A P + -vN + Mercury cadmium telluride mesa heterojunction infrared detector and its fabrication method

Abstract

This invention discloses a P + -v-N + A novel mercury cadmium telluride mesa heterojunction infrared detector and its fabrication method, utilizing liquid-phase epitaxy to achieve P + -v material structure fabrication: N is prepared on the surface of the v-shaped layer using a back-implantation method. + After annealing, a three-layer hetero-doped material structure was fabricated, and P was then fabricated using device fabrication technology. + -v-N + This invention relates to a P-type mercury cadmium telluride mesa heterojunction detector. It utilizes the P-type wide-bandgap heterolayer growth process to achieve interfacial interdiffusion, reducing interface defect density and improving interface quality. Based on the ability to control raw material impurities above 7N and the self-purification characteristics of the growth process, it achieves stable control of low-concentration V-type layer impurities. Furthermore, it utilizes a high-resistivity transition layer formed by epitaxy and N-type metallurgical layer formed by boron ion implantation. + Layer; RTP fast annealing is used to repair injection damage. This invention can effectively suppress recombination current. Its surface heteromaterial forms a band modulation structure that suppresses tunneling current and surface leakage current. Compared with P-on-n devices, it can theoretically reduce dark current by two orders of magnitude and improve device performance.

Description

Technical Field

[0001] This invention belongs to the field of mercury cadmium telluride infrared detector technology, and particularly relates to a P + -vN + A novel mercury cadmium telluride mesa heterojunction infrared detector and its fabrication method. Background Technology

[0002] Infrared focal plane array detectors have been widely used in military, industrial, environmental, and medical fields. Among the many infrared detection materials, mercury cadmium telluride (Hg) is a notable example. 1-x Cd x Te materials possess the advantage of high quantum efficiency. By changing the composition x, their band gaps can satisfy infrared detection within three atmospheric windows: 1~3μm, 3~5μm, and 8~14μm, demonstrating significant advantages in fundamental physical properties. Mercury cadmium telluride infrared focal plane array detectors have reached their third generation, characterized by large arrays, very long wavelengths, multicolor technology, and HOT devices, thus dominating the high-end infrared detection field.

[0003] The main technical routes for mercury cadmium telluride infrared detectors include several structures such as N-on-p, P-on-n, and Pin. In the current mature device processes, the quantum efficiency of infrared detectors is above 80%, and even reaches 100%. From the perspective of photon utilization efficiency, there is not much potential to significantly improve the performance of the device. In contrast, by reducing dark current and increasing operating temperature, the performance of mercury cadmium telluride infrared detectors can be further improved and the cost reduced.

[0004] In terms of current development, the p-on-n structure outperforms the n-on-p structure in terms of dark current suppression, reducing dark current by two orders of magnitude compared to the n-on-p structure. The fully depleted pin structure outperforms the p-on-n structure, further reducing dark current by one to two orders of magnitude compared to the p-on-n structure. Based on the doping characteristics of the i-layer, pin structures are further divided into P... + / π / N + (Layer i is a weak P type) and P + / v / N + (The i-th layer is a weak n-type) structure. The main technical approach is to use MBE technology to grow multilayer material structures, where P + and N + The layer is a high-resistivity structure, and the device structure is fabricated using ion implantation or in-situ doping and activation annealing processes. Currently, the more mature technical solution is the fully depleted P-type structure. + / v / N + Structures in which the typical V-layer concentration is less than 5E13 / cm 3 level.

