Up-conversion imaging device and up-conversion imaging method

Abstract

The invention discloses an up-conversion imaging device and an up-conversion imaging method, and belongs to the technical field of semiconductor imaging. The up-conversion imaging device comprises an up-conversion device and an imaging device connected with the up-conversion device; a microsphere structure is arranged on the surface of one side, close to the imaging device, of the up-conversion device; the surface of the microsphere structure is used as a light-emitting surface; an up-conversion device for converting the first image signal into a second image signal and emitting the second image signal from the light emitting surface; the wavelength of the first image signal is greater than that of the second image signal; and the imaging device is used for detecting a second image signal emitted by the light-emitting surface and carrying out image reproduction according to the second image signal. The detection efficiency of one end of the up-conversion device and the luminous efficiency of the other end of the up-conversion device can be improved at the same time, and the overall up-conversion efficiency of the up-conversion device is improved, so that the integration time of an imaging device can be shortened, the up-conversion imaging rate is improved, and the up-conversion imaging performance is improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor imaging technology, and in particular to an upconversion imaging device and an upconversion imaging method. Background Art

[0002] Traditional infrared focal plane imaging devices currently cover almost the entire infrared band from near infrared to far infrared. High-performance infrared imaging devices generally require cooling, and the longer the wavelength, the lower the operating temperature of the infrared imaging device. Repeated heating and cooling may cause pixel failure. Therefore, traditional infrared imaging devices currently face the problems of high cost, low yield, and high risk of low-temperature failure. Semiconductor upconversion imaging devices can solve the problem of low-temperature readout circuit failure and have more advantages in large-format imaging. However, existing upconversion imaging devices face the problems of low upconversion efficiency and long integration time, which leads to slow imaging speed. Summary of the invention

[0003] The purpose of the present application is to provide an upconversion imaging device and an upconversion imaging method. Based on the surface microsphere structure, the detection efficiency at one end of the upconversion device and the luminous efficiency at the other end can be improved simultaneously, thereby achieving an improvement in the overall upconversion efficiency of the upconversion device, thereby shortening the integration time of the imaging device, improving the upconversion imaging rate, and further improving the upconversion imaging performance.

[0004] To achieve the above-mentioned object, the present application provides an up-conversion imaging device, comprising: an up-conversion device and an imaging device connected to the up-conversion device; a microsphere structure is arranged on a surface of one side of the up-conversion device close to the imaging device; a surface of the microsphere structure serves as a light-emitting surface;

[0005] The up-conversion device is used to convert the first image signal into a second image signal, and emit the second image signal from the light-emitting surface; the wavelength of the first image signal is greater than the wavelength of the second image signal;

[0006] The imaging device is used to detect the second image signal emitted by the light-emitting surface and reproduce an image according to the second image signal.

[0007] Optionally, the light emitting surface of the up-conversion device and the light receiving surface of the imaging device are bonded and connected;

[0008] Or, the light emitting surface of the up-conversion device and the light receiving surface of the imaging device are bonded and connected by optical adhesive;

[0009] Alternatively, the light emitting surface of the up-conversion device and the light receiving surface of the imaging device are connected via an optical fiber.

[0010] Optionally, the up-conversion device is an infrared up-conversion device; the first image signal is an infrared image signal; and the second image signal is a near-infrared image signal or a visible light image signal.

[0011] Optionally, the infrared up-conversion device includes an infrared detector and a light-emitting diode connected to the infrared detector; the microsphere structure is disposed on a surface of the light-emitting diode on a side facing away from the infrared detector;

[0012] The infrared detector is used to receive and detect infrared photons, convert the infrared photons into photoelectrons, and make the photoelectrons migrate to the activation area of ​​the light-emitting diode under the action of the electric field;

[0013] The light emitting diode is used for combining the photoelectrons migrated to the active region with the holes in the active region to generate near-infrared photons or visible light photons, and emitting the near-infrared photons or the visible light photons from the light emitting surface.

[0014] Optionally, the infrared detector is a semiconductor quantum well infrared detector, a mercury cadmium telluride infrared detector, an indium antimonide detector, an indium gallium arsenide detector, or an InAs / GaSb type II superlattice detector;

[0015] And / or, the light emitting diode is a GaAs-based light emitting diode or a GaN-based light emitting diode.

