Infrared detection chip and preparation method thereof

Abstract

The present invention discloses an infrared detection chip and a preparation method thereof, which are applied to the field of infrared detector technology. The chip includes a focal plane array functional layer and a readout circuit, which are combined by a flip-chip interconnection process; the core of the functional layer is an InGaAsSb absorption layer with adjustable components, which can completely cover the short-wave atmospheric window band of 1.0μm to 3.0μm; the functional layer can include AlGaAsSb as a barrier layer to improve device performance; the functional layer needs to be epitaxially grown on a GaSb substrate to ensure growth quality, and then the substrate is removed by a corresponding preparation method to avoid the influence of the GaSb substrate on device performance.

Description

Technical Field

[0001] The present invention relates to the technical field of infrared detectors, and in particular to an infrared detection chip and a method for preparing the infrared detection chip. Background Art

[0002] Infrared detectors are increasingly used at this stage. At present, short-wave infrared detectors are mainly prepared on InP substrates with lattice-matched In 0.53 Ga 0.47 As is used as the absorption layer. The performance of this structure is very good, but the cutoff wavelength is only 1.7μm, which fails to completely cover the short-wave atmospheric window. The solution of increasing the In component in the absorption layer to extend the wavelength has the problem of lattice mismatch, which will lead to a large number of dislocations in the material and a sharp deterioration of the dark current with the wavelength; while using InGaAs / GaAsSb superlattice as the absorption region has the problems of low quantum efficiency and difficulty in growth. Therefore, how to provide a high quantum efficiency infrared detection chip with a wider wavelength range is an urgent problem that technicians in this field need to solve. Summary of the invention

[0003] An object of the present invention is to provide an infrared detection chip having a wider wavelength range; another object of the present invention is to provide a method for preparing an infrared detection chip, and the prepared infrared detection chip has a wider wavelength range.

[0004] In order to solve the above technical problems, the present invention provides an infrared detection chip, comprising a functional layer and a readout circuit;

[0005] The functional layer is formed with mutually separated picture elements to form a focal plane array; the readout circuit is interconnected with the focal plane array;

[0006] The functional layer includes InGaAsSb as an absorption layer. One side of the functional layer has a separation surface formed when a substrate is removed. The substrate is GaSb that matches the absorption layer.

[0007] Optionally, the functional layer includes an etching stop layer, and the separation surface formed after the substrate is corroded is formed on the surface of the etching stop layer.

[0008] Optionally, the corrosion stop layer is InAs 1-x1 Sb x1 , x1=0.09 to 0.12.

[0009] Optionally, the functional layer includes a common electrode layer located between the corrosion stop layer and the absorption layer, and the side of the functional layer facing away from the common electrode layer is interconnected with the readout circuit through flip-chip.

[0010] Optionally, the functional layer includes a contact layer located on a side of the absorption layer facing away from the corrosion stop layer, and the contact layer is interconnected with the readout circuit.

[0011] Optionally, the functional layer includes a common electrode layer located on a side of the absorption layer facing away from the corrosion stop layer, and the side of the functional layer provided with the corrosion stop layer is interconnected with the readout circuit by flip-chip.

[0012] Optionally, a transparent substrate is disposed on the side of the common electrode layer facing away from the functional layer.

[0013] Optionally, an anti-reflection film is arranged between the common electrode layer and the transparent substrate.

[0014] Optionally, the common electrode layer is In x2 Ga 1-x2 As 1-y2 Sb y2 ,x2=0.2 to 0.3,y2=1-0.91x2.

[0015] Optionally, the functional layer includes the absorption layer and a barrier layer located on at least one side of the absorption layer, and the absorption layer is In x3 Ga 1-x3 As 1-y3 Sb y3 , x3 = 0.2 to 0.3, y3 = 1-0.91x3; the barrier layer is Al x4 Ga 1- x4 As 1-y4 Sb, x4=0.2 to 1.0, y4=1-0.08x4.

[0016] The present invention also provides a method for preparing an infrared detection chip, comprising:

[0017] A functional layer is arranged on the surface of the substrate; the functional layer includes InGaAsSb as an absorption layer, and the substrate is GaSb that matches the absorption layer;

[0018] The substrate is removed, a separation surface is formed on one side of the functional layer, and the focal plane array is interconnected with the readout circuit to manufacture an infrared detection chip; the functional layer is formed with mutually separated picture elements to form a focal plane array.

[0019] Optionally, providing a functional layer on the surface of the substrate includes:

[0020] Providing an etching stop layer on the surface of the substrate;

[0021] Disposing the absorption layer on the side of the corrosion stop layer facing away from the substrate;

[0022] The removing of the substrate to form a separation surface on one side of the functional layer comprises:

[0023] The substrate is etched until the etching stop layer is reached, and a separation surface is formed on the surface of the etching stop layer.

