Preparation method of tellurium-cadmium-mercury infrared detector with controllable arsenic injection dosage
By growing a CdTe sacrificial layer on a mercury cadmium telluride chip and combining it with high-temperature activation treatment, the problems of arsenic ion implantation inhomogeneity and damage were solved, enabling more efficient arsenic implantation dose control and pn junction optimization, thus improving the performance of the infrared detector.
Patent Information
- Application Number
- CN202511201809.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-26
- Publication Date
- 2025-12-16
AI Technical Summary
In the existing technology, the process of arsenic ion implantation into mercury cadmium telluride infrared detectors suffers from damage, uneven implantation, and channeling effects, which lead to increased dark current and poor uniformity of pn junctions.
By growing a CdTe sacrificial layer on a mercury cadmium telluride chip, controlling the arsenic implantation dose, and combining high-temperature activation and passivation layer treatment, the pn junction formation process is optimized, reducing damage and uniformly controlling the implantation dose and depth.
It effectively reduces injection damage, suppresses channeling effects, improves the uniformity of arsenic ion implantation and pn junction performance, reduces dark current, and enhances the overall performance of the detector.
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Figure CN121152364A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of infrared detector, and particularly relates to a preparation method of arsenic injection dose controllable mercury cadmium telluride infrared detection. BACKGROUND
[0002] Mercury cadmium telluride (Hg1-xCdxTe) is the most important material in infrared detectors. Because the forbidden band width of Hg1-xCdxTe can be continuously adjusted in the range of 0-1.6 eV with the change of component x, Hg1-xCdxTe can realize the detection of short wave (1-3 μm), medium wave (3-6 μm), long wave (8-12 μm) and very long wave (12-25 μm) infrared wave bands. The long wave infrared detector of mercury cadmium telluride mainly has n-on-p and p-on-n two types of structure devices. Compared with the n-on-p structure, the p-on-n structure mercury cadmium telluride device has a low-doped n-type absorption region and a low series resistance, and the dark current can be reduced by about 2 orders of magnitude, which is a representative of high R0A value and high performance detector.
[0003] The p-on-n structure mercury cadmium telluride detector mainly has two technical routes of As ion implantation planar junction and As ion in-situ doping mesa junction. Among them, the As ion implantation planar junction is widely used because of its relatively simple and controllable preparation process. The performance of the mercury cadmium telluride p-n junction is closely related to the As injection dose. At present, the method for optimizing the ion injection dose is to carry out process research on different injection doses on the mercury cadmium telluride substrate, and to compare the current-voltage (I-V) curves to select the optimal injection dose. However, this method is easy to cause surface injection damage (defects, displacement atoms, etc.). If the As ions are directly implanted into the HgCdTe, these damages will become carrier recombination centers, reduce the minority carrier lifetime, produce a large dark current, and thus seriously deteriorate the device performance. At the same time, there is an ion channel effect in the process of implanting As ions into HgCdTe, which leads to uneven As implantation and uncontrollable doping concentration. These uneven implantations will form a defect junction region. In the area with a shallow junction depth or serious damage, the electric field is abnormally concentrated, becoming a leakage current channel. And because the breakdown voltages are inconsistent, the weakest point will break down first, and the uniformity of the p-n junction of the device will be poor. SUMMARY
[0004] The embodiment of the present application provides a preparation method of arsenic injection dose controllable mercury cadmium telluride infrared detection, so as to provide a new method for regulating the arsenic injection dose of mercury cadmium telluride, reduce injection damage, inhibit channel effect, uniformly regulate the As ion injection dose and depth, and optimize the p-n junction forming process.