[0016] Optionally, a metal layer is provided on a surface of one side of the microsphere structure close to the imaging device, and the surface of the metal layer serves as the light-emitting surface; the metal layer is reflective to the infrared photons and transparent to the near-infrared photons or the visible light photons.

[0017] Optionally, the microsphere structure has a preset size and is arranged according to a preset period, so that the infrared photons are arranged in a preset manner inside the infrared detector.

[0018] Optionally, the imaging device is a silicon-based imaging device; the silicon-based imaging device is a silicon-based CCD device or a silicon-based CMOS device.

[0019] To achieve the above object, the present application also provides an up-conversion imaging method, comprising:

[0020] The first image signal is converted into a second image signal by an up-conversion device, and the second image signal is emitted from a light-emitting surface of the up-conversion device; a microsphere structure is arranged on a surface of a side of the up-conversion device close to the imaging device; the surface of the microsphere structure serves as the light-emitting surface; the wavelength of the first image signal is greater than the wavelength of the second image signal;

[0021] The second image signal emitted by the light-emitting surface is detected by an imaging device connected to the up-conversion device, and image reproduction is performed according to the second image signal.

[0022] Obviously, the upconversion imaging device provided by the present application adds a microsphere structure to the light-emitting surface of the upconversion device, which can greatly reduce the total reflection limitation of the light emission inside the upconversion device and greatly improve the luminous efficiency of the upconversion device on the one hand; on the other hand, the appropriately designed surface microsphere structure can also change the light field distribution inside the upconversion device and enhance the detection efficiency of the upconversion device. By simultaneously improving the detection efficiency at one end of the upconversion device and the luminous efficiency at the other end, the overall upconversion efficiency of the upconversion device can be improved, thereby shortening the integration time of the imaging device, increasing the upconversion imaging rate, and thus improving the upconversion imaging performance. Compared with the prior art, it has the following advantages:

[0023] 1. Compared with traditional up-conversion imaging devices, this application has higher up-conversion efficiency, the integration time of the imaging device is greatly shortened, and the imaging speed is greatly improved;

[0024] 2. Compared with the traditional infrared focal plane imaging device, the large-scale conversion imaging device based on the surface microsphere structure enhancement of the present invention does not need to prepare separate pixels or readout circuits, which can greatly reduce the difficulty and cost of device preparation and integration.

[0025] The present application also provides an up-conversion imaging method having the above-mentioned beneficial effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0027] Figure 1 A schematic structural diagram of a first up-conversion imaging device provided in an embodiment of the present application;

[0028] Figure 2 A schematic structural diagram of a second up-conversion imaging device provided in an embodiment of the present application;

[0029] Figure 3 A schematic diagram of the structure of an up-conversion device provided in an embodiment of the present application;

[0030] Figure 4 A flowchart of an up-conversion imaging method provided in an embodiment of the present application;

[0031] Figure 5 A flow chart of a method for preparing an upconversion imaging device provided in an embodiment of the present application;

[0032] Figure 6 A schematic structural diagram of a third up-conversion imaging device provided in an embodiment of the present application.

[0033] The following are the descriptions of the reference numerals:

