METHOD FOR MANUFACTURING AN OPTOELECTRONIC DEVICE, CORRESPONDING DEVICE AND SYSTEM WITH THIS DEVICE

Description

Domaine technique

[0001] The present invention relates generally to the field of optoelectronic devices, and more particularly to a method of manufacturing an optoelectronic device combining a light emission function and an optical capture function. Technique antérieure

[0002] Various applications can benefit from an optoelectronic device that combines a light emission function and an optical capture function. Such a device can, for example, be used to create an interactive display screen.

[0003] Patent applications US 2021 / 0134654 A1 (May 6, 2021) and EP 3 667 728 A1 (June 17, 2020) represent the prior art in this field. The same applies to the scientific articles: "Recent Progress of Heterogeneous Integration for Semiconductor Materials and Microsystems", Eric ZX Liu et al., Solid-State and Integrated Circuit Technology, 2006, ICSICT'06, pages 520-523 (01-10-2006), and " High-Bandwidth InGaN Self-Powered Detector Arrays toward MIMO Visible Light Communication Based on Micro-LED Arrays", Liu Xiaoyan et al., ACS photonics 2019, 6, pages 3186-3195 (18-12-2019). Summary of the invention

[0004] An object of an embodiment is to overcome all or part of the disadvantages of known solutions for realizing an optoelectronic device combining a light emission function and an optical capture function.

[0005] The present invention covers a method for manufacturing an optoelectronic device, comprising the following steps: a) place an active stack of photosensitive diodes on a first substrate; b) transfer the active stack of photosensitive diodes onto a control integrated circuit previously formed in and on a second semiconductor substrate, then remove the first substrate; c) place an active stack of light-emitting diodes on a third substrate; and d) after steps b) and c), transfer the active stack of light-emitting diodes onto the active stack of photosensitive diodes, then remove the third substrate.

[0006] According to one embodiment, the active stack of photosensitive diode includes at least one inorganic semiconductor layer, for example in a III-V material, and the active stack of light-emitting diode includes at least one inorganic semiconductor layer, for example in a III-V material.

[0007] According to one embodiment, the active stack of photosensitive diodes comprises first, second and third semiconductor layers, the second layer being arranged between the first and third layers.

[0008] According to one embodiment, the process includes a P-type doping step of localized portions of the first layer, said portions defining anode regions of photosensitive diodes of the device.

[0009] According to one embodiment, the P-type doping step of the localized portions of the first layer is carried out after step b) and before step d).

[0010] According to one embodiment, the P-type doping step of localized portions of the first layer is implemented before step b).

[0011] According to one embodiment, the process further includes a step of forming connection metallizations on and in contact with said localized portions of the first layer.

[0012] According to one embodiment, at the end of step b), the active stack of photosensitive diodes extends continuously over the entire surface of the control integrated circuit.

[0013] According to one embodiment, at the end of step d), the active stack of light-emitting diodes extends continuously over the entire surface of the control integrated circuit.

[0014] According to one embodiment, the process further comprises, after step b) and before step d), a step of forming conductive vias through the active stack of photosensitive diodes.

[0015] According to one embodiment, the conductive vias are electrically connected to metal connection pads of the integrated circuit.

[0016] According to one embodiment, the method further comprises, after step d), a localized etching step of the active stack of light-emitting diodes so as to form in the active stack of light-emitting diodes a plurality of blocks each defining a light-emitting diode.

[0017] According to one embodiment, the process includes the formation of color conversion elements above at least some of the light-emitting diodes.

[0018] According to one embodiment, at least one of the light-emitting diodes is surmounted by a photoluminescent conversion element adapted to convert the light emitted by the light-emitting diode to a visible wavelength and at least one other of the light-emitting diodes is surmounted by a photoluminescent conversion element adapted to convert the light emitted by the light-emitting diode into light radiation in the sensitivity wavelength range of the active stack of photosensitive diodes, preferably infrared radiation.

[0019] According to one embodiment, at least one of the light-emitting diodes is not surmounted by a photoluminescent conversion element.

[0020] According to one embodiment, the photoluminescent conversion elements are made from quantum dots or perovskite materials.

[0021] According to one embodiment, the method comprises, after step d), a step of fixing a temporary support substrate on the side of the active stack of light-emitting diodes opposite the integrated circuit, followed by a step of cutting the assembly comprising the integrated circuit, the active stack of photosensitive diodes and the active stack of light-emitting diodes into a plurality of elementary chips.

[0022] According to one embodiment, the process further comprises a step of transferring and fixing the elementary chips onto a substrate for transferring the device, followed by a step of removing the temporary support substrate.

[0023] The present invention also covers an optoelectronic device comprising a carrier substrate and a plurality of elementary chips fixed and electrically connected to the carrier substrate, each elementary chip comprising a stack comprising, in order from the top face of the carrier substrate, a control integrated circuit formed in and on a semiconductor substrate, a photodetection stage comprising at least one photosensitive diode, and an emission stage comprising at least one light-emitting diode.

[0024] According to one embodiment, in each elementary chip, the photodetection stage is disposed between the control integrated circuit and the emission stage, and the photosensitive diode has an anode semiconductor layer disposed on the side of the emission stage and a cathode semiconductor layer disposed on the side of the control integrated circuit.

[0025] The present invention also covers a system comprising an optoelectronic device made by a process as defined above, and a light source adapted to emit light radiation in the sensitivity wavelength range of the active stack of photosensitive diodes, preferably infrared radiation.

