IMAGE ELEMENT AND METHOD FOR MANUFACTURING AN IMAGE ELEMENT AND LIGHT DETECTION DEVICE

Abstract

An imaging element in an embodiment of the present disclosure comprises a first electrode and a second electrode, a third electrode arranged opposite the first and second electrodes, a photoelectric conversion layer provided between the first and third electrodes and between the second and third electrodes, an insulating layer provided between the first electrode and the photoelectric conversion layer and between the second electrode and the photoelectric conversion layer, having an opening over the second electrode, a first layer provided between the photoelectric conversion layer and the insulating layer and formed at least over the first electrode, and a second layer formed at least over the second electrode.while it is electrically coupled to the second electrode via the opening and differs from the first layer in at least one aspect of material composition, crystallinity, impurity concentration, or constituent element.

Description

Technical area

[0001] For example, the present disclosure relates to an imaging member using an organic material and a method for manufacturing the same, as well as a light detection device. State of the art

[0002] For example, PTL 1 discloses a solid-state imaging device in which a photoelectric conversion film and a semiconductor layer are provided between a first electrode and a second electrode arranged opposite to each other from the first electrode side, and further in which a third electrode covered by an insulating film is provided in the semiconductor layer. Citation listPatent literature

[0003] PTL1: WO2020 / 203249 Summary of the invention

[0004] Meanwhile, for a light detection device used in an imaging device, etc., a captured image is expected to have improved image quality.

[0005] It is desirable to provide an imaging element and a method of manufacturing an imaging element and a light detection device that enable improvement of captured image quality.

[0006] An imaging member according to an embodiment of the present disclosure comprises: a first electrode and a second electrode; a third electrode disposed opposite the first electrode and the second electrode; a photoelectric conversion layer provided between the first electrode and the third electrode and between the second electrode and the third electrode; an insulating layer provided between the first electrode and the photoelectric conversion layer and between the second electrode and the photoelectric conversion layer, the insulating layer having an opening above the second electrode;and a semiconductor layer comprising a first layer and a second layer, wherein the first layer is provided between the photoelectric conversion layer and the insulating layer and is formed at least over the first electrode, and the second layer is formed at least over the second electrode while being electrically coupled to the second electrode via the opening and differs from the first layer in at least one of material composition, crystallinity, contained impurity concentration, or constituent element.;

[0007] An embodiment of the present disclosure provides a method for manufacturing an imaging member. The imaging member includes a first electrode and a second electrode, a third electrode disposed opposite the first electrode and the second electrode, a photoelectric conversion layer provided between the first electrode and the third electrode and between the second electrode and the third electrode, an insulating layer provided between the first electrode and the photoelectric conversion layer and between the second electrode and the photoelectric conversion layer, the insulating layer having an opening above the second electrode, and a semiconductor layer including a first layer and a second layer.The first layer is provided between the photoelectric conversion layer and the insulating layer and is formed at least over the first electrode, and the second layer is formed at least over the second electrode while being electrically coupled to the second electrode via the opening and differing from the first layer in at least one of material composition, crystallinity, contained impurity concentration, or constituent element. The method comprises: forming the first layer using a physical vapor deposition method; and forming the second layer using an atomic layer deposition method.

[0008] A light sensing device according to an embodiment of the present disclosure includes one or a plurality of imaging elements according to an embodiment of the present disclosure for each plurality of pixels.

[0009] In an imaging member according to an embodiment of the present disclosure, a method for manufacturing an imaging member according to an embodiment of the present disclosure, and a light detection device according to an embodiment of the present disclosure, a semiconductor layer is provided which comprises a first layer and a second layer, wherein between an insulating layer covering the first electrode from a first electrode and a second electrode and having an opening above the second electrode, and a photoelectric conversion layer, the first layer is formed at least above the first electrode, and the second layer is formed at least above the second electrode while being electrically coupled to the second electrode via the opening and different from the first layer in at least one of material composition, crystallinity,contained impurity concentration or constituent element. This improves the charge carrier transport property to the second electrode. Short description of the drawings Fig. 1 is a schematic sectional view illustrating an example of a configuration of an imaging element according to an embodiment of the present disclosure. Fig. 2 is a schematic plan view illustrating an example of a pixel configuration of an imaging device using the Fig. 1 illustrated imaging element. Fig. 3A is a schematic sectional view illustrating an example of a configuration of a photoelectric conversion section used in Fig. 1 is illustrated. Fig. Fig. 3B is a schematic sectional view illustrating another example of the configuration of the photoelectric conversion section used in Fig. 1 is illustrated. Fig. Figure 4 illustrates an energy level corresponding to a line AA located in Fig. 3A is illustrated. Fig. Figure 5 illustrates an energy level corresponding to a line BB, which is Fig. 3A is illustrated. Fig. Figure 6 illustrates an energy level corresponding to a line CC located in Fig. 3A is illustrated. Fig. Figure 7 is an equivalent circuit diagram of the imaging element used in Fig. 1 is illustrated. Fig. Fig. 8 is a schematic view illustrating an arrangement of a transistor included in a lower electrode and a control section in the imaging element shown in Fig. 1 is illustrated. Fig. 9A is a sectional view describing a method of manufacturing the imaging element shown in Fig. 1 is illustrated. Fig. 9B is a sectional view illustrating a process based on Fig. 9A follows. Fig. Figure 9C is a sectional view illustrating a process based on Fig. 9B follows. Fig. 9D is a sectional view illustrating a process based on Fig. 9C follows. Fig. 9E is a sectional view illustrating a process performed on Fig. 9D follows. Fig. Figure 9F is a sectional view illustrating a process based on Fig. 9E follows. Fig. 9G is a sectional view illustrating a process performed on Fig. 9F follows. Fig. 9H is a sectional view illustrating a process based on Fig. 9G follows. Fig. 9I is a sectional view illustrating a process based on Fig. 9H follows. Fig. Figure 9J is a sectional view illustrating a process based on Fig. 9I follows. Fig. 9K is a sectional view illustrating a process that occurs on Fig. 9J follows. Fig. 10 is a timing chart illustrating an example of operation of the imaging element shown in Fig. 1 is illustrated. Fig. 11 is a schematic sectional view illustrating a configuration of a photoelectric conversion section according to Modification Example 1 of the present disclosure. Fig. 12A is a sectional view illustrating a method of manufacturing an imaging member used in Fig. 11 is illustrated. Fig. 12B is a sectional view illustrating a process based on Fig. 12A follows. Fig. Figure 12C is a sectional view illustrating a process based on Fig. 12B follows. Fig. 12D is a sectional view illustrating a process based on Fig. 12C follows. Fig. 13 is a schematic sectional view illustrating a configuration of a photoelectric conversion section according to Modification Example 2 of the present disclosure. Fig. 14A is a sectional view illustrating a method of manufacturing an imaging member used in Fig. 13 is illustrated. Fig. 14B is a sectional view illustrating a process based on Fig. 14A follows. Fig. 14C is a sectional view illustrating a process based on Fig. 14B follows. Fig. Figure 14D is a sectional view illustrating a process based on Fig. 14C follows. Fig. 14E is a sectional view illustrating a process performed on Fig. 14D follows. Fig. 14F is a sectional view illustrating a process based on Fig. 14E follows. Fig. 14G is a sectional view illustrating a process performed on Fig. 14F follows. Fig. 14H is a sectional view illustrating a process that occurs on Fig. 14G follows. Fig. 14I is a sectional view illustrating a process performed on Fig. 14H follows. Fig. 15 is a schematic sectional view illustrating a configuration of a photoelectric conversion section according to Modification Example 3 of the present disclosure. Fig. 16A is a sectional view describing a method of manufacturing an imaging member used in Fig. 15 is illustrated. Fig. 16B is a sectional view illustrating a process based on Fig. 16A follows. Fig. 16C is a sectional view illustrating a process based on Fig. 16B follows. Fig. 16D is a sectional view illustrating a process based on Fig. 16C follows. Fig. 16E is a sectional view illustrating a process performed on Fig. 16D follows. Fig. 16F is a sectional view illustrating a process based on Fig. 16E follows. Fig. 16G is a sectional view illustrating a process performed on Fig. 16F follows. Fig. 16H is a sectional view illustrating a process based on Fig. 16G follows. Fig. 17A is a schematic sectional view illustrating an example of a configuration of an imaging element according to Modification Example 4 of the present disclosure. Fig. 17B is a schematic plan view illustrating an example of a pixel configuration of an imaging device including the imaging element shown in Fig. 17A is illustrated. Fig. 18A is a schematic sectional view illustrating an example of a configuration of an imaging element according to Modification Example 5 of the present disclosure. Fig. 18B is a schematic plan view illustrating an example of a pixel configuration of an imaging device including the imaging element shown in Fig. 18A is illustrated. Fig. 19 is a schematic sectional view illustrating an example of a configuration of an imaging element according to Modification Example 6 of the present disclosure. Fig. 20 is a block diagram illustrating a configuration of an imaging device using, as a pixel, the imaging element shown in Fig. 1 is illustrated, etc. Fig. 21 is a block diagram illustrating an example of a configuration of an electronic device using the imaging device shown in Fig. 20 is illustrated. Fig. 22A is a schematic view illustrating an example of an overall configuration of a light detection system using the imaging device shown in Fig. 20 is illustrated. Fig. 22B illustrates an example of a circuit configuration of the light detection system used in Fig. 22A is illustrated. Fig. 23 is a view showing an example of a schematic configuration of an endoscopic surgery system. Fig. 24 is a block diagram showing an example of a functional configuration of a camera head and a camera control unit (CCU). Fig. 25 is a block diagram showing an example of a schematic configuration of a vehicle control system. Fig. 26 is a diagram of assistance in explaining an example of installation positions of an external vehicle information detecting section and an imaging section. Modes for carrying out the invention

[0010] Hereinafter, some embodiments of the present disclosure will be described in detail with reference to the drawings. The embodiments described below are specific examples of the present disclosure, and the present disclosure is not limited to the following embodiments. In addition, the arrangement, dimensions, dimensional relationships, and the like of components in the present disclosure are not limited to the embodiment illustrated in each drawing. Note that the description will be given in the following order. 1. Embodiment (Example of an imaging element comprising two types of semiconductor layers having at least one difference and provided over a readout electrode and a storage electrode, respectively) 1-1. Imaging Element Configuration 1-2. Method for manufacturing the imaging element 1-3. Signal acquisition operation by the imaging element 1-4. Functions and Effects 2. Modification examples 2-1. Modification Example 1 (another example of the layout of two types of semiconductor layers) 2-2. Modification Example 2 (another example of the layout of two types of semiconductor layers) 2-3. Modification Example 3 (another example of the layout of two types of semiconductor layers) 2-4. Modification Example 4 (An Example of an Imaging Element That Diffuses Light Using a Color Filter) 2-5. Modification Example 5 (Another example of an imaging element that scatters light using a color filter) 2-6. Modification Example 6 (An example of an imaging element in which a plurality of photoelectric conversion sections are stacked) 3. Application examples 4. Practical applications <1. Embodiment>

[0011] Fig. 1 illustrates a sectional configuration of an imaging element (imaging element 10) according to an embodiment of the present disclosure. Fig. Figure 2 schematically illustrates an example of a planar configuration of the imaging element 10 shown in Fig. 1 is illustrated, and Fig. 1 illustrates a section along a line II, which in Fig. 2 is illustrated. Fig. 3A is an enlarged view schematically illustrating an example of a sectional configuration of a main portion (photoelectric conversion portion 20) of the imaging element 10 shown in Fig. 1 is illustrated. Fig. Fig. 3B is an enlarged view schematically illustrating another example of the sectional configuration of the main portion (photoelectric conversion portion 20) of the imaging element 10 shown in Fig. 1. For example, the imaging element 10 is included in a pixel (unit pixel P) that is repeatedly arranged in an array in a pixel section 1A of an imaging device (for example, imaging device 1, see Fig. 20), such as a CMOS image sensor (CMOS = Complementary Metal Oxide Semiconductor), which is used, for example, in an electronic device such as a digital still camera or video camera.

[0012] In the imaging member 10 of the present embodiment, the photoelectric conversion section 20 provided on a semiconductor substrate 30 includes, between a lower electrode 21 including a readout electrode 21A and a storage electrode 21B, and a photoelectric conversion layer 25, a semiconductor layer 23 including a first layer 23A and a second layer 23B that are different from each other across the readout electrode 21A and the storage electrode 21B, respectively. The difference between the first layer 23A and the second layer 23B is in at least one of material composition, crystallinity, contained impurity concentration, or constituent element. An insulating layer 22 having an opening 22H on the readout electrode 21A is provided between the lower electrode 21 and the semiconductor layer 23.The first layer 23A is provided over the storage electrode 21B via the insulating layer 22, and the second layer 23B is provided over the sense electrode 21A while being electrically coupled to the sense electrode 21A via the opening 22H. The sense electrode 21A corresponds to a specific example of a "second electrode" of the present disclosure, and the storage electrode 21B corresponds to a specific example of a "first electrode" of the present disclosure. In addition, the first layer 23A corresponds to a specific example of a "first layer" of the present disclosure, and the second layer 23B corresponds to a specific example of a "second layer" of the present disclosure. (1-1. Configuration of the imaging element)

[0013] For example, the imaging element 10 is of a so-called longitudinal spectral type, in which a photoelectric conversion section 20 and two photoelectric conversion regions 32B and 32R are stacked in a longitudinal direction. The photoelectric conversion section 20 is provided on a back surface (first surface 30A) of the semiconductor substrate 30. The photoelectric conversion regions 32B and 32R are embedded in the semiconductor substrate 30 and stacked in a thickness direction of the semiconductor substrate 30.

[0014] The photoelectric conversion section 20 and the photoelectric conversion regions 32B and 32R selectively detect light having different wavelength ranges from each other and perform photoelectric conversion. For example, the photoelectric conversion section 20 detects a green (G) signal. The photoelectric conversion regions 32B and 32R detect blue (B) and red (R) signals, respectively, depending on a difference in absorption coefficient. This allows the imaging element 10 to detect a variety of color signals in one pixel without using a color filter.

[0015] Note that the present embodiment describes a case where an electron is read out as a signal charge from an electron-hole pair (exciton) generated by photoelectric conversion (a case where an n-type semiconductor region is used as a photoelectric conversion layer). Additionally, "+ (plus)" appended to "p" or "n" in the figure indicates a high concentration of a p-type or n-type impurity.