[0034] 1-upconversion device; 10-microsphere structure; 2-imaging device; 3-optical coupling structure; 11-infrared detector; 12-light-emitting diode; 111-QWIP detector; 121-GaAs-based light-emitting diode; 21-silicon-based CCD device; 31-optical fiber cluster. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0036] Infrared imaging technology has important application prospects in defense and military, civil security, biomedicine, anti-terrorism and explosion prevention, atmospheric remote sensing and other fields. The core device of existing infrared imaging technology is a two-dimensional infrared focal plane array, which integrates a large-scale array pixel unit detector and places the photosensitive chip on the focal plane of the optical system to directly obtain a two-dimensional infrared image. The infrared focal plane array is usually interconnected with the silicon-based readout circuit through flip-chip interconnection technology to complete the process of optical signal acquisition and electrical signal readout. Generally speaking, the detector focal plane array and the silicon-based signal readout circuit are grown and prepared based on different semiconductor material systems, and then the two are heterogeneously integrated. Each unit in the detector array is connected to the readout circuit through an electrically connected metal (usually an indium column). The flip-chip integrated infrared focal plane imaging array has a complex structure, high technical difficulty, high cost and low yield. Semiconductor up-conversion pixel-free infrared imaging is an indirect infrared imaging technology that replaces the traditional focal plane. Its working principle is: infrared signals and images are first converted into near-infrared signals or images by up-conversion devices, and then indirect imaging is achieved by mature commercial silicon-based imaging devices. The core device is a semiconductor up-conversion device, and its microscopic working mechanism is: the incident low-energy infrared photons are first absorbed in the infrared detector part to generate photoelectrons. The carriers gain energy under the action of the electric field and migrate to the active layer area of ​​the light-emitting diode with a wider band gap. Finally, radiative recombination occurs in the active layer to release high-energy near-infrared photons, thereby achieving up-conversion. However, the up-conversion efficiency of existing up-conversion devices is too low, resulting in a long time integral of infrared imaging, which seriously affects the up-conversion imaging efficiency.

[0037] Therefore, the present application provides an upconversion imaging device, which, based on the coupling of the surface microsphere structure, greatly reduces the total reflection limitation of the light emission inside the upconversion device, and greatly improves the luminous efficiency of the upconversion device; and the appropriately designed surface microsphere structure can also change the light field distribution inside the upconversion device, and simultaneously enhance the detection efficiency of the upconversion device, thereby improving the overall upconversion efficiency of the upconversion device, greatly reducing the integration time of the imaging device, and significantly improving the imaging speed of the upconversion imaging device, which has important practical value.

[0038] Please refer to Figures 1 to 3 An upconversion imaging device provided in an embodiment of the present application may include: an upconversion device 1 and an imaging device 2 connected to the upconversion device 1; a microsphere structure 10 is provided on a surface of the upconversion device 1 close to the imaging device 2; and a surface of the microsphere structure 10 serves as a light-emitting surface;

[0039] An up-conversion device 1, used for converting a first image signal into a second image signal, and emitting the second image signal from a light-emitting surface; the wavelength of the first image signal is greater than the wavelength of the second image signal;

[0040] The imaging device 2 is used to detect the second image signal emitted by the light-emitting surface and reproduce the image according to the second image signal.

[0041] It should be noted that the first image signal in this embodiment is a photon reflected by the object to be measured, and the second image signal is a photon with a wavelength smaller than the photon obtained by converting the photon reflected by the object to be measured. The first image signal may be, but is not limited to, an infrared image signal; the second image signal may be, but is not limited to, a near-infrared image signal or a visible light image signal. The infrared image signal may be, but is not limited to, an infrared two-dimensional image signal; the near-infrared image signal may be, but is not limited to, a near-infrared two-dimensional image signal; and the visible light image signal may be, but is not limited to, a visible light two-dimensional image signal.

[0042] This embodiment does not limit the specific connection method between the up-conversion device 1 and the imaging device 2, as long as the up-conversion device 1 and the imaging device 2 can be optically interconnected, for example:

[0043] Can be used Figure 1 The direct optical coupling method shown is as follows: the light emitting surface of the up-conversion device 1 and the light receiving surface of the imaging device 2 can be bonded; or, the light emitting surface of the up-conversion device 1 and the light receiving surface of the imaging device 2 can be bonded and connected by optical adhesive;

[0044] You can also use Figure 2 In the indirect optical coupling method shown by the optical coupling structure 3, the light emitting surface of the upconverter device 1 and the light receiving surface of the imaging device 2 can be connected by optical fiber. This embodiment does not limit the specific number of optical fibers, which can be a single optical fiber or an optical fiber cluster 31.

[0045] This embodiment does not limit the specific type of the up-conversion device 1. For example, the up-conversion device 1 may be an infrared up-conversion device 1; the first image signal is an infrared image signal; and the second image signal is a near-infrared image signal or a visible light image signal.