[0005] In the process of preparing multilayer mercury cadmium telluride (McCdT) materials using molecular beam epitaxy (MBE), due to technical limitations, the surface macroscopic defect density of McCdT materials is relatively high, more than one order of magnitude higher than that of LPE. For commonly used p-type impurities (As doping), whether in-situ growth doping or ion implantation, a high-temperature annealing process is required for activation, which leads to complex impurity diffusion. The high-temperature process also causes interdiffusion at the heterolayer interface, reducing the effectiveness of the material structure. Furthermore, MBE technology has great difficulty in controlling the background impurities of McCdT materials, and it is difficult to stably control them at a low n-type level. Summary of the Invention

[0006] The technical problem to be solved by this invention is to overcome the shortcomings of the above-mentioned preparation methods and provide a method for realizing P using liquid phase epitaxy (LPE) technology. + The basic concept of the preparation method of -v material structure is based on the above P + N-type materials are fabricated on the surface of the V-shaped layer by back implantation within the naturally formed high-resistivity transition layer at the bottom of the V-shaped material structure. + Layered structure to implement P + -vN + Type-2 tellurium cadmium-mercury mesa heterojunction detector.

[0007] This invention utilizes the growth process of a P-type wide-bandgap heterolayer to achieve interfacial interdiffusion, effectively reducing the interface defect density and improving interface quality. It employs mercury-rich liquid-phase epitaxy to achieve an activation rate of over 90% for P-type impurities (As), eliminating the need for high-temperature annealing activation and effectively avoiding unintended impurity diffusion and heterolayer interface diffusion problems caused by complex annealing processes. Based on the raw material impurity control capability of 7N and above and the self-purification characteristics of the growth process, it achieves stable control of low-concentration V-type layer impurities, with impurity concentrations generally at the low to medium E13 level. It utilizes the naturally formed high-resistivity transition layer in the liquid-phase epitaxy process for B ion implantation to form N... + The three-layer hetero-doped material was prepared using RTP rapid annealing to repair implantation damage. Based on these technical advantages, a three-layer hetero-doped material and P were fabricated. + -vN + The non-equilibrium depletion device structure can effectively suppress recombination current. The surface heterogeneous material forms a band modulation structure, which can effectively suppress tunneling current and surface leakage current. Compared with P-on-n devices, this device structure can theoretically reduce dark current by two orders of magnitude, thereby improving device performance.

[0008] This invention provides a P + -vN + A novel mercury cadmium telluride mesa heterojunction infrared detector and its fabrication method, used to solve the problem of P +-vN + This addresses the fabrication challenges of the mercury cadmium telluride mesa heterojunction infrared detector and aims to further improve the performance of mercury cadmium telluride planar junction detectors.

[0009] According to the first aspect, the embodiments of the present invention provide P + -vN + A type of mercury cadmium telluride mesa heterojunction infrared detector, comprising sequentially stacked components:

[0010] Substrate material layer, the material is selected from Cd 1-x1 Zn x1 One of the Te or Si-based alternative substrates;

[0011] N + Wide bandgap heterolayer, material selected from Hg 1-x2 Cd x2 Te;

[0012] V-shaped absorber layer, material selected from Hg 1-x3 Cd x3 Te;

[0013] P + Wide bandgap heterolayer, material selected from Hg 1-x4 Cd x4 Te;

[0014] The passivation layer is made of one or more of the following materials: CdTe, ZnS, SiN, and BN.

[0015] Contact electrode layer;

[0016] The V-shaped absorption layer and P + Wide bandgap heterolayers are grown via horizontal or vertical liquid phase epitaxy; N is prepared on the surface of the V-shaped absorber layer using back implantation. + Wide bandgap heterolayer;

[0017] x1, x2, x3, and x4 are all less than 1. The response wavelength is adjusted by regulating x2 and x3, which is used to change the response wavelength of the detector; x4 > x2 > x3.

[0018] The passivation layer covers at least a portion of the area of ​​the p-type wide bandgap heterolayer in the orthogonal projection direction, and the portion of the passivation layer not covering the p-type wide bandgap heterolayer is an electrode hole;

[0019] The contact electrode layer is in contact with the electrode hole of the p-type wide bandgap heterolayer and its projected area is larger than and covers the electrode hole.

