° to 30°, and even more preferably 5° to 20°. If θ2 exceeds 45°, the aforementioned cracks and other damage tend to form more easily. Furthermore, if θ2 is less than 3°, the end portion of the second lower electrode layer 9b tends to be sparsely formed.

[0059] The second lower electrode layer 9b may also contain aluminum. Aluminum is a light metal with high conductivity. Furthermore, when it is ionized, it becomes a trivalent positive ion, with three unpaired electrons in the outermost electron orbital of the atom. In other words, aluminum generates a large number of free electrons due to temperature increases, photoelectric effects caused by electromagnetic wave irradiation, and the like. As a result, the aforementioned fluorine ion radicals are more effective in chemically stabilizing the aluminum by capturing free electrons on the surface or forming electron pairs with free electrons. Therefore, since fluorine ion radicals tend to concentrate in the second lower electrode layer 9b containing aluminum, the structure disclosed herein is suitable.

[0060] The first upper electrode layer 13a and the second upper electrode layer 13b can be transparent conductive layers. Transparent conductive layers can include materials such as indium tin oxide (ITO) and indium zinc oxide (IZO). In this case, light is preferably incident on the first upper electrode layer 13a and the second upper electrode layer 13b from the outside.

[0061] The inactive area 51 may be a structure that surrounds the entire periphery of the active area 50. In this case, since there are no defects in the dummy pixel portion 40b located in the inactive area 51, the dummy pixel portion 40b can be effectively used as a pixel portion for inspection. That is, the entire pixel portion 40 existing in the active area 50 corresponding to the dummy pixel portion 40b located in the inactive area 51 can be inspected without omission. The number of columns of the dummy pixel portions 40b in the circumferential direction contained in the inactive area 51 may be one column or multiple columns. In the case of multiple columns, the presence or absence of defects in the dummy pixel portion 40b located in the inactive area 51 can be more effectively inspected. In the case of multiple columns, the number of columns may be about 2 to 3 columns.

[0062] Alternatively, the number of columns of dummy pixel portions 40b in the circumferential direction included in the inactive region 51 may be limited to one or two, with the plurality of dummy pixel portions 40b added in a column partially located outside the column. For example, the plurality of dummy pixel portions 40b added may be located at locations on the input side of a scanning signal or on the signal detection side where more rigorous inspection is desired.

[0063] The following structure is possible: on the substrate 1, the first lower electrode layer 9a and the second lower electrode layer 9b are located on the same layer, the first lower impurity semiconductor layer 10a and the second lower impurity semiconductor layer 10b are located on the same layer, the first intrinsic semiconductor layer 11a and the second intrinsic semiconductor layer 11b are located on the same layer, the first upper impurity semiconductor layer 12a and the second upper impurity semiconductor layer 12b are located on the same layer, and the first upper electrode layer 13a and the second upper electrode layer 13b are located on the same layer. In this case, the first photodetector element 30a and the second photodetector element 30b can be manufactured using the same manufacturing process. This shortens manufacturing time and enables defect-free photodetection devices to be manufactured with a high yield. Furthermore, it is easy to fabricate the pixel portion 40 in the non-active region 51 with a substantially identical structure to the pixel portion 40 in the active region 50. As a result, the pixel portion 40 in the non-active region 51 can be easily used as an inspection pixel portion for indirectly inspecting the pixel portion 40 in the active region 50.

[0064] Figure 6 is a cross-sectional view of a second light detecting element 30b1 included in a light detecting device according to another embodiment of the present disclosure. Figure 7 This is a cross-sectional view showing the structure of the pixel section 40 having the active region 50 of the first light detecting element 30a1. The same reference numerals are used to designate parts corresponding to those in the above-described embodiment, and repeated descriptions are omitted. Regarding the light detecting device of this embodiment, the pixel section 40 disposed in the inactive region 51 is configured in the manufacturing process. Figure 6 The second light detecting element 30b1 shown in FIG. 1 replaces the second light detecting element 30b. The first light detecting element 30a1 is similar to the first light detecting element 30a of the embodiment described above and has Figure 7 structure.