[0046] This embodiment does not limit the specific structure of the infrared conversion device, as long as it can achieve the conversion of the infrared image signal into a near-infrared image signal or a visible light image signal, for example Figure 3 The infrared up-conversion device 1 shown may include an infrared detector 11 and a light emitting diode 12 connected to the infrared detector 11; a microsphere structure 10 is disposed on a surface of the light emitting diode 12 facing away from the infrared detector 11;

[0047] The infrared detector 11 is used to receive and detect infrared photons, convert the infrared photons into photoelectrons, and make the photoelectrons migrate to the activation area of ​​the light-emitting diode 12 under the action of the electric field;

[0048] The light emitting diode 12 is used to recombine the photoelectrons migrated to the active region with the holes in the active region to generate near-infrared photons or visible light photons, and emit the near-infrared photons or visible light photons from the light emitting surface; the near-infrared photons may be near-infrared photons with a wavelength less than 1 micron;

[0049] This embodiment does not limit the specific type of the infrared detector 11. For example, the infrared detector 11 can be a semiconductor quantum well infrared detector (Quantum Well Infrared Photodetector, QWIP), a mercury cadmium telluride (HgCdTe) infrared detector, an indium antimonide (InSb) detector, an indium gallium arsenide (InGaAs) detector, or an InAs / GaSb type II superlattice detector.

[0050] The present embodiment does not limit the specific type of the light emitting diode 12 . For example, the light emitting diode 12 may be a GaAs-based light emitting diode or a GaN-based light emitting diode.

[0051] Furthermore, in this embodiment, a metal layer may be provided on the surface of one side of the microsphere structure 10 close to the imaging device 2, and the surface of the metal layer serves as a light-emitting surface; the metal layer is reflective to infrared photons and transparent to near-infrared photons or visible light photons. It should be noted that in this embodiment, by adding a metal layer to the light-emitting surface of the up-conversion device 1, the reflectivity of infrared photons can be increased, and the infrared photons can be reflected back into the infrared detector 11, thereby improving the detection efficiency of the infrared detector 11.

[0052] Furthermore, in this embodiment, the microsphere structure 10 may have a preset size and be arranged according to a preset period, so that the infrared photons are arranged according to a preset manner inside the infrared detector 11. It should be noted that in this embodiment, by adjusting the size and periodic arrangement of the microsphere structure 10, the light field arrangement inside the infrared detector 11 can be adjusted to enhance the light field intensity inside the infrared detector 11, thereby improving the detection efficiency of the infrared detector 11.

[0053] Furthermore, in this embodiment, a sapphire sheet may be provided on the surface of the microsphere structure 10 close to the imaging device 2. It should be noted that the sapphire sheet added in this embodiment can provide support for the microsphere structure 10, improve structural stability, and thus facilitate packaging.

[0054] This embodiment does not limit the specific type of the imaging device 2. For example, the imaging device 2 may be a silicon-based imaging device; the silicon-based imaging device may be a silicon-based CCD (Charge Coupled Device) device or a silicon-based CMOS (Complementary Metal-Oxide-Semiconductor) device.

[0055] Based on the above embodiments, the present application adds a microsphere structure to the light-emitting surface of the up-conversion device. On the one hand, it can greatly reduce the total reflection limitation of the light emission inside the up-conversion device and greatly improve the luminous efficiency of the up-conversion device. On the other hand, the appropriately designed surface microsphere structure can also change the light field distribution inside the up-conversion device and enhance the detection efficiency of the up-conversion device. By simultaneously improving the detection efficiency at one end of the up-conversion device and the luminous efficiency at the other end, the overall up-conversion efficiency of the up-conversion device can be improved, thereby shortening the integration time of the imaging device, improving the up-conversion imaging rate, and thus improving the up-conversion imaging performance. Compared with the prior art, it has the following advantages:

[0056] 1. Compared with traditional up-conversion imaging devices, this application has higher up-conversion efficiency, the integration time of the imaging device is greatly shortened, and the imaging speed is greatly improved;

[0057] 2. Compared with the traditional infrared focal plane imaging device, the large-scale conversion imaging device based on the surface microsphere structure enhancement of the present invention does not need to prepare separate pixels or readout circuits, which can greatly reduce the difficulty and cost of device preparation and integration.

