Vertical tellurium-cadmium-mercury infrared detector and manufacturing method thereof
By setting electrodes on the upper and lower surfaces of the mercury cadmium tellurium detector and connecting the lower electrode to the substrate using indium columns to form a vertical electric field distribution, the problem of excessive power consumption of the detector in a low-temperature environment is solved, and higher stability and reliability are achieved.
Patent Information
- Application Number
- CN202411961686.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-04-04
AI Technical Summary
When the existing mercury cadmium tellurium detectors operate in low temperature environments, their power consumption is too high, exceeding the refrigeration capacity of the refrigerator, resulting in the inability to stably maintain the set target temperature.
A vertical mercury cadmium tellurium infrared detector was designed. By setting electrodes on the upper and lower surfaces of the mercury tellurium material layer and connecting the lower electrode with the sapphire substrate using an indium column to form a vertical electric field distribution, reducing the resistance and power consumption of the detector.
It effectively reduces the power consumption of the detector, reduces the demand for the cooling capacity of the refrigerator, and improves the stability and reliability of the detector in low-temperature environments.
Smart Images
Figure CN119767805A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of mercury cadmium telluride detectors, in particular to a vertical mercury cadmium telluride infrared detector and a manufacturing method thereof. Background Art
[0002] Mercury cadmium telluride photoconductive infrared detectors are widely used in the fields of train hot axle monitoring, forest fire prevention, gas composition detection, spectral analysis, etc. due to their outstanding advantages such as flexible and adjustable response band, high response rate, fast response speed, and simple manufacturing process.
[0003] In order to improve the sensitivity of the detector and reduce noise, mercury cadmium telluride detectors are usually placed in a low-temperature environment. In some extreme application scenarios, such as the very long-wave infrared detection band, the operating temperature of the mercury cadmium telluride detector must be lower than the liquid nitrogen temperature (77K), sometimes reaching around 40K. The low-temperature environment is generally provided by a Stirling refrigerator. According to the current technological status, the lower the target temperature, the smaller the Stirling's cooling capacity. However, mercury cadmium telluride photoconductive detectors require an external bias current when working. Especially when the number of working elements of the detector is relatively large, the power consumption generated will exceed the cooling capacity of the refrigerator, making it impossible to stabilize at the set target temperature during operation. Summary of the invention
[0004] The purpose of the present invention is to provide a vertical mercury cadmium telluride infrared detector and a manufacturing method thereof, which solves the problem that when the number of working elements of the existing detector is relatively large, the power consumption generated will exceed the cooling capacity of the refrigerator, making it impossible to stabilize at the set target temperature during operation.
[0005] To achieve the above object, the technical solution of the present invention is:
[0006] A vertical mercury cadmium telluride infrared detector comprises a substrate and a mercury cadmium telluride material layer having an anodic oxide layer arranged on the upper surface of the substrate; a lower electrode is arranged on the lower surface of the mercury cadmium telluride material layer, an upper electrode is arranged on the upper surface of the mercury cadmium telluride material layer, and a transition electrode layer is arranged on the upper surface of the substrate;
[0007] An indium column array is arranged between the lower electrode and the transition electrode layer, the upper end of the indium column is connected to the lower electrode, and the lower end of the indium column is connected to the transition electrode layer;
[0008] There is a double passivation layer on the anode oxide layer on the upper surface of the mercury cadmium telluride material layer, a through hole is opened in the double passivation layer, and an upper electrode is grown in the through hole.
[0009] The substrate is made of sapphire.
[0010] The double passivation layers are ZnS passivation layer and SiO 2 Passivation layer.
[0011] The transition electrode layer is a chromium-gold composite electrode layer, the chromium metal surface of the chromium-gold composite electrode layer is attached to the substrate, and the gold metal surface faces the lower electrode.
[0012] The upper electrode and the lower electrode are both indium-gold composite electrodes, and the indium metal surface of the indium-gold composite electrode is bonded to the mercury cadmium telluride material layer.
