Optoelectronic device including an active organic layer with improved performance and a method for manufacturing said device

Abstract

The present invention relates to a method for manufacturing an optoelectronic device (35), comprising the steps of: forming first and second electrically conductive pads (44, 45) on a support; depositing an active organic layer covering the first and second electrically conductive pads; depositing a first interface layer on the active organic layer in contact with the active organic layer; forming a first opening in the first interface layer and forming a second opening in the active organic layer in alignment with the first opening to expose a second electrically conductive pad; and forming a second interface layer (62) extending at least partially from the first and second openings, wherein the second interface layer contacts the first interface layer and the second electrically conductive pad.

Description

Technology Field

[0001] This patent application claims priority to French patent application FR19 / 08250, the contents of which are incorporated herein by reference. Background Technology

[0002] The present invention generally relates to an optoelectronic device comprising a light sensor having an organic photodiode or a display pixel having an organic light-emitting diode, and a method for manufacturing the same.

[0003] The manufacture of an optoelectronic device generally involves the continuous formation of elements that overlap at least partially, at least one of which is made of an organic material. A method for manufacturing an organic element includes the steps of depositing an organic layer and etching a portion of the organic layer to define the boundaries of the organic element.

[0004] Organic optoelectronic devices generally include an active organic layer, which is a region of the optoelectronic device where most of the radiation of interest is captured by the optoelectronic device or most of the radiation of interest is emitted by the optoelectronic device.

[0005] A disadvantage is that the steps of the optoelectronic device manufacturing method, particularly the active layer etching step, can cause degradation of the active layer and reduce the performance of the optoelectronic device. The problem to be solved

[0006] One embodiment overcomes all or part of the disadvantages of the previously described optoelectronic device.

[0007] The objective of one embodiment is to prevent the degradation of the active layer during the manufacture of an optoelectronic device.

[0008] The objective of one embodiment is to provide a method for manufacturing an optoelectronic device having improved performance. means of solving the problem

[0009] One embodiment provides a method for manufacturing an optoelectronic device comprising the following successive steps:

[0010] a) a step of forming first and second electrically conductive pads on a support;

[0011] b) a step of depositing an active organic layer covering the first and second electrically conductive pads;

[0012] c) a step of depositing a first interface layer on the active organic layer in contact with the active organic layer;

[0013] d) a step of forming a first opening in the first interface layer and forming a second opening in the active organic layer in alignment with the first opening to expose the second electrically conductive pad;

[0014] e) forming a second interface layer extending at least partially from the first and second openings, wherein the second interface layer contacts the first interface layer and the second electrically conductive pad.

[0015] According to one embodiment, the formation of the first opening and / or the second opening is achieved by reactive ion etching.

[0016] According to one embodiment, step d) includes applying a mask to a first interface layer, wherein the mask includes a third opening, and the first opening is etched in alignment with the third opening.

[0017] According to one embodiment, step d) includes the step of depositing a resist layer on a first interface layer and the step of forming a third opening in the resist layer, wherein the first opening is etched in alignment with the third opening.

[0018] According to one embodiment, the method comprises, between steps a) and b), a step of forming a resist block facing a second electrically conductive pad, wherein the block comprises a top and a side, and after step c), a stack comprising an active organic layer and a first interface layer particularly covers the top of the block and does not completely cover the side, and the method comprises, in step d), a step of removing the block.

[0019] One embodiment also provides a photoelectronic device comprising the following:

[0020] - Support and;

[0021] - First and second electrically conductive pads on the support;

[0022] - An active organic layer covering the first and second electrically conductive pads;

[0023] - A first interface layer that contacts and covers the active organic layer;

[0024] - A first opening of the first interface layer and a second opening of the active organic layer aligned with the first opening;

[0025] - A second interface layer extending at least partially from the first and second openings, wherein the second interface layer is in contact with the first interface layer and the second electrically conductive pad.

[0026] According to one embodiment, the first interface layer and / or the second interface layer comprises at least one compound selected from the group comprising the following components:

[0027] - Metal oxides and;

[0028] - Host / molecular dopant systems;

[0029] - Conductive or doped semiconductor polymers and;

[0030] - Carbonates and;

[0031] - Polymer electrolytes and;

[0032] - A mixture of two or more of these substances.

[0033] According to one embodiment, the first interface layer and the second interface layer are made of different materials.

[0034] According to one embodiment, the first and second conductive pads comprise at least one compound selected from the group comprising the following components:

[0035] - Conductive oxide and;

[0036] - Metal or metal alloy and;

[0037] - Conductive polymer and;

[0038] - Carbon, silver and / or copper nanowires;

[0039] - Graphene and;

[0040] - A mixture of at least two of these substances.