[0065] Right now, Figure 6 The light detection device of the present embodiment shown, in addition to the structure of the light detection device of the aforementioned embodiment, further includes a passivation layer 35, which is located between the outer periphery of the second lower electrode layer 9b and the outer periphery of the second lower impurity semiconductor layer 10b, and protrudes from the outer peripheries of the second upper impurity semiconductor layer 12b, the second intrinsic semiconductor layer 11b, and the second lower impurity semiconductor layer 10b onto the insulating layer 8 of the substrate 1.

[0066] Such a passivation layer 35 is made of silicon oxide (SiO 2 ), silicon nitride (SiN x ), etc., covers at least a portion of the insulating layer 8 and the second lower electrode layer 9 b , and can prevent the generation of etching residues in the dry etching process.

[0067] The light detection device of the present disclosure, including the various embodiments described above, is used, for example, in a radiation image forming device. The radiation image forming device has a structure including a scintillator that converts the wavelength of radiation into light and the light detection device of the present disclosure described above. For example, the light detection device arranges a large number of pixel units 40 in a matrix arranged in the row direction and the column direction. According to the above structure, an accurate radiation image of a subject such as a person can be obtained. The scintillator in the radiation image forming device of the present disclosure includes CsI:Tl, GOS (Gd2O2S:Tb), etc., and converts the wavelength of radiation such as X-rays, gamma rays, and alpha rays irradiated on the subject into light. Furthermore, it is used in a radiation image forming device using an indirect conversion method in which the light 33 emitted from the scintillator is photoelectrically converted into electric charge by the light detection device of the present disclosure to obtain image information. The scintillator including CsI:Tl is formed by vapor-depositing a radiation-sensitive layer (scintillator layer) on a metal substrate including Al (aluminum), etc. Furthermore, for example, a radiation image forming device can be constructed by disposing a scintillator on the light source side of the light 33 in the light detection device of the present disclosure and bonding them together using bonding means such as an adhesive.

[0068] As described above, the photodetection device disclosed herein includes a scintillator that converts the wavelength of radiation into light at a position opposite the surface where the first and second photodetection elements 30a and 30b are located on the substrate 1. The first and second photodetection elements 30a and 30b can be photodetection devices that detect light output from the scintillator. Furthermore, the photodetection device disclosed herein can be a medical photodetection device that emits x-rays (X-rays) with a wavelength of 1 pm to 10 nm, a so-called x-ray device. In this case, a x-ray device with fewer defects and a high manufacturing yield can be provided.

[0069] Furthermore, the electrical image information obtained by the radiation image forming device is converted into digital data through AD (Analog to Digital) conversion, converted into a digital image through an image processor, and displayed on a display unit such as a liquid crystal display (LCD) for use in image diagnosis, image analysis, etc.

[0070] The present disclosure can be implemented as follows.

[0071] The light detection device disclosed in the present invention includes: a substrate; a plurality of pixel portions arranged in a row direction and a column direction on the substrate and configured in a matrix shape; a first light detection element, which is provided in a pixel portion located in an effective area used for light detection on the substrate among the plurality of pixel portions; and a second light detection element, which is provided in a pixel portion located in an ineffective area used for light detection on the substrate that surrounds the effective area among the plurality of pixel portions, the first light detection element having: a first lower electrode layer, which is arranged on the substrate; a first lower impurity semiconductor layer, which is arranged on the inner side of the first lower electrode layer when viewed from above, and includes a first impurity semiconductor; a first intrinsic semiconductor layer, which is The second light detecting element comprises: a first lower impurity semiconductor layer disposed on the first intrinsic semiconductor layer; a first upper impurity semiconductor layer disposed on the first intrinsic semiconductor layer and including a second impurity semiconductor; and a first upper electrode layer disposed on the first upper impurity semiconductor layer. The second light detecting element comprises: a second lower electrode layer disposed on the substrate; a second lower impurity semiconductor layer disposed on the second lower electrode layer to cover the second lower electrode layer and including the first impurity semiconductor; a second intrinsic semiconductor layer disposed on the second lower impurity semiconductor layer; a second upper impurity semiconductor layer disposed on the second intrinsic semiconductor layer and including the second impurity semiconductor; and a second upper electrode layer disposed on the second upper impurity semiconductor layer.