[0013] The method for manufacturing the vertical mercury cadmium telluride infrared detector as described above is characterized in that the specific steps are as follows:
[0014] Step 1: cleaning the mercury cadmium telluride material and polishing the lower surface of the mercury cadmium telluride material layer;
[0015] Step 2: Anodize the polished surface of the lower surface of the mercury cadmium telluride material layer, so that an anodized layer is attached to the lower surface of the mercury cadmium telluride material layer;
[0016] Step 3, corroding the anodic oxide layer on the lower surface of the mercury cadmium telluride material layer to grow a lower electrode;
[0017] Step 4, cleaning the sapphire substrate and growing a transition electrode layer on the upper surface of the substrate;
[0018] Step 5, growing indium column arrays on the transition electrode layer and the lower electrode respectively; interconnecting the mercury cadmium telluride material layer and the sapphire substrate by reverse welding through the indium columns, and filling epoxy glue between the transition electrode layer and the lower electrode;
[0019] Step 6, polishing and thinning the upper surface of the mercury cadmium telluride material layer, etching the photosensitive surface, and anodizing the upper surface and side surfaces of the mercury cadmium telluride material layer, so that an anodized layer is attached to the upper surface and side surfaces of the mercury cadmium telluride material layer;
[0020] Step seven, growing a double passivation layer on the anode oxide layer on the upper surface of the mercury cadmium telluride material layer;
[0021] Step eight, opening a hole in the double-layer passivation layer, and growing an upper electrode at the opening.
[0022] The lower electrode in step three and the upper electrode in step eight are indium-gold composite electrodes, and the indium metal surface of the indium-gold composite electrode is bonded to the mercury cadmium telluride material layer.
[0023] The transition electrode layer in step 4 is a chromium-gold composite electrode layer, the chromium metal surface of the chromium-gold composite electrode layer is attached to the substrate, and the gold metal surface faces the lower electrode.
[0024] The double passivation layer in step 7 is a ZnS passivation layer and a SiO 2 Passivation layer.
[0025] In step 7, a ZnS passivation layer is first grown on the anodic oxide layer on the upper surface of the HgCdTe material layer, and then a SiO2 passivation layer is grown on the ZnS passivation layer. 2 Passivation layer.
[0026] The advantages of the present invention are: 1. The electrodes are located on the upper and lower surfaces of the mercury cadmium telluride material layer, so that the electric field inside the detector is changed from the horizontal distribution of the prior art to the vertical distribution, which greatly reduces the resistance of the detector, and can even be reduced by more than 100 times. Under the same bias conditions, the power consumption of the detector can be effectively reduced, and the demand for the cooling capacity of the refrigerator when the detector works at a deep low temperature is alleviated to a great extent; 2. The present invention is easier to bias in a constant voltage mode and has better linearity, which is of great significance for the application of Fourier transform spectrometers; 3. The lower electrode is connected to the sapphire substrate through an indium column for signal extraction; the gap between the mercury cadmium telluride material layer and the sapphire substrate is filled with glue to improve the reliability of the entire detector. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 It is a schematic structural diagram of a vertical mercury cadmium telluride infrared detector of the present invention;
[0028] In the figure: 1-substrate; 2-transition electrode layer; 3-filling glue layer; 4-indium column; 5-lower electrode; 6-anodized layer; 7-mercury cadmium telluride material layer; 8-upper electrode; 9-ZnS passivation layer; 10-SiO 2 Passivation layer. DETAILED DESCRIPTION
[0029] The present invention is further described below in conjunction with the accompanying drawings, which are only used for exemplary description and cannot be understood as limiting the present invention.
[0030] In order to more concisely describe the present embodiment, some parts known to those skilled in the art but not related to the main content of the present invention are omitted in the drawings or descriptions. In addition, for the convenience of description, some parts in the drawings are omitted, enlarged or reduced, but they do not represent the size or entire structure of the actual product.
[0031] The invention discloses a vertical mercury cadmium telluride infrared detector, such as Figure 1 As shown, it includes a substrate 1 and a mercury cadmium telluride material layer 7 having an anodized layer 6 disposed on the upper surface of the substrate 1 ; preferably, the substrate 1 is a sapphire substrate, and the anodized layer 6 is wrapped around the outer surface of the mercury cadmium telluride material layer 7 .
[0032] A lower electrode 5 is arranged on the lower surface of the mercury cadmium telluride material layer 7, an upper electrode 8 is arranged on the upper surface of the mercury cadmium telluride material layer 7, and a transition electrode layer 2 is arranged on the upper surface of the substrate 1; an array of indium pillars 4 is arranged between the lower electrode 5 and the transition electrode layer 2, the upper ends of the indium pillars 4 are connected to the lower electrode 5, and the lower ends of the indium pillars 4 are connected to the transition electrode layer 2, and the lower electrode 5 and the transition electrode layer 2 are interconnected by reverse welding of the indium pillars 4, so as to lead the signal of the lower electrode 5 to the transition electrode layer 2.
[0033] Between the transition electrode layer 2 and the lower electrode 5 is a filling glue layer 3 for filling the gaps between the indium pillars 4. The filling glue is epoxy glue for improving the reliability of the entire detector.
