P-on-n type mercury cadmium telluride pixel-level in-situ grown array detector and preparation method thereof

Abstract

This invention provides a P-on-n type mercury cadmium telluride (HCd) heterojunction detector with pixel-level in-situ growth. It is characterized by comprising, from bottom to top, a substrate material layer, an n-type absorption layer, a passivation isolation grid layer isolating pixels, an array of P-type cap regions located within the isolation grid of the passivation isolation grid layer, a passivation layer covering the passivation isolation grid layer and the array of P-type cap regions, electrode contact holes disposed within the array of P-type cap regions but not covered by the passivation layer, and a contact electrode layer disposed within the electrode contact holes. By isolating the HCd heterojunction material into independent pixels, allowing interdiffusion at the interface of the grown P-type cap regions, a HCd P-on-n heterojunction detector is obtained. This effectively avoids damage to the HCd material, prevents leakage due to poor passivation layer coverage and interface compactness, reduces interface defects, effectively suppresses tunneling current, and improves detector performance.

Description

Technical Field

[0001] This invention relates to detectors and their fabrication methods, particularly to a P-on-n type mercury cadmium telluride pixel-level in-situ grown array detector and its fabrication method, belonging to the field of infrared detector design and manufacturing technology. Background Technology

[0002] Infrared focal plane array detectors are widely used in military, industrial, environmental, and medical fields. Among the many materials used in infrared detectors, mercury cadmium telluride (HCDT) stands out for its high quantum efficiency. By changing the composition x, its bandgap can meet the infrared detection requirements of three atmospheric windows: 1-3 μm, 3-5 μm, and 8-14 μm, demonstrating significant advantages in fundamental physical properties. HCDT infrared focal plane array detectors have reached their third generation, with the main technical routes including N-on-p and P-on-n types. Currently, the quantum efficiencies of infrared detectors produced by relatively mature infrared detector manufacturing processes are all above 80%, even reaching 100%. From the perspective of optical signal alone, the potential for significantly improving the performance of infrared detectors is limited. In contrast, by reducing dark current, the performance of HCDT infrared detectors can be improved by several orders of magnitude. In N-on-p and P-on-n type infrared focal plane detector structures, the P-on-n type infrared detector has a significant advantage in reducing dark current, with a reduction of up to two orders of magnitude. Existing fabrication routes for P-on-n type infrared focal plane detectors are divided into two types: planar homojunction (implantation junction formation) and mesa heterojunction (growth junction formation).

[0003] In mesa heterojunction technology, mercury cadmium telluride (MCH) material is in-situ doped with As, resulting in high activation rate. Through liquid phase epitaxy, indium (In)-doped n-type MCH material is first grown on the substrate, followed by As-doped p-type MCH material. After growth, a suitable activation annealing process is performed to form a pn junction. The n-type layer is the absorption layer, with a thickness generally above 5 μm, while the p-type layer is thinner, generally within 2 μm. The p-type layer has a higher Cd content than the n-type layer, resulting in a larger bandgap and greater material stability. This is beneficial for reducing tunneling current and noise, and its low-temperature performance is superior to that of homojunctions. In addition, in the mesa heterojunction process, mercury cadmium telluride array detectors need to isolate adjacent pixel pn junctions. Generally, etching / corrosion processes are used to isolate the p-type layer of each pixel. Since the mesa fabrication process inevitably damages the mercury cadmium telluride material, a large number of free sidewall surfaces are introduced into the process. These surfaces need to be finely passivated in subsequent processes. In addition, the poor coverage and interface density of the sidewall passivation layer of the mesa heterojunction further increase the difficulty of passivation. At the same time, the uniformity of the mesa fabrication is also difficult to control, which leads to leakage.