[0024] Optionally, providing the functional layer on a side of the corrosion stop layer facing away from the substrate includes:

[0025] Disposing a common electrode layer on a surface of the corrosion stop layer facing away from the substrate;

[0026] The absorption layer is arranged on a side of the common electrode layer facing away from the substrate;

[0027] The substrate is removed, a separation surface is formed on one side of the functional layer, and the focal plane array is interconnected with the readout circuit to make an infrared detection chip including:

[0028] Etching the functional layer from the side of the functional layer facing away from the substrate to the common electrode layer to form the focal plane array;

[0029] interconnecting the focal plane array connected to the substrate and the readout circuit by flip-chip;

[0030] After interconnecting the readout circuits, the substrate is etched down to the etching stop layer to manufacture an infrared detection chip.

[0031] Optionally, providing the absorption layer on a side of the corrosion stop layer facing away from the substrate comprises:

[0032] Disposing the absorption layer on the side of the corrosion stop layer facing away from the substrate;

[0033] Disposing a common electrode layer on the side of the absorption layer facing away from the substrate;

[0034] Disposing a transparent substrate on the side of the common electrode layer facing away from the absorption layer;

[0035] The substrate is removed, a separation surface is formed on one side of the functional layer, and the focal plane array is interconnected with the readout circuit to make an infrared detection chip including:

[0036] Etching the substrate until reaching the etching stop layer;

[0037] Etching the functional layer from the side of the functional layer facing away from the transparent substrate to the common electrode layer to form the focal plane array;

[0038] The focal plane array connected to the transparent substrate is interconnected with the readout circuit by flip-chip to manufacture an infrared detection chip.

[0039] Optionally, providing a transparent substrate on a side of the common electrode layer facing away from the absorption layer includes:

[0040] An anti-reflection film is disposed on the surface of the common electrode layer facing away from the absorption layer;

[0041] A transparent substrate is arranged on the surface of the antireflection film.

[0042] The infrared detection chip provided by the present invention comprises a functional layer and a readout circuit; the functional layer is formed with mutually separated picture elements to form a focal plane array; the readout circuit is interconnected with the focal plane array; the functional layer comprises InGaAsSb as an absorption layer, one side of the functional layer has a separation surface formed when a substrate is removed, and the substrate is GaSb that matches the absorption layer.

[0043] By preparing an InGaAsSb absorption layer on a GaSb substrate, the InGaAsSb absorption layer has a wider detection wavelength range and can cover the complete short-wave atmospheric window band of 1.0μm to 3.0μm; using a GaSb substrate to prepare an InGaAsSb absorption layer and matching the two can maintain lattice matching and high quantum efficiency; and by separating and removing the GaSb substrate, the influence of the GaSb substrate itself absorbing light with a wavelength below 1.7μm can be avoided, thereby ensuring that the detection wavelength range of the infrared detection chip can cover the complete short-wave atmospheric window band.

[0044] The present invention also provides a method for preparing an infrared detection chip, which also has the above-mentioned beneficial effects and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0046] Figure 1 A schematic diagram of the structure of an infrared detection chip provided by an embodiment of the present invention;

[0047] Figure 2 A schematic diagram of the structure of a first specific infrared detection chip provided by an embodiment of the present invention;

[0048] Figure 3 A schematic diagram of the structure of a second specific infrared detection chip provided by an embodiment of the present invention;

[0049] Figure 4 A process flow chart of a method for preparing an infrared detection chip provided by an embodiment of the present invention;

[0050] Figures 5 to 10 A process flow chart of a first specific method for preparing an infrared detection chip provided by an embodiment of the present invention;

[0051] Figures 11 to 15 This is a process flow chart of a second specific method for preparing an infrared detection chip provided in an embodiment of the present invention.

[0052] In the figure: 1. functional layer, 11. absorption layer, 12. barrier layer, 2. readout circuit, 3. substrate, 4. corrosion stop layer, 5. common electrode layer, 6. contact layer, 61. electrode contact layer, 62. ohmic contact layer, 7. transparent substrate, 8. anti-reflection film. DETAILED DESCRIPTION

[0053] The core of the present invention is to provide an infrared detection chip. In the prior art, short-wave infrared detectors are mainly prepared on an InP substrate with matched In 0.53 Ga 0.47 As is used as the absorption layer. The performance of this structure is very good, but the cutoff wavelength is only 1.7μm, which fails to completely cover the short-wave atmospheric window. The solution of increasing the In component in the absorption layer to extend the wavelength has the problem of lattice mismatch, which will lead to a large number of dislocations in the material and a sharp deterioration of dark current with wavelength; while using InGaAs / GaAsSb superlattice as the absorption region has the problems of low quantum efficiency and difficulty in growth.

[0054] The infrared detection chip provided by the present invention has a wider detection wavelength range by preparing an InGaAsSb absorption layer on a GaSb substrate, and the InGaAsSb absorption layer can cover the complete short-wave atmospheric window band of 1.0μm to 3.0μm; the InGaAsSb absorption layer prepared by using a GaSb substrate is matched with each other to maintain lattice matching and high quantum efficiency; and the influence caused by the GaSb substrate itself absorbing light with a wavelength below 1.7μm can be avoided by separating and removing the GaSb substrate, thereby ensuring that the detection wavelength range of the infrared detection chip can cover the complete short-wave atmospheric window band.

[0055] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0056] Please refer to Figure 1 , Figure 1A schematic diagram of the structure of an infrared detection chip provided by an embodiment of the present invention.