[0026] According to one embodiment, the light source is a remote source.

[0027] According to one embodiment, the light source is integrated into the optoelectronic device and includes at least one light-emitting diode formed in the active stack of light-emitting diodes. Brève description des dessins

[0028] These features and advantages, as well as others, will be described in detail in the following description of particular embodiments, given by way of non-limiting example, in relation to the attached figures, among which: THE figures 1A, 1B, 1C , 1D, 1E, 1F, 1G , 1H, 1I et 1J are cross-sectional views illustrating successive stages of an example of a manufacturing process for an optoelectronic device according to a given embodiment; figures 2A, 2B, 2C, 2D , 2E, 2F, et 2G are cross-sectional views illustrating further successive steps in an example of a manufacturing process for an optoelectronic device according to one embodiment; the figure 3 schematically represents an example of a system comprising an optoelectronic device according to one embodiment; the figure 4 is a cross-sectional view schematically and partially illustrating another example of an optoelectronic device according to one embodiment; and the figure 5 is a cross-sectional view schematically and partially illustrating one variant of the device's implementation figure 4 . Description des modes de réalisation

[0029] The same elements have been designated by the same reference numerals in the different figures. In particular, structural and / or functional elements common to the different embodiments may have the same reference numerals and may have identical structural, dimensional and material properties.

[0030] For the sake of clarity, only the steps and elements necessary for understanding the described embodiments have been shown and are detailed. In particular, the fabrication of the photosensitive diodes, light-emitting diodes (LEDs), and integrated circuits for controlling the described devices has not been detailed, as the detailed fabrication of these components is within the grasp of a person skilled in the art based on the information provided in this description. Furthermore, the various applications of the described devices have not been detailed, as the described embodiments are compatible with all or most applications that could benefit from a device combining a light emission function and an optical capture function (photodetection).

[0031] Unless otherwise specified, when referring to two connected elements, this means directly connected without any intermediate elements other than conductors, and when referring to two coupled elements, this means that these two elements can be connected or linked through one or more other elements.

[0032] In the description that follows, when referring to absolute positional qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative positional qualifiers, such as the terms "above", "below", "superior", "inferior", etc., or to orientational qualifiers, such as the terms "horizontal", "vertical", etc., unless otherwise specified, reference is made to the orientation of the corresponding figures.

[0033] Unless otherwise specified, the expressions "approximately", "roughly", "about", and "on the order of" mean within 10%, preferably within 5%.

[0034] According to one aspect of an embodiment, the following steps are planned to be implemented to create an optoelectronic device combining a light emission function and a photodetection function: a) place an active stack of photosensitive diodes on a first substrate; b) transfer the active stack of photosensitive diodes onto a previously formed control integrated circuit in and onto a second semiconductor substrate, then remove the first substrate; c) place an active stack of LEDs on a third substrate; and d) after steps b) and c), transfer the active stack of LEDs onto the active stack of photosensitive diodes, then remove the third substrate.

[0035] THE figures 1A à 1J These are cross-sectional views illustrating successive stages of a non-limiting example of implementing such a process. Various variations are within the reach of a person skilled in the art, based on the information provided in this description.

[0036] There figure 1A schematically illustrates, in the upper part (A), the structure obtained after the steps of forming an active stack of photosensitive diode 103 on the upper face of a substrate 101.

[0037] The 103 stack is preferably a stack of inorganic semiconductor layers. The 103 stack comprises, for example, one or more layers of a type III-V semiconductor material. The 103 stack is, for example, an active stack of infrared or near-infrared photodiodes. Alternatively, the 103 stack is an active stack of visible-sensitive photodiodes. As an example, the 103 stack comprises, in order from the top face of the substrate 101, an unintentionally doped indium phosphide (InP) layer 103a, an absorption layer 103b of indium gallium arsenide (InGaAs), for example intrinsic or weakly doped of type N (for example on the order of 10 15< atoms / cm 3< ), and an N-type doped indium phosphide (InP) layer 103c. As an example, the N-type doping level of the 103c layer is between 10 16< and 10 18< atoms / cm 3< .In this example, layer 103b is in contact, by its lower face, with the upper face of layer 103a, and layer 103c is in contact, by its lower face, with the upper face of layer 103b.

[0038] Substrate 101 is, for example, made of indium phosphide. Layers 103a, 103b, and 103c can be formed successively by epitaxy on the upper surface of substrate 101. Substrate 101 is then a growth substrate. A buffer layer, not shown, for example made of indium phosphide, can optionally interface between substrate 101 and layer 103a. The buffer layer is, for example, in contact, via its lower surface, with the upper surface of substrate 101, and, via its upper surface, with the lower surface of layer 103a. The buffer layer can also be formed by epitaxy from the upper surface of substrate 101, before the formation of layers 103a, 103b, and 103c.

[0039] Alternatively, instead of forming the active stack of photosensitive diodes 103 by epitaxy on the upper surface of substrate 101, the active stack can be formed in reverse order on a growth substrate (not shown) and then transferred and fixed to substrate 101. In this case, layers 103c, 103b, and 103a are successively formed by epitaxy on one face of the growth substrate. A buffer layer, for example, of indium phosphide, can optionally interface between the growth substrate and layer 103c. Stack 103 is then fixed to the upper surface of substrate 101, for example, by direct bonding or molecular bonding of the lower face of layer 103a to the upper face of substrate 101. Alternatively, other bonding methods can be used.The growth substrate, and, where applicable, the buffer layer interfacing between the growth substrate and layer 103c, are then removed to provide access to the upper surface of layer 103c. In this variant, substrate 101 is a support substrate, for example made of silicon, or any other suitable material to serve as a receiving support for the active stack 103.