[0020] P according to an embodiment of the present invention + -vN +A novel P-type mercury cadmium telluride mesa heterojunction infrared detector and its fabrication method are disclosed. This method utilizes the growth process of a P-type wide-bandgap heterolayer to achieve interfacial interdiffusion and an activation rate of over 90% for P-type impurities. Compared to MBE-grown P-type... + -vN + The LPE technology effectively avoids the complex annealing process and unexpected impurity diffusion problems caused by impurity activation in n-type heterojunction devices. Compared with MBE technology, LPE technology has a greater advantage in controlling the level of residual impurities. The residual impurity control level of MBE technology in China is about a low coefficient E14, while LPE technology can control the residual impurities of the n-type layer to a medium coefficient E13 level. It can form an effective fully depleted device structure, effectively suppress recombination current, and form a band modulation structure with surface heteromaterials, which can effectively suppress tunneling current and surface leakage current. Compared with P-on-n devices, this device structure can theoretically reduce dark current by two orders of magnitude and improve device performance.

[0021] According to some embodiments of the present invention, both the n-type absorber layer and the n-type wide bandgap heterolayer are made of Hg. 1-x Cd x Te, where the value of x is less than 1.

[0022] According to some embodiments of the present invention, the n-type absorber layer is an unintentionally doped material, and the remaining impurities are n-type with a concentration range of 4E13cm⁻¹. -3 Up to 6E13cm -3 Hg 1-x Cd x The x value in Te ranges from 0.1 to 0.4.

[0023] According to some embodiments of the present invention, the passivation layer thickness ranges from 500 angstroms to 20,000 angstroms, and the selected materials include, but are not limited to, CdTe, ZnS, SiN, and BN.

[0024] According to some embodiments of the present invention, the p-type wide bandgap heterolayer has an As doping concentration ranging from 5E16cm⁻³ to 5E17cm⁻³. -3 Hg 1-x Cd x The x value in Te ranges from 0.23 to 0.6.

[0025] According to the second aspect, embodiments of the present invention provide methods for preparing P according to some embodiments of the present invention. + -vN + A mercury cadmium telluride planar heterojunction detector, the method comprising:

[0026] A V-shaped absorption layer is grown on the substrate material layer;

[0027] P was prepared by secondary growth on the V-shaped absorber layer. +A wide bandgap heterolayer;

[0028] In P + Photolithography is performed on the surface of the wide bandgap heterolayer. After development, ground holes are formed. A certain depth of mercury cadmium telluride material is removed by etching or etching processes to form ground holes. The bottom of the holes is 1.5-2.5 micrometers away from the substrate surface.

[0029] In P + Photolithography is performed on the surface of the wide bandgap heterostructure. After development, an isolation region is formed. The mercury cadmium telluride material of a certain depth is removed by etching or corrosion processes to form a pixel isolation. The depth of the isolation region is about 1.5-5.5 micrometers.

[0030] In P + A passivation layer is grown on the surface of a wide bandgap heterostructure using magnetron sputtering, thermal evaporation, or MBE processes.

[0031] Photolithography is performed on the surface of the passivation layer. After development, the electrode holes and ground holes are exposed. The passivation layer is removed by etching or corrosion outside the photoresist protected area to prepare the contact holes.

[0032] The contact electrode metal layer was prepared using a thermal evaporation process.

[0033] The material is immersed in a stripping solution, and the photoresist and surface metal layer on the protected area material surface are removed by a stripping process to obtain P. + -V-type mercury cadmium telluride platform structure;

[0034] Indium pillars are used to solder the photosensitive element chip to the readout circuit;

[0035] After filling and curing the space between the photosensitive chip and the readout circuit with curing adhesive, a back thinning process is performed to completely remove the substrate layer.

[0036] On the thinned surface of the chip back, B is performed. + Ion implantation process to form N + Wide bandgap heterolayer;

[0037] The back of the chip is subjected to RTP fast annealing to repair some injection damage and complete the P process. + -vN + Chip fabrication.