[0041] According to one embodiment, the active organic layer comprises a P-type semiconductor polymer and an N-type semiconductor material, and the P-type semiconductor polymer is poly(3-hexylthiophene) (P3HT), poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4,7-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT), poly[(4,8-bis-(2-ethylhexyloxy)-benzo[1,2-b;4,5-b']dithiophene)-2,6-diyl-alt-(4-(2-ethylhexanoyl)-thieno[3,4-b]thiophene))-2,6-diyl] (PBDTTT-C), poly[2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene-vinylene] (MEH-PPV), or The material is poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)-alt-4,7(2,1,3-benzothiadiazole)](PCPDTBT); and the N-type semiconductor material is fullerene, [6,6]-phenyl-C61-methylbutanoate (

[60] PCBM), [6,6]-phenyl-C71-methylbutanoate (

[70] PCBM), perylene diimide, zinc oxide, or a nanocrystal capable of forming quantum dots.

[0042] According to one embodiment, the device can emit or capture electromagnetic radiation, and the active organic layer is a layer of the optoelectronic device in which most of the electromagnetic radiation is captured by the optoelectronic device or most of the electromagnetic radiation is emitted by the optoelectronic device. Brief explanation of the drawing

[0043] In addition to the features and advantages described above, others will be described in detail in the following description of specific embodiments provided as examples rather than limitations, with reference to the accompanying drawings. Figure 1 is a simplified partial cross-sectional view of a structure obtained in one step of an example of a method for manufacturing an optoelectronic device including an active organic layer. Figure 2 illustrates another step of the above method. Figure 3 illustrates another step of the above method. Figure 4 illustrates another step of the above method. FIG. 5 illustrates an image obtained by an optoelectronic device illustrating a first defect in the active layer of the optoelectronic device. FIG. 6 illustrates an image obtained by an optoelectronic device illustrating a second defect in the active layer of the optoelectronic device. FIG. 7 is a simplified partial cross-sectional view of a structure obtained in the step of an embodiment of a method for manufacturing an optoelectronic device including an active organic layer. Figure 8 illustrates another step of the above method. Figure 9 illustrates another step of the above method. Figure 10 illustrates another step of the above method. Figure 11 illustrates another step of the above method. FIG. 12 is a simplified partial cross-sectional view of a structure obtained in a step of another embodiment of a method for manufacturing an optoelectronic device including an active organic layer. Figure 13 illustrates another step of the above method. Figure 14 illustrates another step of the above method. FIG. 15 illustrates another step of the above method. FIG. 16 illustrates another step of the above method. FIG. 17 is a simplified partial plan view of an embodiment of an organic photodiode. FIG. 18 is a simplified partial cross-sectional view of a structure obtained in a step of another embodiment of a method for manufacturing an optoelectronic device including an active organic layer. FIG. 19 illustrates another step of the above method. FIG. 20 illustrates another step of the above method. FIG. 21 illustrates another step of the above method. FIG. 22 illustrates another step of the above method. FIG. 23 illustrates another step of the above method. FIG. 24 illustrates another step of the above method. Specific details for implementing the invention

[0044] Similar features in various drawings are designated by similar reference numbers. In particular, structural and / or functional features common across various embodiments may have the same reference number and may have the same structural, dimensional, and material properties. For clarity, only steps and elements useful for understanding the embodiments described herein have been illustrated and described in detail. In particular, circuits for controlling photodiodes and light-emitting diodes are well known to those skilled in the art and are therefore not described in detail.

[0045] Additionally, in this specification, the terms "insulating" and "conductive" are considered to mean "electrically insulating" and "electrically conductive," respectively. Also, unless otherwise specified, "contacting" means "mechanically contacting." Additionally, the term "radiation of interest" refers to radiation that is desired to be captured or emitted by the optoelectronic device. For example, the radiation of interest may include wavelengths in the visible spectrum and near-infrared, namely, wavelengths in the range of 400 nm to 1,700 nm for the visible spectrum, more specifically 400 nm to 700 nm, and wavelengths in the range of 700 nm to 1,700 nm for the near-infrared spectrum. The transmittance of a layer to radiation corresponds to the ratio of the intensity of radiation entering the layer to the intensity of radiation emanating from the layer, and the beam of incident radiation is perpendicular to the layer. In the following description, if the transmittance of radiation through a layer or film is less than 10%, the layer or film is said to be opaque to radiation. In the following description, when the transmittance of radiation through a layer or film is greater than 10%, the layer or film is said to be transparent to radiation.

[0046] In the following description, when there is a reference to terms defining absolute positions such as "forward," "rear," "top," "bottom," "left," "right," etc., or relative terms such as "top," "bottom," "upward," "downward," etc., or directional terms such as "horizontal," "vertical," etc., this indicates the optoelectronic device in the orientation of the drawing or in its normal position of use. Unless otherwise specified, expressions such as "nearly," "about," "substantially," and "to some extent" mean within 10%, preferably within 5%.

[0047] FIGS. 1 to 4 are simplified partial cross-sectional views of a structure obtained in a continuous step of a method for manufacturing an optoelectronic device (5) including a photoelectronic sensor.