[0057] See also Figure 1 In an embodiment of the present invention, the infrared detection chip includes a functional layer 1 and a readout circuit 2; the functional layer 1 is formed with mutually separated pixels to form a focal plane array; the readout circuit 2 is interconnected with the focal plane array; the functional layer 1 includes InGaAsSb as an absorption layer 11, and one side of the functional layer 1 has a separation surface formed when a substrate 3 is removed, and the substrate 3 is GaSb that matches the absorption layer 11.

[0058] The functional layer 1 is mainly an epitaxial structure grown on the substrate 3. The functional layer 1 needs to be formed into mutually separated pixels through processes such as photolithography and etching, and a plurality of pixels will constitute a focal plane array. In this embodiment, the readout circuit 2 is interconnected with the focal plane array, so that the electrical signal generated by each pixel can be read during operation. The specific structure of the readout circuit 2 can refer to the prior art and will not be described in detail here.

[0059] In this embodiment, the functional layer 1 at least needs to include an absorption layer 11, which absorbs light signals of a preset wavelength and generates a corresponding electrical signal, and the above-mentioned readout circuit 2 specifically reads the electrical signal to realize the infrared detection function. In this embodiment, the absorption layer 11 is specifically InGaAsSb. The absorption layer 11 of this material itself corresponds to a very wide detection wavelength range, which can cover the short-wave atmospheric window band of 1.0μm to 3.0μm. The functional layer 1 is specifically grown on a substrate 3 based on GaSb material. There is good matching between InGaAsSb and GaSb, which can ensure that the grown InGaAsSb has good performance and will not cause a decrease in the performance of the infrared detection chip due to a large number of dislocations.

[0060] In this embodiment, one side of the functional layer 1 has a separation surface formed when the substrate 3 is removed, that is, after the functional layer 1 is grown on the surface of the substrate 3, the substrate 3 will be removed, and the separation surface will be formed after the substrate 3 is removed, and the infrared detection chip will not be disturbed by the substrate 3. Because the GaSb substrate 3 absorbs light with a wavelength below 1.7 μm, the removal of the substrate 3 can avoid the influence of the substrate 3 on the absorption band of the infrared detection chip, thereby ensuring that the detection wavelength range of the infrared detection chip can cover the complete short-wave atmospheric window band.

[0061] Specifically, depending on the different separation processes of the substrate 3, the structure of the functional layer 1 will be affected. In a feasible embodiment, the functional layer 1 includes an etching stop layer 4, and the surface of the etching stop layer 4 has the separation surface formed after the substrate 3 is corroded. That is, in this embodiment, the substrate 3 can be removed by an etching process. In order to avoid damaging other structures in the functional layer 1 when the substrate 3 is corroded, it is necessary to set the etching stop layer 4 in the functional layer 1. The etching stop layer 4 needs to have a high selectivity with the substrate 3 to avoid the corrosion of the functional layer 1 by the corrosive liquid when the substrate 3 is corroded. Obviously, in the final infrared detection chip, the separation surface will be specifically formed on the surface of the etching stop layer 4. The above-mentioned etching stop layer 4 can specifically be InAs 1-x1 Sb x1 , x1 = 0.09 to 0.12, and its thickness can be 20nm to 1000nm according to actual needs. Of course, in this embodiment, the specific material of the corrosion stop layer 4 is not specifically limited, depending on the specific situation. It should be noted that if other methods are selected to separate the substrate 3 and the functional layer 1, the above-mentioned corrosion stop layer 4 may not be provided in this embodiment.

[0062] In this embodiment, the entire functional layer 1 generally includes the absorption layer 11 and a barrier layer 12 located on at least one side of the absorption layer 11. The absorption layer 11 is In x3 Ga 1-x3 As 1-y3 Sb y3 , x3 = 0.2 to 0.3, y3 = 1-0.91x3; the barrier layer 12 is Al x4 Ga 1-x4 As 1-y4 Sb, x4=0.2 to 1.0, y4=1-0.08x4.

[0063] The barrier layer 12 may be disposed on only one side of the absorption layer 11, or may be disposed on both sides of the absorption layer 11. In this embodiment, the composition of the absorption layer 11 may be In x3 Ga 1-x3 As 1-y3 Sb y3 , x3 = 0.2 to 0.3, y3 = 1-0.91x3, and its thickness is usually 2000nm to 4000nm; the corresponding barrier layer 12 may specifically be composed of Al x4 Ga 1- x4 As 1-y4Sb, x4=0.2 to 1.0, y4=1-0.08x4, thickness is usually 0nm to 400nm. After barrier layers 12 are provided on both sides of the absorption layer 11, the components of the two barrier layers 12 can be the same or different, as long as they are within the above range, but the respective doping types need to be adjusted accordingly according to the polarity of the device. After appropriate doping, a photovoltaic infrared detection chip containing a pn junction will be formed - if there is no barrier layer, it is similar to a conventional pin structure; if a barrier layer is included, a structure similar to pBin, pBiBn, piBn, etc. can be formed, and the above structure is also extended to include two polarities of "p on n" and "n on p".

