Infrared detector passivation method for suppressing surface leakage current and infrared detector

Abstract

This invention provides an infrared detector passivation method and an infrared detector capable of suppressing surface leakage current. The passivation method includes the following steps: When a dielectric passivation layer is formed on the surface of the epitaxial layer of the infrared detector, an equivalent charge is introduced on the side of the dielectric passivation layer near the surface of the epitaxial layer. The polarity of the equivalent charge is the same as the polarity of the charge in the non-flat-band carrier layer formed on the surface of the epitaxial layer. The Coulomb electrostatic force between the equivalent charge of the dielectric passivation layer and the non-flat-band carrier layer charge is used to modulate the surface energy band of the epitaxial layer, bringing the surface energy band into a flat-band state, thereby suppressing surface leakage current. This invention, by designing the dielectric passivation layer to contain charge and achieving surface energy band state modulation through Coulomb electrostatic force, achieves the same flat-band effect as metal gate modulation without the need for a metal gate or the application of additional voltage. This avoids the problems introduced by metal gates in detector array and readout circuit design, greatly reducing the design and manufacturing difficulty of infrared focal plane arrays.

Description

Technical Field

[0001] This invention belongs to the field of infrared detector technology, specifically relating to an infrared detector passivation method that can suppress surface leakage current and an infrared detector. Background Technology

[0002] When the chemical bonds between atoms in an infrared detector break at the surface, defect energy levels are formed. These defect energy levels cause the energy band to bend at the surface, resulting in the surface being in an inversion, depletion, or accumulation state. Surface inversion leads to severe tunneling and leakage currents, while surface depletion introduces severe recombination currents. Both of these situations will increase the dark current of the device and degrade its performance.

[0003] Existing infrared detectors suppress surface leakage current by constructing a gate-controlled diode using a metal gate on the surface of a dielectric passivation layer. The gate voltage can modulate the carrier concentration on the detector surface through the electric field effect, thereby controlling the surface band state of the infrared detector. When an appropriate voltage is applied to the gate, the surface can be in a flat band state, at which point the surface leakage current of the infrared detector can be completely suppressed. However, while using a gate-controlled diode can suppress the surface leakage current of an infrared detector, there are two major technical challenges in applying this technology to the fabrication of focal plane arrays of infrared detectors: The first is the fabrication of small-pixel infrared detector arrays containing metal gates. The fabrication of the metal gate and the electrode lead-out in such small-pixel arrays increase the number of process steps. In addition, the electrical insulation between the metal gate and the positive and negative electrodes of the diode also faces challenges. The second is the design of the readout circuit that matches the gate-controlled diode array. The readout circuit needs to provide a voltage bias to the gate, which increases the circuit design difficulty and power consumption. Summary of the Invention

[0004] The purpose of this invention is to provide a passivation method for infrared detectors that can suppress surface leakage current, which can at least solve some of the defects existing in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A passivation method for an infrared detector that can suppress surface leakage current includes the following process:

[0007] When a dielectric passivation layer is formed on the surface of the epitaxial layer of an infrared detector, an equivalent charge is introduced on the side of the dielectric passivation layer near the surface of the epitaxial layer. The polarity of the equivalent charge is the same as the polarity of the charge in the non-flat carrier layer formed on the surface of the epitaxial layer. The Coulomb electrostatic force between the equivalent charge of the dielectric passivation layer and the charge in the non-flat carrier layer is used to regulate the surface energy band of the epitaxial layer, so that the surface energy band is in a flat band state, thereby suppressing surface leakage current.

[0008] Furthermore, the dielectric passivation layer is composed of at least two dielectric materials, with a dielectric interface formed between each pair of adjacent dielectric materials, and an electric dipole formed at at least a portion of the dielectric interface, through which the equivalent charge is generated on the surface of the dielectric passivation layer near the non-flat carrier layer.

[0009] Furthermore, the opposite charges of the electric dipoles are respectively confined within the corresponding two dielectric materials.

[0010] Furthermore, the dielectric passivation layer includes one or more sets of periodically stacked dielectric layer pairs, each set of dielectric layer pairs including a first dielectric layer and a second dielectric layer grown in a stack, and the electric dipole is formed between the first dielectric layer and the second dielectric layer. By changing the material type of the first dielectric layer and the second dielectric layer or the deposition order of the first dielectric layer and the second dielectric layer on the epitaxial layer, the polarity of the equivalent charge generated by the electric dipole is controlled so that the polarity of the equivalent charge is the same as that of the non-flat band carrier layer charge.