[0016] For example, on one surface (second surface 30B) of the semiconductor substrate 30, a floating diffusion layer FD1 (region 36B in the semiconductor substrate 30), an FD2 (region 37C in the semiconductor substrate 30), an FD3 (region 38C in the semiconductor substrate 30), transfer transistors Tr2 and Tr3, an amplifier transistor (modulation element) AMP, a reset transistor RST, and a selection transistor SEL are provided. A multilayer wiring layer 40 is further provided on the second surface 30B of the semiconductor substrate 30 via a gate insulating layer 33. For example, the multilayer wiring layer 40 has a configuration in which wiring layers 41, 42, and 43 are stacked within an insulating layer 44.In an edge around the semiconductor substrate 30, namely, the edge region 1B around the pixel portion 1A, a vertical drive circuit 111, a column signal processing circuit 112, a horizontal drive circuit 113, an output circuit 114, a control circuit 115, and an input / output terminal 116 or the like, as described later, are provided.

[0017] Note that in the drawing, the first surface 30A side of the semiconductor substrate 30 is illustrated as a light incident side S1, and the second surface 30B side is illustrated as a wiring layer side S2.

[0018] In the photoelectric conversion section 20, between the lower electrode 21 and the upper electrode 26, which are arranged opposite to each other, a semiconductor layer 23, a protective layer 24, and a photoelectric conversion layer 25 formed using an organic material are stacked in this order from the lower electrode 21 side. In the semiconductor layer 23, as described above, the first layer 23A and the second layer 23B, which have a difference in at least one of material composition, crystallinity, contained impurity concentration, or constituent element, are provided over the readout electrode 21A and the storage electrode 21B, respectively. The photoelectric conversion layer 25 includes a p-type semiconductor and an n-type semiconductor and has a bulk heterojunction structure within the layer.The bulk heterojunction structure includes a p / n junction surface formed as a result of mixing the p-type semiconductor and the n-type semiconductor.

[0019] The photoelectric conversion section 20 further includes the insulating layer 22 between the lower electrode 21 and the semiconductor layer 23. For example, the insulating layer 22 is provided over an entire surface of the pixel section 1A and also has the opening 22H on the readout electrode 21A included in the lower electrode 21. The readout electrode 21A is electrically coupled to the semiconductor layer 23 via this opening 22H. The first layer 23A in the semiconductor layer 23 is provided over the storage electrode 21B via the insulating layer 22. The second layer 23B in the semiconductor layer 23 is provided over the readout electrode 21A, for example, along the opening 22H from a side surface to a lower surface thereof, and is electrically coupled to the readout electrode 21A at the lower surface.

[0020] It should be noted that although Fig. 1 illustrates an example in which the semiconductor layer 23, the protective layer 24, the photoelectric conversion layer 25, and the upper electrode 26 are formed separately for each imaging element 10, for example, the semiconductor layer 23, the protective layer 24, the photoelectric conversion layer 25, and the upper electrode 26 may be provided as a continuous layer shared by a plurality of imaging elements 10.

[0021] For example, an insulating layer 27 and an interlayer insulating layer 28 are stacked between the first surface 30A of the semiconductor substrate 30 and the lower electrode 21. In the insulating layer 27, a fixed charge layer (fixed charge layer) 27A and a dielectric layer 27B having an insulating property are stacked in this order from the semiconductor substrate 30 side.

[0022] The photoelectric conversion regions 32B and 32R enable longitudinal dispersion of light by utilizing a wavelength difference of light absorbed according to a depth of incident light in the semiconductor substrate 30 comprising a silicon substrate, and each have a pn junction in a predetermined region of the semiconductor substrate 30.

[0023] A through electrode 34 is provided between the first surface 30A and the second surface 30B of the semiconductor substrate 30. The through electrode 34 is electrically coupled to the readout electrode 21A, and via the through electrode 34, for example, the photoelectric conversion section 20 is coupled to a gate Gamp of an amplifier transistor AMP and to a source / drain region 36B of the reset transistor RST (reset transistor Tr1rst), which also serves as the floating diffusion FD1. This allows the imaging element 10 to satisfactorily transfer a carrier (here, an electron) generated in the photoelectric conversion section 20 provided on the first surface 30A side of the semiconductor substrate 30 to the second surface 30B side of the semiconductor substrate 30 via the through electrode 34, thereby improving a characteristic.

[0024] The through electrode 34 has a lower end coupled to a wiring (coupling section 41A) in a wiring layer 41, and the coupling section 41A is coupled to the gate Gamp of the amplifier transistor AMP via a lower first contact 45. The coupling section 41A is coupled to the floating diffusion FD1 (region 36B) via, for example, a lower second contact 46. The through electrode 34 has an upper end coupled to the sense electrode 21A via, for example, a pad 39A and an upper first contact 39D.

[0025] A protective layer 51 is provided over the photoelectric conversion section 20. For example, wiring 52 is provided in the protective layer 51 to electrically couple the upper electrode 26 and the peripheral circuit section 130 around the pixel section 1A. Furthermore, an optical element, such as a planarization layer (not shown) or an on-chip lens 54, is provided over the protective layer 51.

[0026] In the imaging element 10 of the present embodiment, incident light to the photoelectric conversion section 20 from the light incident side S1 is absorbed by the photoelectric conversion layer 25. An exciton generated thereby moves to an interface between an electron donor and an electron acceptor included in the photoelectric conversion layer 25 and undergoes exciton separation, that is, dissociates into an electron and a hole. Each carrier generated here (the electron and the hole) is transported to another electrode by diffusion due to a difference in carrier concentration or by an internal electric field due to a difference in work function between an anode (for example, the upper electrode 26) and a cathode (for example, the lower electrode 21) to be detected as a photoelectric current.In addition, it is also possible to control a transport direction of the electron and the hole by applying an electric potential between the lower electrode 21 and the upper electrodes 26.

[0027] The configuration, material, etc. of each section are described in detail below.

[0028] The photoelectric conversion section 20 is an organic photoelectric conversion element that generates an exciton by absorbing, for example, green light corresponding to all or part of a selective wavelength range (for example, 450 nm or more to 650 nm or less).

[0029] For example, the lower electrode 21 includes the readout electrode 21A, the storage electrode 21B, and the transfer electrode 21C. The readout electrode 21A, the storage electrode 21B, and the transfer electrode 21C are stacked in the insulating layer 22, for example, in an order of the readout electrode 21A, the storage electrode 21B, and the transfer electrode 21C from the semiconductor substrate 30 side in one section. Specifically, the readout electrode 21A, the storage electrode 21B, and the transfer electrode 21C are each provided per unit pixel P. As shown in Fig. 2, for example, the readout electrode 21A is provided at one of four corners of the unit pixel P. The storage electrode 21B is provided around the readout electrode 21A, for example, in a higher layer than the readout electrode 21A. Although in Fig. 2, the transfer electrode 21C is provided to surround the readout electrode 21A, for example, between the readout electrode 21A and the storage electrode 21B in both the plan view and the sectional view.

[0030] The readout electrode 21A is designed to transfer the carrier generated in the photoelectric conversion layer 25 to the floating diffusion FD1. The readout electrode 21A is coupled to the floating diffusion FD1 via, for example, the upper first contact 39D, the pad 39A, the through electrode 34, the coupling portion 41A, and the lower second contact 46.

[0031] For example, the storage electrode 21B is intended to accumulate an electron as a signal charge in the semiconductor layer 23 from the carrier generated in the photoelectric conversion layer 25. The storage electrode 21B is provided per unit pixel P directly opposite the light-receiving surfaces of the photoelectric conversion regions 32B and 32R formed in the semiconductor substrate 30, in an area covering these light-receiving surfaces. It is preferable that the storage electrode 21B be larger than the readout electrode 21A, thereby enabling accumulation of a large number of carriers. Independently of the readout electrode 21A, a voltage is applied to the storage electrode 21B via, for example, an upper sixth contact 39L, a pad 39K, an upper fifth contact 39J, a pad 39H, an upper third contact 39F, and a pad 39C.

[0032] The transfer electrode 21C is intended to improve the transfer efficiency of the carrier accumulated above the storage electrode 21B to the readout electrode 21A. Independently of the readout electrode 21A and the storage electrode 21B, a voltage is to be applied to the transfer electrode 21C via, for example, an upper fourth contact 39I, a pad 39G, an upper second contact 39E, and a pad 39B.

[0033] Although in Fig. 1, a shield electrode 21D for dividing each unit pixel P is further provided around the storage electrode 21B. The shield electrode 21D is intended to prevent capacitive coupling between adjacent unit pixels P, and a fixed potential is applied thereto, for example.

[0034] The lower electrode 21 includes a conductive film with light transmittance, such as ITO (indium tin oxide). As a constituent material for the lower electrode 21 other than ITO, a tin oxide (SnO2)-based material with an added dopant or a zinc oxide-based material resulting from adding a dopant to zinc oxide (ZnO) can be used. As the zinc oxide-based material, for example, aluminum zinc oxide (AZO) with aluminum (Al) added as a dopant, gallium zinc oxide (GZO) with gallium (Ga) added, or indium zinc oxide (IZO) with indium (In) added can be used. In addition, IGZO, ITZO, CuI, InSbO4, ZnMgO, CuInO2, MgIn2O4, CdO, ZnSnO3, or the like can be used.

[0035] The insulating layer 22 is intended to electrically separate the storage electrode 21B and the semiconductor layer 23. The insulating layer 22 is provided, for example, on the interlayer insulating layer 28 to cover the lower electrode 21. As described above, the insulating layer 22 has the opening 22H on the readout electrode 21A in the lower electrode 21, and the readout electrode 21A and the semiconductor layer 23 are electrically coupled to each other via this opening 22H. The insulating layer 22 comprises, for example, a single-layer film comprising one kind or a multi-layer film comprising two or more kinds, which are made of silicon oxide (SiO x ), hafnium oxide (HfO x ), aluminum oxide (AlO x ), silicon nitride (SiN x ) and silicon oxynitride (SiON) or the like. The insulating layer 22 has a thickness of, for example, 20 nm to 500 nm.

[0036] The semiconductor layer 23 is intended to accumulate the carrier generated in the photoelectric conversion layer 25. As described above, the semiconductor layer 23 is provided between the lower electrode 21 and the photoelectric conversion layer 25. Specifically, the semiconductor layer 23 is provided on the insulating layer 22 and over a side surface and a bottom surface of the opening 22H formed on the readout electrode 21A, and is electrically coupled to the readout electrode 21A in the bottom surface of the opening 22H. The semiconductor layer 23 includes the first layer 23A and the second layer 23B, which have a difference. The first layer 23A and the second layer 23B are provided over the storage electrode 21B and the readout electrode 21A, respectively, and the second layer 23B is electrically coupled to the readout electrode 21A via the opening 22H.The difference between the first layer 23A and the second layer 23B is described below.

[0037] For example, it is preferable that the first layer 23A, which is provided over the storage electrode 21B and in which the carrier (in this case, the electron) generated in the photoelectric conversion layer 25 is accumulated, has fewer defects that trap a carrier. For the second layer 23B, which is provided over the readout electrode 21A and along the side surface and the bottom surface of the opening 22H of the insulating layer 22, it is important that it has embeddability.

[0038] As described above, it is possible for the semiconductor layer 23 to achieve both low trapping over the storage electrode 21B and embeddability in the opening 22H by causing the first layer 23A and the second layer 23B to have a difference in at least one of material composition, crystallinity, contained impurity concentration, or constituent element.

[0039] For example, the first layer 23A and the second layer 23B have crystalline properties different from each other. Specifically, for example, the first layer 23A has crystallinity, and the second layer 23B has amorphousness. For example, an impurity having a different concentration is added to each of the first layer 23A and the second layer 23B, and for example, it is preferable that the impurity concentration of the first layer 23A be lower than that of the second layer 23B, for example, one-tenth or less. Here, the impurity contained in the first layer 23A and the second layer 23B is, for example, carbon (C).

[0040] It is possible to form the semiconductor layer 23 using, for example, an oxide semiconductor material including at least one type of element selected from indium (In), gallium (Ga), silicon (Si), zinc (Zn), aluminum (Al), and tin (Sn). In the present embodiment, an electron in the carrier generated in the photoelectric conversion layer 25 is used as a signal charge. This makes it possible to form the semiconductor layer 23 using an n-type oxide semiconductor material. Specifically, as a constituent material for the semiconductor layer 23, it is possible to mention IGZO, Ga2O3, GZO, IZO, ITO, InGaAlO, InGaSiO, or the like.For example, in a case where the first layer 23A is formed using the above oxide semiconductor material, it is preferable that an amount of In contained in the first layer 23A is larger than the amount of In contained in the second layer 23B, and it is preferable that an amount of Ga contained in the first layer 23A is smaller than the amount of Ga contained in the second layer 23B. In addition, among the oxide semiconductor materials described above, it is preferable that the second layer 23B contains Al.

[0041] It is possible to form the first layer 23A, for example, using a physical vapor deposition (PVD) method. It is possible to form the second layer 23B, for example, using an atomic layer deposition (ALD) method. The semiconductor layer 23 has a thickness of, for example, 10 nm to 300 nm.

[0042] The protective layer 24 is intended to prevent oxygen desorption from the oxide semiconductor material included in the semiconductor layer 23. For example, it is possible to form the protective layer 24 using a metal oxide containing at least one type of element selected from tantalum (Ta), titanium (Ti), vanadium (V), niobium (Nb), tungsten (W), zirconium (Zr), hafnium (Hf), scandium (Sc), yttrium (Y), lanthanum (La), gallium (Ga), and magnesium (Mg). In particular, as a constituent material for the protective layer 24, for example, it is possible to mention tantalum oxide (Ta2O5), titanium oxide (TiO2), vanadium oxide (V2O5), niobium oxide (Nb2O5), tantalum oxide (W2O3), zirconium oxide (ZrO2), hafnium oxide (HfO2), scandium oxide (Sc2O3), yttrium oxide (Y2O3), lanthanum oxide (La2O3), gallium oxide (Ga2O3), and magnesium oxide (MgO).For example, the protective layer 24 having a thickness of one atomic layer is effective, and it is preferable that the protective layer 24 has a thickness of, for example, 0.5 nm or more and 10 nm or less.

[0043] As in Fig. As illustrated in Figure 3A, the protective film 29 may be sandwiched between the second layer 23B, which is provided above the sense electrode 21A and along the side surface and the bottom surface of the opening 22H, and the protective layer 24. The protective film 29 is intended to prevent oxygen desorption and comprises, for example, an insulating film such as SiO x or AlO x .

[0044] It should be noted that it is not always necessary to provide the second layer 23B along the side surface and the bottom surface of the opening 22H, and as shown in Fig. For example, as illustrated in Figure 3B, the second layer 23B may be provided to fill the opening 22H. In this case, the protective film 29 is omitted.