[0064] It should be noted that the role of the barrier layer is to improve device performance. In principle, the barrier layer can be absent. The "pn junction" is formed by doping, not directly formed by the barrier layer. However, if there is a barrier layer, it is often chosen to make the "pn junction" inside the barrier layer.

[0065] In the infrared detection chip provided in the present embodiment, an InGaAsSb absorption layer 11 is prepared on a GaSb substrate 3. The InGaAsSb absorption layer 11 has a wider detection wavelength range and can cover the complete short-wave atmospheric window band of 1.0 μm to 3.0 μm. The InGaAsSb absorption layer 11 is prepared using a GaSb substrate 3 and the two are matched with each other to maintain lattice matching and high quantum efficiency. By separating and removing the GaSb substrate 3, the influence caused by the GaSb substrate 3 itself absorbing light with a wavelength below 1.7 μm can be avoided, thereby ensuring that the detection wavelength range of the infrared detection chip can cover the complete short-wave atmospheric window band.

[0066] The specific structure of the infrared detection chip provided by the present invention will be described in detail in the following invention embodiments.

[0067] Embodiment 2

[0068] Please refer to Figure 2 , Figure 2 This is a schematic structural diagram of a first specific infrared detection chip provided by an embodiment of the present invention.

[0069] Different from the above-mentioned invention embodiment, the present invention embodiment further defines the structure of the infrared detection chip on the basis of the above-mentioned invention embodiment. The rest of the contents have been described in detail in the above-mentioned invention embodiment and will not be repeated here.

[0070] See also Figure 2 In the embodiment of the present invention, the functional layer 1 includes a common electrode layer 5 located between the corrosion stop layer 4 and the absorption layer 11, and the side of the functional layer 1 facing away from the common electrode layer 5 is interconnected with the readout circuit 2 by flip-chip.

[0071] In the present embodiment, the common electrode layer 5 is specifically located between the corrosion stop layer 4 and the absorption layer 11. When the side of the absorption layer 11 facing the corrosion stop layer 4 is the barrier layer 12, the common electrode layer 5 can be in contact with the barrier layer 12; when the barrier layer 12 is not provided, the common electrode layer 5 can be in contact with the absorption layer 11. In the present embodiment, pixels are specifically split from the functional layer 1 on the side facing away from the common electrode layer 5 to form a focal plane array. When the functional layer 1 is split, its cutoff position is usually the common electrode layer 5, that is, the common electrode layer 5 will span multiple pixels of the focal plane array as a common electrode. Correspondingly, in the present embodiment, the side of the functional layer 1 facing away from the common electrode layer 5 is specifically interconnected with the readout circuit 2. In the present embodiment, the common electrode layer 5 is In x2 Ga 1-x2 As 1-y2 Sb y2 , x2 = 0.2 to 0.3, y2 = 1-0.91x2, and its thickness is usually 200nm to 1000nm. Of course, in this embodiment, other components of the common electrode layer 5 can also be used, and the specific components are not specifically limited here.

[0072] Furthermore, in this embodiment, the functional layer 1 may include a contact layer 6 located on the side of the absorption layer 11 facing away from the corrosion stop layer 4, and the contact layer 6 is interconnected with the readout circuit 2. When the side of the absorption layer 11 facing the contact layer 6 is a barrier layer 12, the contact layer 6 may be in contact with the barrier layer 12; when the barrier layer 12 is not provided, the contact layer 6 may be in contact with the absorption layer 11.

[0073] The contact layer 6 is mainly used to reduce the contact resistance between the readout circuit 2 and the functional layer 1. In this embodiment, the contact layer 6 may include an electrode contact layer 61 and an ohmic contact layer 62. The electrode contact layer 61 is located on the side of the absorption layer 11 facing away from the common electrode layer 5, and the ohmic contact layer 62 is located on the surface of the electrode contact layer 61 facing away from the common electrode layer 5. The electrode contact layer 61 may be In x5 Ga 1-x5 As 1-y5 Sb y5,x5=0.2~0.3,y5=1-0.91x, and its thickness is usually 200nm~1000nm. The ohmic contact layer 62 can be InAs or GaSb, which is used to achieve ohmic contact when in contact with the readout circuit 2. The thickness of the ohmic contact layer 62 is usually thin. Of course, in this embodiment, the ohmic contact layer 62 may not be provided, and only the above-mentioned electrode contact layer 61 may be provided, depending on the actual situation, and no specific limitation is made here. Of course, the above-mentioned contact layer 6 usually needs to be divided into an image element array structure, that is, the above-mentioned contact layer 6 can be provided on the side of each pixel facing away from the common electrode layer 5. In this embodiment, when the ohmic contact layer 62 is provided, the readout circuit 2 will specifically contact the ohmic contact layer 62; when the ohmic contact layer 62 is not provided, the readout circuit 2 can directly contact the electrode contact layer 61.

[0074] In the infrared detection chip provided in this embodiment, the side where the functional layer 1 is interconnected with the readout circuit 2 and the side where the functional layer 1 is separated from the substrate 3 are located on opposite sides, so that the preparation process of the infrared detection chip is simple and the structural complexity is low.

[0075] The specific structure of the infrared detection chip provided by the present invention will be described in detail in the following invention embodiments.