[0038] Beneficial effects of the present invention

[0039] P according to an embodiment of the present invention + -vN +The novel mercury cadmium telluride detector utilizes the growth process of a P-type wide-bandgap heterolayer to achieve interfacial interdiffusion and an activation rate of over 90% for P-type impurities, effectively avoiding the complex annealing process and unintended impurity diffusion problems caused by impurity activation. It controls the remaining impurities in the n-type layer to the E13 power level, forming an effective fully depleted device structure that effectively suppresses recombination current. The surface heteromaterial forms a band modulation structure, effectively suppressing tunneling current and surface leakage current. Compared to P-on-n devices, this device structure theoretically reduces dark current by two orders of magnitude, improving device performance.

[0040] Through experimental comparison, thanks to the natural passivation effect of the surface heterolayer and the band modulation structure, the dark current level of this structure device at low temperature is more than an order of magnitude lower than that of P-on-n devices of the same wavelength, and the device response wavelength reaches 10.5 micrometers (77K). Attached Figure Description

[0041] Figure 1 P according to an embodiment of the present invention + -vN + A schematic diagram of a type-2 mercury cadmium telluride mesa heterojunction infrared detector and its fabrication method.

[0042] Figure 2 As shown in step S100 of the embodiment of the present invention, P + -vN + A schematic diagram of a type-2 mercury cadmium telluride mesa heterojunction infrared detector and its fabrication method.

[0043] Figure 3 As shown in step S200 of the embodiment of the present invention, P + -vN + A schematic diagram of a type-2 mercury cadmium telluride mesa heterojunction infrared detector and its fabrication method.

[0044] Figure 4 As shown in step S300 of the embodiment of the present invention, P + -vN + A schematic diagram of a type-2 mercury cadmium telluride mesa heterojunction infrared detector and its fabrication method.

[0045] Figure 5 As shown in step S400 of the embodiment of the present invention, P + -vN + A schematic diagram of a type-2 mercury cadmium telluride mesa heterojunction infrared detector and its fabrication method.

[0046] Figure 6 As shown in step S500 of the embodiment of the present invention, P + -vN + A schematic diagram of a mercury cadmium telluride mesa heterojunction infrared detector and its fabrication method.

[0047] Figure 7 As shown in step S600 of the embodiment of the present invention, P + -vN + A schematic diagram of a type-2 mercury cadmium telluride mesa heterojunction infrared detector and its fabrication method.

[0048] Figure 8 As shown in step S700 of the embodiment of the present invention, P + -vN + A schematic diagram of a type-2 mercury cadmium telluride mesa heterojunction infrared detector and its fabrication method.

[0049] Figure 9 As shown in step S800 of the embodiment of the present invention, P + -vN + A schematic diagram of a type-2 mercury cadmium telluride mesa heterojunction infrared detector and its fabrication method.

[0050] Figure 10 As shown in step S900 of the embodiment of the present invention, P + -vN + A schematic diagram of a type-2 mercury cadmium telluride mesa heterojunction infrared detector and its fabrication method.

[0051] Figure 11 As shown in step S1000 of the embodiment of the present invention, P + -vN + A schematic diagram of a type-2 mercury cadmium telluride mesa heterojunction infrared detector and its fabrication method.

[0052] Figure 12 As shown in step S1100 of the embodiment of the present invention, P + -vN + A schematic diagram of a type-2 mercury cadmium telluride mesa heterojunction infrared detector and its fabrication method.

[0053] Figure 13 As shown in step S1200 of the embodiment of the present invention, P + -vN + A schematic diagram of a type-2 mercury cadmium telluride mesa heterojunction infrared detector and its fabrication method.

[0054] Figure 14 As shown in step S1300 of the embodiment of the present invention, P + -vN + A schematic diagram of a type-2 mercury cadmium telluride mesa heterojunction infrared detector and its fabrication method.