[0040] There figure 1A further illustrates, in the upper part (A), a step of deposition of a dielectric layer 105, for example of silicon oxide or silicon nitride, on and in contact with the upper face of the upper layer 103c of the active stack of photosensitive diode 103. In this example, the dielectric layer 105 extends continuously and with a substantially uniform thickness over the entire upper surface of the layer 103c.

[0041] There figure 1A further illustrates schematically, in the intermediate part (B), the structure obtained at the end of the steps of forming an active stack of LEDs 113 on the upper face of a substrate 111.

[0042] Stack 113 is preferably a stack of inorganic semiconductor layers. Stack 113 comprises, for example, one or more layers of a type III-V semiconductor material. Stack 113 is, for example, an active LED stack adapted to emit visible light, for example, predominantly blue light. As an example, stack 113 is an active gallium nitride (GaN) LED stack. As an example, stack 113 comprises, in order from the top face of substrate 111, an N-doped semiconductor layer 113a, forming a cathode layer of the LED stack, an active layer 113b, and a P-doped semiconductor layer 113c, forming an anode layer of the LED stack. Layer 113a is, for example, made of gallium nitride.The active layer 113b, for example, is a multi-quantum-well stack (not detailed in the figure), consisting of alternating semiconductor layers of a first material, for example a type III-V material, and semiconductor layers of a second material, for example a type III-V material. Each layer of the first material is sandwiched between two layers of the second material, defining a quantum well. The layer 113c, for example, is made of gallium nitride. The active layer 113b, for example, is in contact, on its lower face, with the upper face of the layer 113a. The layer 113c, for example, is in contact, on its lower face, with the upper face of the active layer 113b.

[0043] The substrate 111 is, for example, made of silicon, sapphire, or gallium nitride. As an example, layers 113a, 113b, and 113c are successively formed by epitaxy on the upper surface of substrate 111. A buffer layer, not shown, may optionally interface between the upper surface of substrate 111 and the lower surface of layer 113a.

[0044] At this stage, each of the layers of the active stack of photosensitive diode 103 extends, for example, continuously and with a substantially uniform thickness over the entire upper surface of the substrate 101. In addition, each of the layers of the active stack of LEDs 113 extends, for example, continuously and with a substantially uniform thickness over the entire upper surface of the substrate 111. The substrates 101 and 111 have, for example, substantially the same lateral dimensions.

[0045] There figure 1A The intermediate portion (B) further illustrates a step of depositing a conductive layer 115 onto and in contact with the upper surface of the semiconductor layer 113c. The layer 115 forms an ohmic contact with the semiconductor material of the layer 113c. The layer 115 is, for example, made of aluminum, nickel, or a transparent conductive oxide, such as indium tin oxide (ITO). At this stage, the metallic layer 115 extends continuously and with a substantially uniform thickness over the entire upper surface of the layer 113c. The layer 115 may also function as an optical reflector. For example, the layer 115 may comprise two superimposed layers, one providing the ohmic contact function with the semiconductor material of the layer 113c and the other the optical reflector function.

[0046] There figure 1A Figure 151, shown schematically in the lower part (C), illustrates a control integrated circuit 151 previously formed in and on a semiconductor substrate, for example, silicon. The control integrated circuit 151 includes control and readout circuits for the LEDs and photodiodes of the device. For example, the integrated circuit 151 includes a set of elementary control and readout cells, allowing each LED and each photodiode of the device to be individually controlled and read. The integrated circuit 151 is, for example, a CMOS (Complementary Metal Oxide Semiconductor) circuit. In this example, the circuit 151 includes a plurality of metal connection pads 153 arranged on its upper face.

[0047] There figure 1A further illustrates, in the upper part (C), a step of deposition of a dielectric layer 107, for example of silicon oxide or silicon nitride, for example of the same material as the layer 105, on and in contact with the upper face of the control integrated circuit 151. In this example, the dielectric layer 107 extends continuously and with a substantially uniform thickness over the entire upper surface of the control integrated circuit 151.

[0048] There figure 1B illustrates the structure obtained after a step of transferring and fixing the active stack of photosensitive diodes 103 onto the control integrated circuit 151, and then removing the substrate 101. During this step, the active stack of photosensitive diodes 103 is transferred onto the integrated circuit 151, using the substrate 101 as a support handle. On the figure 1B , the structure comprising the substrate 101 and the stack 103 is flipped with respect to the orientation of the figure 1A The stack-up 103 is then fixed to the integrated circuit 151. In this example, the stack-up 103 is fixed by direct bonding or molecular bonding of the lower face (in the orientation of the figure 1B , corresponding to the upper face in the orientation of the figure 1A ) of layer 105, on the upper face (in the orientation of the figure 1B , corresponding to the upper face in the orientation of the figure 1A ) of layer 107. Alternatively, other fixing methods may be used. The substrate 101 is then removed, for example by grinding and / or chemical etching, so as to provide access to the top face of layer 103a. At this stage, each of the layers of the active stack of photosensitive diodes 103 extends, for example, continuously and with a substantially uniform thickness, over the entire surface of the control integrated circuit 151. It should be noted that, in this example, the active stack 103 is unstructured and has not undergone any localized processing steps before the transfer step. Thus, the transfer step does not require precise alignment.