[0076] Embodiment 3

[0077] Please refer to Figure 3 , Figure 3 This is a schematic structural diagram of a second specific infrared detection chip provided in an embodiment of the present invention.

[0078] Different from the above-mentioned invention embodiment, the present invention embodiment further defines the structure of the infrared detection chip on the basis of the above-mentioned invention embodiment. The rest of the contents have been described in detail in the above-mentioned invention embodiment and will not be repeated here.

[0079] See also Figure 3 In the embodiment of the present invention, the functional layer 1 includes a common electrode layer 5 disposed on the side of the absorption layer 11 facing away from the corrosion stop layer 4, and the side of the functional layer 1 on which the corrosion stop layer 4 is disposed is interconnected with the readout circuit 2 by flip-chip.

[0080] In this embodiment, the corrosion stop layer 4 and the common electrode layer 5 are arranged on opposite sides of the absorption layer 11. Similar to the above embodiment, in this embodiment, the pixels are segmented from the functional layer 1 on the side facing away from the common electrode layer 5 to form a focal plane array. When the functional layer 1 is segmented, the cut-off position is usually the common electrode layer 5. In this embodiment, the common electrode layer 5 is In x2 Ga 1-x2 As 1-y2 Sby2 , x2 = 0.2 to 0.3, y2 = 1-0.91x2, and its thickness is usually 200nm to 1000nm. Of course, in this embodiment, other components of the common electrode layer 5 can also be used, and the specific components are not specifically limited here.

[0081] Correspondingly, in this embodiment, the functional layer 1 is etched from the corrosion stop layer 4 to form a pixel, and at this time, the absorption layer 11 is specifically connected to the readout circuit 2 through the corrosion stop layer 4. The advantage of setting the structure in this way is that the corrosion stop layer 4 can be avoided from being set in the optical path of the absorption layer 11 absorbing light, that is, the interference caused by the corrosion stop layer 4 absorbing light of a specific wavelength can be avoided. Correspondingly, in this embodiment, the corrosion stop layer 4 can also be used as a contact layer 6 to reduce the contact resistance between the functional layer 1 and the readout circuit 2. In this embodiment, the corrosion stop layer 4 that acts as the contact layer 6 can be made of InAs. 1-x1 Sb x1 , x1=0.09 to 0.12, and its thickness is usually 200nm to 1000nm. Of course, in this embodiment, the material of the etching stop layer 4 is not specifically limited, and it depends on the specific situation.

[0082] Specifically, in this embodiment, a transparent substrate 7 is provided on the side of the common electrode layer 5 facing away from the functional layer 1. In order to realize the connection of the readout circuit 2 on the side of the functional layer 1 where the substrate 3 is removed, it is necessary to ensure that there is a substrate to support the functional layer 1 before the substrate 3 is removed and the functional layer 1 is interconnected with the readout circuit 2. Therefore, in this embodiment, a transparent substrate 7 can be further provided on the side of the common electrode layer 5 facing away from the absorption layer 11 to provide the above-mentioned support. It should be noted that the transparent substrate 7 is specifically transparent to the detection band corresponding to the infrared detection chip provided in this embodiment, rather than transparent to the visible light range. That is, the light of the detection band corresponding to the absorption layer 11 in this embodiment can be transmitted to the absorption layer 11 through the above-mentioned transparent substrate 7, and will not be absorbed by the transparent substrate 7. When bonding the functional layer 1 to the transparent substrate 7, the transparent substrate 7 can be specifically pasted on one side of the functional layer 1 using transparent glue. Obviously, the transparent glue is also specifically transparent to the detection band corresponding to the infrared detection chip provided in this embodiment, rather than transparent to the visible light range. That is, the light in the detection band corresponding to the absorption layer 11 in this embodiment can be transmitted through the transparent glue to the absorption layer 11 without being absorbed by the transparent glue.

[0083] Furthermore, in this embodiment, an anti-reflection film 8 may be further provided between the common electrode layer 5 and the transparent substrate 7. The anti-reflection film 8 may increase the amount of light transmitted to the absorption layer 11 to improve the performance of the infrared detection chip. Of course, the anti-reflection film 8 may not be provided based on cost, depending on the specific situation, and is not specifically limited here.

[0084] In the infrared detection chip provided by this embodiment, the functional layer 1 is interconnected with the readout circuit 2 through the corrosion stop layer 4, so as to avoid the corrosion stop layer 4 from absorbing light, thereby further improving the performance of the infrared detection chip.

[0085] Embodiment 4

[0086] A method for preparing an infrared detection chip provided in an embodiment of the present invention is introduced below. The preparation method described below and the infrared detection chip described above can be referred to each other.

[0087] Please refer to Figure 4 , Figure 4 A process flow chart of a method for preparing an infrared detection chip provided in an embodiment of the present invention.

[0088] See also Figure 4 In an embodiment of the present invention, a method for preparing an infrared detection chip includes:

[0089] S101: Disposing a functional layer on the surface of a substrate.

