Three-waveband image sensor and manufacturing method thereof

Abstract

The invention belongs to the technical field of semiconductor technology, and discloses a three-waveband image sensor and a manufacturing method thereof, the image sensor comprises a substrate layer, a silicon oxide layer, an aluminum oxide layer, a first electrode layer, an ultraviolet light sensing layer, a visible light sensing layer, an infrared light sensing layer, a second electrode layer and a passivation layer which are stacked in sequence; a plurality of rectangular grooves which have the same shape and are distributed at preset intervals penetrate through the second electrode layer, the infrared light sensing layer, the visible light sensing layer and the ultraviolet light sensing layer in sequence; the ultraviolet light sensing layer is made of an intrinsic aluminum arsenide material; the visible light sensing layer is made of an intrinsic gallium arsenide material; the infrared light sensing layer is made of germanium materials which are obliquely cut by 6 degrees in intrinsic mode. The passivation layer uniformly covers the second electrode layer and the inner wall of each rectangular groove; according to the invention, the problems of lattice mismatch and polarity mismatch among three sensing layers in the prior art can be solved, the manufacturing cost is reduced, and the method is suitable for batch production.

Description

Technical Field

[0001] The present application relates to the field of semiconductor process technology, and in particular to a three-band image sensor and a manufacturing method thereof. Background Art

[0002] The UV-visible-shortwave infrared image sensor has the characteristics of wide spectral sensitivity. The spectral response range can cover the ultraviolet band (100-400nm), visible light band (380-750nm) and shortwave infrared band (1000-2500nm). It has multifunctional imaging capabilities and provides strong support for the widespread application and development of wide-spectrum imaging technology.

[0003] The mainstream ultraviolet light sensing layer, visible light sensing layer and short-wave infrared light sensing layer respectively use wide bandgap semiconductor materials (such as GaN, SiC, Ga2O3, ZnO, etc.), Si semiconductor materials and narrow bandgap semiconductor materials (such as InGaAs, PbS, SnS, etc.), but there is a huge lattice mismatch between the three, and the InGaAs / InP structure technology also has the problems of fragile InP wafers, small wafer size and high raw material cost. Summary of the invention

[0004] The present application provides a three-band image sensor and a manufacturing method thereof, which can solve the lattice mismatch and polarity mismatch problems between the three sensing layers in the prior art, reduce the manufacturing cost, and is suitable for mass production.

[0005] In a first aspect, an embodiment of the present application provides a three-band image sensor, including:

[0006] N-type electrode, P-type electrode and readout circuit, and sequentially stacked substrate layer, silicon oxide layer, aluminum oxide layer, first electrode layer, ultraviolet light sensing layer, visible light sensing layer, infrared light sensing layer, second electrode layer and passivation layer;

[0007] A plurality of rectangular grooves of the same shape and distributed at preset intervals sequentially penetrate the second electrode layer, the infrared light sensing layer, the visible light sensing layer and the ultraviolet light sensing layer; the ultraviolet light sensing layer adopts an intrinsic aluminum arsenide material; the visible light sensing layer adopts an intrinsic gallium arsenide material; the infrared light sensing layer adopts an intrinsic germanium material with a 6-degree bevel;

[0008] The passivation layer uniformly covers the second electrode layer and the inner walls of each rectangular groove;

[0009] The N-type electrode is arranged in the rectangular groove and passes through the passivation layer to connect the first electrode layer; the P-type electrode passes through the passivation layer to connect the second electrode layer; and the readout circuit is respectively connected to the N-type electrode and the P-type electrode.

[0010] Furthermore, the substrate layer is a glass substrate or a sapphire substrate; and the thickness of the silicon oxide layer is between 10 nanometers and 100 nanometers.

[0011] Furthermore, the first electrode layer is a P-type aluminum arsenide electrode layer with a 6-degree bevel; the second electrode layer is an N-type germanium electrode layer with a 6-degree bevel; or the first electrode layer is an N-type aluminum arsenide electrode layer with a 6-degree bevel; the second electrode layer is a P-type germanium electrode layer with a 6-degree bevel.

[0012] Further, the thickness of the aluminum oxide layer is 10 nanometers;

[0013] The thickness of the first electrode layer and the second electrode layer are both between 100 nanometers and 500 nanometers.