[0055] Figure 15 P according to an embodiment of the present invention + -vN +A flowchart illustrating the fabrication process of a mercury cadmium telluride mesa heterojunction infrared detector.

[0056] Figure label:

[0057] Substrate material layer 1, V-type absorber layer 2, P + 3. Wide bandgap heterostructure; 4. Ground electrode region; 5. Mesa isolation region; 6. Passivation layer; P + Area electrode hole 7, N + 8. Electrode hole; 9. Photoresist; 10. Electrode metal layer; 11. Electrode metal; 12. Readout circuit; 13. Interconnect indium pillar; N + Wide bandgap heterolayer 14. Detailed Implementation

[0058] To make the objectives, content, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The accompanying drawings form part of this application and are used to illustrate the principles of the present invention.

[0059] like Figure 1 and Figure 2 As shown, the P provided in the embodiment of the present invention + -vN + The novel mercury cadmium telluride mesa heterojunction infrared detector and its fabrication method include a substrate material layer 1 stacked sequentially, and N2 implanted... + Wide bandgap heterolayer 14, n-type absorber layer 2, P + The chip includes a wide bandgap heterogeneous layer 3, a passivation layer 6, a contact electrode layer 11, an interconnect indium pillar 12, and a readout circuit 13. The readout circuit and the chip are filled with a curing adhesive.

[0060] P + After the growth of the wide bandgap heterolayer 3, an array of p-type regions 4 is formed by photolithography, creating independent pixels. In the actual device fabrication process, detectors of different specifications and shapes can be formed by adjusting the shape and size of the photolithographic pattern. Here, only one example is used. Figure 2 The rectangular area shown is for illustrative purposes only.

[0061] like Figure 1 As shown, the passivation layer 6 covers the pixel isolation area and part of P in the orthographic projection direction. + The uncovered portion of the layer surface is the electrode contact hole.

[0062] P according to an embodiment of the present invention + -vN +This novel mercury cadmium telluride mesa heterojunction detector utilizes the P-type wide-bandgap heterolayer growth process to achieve interfacial interdiffusion, effectively reducing interfacial defect density and improving interfacial quality. It employs mercury-rich liquid-phase epitaxy to achieve an activation rate of over 90% for P-type impurities, effectively avoiding the complex annealing process and unintended impurity diffusion problems associated with impurity activation. The mature liquid-phase epitaxy technology can stably control the remaining impurities in the V-type absorber layer 2, with impurity concentrations typically at the E13 power level. Based on these technological advantages, the fabricated P-type... + -vN + The fully depleted device structure can effectively suppress recombination current. The surface heterogeneous material forms a band modulation structure, which can effectively suppress tunneling current and surface leakage current. Compared with P-on-n devices, this device structure can theoretically reduce dark current by two orders of magnitude, further improving device performance.

[0063] like Figure 1 and Figure 2 As shown, according to some embodiments of the present invention, N is injected + Wide bandgap heterolayer 14, n-type absorber layer 2 and P + The material of the bandgap heterolayer 3 is Hg 1-x Cd x The value of Te,x is less than 1. The response wavelength is adjusted by adjusting the component (x value), thereby changing the response wavelength of the detector according to different detection requirements.

[0064] like Figure 1 As shown, according to some embodiments of the present invention, P + Wide bandgap heterolayer 3 is made of As-doped material, with an As doping concentration ranging from 5E to 16cm⁻¹. -3 Up to 5E17cm -3 Hg 1-x Cd x The x value in Te ranges from 0.25 to 0.6, and P + The x-value of the wide bandgap heterolayer 3 is higher than that of the v-type absorbing layer 2.

[0065] like Figure 1 As shown, according to some embodiments of the present invention, the thickness of the passivation layer 6 ranges from 500 angstroms to 20,000 angstroms, and the selected materials include, but are not limited to, CdTe, ZnS, SiN, BN, and combinations thereof.

