Infrared light guide detector without metal reflecting layer on surface and preparation method of infrared light guide detector
By preparing a metal electrode area on the back of the photoelectric response area of the infrared optical conductors, and retaining the cadmium and mercury materials on the surface of the cadmium cadmium mercury semiconductor, the problem of reflection of the metal layer reflection light in the traditional detector is solved. Essence
Patent Information
- Application Number
- CN202411516605.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-29
- Publication Date
- 2025-01-28
AI Technical Summary
In traditional infrared light guide detectors, the metal layer in the electrode interconnection region causes light to reflect, affecting the interference effect of the FTIR optical system.
Design an infrared optical guide detector with no metal reflective layer on the surface. The metal electrode area is prepared on the back of the photoelectric response area, and the cadmium mercury material is retained on the surface of the cadmium cadmium semiconductor surface to reduce the light reflection.
Effectively reduce the reflection of light on the surface of the detector, improve the interference effect of the FTIR instrument, and solve the problem of mixed gown caused by the strong reflection light on the electrode metal surface.
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Figure CN119384094A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of infrared photoelectric devices, in particular to an infrared photoconductive detector without a metal reflective layer on the surface and a preparation method thereof. Background Art
[0002] See also Figure 3 The traditional mercury cadmium telluride photoconductive detector is composed of a photoelectric response area 4 and an electrode interconnection area 3 located on a substrate 1. Among them, a back passivation layer 6 is also grown below the photoelectric response area 4. The back passivation layer 6 and the substrate 1 are fixedly connected by an epoxy glue 2. The photoelectric response area 4 and the electrode interconnection area 3 are both on the front side of the semiconductor, and a front passivation layer 7 is grown on the surface of the photoelectric response area 4. Due to the need for signal extraction, the electrode interconnection area 3 of the traditional photoconductive detector generally has a large area of metal layer, so more than 90% of the light reaching the electrode interconnection area 3 will be reflected by the metal. These reflected light rays are unexpected light rays in the optical imaging system, which will cause the optical system to generate stray light, thereby affecting the interference effect of the FTIR optical system. Even if the electrode interconnection area 3 is surface treated, such as blackening, the reflectivity of the metal layer will only decrease slightly, and the stray light problem of the electrode interconnection area 3 cannot be solved well. Summary of the invention
[0003] The purpose of the present invention is to provide an infrared photoconductive detector without a metal reflective layer on the surface and a preparation method thereof, mainly to solve the problems existing in the above-mentioned prior art.
[0004] In order to achieve the above-mentioned object, the technical solution adopted by the present invention is to provide an infrared photoconductive detector without a metal reflective layer on the surface, characterized in that it comprises a photoelectric response area, a non-photoelectric response area, an electrode interconnection area and a substrate;
[0005] Above the photoelectric response area is the front light detection area; the photoelectric response area and the non-photoelectric response area are arranged at intervals; below the photoelectric response area and the non-photoelectric response area is the electrode interconnection area located on the back side; the electrode interconnection area includes a positive electrode area and a negative electrode area; the back side of the photoelectric response area is connected to the positive electrode area and the negative electrode area at the same time, and the carriers generated by the photoelectric effect in the photoelectric response area enter or leave through the positive electrode area or the negative electrode area; the back side of the non-photoelectric response area is connected to one of the positive electrode area and the negative electrode area; and below the electrode interconnection area is the substrate.
[0006] Furthermore, the photoelectric response area includes a first front passivation layer and a first semiconductor layer; the back side of the first semiconductor layer is connected to the positive electrode area and the negative electrode area at the same time; and above the first semiconductor layer, a layer of the first front passivation layer for protecting the first semiconductor layer is covered.
[0007] Furthermore, the non-photoelectric response area includes a second front passivation layer and a second semiconductor layer; the back side of the second semiconductor layer is connected to one of the positive electrode area or the negative electrode area; and above the second semiconductor layer, a layer of the second front passivation layer for protecting the second semiconductor layer is covered.
[0008] Furthermore, the thickness of the first semiconductor layer and the second semiconductor layer is preferably 10 micrometers.