[0004] In planar homojunction technology, indium (In)-doped n-type mercury cadmium telluride (HCdT) is grown on a substrate via liquid-phase epitaxy. The p-region is prepared using As ion implantation. After As ion implantation, the HCdT material requires high-temperature annealing for activation to form a pn junction. However, planar homojunction technology requires arsenic (As) implantation to fabricate the pn junction. Structurally, surface bandgap modulation is not possible, the implanted region has a high defect density, As atom activation requires a complex annealing process with low activation rates, and the annealing process introduces impurity diffusion problems.

[0005] In summary, the two existing process routes for P-on-n type infrared focal plane detectors each have their own advantages and disadvantages and are incompatible. Therefore, it is necessary to improve the existing technologies to further enhance device performance. Summary of the Invention

[0006] To address the issues of leakage caused by material damage, poor passivation layer coverage, and poor interface compactness in existing P-on-n heterojunction processes based on mercury cadmium telluride (MDT) materials, and the numerous problems of thermal damage and impurity diffusion caused by high-temperature annealing in P-on-n planar homojunction processes, this invention provides a P-on-n type MDT pixel-level in-situ grown array detector and its fabrication method.

[0007] The present invention is accomplished through the following technical solution: a P-on-n type mercury cadmium telluride pixel-level in-situ grown array detector, characterized in that it comprises, from bottom to top, a substrate material layer, an n-type absorption layer, a passivation isolation grid layer for isolating pixels, an array P-type cap region located within the isolation grid of the passivation isolation grid layer, a passivation layer covering the passivation isolation grid layer and the array P-type cap region, an electrode contact hole disposed within the array P-type cap region and not covered by the passivation layer, and a contact electrode layer disposed within the electrode contact hole.

[0008] Both the n-type absorber layer and the arrayed p-type cap region are made of Hg. 1-x Cd x Te, where the value of x is less than 1.

[0009] The n-type absorption layer is doped with indium (In), and the indium (In) doping concentration is 1 × 10⁻⁶. 14 cm -3 -5×10 15 cm -3 .

[0010] The passivation isolation mesh layer has a thickness of 500 to 20,000 angstroms, and its materials include, but are not limited to, CdTe, ZnS, SiN, BN, and any combination of these materials.

[0011] The array's P-type cap region is doped with As, and the As doping concentration is 3 × 10⁻⁶.16 cm -3 Up to 5×10 18 cm -3 .

[0012] The thickness of the P-type cap region of the array is 1.0-2.5 μm.

[0013] The method for fabricating a P-on-n type mercury cadmium telluride (HgCd) pixel-level in-situ grown array detector provided by this invention includes the following steps:

[0014] (1) Using Si, GaAs, or cadmium zinc telluride as the substrate material layer, an n-type absorber layer is grown on the substrate material layer by liquid phase epitaxy (LPE). The material of the n-type absorber layer is Hg. 1-x Cd x Te, where x is 0.15-0.4, is used to grow an n-type absorber layer, with indium (In) doping at a concentration of 1 × 10⁻⁶. 14 cm -3 -5×10 15 cm -3 ;

[0015] (2) On the n-type absorption layer in step (1), a passivation layer is prepared by thermal evaporation, magnetron sputtering or MBE process. Then, photolithography is performed on the surface of the passivation layer. After development, the pixel area is exposed. The pixel area is chemically etched to remove the passivation layer and a small part of the n-type absorption layer on the surface of the pixel area. Then, it is immersed in the stripping solution to remove the residual photoresist on the surface, so that a passivation isolation grid layer is formed on the surface. Multiple recessed areas for growing pixels are formed in the passivation isolation grid layer. The thickness of the passivation isolation grid layer is 500 to 20000 angstroms, and the material includes, but is not limited to, one or more of CdTe, ZnS, SiN and BN, and the combination of several is arbitrary.