[0049] There figure 1C illustrates a step in the deposition of a dielectric layer 121, for example of silicon nitride or silicon oxide, onto the upper surface of the layer 103a, for example in contact with the upper surface of the layer 103a. The layer 121 is deposited, for example, by a plasma-enhanced chemical vapor deposition (PECVD) process. The layer 121 is deposited, for example, continuously and with a uniform thickness over the entire upper surface of the layer 103a. figure 1C It further illustrates a step in the formation of localized through-holes 123 in the dielectric layer 121. The holes 123 are formed, for example, by photolithography and etching. The holes are arranged opposite future P-type contact areas corresponding to the anode regions of the photosensitive diodes of the device.

[0050] There figure 1D This illustrates a P-type doping step of localized regions 125 of layer 103a, located opposite the openings 123. The doping of the regions 125 can be achieved by diffusion or implantation of P-type dopants, for example zinc (Zn) or beryllium (Be), opposite the openings 123. An activation annealing of the dopants can then be performed. For example, the activation annealing can be a surface laser annealing, which avoids damaging the integrated circuit components 151 or compromising the bond quality between the integrated circuit 151 and the active stack of photosensitive diodes 103. The P-type doped regions 125 form the anode regions of the photosensitive diodes of the device. In this example, the regions 125 extend over the entire thickness of the layer 103a, and come into contact, by their lower face, with the upper face of the absorption layer 103b.

[0051] There figure 1E This illustrates a step in the formation of contact-re-establishment metallizations 127 in the openings 123. Each metallization 127 individually contacts the underlying region 125 through its corresponding opening 123. As an example, a metallic layer is first deposited continuously over the entire upper surface of the structure, i.e., on and in contact with the upper face of the dielectric layer 121 and in the openings 123, and then removed by photolithography and etching so as to retain only the metallizations 127. In this example, each metallization 127 constitutes an anode electrode of a photosensitive diode 171 of the device.

[0052] There figure 1F illustrates the structure obtained at the end of steps of formation of laterally insulated conductive vias 129, passing through the active stack of photosensitive diode 103. More particularly, in this example, the conductive vias 129 pass through layer 121, layers 103a, 103b and 103c of the stack 103, the insulating layers 105 and 107, and each emerge onto and in contact with the top face of a metal pad 153 of the control integrated circuit. The fabrication of the vias 129 includes an etching step, starting from the upper face of the insulating layer 121, of through-holes in the stack formed by the layers 107, 105, 103c, 103b, 103a, and 121. The openings are formed, for example, by plasma etching, such as ICP (Inductively Coupled Plasma). A passivation step of the sides of the openings is then carried out.In this step, a layer 131 of an insulating material, for example silicon oxide, is deposited on the side walls and bottom of the openings. A vertical anisotropic etching step can then be carried out to remove the insulating layer from the bottom of the openings, without removing it from the side walls. The openings are then filled with metal to form the conductive vias 129.

[0053] Before or after the formation of the conductive vias 129, one or more conductive vias (not visible in the figures) for re-establishing contact on the cathode layer 103c of the photosensitive diode stack may be formed. These cathode re-establishment vias are similar to the vias 129 shown in the figure 1F Namely, they pass through layer 121, layers 103a, 103b, and 103c of the stack 103, the insulating layers 105 and 107, and open onto and are in contact with the upper face of a metal pad 153. The cathode contact vias differ from the vias 129 in that they are in contact, laterally, with the sides of the cathode semiconductor layer 103c of the photosensitive diode stack. The cathode contact vias, on the other hand, are laterally isolated from the anode semiconductor layer 103a by a lateral insulating layer. To produce the lateral insulation layer covering the sides of the anode semiconductor layer 103a and not covering the sides of the cathode semiconductor layer 103c, one possibility is to deposit the insulating passivation material by spraying, with an angle of incidence, so that the insulating material is deposited only on an upper part of the walls of the via opening.The deposit depth can be adjusted by changing the applied tilt angle. Alternatively, the cathode contact vias can be fabricated in two successive etching steps. In the first etching step, an opening is formed through the anode semiconductor layer 103a and all or part of the absorption layer 103b. An insulating passivation layer is then deposited on the lateral walls of the first opening. In the second etching step, a second opening is formed through the cathode semiconductor layer 103c, this second opening having smaller lateral dimensions than the first. Both the first and second openings are then filled with metal.

[0054] There figure 1G illustrates the structure obtained after a step of depositing a metallic layer 143 on the upper face of the structure of the figure 1F In this example, the metallic layer 143 extends continuously and with a substantially uniform thickness over the entire upper surface of the structure of the figure 1F In the example shown, prior to the deposition of the metallic layer 143, a planarization step of the upper surface of the structure is carried out, for example by a Damascus-type process. For this, an insulating layer 141, for example of silicon oxide, is deposited over the entire upper surface of the structure. figure 1F , over a thickness greater than the thickness of the portions of the metallizations 127 and 129 protruding from the upper face of the insulating layer 121. The insulating layer 141 is then planarized from its upper face, for example by chemical polishing, until access is granted to the upper face of the metallizations 127 and 129. This results in a flat upper surface with alternating insulating and metallic regions. The metallic layer 143 is then deposited on and in contact with this planarized surface. The metallic layer 143 is, for example, made of the same metal as the metallic layer 115 deposited on the upper face of the LED stack 113 figure 1A ).