[0011] Furthermore, in each pair of dielectric layers, the first dielectric layer is disposed close to the surface of the epitaxial layer, and the second dielectric layer is deposited on the first dielectric layer;

[0012] When the charge polarity at the surface of the epitaxial layer is negative, the first dielectric layer is a SiO2 thin film and the second dielectric layer is a HfO2 thin film.

[0013] When the charge polarity at the surface of the epitaxial layer is positive, the first dielectric layer is an HfO2 thin film and the second dielectric layer is a SiO2 thin film; or the first dielectric layer is a SiO2 thin film and the second dielectric layer is a La2O3 thin film.

[0014] Furthermore, the non-flat carrier layer is an inversion layer formed by inversion on the surface of the epitaxial layer, or a depletion layer formed by depletion on the surface of the epitaxial layer, or an accumulation layer formed by accumulation on the surface of the epitaxial layer.

[0015] In addition, the present invention also provides an infrared detector, including a substrate, an epitaxial layer, a dielectric passivation layer, a first metal electrode, and a second metal electrode. The epitaxial layer is disposed on the substrate, and the dielectric passivation layer covers the surface of the epitaxial layer. The dielectric passivation layer has an equivalent charge with the same polarity as the non-flat carrier layer charge on the surface of the epitaxial layer. The surface energy band of the epitaxial layer is modulated by the Coulomb electrostatic force between the equivalent charge of the dielectric passivation layer and the non-flat carrier layer charge, so that the surface energy band is in a flat band state. The first metal electrode and the second metal electrode are grown on the epitaxial layer. The dielectric passivation layer is provided with a first electrode window and a second electrode window, and the first metal electrode and the second metal electrode are respectively located in the first electrode window and the second electrode window.

[0016] Furthermore, the dielectric passivation layer includes one or more sets of periodically stacked dielectric layer pairs, each set of dielectric layer pairs including a first dielectric layer and a second dielectric layer. In each set of dielectric layer pairs, the first dielectric layer is disposed close to the surface of the epitaxial layer, and the second dielectric layer is disposed on the first dielectric layer. The interface between the first dielectric layer and the second dielectric layer forms an electric dipole, and the electric dipole generates the equivalent charge on the surface of the dielectric passivation layer close to the non-flat carrier layer.

[0017] Furthermore, the thickness of both the first dielectric layer and the second dielectric layer is 1-100 nm.

[0018] Furthermore, the epitaxial layer includes a buffer layer, a lower contact layer, an infrared absorption layer, and an upper contact layer stacked sequentially from bottom to top. The infrared absorption layer and the upper contact layer form a frustum structure. The first electrode window is located on the lower contact layer, and the second electrode window is located on the upper contact layer.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] (1) This invention designs the dielectric passivation layer to contain charges, and achieves surface band state control through Coulomb electrostatic force. It does not require a metal gate or additional voltage, and can achieve the same flat band effect as metal gate control. It avoids the problems introduced by metal gate in the design of detector array and readout circuit, and greatly reduces the design and manufacturing difficulty of infrared focal plane array.

[0021] (2) The present invention utilizes the design of generating near-surface controllable equivalent charge by the dielectric interface electric dipole, so that the dielectric passivation layer contains charge, and its charge polarity can be flexibly adjusted. It can be adapted to N-type / P-type infrared detectors and different material systems, and has a wide range of applications and strong scalability.

[0022] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the infrared detector in an embodiment of the present invention;

[0024] Figure 2 This is a schematic diagram of the structure in which the surface of the epitaxial layer is in an inverted state in an embodiment of the present invention;

[0025] Figure 3 This is one embodiment of the invention that introduces charge into the dielectric passivation layer;

[0026] Figure 4 This is a schematic diagram of the equivalent charge polarity control method of the dielectric passivation layer in an embodiment of the present invention.