[0016] (3) On the recessed area of ​​the passivation isolation mesh layer in step (2), an array of P-type Cap regions is prepared by liquid phase epitaxy (LPE) to form an in-situ grown pixel structure, wherein: the thickness of the array of P-type Cap regions is 1.0-2.5 μm, and arsenic (As) is doped during the preparation of the array of P-type Cap regions, with an As doping concentration of 3 × 10⁻⁶. 16 cm -3 Up to 5×10 18 cm -3 This process forms p-type doping and simultaneously creates an amorphous residual region on the surface of the passivation isolation grid layer. The array p-type Cap region material is Hg. 1-x Cd x Te, where x values ​​are 0.3-0.6, and the material Hg in the array P-type Cap region is controlled. 1-x Cd xThe x value of Te is greater than that of the n-type absorber material Hg in step (1). 1-x Cd x The x value of Te;

[0017] (4) Photolithography is performed on the surface of the array P-type Cap region in step (3). After development, the passivation isolation grid layer is exposed. The amorphous residual area on the surface of the passivation isolation grid layer is removed by etching or chemical etching. Then, the resist is removed by cleaning to form a micro mesa structure.

[0018] (5) On the surface of the micro-mesa structure in step (4), a CdTe+ZnS composite passivation layer is prepared by thermal evaporation, magnetron sputtering or MBE and an n-type annealing process is performed, and the thickness of the CdTe+ZnS composite passivation layer is controlled to be 2000-8000 angstroms.

[0019] (6) Photolithography is performed on the surface of the CdTe+ZnS composite passivation layer in step (5) to expose the area corresponding to the first contact hole in the orthogonal projection direction of the P-type Cap region. The CdTe+ZnS composite passivation layer and a small portion of the arrayed P-type Cap region on the surface of the area corresponding to the first contact hole are removed by ICP etching and / or chemical etching to form the first contact hole for which the contact electrode layer needs to be grown.

[0020] (7) Photolithography is performed on the surface of the CdTe+ZnS composite passivation layer in step (6) and around the first contact hole. After development, the second contact hole where the contact electrode layer needs to be grown is exposed.

[0021] (8) Using ion beam sputtering or thermal evaporation, a metal forming a contact electrode layer is grown in the first contact hole and the second contact hole in step (7). The metal is a Cr+Pt+Au three-layer metal to obtain a detector blank.

[0022] (9) Immerse the detector blank from step (8) in the stripping solution to remove the photoresist and the metal on the surface of the photoresist, and obtain a mercury cadmium telluride pixel-level in-situ grown array detector.

[0023] The present invention has the following advantages and effects: By using the above scheme, the mercury cadmium telluride heterojunction material is isolated into independent pixels using a passivated isolation mesh layer, and inter-diffusion at the interface is achieved through the growth process of the P-type Cap region, thereby obtaining a mercury cadmium telluride P-on-n heterojunction detector. Compared with conventional mesa P-on-n heterojunction detectors, it effectively avoids the damage to the mercury cadmium telluride material caused by the mesa fabrication process. At the same time, the micro-mesa surface passivation process reduces leakage current caused by poor coverage of the mesa passivation layer and poor interface compactness. Compared with the existing arsenic (As) injected planar P-on-n homojunction detectors, the heterojunction material structure formed by band modulation reduces interface defects during junction growth, which can effectively suppress tunneling current, reduce dark current, and improve device performance.

[0024] Through experimental comparison, thanks to the natural passivation effect of the surface heterolayer and the band modulation structure, the detector of this invention achieves the dark current level of Rule07 (derived from the empirical formula for dark current of conventional P-on-n detectors) at low temperatures, and the detector response wavelength reaches 13.3 micrometers (77K), with a 10% improvement in process efficiency. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the detector structure of the present invention;

[0026] Figure 2 for Figure 1 Top view;

[0027] Figure 3 This is a pattern of the detector fabricated by the method of the present invention. Detailed Implementation

[0028] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Unless otherwise specified in the embodiments, all processes or technologies are conventional.

[0030] The magnetron sputtering process parameters in the embodiment are as follows: sputtering power 200W, vacuum degree 10mTorr.