[0090] In this embodiment, the functional layer 1 includes InGaAsSb as the absorption layer 11, and the substrate 3 is GaSb that matches the absorption layer 11. The structure of the functional layer 1 has been described in detail in the above-mentioned invention embodiment, and will not be repeated here. The various film layers of the above-mentioned functional layer 1 are usually prepared by epitaxial growth, and the specific process can be referred to the prior art, and will not be repeated here.

[0091] In order to facilitate the feasibility of subsequent separation of the substrate 3, this step generally specifically includes: setting an etching stop layer 4 on the surface of the substrate 3; setting the absorption layer 11 on the side of the etching stop layer 4 facing away from the substrate 3; that is, first setting the etching stop layer 4, and then setting the functional layer 1. The structure of the etching stop layer 4 has been described in detail in the above-mentioned embodiment of the invention, and will not be repeated here. The purpose of setting the etching stop layer 4 in this step is to achieve the removal of the substrate 3 by etching in the subsequent steps.

[0092] S102: removing the substrate, forming a separation surface on one side of the functional layer, and interconnecting the focal plane array with the readout circuit to form an infrared detection chip.

[0093] In this embodiment, the functional layer 1 is formed with mutually separated picture elements to form a focal plane array. The specific structure of the focal plane array has been described in detail in the above invention embodiments, and will not be repeated here.

[0094] There is no clear order between the above-mentioned process of removing the substrate 3 and the process of etching the functional layer 1 to form a separation surface, and the specific contents will be described in detail in the following invention embodiments. The above-mentioned process of removing the substrate 3 may specifically include: corroding the substrate 3 to the end of the corrosion stop layer 4, so that the surface of the corrosion stop layer 4 serves as the separation surface. That is, in this step, the substrate 3 can be removed by corrosion, and the end position of the process is the corrosion stop layer 4, so a separation surface will be formed on the surface of the corrosion stop layer 4. Of course, if the thickness of the substrate 3 is too thick, the substrate 3 can be removed by thinning the substrate 3 first and then etching the substrate 3. The process of thinning the substrate 3 can be thinned by cutting, grinding and polishing, etc. The specific process of thinning the substrate 3 can refer to the prior art and will not be repeated here.

[0095] A method for preparing an infrared detection chip provided in an embodiment of the present invention comprises preparing an InGaAsSb absorption layer 11 on a GaSb substrate 3, wherein the InGaAsSb absorption layer 11 has a wider detection wavelength range and can cover the complete short-wave atmospheric window band of 1.0 μm to 3.0 μm; using a GaSb substrate 3 to prepare the InGaAsSb absorption layer 11 and matching the two can maintain lattice matching and high quantum efficiency; and separating and removing the GaSb substrate 3 can avoid the influence caused by the GaSb substrate 3 itself absorbing light with a wavelength below 1.7 μm, thereby ensuring that the detection wavelength range of the infrared detection chip can cover the complete short-wave atmospheric window band.

[0096] The specific structure of the method for preparing an infrared detection chip provided by the present invention will be described in detail in the following invention embodiments.

[0097] Embodiment 5

[0098] Please refer to Figures 5 to 10 , Figures 5 to 10 This is a process flow chart of a first specific method for preparing an infrared detection chip provided in an embodiment of the present invention.

[0099] The preparation method provided in this embodiment corresponds to the infrared detection chip structure corresponding to the above-mentioned embodiment 2. Figure 5 In this embodiment, the method for preparing the infrared detection chip includes:

[0100] S201: Setting an etching stop layer on the substrate surface.

[0101] See also Figure 6 The specific content of this step has been described in detail in the above-mentioned embodiment of the invention and will not be repeated here.

[0102] S202: Disposing a common electrode layer on the surface of the etching stop layer facing away from the substrate.

[0103] See also Figure 7 In this step, a common electrode layer 5 can be provided on the surface of the corrosion stop layer 4 through an epitaxial growth process. The specific contents of the common electrode layer 5 have been described in detail in the above-mentioned embodiments of the invention and will not be repeated here.

[0104] S203: Disposing an absorption layer on the side of the common electrode layer facing away from the substrate.

[0105] See also Figure 8 In this step, specifically, an absorption layer 11 is disposed on the side of the common electrode layer 5 facing away from the substrate 3. At this time, the film layers disposed in sequence along the thickness direction on the surface of the substrate 3 are the corrosion stop layer 4, the common electrode layer 5, and the absorption layer 11. In this embodiment, a barrier layer 12 may be disposed between the absorption layer 11 and the common electrode layer 5. After this step, a contact layer 6 may be further disposed on the side of the absorption layer 11 facing away from the substrate 3. The specific structure of the contact layer 6 has been described in detail in the above-mentioned invention embodiment, and will not be repeated here.

[0106] S204: etching the functional layer from the side of the functional layer facing away from the substrate to the common electrode layer to form a focal plane array.

[0107] See also Fig. 9 In this step, the functional layer 1 is etched before removing the substrate 3. The etching process may include photolithography, etching process, passivation and other processes to form separated pixels and form a focal plane array. The cutoff position of the above etching is usually the common electrode layer 5, and the etching process needs to at least pass through the absorption layer 11.

[0108] S205: interconnecting the focal plane array connected to the substrate with the readout circuit by flip-chip.