[0027] Explanation of reference numerals in the attached figures: 1. Substrate; 2. Buffer layer; 3. Lower contact layer; 4. First metal electrode; 5. Non-flat carrier layer; 6. Infrared absorption layer; 7. Dielectric passivation layer; 8. Upper contact layer; 9. Second metal electrode; 71. First dielectric layer; 72. Second dielectric layer. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the 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] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection", and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, an abutting connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature; in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0032] Example 1:

[0033] like Figure 1 As shown, this embodiment provides a passivation method for an infrared detector that can suppress surface leakage current, including the following process:

[0034] When a dielectric passivation layer 7 is formed on the surface of the epitaxial layer of the infrared detector, an equivalent charge is introduced on the side of the dielectric passivation layer 7 near the surface of the epitaxial layer. The polarity of the equivalent charge is the same as the polarity of the charge in the non-flat carrier layer 5 formed on the surface of the epitaxial layer. The Coulomb electrostatic force between the equivalent charge of the dielectric passivation layer 7 and the charge in the non-flat carrier layer 5 is used to regulate the surface energy band of the epitaxial layer, so that the surface energy band is in a flat band state, thereby suppressing surface leakage current.

[0035] Specifically, in infrared detector semiconductors (i.e., epitaxial layers), defect energy levels are formed at the surface / sidewalls due to the breaking of atomic chemical bonds, causing surface band bending and resulting in three states: inversion, depletion, or accumulation. Therefore, the non-flat band carrier layer 5 formed on the epitaxial layer surface can be an inversion layer formed by surface inversion, a depletion layer formed by surface depletion, or an accumulation layer formed by surface accumulation. For different types of infrared detectors, the charge polarity of the non-flat band carrier layer 5 varies under these different states. For example, in the case of surface inversion in a P-type epitaxial layer, the surface inversion layer is composed of electrons and exhibits a negative charge polarity; in the case of surface inversion in an N-type epitaxial layer, the surface inversion layer is composed of holes and exhibits a positive charge polarity; and in the case of surface depletion in a P-type epitaxial layer, the surface depletion layer is composed of ionized acceptors and exhibits a negative charge polarity. When the surface of an N-type epitaxial layer is depleted, its depletion layer is composed of ionized donors and exhibits a positive charge polarity. When the surface of a P-type epitaxial layer is accumulated, its accumulation layer is composed of holes and exhibits a positive charge polarity. When the surface of an N-type epitaxial layer is accumulated, its accumulation layer is composed of electrons and exhibits a negative charge polarity. Of course, the charge polarity of the non-flat band carrier layer 5 can also be determined by actual measurement of the surface of the epitaxial layer of the infrared detector. Therefore, for different charge polarities of the non-flat band carrier layer 5, an equivalent charge of the corresponding polarity can be introduced into the dielectric passivation layer 7 near the surface of the epitaxial layer, so that it generates a Coulomb electrostatic force with the charge of the non-flat band carrier layer 5, thereby repelling the charge of the non-flat band carrier layer 5, thereby controlling the surface energy band of the epitaxial layer, restoring the surface energy band to a stable flat band state, and suppressing the above-mentioned surface leakage currents from the root.

[0036] One specific implementation of introducing equivalent charge into the dielectric passivation layer 7 is to design the dielectric passivation layer 7 to be stacked with at least two dielectric materials, forming a dielectric interface between each pair of adjacent dielectric materials. At least a portion of the dielectric interface forms an electric dipole. The electric dipole generates an equivalent charge with controllable polarity and intensity on the surface of the near-non-flat carrier layer 5. This is because the distance between the different dielectric materials and the surface of the epitaxial layer is different. The electrostatic effect of the charge on the surface is significantly stronger on the side closer to the epitaxial layer than that on the side farther away. This makes the electric dipole as a whole present a net charge of a single polarity near the surface of the epitaxial layer, i.e., the equivalent charge. The polarity and intensity of this equivalent charge can be controlled by selecting the dielectric materials and designing the deposition process (i.e., sequence, thickness, etc.). By using the equivalent charge generated by the electric dipole at the dielectric interface, the surface energy band of the epitaxial layer can be controlled, precisely pulling its surface from the inversion / depletion / accumulation state back to the flat band state, and suppressing various surface leakage currents.

[0037] In one embodiment, such as Figure 3 As shown, the dielectric passivation layer 7 adopts a double-layer composite structure, including a first dielectric layer 71 and a second dielectric layer 72 stacked together. The first dielectric layer 71 and the second dielectric layer 72 are insulating dielectrics of different materials, and the interface between them forms the electric dipole. By changing the material types of the first dielectric layer 71 and the second dielectric layer 72 or the deposition order of the two on the epitaxial layer, the polarity of the equivalent charge generated by the electric dipole can be controlled so that the polarity of the equivalent charge is the same as the polarity of the charge of the non-flat band carrier layer 5. The intensity of the equivalent charge can be controlled by designing the thickness of the first dielectric layer 71 and the second dielectric layer 72.