[0055] There figure 1H illustrates the structure obtained after a step of transferring and fixing the active stack of LEDs 113 onto the upper face of the structure of the figure 1G , then removal of the substrate 111. During this step, the active LED stack 113 is transferred to the upper face of the structure of the figure 1G using substrate 111 as a support handle. On the figure 1H , the structure comprising the substrate 111, the stack 113 and the layer 115 is flipped with respect to the orientation of the figure 1A The stack 113 is then fixed to the structure of the figure 1G As an example, the 113 stack is fixed by direct bonding or molecular bonding of the lower face (in the orientation of the figure 1H , corresponding to the upper face in the orientation of the figure 1A ) of layer 115, on the upper face (in the orientation of the figure 1H , corresponding to the upper face in the orientation of the figure 1G ) of the upper metallic layer 143 of the structure of the figure 1G Preferably, the bonding is a SAB (Surface Activated Bonding) type bond, i.e., a direct bond in which the contacting surfaces are pre-activated by atomic bombardment. SAB has the advantage of being able to be carried out at low temperatures, for example, at room temperature. The substrate 111 is then removed, for example, by grinding and / or chemical etching, or by a laser peeling process, so as to provide access to the top face of layer 113a. At this stage, each of the layers of the active LED stack 113 extends, for example, continuously and with a substantially uniform thickness, over the entire surface of the active stack of the assembly. It should be noted that in this example, the active LED stack 113 is unstructured and has not undergone any localized processing steps before the transfer step. Thus, the transfer step does not require precise alignment.

[0056] There figure 1I This illustrates the structure obtained after a step of forming cathode contact metallizations 145 of the device's LEDs in openings through the active LED stack 113 and the metal layers 115 and 143. Each cathode contact metallization 145 extends vertically from the top face of the stack to the top face of a conductor via 129 of the device. Thus, each cathode contact metallization 145 is electrically connected, via the underlying conductor via 129, to a dedicated metal connection pad 153 of the control integrated circuit 151.

[0057] A localized etching step of layers 113a, 113b, 113c, 115, and 143 is first implemented to form the openings intended to receive the metallizations 145. A passivation step of the sides of the openings is then implemented. During this step, a layer 147 of an insulating material, for example, silicon oxide, is deposited on the lateral walls and at the bottom of the openings. A vertical anisotropic etching step can then be implemented to remove the insulating layer 147 from the bottom of the openings. The insulating layer 147 can also be removed, inside the openings, on the sides of an upper part of the cathode layer 113a of the LED stack 113. The insulating layer 147 is, however, retained, inside the openings, on the sides of layers 113b, 113c, 115 and 143. The openings are then filled with metal to form the metallizations 145.Thus, each metallization 145 is in contact with the N-type layer 113a of the active LED stack at the side walls of the aperture. Each metallization 145 is, however, laterally isolated from layers 113b, 113c, 115, and 143 by the insulating layer 147.

[0058] There figure 1J This illustrates the structure obtained after a localized etching step of the stack formed by the metal layers 143 and 115 and the active stack of LEDs 113. During this step, only sections 161 of the active stack of LEDs 113 are retained, corresponding respectively to the different LEDs 161 of the device. In this example, each LED section 161 includes a cathode contact metallization 145. The portion of the stack of metal layers 115 and 143 located under each LED 161 forms an anode electrode of the LED and is electrically connected to a dedicated pad 153 of the integrated circuit 151 via a via 129.

[0059] Apart from the LED arrays 161, the stack 113 and the metal layers 115 and 143 are completely removed, so as to expose the upper surface of the dielectric layer 141 and the underlying metallizations 129 and 127. In particular, in this example, the stack 113 and the layers 115 and 143 are removed opposite the photosensitive diodes 171 of the device.

[0060] A further step of passivating the sides of the LED 161, not detailed, may possibly be envisaged.

[0061] It should be noted that in the example shown, the anode electrodes 127 of the photosensitive diodes 171, and the anode electrodes 115, 143 and the cathode electrodes 145 of the LEDs 161 are all individually connected to connection pads 153 of the integrated circuit 151. The cathode electrode(s) of the photosensitive diodes 171 may be common to all the photosensitive diodes 171 of the device, and connected to the integrated circuit 151 at the periphery of the device, via cathode contact vias of the type described above.

[0062] As an alternative, the cathode electrodes of the LEDs 161 can be common to all the LEDs 161 of the device, and connected to the integrated circuit 151 at the periphery of the device, so as to limit the number of conductive vias 129 and pads 153. In another alternative, not shown, the cathode electrodes of the LEDs 161 and the photosensitive diodes 171 can be common.

[0063] Depending on the intended application, light conversion elements (not shown) may be arranged opposite LEDs 161, on their upper faces, to obtain, on the same device, emission pixels adapted to emit in different wavelength ranges, for example, red, green, and blue pixels. Furthermore, filtering elements (not shown) may be arranged opposite photosensitive diodes 171, on their upper faces, to obtain, on the same device, detection pixels adapted to detect radiation in different wavelength ranges.

[0064] The process described in relation to the figures 1A à 1J This method can be used to create monolithic microdisplays, combining an image display function with an optical capture function, for example, to create an interactive screen suitable for implementing face or shape recognition, motion detection, identification, etc. An advantage of the described method is that it allows for display and capture pixels with small lateral dimensions, thus achieving high display and capture resolutions. It should be noted that in the example described above, each pixel of the device comprises a photosensitive diode 171 and an LED 161. Alternatively, the resolution of the display device and the resolution of the optical sensor can be different. For example, the number of photosensitive diodes 171 in the device can be less than the number of LEDs 161.