[0031] The photolithography process parameters in this embodiment are as follows: spin coating process, with a resist thickness greater than 2 micrometers.

[0032] In the examples, the chemical etchant is HBr + 1% Br2.

[0033] In this example, acetone was used as the stripping fluid.

[0034] The ion beam sputtering process parameters in this embodiment are as follows: sputtering power 300W.

[0035] The n-type annealing process parameters in the embodiment are as follows: temperature is 230℃, time is 48h, and it is carried out in a Hg saturated atmosphere.

[0036] Example 1

[0037] The P-on-n type mercury cadmium telluride pixel-level in-situ grown array detector provided by the present invention includes: a substrate material layer 1, an n-type absorption layer 2, a passivation isolation grid layer 3 for isolating pixels, an array P-type cap region 4 located within the isolation grid of the passivation isolation grid layer 3, a passivation layer 5 covering the passivation isolation grid layer 3 and the array P-type cap region 4, an electrode contact hole disposed within the array P-type cap region 4 and not covered by the passivation layer 5, and a contact electrode layer 6 disposed in the electrode contact hole.

[0038] Both the n-type absorber layer 2 and the arrayed p-type cap region 4 are made of Hg. 1-x Cd x Te, where the value of x is less than 1.

[0039] The n-type absorber layer 2 is doped with indium (In), and the indium (In) doping concentration is 2 × 10⁻⁶. 14 cm -3 n-type absorber layer 2 material Hg 1-x Cd x The value of x in Te is 0.25.

[0040] The passivation isolation mesh layer 3 has a thickness of 3000 angstroms and is made of CdTe.

[0041] The array P-type cap region 4 is doped with As element, and the As element doping concentration is 2×10⁴. 17 cm -3 The material Hg of the array P-type cap region 4 1-x Cd x The value of x in Te is 0.3.

[0042] Example 2

[0043] A method for fabricating a P-on-n type mercury cadmium telluride pixel-level in-situ grown array detector 100 includes the following steps:

[0044] (1): such as Figure 3 Using cadmium zinc telluride as the substrate material layer 1, an n-type absorber layer 2 is grown on the substrate material layer 1 using conventional liquid phase epitaxy (LPE). Indium (In) is doped during the growth of the n-type absorber layer 2 to form n-type doping, with an indium (In) doping concentration of 2 × 10⁻⁶. 14 cm -3 The material of the n-type absorber layer 2 is Hg 1-x Cd x Te, where x is 0.25;

[0045] (2): such as Figure 3In step (1), a passivation layer is prepared on the n-type absorption layer 2 by conventional magnetron sputtering with a sputtering power of 200W and a vacuum degree of 10mTorr. The passivation layer material is CdTe. Then, conventional photolithography is performed on the corresponding part of the passivation layer. After development, the pixel area is exposed. Conventional chemical etching is performed on the pixel area. The chemical etching agent is HBr + 1%Br2 to remove the passivation layer and a small part of the n-type absorption layer on the surface of the photolithographic pixel area. Then, it is immersed in conventional stripping solution for stripping to remove the photoresist on the surface, so that a passivation isolation grid layer 3 is formed on the surface. Two recessed areas 31 for growing pixels are formed in the passivation isolation grid layer 3. The thickness of the passivation isolation grid layer 3 is 3000 angstroms.

[0046] (3): such as Figure 3 In step (2), an array of P-type Cap regions 4 is prepared on the recessed region 31 of the passivation isolation mesh layer 3 using conventional liquid phase epitaxy (LPE) to form an in-situ grown pixel structure. The array of P-type Cap regions 4 has a thickness of 1.5 μm and is doped with arsenic (As) at a concentration of 2 × 10⁻⁶. 17 cm -3 This forms p-type doping, and simultaneously forms an amorphous residual region 7 on the surface of the passivation isolation grid layer 3. The array p-type Cap region 4 is made of Hg. 1-x Cd x Te, where x has a value of 0.3;

[0047] (4): such as Figure 3 In step (3), conventional photolithography is performed on the surface of the array P-type Cap region 4. After development, the passivation isolation mesh layer 3 is exposed. The amorphous residual region 7 on the surface of the passivation isolation mesh layer 3 is removed by conventional chemical etching with HBr + 1% Br2. After cleaning and removing the resist, a micro-mesa structure is formed.