[0038] Furthermore, since the deposition thickness of the single-layer first dielectric layer 71 and the second dielectric layer 72 is limited, the equivalent charge intensity that can be regulated is also limited. In order to increase the range of regulation of the equivalent charge intensity, the first dielectric layer 71 and the second dielectric layer 72 can be regarded as a pair of dielectric layers and multiple pairs of dielectric layers can be stacked and grown sequentially on the surface of the epitaxial layer. Each pair of dielectric layers generates an electric dipole. The stacking of multiple pairs of dielectric layers can make the equivalent charges generated by each pair of dielectric layers superimpose in the same direction, significantly improving the total equivalent charge intensity and regulation capability. This enables wide-range, high-precision, and high-stability regulation of the energy band of the semiconductor surface, ensuring that the surface in different regions can reach the ideal flat band state, and suppressing surface leakage current from the root.

[0039] This method is applicable to various cooled infrared detectors where surface energy bands affect surface leakage current, including mesa-type and planar-type infrared detectors, with absorption layers including mercury cadmium telluride, indium telluride, type II superlattices, quantum wells, etc.

[0040] This embodiment uses a p-type InAs / GaSb type-II superlattice as an example of an infrared absorption layer. Because the periodic structure of the p-type infrared absorption layer material breaks at the sidewalls, the resulting dangling bonds cause the surface bands to bend, resulting in inversion. Figure 2 As shown, the electron concentration of the inversion layer on the surface of the P-type infrared absorption layer is usually very high (black dots in the figure represent electrons), exhibiting negative charge polarity. In this case, the materials of the two dielectric layers of the dielectric passivation layer 7 can be a combination of SiO2 thin film and HfO2 thin film. Since an electric dipole is formed at the interface between the SiO2 thin film and the HfO2 thin film, as... Figure 4 As shown in (a), the SiO2 film exhibits a negative charge, and the HfO2 film exhibits a positive charge. Therefore, the SiO2 film is used as the first dielectric layer 71 and is placed close to the sidewall surface of the epitaxial layer. The HfO2 film is grown on the SiO2 film and is far away from the sidewall surface of the epitaxial layer. As a result, the equivalent charge generated by the electric dipole formed at the interface between the two is a negative charge, which is the same as the charge polarity of the inversion layer on the surface of the P-type infrared absorption layer. This generates a Coulomb electrostatic force, which repels the electrons in the inversion layer, thereby suppressing the surface leakage current caused by inversion on the sidewall surface of the epitaxial layer.

[0041] In some embodiments, when the charge polarity of the non-flat carrier layer 5 on the epitaxial layer surface is positive (such as the inversion of the N-type infrared absorption layer), the order of the SiO2 film and the HfO2 film can be reversed. That is, the first dielectric layer 71 (near the sidewall surface of the epitaxial layer) uses an HfO2 film, and the second dielectric layer 72 (away from the sidewall surface of the epitaxial layer) uses a SiO2 film. Figure 4 As shown in (b), since the HfO2 thin film is closer to the sidewall of the epitaxial layer, the equivalent charge generated by the electric dipole it forms is positive, thus generating a Coulomb repulsion force with the positive charge of the non-flat carrier layer 5; in addition, the dielectric passivation layer 7 can also be selected from two other dielectric materials in combination, such as the first dielectric layer 71 using a SiO2 thin film and the second dielectric layer 72 using a La2O3 thin film, such as... Figure 4 As shown in (c), when an electric dipole is formed at the interface, the SiO2 film is positively charged and the La2O3 film is negatively charged. At this time, when the SiO2 film is brought closer to the sidewall of the epitaxial layer, the equivalent charge generated by the electric dipole is positive, which can also generate Coulomb repulsion with the positive charge of the non-flat carrier layer 5.

[0042] In this embodiment, the electric dipole is formed by interfacial charge transfer caused by the difference in electron affinity, dielectric constant or chemical bond state between the first dielectric layer 71 and the second dielectric layer 72. Thus, the equivalent charge generated is a fixed static charge that does not drift, ionize or change with bias voltage. Therefore, the purpose of surface flat band control can be achieved without an external gate or external bias voltage.