[0045] The photoelectric conversion layer 25 converts light energy into electrical energy. The photoelectric conversion layer 25 includes, for example, two or more types of organic materials (a p-type semiconductor material or an n-type semiconductor material), each of which functions as a p-type semiconductor material or an n-type semiconductor material. The photoelectric conversion layer 25 has a junction surface (p / n junction surface) between the p-type semiconductor material and the n-type semiconductor material within the layer. A p-type semiconductor functions relatively as an electron donor (donor), and an n-type semiconductor functions relatively as an electron acceptor (acceptor). The photoelectric conversion layer 25 provides a field in which an exciton generated when light is absorbed is separated into an electron and a hole.In particular, the exciton is separated into an electron and a hole at an interface between the electron donor and the electron acceptor (p / n junction surface).

[0046] Other than the p-type semiconductor material and the n-type semiconductor material, the photoelectric conversion layer 25 may also include a so-called dye material, which is an organic material that photoelectrically converts light having a predetermined wavelength range while transmitting light having a different wavelength range. In a case where the photoelectric conversion layer 25 is formed using three types of organic materials, that is, the p-type semiconductor material, the n-type semiconductor material, and the dye material, it is preferable that the p-type semiconductor material and the n-type semiconductor material have light transmittance in a visible region (for example, 450 nm to 800 nm). The photoelectric conversion layer 25 has a thickness of, for example, 50 nm to 500 nm.

[0047] As the organic material contained in the photoelectric conversion layer 25, for example, a quinacridone derivative, a naphthalene derivative, an anthracene derivative, a phenanthrene derivative, a tetracene derivative, a pyrene derivative, a perylene derivative, and a fluoranthene derivative can be mentioned. The photoelectric conversion layer 25 comprises a combination of two or more types of the above-described organic materials. The above-described organic materials function as a p-type semiconductor or an n-type semiconductor depending on the combination.

[0048] Note that the organic material contained in the photoelectric conversion layer 25 is not particularly limited. For example, in addition to the above-described organic materials, it is possible to use a polymer of phenylenevinylene, fluorene, carbazole, indole, pyrene, pyrrole, picoline, thiophene, acetylene, and diacetylene, or the like, or a derivative thereof.Alternatively, it is possible to use a metal complex dye, a cyanine dye, a merocyanine dye, a phenylxanthene dye, a triphenylmethane dye, a rhodacyanine dye, a xanthene dye, a macrocyclic azaazulene dye, an azulene dye, a naphthoquinone dye, an anthraquinone dye, a condensed aromatic polycyclic compound such as pyrene, a chain compound containing condensed aromatic or heterocyclic compounds, quinoline having a squarylium group and a croconitumetin group as a bonding chain, two nitrogen-containing heterocycles such as benzothiazole and benzoxazole, or a cyanine-type dye bonded through a squarylium group and a croconitumetin group, or the like.Note that the metal complex dye can be a dithiol metal complex dye, a metal phthalocyanine dye, a metal porphyrin dye, or a ruthenium complex dye. Among these, the ruthenium complex dye is particularly preferred, but the material is not limited to the above-described.

[0049] Fig. Fig. 4 illustrates an energy level of the readout electrode 21A, the second layer 23B and the first layer 23A, which corresponds to a line AA shown in Fig. 3A is illustrated. Fig. Fig. 5 illustrates an energy level of the storage electrode 21B, the insulating layer 22, the first layer 23A, the protective layer 24 and the photoelectric conversion layer 25, which corresponds to a line BB shown in Fig. 3A is illustrated. Fig. Fig. 6 illustrates an energy level of the readout electrode 21A, the second layer 23B, the protective film 29, the protective layer 24 and the photoelectric conversion layer 25, which corresponds to a line CC shown in Fig. 3A. Note that a direction away from a vacuum level is defined to indicate greater positive energy.

[0050] For example, it is preferable that an energy level (Ec_v) at a lowest end of a conduction band of the second layer 23B is equal to an energy level (Ec_h) at a lowest end of a conduction band of the first layer 23A or lower than the energy level (Ec_h) at the lowest end of the conduction band of the first layer 23A (Ec_v ≥ Ec_h). It is preferable that the energy level (Ec_h) at the lowest end of the conduction band of the first layer 23A is equal to or lower than an energy level (Ec_b) at a lowest end of a conduction band of the protective layer 24, and that the energy level (Ec_b) at the lowest end of the conduction band of the protective layer 24 is equal to or lower than an LUMO (Ec_O) of the photoelectric conversion layer (Ec_h ≥ Ec_b ≥ Ec_O).It is preferable that the energy level at the lowest end of the conduction band of the second layer 23B (Ec_v) is shallower than an energy level (Ec_pas) at a lowest end of a conduction band of the protective film 29, that the energy level (Ec_b) at the lowest end of the conduction band of the protective film 29 is shallower than the LUMO (Ec_O) of the photoelectric conversion layer, and that the LUMO (Ec_O) of the photoelectric conversion layer is shallower than the energy level (Ec_b) at the lowest end of the conduction band of the protective layer 24 (Ec_v > Ec_pas, Ec_pas < Ec_O < Ec_b).

[0051] The upper electrode 26 includes a conductive film having light transmittance similar to the upper electrode 26, and includes, for example, ITO (indium tin oxide). Other than this ITO, a tin oxide (SnO2)-based material with a dopant added thereto or a zinc oxide-based material resulting from adding a dopant to zinc oxide (ZnO) can be used as a constituent material for the upper electrode 26. As the zinc oxide-based material, for example, aluminum zinc oxide (AZO) with aluminum (Al) added as a dopant, gallium zinc oxide (GZO) with gallium (Ga) added thereto, and indium zinc oxide (IZO) with indium (In) added thereto are possible examples. In addition to this, IGZO, ITZO, CuI, InSbO4, ZnMgO, CuInO2, MgIn2O4, CdO, ZnSnO3 or the like can also be used.The upper electrode 26 can be separate for each pixel or can be formed as a common electrode for each pixel. The upper electrode 26 has a thickness of, for example, 10 nm to 200 nm.

[0052] Note that the photoelectric conversion section 20 may include another layer between the lower electrode 21 and the photoelectric conversion layer 25 (for example, between the protective layer 24 and the photoelectric conversion layer 25) and between the photoelectric conversion layer 25 and the upper electrode 26. For example, in the photoelectric conversion section 20, the protective layer 24, a buffer layer that also serves as an electron blocking film, the photoelectric conversion layer 25, a buffer layer that also serves as a hole blocking film, and a work function adjusting layer or the like may be stacked in order from the lower electrode 21 side.In addition, for example, the photoelectric conversion layer 25 may have a pin-bulk heterojunction configuration in which a p-type junction layer, a layer including a p-type semiconductor and an n-type semiconductor (i-layer), and an n-type junction layer are stacked.

[0053] The insulating layer 27 covers the first surface 30A of the semiconductor substrate 30 to reduce an interface level with the semiconductor substrate 30 and suppress generation of dark current from the interface with the semiconductor substrate 30. In addition, the insulating layer 27 extends from the first surface 30A of the semiconductor substrate 30 to a side surface of an opening 34H (see Fig. 9B), in which the through electrode 34 penetrating the semiconductor substrate 30 is formed. For example, the insulating layer 27 has a stacked configuration of the fixed charge layer 27A and the dielectric layer 27B.

[0054] The fixed charge layer 27A may be a film with a positive fixed charge or a film with a negative fixed charge. As a constituent material for the fixed charge layer 27A, it is preferable to form the fixed charge layer 27A using a semiconductor material or a conductive material with a wider band gap than that of the semiconductor substrate 30. This makes it possible to suppress the generation of dark current at the interface of the semiconductor substrate 30. As the constituent material for the fixed charge layer 27A, it is possible to use, for example, hafnium oxide (HfOx), aluminum oxide (AlO x ), zirconium oxide (ZrO x ), tantalum oxide (TaO x ), titanium oxide (TiO x ), lanthanum oxide (LaO x ), praseodymium oxide (PrOx), cerium oxide (CeO x ), neodymium oxide (NdO x ), promethium oxide (PmO x ), samarium oxide (SmO x ), europium oxide (EuO x), gadolinium oxide (GdOx), terbium oxide (TbOx), dysprosium oxide (DyOx), holmium oxide (HoO x ), thulium oxide (TmOx), ytterbium oxide (YbO x ), lutetium oxide (LuO x ), yttrium oxide (YO x ), hafnium nitride (HfNx), aluminum nitride (AlNx), hafnium oxynitride (HfO x N y ) and aluminum oxynitride (AlO x N y ) or the like.

[0055] The dielectric layer 27B is intended to prevent light reflection caused by a difference in refractive index between the semiconductor substrate 30 and the interlayer insulating layer 28. As a constituent material for the dielectric layer 27B, it is preferable to use a material having a refractive index between the refractive index of the semiconductor substrate 30 and the refractive index of the interlayer insulating layer 28. As the constituent material for the dielectric layer 27B, for example, silicon oxide, TEOS, silicon nitride, and silicon oxynitride (SiON) or the like can be mentioned.

[0056] For example, the interlayer insulating layer 28 comprises a single-layer film comprising one kind selected from silicon oxide, silicon nitride, and silicon oxynitride, or the like, or a multilayer film comprising two or more kinds thereof.

[0057] For example, the semiconductor substrate 30 comprises an n-type silicon (Si) substrate and has a p-well 31 in a predetermined region.

[0058] The photoelectric conversion regions 32B and 32R each include a photodiode (PD) having a pn junction in a predetermined region of the semiconductor substrate 30, thereby enabling longitudinal dispersion of light by utilizing the fact that a wavelength of light absorbed in the Si substrate varies depending on the depth of the incident light. For example, the photoelectric conversion region 32B selectively detects blue light and accumulates a signal charge corresponding to blue, and is arranged at a depth enabling efficient photoelectric conversion of blue light. For example, the photoelectric conversion region 32R selectively detects red light and accumulates a signal charge corresponding to red, and is arranged at a depth enabling efficient photoelectric conversion of red light.Note that blue (B) and red (R) are colors corresponding to a wavelength range of 450 nm to 495 nm and a wavelength range of 620 nm to 750 nm, respectively. It is sufficient to allow each of the photoelectric conversion regions 32B and 32R to detect light in all or part of a corresponding one of the wavelength ranges.

[0059] The photoelectric conversion region 32B includes, for example, a p+ region intended to be a hole accumulation layer and an n-type region intended to be an electron accumulation layer. The photoelectric conversion region 32R includes, for example, a p+ region intended to be a hole accumulation layer and an n-type region intended to be an electron accumulation layer (with a pnp laminate configuration). The n-type region in the photoelectric conversion region 32B is coupled to a vertical-type transfer transistor Tr2. The p+ region in the photoelectric conversion region 32B is bent along the transfer transistor Tr2, resulting in the p+ region of the photoelectric conversion region 32R.

[0060] For example, the gate insulating layer 33 comprises a single-layer film comprising one kind selected from silicon oxide, silicon nitride, and silicon oxynitride, or the like, or a multi-layer film comprising two or more kinds thereof.

[0061] The through electrode 34 is provided between the first surface 30A and the second surface 30B of the semiconductor substrate 30 and serves as a connector for coupling the photoelectric conversion section 20 to the gate Gamp of the amplifier transistor AMP and the floating diffusion FD1, while serving as a transmission path for the carrier generated in the photoelectric conversion section 20. A reset gate Grst of the reset transistor RST is arranged adjacent to the floating diffusion FD1 (a source / drain region 36B of the reset transistor RST). This allows the reset transistor RST to reset the carrier accumulated in the floating diffusion FD1.

[0062] The pads 39A and 39B, the upper first contact 39D, the upper second contact 39E, the lower first contact 45, the lower second contact 46 and the wiring 52 are formed using, for example, a doped silicon material such as PDAS (Phosphorus Doped Amorphous Silicon) or a metallic material such as aluminum (Al), tungsten (W), titanium (Ti), cobalt (Co), hafnium (Hf) or tantalum (Ta).

[0063] The protective layer 51 and the on-chip lens 54 comprise a material with light transmittance, such as a single-layer film comprising one of silicon oxide, silicon nitride, and silicon oxynitride, or a stacked film comprising two or more types thereof. This protective layer 51 has a thickness of, for example, 100 nm to 30,000 nm.

[0064] For example, a light-shielding film 53 may be provided within the protective layer 51. For example, the light-shielding film 53 is provided together with the wiring 52 in the protective layer 51 to cover a region of the readout electrode 21A that is in direct contact with the semiconductor layer 23, but not over at least the storage electrode 21B. It is possible to form the light-shielding film 53 using, for example, tungsten (W), aluminum (Al), an alloy of Al and copper (Cu), or the like.

[0065] Fig. Figure 7 is an equivalent circuit diagram of the imaging element 10 shown in Fig. 1 is illustrated. Fig. Fig. 8 schematically illustrates an arrangement of each transistor included in the lower electrode 21 and a control section of the imaging element 10 shown in Fig. 1 is illustrated.

[0066] The reset transistor RST (reset transistor TR1rst) is designed to reset the carrier transferred from the photoelectric conversion section 20 to the floating diffusion FD1 and includes, for example, a MOS transistor. Specifically, the reset transistor TR1rst includes the reset gate Grst, a channel formation region 36A, and source / drain regions 36B and 36C. The reset gate Grst is coupled to a reset line RST1, and a source / drain region 36B of the reset transistor TR1rst also serves as the floating diffusion FD1. Another source / drain region 36C included in the reset transistor TR1rst is coupled to a power line VDD.

[0067] The amplifier transistor AMP (amplifier transistor TR1amp) is a modulation element that modulates an amount of electric charge generated in the photoelectric conversion section 20 to a voltage, and includes, for example, a MOS transistor. Specifically, the amplifier transistor AMP includes a gate Gamp, a channel formation region 35A, and source / drain regions 35B and 35C. The gate Gamp is coupled to the sense electrode 21A and a source / drain region 36B (floating diffusion FD1) of the reset transistor TR1rst via the lower first contact 45, the coupling section 41A, the lower second contact 46, and the through electrode 34 or the like. In addition, a source / drain region 35B shares a region with another source / drain region 36C included in the reset transistor TR1rst and is coupled to the power line VDD.

[0068] The selection transistor SEL (selection transistor TR1sel) includes a gate Gsel, a channel formation region 34A, and source / drain regions 34B and 34C. The gate Gsel is coupled to the selection line SEL1. A source / drain region 34B shares a region with another source / drain region 35C included in the amplifier transistor AMP, and another source / drain region 34C is coupled to the signal line (data output line) VSL1.