[0058] Please refer to Figure 4 , Figure 4 A flowchart of an up-conversion imaging method provided in an embodiment of the present application, the method may include:

[0059] S101: Convert a first image signal into a second image signal through an up-conversion device, and emit the second image signal from the light-emitting surface of the up-conversion device; a microsphere structure is provided on a surface of the up-conversion device close to the imaging device; the surface of the microsphere structure serves as a light-emitting surface, and the wavelength of the first image signal is greater than the wavelength of the second image signal.

[0060] This embodiment does not limit the specific manner of converting the first image signal into the second image signal. The specific conversion manner of the up-conversion device may be determined according to the specific structure of the up-conversion device. For example, when the infrared up-conversion device includes an infrared detector and a light-emitting diode connected to the infrared detector; and a microsphere structure is disposed on a surface of the light-emitting diode facing away from the infrared detector, step S101 may include:

[0061] The infrared detector receives and detects infrared photons, converts them into photoelectrons, and causes the photoelectrons to migrate to the active area of ​​the light-emitting diode under the action of the electric field;

[0062] The photoelectrons that migrate to the active region are recombined with holes in the active region through the light-emitting diode to generate near-infrared photons or visible light photons.

[0063] S102: Detecting a second image signal emitted by the light-emitting surface through an imaging device connected to the up-conversion device, and performing image reproduction according to the second image signal.

[0064] Based on the above embodiments, the present application performs upconversion imaging based on the above upconversion imaging device, with higher upconversion efficiency, shorter integration time and faster imaging speed.

[0065] Please refer to Figure 5 , Figure 5 A flowchart of a method for preparing an upconversion imaging device provided in an embodiment of the present application, the method may include:

[0066] S201: Prepare an up-conversion device; a microsphere structure is provided on a surface of the up-conversion device close to the imaging device; the surface of the microsphere structure serves as a light-emitting surface; the up-conversion device is used to convert a first image signal into a second image signal, and emit the second image signal from the light-emitting surface; the wavelength of the first image signal is greater than the wavelength of the second image signal.

[0067] This embodiment does not limit the specific method of preparing the up-conversion device. For example, step S201 may include:

[0068] Providing an epitaxial wafer and preparing an electrode on the front side of the epitaxial wafer;

[0069] After the electrode is prepared, a microsphere structure is prepared on the front side of the epitaxial wafer;

[0070] After the microsphere structure is prepared, the back side of the epitaxial wafer is etched to expose the electrode to obtain an up-conversion device.

[0071] This embodiment does not limit the specific method of preparing the microsphere structure, for example:

[0072] The PS ball (Polystyrene) mask method can be used for preparation: the epitaxial wafer is cleaned; after cleaning, the epitaxial wafer is preheated; after preheating, the front side of the epitaxial wafer is evenly coated with glue and exposed to ultraviolet light to protect the non-window area; after exposure, a layer of PS balls is laid on the front side of the epitaxial wafer, and the balls are evenly distributed in the window area; after the PS balls are laid, dry etching is performed using the PS balls as a mask; after etching, the glue is stripped.

[0073] It can also be prepared by etching using a photoresist pattern transfer method.

[0074] Furthermore, in order to arrange the infrared photons in a preset manner inside the infrared detector, in this embodiment, a microsphere structure having a preset size and arranged in a preset period is prepared on the front side of the epitaxial wafer.

[0075] Furthermore, in order to improve the detection efficiency of the up-conversion device, the present embodiment can also set a metal layer on the surface of the side of the microsphere structure close to the imaging device. The present embodiment does not limit the specific method of setting the metal layer, for example, the epitaxial wafer can be cleaned and blown dry; after blowing dry, the epitaxial wafer is preheated; after the preheating is completed, the front of the epitaxial wafer is coated with glue and ultraviolet exposure is performed; after the exposure is completed, glue is applied to ensure adhesion; after the glue is applied, metal sputtering is performed to form a metal layer on the surface of the side of the microsphere structure close to the imaging device; after the metal layer is prepared, a peeling operation is performed.