[0048] (5): such as Figure 3 In step (4), a CdTe+ZnS composite passivation layer 5 was prepared on the surface of the micro-mesa structure using conventional magnetron sputtering with a sputtering power of 200W and a vacuum degree of 10mTorr. The thickness of the passivation layer 5 was 3000 angstroms.

[0049] (6): such as Figure 3 In step (5), conventional photolithography is performed on the surface of the CdTe+ZnS composite passivation layer 5. In the corresponding part of the photolithography area, the CdTe+ZnS composite passivation layer 5 and a small part of the array P-type Cap region 4 are removed by ICP etching and chemical etching to form the first contact hole 51 that needs to grow the contact electrode layer 6.

[0050] (7): such as Figure 3In step (6), conventional photolithography is performed on the surface of the CdTe+ZnS composite passivation layer 5 and the periphery of the first contact hole 51. After development, the second contact hole 52 and photoresist 8, which need to grow the contact electrode layer 6, are exposed.

[0051] (8): such as Figure 3 The metal forming the contact electrode layer 6 is grown in the first contact hole 51 in step (6) and the second contact hole 52 in step (7) using a conventional ion beam sputtering process with a sputtering power of 300W. Three layers of metal are used to obtain the detector blank;

[0052] (9): Immerse the detector blank from step (8) in a conventional stripping solution to remove the photoresist 8 and the metal on the surface of the photoresist, obtaining... Figure 1 , 2 The image shows a cadmium telluride mercury pixel-level in-situ growth array detector 100.

[0053] (10) After coupling the detector of step (9) to the silicon readout circuit through flip-chip interconnect process, conventional packaging and testing are performed.

[0054] Example 3

[0055] A method for fabricating a P-on-n type mercury cadmium telluride pixel-level in-situ grown array detector 100 includes the following steps:

[0056] 1): For example Figure 3 Using cadmium zinc telluride as the substrate material layer 1, an n-type absorber layer 2 is grown on the substrate material layer 1 by conventional liquid phase epitaxy (LPE). Indium (In) is doped during the growth of the n-type absorber layer 2 to form n-type doping. The doping concentration of In is 5 × 10⁻⁶. 14 cm -3 The material of the n-type absorber layer 2 is Hg 1-x Cd x Te, where x has a value of 0.3;

[0057] 2): For example Figure 3 In step (1), a passivation layer is prepared on the n-type absorption layer 2 by conventional magnetron sputtering with a sputtering power of 200W and a vacuum degree of 10mTorr. The passivation layer material is CdTe. Then, conventional photolithography is performed on the corresponding part of the passivation layer. After development, the pixel area is exposed. The pixel area is subjected to conventional chemical etching with HBr + 1%Br2 to remove the passivation layer and a small part of the n-type absorption layer on the surface of the photolithographic pixel area. Then, it is immersed in conventional stripping solution to remove the photoresist on the surface, so that a passivation isolation mesh layer 3 is formed on the surface. Two recessed areas 31 for growing pixels are formed in the passivation isolation mesh layer 3. The thickness of the passivation isolation mesh layer 3 is 5000 angstroms.