[0034] A double-layer passivation layer is formed on the anodic oxide layer 6 on the upper surface of the mercury cadmium telluride material layer 7 . A through hole is formed in the double-layer passivation layer, and an upper electrode 8 is grown in the through hole.
[0035] Preferably, the double passivation layer is ZnS passivation layer 9 and SiO 2 The passivation layer 10 .
[0036] The transition electrode layer 2 is a chromium-gold composite electrode layer, the chromium metal surface of the chromium-gold composite electrode layer is attached to the substrate 1 , and the gold metal surface faces the lower electrode 5 .
[0037] The upper electrode 8 and the lower electrode 5 are both indium-gold composite electrodes, and the indium metal surface of the indium-gold composite electrode is bonded to the mercury cadmium telluride material layer 7 .
[0038] The manufacturing method of the vertical mercury cadmium telluride infrared detector mentioned above has the following specific steps:
[0039] Step 1: cleaning the mercury cadmium telluride wafer and polishing the lower surface of the mercury cadmium telluride material layer 7;
[0040] A four-step cleaning method is used, that is, the surface of the mercury cadmium telluride material layer 7 is cleaned with trichloroethylene, ether, acetone, and alcohol in sequence; the cleaned mercury cadmium telluride material layer 7 is attached to a flat glass plate with wax, and rough polishing and fine polishing are performed in sequence, with a thickness of about 10 μm.
[0041] Step 2: Anodize the polished surface of the lower surface of the mercury cadmium telluride material layer 7, and an anodized layer 6 is attached to the lower surface of the mercury cadmium telluride material layer 7;
[0042] Step three, corroding the anodic oxide layer 6 on the lower surface of the mercury cadmium telluride material layer 7, and growing the lower electrode 5; the lower electrode 5 is an indium gold composite electrode.
[0043] The polished surface is anodized, and then the anodized layer 6 is corroded with HCL solution to open holes, and an indium-gold composite lower electrode 5 is grown at the openings, with an indium metal thickness of 20 nm and a gold metal thickness of 300 nm.
[0044] Step 4, select double-polished transparent sapphire with a thickness of about 500μm, use a four-step cleaning method to clean the surface of the sapphire substrate 1, and grow a transition electrode layer 2 on the upper surface of the substrate 1; the transition electrode layer 2 is a chromium-gold composite electrode layer, the chromium metal thickness is 20nm, and the gold metal thickness is 500nm; the chromium metal surface of the chromium-gold composite electrode layer is bonded to the substrate 1, and the gold metal surface faces the lower electrode 5.
[0045] Step 5: grow an array of indium pillars 4 on the transition electrode layer 2 and the lower electrode 5, respectively, with a thickness of about 10 μm; use a cold press flip-chip method to interconnect the mercury cadmium telluride material layer 7 and the sapphire substrate 1, and then fill the gaps of the indium pillars 4 with epoxy glue;
[0046] Step 6, remove the HgCdTe wafer after the reverse welding from the glass plate, and then re-attach the lower surface of the sapphire substrate 1 to the glass plate with wax; then polish and thin the upper surface of the HgCdTe material layer 7, and etch the upper surface of the HgCdTe material layer 7 with an Ar ion beam to etch the photosensitive surface and define the shape of the photosensitive surface; and anodize the upper surface and side surfaces of the HgCdTe material layer 7 so that the upper surface and side surfaces of the HgCdTe material layer 7 are attached with an anodized layer 6;
[0047] Step 7: grow a double passivation layer on the anodic oxide layer 6 on the upper surface of the mercury cadmium telluride material layer 7; the double passivation layer is a ZnS passivation layer 9 and a SiO 2 The passivation layer 10 is firstly formed by growing a ZnS passivation layer 9 on the anodized layer 6, and then growing a SiO 2 Passivation layer 10: SiO 2 The main function of the passivation layer 10 is to isolate the ZnS passivation layer 9 from the air, and prevent the ZnS passivation layer 9 from being corroded by water vapor in the air.
[0048] The ZnS passivation layer 9 was grown by thermal evaporation with a thickness of 300 nm; the SiO 2 The passivation layer 10 has a thickness of 300 nm.
[0049] Step eight, using HF acid buffer and HCl solution to open holes in the double-layer passivation layer in turn, and growing an upper electrode 8 at the opening. The upper electrode 8 is an indium-gold composite electrode with an indium metal thickness of 20 nm and a gold metal thickness of 300 nm.
[0050] A coating machine is used to coat the HgCdTe wafer with coating protection, and then the wafer is diced.