[0043] In an optimized design, the opposite charges of the electric dipole are confined within two corresponding dielectric materials. Specifically, for a two-layer stacked structure, the opposite charges of the electric dipole are confined within the first dielectric layer 71 and the second dielectric layer 72, achieving strict spatial separation of opposite charges. This ensures that the near-surface charge control effect is maximized while the far-side charge effect is shielded / weakened, guaranteeing high stability of the polarity and intensity of the near-surface equivalent charge. It also prevents the neutralization or polarity reversal of opposite charges, ensuring repeatable and predictable control effects. Specifically, strict spatial separation of opposite charges in the electric dipole can be achieved by selecting two heterogeneous insulating dielectrics with significantly different electron affinities as the first dielectric layer 71 and the second dielectric layer 72. Alternatively, an atomically steep interface can be prepared using an in-situ clean growth process. Furthermore, the thickness of the first dielectric layer 71 and the second dielectric layer 72 can be controlled, or a combination of these methods can be used synergistically.

[0044] Example 2:

[0045] like Figure 1 As shown, this embodiment provides an infrared detector, including a substrate 1, an epitaxial layer, a dielectric passivation layer 7, a first metal electrode 4, and a second metal electrode 9. The epitaxial layer is disposed on the substrate 1, and the dielectric passivation layer 7 covers the surface of the epitaxial layer. The dielectric passivation layer 7 has an equivalent charge with the same polarity as the non-flat carrier layer 5 of the epitaxial layer. The first metal electrode 4 and the second metal electrode 9 are grown on the epitaxial layer. The dielectric passivation layer 7 has a first electrode window and a second electrode window, and the first metal electrode 4 and the second metal electrode 9 are respectively located within the first electrode window and the second electrode window. In this embodiment, the surface energy band of the epitaxial layer is modulated by the Coulomb electrostatic force between the equivalent charge of the dielectric passivation layer 7 and the charge of the non-flat carrier layer 5, so that the surface energy band is in a flat band state, thereby suppressing surface leakage current.

[0046] In one specific embodiment, the dielectric passivation layer 7 includes one or more sets of periodically stacked dielectric layer pairs. Each set of dielectric layer pairs includes a first dielectric layer 71 and a second dielectric layer 72. In each set of dielectric layer pairs, the first dielectric layer 71 is disposed closer to the surface of the epitaxial layer, and the second dielectric layer 72 is disposed on the first dielectric layer 71. The interface between the first dielectric layer 71 and the second dielectric layer 72 forms an electric dipole. The electric dipole generates the equivalent charge on the dielectric passivation layer 7 near the surface of the non-flat carrier layer 5. The polarity of the equivalent charge can be controlled by changing the material types of the first dielectric layer 71 and the second dielectric layer 72 or their deposition order on the epitaxial layer. At the same time, the intensity of the equivalent charge can be controlled by designing the thickness of the first dielectric layer 71 and the second dielectric layer 72. Optionally, the thickness of the first dielectric layer 71 and the second dielectric layer 72 is 1-100 nm, preferably the thickness of the first dielectric layer is less than or equal to the thickness of the second dielectric layer. The total intensity of the equivalent charge of the dielectric passivation layer 7 can also be controlled by designing the number of dielectric layer pairs.

[0047] Taking a P-type InAs / GaSb type-II superlattice as the absorption region NonP mesa infrared detector as an example, its epitaxial layer includes a buffer layer 2, a lower contact layer 3, an infrared absorption layer 6, and an upper contact layer 8 stacked sequentially from bottom to top on a substrate 1. The infrared absorption layer 6 and the upper contact layer 8 form a mesa structure. The first electrode window is located on the lower contact layer 3, and the second electrode window is located on the upper contact layer 8. The inversion layer generated on the surface of the epitaxial layer has a negative charge. Therefore, the first dielectric layer 71 is designed to be a SiO2 thin film, and the second dielectric layer 72 is designed to be a HfO2 thin film.

[0048] The above examples are merely illustrative of the present invention and do not constitute a limitation on the scope of protection of the present invention. All designs that are the same as or similar to the present invention are within the scope of protection of the present invention.