[0009] Further, the electrode interconnection region includes the positive electrode region, the negative electrode region and the insulating region;
[0010] The insulating region is located between the positive electrode region and the negative electrode region, and is used to form electrical insulation between the positive electrode region and the negative electrode region; the metal electrodes of the positive electrode region and the negative electrode region are composed of an indium metal layer and a gold metal layer; the indium metal layer is bonded to the photoelectric response region or the non-photoelectric response region; and the gold metal layer is bonded to the substrate.
[0011] Furthermore, the thickness of the indium metal layer is preferably 20 nanometers; the thickness of the gold metal layer is preferably 300 nanometers.
[0012] Furthermore, the substrate and the electrode interconnection area are connected and fixed by epoxy glue.
[0013] The present invention also discloses a method for manufacturing the above-mentioned infrared photoconductive detector without a metal reflective layer on the surface, characterized in that it comprises the steps of:
[0014] Step S100, forming the electrode interconnection region on the back side of the mercury cadmium telluride semiconductor;
[0015] Step S200, attaching the substrate to the electrode interconnection region using epoxy glue;
[0016] Step S300, performing a thinning, polishing and etching process on the front surface of the mercury cadmium telluride semiconductor;
[0017] Step S400: generating the photoelectric response region and the non-photoelectric response region on the front surface of the mercury cadmium telluride semiconductor.
[0018] Furthermore, in step S100, the steps are specifically included:
[0019] Step S101, growing a mercury cadmium telluride oxide layer on the back side of the mercury cadmium telluride semiconductor by an electrochemical method;
[0020] Step S102, using a photolithography and etching method to remove a portion of the mercury cadmium telluride oxide layer on the mercury cadmium telluride oxide layer, so that the shape of the remaining mercury cadmium telluride oxide layer is consistent with that of the insulating region;
[0021] Step S103, by ion sputtering, in the area not protected by the mercury cadmium telluride oxide layer, an indium metal layer and a gold metal layer are sequentially formed as the positive electrode region and the negative electrode region; the retained mercury cadmium telluride oxide layer forms the insulating region.
[0022] Furthermore, step S400 specifically includes the following steps:
[0023] Step S401, growing a mercury cadmium telluride oxide layer on the front surface of the mercury cadmium telluride semiconductor by an electrochemical method;
[0024] Step S402, using front and back alignment photolithography, forming the photoelectric response area on the front side of the mercury cadmium telluride semiconductor, corresponding to the positive electrode area and the negative electrode area; the remaining area forms the non-photoelectric response area;
[0025] Step S403, growing a mercury cadmium telluride oxide layer on the front surface of the mercury cadmium telluride semiconductor by an electrochemical method, and photolithography a separation area between the photoelectric response area and the non-photoelectric response area;
[0026] Step S404, using an etching process to remove the mercury cadmium telluride semiconductor between the photoelectric response region and the non-photoelectric response region, thereby separating the photoelectric response region and the non-photoelectric response region; during the etching process, controlling the etching depth to retain the electrode interconnection region on the back side of the mercury cadmium telluride semiconductor.
[0027] In view of the above technical features, the infrared photoconductive detector without a metal reflective layer on the surface and the preparation method thereof of the present invention have the following significant advantages over the prior art:
[0028] 1. The present invention prepares a metal electrode region on the back of the photoelectric response region, and retains the mercury cadmium telluride material in the corresponding area on the front of the back metal electrode region, and utilizes the absorption of light by the mercury cadmium telluride material to reduce the light reflection of the non-photoelectric response region.
[0029] 2. In the present invention, since the metal electrode area is on the back and there is no metal layer on the surface of the mercury cadmium telluride semiconductor, the reflection of light on the detector surface is further reduced, solving the problem of the interference effect of the FT IR instrument affected by the strong reflected light on the metal surface of the electrode. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Figure 1 It is a schematic diagram of the side view structure of a preferred embodiment of the infrared photoconductive detector of the present invention having no metal reflective layer on the surface;
[0031] Figure 2 It is a method flow chart of a preferred embodiment of the method for manufacturing an infrared photoconductive detector having no metal reflective layer on the surface of the present invention;
[0032] Figure 3 It is a schematic diagram of the side view structure of an infrared photoconductive detector in the prior art.