[0058] 3): For example Figure 3 In step (2), an array of P-type Cap regions 4 is fabricated on the recessed region 31 of the passivation isolation mesh layer 3 using conventional liquid phase epitaxy (LPE) to form an in-situ grown pixel structure. The array of P-type Cap regions 4 has a thickness of 2.0 μm and is doped with arsenic (As) at a concentration of 5 × 10⁻⁶. 17 cm -3 This forms p-type doping, and simultaneously forms an amorphous residual region 7 on the surface of the passivation isolation grid layer 3. The array p-type Cap region 4 is made of Hg. 1-x Cd x Te, where x has a value of 0.35;

[0059] 4): For example Figure 3 In step (3), photolithography is performed on the surface of the array P-type Cap region 4. After development, the passivation isolation mesh layer 3 is exposed. The amorphous residual region 7 on the surface of the passivation isolation mesh layer 3 is removed by conventional chemical etching. After cleaning and removing the resist, a micro-mesa structure is formed.

[0060] 5): For example Figure 3 In step (4), a CdTe+ZnS composite passivation layer 5 was prepared on the surface of the micro-mesa structure using conventional magnetron sputtering. The thickness of the passivation layer 5 was 5000 angstroms.

[0061] 6): For example Figure 3 In step (5), photolithography is performed on the surface of the CdTe+ZnS composite passivation layer 5. In the corresponding part of the photolithography area, the CdTe+ZnS composite passivation layer 5 and a small part of the array P-type Cap region 4 are removed by ICP etching and chemical etching to form the first contact hole 51 that needs to grow the contact electrode layer 6.

[0062] 7): For example Figure 3 In step (6), photolithography is performed on the surface of the CdTe+ZnS composite passivation layer 5 and around the first contact hole 51. After development, the second contact hole 52 and photoresist 8, which need to grow the contact electrode layer 6, are exposed.

[0063] 8): For example Figure 3 The metal forming the contact electrode layer 6 is grown in the first contact hole 51 in step (6) and the second contact hole 52 in step (7) using a conventional ion beam sputtering process with a sputtering power of 300W. Three layers of metal are used to obtain the detector blank;

[0064] 9): Immerse the detector blank from step (8) in a conventional stripping solution to remove the photoresist 8 and the metal on the photoresist surface, obtaining... Figure 1 , 2 The image shows a cadmium telluride mercury pixel-level in-situ growth array detector 100.

[0065] (10) After coupling the detector of step (9) to the silicon readout circuit through flip-chip interconnect process, conventional packaging and testing are performed.

[0066] Example 4

[0067] A method for fabricating a P-on-n type mercury cadmium telluride pixel-level in-situ grown array detector 100 includes the following steps:

[0068] 1): For example Figure 3 Using Si or GaAs as substrate material layer 1, an n-type absorber layer 2 is grown on substrate material layer 1 using conventional liquid phase epitaxy (LPE). Indium (In) is doped during the growth of the n-type absorber layer 2 to form n-type doping, and the doping concentration of In is 3 × 10⁻⁶. 15 cm -3 The material of the n-type absorber layer 2 is Hg 1-x Cd x Te, where x has a value of 0.35;

[0069] 2): For example Figure 3 In step (1), a passivation layer is prepared on the n-type absorption layer 2 by conventional magnetron sputtering with a sputtering power of 200W and a vacuum degree of 10mTorr. Then, photolithography is performed on the corresponding part of the passivation layer. After development, the pixel area is exposed. The pixel area is subjected to conventional chemical etching with HBr + 1%Br2 to remove the passivation layer and a small part of the n-type absorption layer on the surface of the photolithographic pixel area. Then, it is immersed in conventional stripping solution to remove the photoresist on the surface, so that a passivation isolation mesh layer 3 is formed on the surface. Two recessed areas 31 for growing pixels are formed in the passivation isolation mesh layer 3. The thickness of the passivation isolation mesh layer 3 is 8000 angstroms, and the passivation layer material is ZnS.