[0109] See also Fig.10 In this step, before removing the substrate 3, the side of the functional layer 1 not provided with the substrate 3 is interconnected with the readout circuit 2 through a flip-chip process. The specific contents of the flip-chip process can be referred to the prior art, and will not be described in detail here.

[0110] S206: After interconnecting the readout circuits, the substrate is etched down to the etching stop layer to manufacture an infrared detection chip.

[0111] See also Figure 2 After the readout circuit 2 is interconnected, the present embodiment will eventually etch the substrate 3, and the cut-off position is the etching stop layer 4 to manufacture an infrared detection chip. If the substrate 3 is thick, the substrate 3 can be thinned first, and then etched to quickly remove the substrate 3.

[0112] The method for preparing an infrared detection chip provided in this embodiment can ensure that the functional layer 1 is always supported by a structure by first bonding the functional layer 1 to the readout circuit 2 and then removing the substrate 3, so as to ensure that the functional layer 1 is not easily damaged during preparation and ensure that the infrared detection chip has good performance.

[0113] The specific structure of the method for preparing an infrared detection chip provided by the present invention will be described in detail in the following invention embodiments.

[0114] Embodiment 6

[0115] Please refer to Figures 11 to 15 , Figures 11 to 15 This is a process flow chart of a second specific method for preparing an infrared detection chip provided in an embodiment of the present invention.

[0116] The preparation method provided in this embodiment corresponds to the infrared detection chip structure corresponding to the above-mentioned embodiment 3. Fig.11 In this embodiment, the method for preparing the infrared detection chip includes:

[0117] S301: Setting an etching stop layer on the substrate surface.

[0118] This step is basically the same as S201 in the above-mentioned embodiment of the invention. Please refer to the above-mentioned embodiment of the invention for details, and will not be described again here.

[0119] S302: Disposing an absorption layer on the side of the etching stop layer facing away from the substrate.

[0120] S303: Disposing a common electrode layer on the side of the absorption layer facing away from the substrate.

[0121] See also Fig.12 In this embodiment, specifically, the absorption layer 11 is firstly arranged on the side of the corrosion stop layer 4 facing away from the substrate 3, and then the common electrode layer 5 is arranged on the side of the absorption layer 11 facing away from the substrate 3, so as to ensure that the corrosion stop layer 4 and the common electrode layer 5 are located on both sides of the functional layer 1. In this embodiment, a barrier layer 12 may be arranged between the corrosion stop layer 4 and the absorption layer 11, and a barrier layer 12 may also be arranged between the common electrode layer 5 and the absorption layer 11.

[0122] S304: Disposing a transparent substrate on the side of the common electrode layer facing away from the absorption layer.

[0123] See also Fig.13In this step, a transparent substrate 7 is disposed on the side of the common electrode layer 5 facing away from the substrate 3. The specific contents of the transparent substrate 7 have been described in detail in the above-mentioned embodiments of the invention, and will not be repeated here. The transparent substrate 7 is used to provide support for the functional layer 1 before interconnecting with the readout circuit 2 after the substrate 3 is removed. The functional layer 1 and the transparent substrate 7 can be connected by bonding the functional layer 1 and the transparent substrate 7 with transparent glue.

[0124] Specifically, this step may include: providing an anti-reflection film 8 on the surface of the common electrode layer 5 facing away from the absorption layer 11; and providing a transparent substrate 7 on the surface of the anti-reflection film 8. In order to further improve the performance of the infrared detection chip and allow more light to enter the absorption layer 11, in this step, the anti-reflection film 8 may be provided on the surface of the common electrode layer 5 first, and then the transparent substrate 7 may be provided on the surface of the anti-reflection film 8, so as to increase the total amount of light entering the absorption layer 11 through the anti-reflection film 8. The thickness of the anti-reflection film 8 usually corresponds to the absorption wavelength of the absorption layer 11, and its specific thickness needs to be determined according to actual conditions.

[0125] S305: Etching the substrate until the etching stop layer is reached.

[0126] See also Fig.14 In this step, the substrate 3 needs to be corroded after the transparent base 7 is set, so as to ensure that there is always at least one layer of structure that can provide support for the functional layer 1.

[0127] S306: etching the functional layer from the side of the functional layer facing away from the transparent substrate to the common electrode layer to form a focal plane array.

[0128] See also Fig.15 Different from the above embodiment, the present embodiment specifically removes the substrate 3 to form a separation surface first, and then etches the functional layer 1 on the separation surface, that is, from the etching stop layer 4, to form a focal plane array, and the end position of the etching process is located at the common electrode layer 5. For the specific contents of the above etching, please refer to the above invention embodiment, which will not be repeated here.

[0129] S307: interconnecting the focal plane array connected to the transparent substrate with the readout circuit by flip-chip to produce an infrared detection chip.

[0130] See also Figure 3 The specific process of the above interconnection can refer to the prior art. In this embodiment, the structure makes the light path entering the absorption layer 11 not pass through the corrosion stop layer 4, but pass through the transparent substrate 7, the anti-reflection film 8, and the barrier layer 12 in sequence to reach the absorption layer 11. Therefore, the corrosion stop layer 4 will not affect the light absorption of the absorption layer 11. In this embodiment, the corrosion stop layer 4 not only serves as the cut-off position of the corrosion, but also serves as the contact layer 6 to interconnect with the readout circuit 2.