[0048] Figure 1 shows the structure obtained after the following step:

[0049] - A step of providing a support (10) including an upper surface (12);

[0050] - A step of forming first and second conductive pads (14, 15) on the surface (12) of the support (10);

[0051] - A step of forming an interface layer (16) on each conductive pad (14, 15);

[0052] - A step of depositing an active organic layer (18) over the entire surface (12) and, in particular, covering the interface layer (16).

[0053] FIG. 2 illustrates a structure obtained after forming an etching mask (20) on an active layer (18). In one example, the etching mask (20) is a rigid mechanical part applied to the active layer (18). In another example, the etching mask (20) is obtained by forming an opening (24) in the photosensitive layer (22) by photolithography techniques that deposit a photosensitive resist layer (22) on the active layer (18) and expose the organic layer (18) at the level of the second pad (15). In another example, the etching mask (20) is obtained by directly depositing a resin block at a desired location on the active layer (18) by, for example, inkjet, heliography, silk screening, flexography, or nanoimprint. In this case, there is no photolithography step.

[0054] FIG. 3 illustrates a structure obtained after etching the opening (26) of the active layer (18) and then removing the etching mask (20). The opening (26) is positioned to coincide with the opening (24) and exposes the second pad (15). As shown in FIG. 3, the opening (26) defines two active regions (28), each associated with a photoelectronic component, and each active region (28) covers one of the first pads (14).

[0055] FIG. 4 illustrates a structure obtained after the formation of an interface layer (30) covering an active region (28) and a second pad (15) for each optoelectronic component. Thus, two optoelectronic components (PH) are obtained. According to one example, a film of material forming the interface layer (30) may be deposited over the entire structure shown in FIG. 3, and the boundary of the interface layer (30) may be obtained by etching by performing an etching mask that can be formed by a photolithography step on a resist layer deposited over the entire film, or by depositing a resin block directly at a desired location on the film by, for example, inkjet printing, heliography, silk screening, flexography, or nanoimprinting. According to another example, the interface layer (30) may be deposited directly at a desired location by, for example, inkjet printing, heliography, silk screening, flexography, or nanoimprinting.

[0056] The performance of the active layer (28) of each optoelectronic component (PH) depends particularly on the surface condition of the active layer (28) in contact with the interface layer (30). Generally, it is desirable for the surface of the active layer (28) in contact with the interface layer (30) to have as few defects as possible, where defects may correspond to surface irregularities, particularly scratches, or unwanted deposition (particles, contamination, etc.) inserted between the active region (28) and the interface layer (30). A disadvantage is that the steps of the aforementioned manufacturing method may result in an active region (28) exhibiting defects.

[0057] If the etching mask (20) is a rigid mechanical part applied to the active layer (18) during the formation step of the opening (26), contact between the etching mask (20) and the active layer (18), particularly during the placement of the etching mask (20), can form surface defects on the active layer (18). These defects may correspond to scratches that can spread over the entire thickness of the active layer (18). Such defects result in localized degradation of the performance of the active layer (18), for example, at higher leakage current or lower sensitivity.

[0058] FIG. 5 illustrates an image obtained when the optoelectronic device (5) corresponds to an image sensor used for fingerprint acquisition and the etching mask (20) is a rigid mechanical part applied to the active layer (18). Due to surface defects of the active layer (18) caused by the application of the etching mask (20), particularly localized short circuits between the interface layer (20) and the conductive pad (14) of the photodiode forming the image pixel, the acquired image-saturated image pixel (32), corresponding to the white image pixel of FIG. 5, can be observed.

[0059] When the etching mask (20) is formed as a resin layer (22), the step of removing the etching mask (20) must be performed by forming an opening (26) in the active layer (18) and then, for example, immersing the structure containing the etching mask (20) in a chemical bath. However, the removal of the etching mask (20) must not cause etching in the active layer (18), which may introduce restrictions on the composition of the chemical bath. As a result, it may be difficult to ensure complete removal of the resin etching mask, which may cause the presence of unwanted residues on the active layer (18).

[0060] FIG. 6 illustrates an image obtained when the optoelectronic device (5) corresponds to an image sensor and the etching mask (20) is made of resin. The obtained image includes traces (34) reflecting the presence of residue on the active layer (18).

[0061] FIGS. 7 to 11 are simplified partial cross-sectional views of structures obtained in successive steps of an embodiment of a method for manufacturing a photoelectronic device (35).

[0062] Figure 7 shows the structure obtained after the following steps:

[0063] - A step of having a support (40) including an upper surface (42);

[0064] - For each optoelectronic component, a step of forming a first conductive pad or first conductive track (44) and a second conductive pad or second conductive track (45) on the surface (42) of the support (40), wherein two first pads (44) and two second pads (45) are shown in FIG. 7, and each optoelectronic component is associated with one of the first pads (44) and one of the second pads (45);

[0065] - A step of forming an interface layer (46) on each conductive pad (44, 45);

[0066] - A step of depositing an active organic layer (47) over the entire surface (42) and, in particular, covering the conductive pads (44, 45);

[0067] - A step of depositing an interface layer (48) on the entire active layer (47) in contact with the active layer (47).