[0005] The embodiment of the present application provides a preparation method of arsenic injection dose controllable mercury cadmium telluride infrared detection, which comprises the following steps: The sacrificial layer is grown on the pretreated HgCdTe chip, which comprises N-type HgCdTe and a substrate, and the sacrificial layer is a CdTe film layer, and the dose of HgCdTe arsenic (As) implantation is regulated based on the CdTe film layer. The HgCdTe chip with the sacrificial layer is subjected to photoetching, and As ions are implanted into the surface of the N-type HgCdTe substrate of the HgCdTe chip. High-temperature activation is performed after the implantation of As ions to realize As activation. A passivation layer is grown on the surface of the HgCdTe chip after the As activation, and the HgCdTe chip is subjected to heat treatment. Photoetching and electrode forming are performed on the surface of the HgCdTe chip after the heat treatment.
[0006] Optionally, the N-type HgCdTe and the substrate are subjected to surface pretreatment to remove organic matters on the surface of the chip.
[0007] Optionally, the growth of the sacrificial layer is realized by using a magnetron sputtering method.
[0008] Optionally, the high-temperature activation after the implantation of As ions comprises forming a P-type doped region at a position corresponding to an ion implantation window in the N-type HgCdTe.
[0009] Optionally, the passivation layer grown on the surface of the HgCdTe chip after the As activation is a ZnS film layer.
[0010] Optionally, the heat treatment process comprises: The HgCdTe chip with the grown passivation layer is placed in a nitrogen annealing furnace to perform high-temperature annealing.
[0011] Optionally, the photoetching and electrode forming on the surface of the HgCdTe chip after the heat treatment comprise: A Cr and Au system electrode is provided, wherein the thickness of the Cr layer is 50-100 nm, and the thickness of the Au layer is 300-500 nm. A HgCdTe p-n junction is prepared.
[0012] Optionally, the HgCdTe chip is subjected to IV testing.
[0013] The embodiments of the present application propose a new method for regulating the dose of HgCdTe arsenic implantation, reducing implantation damage, inhibiting channel effect, uniformly regulating the dose and depth of As ion implantation, and optimizing the p-n junction forming process.
[0014] The above description is only a summary of the technical solutions of the present application, in order to more clearly understand the technical means of the present application, and to be implemented in accordance with the content of the description, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described below. Attached Figure Description
[0015] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a schematic diagram of the basic process for preparing the mercury cadmium telluride infrared detector according to an embodiment of this application; Figure 2 This is a schematic flowchart illustrating the preparation method of the mercury cadmium telluride infrared detector according to an embodiment of this application; Figure 3 This is a schematic diagram of the As-implanted pn junction structure in the fabrication method of the mercury cadmium telluride infrared detector according to an embodiment of this application. Figure 4 Comparison of SIMS curves with and without a sacrificial layer after As implantation, as an example of the fabrication method of mercury cadmium telluride infrared detector in this application embodiment; Figure 5 The above is a comparison of IV curves with and without a sacrificial layer, illustrating an example of the preparation method for the mercury cadmium telluride infrared detector according to an embodiment of this application. Detailed Implementation
[0016] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
[0017] Traditional methods for controlling the As implantation dose involve directly conducting experiments with different As implantation doses on the HCdC chip. However, because As ions bombard the HCdC surface with high energy, they easily cause lattice damage. This implantation damage becomes a generation-recombination center, significantly increasing the device's dark current. Furthermore, HCdC has a zincblende structure, and As is implanted directly along open channels formed by the bulk atomic arrangement, resulting in uncontrollable diffusion distance, concentration, and implantation depth, leading to inhomogeneous implantation. These inhomogeneous implantations form defect junction regions, causing localized electric field concentration, creating leakage channels, generating large dark currents, and leading to pn junction soft breakdown and poor uniformity.