[0065] As an alternative, the process described in relation to the figures 1A à 1J This technology can be used to create larger interactive display devices, such as television, computer, smartphone, or tablet screens. Such a device can comprise a plurality of elementary electronic chips arranged, for example, in a matrix configuration, on a single substrate. The elementary chips are fixed to the substrate and connected to electrical connection elements on the substrate for control. Each chip includes one or more LEDs 161, one or more photosensitive diodes 171, and a control circuit 151 for said LED(s) and photosensitive diode(s). Each chip corresponds, for example, to one pixel of the device.As an example, each chip includes three individually controllable LEDs 161, defining three sub-pixels respectively adapted to emit red light, green light and blue light, and a photosensitive diode 171 adapted to detect infrared or near-infrared radiation.

[0066] THE figures 2A à 2G are cross-sectional views illustrating successive stages of an example of a manufacturing process for such a device.

[0067] There figure 2A illustrates in a very schematic way a starting structure that corresponds to a structure of the type obtained by the process of figures 1A à 1J comprising a control integrated circuit stage 151, surmounted by a photodetection stage 201, itself surmounted by an emission stage 203. The photodetection stage 201 comprises a plurality of photosensitive diodes 171 (not detailed in the figures 2A à 2G ) individually controllable by integrated circuit 151. The emission stage comprises a plurality of LEDs 161 (not detailed on the figures 2A à 2G ) individually controllable by integrated circuit 151. On the figure 2A , only the electrical connection pads 153 of the integrated circuit 151, arranged on the side of the upper face of the integrated circuit 151, have been detailed.

[0068] There figure 2B illustrates a step in gluing the structure of the figure 2A on a temporary support substrate 210, for example silicon. The structure of the figure 2A is fixed to the support substrate 210 by its face opposite the control integrated circuit 151, i.e. by its lower face in the orientation of the figure 2B , corresponding to its upper face in the orientation of the figure 2A .

[0069] There figure 2C This illustrates an optional step in thinning the semiconductor substrate of integrated circuit 151, on its side opposite stages 201 and 203. As an example, integrated circuit 151 is initially formed in and on a SOI (Semiconductor On Insulator) substrate. The SOI substrate comprises, for example, a silicon substrate coated with an insulating layer, itself coated with a layer of monocrystalline silicon (not detailed in the figures). The components, particularly transistors, of integrated circuit 151 can be formed in and on the monocrystalline silicon layer of the SOI substrate. The thinning step of the figure 2C may consist of removing the support substrate from the SOI substrate, so as to retain only the single-crystal silicon layer and the insulating layer of the SOI substrate.

[0070] As an alternative, the integrated circuit 151 is formed in and on a solid silicon substrate, the thinning step then consisting of reducing the thickness of the substrate, for example by grinding, from its top face (in the orientation of the figure 2C ). An insulating passivation layer (not detailed in the figure) can then be deposited on the upper face of the thinned substrate.

[0071] There figure 2D illustrates a formation step, on the top side of the integrated circuit 151, of metal connection pads 221, connected to the connection pads 153 and / or to connection terminals of electronic components, for example MOS transistors, of the integrated circuit 151, by means of conductive vias not detailed in the figure, passing through the semiconductor substrate of the integrated circuit 151.

[0072] There figure 2E This illustrates a step in forming trenches 230 from the top surface of the integrated circuit 151, vertically traversing the integrated circuit 151, the detection stage 201, and the emission stage 203, and opening onto the top surface of the temporary support substrate 210. The trenches 230 laterally delimit a plurality of semiconductor chips 232 corresponding to the elementary pixel chips of the display device. The trenches 230 can be formed by plasma etching, sawing, or any other suitable cutting method.

[0073] THE figures 2F et 2G illustrate a step of fixing elementary chips 232 onto the upper face of the same transfer substrate 250 of the display device. The transfer substrate 250 comprises, on its upper face, a plurality of metal connection pads 252, intended to be fixed and connected electrically and mechanically to corresponding metal connection pads 221 of the elementary chips 232.

[0074] The structure of the figure 2E is returned ( figure 2F ) so as to place the metal connection pads 221 of elementary chips 232 opposite corresponding metal connection pads 252 of the transfer substrate 250. The opposite pads 221 and 252 are then fixed and electrically connected, for example by direct gluing, by welding, by means of microtubes, or by any other suitable method.

[0075] Once fixed to the transfer substrate 250, the elementary chips 232 are detached from the temporary support substrate 210, and the latter is removed ( figure 2G ). As an example, chip detachment is achieved by mechanical peeling or by peeling using a laser beam.

[0076] In the example shown, the pitch (center-to-center distance in front view) of the elementary chips 232 on the transfer substrate 250 is a multiple of the pitch of the elementary chips 232 on the temporary support substrate 210. Thus, only some of the elementary chips 232 (one out of two in the example shown) are transferred simultaneously from the temporary support substrate 210 to the transfer substrate 250. The other chips 232 remain attached to the temporary support substrate 210 and can be transferred later to another part of the transfer substrate 250 or to another transfer substrate 250.

[0077] Various embodiments and variations have been described. Those skilled in the art will understand that certain features of these various embodiments and variations could be combined, and other variations will become apparent to them. In particular, the embodiments described are not limited to the examples of materials and / or dimensions mentioned in this description.