[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. That is, any equivalent changes and modifications made according to the content of the patent application scope of the present invention should be within the technical scope of the present invention.
Claims
1. A vertical mercury cadmium telluride infrared detector, comprising a substrate (1) and a mercury cadmium telluride material layer (7) having an anodized layer (6) disposed on the upper surface of the substrate (1); characterized in that: A lower electrode (5) is arranged on the lower surface of the mercury cadmium telluride material layer (7), an upper electrode (8) is arranged on the upper surface of the mercury cadmium telluride material layer (7), and a transition electrode layer (2) is arranged on the upper surface of the substrate (1); An indium column (4) array is arranged between the lower electrode (5) and the transition electrode layer (2), the upper ends of the indium columns (4) are connected to the lower electrode (5), and the lower ends of the indium columns (4) are connected to the transition electrode layer (2); A double-layer passivation layer is provided on the anode oxide layer (6) on the upper surface of the mercury cadmium telluride material layer (7), a through hole is provided on the double-layer passivation layer, and an upper electrode (8) is grown in the through hole.
2. The vertical HgCdTe infrared detector according to claim 1, characterized in that: The substrate (1) is made of sapphire.
3. The vertical HgCdTe infrared detector according to claim 2, characterized in that: The double passivation layer is a ZnS passivation layer (9) and a SiO2 passivation layer (10) from bottom to top.
4. The vertical HgCdTe infrared detector according to claim 3, characterized in that: The transition electrode layer (2) is a chromium-gold composite electrode layer, the chromium metal surface of the chromium-gold composite electrode layer is bonded to the substrate (1), and the gold metal surface faces the lower electrode (5).
5. The vertical HgCdTe infrared detector according to claim 4, characterized in that: The upper electrode (8) and the lower electrode (5) are both indium-gold composite electrodes, and the indium metal surface of the indium-gold composite electrode is bonded to the mercury cadmium telluride material layer (7).
6. The method for manufacturing a vertical HgCdTe infrared detector according to claim 5, characterized in that: The specific steps are as follows: Step 1: cleaning the mercury cadmium telluride material and polishing the lower surface of the mercury cadmium telluride material layer (7); Step 2: Anodize the polished surface of the lower surface of the mercury cadmium telluride material layer (7), and attach the anodized layer (6) to the lower surface of the mercury cadmium telluride material layer (7); Step 3, corroding the anodic oxide layer (6) on the lower surface of the mercury cadmium telluride material layer (7) to grow a lower electrode (5); Step 4: cleaning the sapphire substrate (1) and growing a transition electrode layer (2) on the upper surface of the substrate (1); Step 5: growing an array of indium pillars (4) on the transition electrode layer (2) and the lower electrode (5) respectively; interconnecting the mercury cadmium telluride material layer (7) and the sapphire substrate (1) by reverse welding through the indium pillars (4), and filling epoxy glue between the transition electrode layer (2) and the lower electrode (5); Step 6, polishing and thinning the upper surface of the mercury cadmium telluride material layer (7), etching the photosensitive surface, and anodizing the upper surface and side surfaces of the mercury cadmium telluride material layer (7), so that the upper surface and side surfaces of the mercury cadmium telluride material layer (7) are attached with an anodized layer (6); Step seven, growing a double passivation layer on the anode oxide layer (6) on the upper surface of the mercury cadmium telluride material layer (7); Step eight, opening a hole in the double-layer passivation layer, and growing an upper electrode (8) at the opening.
7. The method for manufacturing a vertical HgCdTe infrared detector according to claim 6, characterized in that: The lower electrode (5) in step three and the upper electrode (8) in step eight are indium-gold composite electrodes, and the indium metal surface of the indium-gold composite electrode is bonded to the mercury cadmium telluride material layer (7).
8. The method for manufacturing a vertical HgCdTe infrared detector according to claim 6, characterized in that: The transition electrode layer (2) in step 4 is a chromium-gold composite electrode layer, the chromium metal surface of the chromium-gold composite electrode layer is bonded to the substrate (1), and the gold metal surface faces the lower electrode (5).
9. The method for manufacturing a vertical HgCdTe infrared detector according to claim 6, characterized in that: The double passivation layer in step seven is a ZnS passivation layer (9) and a SiO2 passivation layer (10).
10. The method for manufacturing a vertical HgCdTe infrared detector according to claim 9, characterized in that: In step seven, a ZnS passivation layer (9) is first grown on the anode oxide layer (6) on the upper surface of the mercury cadmium telluride material layer (7), and then a SiO2 passivation layer (10) is grown on the ZnS passivation layer (9).