[0018] This application provides a method for preparing a mercury cadmium telluride infrared detector with controllable arsenic injection dosage, such as... Figure 1 As shown, it includes the following steps: In step S101, a sacrificial layer is grown on a pretreated mercury cadmium telluride chip, the mercury cadmium telluride chip comprising an N-type mercury cadmium telluride and a substrate, the sacrificial layer being a CdTe film layer, and the dose of arsenic injection into the mercury cadmium telluride is regulated based on the CdTe film layer. In a specific example, the dose of arsenic injection into the mercury cadmium telluride is regulated by growing the CdTe sacrificial layer. The method of the present application can effectively reduce the damage of high-energy As ions to the surface of the mercury cadmium telluride chip during the injection process, inhibit the channel effect, effectively regulate the As injection dose and depth, and optimize the p-n junction forming process of the mercury cadmium telluride during the subsequent high-temperature activation annealing process, thereby improving the performance of the mercury cadmium telluride p-n junction and reducing the dark current of the device.
[0019] In step S102, the mercury cadmium telluride chip with the sacrificial layer is subjected to photolithography and As ion injection, so that the injected As ions enter the surface of the N-type mercury cadmium telluride substrate; and high-temperature activation is performed after the As ion injection to realize As activation.
[0020] In step S103, a passivation layer is grown on the surface of the mercury cadmium telluride chip after the As activation and the mercury cadmium telluride chip is subjected to heat treatment. In step S104, photolithography and electrode forming are performed on the surface of the mercury cadmium telluride chip after the heat treatment.
[0021] The embodiment of the present application proposes a new method for regulating the dose of arsenic injection into mercury cadmium telluride, reducing injection damage, inhibiting the channel effect, uniformly regulating the dose and depth of As ion injection, and optimizing the p-n junction forming process.
[0022] In some examples, the N-type mercury cadmium telluride and the substrate are also subjected to surface pretreatment to remove organic matter on the surface of the chip. In a specific example, the mercury cadmium telluride chip can be subjected to etching treatment by using an etching liquid to expose a new mercury cadmium telluride surface.
[0023] In some examples, the growth of the sacrificial layer is realized by using a magnetron sputtering method. That is, a CdTe film layer is grown as the sacrificial layer by using the magnetron sputtering method.
[0024] In some examples, the high-temperature activation after the As ion injection comprises forming a P-type doped region in the N-type mercury cadmium telluride at a position corresponding to the ion injection window, as shown in Figure 2
[0025] In some examples, the passivation layer grown on the surface of the mercury cadmium telluride chip after the As activation is a ZnS film layer.
[0026] In some examples, the heat treatment process comprises placing the mercury cadmium telluride chip with the grown passivation layer in a nitrogen annealing furnace for high-temperature annealing.
[0027] In some examples, after the heat treatment, photoetching and electrode forming are performed on the surface of the tellurium cadmium mercury chip, including: A Cr and Au system electrode is provided, wherein the thickness of the Cr layer is 50-100 nm, and the thickness of the Au layer is 300-500 nm. A tellurium cadmium mercury p-n junction is prepared, and a schematic diagram of a tellurium cadmium mercury p-n junction structure is shown as Figure 3 .
[0028] In some examples, the IV test is further performed on the tellurium cadmium mercury chip in step S105. In a specific example, the IV curves of the comparative growth of the sacrificial layer and the non-growth of the sacrificial layer are shown as Figure 4 , 5 .
[0029] Compared with the conventional method of regulating the dose of As ion implantation, the method of regulating the dose of tellurium cadmium mercury arsenic implantation is proposed in the present application. CdTe, as a sacrificial layer, has a very close lattice constant to HgCdTe, can form a high-quality interface with the HgCdTe substrate, has excellent material compatibility, and has excellent thermal stability and can withstand the high temperature generated during the ion implantation process; the CdTe sacrificial layer can reduce the surface damage of the tellurium cadmium mercury; the CdTe sacrificial layer, as an amorphous state, can scatter the As implantation distribution and inhibit the channel effect. The CdTe sacrificial layer regulation method of the present application can reduce the damage to the lattice of tellurium cadmium mercury during the implantation process, reduce the carrier recombination center, improve the minority carrier lifetime, and reduce the dark current of the device. At the same time, it can reduce the channel effect of As ions penetrating along the open channel formed by the atomic arrangement in the tellurium cadmium mercury crystal, so that the implantation dose is controllable, the implantation is more uniform, and the implantation concentration conforms to the Gaussian distribution. The As implantation dose and depth are effectively regulated, and the performance of the tellurium cadmium mercury p-n junction is improved. The method of the present application can optimize the junction forming process of the tellurium cadmium mercury p-n junction after high-temperature activation annealing, and further improve the performance of the detector.