[0033] In the figure: 1-substrate, 2-epoxy glue, 3-electrode interconnection area, 4-photoelectric response area, 5-non-photoelectric response area;
[0034] 31-positive electrode region, 32-negative electrode region, 33-insulating region;
[0035] 41-first front passivation layer, 42-first semiconductor layer;
[0036] 51 - second front passivation layer, 52 - second semiconductor layer. DETAILED DESCRIPTION
[0037] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.
[0038] See also Figure 1 The present invention discloses an infrared photoconductive detector without a metal reflective layer on the surface. A preferred embodiment thereof comprises a photoelectric response region 4, a non-photoelectric response region 5, an electrode interconnection region 3 and a substrate 1.
[0039] The photoelectric response region 4 and the non-photoelectric response region 5 are both formed by processing on the mercury cadmium telluride semiconductor, and they are located on the same horizontal plane. The photoelectric response region 4 and the non-photoelectric response region 5 are arranged alternately. Below the mercury cadmium telluride semiconductor, that is, on the back of the photoelectric response region 4 and the non-photoelectric response region 5, is the electrode interconnection region 3. Below the electrode interconnection region 3 is the substrate 1. The material of the substrate 1 is sapphire, and the substrate 1 and the electrode interconnection region 3 are bonded by epoxy glue 2.
[0040] The electrode interconnection area 3 includes a positive electrode area 31, a negative electrode area 32, and an insulating area 33. Among them, the positive electrode area 31 and the negative electrode area 32 are metal lines, which are composed of an indium metal layer and a gold metal layer grown by sputtering, and connect multiple photoelectric response areas 4 to each other from the back. The indium metal layer has a thickness of 20 nanometers and is attached to the photoelectric response area 4 or the non-photoelectric response area 5, while the gold metal layer has a thickness of 300 nanometers and is attached to the substrate 1. The material of the insulating area 33 is a mercury cadmium telluride passivation layer, which is located between the positive electrode area 31 and the negative electrode area 32, isolating the positive electrode area 31 and the negative electrode area 32 to form electrical insulation.
[0041] The photoelectric response region 4 includes two layers, a first front passivation layer 41 located on the front surface and a first semiconductor layer 42 located thereunder. The material of the first semiconductor layer 42 is a mercury cadmium telluride semiconductor with a thickness of 10 microns. The back of the first semiconductor layer 42 is connected to both the positive electrode region 31 and the negative electrode region 32. The photoelectric response region 4 generates a photoelectric effect. When light shines on the front of the photoelectric response region 4, photons pass through the first front passivation layer 41 and enter the first semiconductor layer 42, generating carriers due to the photoelectric effect. The generated carriers enter or leave the photoelectric response region 4 through the positive electrode region 31 or the negative electrode region 32, thereby forming a signal. The first front passivation layer 41 is a mercury cadmium telluride oxide layer generated on the surface of the mercury cadmium telluride semiconductor during the semiconductor process. It covers the surface of the first semiconductor layer and protects the mercury cadmium telluride semiconductor thereunder.
[0042] The non-photoelectric response area 5 includes two layers, a second front passivation layer 51 located on the front surface and a second semiconductor layer 52 located thereunder. The material of the second semiconductor layer 52 is a mercury cadmium telluride semiconductor with a thickness of 10 microns. The back of the second semiconductor layer 52 is either connected to the positive electrode area 31 or to the negative electrode area 32, but not to the positive electrode area 31 or to the negative electrode area 32 at the same time. The second front passivation layer 51 is a mercury cadmium telluride oxide layer generated on the surface of the mercury cadmium telluride semiconductor during the semiconductor process, which covers the surface of the second semiconductor layer 52 to protect the mercury cadmium telluride semiconductor thereunder. The non-photoelectric response area 5 has no response to light, but only absorbs the light incident on the surface to reduce stray light, and photons entering the non-photoelectric response area 5 do not generate signals.