[0068] Layers (46, 47, 48) can each be deposited by liquid deposition. In particular, methods such as spin coating, spray coating, heliography, slot-die coating, blade coating, flexography, silk screening, or dip coating (particularly for layer (46)) may be used. As a variation, layers (47, 48) may be deposited by cathode sputtering or evaporation. Depending on the deposition method performed, a step of drying the deposited material may be provided.

[0069] According to one embodiment, the support (40) may correspond to an integrated circuit comprising, for example, a semiconductor substrate made of single-crystal silicon, and inside and on top thereof, an insulating gate field-effect transistor, also called a MOS transistor, for example, an N-channel and P-channel MOS transistor, and an insulating layer stack covering the substrate, the transistor, and the conductive track are formed, and a conductive via is formed within the stack to electrically connect the transistor and the pad. The integrated circuit (40) may have a thickness in the range of 100 μm to 775 μm, preferably 200 μm to 400 μm. According to another embodiment, the support (40) may be made of a dielectric material. The support (40) is a rigid support, for example, particularly made of glass, or a flexible support, for example, made of a polymer or metal material. Examples of polymers include polyethylene naphthalene (PEN), polyethylene terephthalate (PET), polyimide (PI), and polyetheretherketone (PEEK). The thickness of the support (40) is, for example, 20 μm to 1 cm, for example, about 125 μm. If the radiation of interest emitted or captured by the photoelectronic component must pass through the support (40), the support may be transparent.

[0070] According to an embodiment, the material forming the conductive pads (44, 45) is selected from the group comprising the following components:

[0071] - Conductive oxides such as tungsten oxide (WO3), nickel oxide (NiO), vanadium oxide (V2O5) or molybdenum oxide (MoO3), particularly transparent conductive oxides (TCO), particularly indium tin oxide (ITO), aluminum zinc oxide (AZO), gallium zinc oxide (GZO), multilayer ITO / Ag / ITO structures, multilayer ITO / Mo / ITO structures, multilayer AZO / Ag / AZO structures, or multilayer ZnO / Ag / ZnO structures;

[0072] - Titanium nitride (TiN) and;

[0073] - Metals or metal alloys, e.g., silver (Ag), gold (Au), lead (Pb), palladium (Pd), copper (Cu), nickel (Ni), tungsten (W), molybdenum (Mo), aluminum (Al), chromium (Cr), or an alloy of magnesium and silver (MgAg);

[0074] - Conductive polymers, in particular PEDOT:PSS polymers which are mixtures of poly(3,4)-ethylenedioxythiophene and sodium polystyrene sulfonate, or polyaniline;

[0075] - Carbon, silver and / or copper nanowires;

[0076] - Graphene and;

[0077] - A mixture of at least two of these substances.

[0078] If the radiation of interest emitted or captured by the photoelectronic component must cross the support (40), the pads (44, 45) may be transparent to the radiation of interest.

[0079] The active layer (47) comprises at least one organic material and may comprise a stack or mixture of multiple organic materials. The active layer (47) may comprise a mixture of an electron donor polymer and an electron acceptor molecule. The thickness of the active layer (47) may be in the range of 50 nm to 2 µm, for example, about 300 nm.

[0080] The active layer (47) may include small molecules, oligomers, or polymers. These may be organic or inorganic materials. The active layer (47) may form a volumetric heterojunction by including a bipolar semiconductor material, or a mixture of an N-type semiconductor material and a P-type semiconductor material, for example in the form of a stacked layer or a nanometer-scale close mixture.

[0081] Examples of P-type semiconductor polymers capable of forming an active layer (47) include poly(3-hexylthiophene) (P3HT), poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4,7-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT), poly[(4,8-bis-(2-ethylhexyloxy)-benzo[1,2-b;4,5-b']dithiophene)-2,6-diyl-alt-(4-(2-ethylhexanoyl)-thieno[3,4-b]thiophene))-2,6-diyl] (PBDTTT-C), poly[2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylenevinylene] (MEH-PPV), or There is poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)-alt-4,7(2,1,3-benzothiadiazole)](PCPDTBT).

[0082] Examples of N-type semiconductor materials capable of forming an active layer (47) include fullerenes, particularly C60, [6,6]-phenyl-C 61 -methyl butanoate (

[60] PCBM), [6,6]-phenyl-C 71 There are nanocrystals that can form methyl butanoate (

[70] PCBM), perylene diimide, zinc oxide (ZnO), or quantum dots.

[0083] The interface layer (48) may correspond to an electron injection layer or a hole injection layer. The work function of the interface layer (48) may block, collect, or inject holes and / or electrons depending on whether the interface layer acts as a cathode or an anode. More specifically, if the interface layer (48) acts as an anode, it corresponds to a hole injection and electron blocking layer. The work function of the interface layer (48) is 4.5 eV or higher, preferably 4.8 eV or higher. If the interface layer (48) acts as a cathode, it corresponds to an electron injection and hole blocking layer. The work function of the interface layer (48) is 4.5 eV or lower, preferably 4.2 eV or lower. If the radiation of interest emitted or captured by the active layer (47) must pass through the interface layer (48), the interface layer (48) is transparent to the radiation of interest. The thickness of the oxide layer (48) may be in the range of 10 nm to 2 µm, for example, about 300 nm.