[0072] According to the photodetection device disclosed herein, during the manufacturing process of the photodetection device, the etching rate of the second intrinsic semiconductor layer included in the pixel portion located in the non-active region is low during the dry etching process. Therefore, even after etching the first intrinsic semiconductor layer and the first lower impurity semiconductor layer in the pixel portion of the active region, where the etching rate is high, etching is concentrated on the first lower electrode layer in the active region. The etching rate of the pixel portion in the non-active region is further reduced. Furthermore, since the second lower electrode layer is covered by the second lower impurity semiconductor layer, etching is no longer concentrated on the second lower electrode layer. As a result, etching is concentrated on the pixel portion in the non-active region near the active region, while etching of the pixel portion in the non-active region farther from the active region is no longer insufficient. In other words, etching is uniform throughout the pixel portion in the non-active region. Therefore, etching residue is prevented from forming in the second lower impurity semiconductor layer and the second intrinsic semiconductor layer, thereby suppressing a decrease in the yield of the photodetection device during the manufacturing process.

[0073] While the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the aforementioned embodiments, and various modifications and improvements can be made without departing from the spirit of the present disclosure. It goes without saying that all or part of the aforementioned embodiments can be appropriately combined within the scope of non-inconsistency.

[0074] Explanation of symbols

[0075] 1 substrate

[0076] 2 gate lines

[0077] 3 Gate insulation layer

[0078] 4a Source electrode

[0079] 4b Drain electrode

[0080] 5. Etch stop layer

[0081] 6a 1st semiconductor layer

[0082] 6b Second semiconductor layer

[0083] 7. First passivation layer

[0084] 8 Insulation layer

[0085] 9 Lower electrode layer

[0086] 9a 1st lower electrode layer

[0087] 9b Second lower electrode layer

[0088] 10 Lower impurity semiconductor layer

[0089] 10a First lower impurity semiconductor layer

[0090] 10b Second lower impurity semiconductor layer

[0091] 11 Intrinsic semiconductor layer

[0092] 11a First intrinsic semiconductor layer

[0093] 11b Second intrinsic semiconductor layer

[0094] 12 Upper impurity semiconductor layer

[0095] 12a First upper impurity semiconductor layer

[0096] 12b Second upper impurity semiconductor layer

[0097] 13 Upper electrode layer

[0098] 13a 1st upper electrode layer

[0099] 13b Second upper electrode layer

[0100] 14. Second passivation layer

[0101] 15. Third electrode layer

[0102] 16 Bias line

[0103] 17 3rd passivation layer

[0104] 20 Lower contact hole

[0105] 20a Insulating filling material

[0106] 21 recess

[0107] 22 Upper contact hole

[0108] 30 light detection element

[0109] 30a First light detection element

[0110] 30b, 30b1 Second light detection element

[0111] 31 TFT

[0112] 32 source signal lines

[0113] 33 Light

[0114] 35 passivation layer

[0115] 40 pixel unit

[0116] 40b Dummy pixel portion

[0117] 48 Gate signal line drive circuit

[0118] 50 effective areas

[0119] 51 Invalid area.