[0076] Furthermore, in order to improve the structural stability, the present embodiment may also arrange a sapphire sheet on the surface of the microsphere structure close to the imaging device. The present embodiment does not limit the specific method of arranging the sapphire sheet, for example, the sapphire sheet may be cleaned and dried; after drying, the sapphire sheet may be diced to a suitable size; after dicing, the sapphire sheet may be glued, and after glueing, bonding may be performed using an ultraviolet curing lamp.

[0077] Furthermore, in order to improve the transmittance of the first image signal, the present embodiment may also thin the back side of the epitaxial wafer. The present embodiment does not limit the specific method of thinning the back side of the epitaxial wafer, because thinning the back side of the epitaxial wafer is actually thinning the substrate part of the epitaxial wafer, so the corresponding thinning method may be selected according to the specific type of the substrate.

[0078] This embodiment does not limit the specific type and structure of the up-conversion device. You may refer to the above-mentioned embodiment of the up-conversion imaging device, which will not be described in detail here.

[0079] It should be noted that the up-conversion device in this embodiment mainly adopts semiconductor III-V materials, and its epitaxial wafer can be directly grown on a semiconductor substrate using metal oxide chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE), and then prepared using standard semiconductor technical means such as lithography and engraving. The process is standard, which is conducive to mass and low-cost production.

[0080] S202: Connect the up-conversion device and the imaging device to detect the second image signal emitted by the light-emitting surface through the imaging device, and reproduce the image according to the second image signal.

[0081] It should be noted that, in this embodiment, the conversion device and the imaging device need to be integrated together into a whole, so that the second image signal obtained by up-conversion of the up-conversion device can be coupled into the imaging device. The specific integration method may include:

[0082] (1) grinding the light-emitting surface of the up-conversion device and the light-receiving surface of the imaging device; after the grinding is completed, bonding the light-emitting surface of the up-conversion device and the light-receiving surface of the imaging device together by wafer bonding technology;

[0083] (2) grinding the light-emitting surface of the up-conversion device and the light-receiving surface of the imaging device; after grinding, pressing the up-conversion device and the imaging device together with only a micrometer-sized gap in between; filling the gap with optical glue and bonding them with the optical glue;

[0084] (3) Connect an optical fiber between the light-emitting surface of the up-conversion device and the light-receiving surface of the imaging device, and use optical fiber coupling for light transmission.

[0085] Based on the above embodiments, the upconversion imaging device prepared by the present application is used to perform upconversion imaging, which has higher upconversion efficiency, shorter integration time and faster imaging speed.

[0086] The following is a specific example to illustrate the preparation process of the above up-conversion imaging device. Please refer to Figure 6 , Figure 6 An example of an infrared up-conversion device of the present application is shown, wherein the infrared detector 11 in the up-conversion device 1 adopts a QWIP detector 111, the light-emitting diode 12 adopts a GaAs-based light-emitting diode 121 with a double heterojunction structure, the coupling method adopts an optical fiber cluster 31 coupling, and the silicon-based imaging device adopts a silicon-based CCD device 21. The specific method for preparing the up-conversion imaging device is as follows:

[0087] 1. Preparation: Provide epitaxial wafers and slice them into appropriate sizes;

[0088] 2. Mesa etching:

[0089] The epitaxial wafers were cleaned and dried: 5% Decon 90, deionized water, deionized water, acetone, ethanol, and deionized water were used for cleaning at 300W megasonics for 5 minutes, followed by deionized water rinse for more than 10 seconds and drying with an N2 gun; Decon 90 is a leading surfactant cleaner and radioactive decontaminant;

[0090] After cleaning and drying, the epitaxial wafer is dry-etched to obtain the electrode area to be set: the epitaxial wafer is coated (using AZ5214 photoresist, which is a high-resolution pattern inversion positive / negative changeable photoresist), and preheated with a hot plate at 110 ° C for at least 5 minutes; after preheating, AZ5214 photoresist is coated at 4000rpm, 60s and 110 ° C for 70s, and a plasma stripper is used to coat to ensure adhesion; after coating, the hot plate is set at 120 ° C for 2 minutes; after coating, in an ICP (Inductively Coupled Plasma) device, pure silicon carrier, without oil, set the parameters to Cl2=10sccm, BCl3=10sccm, ICP=0W, RF (radio frequency)=50W, pressure is 1mTorr, temperature is 20°C, voltage is 260V, The etching rate is 160nm / min, and the dry etching takes about 12min. After the dry etching is completed, the resist removal operation is performed;