Claims

1. A passivation method for infrared detectors capable of suppressing surface leakage current, characterized in that, The process includes the following: When a dielectric passivation layer is formed on the surface of the epitaxial layer of an infrared detector, an equivalent charge is introduced on the side of the dielectric passivation layer near the surface of the epitaxial layer. The polarity of the equivalent charge is the same as the polarity of the charge in the non-flat carrier layer formed on the surface of the epitaxial layer. The Coulomb electrostatic force between the equivalent charge of the dielectric passivation layer and the charge in the non-flat carrier layer is used to regulate the surface energy band of the epitaxial layer, so that the surface energy band is in a flat band state, thereby suppressing surface leakage current.

2. The infrared detector passivation method as described in claim 1, characterized in that: The dielectric passivation layer is composed of at least two dielectric materials, with a dielectric interface formed between each pair of adjacent dielectric materials. An electric dipole is formed at at least a portion of the dielectric interface, and the equivalent charge is generated on the surface of the dielectric passivation layer near the non-flat carrier layer through the electric dipole.

3. The infrared detector passivation method as described in claim 2, characterized in that: The opposite charges of the electric dipoles are respectively confined within the corresponding two dielectric materials.

4. The infrared detector passivation method as described in claim 2, characterized in that: The dielectric passivation layer includes one or more sets of periodically stacked dielectric layer pairs. Each set of dielectric layer pairs includes a first dielectric layer and a second dielectric layer grown in a stack. The electric dipole is formed between the first dielectric layer and the second dielectric layer. By changing the material type of the first dielectric layer and the second dielectric layer or the deposition order of the first dielectric layer and the second dielectric layer on the epitaxial layer, the polarity of the equivalent charge generated by the electric dipole is controlled so that the polarity of the equivalent charge is the same as that of the non-flat band carrier layer charge.

5. The infrared detector passivation method as described in claim 4, characterized in that: In each pair of dielectric layers, the first dielectric layer is disposed close to the surface of the epitaxial layer, and the second dielectric layer is deposited on the first dielectric layer; When the charge polarity at the surface of the epitaxial layer is negative, the first dielectric layer is a SiO2 thin film and the second dielectric layer is a HfO2 thin film. When the charge polarity at the surface of the epitaxial layer is positive, the first dielectric layer is an HfO2 thin film and the second dielectric layer is a SiO2 thin film; or the first dielectric layer is a SiO2 thin film and the second dielectric layer is a La2O3 thin film.

6. The infrared detector passivation method as described in claim 1, characterized in that: The non-flat carrier layer is an inversion layer formed by inversion on the surface of the epitaxial layer, or a depletion layer formed by depletion on the surface of the epitaxial layer, or an accumulation layer formed by accumulation on the surface of the epitaxial layer.

7. An infrared detector, characterized in that: The device includes a substrate, an epitaxial layer, a dielectric passivation layer, a first metal electrode, and a second metal electrode. The epitaxial layer is disposed on the substrate, and the dielectric passivation layer covers the surface of the epitaxial layer. The dielectric passivation layer has an equivalent charge with the same polarity as the non-flat carrier layer charge on the surface of the epitaxial layer. The surface energy band of the epitaxial layer is modulated by the Coulomb electrostatic force between the equivalent charge of the dielectric passivation layer and the non-flat carrier layer charge, so that the surface energy band is in a flat band state. The first metal electrode and the second metal electrode are grown on the epitaxial layer. The dielectric passivation layer has a first electrode window and a second electrode window, and the first metal electrode and the second metal electrode are respectively located in the first electrode window and the second electrode window.

8. The infrared detector as described in claim 7, characterized in that: The dielectric passivation layer includes one or more sets of periodically stacked dielectric layer pairs. Each set of dielectric layer pairs includes a first dielectric layer and a second dielectric layer. In each set of dielectric layer pairs, the first dielectric layer is disposed close to the surface of the epitaxial layer, and the second dielectric layer is disposed on the first dielectric layer. The interface between the first dielectric layer and the second dielectric layer forms an electric dipole. The electric dipole generates the equivalent charge on the surface of the dielectric passivation layer close to the surface of the non-flat carrier layer.

9. The infrared detector as described in claim 8, characterized in that: The thickness of both the first dielectric layer and the second dielectric layer is 1-100 nm.

10. The infrared detector as described in claim 7, characterized in that: The epitaxial layer includes a buffer layer, a lower contact layer, an infrared absorption layer, and an upper contact layer stacked sequentially from bottom to top. The infrared absorption layer and the upper contact layer form a frustum structure. The first electrode window is located on the lower contact layer, and the second electrode window is located on the upper contact layer.

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