[0066] The P provided in the embodiments of the present invention + -vN + The fabrication method of the type-2 mercury cadmium telluride mesa heterojunction infrared detector and its preparation method are used to prepare P in some embodiments of the present invention. + -vN + A planar heterojunction detector for mercury cadmium telluride, the method includes:

[0067] S100: As Figure 2 As shown, a V-shaped absorption layer is grown on the substrate material layer.

[0068] S200: such as Figure 3 As shown, a secondary growth is performed on the V-shaped absorption layer to grow P. + Wide bandgap heterogeneous layer.

[0069] S300: such as Figure 4 As shown, in P + Photolithography is performed on the wide bandgap heterolayer. After development, the ground line region is exposed. After etching the ground line holes, the chip is cleaned and the resist is removed. The bottom of the ground line hole is about 1-2 micrometers away from the interface between the substrate and the V-shaped absorption layer.

[0070] S400: such as Figure 5 As shown, in P + Photolithography is performed on the heterogeneous layer with a wide bandgap. After development, the surface isolation area is exposed. After etching and etching, the chip is cleaned and the resist is removed.

[0071] S500: such as Figure 6 As shown, a passivation layer is prepared on the material surface by magnetron sputtering, thermal evaporation or MBE method, and then annealed under mercury-rich conditions.

[0072] S600: such as Figure 7 As shown, photolithography is performed on the surface of the passivation layer. In the area where the photoresist is exposed, etching / corrosion is used to remove the passivation layer and a small portion of the thin film material to create a contact hole, and then the photoresist is removed.

[0073] S700: such as Figure 8 As shown, photolithography is performed on the material surface, and after development, the area where the contact electrode layer needs to be grown is exposed.

[0074] S800: such as Figure 9 As shown, the metal of the contact electrode layer is grown using a thermal evaporation process.

[0075] S900: such as Figure 10 As shown, the detector is immersed in a stripping solution, and the photoresist and the metal layer on the surface of the photoresist are stripped off through a stripping process to form a photosensitive element array.

[0076] S1000: As Figure 11 As shown, indium pillars are used to solder the photosensitive chip to the readout circuit.

[0077] S1100: As Figure 12 As shown, after filling and curing the photosensitive chip and the readout circuit with curing adhesive, a back thinning process is performed to completely remove the substrate layer.

[0078] S1200: such as Figure 13As shown, B is performed on the thinned surface of the chip. + Ion implantation process to form N + Wide bandgap heterolayer.

[0079] S1300: Performs RTP fast annealing on the back of the chip to repair some injection damage and complete the P process. + -vN + Chip fabrication, such as Figure 14 As shown.

[0080] In some embodiments of the present invention, the V-type absorber layer 2 and the p-type wide bandgap heterolayer are grown by horizontal liquid phase epitaxy (LPE) or vertical liquid phase epitaxy (VLPE), and the p-type doping is done with arsenic (As).

[0081] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0082] First, such as Figure 2 As shown, a V-type absorber layer 2 is grown using Si, GaAs, or cadmium zinc telluride as the substrate material layer, employing LPE or VLPE technology. The Hg content of the V-type absorber layer 2 is... 1-x Cd x The x-value of Te is 0.15-0.4, and the n-type concentration is 1×10⁻⁶. 13 cm -3 Up to 5×10 13 cm -3 The structure of this invention is prepared based on this material.

[0083] like Figure 3 As shown, a p-type wide bandgap heterolayer is prepared by secondary growth on the v-type absorber layer 2 material. The Hg of the p-type wide bandgap heterolayer 3 is then determined. 1-x Cd x The x-value of Te is 0.2-0.5, higher than that of the V-type absorber layer 2, and the p-type concentration is 1×10⁻⁶. 17 cm -3 Up to 5×10 17 cm -3 .