[0084] When the interface layer (48) acts as an electron injection layer, the material forming the interface layer (48) is selected from the group including the following:

[0085] - Metal oxides, especially titanium oxide or zinc oxide;

[0086] - Host / molecular dopant systems, in particular with Novaled products under the trade names NET-5 / NDN-1 or NET-8 / MDN-26;

[0087] - A conductive or doped semiconductor polymer, e.g., a PEDOT:tosylate polymer which is a mixture of poly(3,4)-ethylenedioxythiophene and tosylate;

[0088] - Polyethyleneimine (PEI) or ethoxylated, propoxylated, and / or butoxylated polyethyleneimine (PEIE);

[0089] - Carbonates, for example, CsCO3 and;

[0090] - Polymeric electrolytes, e.g., poly[9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene-alt-2,7-(9,9-dioctifluorene)](PFN), poly[3-(6-trimethylammoniumhexyl]thiophene (P3TMAHT) or poly[9,9-bis(2-ethylhexyl)fluorene]-b-poly[3-(6-trimethylammoniumhexyl]thiophene (PF2 / 6-b-P3TMAHT);

[0091] - A mixture of two or more of these substances.

[0092] When the interface layer (48) acts as a hole injection layer, the material forming the interface layer (48) may be selected from the group comprising the following components:

[0093] - Conductive or coated semiconductor polymers, in particular Sigma-Aldrich trademarks Plexcore OC RG-1100, Plexcore OC RG-1200, PEDOT:PSS polymers or polyaniline;

[0094] - Molecular host / dopant systems, in particular products marketed under the trade names NHT-5 / NDP-2 or NHT-18 / NDP-9 by Novaled;

[0095] - Tungsten oxide (WO3) and;

[0096] - Polymer electrolytes, for example, Nafion and;

[0097] - Metal oxides, e.g., molybdenum oxide, vanadium oxide, ITO, or nickel oxide;

[0098] - A mixture of two or more of these substances.

[0099] FIG. 8 illustrates a structure obtained after forming an etching mask (50) on an interface layer (48). According to one example, the etching mask (50) is obtained by depositing a resist layer (52) on the interface layer (48) and forming an opening (54) in the photosensitive layer (52) by photolithography techniques to expose the interface layer (48) particularly at the level of the second pad (45). According to another example, the etching mask (520) is obtained by directly depositing a resin block at a desired location on the interface layer (48) by, for example, inkjet, heliography, silk screening, flexography, or nanoimprint. In this case, there is no photolithography step. According to another example, the etching mask (50) is a rigid mechanical part that includes the opening (54) and is applied to the interface layer (48).

[0100] FIG. 9 illustrates a structure obtained after etching an opening (56) in the interface layer (48) in alignment with the opening (54) and etching an opening (58) in alignment with the opening (56) in the active layer (47) in order to expose a second pad (45) in particular. In this example, the openings (56, 58) each define two active layers (60) associated with a photoelectronic component, and each active region (60) covers a first associated pad (44). Each etching may be reactive ion etching (RIE) or chemical etching.

[0101] FIG. 10 illustrates a structure obtained after the removal of an etching mask (50). When the etching mask (50) is made of resin, the removal of the etching mask (50) can be achieved by any stripping method, for example, by immersing a structure containing the etching mask (50) in a chemical bath or by RIE etching.

[0102] FIG. 11 illustrates a structure obtained after forming a conductive connecting element (62) that, for each active region (60), preferably contacts the interface layer (48) and covers the second pad (45), and at least partially covers the interface layer (48) and the associated second pad (45). The connecting element (62) may be manufactured from one of the conductive materials of the previously mentioned list of materials for the interface layer (48). The connecting element (62) may be manufactured from the same material as the interface layer (48) or from a different material from the interface layer (48). When the interface layer (48) is manufactured from a non-conductive material, the connecting element (62) preferably completely covers the interface layer (48). According to one embodiment, particularly when the interface layer (48) is conductive and the connecting element (62) partially covers the interface layer (48), the interface layer (48) may be transparent to the radiation of interest and the connecting element (62) may be opaque to the radiation of interest. The maximum thickness of the connecting element (62) may be in the range of 10 nm to 2 µm.