[0078] Furthermore, in the example described in relation to the figures 1A à 1J The anode regions 125 and the anode metallizations 127 of the photosensitive diodes 171 are produced after the active stack of photosensitive diodes 103 is transferred to the integrated circuit 151. Alternatively, but not detailed in the figures, the anode regions 125 and the anode metallizations 127 of the photosensitive diodes 171 can be produced before the active stack of photosensitive diodes 103 is transferred to the active stack of LEDs 113. In this case, the layer order of the stack 103 is reversed compared to the example in the figure 1A The bonding of the active stack of photosensitive diodes 103 onto the integrated circuit 151 is then a hybrid bonding requiring alignment of the anode metallizations 127 of the photosensitive diodes with respect to the metallic connection pads 153 of the integrated circuit 151. However, an advantage is that the activation annealing of the dopants of the regions 125 can then be carried out before transferring the stack 103 onto the integrated circuit 151, which avoids any degradation of the integrated circuit 151 or of the bonding between the stack 103 and the integrated circuit 151 during annealing.

[0079] There figure 3 schematically represents an example of a system comprising an optoelectronic device 300 according to one embodiment.

[0080] The 300 device can be a monolithic micro-screen type device, for example produced by a process of the type described in relation to the figures 1A à 1J .

[0081] As an alternative, device 300 may be a larger device, for example produced by a process of the type described in relation to the figures 2A à 2G .

[0082] The 300 device combines an image display function and an optical capture function, for example to create an interactive screen suitable for implementing face or shape recognition, motion detection, identification, etc.

[0083] The system of the figure 3 It also includes a light source 310. The source 310 is adapted to emit light radiation within the sensitivity range of the photosensitive diodes 171 (not detailed on the figure 3 ) of device 300. As an example, source 310 is an infrared source, for example a laser source.

[0084] In operation, the source 310 illuminates a scene 320 from which an image is to be acquired. The light emitted by the source 310 is reflected by the scene 320 and sent back to the device 300. The photosensitive diodes 171 of the device 300 then allow the acquisition of an image of the scene 320 and / or the measurement of depth information relating to the scene 320.

[0085] In the example of the figure 3 The light source 310 is a remote source, that is to say, it is separate from the device 300. The control of the light source 310 and the control of the detection pixels of the device 300 are, for example, synchronized.

[0086] There figure 4 is a cross-sectional view schematically and partially illustrating another example of an optoelectronic device according to one embodiment.

[0087] In this example, the optoelectronic device incorporates a distributed light source emitting within the sensitivity range of the photodiodes 171, for example, an infrared source. This eliminates the need for the remote source 310 of the system. figure 3 .

[0088] The device of the figure 4 includes elements common to the device of the figure 1J These elements will not be detailed again below, and only the differences compared to the device of the figure 1J will be highlighted.

[0089] In the example of the figure 4 Two LEDs 161(a) and 161(b) of the device are shown, for example, identical or similar. LEDs 161(a) and 161(b) are suitable for emitting light in the same wavelength range, for example, predominantly blue light. However, the embodiments described are not limited to this particular example, and a person skilled in the art will be able to adapt the described embodiment in relation to the figure 4 to other LED emission colours 161.

[0090] In this example, the LED 161(a) is coated, on the side of its upper face, by a photoluminescent conversion element 181(a) adapted to convert the light emitted by the LED into visible light at another wavelength, for example into red or green light in the case of an LED emitting blue light.

[0091] As an example, in the case of LEDs emitting blue light, three types of visible light emission pixels can be provided, adapted to emit red light (by means of a photoluminescent conversion element converting the blue light emitted by the underlying LED into red light), green light (by means of a photoluminescent conversion element converting the blue light emitted by the underlying LED into green light), and blue light (without a conversion element).

[0092] The LED 161(b) is coated, on its upper face, with a photoluminescent conversion element 181(b) adapted to convert the light emitted by the LED into light radiation in the range of wavelengths detected by the photosensitive diodes 171 of the device, for example infrared radiation.

[0093] Thus, the LED 161(b) defines a PIR emissive pixel of a light source integrated into the optoelectronic device, adapted to cooperate with the photosensitive diodes 171 and replacing the source 310 of the system of the figure 3 .

[0094] As described previously, the device of the figure 4 can be a monolithic micro-screen type device, or a pixel of a larger device.

[0095] The number and repetition rate of the PIR pixels can be chosen according to the application's requirements. For example, the device may include fewer PIR pixels than visible pixels (defined by the 161(a) LEDs) of the same emission color. Preferably, the final device (monolithic microdisplay or extended device) comprises several PIR pixels distributed across its surface.

[0096] The conversion elements 181(a), 181(b) mounted on top of the LEDs 161(a), 161(b) are, for example, made from quantum dots or from perovskite materials, preferably inorganic perovskite materials, preferably epitaxially treated inorganic perovskite materials. The conversion elements based on perovskite materials are, for example, deposited by pulsed laser deposition (PLD).

[0097] There figure 5 is a cross-sectional view schematically and partially illustrating one variant of the device's implementation figure 4 .

[0098] The variant of the figure 5 differs from the example of the figure 4in that it further comprises opaque walls 191, for example made of resin, laterally separating the emitting pixels from each other and laterally separating the emitting pixels from the detection pixels. This makes it possible, in particular, to prevent light emitted by the PIR pixels from directly reaching the photosensitive diodes 171, without passing through the scene from which an image is to be acquired.