[0014] Furthermore, the thickness of the ultraviolet light sensing layer is between 100 nanometers and 500 nanometers; the thickness of the visible light sensing layer is between 100 nanometers and 1000 nanometers; and the thickness of the infrared light sensing layer is between 500 nanometers and 3000 nanometers.

[0015] Furthermore, the germanium-based materials used in the infrared light sensing layer include germanium-tin alloy, germanium quantum well, germanium-silicon quantum well, germanium-tin quantum well or silicon-germanium-tin quantum well.

[0016] In a second aspect, an embodiment of the present application provides a method for manufacturing a three-band image sensor, comprising:

[0017] Providing a silicon substrate with a 6-degree bevel cut; sequentially stacking a germanium buffer layer with a 6-degree bevel cut, a second electrode layer, an infrared light sensing layer, a visible light sensing layer, an ultraviolet light sensing layer, a first electrode layer and an aluminum oxide layer on the silicon substrate to obtain a donor substrate;

[0018] Among them, the ultraviolet light sensing layer uses intrinsic aluminum arsenide material; the visible light sensing layer uses intrinsic gallium arsenide material; the infrared light sensing layer uses intrinsic germanium material with a 6-degree bevel;

[0019] Providing a substrate layer; stacking a silicon oxide layer on the substrate layer to obtain an acceptor substrate;

[0020] Wafer bonding the donor substrate and the acceptor substrate;

[0021] removing the silicon substrate and the germanium buffer layer to obtain a sensor wafer;

[0022] A plurality of rectangular grooves of the same shape and distributed at preset intervals are arranged on the sensor wafer; the rectangular grooves sequentially penetrate the second electrode layer, the infrared light sensing layer, the visible light sensing layer and the ultraviolet light sensing layer;

[0023] A passivation layer, an N-type electrode and a P-type electrode are provided, and the N-type electrode and the P-type electrode are connected to a readout circuit.

[0024] Furthermore, the above-mentioned removal of the silicon substrate and the germanium buffer layer to obtain a sensor wafer includes:

[0025] The silicon substrate and the germanium buffer layer are removed by back thinning, wet etching, dry etching or chemical mechanical polishing.

[0026] In a third aspect, an embodiment of the present application provides a three-band image sensor, including:

[0027] N-type electrode, P-type electrode and readout circuit, and sequentially stacked substrate layer, silicon oxide layer, aluminum oxide layer, first electrode layer, ultraviolet light sensing layer, visible light sensing layer, infrared light sensing layer, second electrode layer and passivation layer;

[0028] A plurality of rectangular grooves of the same shape and distributed at preset intervals sequentially penetrate the infrared light sensing layer, the visible light sensing layer and the ultraviolet light sensing layer; the second electrode layer is located between two adjacent rectangular grooves, embedded in the infrared light sensing layer and has a length less than the preset interval;

[0029] The ultraviolet light sensing layer adopts intrinsic aluminum arsenide material; the visible light sensing layer adopts intrinsic gallium arsenide material; the infrared light sensing layer adopts germanium material with an intrinsic bevel of 6 degrees; the passivation layer evenly covers the second electrode layer and the inner wall of each rectangular groove;

[0030] The N-type electrode is arranged in the rectangular groove and passes through the passivation layer to connect the first electrode layer; the P-type electrode passes through the passivation layer to connect the second electrode layer; and the readout circuit is respectively connected to the N-type electrode and the P-type electrode.

[0031] In a fourth aspect, an embodiment of the present application provides a method for manufacturing a three-band image sensor, comprising:

[0032] Providing a silicon substrate with a 6-degree bevel cut; sequentially stacking a germanium buffer layer with a 6-degree bevel cut, an infrared light sensing layer, a visible light sensing layer, an ultraviolet light sensing layer, a first electrode layer and an aluminum oxide layer on the silicon substrate to obtain a donor substrate;

[0033] Among them, the ultraviolet light sensing layer uses intrinsic aluminum arsenide material; the visible light sensing layer uses intrinsic gallium arsenide material; the infrared light sensing layer uses intrinsic germanium material with a 6-degree bevel;