Claims

1. A light detection device, comprising: substrate; A plurality of pixel portions are arranged in a matrix in row and column directions on the substrate; a first light detecting element provided in a pixel portion located within an effective region for light detection on the substrate among the plurality of pixel portions; and The second light detecting element is provided in a pixel portion located in an inactive region surrounding the active region and not used for light detection on the substrate, among the plurality of pixel portions. The first light detecting element includes a first lower electrode layer, a first lower impurity semiconductor layer, a first intrinsic semiconductor layer, a first upper impurity semiconductor layer, and a first upper electrode layer. The first lower electrode layer is arranged on the substrate, The first lower impurity semiconductor layer is arranged on the first lower electrode layer and inside the first lower electrode layer in a plan view, and includes a first impurity semiconductor. The first intrinsic semiconductor layer is arranged on the first lower impurity semiconductor layer, The first upper impurity semiconductor layer is disposed on the first intrinsic semiconductor layer and includes a second impurity semiconductor. The first upper electrode layer is arranged on the first upper impurity semiconductor layer, The second light detecting element includes a second lower electrode layer, a second lower impurity semiconductor layer, a second intrinsic semiconductor layer, a second upper impurity semiconductor layer, and a second upper electrode layer. The second lower electrode layer is arranged on the substrate, The second lower impurity semiconductor layer is arranged on the second lower electrode layer to cover the second lower electrode layer and includes the first impurity semiconductor. The second intrinsic semiconductor layer is arranged on the second lower impurity semiconductor layer, The second upper impurity semiconductor layer is disposed on the second intrinsic semiconductor layer and includes the second impurity semiconductor. The second upper electrode layer is arranged on the second upper impurity semiconductor layer.

2. The light detection device according to claim 1, wherein The second intrinsic semiconductor layer covers the second lower impurity semiconductor layer.

3. The light detection device according to claim 1 or 2, wherein: The end surface of the first lower electrode layer is formed as a gently inclined surface that forms an acute angle with the surface of the substrate on which the pixel portion is disposed.

4. The light detection device according to claim 3, wherein The angle of the end face of the first lower electrode layer is 80° or less.

5. The light detection device according to any one of claims 1 to 4, wherein The first lower electrode layer includes aluminum.

6. The light detection device according to any one of claims 1 to 5, wherein The end surface of the second lower electrode layer is formed as a gently inclined surface that forms an acute angle with the surface of the substrate on which the pixel portion is disposed.

7. The light detection device according to claim 6, wherein The angle of the end face of the second lower electrode layer is 45° or less.

8. The light detection device according to any one of claims 1 to 7, wherein The second lower electrode layer includes aluminum.

9. The light detection device according to any one of claims 1 to 8, wherein The first upper electrode layer and the second upper electrode layer are transparent conductor layers.

10. The light detection device according to any one of claims 1 to 9, wherein The light detection device further comprises: The passivation layer is located between the outer periphery of the second lower electrode layer and the outer periphery of the second intrinsic semiconductor layer, and protrudes from the outer periphery of the second intrinsic semiconductor layer onto the substrate.

11. The light detection device according to any one of claims 1 to 10, wherein The ineffective area is set to surround the entire periphery of the effective area.

12. The light detection device according to any one of claims 1 to 11, wherein On the substrate, the first lower electrode layer and the second lower electrode layer are located in the same layer, the first lower impurity semiconductor layer and the second lower impurity semiconductor layer are located in the same layer, the first intrinsic semiconductor layer and the second intrinsic semiconductor layer are located in the same layer, the first upper impurity semiconductor layer and the second upper impurity semiconductor layer are located in the same layer, and the first upper electrode layer and the second upper electrode layer are located in the same layer.

13. The light detection device according to any one of claims 1 to 11, wherein A scintillator for converting the wavelength of radiation into light is provided at a position on the substrate facing the surface where the first photodetection element and the second photodetection element are located. The first light detecting element and the second light detecting element detect light output from the scintillator.

14. The light detection device according to claim 13, wherein The radiation is xentang rays with a wavelength of 1 pm to 10 nm.

15. The light detection device according to any one of claims 1 to 14, wherein The pixel portion located in the non-active region is a pixel portion for inspection that indirectly inspects the pixel portion located in the active region.

16. The light detection device according to any one of claims 1 to 15, wherein The substrate is flexible.

Images