[0099] The scope of the present invention is defined by the following claims.

Claims

1. Optoelectronic device manufacturing method, comprising the steps of: a) arranging an active photosensitive diode stack (103) on a first substrate (101); b) transferring the active photosensitive diode stack (103) onto an integrated control circuit (151) previously formed inside and on top of a second semiconductor substrate, and then removing the first substrate (101); c) arranging an active light-emitting diode stack (113) on a third substrate (111); and d) after steps b) and c), transferring the active light-emitting diode stack (113) onto the active photosensitive diode stack (103), and then removing the third substrate (111).

2. Method according to claim 1, wherein the active photosensitive diode stack (103) comprises at least one inorganic semiconductor layer, for example, made of a III-V material, and wherein the active light-emitting diode stack comprises at least one inorganic semiconductor layer (113), for example, made of a III-V material.

3. Method according to claim 1 or 2, wherein the active photosensitive diode stack (103) comprises first (103a), second (103b), and third (103c) semiconductor layers, the second layer (103b) being arranged between the first (103a) and third (103c) layers.

4. Method according to claim 3, comprising a step of P-type doping of local portions (125) of the first layer (103a), said portions defining anode regions of photosensitive diodes (171) of the device.

5. Method according to claim 4, wherein said step of P-type doping of the local portions (125) of the first layer (103a) is implemented after step b) and before step d).

6. Method according to claim 4, wherein said step of P-type doping of the local portions (125) of the first layer (103a) is implemented before step b).

7. Method according to any of claims 4 to 6, further comprising a step of forming of connection metallizations (127) on top of and in contact with said local portions (125) of the first layer (103a).

8. Method according to any of claims 1 to 7, wherein, at the end of step b), the active photosensitive diode stack (103) continuously extends over the entire surface of the integrated control circuit (151).

9. Method according to any of claims 1 to 8, wherein, at the end of step d), the active light-emitting diode stack (113) continuously extends over the entire surface of the integrated control circuit (151).

10. Method according to any of claims 1 to 9, further comprising, after step b) and before step d), a step of forming of conductive vias (129) crossing the active photosensitive diode stack (103).

11. Method according to claim 10, wherein the conductive vias (129) are electrically connected to metal connection pads (153) of the integrated circuit (151).

12. Method according to any of claims 1 to 11, further comprising, after step d), a step of local etching of the active light-emitting diode stack (113) to form in the active light-emitting diode stack a plurality of tiles (161), each defining a light-emitting diode.

13. Method according to claim 12, comprising the forming of color conversion elements (181(a), 181(b)) above at least some of the light-emitting diodes (161(a), 161(b)).

14. Method according to claim 13, wherein at least one (161(a)) of said light-emitting diodes is topped with a photoluminescent conversion element (181(a)) adapted to converting the light emitted by the light-emitting diode into a visible wavelength and at least another one (161(b)) of said light-emitting diodes is topped with a photoluminescent conversion element (181(b)) adapted to converting the light emitted by the light-emitting diode into a light radiation in the wavelength range of sensitivity of the active photosensitive diode stack, preferably an infrared radiation.

15. Method according to claim 14, wherein at least one (161) of said light-emitting diodes is not topped with a photoluminescent conversion element.

16. Method according to any of claims 13 to 15, wherein said photoluminescent conversion elements (181(a), 181(b)) are formed based on quantum dots or on perovskite materials.

17. Method according to any of claims 1 to 12, comprising, after step d), a step of bonding of a temporary support substrate (210) on the side of the active light-emitting diode stack (113) opposite to the integrated circuit (151), followed by a step of cutting of the assembly comprising the integrated circuit (151), the active photosensitive diode stack (103), and the active light-emitting diode stack (113) into a plurality of elementary chips (232).

18. Method according to claim 13, further comprising a step of transfer and of bonding of said elementary chips (232) onto a transfer substrate (250) of the device, followed by a step of removal of the temporary support substrate (210) .

19. Optoelectronic device comprising a transfer substrate (250) and a plurality of elementary chips (232) bonded and electrically connected to the transfer substrate (250), each elementary chip (232) comprising a stack comprising, in the order from the upper surface of the transfer substrate (250), an integrated control circuit (151) formed inside and on top of a semiconductor substrate, a photodetection stage (201) comprising at least one photosensitive diode (171), and an emission stage (203) comprising at least one light-emitting diode (161).

20. Device according to claim 19, wherein, in each elementary chip, the photodetection stage (201) is arranged between the integrated control circuit (151) and the emission stage (203), and wherein said at least one photosensitive diode (171) has a semiconductor anode layer (103a) arranged on the side of the emission stage (203) and a semiconductor cathode layer (103c) arranged on the side of the integrated control circuit (151).

21. System comprising an optoelectronic device (300) realized by a method according to any of claims 1 to 18, the optoelectronic device (300) an active photosensitive diode stack (103) transferred on an integrated control circuit (151) formed in and on a semiconductor substrate, and an active an active light-emitting diode stack (113) transferred on the active photosensitive diode stack (103), the system comprising a light source adapted to emitting a light radiation in the wavelength range of sensitivity of the active photosensitive diode stack (103), preferably an infrared radiation.

22. System according to claim 21, wherein the light source is a remote source (310).

23. System according to claim 21, wherein the light source is integrated to the optoelectronic device (300) and comprises at least one light-emitting diode (161(b)) formed in the active light-emitting diode stack (113).