[0034] Providing a substrate layer; stacking a silicon oxide layer on the substrate layer to obtain an acceptor substrate;

[0035] Wafer bonding the donor substrate and the acceptor substrate;

[0036] removing the silicon substrate and the germanium buffer layer to obtain a sensor wafer;

[0037] forming a plurality of second electrode layers on the infrared light sensing layer by ion implantation;

[0038] A plurality of rectangular grooves of the same shape and distributed at preset intervals are arranged on the sensor wafer; the rectangular grooves sequentially penetrate the infrared light sensing layer, the visible light sensing layer and the ultraviolet light sensing layer; the second electrode layer is located between two adjacent rectangular grooves, embedded in the infrared light sensing layer and has a length less than the preset interval;

[0039] A passivation layer, an N-type electrode and a P-type electrode are provided, and the N-type electrode and the P-type electrode are connected to a readout circuit.

[0040] In summary, compared with the prior art, the technical solution provided in the embodiment of the present application has at least the following beneficial effects:

[0041] The present application provides a three-band image sensor, wherein the ultraviolet light sensing layer is made of intrinsic aluminum arsenide material, the visible light sensing layer is made of intrinsic gallium arsenide material, and the infrared light sensing layer is made of intrinsic germanium material with a 6-degree bevel. The lattice constants of these three semiconductor materials are respectively and The lattice is extremely matched, which solves the lattice mismatch and polarity mismatch problems between the three sensing layers in the prior art; in addition, compared with InGaAs, PbS, and SnS short-wave infrared photoelectric materials, the epitaxial process of aluminum arsenide, gallium arsenide, and germanium materials of the present application is stable and simple, with high product yield and lower manufacturing cost, and is suitable for mass production of image sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A structural diagram of a mesa-type triple-band image sensor provided as an exemplary embodiment of the present application.

[0043] Figure 2 A schematic diagram of wafer bonding operation steps provided for an exemplary embodiment of the present application.

[0044] Figure 3 A rendering of a rectangular groove forming step provided for an exemplary embodiment of the present application.

[0045] Figure 4 A schematic diagram of a mesa-type image sensor connected to a readout circuit according to an exemplary embodiment of the present application.

[0046] Figure 5 A structural diagram of a planar three-band image sensor provided by an exemplary embodiment of the present application.

[0047] Figure 6 This is a diagram showing the effect of forming a second electrode layer by ion implantation according to an exemplary embodiment of the present application.

[0048] Figure 7 A schematic diagram of a planar image sensor connected to a readout circuit according to an exemplary embodiment of the present application.

[0049] Description of reference numerals:

[0050] 001, silicon substrate; 002, germanium buffer layer; 101, substrate layer; 102, silicon oxide layer; 103, aluminum oxide layer; 104, first electrode layer; 105, ultraviolet light sensing layer; 106, visible light sensing layer; 107, infrared light sensing layer; 108, second electrode layer; 109, passivation layer; 201, N-type electrode; 202, P-type electrode; 203, readout circuit. DETAILED DESCRIPTION

[0051] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0052] Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of this application.

[0053] See also Figure 1 , the embodiment of the present application provides a three-band image sensor, including:

[0054] N-type electrode 201, P-type electrode 202 and readout circuit 203, and sequentially stacked substrate layer 101, silicon oxide layer 102, aluminum oxide layer 103, first electrode layer 104, ultraviolet light sensing layer 105, visible light sensing layer 106, infrared light sensing layer 107, second electrode layer 108 and passivation layer 109.

[0055] A plurality of rectangular grooves of the same shape and distributed at preset intervals sequentially penetrate the second electrode layer 108, the infrared light sensing layer 107, the visible light sensing layer 106 and the ultraviolet light sensing layer 105; the ultraviolet light sensing layer 105 adopts an intrinsic aluminum arsenide material; the visible light sensing layer 106 adopts an intrinsic gallium arsenide material; and the infrared light sensing layer 107 adopts an intrinsic germanium-based material with a 6-degree bevel.

[0056] The passivation layer 109 uniformly covers the second electrode layer and the inner walls of each rectangular groove.