[0070] 3): For example Figure 3 In step (2), an array of P-type Cap regions 4 is prepared on the recessed region 31 of the passivation isolation mesh layer 3 using conventional liquid phase epitaxy (LPE) to form an in-situ grown pixel structure. The array of P-type Cap regions 4 has a thickness of 2.5 μm and is doped with arsenic (As) at a concentration of 8 × 10⁻⁶. 17 cm -3 This forms p-type doping, and simultaneously forms an amorphous residual region 7 on the surface of the passivation isolation grid layer 3. The array p-type Cap region 4 is made of Hg. 1-x Cd x Te, where x has a value of 0.4;

[0071] 4): For example Figure 3In step (3), photolithography is performed on the surface of the array P-type Cap region 4. After development, the passivation isolation mesh layer 3 is exposed. The amorphous residual region 7 on the surface of the passivation isolation mesh layer 3 is removed by conventional chemical etching with HBr + 1% Br2. After cleaning and removing the resist, a micro-mesa structure is formed.

[0072] 5): For example Figure 3 On the surface of the micro-mesa structure in step (4), a CdTe+ZnS composite passivation layer 5 is prepared by conventional magnetron sputtering. The thickness of the passivation layer 5 is 8000 angstroms.

[0073] 6): For example Figure 3 In step (5), photolithography is performed on the surface of the CdTe+ZnS composite passivation layer 5. In the corresponding part of the photolithography area, the CdTe+ZnS composite passivation layer 5 and a small part of the array P-type Cap region 4 are removed by ICP etching and chemical etching to form the first contact hole 51 that needs to grow the contact electrode layer 6.

[0074] 7): For example Figure 3 In step (6), photolithography is performed on the surface of the CdTe+ZnS composite passivation layer 5 and around the first contact hole 51. After development, the second contact hole 52 and photoresist 8, which need to grow the contact electrode layer 6, are exposed.

[0075] 8): For example Figure 3 The metal forming the contact electrode layer 6 is grown in the first contact hole 51 of step (6) and the second contact hole 52 of step (7) using a conventional ion beam sputtering process. Three layers of metal are used to obtain the detector blank;

[0076] 9): Immerse the detector blank from step (8) in the stripping solution to remove the photoresist 8 and the metal on the surface of the photoresist, obtaining... Figure 1 , 2 The image shows a cadmium telluride mercury pixel-level in-situ growth array detector 100.

[0077] (10) After coupling the detector of step (9) to the silicon readout circuit through flip-chip interconnect process, conventional packaging and testing are performed.