[0103] According to the material forming the pads (44, 45) and the connecting element (62), the method of forming the connecting element (62) may correspond to a so-called addition process by direct printing of a fluid or viscous composition containing a material forming a connecting track at a desired location, for example, inkjet printing, heliography, silk screening, flexography, spray coating, drop-casting, or nanoimprinting. According to the material forming the pads (44, 45) and the connecting element (62), the method of forming the connecting element (62) may correspond to a so-called subtraction method, where the material forming the connecting track is deposited over the entire structure, and then the unused portion is removed, for example, by photolithography, laser ablation, or lift-off methods. According to the material under consideration, deposition over the entire structure may be performed, for example, by liquid deposition, cathode sputtering, or evaporation. Methods such as spin coating, spray coating, heliography, slot-die coating, blade coating, flexography, or silk screening may be particularly utilized. Depending on the deposition method performed, a step of drying the deposited material may be provided.

[0104] Advantageously, the step of defining the active area (60) implements an etching mask (50) applied to the interface layer (48) rather than the active layer (47). By doing so, the surface of the active layer (47) in contact with the interface layer (48) is not degraded by the etching mask (50). Additionally, the removal of the etching mask (50) may not result in the presence of residue in contact with the interface between the active layer (47) and the interface layer (48). Furthermore, when the etching mask (50) is made of a resist, there are fewer constraints on the choice of treatment performed for the removal of the etching mask (50) due to the reduced sensitivity of the interface layer (48).

[0105] FIGS. 12 to 16 are simplified partial cross-sectional views of a structure obtained in successive steps of another embodiment of a method for manufacturing a photoelectronic device (35).

[0106] FIG. 12 illustrates a structure obtained after the step of forming conductive pads (44, 45) on the surface (42) of a support (40) and forming an interface layer (46) on the conductive pads (44, 45), wherein only one conductive pad (44) and one conductive pad (45) are illustrated in FIG. 12 to 16.

[0107] FIG. 13 illustrates a structure obtained after the step of forming a sacrificial block (64) on each second pad (45), and a single block (64) is illustrated in FIG. 13. Each sacrificial block (64) is preferably made of a resist. The sacrificial block (64) can be formed by a photolithography step. According to one embodiment, as illustrated in FIG. 13, each sacrificial block (64) may have a trumpet-shaped form from the pad (45) on which it is placed, or may have a so-called cap-shaped profile. That is, it may have an upper portion with dimensions larger than the base in contact with the pad (45). According to one example, such a shape may be obtained by providing a step of curing the surface of the photosensitive layer used to form the block (64) particularly during the photolithography step, for example, by immersing the resin layer in an aromatic solvent such as chlorobenzene. According to another example, such a shape can be obtained during the resin layer development stage, and the resin is selected to have a development rate that varies along a direction perpendicular to the resin layer, and the resin layer has stronger resistance to development on its free upper surface. According to an embodiment, the dimensions of the base of the block (64) are larger than the dimensions of the pad (45) to ensure that the block (64) covers the entire pad (45).

[0108] FIG. 14 illustrates a structure obtained after the deposition step of the active layer (47) and the interface layer (48) over the entire structure illustrated in FIG. 13. The thickness of each portion of the sacrificial block (64) placed on the interface layer (46) is preferably greater than the sum of the thicknesses of the active layer (47) and the interface layer (48). The stack of the active layer (47) and the interface layer (48) extends over the pads (44, 45), over the surface (42) of the support (40) between the pads (44, 45), and over the upper surface of each sacrificial block (64). The stack forming method is preferably a directional deposition method in which the stack is not deposited on at least a portion of the sidewalls of the block (64) due to the trumpet-shaped block, which is wider at the top than at the bottom of the block (64).

[0109] FIG. 15 illustrates a structure obtained after the step of removing the sacrificial block (64). According to one embodiment, this is achieved by immersing the structure shown in FIG. 14 in a bath containing a solvent that selectively dissolves the sacrificial block (64) without dissolving the interface layer (48). Thus, an opening (56) is formed in the interface layer (48) and an opening (58) is formed in the active layer (47) defining the active region (60).

[0110] FIG. 16 shows a structure obtained after forming a connecting element (62) that partially covers the interface layer (48) and covers the second related pad (45) for each active area (60) in contact with the interface layer (48) and the interface layer (46) covering the second pad (45).

[0111] FIG. 17 is a simplified partial plan view having transparency of an embodiment of a component (35) corresponding to an organic photodiode. In this embodiment, the stack including the active region (60) and the interface layer (48) has a circular shape when viewed in the plan view.

[0112] FIGS. 18 to 24 are simplified partial cross-sectional views of a structure obtained in successive steps of an embodiment of a method for manufacturing an optoelectronic device comprising a sensor having an organic photodiode and a MOS transistor.

[0113] FIG. 18 is a partially simplified cross-sectional view of an example of an integrated circuit (68) including an array of MOS transistors, and six readout circuits (70) having MOS transistors are schematically illustrated as rectangles in FIG. 18 to 24. According to an embodiment, the integrated circuit (68) is formed by conventional techniques in microelectronics. Conductive pads are formed on the surface of the integrated circuit (68). Among the conductive pads, a pad (72) formed in a region (74) of the integrated circuit (68) and used as a lower electrode for an organic photodiode, a single pad (76) (illustrated in FIG. 18 to 24) to be used for biasing the upper electrode of the photodiode outside the region (74), for example, around the circuit (68), and a single pad (78) (illustrated in FIG. 18 to 24) to be used for biasing the integrated circuit (68) can be distinguished.