[0091] 3. Ohmic contact:

[0092] Clean and dry the epitaxial wafer;

[0093] After cleaning and drying, a metal layer is prepared in the electrode area of ​​the epitaxial wafer: the epitaxial wafer is preheated to 150°C for at least 5 minutes; after preheating, LOR10A photoresist (a material based on polydimethylglutarimide (PMGI) polymer) is used at 4000rpm for 60s and heated at 150°C for 3 minutes; after heating, AZ5214 photoresist is heated at 4000rpm, 60s and 110°C for 70s for coating; the coating result is exposed to ultraviolet light and developed; after development, a plasma stripper is used to apply glue to ensure adhesion; after coating, the excess photoresist is rinsed and dried; metal is evaporated on the rinsed epitaxial wafer using electron beam evaporation technology to form a metal layer in the electrode area; after the metal layer is prepared, a stripping operation is performed and it is washed and dried;

[0094] 4. Annealing: Anneal the epitaxial wafer at 380°C to form an ohmic contact;

[0095] 5. Electroplating electrode:

[0096] Cleaning the epitaxial wafer;

[0097] After cleaning, electroplate electrodes on the metal layer surface of the epitaxial wafer: preheat the epitaxial wafer at 110°C for 5 minutes; after preheating, use AZ5214 photoresist to coat the epitaxial wafer, and perform UV exposure and development; after development, use a plasma degumming machine to coat for 1 minute to ensure adhesion; after coating, use a hot plate to heat at 120°C for 2 minutes to harden the film; after hardening, use an independent target chamber magnetron sputtering to sputter Ti and Au materials; after sputtering, coat and UV exposure, coat, and electroplate electrodes; after electrode preparation, degumming is performed in sequence, the seed layer is etched, and the etching degree is detected and determined, and then degumming is performed and rinsed and dried;

[0098] 6. Preparation of surface microsphere structure 10:

[0099] The epitaxial wafer is cleaned; after cleaning, the epitaxial wafer is preheated at 150 °C for 5 minutes; after preheating, the epitaxial wafer is coated and exposed to UV light; after exposure, a layer of PS beads with a diameter of 1 μm is laid on the surface of the epitaxial wafer, and the beads are evenly distributed in the window area; after the PS beads are laid, dry etching is performed using the PS beads as a mask for about 20 minutes; after etching, a stripping operation is performed;

[0100] 7. Surface microsphere structure 10 coating: The epitaxial wafer is cleaned with acetone, ethanol and deionized water in turn under 300W megasonic conditions and blown dry with an N2 gun; after drying, the epitaxial wafer is preheated for at least 5 minutes; after preheating, the epitaxial wafer is coated with glue and exposed to ultraviolet light; after exposure, glue is applied to ensure adhesion; after glue application, metal sputtering is performed to obtain a metal layer; after the metal layer is prepared, it is peeled off;

[0101] 8. Flip-chip bonding: Clean and dry the sapphire sheet; after drying, cut the sapphire sheet into appropriate sizes; after cutting, apply glue to the sapphire sheet, and after applying glue, use a UV curing lamp to bond for 60 seconds;

[0102] 9. Thinning: Use wet selective chronic etching of GaAs substrate and wet etching of AlGaAs substrate to thin the substrate to less than 50μm;

[0103] 10. Back contact: Clean the epitaxial wafer, apply the resist and perform UV exposure. After exposure, harden the film on a hot plate at 150°C for 2 minutes. After hardening, dry etch the epitaxial wafer until the upper electrode metal is exposed and over-etch for 10 seconds. After etching, remove the resist.