[0084] like Figure 4 As shown, photolithography is performed on the p-type wide bandgap heterolayer. After development, the ground line region is exposed. After etching the ground line holes, the chip is cleaned and the resist is removed. The bottom of the ground line hole is about 1.5 micrometers away from the interface between the substrate and the V-type absorption layer 2.

[0085] like Figure 5 As shown, in P +Photolithography is performed on the heterogeneous layer with a wide bandgap. After development, the surface isolation area is exposed. ICP etching is performed to a depth of 1.5 micrometers, followed by etching with 0.5% bromomethanol solution for 30 seconds. The chip is then cleaned and the resist is removed.

[0086] like Figure 6 As shown, a CdTe passivation layer with a thickness of 3000 Å was prepared on the material surface by magnetron sputtering and annealed under mercury saturation conditions (230 degrees Celsius / 24h).

[0087] like Figure 7 As shown, photolithography is performed on the surface of the passivation layer. In the area where the photoresist is exposed, ICP etching / etching is used to remove the passivation layer and a small portion of the thin film material to prepare a contact hole with a depth of about 5000 angstroms, and the photoresist is removed.

[0088] like Figure 8 As shown, photolithography is performed in the pixel area, and photoresist 8 covers the chip surface. After development, the area where the contact electrode layer 6 needs to be grown is exposed, and the photoresist thickness is greater than 3 micrometers.

[0089] like Figure 9 As shown, the metal of the contact electrode layer 6 is grown using a thermal evaporation process, such as a three-layer metal of Cr (1000 Å) + Pt (2000 Å) + Au (1000 Å).

[0090] like Figure 10 As shown, the detector is immersed in a stripping solution, and through a stripping process, the photoresist and the metal layer on the surface of the photoresist are removed, forming... Figure 1 The photosensitive element array shown.

[0091] like Figure 11 As shown, indium pillars are used to couple the photosensitive element chip to the readout circuit.

[0092] like Figure 12 As shown, after filling and curing the photosensitive chip and the readout circuit with curing adhesive, a back thinning process is performed to completely remove the substrate layer.

[0093] like Figure 13 As shown, B is performed on the thinned surface of the chip. + Ion implantation process to form N + Wide bandgap heterolayer, n-type concentration is approximately 1×10 17 cm -3 .

[0094] like Figure 14 As shown, the back of the chip is subjected to RTP fast annealing to repair some injection damage and complete the P process. + -vN + Chip fabrication, obtaining Figure 1 The detector structure is shown.

[0095] Figure 15 P according to an embodiment of the present invention + -vN + A flowchart illustrating the fabrication process of a mercury cadmium telluride mesa heterojunction infrared detector.

[0096] This technical approach effectively avoids the need for fabricating mercury cadmium telluride heterojunction materials based on MBE, and the mesa P + -vN + In heterojunction technology, controlling impurity concentration is difficult, impurities require complex heat treatment processes to activate, and unintended impurity and heterojunction interface component diffusion problems are easily caused. Furthermore, the material preparation process is immature, resulting in low mass production capacity. Compared to mesa P-type heterojunction technology... + -vN + Heterojunction, this invention is based on mature liquid phase epitaxy technology and B + Ion implantation technology offers high impurity control and low interface defects, which helps reduce dark current and improve device performance.

Claims

1. A P + -vN + A type of mercury cadmium telluride mesa heterojunction infrared detector, characterized in that... Including those set in a sequential stacking order: Substrate material layer, the material is selected from Cd 1-x1 Zn x1 One of the Te or Si-based alternative substrates; N + Wide bandgap heterolayer, material selected from Hg 1-x2 Cd x2 Te; V-shaped absorber layer, material selected from Hg 1-x3 Cd x3 Te; P + Wide bandgap heterolayer, material selected from Hg 1-x4 Cd x4 Te; The passivation layer is made of one or more of the following materials: CdTe, ZnS, SiN, and BN. Contact electrode layer; The V-shaped absorption layer and P + Wide bandgap heterolayers are grown via horizontal or vertical liquid phase epitaxy; N is prepared on the surface of the V-shaped absorber layer using back implantation. + Wide bandgap heterolayer; x1, x2, x3, and x4 are all less than 1. The response wavelength is adjusted by adjusting x2 and x3 to change the response wavelength of the detector; x4 > x2 > x3.