[0131] In the method for preparing an infrared detection chip provided in this embodiment, the functional layer 1 is interconnected with the readout circuit 2 through the etching stop layer 4, thereby avoiding the absorption of light by the etching stop layer 4, thereby further improving the performance of the infrared detection chip.

[0132] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other. Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements that are not clearly listed, or also includes elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements limited by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements.

[0133] The above is a detailed introduction to an infrared detection chip and a preparation method thereof provided by the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. An infrared detection chip, characterized in that: It comprises a functional layer (1) and a readout circuit (2); The functional layer (1) is formed with mutually separated picture elements to form a focal plane array; the readout circuit (2) is interconnected with the focal plane array; The functional layer (1) comprises InGaAsSb as an absorption layer (11), one side of the functional layer (1) has a separation surface formed when a substrate (3) is removed, and the substrate (3) is GaSb that matches the absorption layer (11); The functional layer (1) comprises an etching stop layer (4), and the surface of the etching stop layer (4) is provided with the separation surface formed after etching the substrate (3); The functional layer (1) comprises a common electrode layer (5) located on the side of the absorption layer (11) facing away from the corrosion stop layer (4); the corrosion stop layer (4) is used as a contact layer (6); the side of the functional layer (1) provided with the corrosion stop layer (4) is interconnected with the readout circuit (2) by flip-chip, so as to prevent the corrosion stop layer (4) from being arranged in the optical path of the absorption layer (11) absorbing light; A transparent substrate (7) is provided on the side of the common electrode layer (5) facing away from the functional layer (1); the functional layer (1) is etched from the side of the functional layer (1) facing away from the transparent substrate (7) to the common electrode layer (5), so as to form the focal plane array; and an anti-reflection film (8) is provided between the common electrode layer (5) and the transparent substrate (7).

2. The infrared detection chip according to claim 1, characterized in that: The corrosion stop layer (4) is InAs 1- x1 Sb x1 , x1=0.09 to 0.

12.

3. The infrared detection chip according to claim 1 or 2, characterized in that: The common electrode layer (5) is In x2 Ga 1-x2 As 1-y2 Sb y2 ,x2=0.2 to 0.3,y2=1-0.91x2.

4. The infrared detection chip according to claim 1, characterized in that: The functional layer (1) comprises the absorption layer (11) and a barrier layer (12) located on at least one side surface of the absorption layer (11), wherein the absorption layer (11) is In x3 Ga 1- x3 As 1-y3 Sb y3 , x3 = 0.2 to 0.3, y3 = 1-0.91x3; the barrier layer (12) is Al x4 Ga 1-x4 As 1-y4 Sb, x4=0.2 to 1.0, y4=1-0.08x4.

5. A method for preparing an infrared detection chip, characterized in that: include: A functional layer (1) is arranged on the surface of a substrate (3); the functional layer (1) comprises InGaAsSb as an absorption layer (11), and the substrate (3) is GaSb that matches the absorption layer (11); The substrate (3) is removed, a separation surface is formed on one side of the functional layer (1), and the focal plane array is interconnected with the readout circuit (2) to manufacture an infrared detection chip; The functional layer (1) is formed with mutually separated picture elements to form a focal plane array; Providing a functional layer (1) on the surface of a substrate (3) comprises: Providing an etching stop layer (4) on the surface of the substrate (3); The absorption layer (11) is arranged on the side of the corrosion stop layer (4) facing away from the substrate (3); The removing of the substrate (3) and forming a separation surface on one side of the functional layer (1) comprises: Etching the substrate (3) until reaching the etching stop layer (4), and forming a separation surface on the surface of the etching stop layer (4); Providing the absorption layer (11) on the side of the corrosion stop layer (4) facing away from the substrate (3) comprises: The absorption layer (11) is arranged on the side of the corrosion stop layer (4) facing away from the substrate (3); A common electrode layer (5) is provided on the side of the absorption layer (11) facing away from the substrate (3); A transparent substrate (7) is arranged on the side of the common electrode layer (5) facing away from the absorption layer (11); The substrate (3) is removed, a separation surface is formed on one side of the functional layer (1), and the focal plane array is interconnected with the readout circuit (2) to manufacture an infrared detection chip comprising: Etching the substrate (3) until reaching the etching stop layer (4); The functional layer (1) is etched from the side of the functional layer (1) facing away from the transparent substrate (7) to the common electrode layer (5), so as to form the focal plane array; the etching stop layer (4) is used as a contact layer (6); The focal plane array connected to the transparent substrate (7) is interconnected with the readout circuit (2) by flip-chip to manufacture an infrared detection chip, thereby preventing the corrosion stop layer (4) from being arranged in the optical path of the light absorbed by the absorption layer (11); The transparent substrate (7) is arranged on the side of the common electrode layer (5) facing away from the absorption layer (11), comprising: An anti-reflection film (8) is provided on the surface of the common electrode layer (5) on the side facing away from the absorption layer (11); A transparent substrate (7) is arranged on the surface of the anti-reflection film (8).

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