[0043] See also Figure 2 The present invention also discloses a method for preparing the infrared photoconductive detector without a metal reflective layer on the surface. A preferred embodiment thereof comprises the steps of:
[0044] Step S1, growing a mercury cadmium telluride oxide layer on the back side of the mercury cadmium telluride semiconductor.
[0045] On the back side of the mercury cadmium telluride semiconductor, surface treatment is performed and a mercury cadmium telluride oxide layer is grown by an electrochemical method.
[0046] Step S2, forming an insulating region.
[0047] According to the shape of the insulating area, the surface of the mercury cadmium telluride oxide layer is photolithographically processed, and then the mercury cadmium telluride oxide layers in the positive electrode area and the negative electrode area are removed by photolithography and etching methods, and the mercury cadmium telluride oxide layer in the shape of the insulating area is retained.
[0048] Step S3, forming a positive electrode region and a negative electrode region.
[0049] On the back of the mercury cadmium telluride semiconductor, a 20-nanometer-thick indium metal layer and a 300-nanometer-thick gold metal layer were deposited by ion sputtering using a coating process.
[0050] After removing the excess metal on the surface, only the HgCdTe oxide layer is left in the area protected by the HgCdTe oxide layer, forming an insulating area. In the area not protected by the HgCdTe oxide layer, the indium metal layer and the gold metal layer are left, thus forming the metal lines of the positive and negative regions.
[0051] Step S4, connecting the substrate.
[0052] The substrate is adhered and fixed to the back side of the electrode interconnection area by using epoxy glue.
[0053] Step S5, thinning the HgCdTe semiconductor.
[0054] A thinning, polishing and etching process is performed on the front side of the mercury cadmium telluride semiconductor, so that the thickness of the mercury cadmium telluride semiconductor is reduced to 10 microns, forming a mercury cadmium telluride semiconductor slice.
[0055] Step S6, growing a mercury cadmium telluride oxide layer on the front side of the mercury cadmium telluride semiconductor.
[0056] On the front side of the mercury cadmium telluride semiconductor, surface treatment is performed to grow a mercury cadmium telluride oxide layer by an electrochemical method.
[0057] Step S7, locating the photoelectric response area.
[0058] By using the front and back alignment photolithography, the mercury cadmium telluride oxide layer on the front side of the mercury cadmium telluride semiconductor is positioned at positions corresponding to the positive electrode region and the negative electrode region as photoelectric response regions, and the mercury cadmium telluride oxide layer at positions corresponding to the positive electrode region and the negative electrode region is removed.
[0059] Step S8, locating the separation area.
[0060] On the front side of the HgCdTe semiconductor, a surface treatment is performed to grow a HgCdTe oxide layer by electrochemical methods, and then the separation area between the photoelectric response area and the non-photoelectric response area is photolithographically processed.
[0061] Step S9, forming a photoelectric response region and a non-photoelectric response region.
[0062] By using an etching process, the mercury cadmium telluride semiconductor material between the photoelectric response region and the non-photoelectric response region, i.e., the separation region, is removed from the front side of the mercury cadmium telluride semiconductor, thereby separating and isolating the photoelectric response region and the non-photoelectric response region. In the etching process, the etching depth is controlled to retain the electrode interconnection region located on the back side of the mercury cadmium telluride semiconductor.
[0063] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.
Claims
1. An infrared photoconductive detector without a metal reflective layer on the surface, characterized in that: It comprises a photoelectric response region, a non-photoelectric response region, an electrode interconnection region and a substrate; Above the photoelectric response area is the front light detection area; the photoelectric response area and the non-photoelectric response area are arranged at intervals; below the photoelectric response area and the non-photoelectric response area is the electrode interconnection area located on the back side; the electrode interconnection area includes a positive electrode area and a negative electrode area; the back side of the photoelectric response area is connected to the positive electrode area and the negative electrode area at the same time, and the carriers generated by the photoelectric effect in the photoelectric response area enter or leave through the positive electrode area or the negative electrode area; the back side of the non-photoelectric response area is connected to one of the positive electrode area and the negative electrode area; and below the electrode interconnection area is the substrate.