[0114] Typically, the integrated circuit (68) may include a semiconductor substrate made of, for example, single-crystal silicon, and an insulating gate field-effect transistor, also called a MOS transistor, for example, an N-channel and P-channel MOS transistor, and an insulating layer stack covering the substrate and the readout circuit (70) are formed on the inside and on top thereof, and conductive tracks and conductive vias are formed in the stack to electrically couple the readout circuit (70) and pads (72, 76, 78).

[0115] FIG. 19 illustrates a structure obtained after forming on each pad (72) of the organic interface layer (80). The formation method used may additionally cause the formation of an organic layer on pads (76, 78) not shown in FIG. 19. The interface layer (80) may be prepared from cesium carbonate (CsCO3), metal oxides, particularly zinc oxide (ZnO), or a mixture of at least two of these compounds. The interface layer (80) may comprise a self-assembled monolayer or polymer, for example, polyethyleneimine, ethoxylated polyethyleneimine, or poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7)-fluorene)-alt-2,7-(9,9-dioctylfluorene)]. The thickness of the interface layer (80) is preferably in the range of 0.1 nm to 1 µm. The interface layer (80) can be physically grafted onto the pad (72) (and possibly 76 and 78) that directly provides the structure shown in FIG. 19. As a variation, the interface layer (80) can be deposited over the entire structure shown in FIG. 18 and then etched outside the pad (72) to provide the result shown in FIG. 19. According to another variation not shown, the interface layer (80) can be deposited over the entire structure shown in FIG. 18, and since this layer has very low transverse conductivity, it does not need to be removed outside the pads (72, 76, 78).

[0116] FIG. 20 illustrates a structure obtained after forming an active organic layer (82) over the entire structure shown in FIG. 19, and an active region of the photodiode will be formed during operation. The active layer (82) may have the same composition as the active layer (47).

[0117] FIG. 21 illustrates a structure obtained after depositing an interface layer (84) on an active layer (82). The interface layer (84) may have the same composition as the interface layer (48).

[0118] FIG. 22 illustrates a structure obtained after depositing a resist layer (86) on an interface layer (84) by photolithography technology to expose an interface layer (84) at the level of a pad (76) and forming an opening (88) (a single opening 88 shown in FIG. 22) in the resist layer (86).

[0119] FIG. 23 illustrates a structure obtained after etching an opening (90) of an interface layer (84) in alignment with an opening (88) of a photosensitive layer (86), and etching an opening (92) of an active layer (82) in alignment with an opening (90) of the interface layer (84) to expose a pad (76).

[0120] FIG. 24 illustrates a structure obtained after removing the photosensitive layer (86) and depositing a connecting layer (94) over the entire structure. The connecting layer (94) may have the same composition as the connecting element (62) in particular, in contact with the pad (76).

[0121] The method may include a subsequent step of etching the connecting layer (94) and forming an encapsulation layer that covers the entire structure.

[0122] The structure includes an array of organic photodiodes (96) forming an optical sensor in layer (74), and each photodiode (96) is formed by a portion of organic layers (82, 84) facing one of the pads (72). In the example of FIG. 24, six organic photodiodes (96) are shown. In practice, this array is positioned vertically in line with a read circuit (70) that can be used to read and control the photodiodes (96) during operation. In this embodiment, layer (80) is shown as discontinuous at the level of the photodiodes (96), whereas the organic layers (82, 84) are shown as continuous at the level of the photodiodes (96). As a variation, the interface layer (80) may be continuous at the level of the photodiodes (96). The thickness of the stack may be in the range of 300 nm to 1 µm, preferably 300 nm to 500 nm.

[0123] Various embodiments and variations have been described. Those skilled in the art will understand that specific features of these various embodiments and variations may be combined and that other variations may arise for those skilled in the art. Finally, the actual realization of the described embodiments and variations is within the capability of those skilled in the art based on the functional indications given above.