[0030] It should be noted that in the embodiments of the present application, the terms "comprise", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "comprises a" does not exclude the presence of another identical element in the process, method, article or device comprising the element.
[0031] The above-mentioned serial numbers of the embodiments of the present application are only for description, and do not represent the advantages and disadvantages of the embodiments.
[0032] The embodiments of the present application are described above with reference to the accompanying drawings, but the present application is not limited to the specific embodiments described above, and the specific embodiments described above are merely illustrative, but not restrictive, and a person of ordinary skill in the art can make many forms under the inspiration of the present application without departing from the purpose of the present application and the scope protected by the claims, and these all belong to the protection of the present application.
Claims
1. A method for preparing a mercury cadmium telluride infrared detector with controllable arsenic injection dosage, characterized in that, include: A sacrificial layer is grown on a pretreated mercury cadmium telluride (MCH) chip, which includes N-type MCH and a substrate. The sacrificial layer is a CdTe film, and the dosage of MCH and arsenic As implanted is controlled based on the CdTe film. The mercury cadmium telluride chip with the sacrificial layer is photolithographically etched and then implanted with As ions, so that the implanted As ions enter into the surface of the N-type mercury cadmium telluride substrate of the mercury cadmium telluride chip. As activation is achieved by high-temperature activation after As ion implantation; A passivation layer is grown on the surface of the As-activated mercury cadmium telluride chip, followed by heat treatment. Photolithography and electrode forming are performed on the surface of the heat-treated mercury cadmium telluride chip.
2. The preparation method of the arsenic-injection-dosage-controllable mercury cadmium telluride infrared detector as described in claim 1, characterized in that, It also includes surface pretreatment of N-type mercury cadmium telluride to remove organic matter from the chip surface.
3. The preparation method of the arsenic-injection-dosage-controllable mercury cadmium telluride infrared detector as described in claim 1, characterized in that, The sacrificial layer was grown using magnetron sputtering.
4. The preparation method of the arsenic-injection-dosage-controllable mercury cadmium telluride infrared detector as described in claim 1, characterized in that, High-temperature activation after As ion implantation includes forming a P-type doped region at the location corresponding to the ion implantation window within the N-type mercury cadmium telluride.
5. The method for preparing a mercury cadmium telluride infrared detector with controllable arsenic injection dosage as described in claim 1, characterized in that, The passivation layer grown on the surface of the As-activated mercury cadmium telluride chip is a ZnS film.
6. The method for preparing a mercury cadmium telluride infrared detector with controllable arsenic injection dosage as described in claim 5, characterized in that, The heat treatment process includes: The mercury cadmium telluride chip with the passivation layer grown was placed in a nitrogen annealing furnace for high-temperature annealing.
7. The method for preparing a mercury cadmium telluride infrared detector with controllable arsenic injection dosage as described in claim 6, characterized in that, Photolithography and electrode forming are performed on the surface of the heat-treated mercury cadmium telluride chip, including: A Cr and Au system electrode is provided, wherein the thickness of the Cr layer is 50nm to 100nm and the thickness of the Au layer is 300nm to 500nm; Preparation of mercury cadmium telluride pn junction.
8. The method for preparing a mercury cadmium telluride infrared detector with controllable arsenic injection dosage as described in claim 1, characterized in that, It also includes IV testing of the aforementioned mercury cadmium telluride chip.