[0069] The transfer transistor TR2 (transfer transistor TR2trs) is intended to transfer the signal charge corresponding to blue, which is generated and accumulated in the photoelectric conversion region 32B, to the floating diffusion FD2. Since the photoelectric conversion region 32B is formed at a deep position from the second surface 30B of the semiconductor substrate 30, it is preferable that the transfer transistor TR2trs in the photoelectric conversion region 32B comprise a vertical-type transistor. The transfer transistor TR2trs is coupled to a transfer gate line TG2. The floating diffusion FD2 is provided in the region 37C near a gate Gtrs2 of the transfer transistor TR2trs. The carrier accumulated in the photoelectric conversion region 32B is read out to the floating diffusion FD2 via a transfer channel formed along the gate Gtrs2.

[0070] A transfer transistor TR3 (transfer transistor TR3trs) is designed to transfer the signal charge corresponding to red, generated and accumulated in the photoelectric conversion region 32R, to the floating diffusion FD3, and comprises, for example, a MOS transistor. The transfer transistor TR3trs is coupled to a transfer gate line TG3. A floating diffusion FD3 is provided in the region 38C near a gate Gtrs3 of the transfer transistor TR3trs. The carrier accumulated in the photoelectric conversion region 32R is read out to the floating diffusion FD3 via the transfer channel formed along the gate Gtrs3.

[0071] Further, on the second surface side 30B of the semiconductor substrate 30, a reset transistor TR2rst, an amplifier transistor TR2amp, and a selection transistor TR2sel are provided to be included in the control portion of the photoelectric conversion region 32B. Further, a reset transistor TR3rst, an amplifier transistor TR3amp, and a selection transistor TR3sel are provided to be included in the control portion of the photoelectric conversion region 32R.

[0072] The reset transistor TR2rst includes a gate, a channel formation region, and a source / drain region. The reset transistor TR2rst has a gate coupled to the reset line RST2, and a source / drain region of the reset transistor TR2rst is coupled to the power line VDD. Another source / drain region of the reset transistor TR2rst also serves as the floating diffusion FD2.

[0073] The amplifier transistor TR2amp includes a gate, a channel formation region, and a source / drain region. The gate is coupled to another source / drain region (the floating diffusion FD2) of the reset transistor TR2rst. A source / drain region included in the amplifier transistor TR2amp shares a region with a source / drain region included in the reset transistor TR2rst and is coupled to the power line VDD.

[0074] The selection transistor TR2sel includes a gate, a channel formation region, and a source / drain region. The gate is coupled to a selection line SEL2. A source / drain region included in the selection transistor TR2sel shares a region with another source / drain region included in the amplifier transistor TR2amp. Another source / drain region included in the selection transistor TR2sel is coupled to a signal line (data output line) VSL2.

[0075] The reset transistor TR3rst includes a gate, a channel formation region, and a source / drain region. The reset transistor TR3rst has a gate coupled to a reset line RST3, and a source / drain region included in the reset transistor TR3rst is coupled to the power line VDD. Another source / drain region included in the reset transistor TR3rst also serves as the floating diffusion FD3.

[0076] The amplifier transistor TR3amp includes a gate, a channel formation region, and a source / drain region. The gate is coupled to another source / drain region (the floating diffusion FD3) contained in the reset transistor TR3rst. A source / drain region contained in the amplifier transistor TR3amp shares a region with another source / drain region contained in the reset transistor TR3rst and is coupled to the power line VDD.

[0077] The selection transistor TR3sel includes a gate, a channel formation region, and a source / drain region. The gate is coupled to a selection line SEL3. A source / drain region included in the selection transistor TR3sel shares a region with another source / drain region included in the amplifier transistor TR3amp. Another source / drain region included in the selection transistor TR3sel is coupled to a signal line (data output line) VSL3.

[0078] The reset lines RST1, RST2, and RST3, the select lines SEL1, SEL2, and SEL3, and the transfer gate lines TG2 and TG3 are each coupled to a vertical drive circuit included in a drive circuit. The signal lines (data output lines) VSL1, VSL2, and VSL3 are coupled to the column signal processing circuit 112 included in the drive circuit. (1-2. Method for manufacturing the imaging element)

[0079] For example, it is possible to manufacture the imaging member 10 in the present embodiment as follows.

[0080] Fig. 9A to Fig. 9K illustrate a method for manufacturing the imaging element 10 in process order. First, as shown in Fig. As illustrated in Fig. 9A, the p-well 31 is formed in the semiconductor substrate 30, and the n-type photoelectric conversion regions 32B and 32R, for example, are formed in this p-well 31. A p+ region is formed near the first surface 30A of the semiconductor substrate 30.

[0081] On the second surface 30B of the semiconductor substrate 30, for example, in the same manner as in Fig. 9A illustrates that after forming an n+ region to be the floating diffusions FD1 to FD3, the gate insulating layer 33 and a gate wiring layer 47 including the gate of each of the transfer transistor Tr2, the transfer transistor Tr3, the selection transistor SEL, the amplifier transistor AMP, and the reset transistor RST are formed. Accordingly, the transfer transistor Tr2, the transfer transistor Tr3, the selection transistor SEL, the amplifier transistor AMP, and the reset transistor RST are formed. Furthermore, the multilayer wiring layer 40 including the wiring layers 41 to 43 including the lower first contact 45, the lower second contact 46, the coupling portion 41A, and the insulating layer 44 is formed on the second surface 30B of the semiconductor substrate 30.

[0082] As a substrate for the semiconductor substrate 30, for example, an SOI (silicon on insulator) substrate is used on which the semiconductor substrate 30, an embedded oxide film (not illustrated), and a holding substrate (not illustrated) are stacked. Although in Fig. 9A, the embedded oxide film and the support substrate are bonded to the first surface 30A of the semiconductor substrate 30. After ion implantation, annealing processing is performed.

[0083] Next, a support substrate (not illustrated) or another semiconductor substrate or the like is bonded to the multilayer wiring layer 40 provided on the second surface 30B side of the semiconductor substrate 30 and is vertically inverted. Subsequently, the semiconductor substrate 30 is separated from the embedded oxide film of the SOI substrate and the support substrate to expose the first surface 30A of the semiconductor substrate 30. It is possible to perform the above process using a technique used in a conventional CMOS process, such as ion implantation or a CVD (Chemical Vapor Deposition) method.

[0084] Next, as in Fig. 9B illustrates, for example, the semiconductor substrate 30 is processed by dry etching from the side of the first surface 30A to form the opening 34H, for example, in a ring shape. As shown in Fig. 9B, the opening 34H has a depth to penetrate from the first surface 30A to the second surface 30B of the semiconductor substrate 30 and reach, for example, the coupling portion 41A.

[0085] Subsequently, for example, the charge-fixed layer 27A and the dielectric layer 27B are sequentially formed on the first surface 30A of the semiconductor substrate 30 and the side surface of the opening 34H. For example, it is possible to form the charge-fixed layer 27A by forming a hafnium oxide film or an aluminum oxide film using an atomic layer deposition (ALD) method. It is possible to form the dielectric layer 27B, for example, by forming a silicon oxide film using a plasma CVD method. Next, at a predetermined position on the dielectric layer 27B, for example, pads 39A, 39B, and 39C in which a barrier metal comprising a stacked film of titanium and titanium nitride (Ti / TiN film) and a tungsten film are stacked are formed. This makes it possible to use the pads 39A and 39B as a light-shielding film.Then, the interlayer insulating film 28 is formed on the dielectric layer 27B and on the pads 39A, 39B, and 39C, and the surface of the interlayer insulating film 28 is planarized using a CMP (Chemical Mechanical Polishing) method.

[0086] Then, as in Fig. 9C illustrates that after forming openings 28H1, 28H2 on respective ones of the pads 39A, 39B and 39C, a conductive material such as Al is embedded in these openings 28H1, 28H2 and 28H3 to form the upper first contact 39D, the upper second contact 39E and the upper third contact 39F.

[0087] Next, as in Fig. As illustrated in Figure 9D, a conductive film 21x is formed on the interlayer insulating layer 28 using, for example, a sputtering method, and then patterning is performed using a photolithography technique. Specifically, after forming a photoresist PR at a predetermined position on the conductive film 21x, the conductive film 21x is processed using dry etching or wet etching. Then, as shown in Fig. 9E, the photoresist PR is removed, thereby forming the readout electrode 21A and the pads 39G and 39H. Then, in a similar manner, on the interlayer insulating film 28, a lower layer of the insulating film 22, the upper fourth contact 39I and the upper fifth contact 39J, the transfer electrode 21C and the pad 39K, a middle layer of the insulating film 22, the upper sixth contact 39L, the storage electrode 21B, and an upper layer of the insulating film 22 are sequentially formed.

[0088] Then, as in Fig. 9F, the first layer 23A is formed on the insulating layer 22 using, for example, PVD, and then a hard mask 221 is formed on the first layer 23A. Next, as shown in Fig. 9G illustrates, for example, after forming the opening 22H on the sense electrode 21A using, for example, dry etching, the second layer 23B is formed using, for example, ALD, as in Fig. 9H. Then, after forming the protective film 29 for filling the opening 22H, as shown in Fig. 9I illustrates that the protective film 29 and the hard mask 221 formed on the first layer 23A are ground using a CMP method to expose the first layer 23A, as shown in Fig. 9J illustrates.

[0089] Then, as in Fig. 9K, the protective layer 24 is formed using, for example, ALD. Then, the photoelectric conversion layer 25 and the upper electrode 26 are formed on the protective layer 24. The photoelectric conversion layer 25 is formed using, for example, a vacuum evaporation method. As with the lower electrode 21, the upper electrode 26 is formed using, for example, a sputtering method. Finally, the protective layer 51, which includes the wiring 52 and the light-shielding film 53, and the on-chip lens 54 are provided on the upper electrode 26. Thus, the imaging element 10 shown in Fig. 1 is completed.

[0090] Note that, as described above, in a case where another layer comprising an organic material, such as a buffer layer that also serves as an electron-blocking film, a buffer layer that also serves as a hole-blocking film, a work function adjusting layer, or the like, is formed between the protective layer 24 and the photoelectric conversion layer 25, and between the photoelectric conversion layer 25 and the upper electrode 26, it is preferable to form each layer continuously in a vacuum process (in an integrated vacuum process). In addition, the method for forming the photoelectric conversion layer 25 is not necessarily limited to the technique using a vacuum evaporation method, but, for example, a spin coating technique, a printing technique, or the like may also be used.Further, as a method for forming a transparent electrode (the lower electrode 21 and the upper electrode 26) other than the sputtering method, depending on the material contained in the transparent electrode, it is possible to mention a physical vapor deposition (PVD) method such as a vacuum deposition method, a reactive vapor deposition method, an electron beam deposition method, or an ion plating method, a pyrosol method, a thermal decomposition method of an organometallic compound, a spraying method, a dipping method, and various CVD methods including an MOCVD method, an electroless plating method, and an electroplating method. (1-3. Signal acquisition operation by the imaging element)

[0091] In the imaging element 10, when light enters the photoelectric conversion section 20 via the on-chip lens 54, the light is transmitted through the photoelectric conversion section 20 and the photoelectric conversion regions 32B and 32R in this order to photoelectrically convert green (G), blue (B), and red (R) light for each color in the transmission process. A signal detection operation for each color will be described below. (Detection of the green signal by the photoelectric conversion section 20)

[0092] Of the incident light to the imaging element 10, green light is first selectively detected (absorbed) and photoelectrically converted in the photoelectric conversion section 20.

[0093] The photoelectric conversion section 20 is coupled to the gate g of the amplifier transistor TR1amp and the floating diffusion FD1 via the through electrode 34. Accordingly, an electron is extracted from the lower electrode 21 side of the exciton generated in the photoelectric conversion section 20 and transferred to the second surface 30S2 side of the semiconductor substrate 30 via the through electrode 34 to be accumulated in the floating diffusion FD1. At the same time, the amount of electric charge generated in the photoelectric conversion section 20 is modulated into a voltage by the amplifier transistor TR1amp.

[0094] Additionally, the reset gate Grst of the reset transistor TR1rst is located next to the floating diffusion FD1. Accordingly, the carrier accumulated in the floating diffusion FD1 is reset by the reset transistor TR1rst.

[0095] Since the photoelectric conversion section 20 is coupled not only to the amplifier transistor TR1amp but also to the potential-free diffusion FD1 via the through electrode 34, this facilitates the resetting of the carrier accumulated in the potential-free diffusion FD1 by the reset transistor TR1rst.

[0096] In contrast, in a case where the through electrode 34 is not coupled to the floating diffusion FD1, it becomes difficult to reset the carrier accumulated in the floating diffusion FD1, making it necessary to pull the carrier out by applying a large voltage toward the upper electrode 26. For this reason, there is a possibility of damage to the photoelectric conversion layer 25. In addition, this configuration has difficulties because the structure that allows reset in a short time causes an increase in dark noise and results in a compromise.

[0097] Fig. Figure 10 illustrates an example of operation of imaging element 10. (A) illustrates a potential at storage electrode 21B, (B) illustrates a potential at floating diffusion FD1 (readout electrode 21A), and (C) illustrates a potential at the gate (Gsel) of reset transistor TR1rst. In imaging element 10, a voltage is applied separately to each of readout electrode 21A and storage electrode 21B.

[0098] In the imaging element 10, during an accumulation period, a potential V1 is applied from the drive circuit to the readout electrode 21A, and a potential V2 is applied to the storage electrode 21B. A potential V6 is applied to the transfer electrode 21C. Here, it is assumed that V1>V6 and V2>V6. This causes the carrier (signal charge; electron) generated by photoelectric conversion to be attracted to the storage electrode 21B and accumulated in a region contained in the semiconductor layer 23 and opposite to the storage electrode 21B (accumulation period). Incidentally, a value of the potential at the region contained in the semiconductor layer 23 and opposite to the storage electrode 21B becomes more negative over time as the photoelectric conversion progresses. Note that the hole is supplied from the upper electrode 26 to the drive circuit.

[0099] In the imaging element 10, the reset operation is performed at a later stage in the accumulation period. Specifically, at time t1, the sampling section changes the voltage of the reset signal RST from a low level to a high level. This causes the reset transistor TR1rst in the unit pixel P to turn on, and as a result, the voltage of the floating diffusion FD1 is set to the power supply voltage, and the voltage of the floating diffusion FD1 is reset (reset period).

[0100] After the reset operation is completed, the carrier is read out. Specifically, at time t2, the drive circuit applies a potential V3 to the readout electrode 21A, applies a potential V4 to the storage electrode 21B, and applies a potential V5 to the transfer electrode 21C. Here, it is assumed that the potentials V3, V4, and V5 are V3 > V5 > V4. This causes the carrier accumulated over the storage electrode 21B to move from on the storage electrode 21B to on the transfer electrode 21C and to on the readout electrode 21A in this order to be read out to the floating diffusion FD1. In other words, the carrier accumulated in the semiconductor layer 23 is read out to the control section (transfer period).