Claims

Claim 1 A method for manufacturing an optoelectronic device (35), comprising the following consecutive steps: a) forming first and second electrically conductive pads (44, 45) on a support (40); b) depositing an active organic layer (47) covering the first and second electrically conductive pads; c) depositing a first interface layer (48) on the active organic layer in contact with the active organic layer; and d) forming a first opening (56) in the first interface layer (48) and forming a second opening (58) in the active organic layer (47) in alignment with the first opening to expose the second electrically conductive pad; e) forming a second interface layer (62) extending at least partially from the first and second openings, wherein the second interface layer is in contact with the first interface layer and the second electrically conductive pad, and the first interface layer (48) and / or the second interface layer (62) comprises: - a host / molecular dopant system; - a conductive or doped semiconductor polymer; - a carbonate; - a polymer electrolyte;- comprising at least one compound selected from a group including a mixture of two or more of these materials, and the method of manufacturing the optoelectronic device (35) further comprises the step of forming a lower interface layer (46) on each of the first and second electrically conductive pads (44, 45) between step a) and step b), wherein in step d), the second opening (58) is formed to expose the lower interface layer (46) disposed on the second electrically conductive pad (45) and the side of the second electrically conductive pad (45), and in step e), the second interface layer (62) is formed to contact the side of the second electrically conductive pad (45) exposed by the second opening (58) while covering the lower interface layer (46) exposed by the second opening (58), and a portion of the second interface layer (62) is disposed between the side of the second electrically conductive pad (45) and the side of the active organic layer.; Claim 2 A method according to claim 1, wherein the first interface layer (48) and / or the second interface layer (62) comprises polyethyleneimine (PEI) or ethoxylated, propoxylated, and / or butoxylated polyethyleneimine (PEIE). Claim 3 A method according to claim 1 or 2 in which the step of forming the first opening (56) and / or the second opening (58) is achieved by reactive ion etching. Claim 4 In claim 1, step d) includes the step of applying a mask (50) to the first interface layer (48), wherein the mask includes a third opening (54), and the first opening (56) is etched in alignment with the third opening. Claim 5 A method according to claim 1, wherein step d) includes the step of depositing a resist layer (52) on the first interface layer (48) and the step of forming a third opening (54) in the resist layer, wherein the first opening (56) is etched in alignment with the third opening. Claim 6 A method according to claim 1 or 2, comprising, between steps a) and b), a step of forming a resist block (64) facing the second electrically conductive pad (45), wherein the resist block comprises a top and sides, and after step c), a stack comprising the active organic layer (47) and the first interface layer (48) covers the top of the resist block but does not completely cover the sides, and the method comprises, in step d), a step of removing the resist block. Claim 7 As a photoelectronic device (35), - a support (40); - first and second electrically conductive pads (44, 45) on the support; - an active organic layer (47) covering the first and second electrically conductive pads; - a first interface layer (48) in contact with and covering the active organic layer; - a first opening (56) of the first interface layer (48) and a second opening (58) of the active organic layer (47) aligned with the first opening; - A second interface layer (62) extending at least partially from the first and second openings, comprising a second interface layer (62) in contact with the first interface layer and the second electrically conductive pad, wherein the first interface layer (48) and / or the second interface layer (62) comprises: - a host / molecular dopant system; - a conductive or doped semiconductor polymer; - a carbonate; - a polymer electrolyte; - comprising at least one compound selected from a group including a mixture of two or more of these materials, and the optoelectronic device (35) further comprises a lower interface layer (46) disposed on each of the first and second electrically conductive pads (44, 45), wherein the lower interface layer (46) disposed on the second electrically conductive pad (45) and the side of the second electrically conductive pad (45) are exposed by the second opening (58), and the second interface layer (62) covers the lower interface layer (46) exposed by the second opening (58) and contacts the side of the second electrically conductive pad (45) exposed by the second opening (58), and a portion of the second interface layer (62) is disposed between the side of the second electrically conductive pad (45) and the side of the active organic layer. Claim 8 In claim 7, the first interface layer (48) and / or the second interface layer (62) comprises polyethyleneimine (PEI) or ethoxylated, propoxylated, and / or butoxylated polyethyleneimine (PEIE) in an optoelectronic device. Claim 9 In claim 7 or 8, the first interface layer (48) and the second interface layer (62) are made of different materials in the optoelectronic device. Claim 10 In claim 7, the first and second conductive pads (44, 45) comprise at least one compound selected from the group comprising: a conductive oxide; a metal or metal alloy; a conductive polymer; carbon, silver and / or copper nanowires; graphene; and a mixture of at least two of these materials. Claim 11 In claim 7, the active organic layer (47) comprises a P-type semiconductor polymer and an N-type semiconductor material, wherein the P-type semiconductor polymer is poly(3-hexylthiophene) (P3HT), poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4,7-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT), poly[(4,8-bis-(2-ethylhexyloxy)-benzo[1,2-b;4,5-b']dithiophene)-2,6-diyl-alt-(4-(2-ethylhexanoyl)-thieno[3,4-b]thiophene))-2,6-diyl] (PBDTTT-C), poly[2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene-vinylene] (MEH-PPV), or A photoelectronic device in which the N-type semiconductor material is poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)-alt-4,7(2,1,3-benzothiadiazole)](PCPDTBT); and the N-type semiconductor material is fullerene, [6,6]-phenyl-C61-methylbutanoate ([60]PCBM), [6,6]-phenyl-C71-methylbutanoate ([70]PCBM), perylene diimide, zinc oxide, or a nanocrystal capable of forming quantum dots. Claim 12 In claim 7, the photoelectronic device is capable of emitting or capturing electromagnetic radiation, and the active organic layer (47) is a layer of the photoelectronic device in which the electromagnetic radiation is captured by the photoelectronic device or the electromagnetic radiation is emitted by the photoelectronic device.

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