2. The infrared detector according to claim 1, characterized in that, The V-type absorber layer is an undoped material, and the residual n-type impurity concentration ranges from 1E13cm⁻¹. -3 Up to 5E13cm -3 The value of x3 ranges from 0.1 to 0.

4.

3. The infrared detector according to claim 1, characterized in that, The P + The wide bandgap heterolayer material is an As-doped material with an impurity concentration ranging from 5E16cm⁻¹. -3 Up to 5E17cm -3 The x4 value ranges from 0.23 to 0.

6.

4. The infrared detector according to claim 1, characterized in that, The passivation layer covers at least a portion of the area of ​​the p-type wide bandgap heterolayer in the orthogonal projection direction.

5. The infrared detector according to claim 1, characterized in that, The portion of the passivation layer not covering the p-type wide bandgap heterolayer is an electrode hole.

6. The infrared detector according to claim 1, characterized in that, The contact electrode layer is in contact with the electrode hole of the p-type wide bandgap heterolayer and its projected area is larger than and covers the electrode hole.

7. The infrared detector according to claim 1, characterized in that, The contact electrode layer has a positive projection area of ​​the contact electrode that is larger than and covers the contact hole.

8. The infrared detector according to claim 1, characterized in that, The passivation layer thickness ranges from 500 angstroms to 20,000 angstroms.

9. A P as described in any one of claims 1 to 8 + -vN + A method for fabricating a mercury cadmium telluride mesa heterojunction infrared detector, characterized in that... include: A V-shaped absorption layer is grown on the substrate material layer; P was prepared by secondary growth on the V-shaped absorber layer. + A wide bandgap heterolayer; In P + Photolithography is performed on the surface of the wide bandgap heterolayer. After development, ground holes are formed. A certain depth of mercury cadmium telluride material is removed by etching or etching processes to form ground holes. The bottom of the holes is 1.5-2.5 micrometers away from the substrate surface. In P + Photolithography is performed on the surface of the bandgap heterogeneous layer. After development, an isolation area is formed. A certain depth of mercury cadmium telluride material is removed by etching or corrosion processes to form a pixel isolation. In P + A passivation layer is grown on the surface of a wide bandgap heterostructure using magnetron sputtering, thermal evaporation, or MBE processes. Photolithography is performed on the surface of the passivation layer. After development, the electrode holes and ground holes are exposed. The passivation layer is removed by etching or corrosion outside the photoresist protected area to prepare the contact holes. The contact electrode metal layer was prepared using a thermal evaporation process. The material is immersed in a stripping solution, and the photoresist and surface metal layer on the protected area material are removed by a stripping process to obtain P. + -V-type mercury cadmium telluride platform structure; Indium pillars are used to solder the photosensitive element chip to the readout circuit; After filling and curing the space between the photosensitive chip and the readout circuit with curing adhesive, a back thinning process is performed to completely remove the substrate layer. On the thinned surface of the chip back, B is performed. + Ion implantation process to form N + Wide bandgap heterolayer; The back of the chip is subjected to RTP fast annealing to repair some injection damage and complete the P process. + -vN + Fabrication of a mesa heterojunction infrared detector.

10. The preparation method according to claim 6, characterized in that, V-shaped absorber layer and P were prepared using mercury-rich vertical liquid phase epitaxy. + A wide bandgap heterolayer is used to form a bilayer compositional heterostructure; N is prepared using a back-implantation method. + Wide bandgap heterolayer.

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