[0101] After the readout operation is completed, the drive circuit again applies the potential V1 to the readout electrode 21A and applies the potential V2 to the storage electrode 21B. This causes the carrier generated by photoelectric conversion to be attracted to the storage electrode 21B and accumulated in a region contained in the photoelectric conversion layer 25 and opposite to the storage electrode 21B (accumulation period). (Detection of the blue signal and the red signal by the photoelectric conversion areas 32B and 32R)

[0102] Next, among the light transmitted through the photoelectric conversion section 20, blue light and red light are sequentially absorbed and photoelectrically converted in the photoelectric conversion region 32B and 32R, respectively. In the photoelectric conversion region 32B, an electron corresponding to the incoming blue light is accumulated in an n-type region in the photoelectric conversion region 32B, and the accumulated electron is transferred to the floating diffusion FD2 through the transfer transistor Tr2. Similarly, in the photoelectric conversion region 32R, an electron corresponding to the incoming red light is accumulated in an n-type region in the photoelectric conversion region 32R, and the accumulated electron is transferred to the floating diffusion FD3 through the transfer transistor Tr3. (1-4. Functions and Effects)

[0103] In the imaging member 10 of the present embodiment, the photoelectric conversion portion 20 includes the semiconductor layer 23 between the lower electrode 21, which includes the readout electrode 21A and the storage electrode 21B, and the photoelectric conversion layer 25. The semiconductor layer 23 includes the first layer 23A and the second layer 23B, which are different from each other across the readout electrode 21A and the storage electrode 21B, respectively. The difference between the first layer 23A and the second layer 23B is in at least one of material composition, crystallinity, contained impurity concentration, or constituent element. This will be described below.

[0104] In recent years, as an imaging element included in a CCD image sensor, a CMOS image sensor, or the like, the development of a stacked-type imaging element in which a plurality of photoelectric conversion sections are vertically stacked has been promoted. For example, the stacked-type imaging element has a configuration in which two photoelectric conversion regions, each including a photodiode (PD), are stacked to be included in a silicon (Si) substrate, and a photoelectric conversion layer comprising an organic material is provided over the Si substrate.

[0105] In a stacked-type imaging element, it is necessary to have a configuration for accumulating and transferring the signal charge generated in each photoelectric conversion section. For example, the photoelectric conversion section is enabled to accumulate the signal charge generated in the photoelectric conversion layer by having a configuration in which two electrodes, the first electrode and a charge storage electrode, are provided on one side of a photoelectric conversion region of a pair of electrodes arranged opposite to each other with the photoelectric conversion layer interposed therebetween. In such an imaging device, the signal charge is once accumulated over the charge storage electrode and then transferred to the floating diffusion FD in the Si substrate.This allows the electric charge accumulation section to be completely depleted when exposure begins, thereby erasing the carrier. As a result, it is possible to suppress phenomena such as an increase in kTC noise, a deterioration in random noise, or a deterioration in image quality.

[0106] However, a stacked-type solid-state imaging device also has difficulties. It takes time to transfer the accumulated charge from the charge storage electrode to the readout electrode due to the configuration in which the charge accumulated in the semiconductor layer on the charge storage electrode is once caused to move laterally along the upper surface of the charge storage electrode and then flow into the readout electrode located below the charge storage electrode. For this reason, it is difficult to increase a readout speed for reading a pixel signal from each pixel. In response to these difficulties, a configuration in which the transfer of an electric charge within the semiconductor layer for accumulating electric charge is arranged vertically, as described above, has been proposed.In this proposal, the charge storage electrode is arranged to enable a vertical transfer path of the electric charge in the semiconductor layer stacked under the photoelectric conversion layer.

[0107] Meanwhile, in the semiconductor layer, which plays a role in the accumulation of electric charge, it is important to use a semiconductor film with few traps. It is known that an electron trapped in a trap during the accumulation of electric charge will be released with a delay during the transfer of electric charge and become a noise source as a transfer-delay charge.

[0108] In contrast, in the present embodiment, since the semiconductor layer 23 is provided between the lower electrode 21 and the photoelectric conversion layer 25, the first layer 23A and the second layer 23B are provided with a difference in at least one of material composition, crystallinity, contained impurity concentration, or constituent element. This makes it possible to achieve both low trapping above the storage electrode 21B and embeddability in the opening 22H, thereby improving a carrier transport property to the readout electrode 21A.

[0109] As described above, it is possible for the imaging element 10 of the present embodiment to improve the image quality.

[0110] Additionally, in the imaging element 10 of the present embodiment, the readout electrode 21A and the storage electrode 21B are provided on different layers. Specifically, the storage electrode 21B is provided in a higher layer than the readout electrode 21A, the above-described first layer 23A is provided above the storage electrode 21B, and the above-described second layer 23B is provided above the readout electrode 21A. This makes it possible to perform control to cause the electric charge to be accumulated over the storage electrode 21B even when the electron, which is to be the signal charge, reaches the second layer 23B on the readout electrode 21A, thereby making it possible to reduce electric charge loss. Thus, it is possible to increase an area of ​​the storage electrode 21B.

[0111] Next, some modification examples (Modification Examples 1-6) of the present disclosure will be described. Hereinafter, components similar to those in the above embodiment are denoted by the same reference numerals, and the description thereof will be omitted where appropriate. <2. Modification Examples>(2-1. Modification Example 1)

[0112] Fig. 11 schematically illustrates a sectional configuration of a main portion (photoelectric conversion portion 20A) of an imaging member according to Modification Example 1 of the present disclosure. The photoelectric conversion portion 20A of the present modification example differs from the above embodiment in that the second layer 23B extends over the first layer 23A.

[0113] For example, it is possible to manufacture the photoelectric conversion section 20A of the present modification example as follows.

[0114] As in the above embodiment, as in Fig. 12A, the first layer 23A is formed on the insulating layer 22 using, for example, PVD. Next, as shown in Fig. 12B illustrates that after forming the opening 22H on the sense electrode 21A using, for example, dry etching, the second layer 23B is formed using, for example, ALD. Then, as shown in Fig. 12C illustrates that after forming the protective film 29 to fill the opening 22H, the protective film 29 formed on the first layer 23A is ground using a CMP method to expose the second layer 23B, as shown in Fig. 12D. Then, the protective layer 24, the photoelectric conversion layer 25, and the upper electrode 26 are formed as in the above embodiment. Thus, the imaging member 10 shown in Fig. 11 is completed.

[0115] In this way, in the present modification example, the second layer 23B extends over the first layer 23A to cause the first layer 23A and the second layer 23B to be stacked above the storage electrode 21B. The carrier (electron) generated in the photoelectric conversion layer 25 is accumulated in the semiconductor layer 23 above the storage electrode 21B, but most of the carrier is accumulated in the semiconductor layer 23 near an interface with the insulating layer 22, namely, the first layer 23A. For this reason, there is a small trapping effect on the second layer 23B, and therefore, it is possible to obtain an effect similar to that of the above embodiment. (2-2. Modification Example 2)

[0116] Fig. 13 schematically illustrates a sectional configuration of a main portion (photoelectric conversion portion 20B) of an imaging member according to Modification Example 2 of the present disclosure. The photoelectric conversion portion 20B of the present modification example differs from the above embodiment in that the first layer 23A is formed over an entire surface and extends to overlie the readout electrode 21A.

[0117] For example, it is possible to manufacture the photoelectric conversion section 20A of the present modification example as follows.

[0118] As in the above embodiment, as in Fig. 14A, the insulating layer 22 is formed to cover the storage electrode 21B. Next, as shown in Fig. 14B illustrates, for example, after forming an opening 22H1 on the sense electrode 21A using dry etching, the insulating layer 22 is formed again to cover a side surface and a bottom surface of the opening 22H1. Then, as shown in Fig. 14C illustrates that after removing the insulating layer 22 on the sense electrode 21A by etching back, the second layer 23B is formed using, for example, ALD, as in Fig. 14D illustrates.

[0119] Next, as in Fig. 14E illustrates that after forming the protective film 29 for filling the opening 22H1, the protective film 29 formed on the second layer 23B is ground using a CMP method to expose the second layer 23B, as shown in Fig. 14F. Then, as in Fig. 14G illustrates that after re-forming the insulating layer 22, an opening 22H2 is formed in the readout electrode 21A, as shown in Fig. 14H. Next, as shown in Fig. 14I, the first layer 23A is formed on the insulating layer 22 to fill the opening 22H2, for example, using PVD. Then, the protective layer 24, the photoelectric conversion layer 25, and the upper electrode 26 are formed as in the above embodiment. Thus, the imaging element 10 shown in Fig. 13 is completed.

[0120] In this way, in the present modification example, a distance between the transfer electrode 21C and the semiconductor layer 23B is precisely controlled, etc., as compared with the above embodiment. Accordingly, in addition to the effects of the above embodiment, it is possible to widen a margin for voltage adjustment. (2-3. Modification Example 3)

[0121] Fig. 15 schematically illustrates a sectional configuration of a main portion (photoelectric conversion portion 20C) of an imaging member in Modification Example 3 of the present disclosure. As with Modification Example 2 above, in the photoelectric conversion portion 20C of the present modification example, the first layer 23A is formed over an entire surface and extends to overlie the readout electrode 21A.

[0122] For example, it is possible to manufacture the photoelectric conversion section 20A in the present modification example as follows.

[0123] As in the above embodiment, as shown in Fig. 16A illustrates that after forming the first layer 23A on the insulating layer 22, for example, using PVD, a hard mask 221 is formed on the first layer 23A. Next, as shown in Fig. 16B illustrates that after forming the opening 22H on the sense electrode 21A using, for example, dry etching, the insulating layer 22 is formed again to cover a side surface and a bottom surface of the opening 22H1, as shown in Fig. 16C. Then, as in Fig. 16D illustrates that after removing the insulating layer 22 on the sense electrode 21A by etching back, the second layer 23B is formed using ALD, for example, as shown in Fig. 16E illustrates.

[0124] Next, as in Fig. 16F illustrates that after forming the protective film 29 to fill the opening 22H, the protective film 29 formed on the second layer 23B is ground using the CMP method to expose the first layer 23A, as shown in Fig. 16G. Subsequently, as in Fig. 16H, the first layer 23A is formed again. Then, the protective layer 24, the photoelectric conversion layer 25, and the upper electrode 26 are formed as in the above embodiment. Thus, the imaging element 10 shown in Fig. 15 is completed.

[0125] In this way, in the method of manufacturing the present modification example, it is not necessary to include a process for forming an opening on the sense electrode 21A, thereby enabling a process more compatible with miniaturization.

[0126] Furthermore, the present technique is applicable to an imaging element having the following configuration. (2-4. Modification Example 4)

[0127] Fig. 17A schematically illustrates a sectional configuration of an imaging element 10A according to Modification Example 4 of the present disclosure.

[0128] Fig. Figure 17B schematically illustrates an example of a planar configuration of the imaging element 10A shown in Fig. 17A, and Fig. Figure 17A illustrates a section along a line II-II taken in Fig. 17B. For example, the imaging element 10A is a stacked-type imaging element in which the photoelectric conversion region 32 and the photoelectric conversion section 60 are stacked.

[0129] In the imaging element 10A of the present modification example, a color filter 55 that selectively transmits red light (R), green light (G), and blue light (B) is provided above the photoelectric conversion section 60 (on the light incident side S1) for each unit pixel P. Specifically, in a pixel unit 1a including four pixels arranged in two rows by two columns, two color filters that selectively transmit green light (G) are arranged on a diagonal line, and color filters that selectively transmit red light (R) and blue light (B) are each arranged one on a diagonal line orthogonal to the previous one. For example, in the unit pixels (Pr, Pg, and Pb), each including a color filter, light of each corresponding color is detected in the photoelectric conversion section 60. In other words, in the pixel section 1A, the pixels (Pr, Pg and Pb) which emit red light (R), green light (G) and blue light (B), respectively, are arranged.detect blue light (B), arranged in a Bayer layout.

[0130] For example, the photoelectric conversion section 60 includes a lower electrode 61 including a readout electrode 61A, a storage electrode 62B, a transfer electrode 61C, and a shielding electrode 61D, an insulating layer 62, a semiconductor layer 63 including a first layer 63A and a second layer 63B, a protective layer 64, a photoelectric conversion layer 65, and an upper electrode 66. Each of the lower electrode 61, the insulating layer 62, the semiconductor layer 63, the photoelectric conversion layer 65, and the upper electrode 66 has a configuration similar to that of the photoelectric conversion section 20 in the above embodiment. The photoelectric conversion region 32 detects light having a different wavelength range than the photoelectric conversion section 60.

[0131] In the imaging element 10A, of the light transmitted through the color filter 55, light of a visible light range (red light (R), green light (G), and blue light (B)) is absorbed by the photoelectric conversion section 60 in the unit pixel (Pr, Pg, and Pb) including each color filter, and other light, for example, light of an infrared light range (for example, light (infrared light (IR)) of 700 nm or more and 1000 nm or less), is transmitted through the photoelectric conversion section 60. The infrared light (IR) transmitted through the photoelectric conversion section 60 is detected in the photoelectric conversion area 32 in each unit pixel Pr, Pg, or Pb, and a signal charge corresponding to the infrared light (IR) is generated in each unit pixel Pr, Pg, or Pb.In other words, it becomes possible for the imaging device 1 including the imaging element 10A to simultaneously generate both a visible light image and an infrared light image.

[0132] It should be noted that the above embodiment illustrates, but is not limited to, an example in which the readout electrode 21A is provided for each unit pixel P. For example, as shown in Fig. 17B, ​​the readout electrode 21A may be formed one at a time in an approximate center of the pixel unit 1a, for example, assuming that the pixel unit 1a, which includes four unit pixels P arranged in two rows by two columns, is a repeating unit. (2-5. Modification Example 5)

[0133] Fig. 18A schematically illustrates a sectional configuration of an imaging element 10B according to Modification Example 5 of the present disclosure. Fig. Figure 18B schematically illustrates an example of a planar configuration of the imaging element 10B used in Fig. 18A, and Fig. Figure 18A illustrates a section along a line III-III taken in Fig. 18B. In the above modification example 7, the color filter 55, which selectively transmits red light (R), green light (G), and blue light (B), is provided over the photoelectric conversion section 60 (light incident side S1). However, as shown in, for example, Fig. 18A, the color filter 55 may be provided between the photoelectric conversion area 32 and the photoelectric conversion section 60.