[0104] 11. After the epitaxial wafer is packaged, diced, bonded and wired, the up-conversion device 1 is processed;

[0105] 12. The light emitting surface of the up-conversion device is processed and coupled and integrated with the photosensitive surface (i.e., light receiving surface) of the silicon-based imaging device 2 by using an optical fiber cluster 31, so as to complete the optical connection from the up-conversion device 1 to the silicon-based imaging device, thereby realizing the integration of the up-conversion imaging device.

[0106] Specific examples are used herein to illustrate the principles and implementation methods of the present application, and the embodiments are in a progressive relationship, each embodiment focuses on the differences from other embodiments, and the same and similar parts between the embodiments can be referred to each other. The description of the above embodiments is only used to help understand the method and core ideas of the present application. For ordinary technicians in this technical field, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the claims of the present application.

[0107] It should also be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or equipment including the elements.

Claims

1. An upconversion imaging device, characterized in that: include: An up-conversion device and an imaging device connected to the up-conversion device; a microsphere structure is arranged on a surface of the up-conversion device close to the imaging device; a surface of the microsphere structure serves as a light-emitting surface; The up-conversion device is used to convert the first image signal into a second image signal, and emit the second image signal from the light-emitting surface; the wavelength of the first image signal is greater than the wavelength of the second image signal; The imaging device is used to detect the second image signal emitted by the light-emitting surface and reproduce an image according to the second image signal.

2. The up-conversion imaging device according to claim 1, characterized in that: The light emitting surface of the up-conversion device and the light receiving surface of the imaging device are bonded and connected; Or, the light emitting surface of the up-conversion device and the light receiving surface of the imaging device are bonded and connected by optical adhesive; Alternatively, the light emitting surface of the up-conversion device and the light receiving surface of the imaging device are connected via an optical fiber.

3. The up-conversion imaging device according to claim 1, characterized in that: The up-conversion device is an infrared up-conversion device; the first image signal is an infrared image signal; and the second image signal is a near-infrared image signal or a visible light image signal.

4. The up-conversion imaging device according to claim 3, characterized in that: The infrared up-conversion device comprises an infrared detector and a light-emitting diode connected to the infrared detector; the microsphere structure is arranged on a surface of the light-emitting diode facing away from the infrared detector; The infrared detector is used to receive and detect infrared photons, convert the infrared photons into photoelectrons, and make the photoelectrons migrate to the activation area of ​​the light-emitting diode under the action of the electric field; The light emitting diode is used for combining the photoelectrons migrated to the active region with the holes in the active region to generate near-infrared photons or visible light photons, and emitting the near-infrared photons or the visible light photons from the light emitting surface.

5. The up-conversion imaging device according to claim 4, characterized in that: The infrared detector is a semiconductor quantum well infrared detector, a mercury cadmium telluride infrared detector, an indium antimonide detector, an indium gallium arsenide detector, or an InAs / GaSb type II superlattice detector; And / or, the light emitting diode is a GaAs-based light emitting diode or a GaN-based light emitting diode.

6. The up-conversion imaging device according to claim 4, characterized in that: A metal layer is arranged on the surface of one side of the microsphere structure close to the imaging device, and the surface of the metal layer serves as the light-emitting surface; the metal layer is reflective to the infrared photons and transparent to the near-infrared photons or the visible light photons.

7. The up-conversion imaging device according to claim 4, characterized in that: The microsphere structure has a preset size and is arranged according to a preset period, so that the infrared photons are arranged in a preset manner inside the infrared detector.

8. The up-conversion imaging device according to claim 1, characterized in that: The imaging device is a silicon-based imaging device; the silicon-based imaging device is a silicon-based CCD device or a silicon-based CMOS device.

9. An up-conversion imaging method, characterized in that: include: The first image signal is converted into a second image signal by an up-conversion device, and the second image signal is emitted from a light-emitting surface of the up-conversion device; a microsphere structure is arranged on a surface of a side of the up-conversion device close to the imaging device; the surface of the microsphere structure serves as the light-emitting surface; the wavelength of the first image signal is greater than the wavelength of the second image signal; The second image signal emitted by the light-emitting surface is detected by an imaging device connected to the up-conversion device, and image reproduction is performed according to the second image signal.

Images