2. The infrared photoconductive detector without a metal reflective layer on the surface according to claim 1, characterized in that: The photoelectric response area includes a first front passivation layer and a first semiconductor layer; the back side of the first semiconductor layer is connected to the positive electrode area and the negative electrode area at the same time; and above the first semiconductor layer, a layer of the first front passivation layer for protecting the first semiconductor layer is covered.
3. The infrared photoconductive detector without a metal reflective layer on the surface according to claim 1, characterized in that: The non-photoelectric response area includes a second front passivation layer and a second semiconductor layer; the back side of the second semiconductor layer is connected to one of the positive electrode area or the negative electrode area; and above the second semiconductor layer, a layer of the second front passivation layer for protecting the second semiconductor layer is covered.
4. The infrared photoconductive detector without a metal reflective layer on the surface according to any one of claims 2 or 3, characterized in that: The thickness of the first semiconductor layer and the second semiconductor layer is preferably 10 micrometers.
5. The infrared photoconductive detector without a metal reflective layer on the surface according to claim 1, characterized in that: The electrode interconnection area includes the positive electrode area, the negative electrode area and the insulating area; The insulating region is located between the positive electrode region and the negative electrode region, and is used to form electrical insulation between the positive electrode region and the negative electrode region; the metal electrodes of the positive electrode region and the negative electrode region are composed of an indium metal layer and a gold metal layer; the indium metal layer is bonded to the photoelectric response region or the non-photoelectric response region; and the gold metal layer is bonded to the substrate.
6. The infrared photoconductive detector without a metal reflective layer on the surface according to claim 5, characterized in that: The thickness of the indium metal layer is preferably 20 nanometers; the thickness of the gold metal layer is preferably 300 nanometers.
7. The infrared photoconductive detector without a metal reflective layer on the surface according to claim 1, characterized in that: The substrate and the electrode interconnection area are connected and fixed by epoxy glue.
8. A method for manufacturing the infrared photoconductive detector without a metal reflective layer on the surface as claimed in claim 1, characterized in that: Contains steps: Step S100, forming the electrode interconnection region on the back side of the mercury cadmium telluride semiconductor; Step S200, attaching the substrate to the electrode interconnection region using epoxy glue; Step S300, performing a thinning, polishing and etching process on the front surface of the mercury cadmium telluride semiconductor; Step S400: generating the photoelectric response region and the non-photoelectric response region on the front surface of the mercury cadmium telluride semiconductor.
9. The method for preparing an infrared photoconductive detector having no metal reflective layer on the surface according to claim 8, characterized in that: In step S100, the steps are specifically included: Step S101, growing a mercury cadmium telluride oxide layer on the back side of the mercury cadmium telluride semiconductor by an electrochemical method; Step S102, using a photolithography and etching method to remove a portion of the mercury cadmium telluride oxide layer on the mercury cadmium telluride oxide layer, so that the shape of the remaining mercury cadmium telluride oxide layer is consistent with that of the insulating region; Step S103, by ion sputtering, in the area not protected by the mercury cadmium telluride oxide layer, an indium metal layer and a gold metal layer are sequentially formed as the positive electrode region and the negative electrode region; the retained mercury cadmium telluride oxide layer forms the insulating region.
10. The method for preparing an infrared photoconductive detector having no metal reflective layer on the surface according to claim 8, characterized in that: In step S400, the steps are specifically included: Step S401, growing a mercury cadmium telluride oxide layer on the front surface of the mercury cadmium telluride semiconductor by an electrochemical method; Step S402, using front and back alignment photolithography, forming the photoelectric response area on the front side of the mercury cadmium telluride semiconductor, corresponding to the positive electrode area and the negative electrode area; the remaining area forms the non-photoelectric response area; Step S403, growing a mercury cadmium telluride oxide layer on the front surface of the mercury cadmium telluride semiconductor by an electrochemical method, and photolithography a separation area between the photoelectric response area and the non-photoelectric response area; Step S404, using an etching process to remove the mercury cadmium telluride semiconductor between the photoelectric response region and the non-photoelectric response region, thereby separating the photoelectric response region and the non-photoelectric response region; During the etching process, the etching depth is controlled to retain the electrode interconnection region on the back side of the mercury cadmium telluride semiconductor.