[0134] For example, in the imaging element 10B, the color filter 55 has a configuration in which, within the pixel unit 1a, a color filter (color filter 55R) that selectively transmits at least red light (R) and a color filter (color filter 55B) that selectively transmits at least blue light (B) are arranged diagonally to each other. The photoelectric conversion section 60 (photoelectric conversion layer 65) is configured to selectively absorb, for example, a wavelength corresponding to green light, as in the above embodiment. This makes it possible to detect a signal corresponding to RGB in the photoelectric conversion regions (photoelectric conversion regions 32R and 32G) provided under a corresponding one of the photoelectric conversion section 60 and the color filters 55R and 55B, respectively.The imaging element 10B of the present modification example makes it possible to increase an area of ​​each RGB photoelectric conversion section compared with an imaging element having a general Bayer layout, thereby making it possible to improve an S / N ratio. (2-6. Modification Example 6)

[0135] Fig. 19 schematically illustrates a sectional configuration of an imaging element 10C according to Modification Example 6 of the present disclosure. In the imaging element 10C of the present modification example, two photoelectric conversion sections 20 and 80 and a photoelectric conversion region 32 are vertically stacked.

[0136] The photoelectric conversion sections 20 and 80 and the photoelectric conversion area 32 selectively detect light having a different wavelength range and perform photoelectric conversion. For example, the photoelectric conversion section 20 detects a green (G) signal. For example, the photoelectric conversion section 80 detects a blue (B) signal. For example, the photoelectric conversion area 32 detects a red (R) signal. This allows the imaging element 10C to detect a variety of color signal types in a single pixel without using a color filter.

[0137] For example, the photoelectric conversion section 80 is stacked over the photoelectric conversion section 20 and, like the photoelectric conversion section 20, has a configuration in which a lower electrode 81 and, for example, a semiconductor layer 83 including a first layer 83A and a second layer 83B, a protective layer 84, a photoelectric conversion layer 85, and an upper electrode 86 are stacked in this order from the first surface 30A side of the semiconductor substrate 30. As in the photoelectric conversion section 20, the lower electrode 81 includes a readout electrode 81A and a storage electrode 81B, which are electrically separated by an insulating layer 82. The insulating layer 82 has an opening 82H on the readout electrode 81A.An interlayer insulating layer 87 is provided between the photoelectric conversion section 80 and the photoelectric conversion section 20.

[0138] A through electrode 88 is coupled to the readout electrode 81A and penetrates the interlayer insulating film 87 and the photoelectric conversion section 20 to be electrically coupled to the readout electrode 21A in the photoelectric conversion section 20. Furthermore, the readout electrode 81A is electrically coupled to the floating diffusion FD provided on the semiconductor substrate 30 via the through electrodes 34 and 88, thereby making it possible to temporarily accumulate the carrier generated in the photoelectric conversion layer 85. Furthermore, the readout electrode 81A is electrically coupled to the amplifier transistor AMP or the like provided on the semiconductor substrate 30 via the through electrodes 34 and 88. <3. Application examples>(Application example 2)

[0139] Fig. Fig. 20 illustrates an example of an overall configuration of an imaging device (imaging device 1) including the imaging element (for example, the imaging element 10) shown in Fig. 1 is illustrated, etc.

[0140] For example, the imaging device 1 is a CMOS image sensor and receives the incident light (image light) from an object through an optical lens system (not shown), converts an amount of the incident light formed in an image on an imaging surface into an electrical signal on a pixel-by-pixel basis, and outputs the electrical signal as a pixel signal. The imaging device 1 includes a pixel portion 100A as an imaging surface on the semiconductor substrate 30, and also includes, for example, a vertical drive circuit 111, a column signal processing circuit 112, a horizontal drive circuit 113, an output circuit 114, a control circuit 115, and an input / output terminal 116 in a peripheral region of this pixel portion 100A.

[0141] For example, the pixel section 100A includes a plurality of unit pixels P arranged two-dimensionally in a matrix. In each of these unit pixels P, for example, one pixel drive line Lread (specifically, a row selection line and a reset control line) is provided per pixel row, and one vertical signal line Lsig is provided per pixel column. The pixel drive line Lread transmits a drive signal for reading a signal from a pixel. The pixel drive line Lread has one end coupled to an output terminal corresponding to each row of the vertical drive circuit 111.

[0142] The vertical drive circuit 111 is a pixel drive section that includes a shift register, an address decoder, or the like, and drives, for example, each unit pixel P of the pixel section 100A on a row-by-row basis. The signal output from each unit pixel P in a pixel row selected and scanned by the vertical drive circuit 111 is supplied to the column signal processing circuit 112 through each vertical signal line Lsig. The column signal processing circuit 112 includes an amplifier, a horizontal selection switch, or the like provided for each vertical signal line Lsig.

[0143] The horizontal drive circuit 113 includes a shift register, an address decoder, or the like, and sequentially drives each horizontal selection switch in the column signal processing circuit 112 during scanning. With this selective scanning by the horizontal drive circuit 113, each pixel signal to be transmitted through each vertical signal line Lsig is sequentially output to the horizontal signal line 121 and transmitted through the horizontal signal line 121 to an outside of the semiconductor substrate 30.

[0144] The output circuit 114 performs signal processing on the signal sequentially supplied from each column signal processing circuit 112 via the horizontal signal line 121 and outputs the signal. For example, the output circuit 114 performs buffering only in some cases, or performs black level adjustment, column variation compensation, and various digital signal processing, or the like, in other cases.

[0145] A circuit portion including the vertical drive circuit 111, the column signal processing circuit 112, the horizontal drive circuit 113, the horizontal signal line 121, and the output circuit 114 may be formed directly on the semiconductor substrate 30 or may be provided in an external control IC. Additionally, these circuit portions may also be formed on another substrate connected by a cable or the like.

[0146] The control circuit 115 receives a clock, data instructing an operation mode, or the like supplied from outside the semiconductor substrate 30, and also outputs data such as internal information of the imaging device 1. The control circuit 115 further includes a timer that generates various timing signals and performs drive control of an edge circuit such as the vertical drive circuit 111, the column signal processing circuit 112, and the horizontal drive circuit 113, or the like, based on the various timing signals generated by the timer.

[0147] The input / output port 116 exchanges signals with the external environment. (Application example 2)

[0148] In addition, for example, the imaging device 1 as described above is applicable to various electronic devices including an imaging system such as a digital still camera or a digital video camera, a mobile phone equipped with an imaging function, or other device equipped with an imaging function.

[0149] Fig. 21 is a block diagram illustrating an example of a configuration of an electronic device 1000.

[0150] As in Fig. 21, the electronic device 1000 includes an optical system 1001, the imaging device 1, and a DSP (Digital Signal Processor) 1002, and has a configuration in which the DSP 1002, a memory 1003, a display device 1004, a recording device 1005, an operating system 1006, and a power supply system 1007 are coupled via a bus 1008 to enable recording of a still image and a moving image.

[0151] The optical system 1001 includes one or a plurality of lenses and receives the incident light (image light) from an object to form an image on an imaging surface of the imaging device 1.

[0152] The imaging device 1 described above is applied to the imaging device 1. The imaging device 1 converts an amount of incident light formed in an image on the imaging surface by the optical system 1001 into an electrical signal on a pixel-by-pixel basis and supplies the electrical signal to the DSP 1002 as a pixel signal.

[0153] The DSP 1002 obtains an image by performing various signal processing on the signal from the imaging device 1 and causes the memory 1003 to temporarily hold the image data. The image data held by the memory 1003 is recorded in the recording device 1005 or supplied to the display device 1004 to display the image. In addition, the operating system 1006 accepts various operations performed by a user and supplies an operation signal to each block in the electronic device 1000, and the power supply system 1007 supplies an electric current necessary to drive each block in the electronic device 1000. (Application example 3)

[0154] Fig. 22A schematically illustrates an example of an overall configuration of a light detection system 2000 including the imaging device 1. Fig. 22B illustrates an example of a circuit configuration of the light detection system 2000. The light detection system 2000 includes a light emitting device 2001 as a light source section that emits infrared light L2, and a light detecting device 2002 as a light receiving section that includes a photoelectric conversion element. As the light detecting device 2002, it is possible to use the imaging device 1 described above. The light detection system 2000 may further include a system control section 2003, a light source driving section 2004, a sensor control section 2005, a light source-side optical system 2006, and a camera-side optical system 2007.

[0155] For the light detection device 2002, it is possible to detect light L1 and light L2. The light L1 is ambient light from outside, which is emitted by an object (measurement target) 2100 ( Fig. 22A). The light L2 is the light emitted by the light-emitting device 2001 and then reflected by the object 2100. For example, the light L1 is visible light, and the light L2 is infrared light, for example. The light L1 is detectable in the photoelectric conversion section in the light detection device 2002, and the light L2 is detectable in the photoelectric conversion area in the light detection device 2002. It is possible to obtain image information regarding the object 2100 from the light L1 and to obtain distance information between the object 2100 and the light detection system 2000 from the light L2. For example, the light detection system 2000 is mountable on an electronic device such as a smartphone or on a movable body such as a car.In the light-emitting device 2001, it is possible to include, for example, a semiconductor laser, a surface-emitting semiconductor laser, or a vertical cavity surface-emitting laser (VCSEL). For example, as a method for detecting the light L2 emitted from the light-emitting device 2001 by the light-detecting device 2002, it is possible to adopt an iTOF method, but is not limited thereto. For example, the iTOF allows the photoelectric conversion section to measure a distance to the object 2100 using the optical time of flight (TOF). For example, as the method for detecting the light L2 emitted from the light-emitting device 2001 by the light-detecting device 2002, it is also possible to adopt a structured light method or a stereo vision method.For example, the structured light method allows the distance between the light detection system 2000 and the object 2100 to be measured by projecting light with a predetermined pattern onto the object 2100 and analyzing the degree of distortion of the pattern. In addition, the stereo vision method, for example, allows the distance between the light detection system 2000 and the object 2100 to be measured by taking two or more images of the object 2100 using two or more cameras from two or more different angles. Note that it is possible to synchronously control the light emitting device 2001 and the light detecting device 2002 by the system control section 2003. <4. Practical Applications>(Practical application to an endoscopic surgery system)

[0156] A technique of the present disclosure (the present technique) is applicable to various products. For example, the technique of the present disclosure can be applied to a system for endoscopic surgery.

[0157] Fig. 23 is a view illustrating an example of a schematic configuration of an endoscopic surgery system to which the technology according to an embodiment of the present disclosure (the present technology) can be applied.

[0158] In Fig. 23 illustrates a state in which a surgeon (doctor) 11131 uses an endoscopic surgery system 11000 to perform surgery on a patient 11132 on a patient bed 11133. As shown, the endoscopic surgery system 11000 includes an endoscope 11100, other surgical instruments 11110 such as a pneumoperitoneum tube 11111 and an energy treatment device 11112, a support arm device 11120 supporting the endoscope 11100 thereon, and a trolley 11200 on which various endoscopic surgery devices are mounted.

[0159] The endoscope 11100 includes a lens tube 11101 having a region of a predetermined length from a distal end thereof for insertion into a body cavity of the patient 11132, and a camera head 11102 connected to a proximal end of the lens tube 11101. In the illustrated example, the endoscope 11100 is shown as including a rigid endoscope having the hard-type lens tube 11101. However, the endoscope 11100 may otherwise be included as a flexible endoscope having the flexible-type lens tube 11101.

[0160] The lens barrel 11101 has an opening at a distal end thereof, into which an objective lens is fitted. A light source device 11203 is connected to the endoscope 11100 such that light generated by the light source device 11203 is introduced into a distal end of the lens barrel 11101 through a light guide extending inside the lens barrel 11101 and radiated through the objective lens toward an observation target in a body cavity of the patient 11132. Note that the endoscope 11100 may be a straight-view endoscope, an oblique-view endoscope, or a side-view endoscope.

[0161] An optical system and an image pickup element are provided inside the camera head 11102 such that reflected light (observation light) from the observation target is converged onto the image pickup element by the optical system. The observation light is photoelectrically converted by the image pickup element to generate an electrical signal corresponding to the observation light, namely, an image signal corresponding to an observation image. The image signal is transmitted as raw data to a CCU 11201.

[0162] The CCU 11201 includes a central processing unit (CPU), a graphics processing unit (GPU), or the like, and integrally controls the operation of the endoscope 11100 and a display device 11202. Further, the CCU 11201 receives an image signal from the camera head 11102 and performs various image processes for displaying an image based on the image signal, such as a demosaic process.

[0163] The display device 11202 then displays an image based on an image signal for which the image processes have been performed by the CCU 11201, under the control of the CCU 11201.

[0164] The light source device 11203 includes a light source, such as a light-emitting diode (LED), and supplies irradiation light to the endoscope 11100 when imaging a surgical area.

[0165] An input device 11204 is an input interface for the endoscopic surgery system 11000. A user can input various types of information or instruction inputs to the endoscopic surgery system 11000 through the input device 11204. For example, the user would input an instruction or the like to change an image acquisition condition (type of irradiation light, magnification, focal length, or the like) by the endoscope 11100.

[0166] A treatment instrument control device 11205 controls a drive of the energy treatment device 11112 for cauterizing or cutting tissue, occluding a blood vessel, or the like. A pneumoperitoneum device 11206 introduces gas into a body cavity of the patient 11132 through the pneumoperitoneum tube 11111 to inflate the body cavity, secure the field of view of the endoscope 11100, and secure the working space for the surgeon. A recording device 11207 is a device capable of recording various types of information related to a surgical procedure. A printer 11208 is a device capable of printing various types of information related to a surgical procedure in various forms such as text, an image, or a graph.

[0167] It should be noted that the light source device 11203 that supplies irradiation light to the endoscope 11100 when imaging a surgical area may include a white light source, such as an LED, a laser light source, or a combination thereof. When a white light source includes a combination of red, green, and blue (RGB) laser light sources, since the output intensity and output timing can be controlled with a high degree of accuracy for each color (each wavelength), adjustment of the white balance of a captured image can be performed by the light source device 11203. Furthermore, in this case, when laser beams from the respective RGB laser light sources are irradiated at an observation target in a time-divided manner, driving of the image pickup elements of the camera head 11102 is controlled in synchronization with the irradiation timing.Then, images corresponding individually to the R, G, and B colors can also be captured in a time-division manner. According to this method, a color image can be obtained even if no color filters are provided for the image pickup element.

[0168] Furthermore, the light source device 11203 can be controlled such that the intensity of light to be output is changed every predetermined time. By controlling the driving of the image pickup element of the camera head 11102 in synchronization with the time of the change in the intensity of light to capture images in a time-division manner and synthesizing the images, a high dynamic range image free from underexposed blocked shadows and overexposed highlights can be generated.