[0078] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0079] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for fabricating a P-on-n type mercury cadmium telluride pixel-level in-situ grown array detector, characterized in that... Includes the following steps: (1) Using Si, GaAs, or cadmium zinc telluride as the substrate material layer, an n-type absorber layer is grown on the substrate material layer by liquid phase epitaxy (LPE). The material of the n-type absorber layer is Hg. 1-x Cd x Te, where x is 0.15-0.4, is used to grow an n-type absorber layer, with indium (In) doping at a concentration of 1 × 10⁻⁶. 14 cm -3 — 5×10 15 cm -3 ; (2) On the n-type absorption layer in step (1), a passivation layer is prepared by thermal evaporation, magnetron sputtering or MBE process. Then, photolithography is performed on the surface of the passivation layer. After development, the pixel area is exposed. The pixel area is chemically etched to remove the passivation layer and a small part of the n-type absorption layer on the surface of the pixel area. Then, it is immersed in the stripping solution to remove the photoresist remaining on the surface, so that a passivation isolation grid layer is formed on the surface. Multiple recessed areas for growing pixels are formed in the passivation isolation grid layer. The thickness of the passivation isolation grid layer is 500~20000 angstroms and the material includes one or more of CdTe, ZnS, SiN and BN. (3) On the recessed area of ​​the passivation isolation grid layer in step (2), an array of P-type Cap regions is prepared by liquid phase epitaxy (LPE) to form an in-situ grown pixel structure, wherein: the thickness of the array of P-type Cap regions is 1.0-2.5 μm, and arsenic (As) elements are doped during the preparation of the array of P-type Cap regions, with an As doping concentration of 3 × 10⁻⁶. 16 cm -3 Up to 5×10 18 cm -3 This process forms p-type doping and simultaneously creates an amorphous residual region on the surface of the passivation isolation grid layer. The array p-type Cap region material is Hg. 1-x Cd x Te, where x values ​​are 0.3-0.6, and the material Hg in the array P-type Cap region is controlled. 1-x Cd x The x value of Te is greater than that of the n-type absorber material Hg in step (1). 1-x Cd x The x value of Te; (4) Photolithography is performed on the surface of the array P-type Cap region in step (3). After development, the passivation isolation grid layer is exposed. The amorphous residual area on the surface of the passivation isolation grid layer is removed by etching or chemical etching. Then, the resist is removed by cleaning to form a micro mesa structure. (5) On the surface of the micro-mesa structure in step (4), a CdTe+ZnS composite passivation layer is prepared by thermal evaporation, magnetron sputtering or MBE, and the thickness of the CdTe+ZnS composite passivation layer is controlled to be 2000~8000 angstroms. (6) Photolithography is performed on the surface of the CdTe+ZnS composite passivation layer in step (5) to expose the area corresponding to the first contact hole in the orthogonal projection direction of the P-type Cap region. The CdTe+ZnS composite passivation layer and a small portion of the arrayed P-type Cap region on the surface of the area corresponding to the first contact hole are removed by ICP etching and / or chemical etching to form the first contact hole for which the contact electrode layer needs to be grown. (7) Photolithography is performed on the surface of the CdTe+ZnS composite passivation layer in step (6) and around the first contact hole. After development, the second contact hole where the contact electrode layer needs to be grown is exposed. (8) Using ion beam sputtering or thermal evaporation, a metal forming a contact electrode layer is grown in the first contact hole and the second contact hole in step (7). The metal is a Cr+Pt+Au three-layer metal to obtain a detector blank. (9) Immerse the detector blank from step (8) in the stripping solution to remove the photoresist and the metal on the surface of the photoresist, and obtain a mercury cadmium telluride pixel-level in-situ grown array detector.

2. The P-on-n type mercury cadmium telluride pixel-level in-situ grown array detector obtained by the preparation method according to claim 1, characterized in that... It includes, from bottom to top, a substrate material layer, an n-type absorption layer, a passivation isolation grid layer for isolating pixels, an array of P-type cap regions located within the isolation grid of the passivation isolation grid layer, a passivation layer covering the passivation isolation grid layer and the array of P-type cap regions, an electrode contact hole disposed within the array of P-type cap regions but not covered by the passivation layer, and a contact electrode layer disposed within the electrode contact hole.

3. The P-on-n type mercury cadmium telluride pixel-level in-situ growth array detector according to claim 2, characterized in that... Both the n-type absorber layer and the arrayed p-type cap region are made of Hg. 1-x Cd x Te, where the value of x is less than 1.

4. The P-on-n type mercury cadmium telluride pixel-level in-situ growth array detector according to claim 2, characterized in that... The n-type absorption layer is doped with indium (In), and the indium (In) doping concentration is 1 × 10⁻⁶. 14 cm -3 — 5×10 15 cm -3 .

5. The P-on-n type mercury cadmium telluride pixel-level in-situ growth array detector according to claim 2, characterized in that... The passivation isolation mesh layer has a thickness of 500~20000 angstroms and its material includes one or more of CdTe, ZnS, SiN, and BN.

6. The P-on-n type mercury cadmium telluride pixel-level in-situ growth array detector according to claim 2, characterized in that... The array's P-type cap region is doped with As, and the As doping concentration is 3 × 10⁻⁶. 16 cm -3 Up to 5×10 18 cm -3 .

7. The P-on-n type mercury cadmium telluride pixel-level in-situ growth array detector according to claim 2, characterized in that... The thickness of the P-type cap region of the array is 1.0-2.5 μm.

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