[0169] Furthermore, the light source device 11203 may be configured to supply light of a predetermined wavelength band suitable for special light observation. In special light observation, for example, by utilizing the wavelength dependence of light absorption in a body tissue to emit light of a narrow band compared to irradiation light in ordinary observation (namely, white light), narrow-band observation (narrow-band imaging) is performed to image a predetermined tissue, such as a blood vessel, a surface area of ​​the mucous membrane, or the like, with high contrast. Alternatively, in special light observation, fluorescence observation may be performed to obtain an image from fluorescent light generated by irradiation with excitation light.In fluorescence observation, it is possible to perform observation of fluorescent light from a body tissue by irradiating excitation light onto the body tissue (autofluorescence observation), or to obtain a fluorescent light image by locally injecting a reagent, such as indocyanine green (ICG), into a body tissue and irradiating excitation light corresponding to a fluorescent light wavelength of the reagent onto the body tissue. The light source device 11203 can be configured to supply such narrow-band light and / or excitation light suitable for special light observation, as described above.

[0170] Fig. 24 is a block diagram showing an example of a functional configuration of the camera head 11102 and the Fig. 23 represents the CCU 11201.

[0171] The camera head 11102 includes a lens unit 11401, an image pickup unit 11402, a drive unit 11403, a communication unit 11404, and a camera head control unit 11405. The CCU 11201 includes a communication unit 11411, an image processing unit 11412, and a control unit 11413. The camera head 11102 and the CCU 11201 are connected to each other for communication by a transmission cable 11400.

[0172] The lens unit 11401 is an optical system provided at a junction with the lens barrel 11101. Observation light received by a distal end of the lens barrel 11101 is guided to the camera head 11102 and introduced into the lens unit 11401. The lens unit 11401 comprises a combination of a plurality of lenses including a zoom lens and a focusing lens.

[0173] The number of image pickup elements included in the image pickup unit 11402 may be one (single-plate type) or a plurality (multi-plate type). For example, when the image pickup unit 11402 is configured as the multi-plate type, image signals corresponding to respective R, G, and B are generated by the image pickup elements, and the image signals may be synthesized to obtain a color image. The image pickup unit 11402 may also be configured to include a pair of image pickup elements for acquiring respective image signals for the right eye and the left eye, ready for three-dimensional (3D) display. When 3D display is performed, the depth of a living body tissue in a surgical area can be more accurately understood by the surgeon 11131.Note that when the image pickup unit 11402 is configured as the stereoscopic type, a plurality of systems of lens units 11401 corresponding to the individual image pickup elements are provided.

[0174] Furthermore, the image pickup unit 11402 may not necessarily be provided on the camera head 11102. For example, the image pickup unit 11402 may be provided immediately behind the objective lens inside the lens barrel 11101.

[0175] The drive unit 11403 includes an actuator and moves the zoom lens and the focus lens of the lens unit 11401 by a predetermined distance along an optical axis under the control of the camera head control unit 11405. Consequently, the magnification and focal point of a captured image can be appropriately adjusted by the image pickup unit 11402.

[0176] The communication unit 11404 includes a communication device for transmitting and receiving various types of information to and from the CCU 11201. The communication unit 11404 transmits an image signal acquired by the image acquisition unit 11402 as raw data to the CCU 11201 via the transmission cable 11400.

[0177] In addition, the communication unit 11404 receives a control signal for controlling the driving of the camera head 11102 from the CCU 11201 and supplies the control signal to the camera head control unit 11405. The control signal includes information related to image capturing conditions, such as information that a frame rate of a captured image is designated, information that an exposure value in image capturing is designated, and / or information that a magnification and a focal point of a captured image are designated.

[0178] Note that image acquisition conditions such as frame rate, exposure value, magnification, or focal point can be specified by the user or automatically set by the control unit 11413 of the CCU 11201 based on a captured image signal. In the latter case, an automatic exposure (AE) function, an automatic focus (AF) function, and an automatic white balance (AWB) function are integrated into the endoscope 11100.

[0179] The camera head control unit 11405 controls the driving of the camera head 11102 based on a control signal from the CCU 11201 received by the communication unit 11404.

[0180] The communication unit 11411 includes a communication device for transmitting and receiving various types of information to and from the camera head 11102. The communication unit 11411 receives an image signal transmitted thereto from the camera head 11102 via the transmission cable 11400.

[0181] Furthermore, the communication unit 11411 transmits a control signal for controlling the driving of the camera head 11102 to the camera head 11102. The image signal and the control signal may be transmitted by electrical communication, optical communication, or the like.

[0182] The image processing unit 11412 performs various image processes on an image signal in the form of raw data transmitted thereto from the camera head 11102.

[0183] The control unit 11413 performs various types of control related to the image acquisition of a surgical area or the like by the endoscope 11100 and the display of an acquired image obtained by the image acquisition of the surgical area or the like. For example, the control unit 11413 generates a control signal for controlling the driving of the camera head 11102.

[0184] Further, based on an image signal for which image processing has been performed by the image processing unit 11412, the control unit 11413 controls the display device 11202 to display a captured image depicting the area of ​​a surgical operation or the like. Then, the control unit 11413 can recognize various objects in the captured image using various image recognition technologies. For example, the control unit 11413 can recognize a surgical instrument such as forceps, a specific area of ​​a living body, bleeding, haze when the energy treatment device 11112 is used, and so on by recognizing the shape, color, and so on of edges of objects included in a captured image.The control unit 11413 can cause various types of surgical support information to be displayed in an overlapping manner with an image of the surgical operation area when controlling the display device 11202 to display a captured image using a detection result. When surgical support information is displayed in an overlapping manner and presented to the surgeon 11131, the burden on the surgeon 11131 can be reduced, and the surgeon 11131 can continue the operation safely.

[0185] The transmission cable 11400 connecting the camera head 11102 and the CCU 11201 is an electrical signal cable suitable for communicating an electrical signal, an optical fiber suitable for optical communication, or a composite cable suitable for both electrical and optical communication.

[0186] Although in the illustrated example, communication is performed by wired communication using the transmission cable 11400, communication between the camera head 11102 and the CCU 11201 may be performed by wireless communication.

[0187] Some examples of an endoscopic surgery system to which the technique of the present disclosure is applicable have been described above. Of the configuration described above, the technique of the present disclosure is applicable to the image acquisition unit 11402. Applying the technique of the present disclosure improves detection accuracy by the image acquisition unit 11402.

[0188] It should be noted that the system for endoscopic surgery has been described herein as an example, but the technique of the present disclosure may be applied otherwise, for example, to a microsurgical system or the like. (Practical application to a mobile body)

[0189] The technique of the present disclosure is applicable to various products. For example, the technique of the present disclosure can be implemented as a device mounted on any type of moving body, such as a car, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, a personal mobility vehicle, an aircraft, a drone, a ship, a robot, a construction machine, or an agricultural machine (tractor).

[0190] Fig. 25 is a block diagram illustrating an example of a schematic configuration of a vehicle control system as an example of a moving body control system to which the technology according to an embodiment of the present disclosure can be applied.

[0191] The vehicle control system 12000 comprises a plurality of electronic control units that are interconnected via a communication network 12001. In the Fig. In the example shown in Fig. 25, the vehicle control system 12000 includes a drive system control unit 12010, a body system control unit 12020, an outside-vehicle information detection unit 12030, an inside-vehicle information detection unit 12040, and an integrated control unit 12050. In addition, a microcomputer 12051, a sound / image output section 12052, and an interface (I / F) of the vehicle-mounted network 12053 are shown as a functional configuration of the integrated control unit 12050.

[0192] The drive system control unit 12010 controls the operation of devices related to the drive system of the vehicle according to various types of programs. For example, the drive system control unit 12010 functions as a control device for a driving force generating device for generating the driving force of the vehicle, such as an internal combustion engine, a drive motor, or the like, a driving force transmission mechanism for transmitting the driving force to wheels, a steering mechanism for adjusting the steering angle of the vehicle, a braking device for generating the braking force of the vehicle, and the like.

[0193] The body system control unit 12020 controls the operation of various types of devices provided on a vehicle body according to various types of programs. For example, the body system control unit 12020 functions as a control device for a keyless entry system, a smart key system, a power window device, or various types of lights, such as a headlight, a backup light, a brake light, a turn signal, a fog light, or the like. In this case, radio waves transmitted from a mobile device as an alternative to a key or signals from various types of switches can be input to the body system control unit 12020. The body system control unit 12020 receives these input radio waves or signals and controls a door lock device, the power window device, the lights, or the like of the vehicle.

[0194] The vehicle-external information detection unit 12030 detects information about the external environment of the vehicle including the vehicle control system 12000. For example, the vehicle-external information detection unit 12030 is connected to an imaging section 12031. The vehicle-external information detection unit 12030 causes the imaging section 12031 to capture an image of the vehicle's external environment and receives the captured image. Based on the received image, the vehicle-external information detection unit 12030 can perform processing for detecting an object, such as a person, a vehicle, an obstacle, a sign, a sign on a road surface, or the like, or processing for detecting a distance thereto.

[0195] The imaging section 12031 is an optical sensor that receives light and outputs an electrical signal corresponding to the amount of light received. The imaging section 12031 can output the electrical signal as an image or can output the electrical signal as information about a measured distance. In addition, the light received by the imaging section 12031 can be visible light or can be invisible light, such as infrared rays or the like.

[0196] The vehicle interior information detection unit 12040 detects information about the vehicle interior. The vehicle interior information detection unit 12040 is connected, for example, to a driver condition detection section 12041 that detects the condition of a driver. The driver condition detection section 12041 includes, for example, a camera that records the driver. Based on detection information input from the driver condition detection section 12041, the vehicle interior information detection unit 12040 can calculate a driver's fatigue level or a driver's concentration level, or can determine whether the driver is dozing.

[0197] The microcomputer 12051 may calculate a control target value for the driving force generating device, the steering mechanism, or the braking device based on the information about the inside or outside of the vehicle obtained by the outside-vehicle information detecting unit 12030 or the inside-vehicle information detecting unit 12040, and output a control command to the drive system control unit 12010.For example, the microcomputer 12051 may perform cooperative control intended to implement functions of an advanced driver assistance system (ADAS), the functions including collision avoidance or impact mitigation for the vehicle, following distance-based following travel, constant speed travel, vehicle collision warning, vehicle lane departure warning, or the like.

[0198] In addition, the microcomputer 12051 can perform cooperative control intended for automated driving, which causes the vehicle to drive automatically without depending on the driver's operation or the like, by controlling the driving force generating device, the steering mechanism, the braking device, or the like based on the information about the outside or the inside of the vehicle, the information obtained by the outside-vehicle information detecting unit 12030 or the inside-vehicle information detecting unit 12040.

[0199] In addition, the microcomputer 12051 may output a control command to the body system control unit 12020 based on the information about the exterior of the vehicle obtained by the external vehicle information detection unit 12030. For example, the microcomputer 12051 may perform cooperative control intended to prevent glare by controlling the headlight to switch from a high beam to a low beam, for example, according to the position of a preceding vehicle or an oncoming vehicle detected by the external vehicle information detection unit 12030.

[0200] The sound / image output section 12052 transmits an output signal of at least one of a sound and an image to an output device capable of visually or audibly communicating information to an occupant of the vehicle or the exterior of the vehicle. In the example of Fig. 25, a speaker 12061, a display section 12062, and an instrument panel 12063 are illustrated as the output device. The display section 12062 may include, for example, at least one of an in-vehicle display and a head-up display.

[0201] Fig. 26 is a diagram showing an example of the mounting position of the imaging section 12031.

[0202] In Fig. 26, the imaging section 12031 includes imaging sections 12101, 12102, 12103, 12104 and 12105.

[0203] The imaging sections 12101, 12102, 12103, 12104, and 12105 are arranged, for example, at positions on a front end, side mirrors, a rear bumper, and a rear door of the vehicle 12100, and a position on an upper portion of a windshield within the vehicle interior. The imaging section 12101 provided at the front end and the imaging section 12105 provided at the upper portion of the windshield within the vehicle interior mainly obtain an image from in front of the vehicle 12100. The imaging sections 12102 and 12103 provided at the side mirrors mainly obtain an image from the sides of the vehicle 12100. The imaging section 12104 provided at the rear bumper or the rear door mainly obtains an image from behind the vehicle 12100.The imaging section 12105 provided at the upper portion of the windshield within the vehicle interior is mainly used to detect a preceding vehicle, a pedestrian, an obstacle, a signal, a traffic sign, a lane, or the like.

[0204] Furthermore, Fig.26 illustrates an example of the photographing ranges of the imaging sections 12101 to 12104. An imaging area 12111 represents the imaging range of the imaging section 12101 provided at the front end. The imaging areas 12112 and 12113 respectively represent the imaging ranges of the imaging sections 12102 and 12103 provided at the side mirrors. An imaging area 12114 represents the imaging range of the imaging section 12104 provided at the rear bumper or the tailgate. A bird's-eye view of the vehicle 12100 when viewed from above is obtained, for example, by superimposing image data imaged by the imaging sections 12101 to 12104.

[0205] At least one of the imaging sections 12101 to 12104 may have a function of obtaining distance information. For example, at least one of the imaging sections 12101 to 12104 may be a stereo camera consisting of a plurality of imaging elements, or may be an imaging element having pixels for phase difference detection.

[0206] For example, the microcomputer 12051 may determine a distance to each three-dimensional object within the imaging areas 12111 to 12114 and a temporal change of the distance (relative speed with respect to the vehicle 12100) on the basis of the distance information obtained from the imaging sections 12101 to 12104, and thereby extract, in particular, as a preceding vehicle, a nearest three-dimensional object that is located on a travel path of the vehicle 12100 and that travels at a predetermined speed (e.g., equal to 0 km / h or higher) in substantially the same direction as the vehicle 12100.Furthermore, the microcomputer 12051 can predetermine a following distance to be maintained from a preceding vehicle and perform automatic braking control (including follow-up stop control), automatic acceleration control (including follow-up start control), or the like. Consequently, it is possible to perform cooperative control intended for automatic driving, which allows the vehicle to drive autonomously without depending on the driver's intervention or the like.

[0207] For example, the microcomputer 12051 can classify three-dimensional object data about three-dimensional objects into three-dimensional object data of a two-wheeled vehicle, a standard-size vehicle, a large-size vehicle, a pedestrian, a telephone pole, and other three-dimensional objects based on the distance information obtained from the imaging sections 12101 to 12104, extract the classified three-dimensional object data, and use the extracted three-dimensional object data to automatically avoid an obstacle. For example, the microcomputer 12051 identifies obstacles around the vehicle 12100 as obstacles that the driver of the vehicle 12100 can visually recognize and obstacles that are difficult for the driver of the vehicle 12100 to visually recognize. Then, the microcomputer 12051 determines a collision risk that indicates a risk of collision with each obstacle.In a situation where the collision risk is equal to or higher than a set value and thus there is a possibility of a collision, the microcomputer 12051 issues a warning to the driver through the speaker 12061 or the display section 12062 and performs forced deceleration or avoidance steering through the drive system control unit 12010. The microcomputer 12051 can thereby assist driving to avoid a collision.

[0208] At least one of the imaging sections 12101 to 12104 may be an infrared camera that detects infrared rays. For example, the microcomputer 12051 may detect a pedestrian by determining whether or not there is a pedestrian in captured images of the imaging sections 12101 to 12104. Such detection of a pedestrian is performed, for example, by a process of extracting characteristic points in the captured images of the imaging sections 12101 to 12104 as infrared cameras and a process of determining whether or not it is the pedestrian by performing pattern matching processing on a series of characteristic points representing the contour of the object.When the microcomputer 12051 determines that there is a pedestrian in the imaged images of the imaging sections 12101 to 12104, thus detecting the pedestrian, the audio / video output section 12052 controls the display section 12062 to display a square contour line for highlighting, superimposed on the detected pedestrian. The audio / video output section 12052 can also control the display section 12062 to display an icon or the like representing the pedestrian at a desired position.

[0209] Although some embodiments and modification examples 1-6, application examples, and practical applications have been described above, the content of the present disclosure is not limited to the above embodiment, etc., but various modifications are possible. For example, in the above embodiment, the photoelectric conversion section 20 that detects green light and the photoelectric conversion regions 32B and 32R that detect blue light and red light, respectively, are configured as an imaging element by stacking, but the content of the present disclosure is not limited to such a configuration. For example, the red or blue light may be detected in the photoelectric conversion section, or the green light may be detected in the photoelectric conversion region.

[0210] In addition, the number of these photoelectric conversion sections and photoelectric conversion areas and their ratios are not limited, and two or more photoelectric conversion sections may be provided, or a plurality of color signals may be detected by only the photoelectric conversion section.

[0211] Furthermore, in the above embodiment, etc., as a plurality of electrodes included in the lower electrode 21, an example of a configuration in which two electrodes including a readout electrode 21A and a storage electrode 21B are provided, or in which three electrodes including the readout electrode 21A, the storage electrode 21B, and the transfer electrode 21C, or the readout electrode 21A, the storage electrode 21B, and the shield electrode 21D are provided, has been described. Other than this, four or more electrodes such as a discharge electrode or the like may be provided.

[0212] It should be noted that the effects described herein are merely examples and are not limiting, and other effects may exist.

[0213] It should be noted that it is possible for the present technique to have a configuration as follows. According to the present technique, in the following configuration, there is provided a semiconductor layer comprising a first layer and a second layer, wherein between an insulating layer covering the first electrode of a first electrode and a second electrode and having an opening above the second electrode, and a photoelectric conversion layer, the first layer is formed at least over the first electrode, and the second layer is formed at least over the second electrode while being electrically coupled to the second electrode via the opening and having a difference from the first layer in at least one of material composition, crystallinity, contained impurity concentration, or constituent element.This improves a charge carrier transport property to the second electrode, making it possible to improve a recorded image quality. (1) Imaging element comprising: a first electrode and a second electrode; a third electrode disposed opposite the first electrode and the second electrode; a photoelectric conversion layer provided between the first electrode and the third electrode and between the second electrode and the third electrode; an insulating layer provided between the first electrode and the photoelectric conversion layer and between the second electrode and the photoelectric conversion layer, the insulating layer having an opening above the second electrode; and a semiconductor layer comprising a first layer and a second layer, wherein the first layer is provided between the photoelectric conversion layer and the insulating layer and is formed at least over the first electrode, and the second layer is formed at least over the second electrode while being electrically coupled to the second electrode via the opening and differs from the first layer in at least one of material composition, crystallinity, contained impurity concentration, or constituent element. (2) Imaging element according to (1), wherein an energy level at a lowest end of a conduction band of the second layer is equal to an energy level at a lowest end of a conduction band of the first layer or is lower than the energy level at the lowest end of the conduction band of the first layer. (3) The imaging member according to (1) or (2), further comprising a first protective layer, wherein the first protective layer comprises an inorganic material between the photoelectric conversion layer and the semiconductor layer. (4) Imaging element according to (3), wherein an energy level at a lowest end of a conduction band of the first layer is equal to an energy level at a lowest end of a conduction band of the first protective layer or lower than the energy level at the lowest end of the conduction band of the first protective layer, and an energy level at the lowest end of the conduction band of the first protective layer is equal to or lower than an energy level at a lowest end of a conduction band of the photoelectric conversion layer. (5) Imaging element according to (3) or (4), wherein the second layer further comprises a second protective layer, the second protective layer being provided along the opening and having an insulating property between the second layer and the first protective layer; and an energy level at a lowest end of a conduction band of the second layer is shallower than an energy level at a lowest end of a conduction band of the second protective layer, the energy level at the lowest end of the conduction band of the second protective layer is shallower than a LUMO of the photoelectric conversion layer, and the LUMO of the photoelectric conversion layer is shallower than an energy level at a lowest end of a conduction band of the first protective layer. (6) An imaging element according to any one of (1) to (5), wherein the first layer is a crystalline layer and the second layer is an amorphous layer. (7) An imaging element according to any one of (1) to (6), wherein the first layer has an impurity concentration that is lower than the impurity concentration of the second layer. (8) An imaging element according to any one of (1) to (7), wherein the first layer has an impurity concentration of one-tenth or less of the impurity concentration of the second layer. (9) An imaging element according to any one of (1) to (8), wherein an impurity contained in the first layer and the second layer is carbon. (10) An imaging element according to any one of (1) to (9), wherein the semiconductor layer contains at least one type of element selected from indium, gallium, silicon, zinc, aluminum and tin. (11) An imaging element according to any one of (1) to (10), wherein the semiconductor layer comprises IGZO, Ga2O3, GZO, IZO, ITO, InGaAlO or InGaSiO. (12) An imaging element according to any one of (3) to (11), wherein the first protective layer comprises at least one type of element selected from tantalum, titanium, vanadium, niobium, tungsten, zirconium, hafnium, scandium, yttrium, lanthanum, gallium and magnesium. (13) An imaging element according to any one of (1) to (12), wherein the first electrode and the second electrode are arranged on an opposite side of a light incident surface with respect to the photoelectric conversion layer. (14) An imaging element according to any one of (1) to (13), wherein a voltage is applied separately to each of the first electrode and the second electrode. (15) The imaging element according to any one of (1) to (14), further comprising a fourth electrode between the first electrode and the second electrode. (16) Imaging element according to (14) or (15), wherein one or a plurality of photoelectric conversion sections and one or a plurality of photoelectric conversion regions are stacked, wherein the one or a plurality of photoelectric conversion sections comprise the first electrode, the second electrode, the third electrode, the photoelectric conversion layer, and the semiconductor layer, and wherein the one or a plurality of photoelectric conversion regions perform photoelectric conversion on light having a different wavelength range than the photoelectric conversion section. (17) Imaging element according to (16), wherein the one or more photoelectric conversion regions are embedded in a semiconductor substrate, and the one or more photoelectric conversion sections are formed on a first surface side of the semiconductor substrate. (18) A method of manufacturing an imaging element, the imaging element comprising: a first electrode and a second electrode, a third electrode arranged opposite the first electrode and the second electrode, a photoelectric conversion layer provided between the first electrode and the third electrode and between the second electrode and the third electrode, an insulating layer provided between the first electrode and the photoelectric conversion layer and between the second electrode and the photoelectric conversion layer, the insulating layer having an opening above the second electrode, and a semiconductor layer comprising a first layer and a second layer, wherein the first layer is provided between the photoelectric conversion layer and the insulating layer and is formed at least over the first electrode, and the second layer is formed at least over the second electrode while being electrically coupled to the second electrode via the opening and differing from the first layer in at least one of material composition, crystallinity, contained impurity concentration, or constituent element, the method comprising: forming the first layer using a physical vapor deposition process; and Forming the second layer using an atomic layer deposition process. (19) A light detection device comprising a plurality of pixels each comprising one or a plurality of imaging elements, wherein the one or a plurality of imaging elements comprises: a first electrode and a second electrode; a third electrode disposed opposite the first electrode and the second electrode; a photoelectric conversion layer provided between the first electrode and the third electrode and between the second electrode and the third electrode; an insulating layer provided between the first electrode and the photoelectric conversion layer and between the second electrode and the photoelectric conversion layer, the insulating layer having an opening above the second electrode; and a semiconductor layer comprising a first layer and a second layer, wherein the first layer is provided between the photoelectric conversion layer and the insulating layer and is formed at least over the first electrode, and the second layer is formed at least over the second electrode while being electrically coupled to the second electrode via the opening and differs from the first layer in at least one of material composition, crystallinity, contained impurity concentration, or constituent element.

[0214] This application claims the benefit of Japanese priority patent application JP2022-050525, filed with the Japan Patent Office on March 25, 2022, the entire contents of which are incorporated herein by reference.

[0215] Those skilled in the art should understand that various modifications, combinations, sub-combinations and changes may occur depending on design requirements and other factors, provided they are within the scope of the appended claims or their equivalents. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2020 / 203249

[0003] JP 2022-050525

[0214]

Claims

[1] Imaging element comprising: a first electrode and a second electrode; a third electrode disposed opposite the first electrode and the second electrode; a photoelectric conversion layer provided between the first electrode and the third electrode and between the second electrode and the third electrode; an insulating layer provided between the first electrode and the photoelectric conversion layer and between the second electrode and the photoelectric conversion layer, the insulating layer having an opening above the second electrode; and a semiconductor layer comprising a first layer and a second layer, wherein the first layer is provided between the photoelectric conversion layer and the insulating layer and is formed at least over the first electrode, and the second layer is formed at least over the second electrode while being electrically coupled to the second electrode via the opening and differs from the first layer in at least one of material composition, crystallinity, contained impurity concentration, or constituent element. [2] The imaging member of claim 1, wherein an energy level at a lowest end of a conduction band of the second layer is equal to or lower than an energy level at a lowest end of a conduction band of the first layer. [3] The imaging member of claim 1, further comprising a first protective layer, wherein the first protective layer comprises an inorganic material between the photoelectric conversion layer and the semiconductor layer. [4] An imaging element according to claim 3, wherein an energy level at a lowest end of a conduction band of the first layer is equal to an energy level at a lowest end of a conduction band of the first protective layer or lower than the energy level at the lowest end of the conduction band of the first protective layer, and an energy level at the lowest end of the conduction band of the first protective layer is equal to or lower than an energy level at a lowest end of a conduction band of the photoelectric conversion layer. [5] An imaging element according to claim 3, wherein the second layer further comprises a second protective layer, the second protective layer being provided along the opening and having an insulating property between the second layer and the first protective layer; and an energy level at a lowest end of a conduction band of the second layer is shallower than an energy level at a lowest end of a conduction band of the second protective layer, the energy level at the lowest end of the conduction band of the second protective layer is shallower than a LUMO of the photoelectric conversion layer, and the LUMO of the photoelectric conversion layer is shallower than an energy level at a lowest end of a conduction band of the first protective layer. [6] The imaging member of claim 1, wherein the first layer comprises a crystalline layer and the second layer comprises an amorphous layer. [7] The imaging member of claim 1, wherein the first layer has an impurity concentration lower than the impurity concentration of the second layer. [8] The imaging member of claim 1, wherein the first layer has an impurity concentration of one-tenth or less of the impurity concentration of the second layer. [9] The imaging member of claim 1, wherein an impurity contained in the first layer and the second layer comprises carbon. [10] The imaging member according to claim 1, wherein the semiconductor layer contains at least one kind of element selected from indium, gallium, silicon, zinc, aluminum and tin. [11] The imaging member of claim 1, wherein the semiconductor layer comprises IGZO, Ga2O3, GZO, IZO, ITO, InGaAlO or InGaSiO. [12] The imaging member of claim 3, wherein the first protective layer comprises at least one kind of element selected from tantalum, titanium, vanadium, niobium, tungsten, zirconium, hafnium, scandium, yttrium, lanthanum, gallium and magnesium. [13] The imaging member according to claim 1, wherein the first electrode and the second electrode are arranged on an opposite side of a light incident surface with respect to the photoelectric conversion layer. [14] The imaging member of claim 1, wherein a voltage is applied separately to each of the first electrode and the second electrode. [15] The imaging member of claim 1, further comprising a fourth electrode between the first electrode and the second electrode. [16] The imaging member according to claim 14, wherein one or a plurality of photoelectric conversion sections and one or a plurality of photoelectric conversion regions are stacked, wherein the one or a plurality of photoelectric conversion sections comprise the first electrode, the second electrode, the third electrode, the photoelectric conversion layer, and the semiconductor layer, and wherein the one or a plurality of photoelectric conversion regions perform photoelectric conversion on light having a different wavelength range than the photoelectric conversion section. [17] An imaging element according to claim 16, wherein the one or more photoelectric conversion regions are embedded in a semiconductor substrate, and the one or more photoelectric conversion sections are formed on a first surface side of the semiconductor substrate. [18] A method of manufacturing an imaging element, the imaging element comprising: a first electrode and a second electrode, a third electrode arranged opposite the first electrode and the second electrode, a photoelectric conversion layer provided between the first electrode and the third electrode and between the second electrode and the third electrode, an insulating layer provided between the first electrode and the photoelectric conversion layer and between the second electrode and the photoelectric conversion layer, the insulating layer having an opening above the second electrode, and a semiconductor layer comprising a first layer and a second layer, wherein the first layer is provided between the photoelectric conversion layer and the insulating layer and is formed at least over the first electrode, and the second layer is formed at least over the second electrode while being electrically coupled to the second electrode via the opening and differing from the first layer in at least one of material composition, crystallinity, contained impurity concentration, or constituent element, the method comprising: forming the first layer using a physical vapor deposition process; and Forming the second layer using an atomic layer deposition process. [19] A light detection device comprising a plurality of pixels each comprising one or a plurality of imaging elements, the one or a plurality of imaging elements comprising: a first electrode and a second electrode; a third electrode disposed opposite the first electrode and the second electrode; a photoelectric conversion layer provided between the first electrode and the third electrode and between the second electrode and the third electrode; an insulating layer provided between the first electrode and the photoelectric conversion layer and between the second electrode and the photoelectric conversion layer, the insulating layer having an opening above the second electrode; and a semiconductor layer comprising a first layer and a second layer, wherein the first layer is provided between the photoelectric conversion layer and the insulating layer and is formed at least over the first electrode, and the second layer is formed at least over the second electrode while being electrically coupled to the second electrode via the opening and differs from the first layer in at least one of material composition, crystallinity, contained impurity concentration, or constituent element.

Images