[0057] The N-type electrode 201 is disposed in the rectangular groove and passes through the passivation layer 109 to connect to the first electrode layer 104 ; the P-type electrode 202 passes through the passivation layer 109 to connect to the second electrode layer 108 ; and the readout circuit 203 is respectively connected to the N-type electrode 201 and the P-type electrode 202 .

[0058] Among them, the three-band sensing layers of the present application respectively collect light waves of 100-400nm (ultraviolet band), 380-750nm (visible light band) and 1000-2500nm (short-wave infrared band), realizing a wide spectrum response from ultraviolet to visible light to short-wave infrared. This wide spectrum coverage capability enables the image sensor to work under a variety of lighting conditions.

[0059] Specifically, the present application uses AlAs, GaAs and Ge which are stable in epitaxial process as the ultraviolet light sensing layer 105, the visible light sensing layer 106 and the infrared light sensing layer 107 respectively. The three vertically stacked sensing layer materials have good crystal quality and excellent interface quality, and low defect density, which is beneficial to improving the resolution and yield of ultraviolet-visible light-short-wave infrared three-band image sensors, and is suitable for mass production and large-scale application of ultraviolet-visible light-short-wave infrared image sensors.

[0060] The AlAs ultraviolet light sensing layer 105, GaAs visible light sensing layer 106 and Ge infrared light sensing layer 107 of the present application, in addition to having very good lattice polarity matching, also have a certain resonant cavity effect, which can significantly improve the performance indicators of the three-band image sensor, such as dark current, peak responsivity, peak quantum efficiency and operating speed.

[0061] In a specific production process, the thickness of the silicon oxide layer 102 is between 10 nanometers and 100 nanometers; the thickness of the aluminum oxide layer 103 is 10 nanometers; and the thickness of the first electrode layer 104 and the second electrode layer 108 are both between 100 nanometers and 500 nanometers.

[0062] The thickness of the ultraviolet light sensing layer 105 is between 100 nanometers and 500 nanometers; the thickness of the visible light sensing layer 106 is between 100 nanometers and 1000 nanometers; the thickness of the infrared light sensing layer 107 is between 500 nanometers and 3000 nanometers. The first electrode layer 104 is a P-type aluminum arsenide electrode layer with a bevel of 6 degrees; the second electrode layer 108 is an N-type germanium electrode layer with a bevel of 6 degrees; or the first electrode layer 104 is an N-type aluminum arsenide electrode layer with a bevel of 6 degrees; the second electrode layer 108 is a P-type germanium electrode layer with a bevel of 6 degrees.

[0063] Furthermore, in addition to germanium, the germanium-based material used in the infrared light sensing layer 107 may also include Group IV semiconductor material structures such as germanium-tin alloy, germanium quantum well, germanium-silicon quantum well, germanium-tin quantum well or silicon-germanium-tin quantum well.

[0064] In the above embodiment, a three-band image sensor is provided, wherein the ultraviolet light sensing layer 105 is made of intrinsic aluminum arsenide material, the visible light sensing layer 106 is made of intrinsic gallium arsenide material, and the infrared light sensing layer 107 is made of intrinsic germanium material with a 6-degree bevel. The lattice constants of these three semiconductor materials are respectively and The lattice is extremely matched, which solves the lattice mismatch and polarity mismatch problems between the three sensing layers in the prior art; in addition, compared with InGaAs, PbS, and SnS short-wave infrared photoelectric materials, the epitaxial process of aluminum arsenide, gallium arsenide, and germanium materials of the present application is stable and simple, with high product yield and lower manufacturing cost, and is suitable for mass production of image sensors.

[0065] In some embodiments, the substrate layer 101 may be a glass substrate or a sapphire substrate.

[0066] Glass substrates or sapphire substrates are highly transparent in the ultraviolet-visible-shortwave infrared bands, and have the characteristics of low absorption and low scattering in the ultraviolet band, visible light band and shortwave infrared band, allowing optical signals in the ultraviolet-visible-shortwave infrared band to penetrate effectively, reducing light loss, achieving extremely high light collection efficiency, and improving the sensitivity and accuracy of the sensor.

[0067] Secondly, glass substrates and sapphire substrates have the advantage of large size and good uniformity, which can ensure the large-area uniformity of UV-visible-shortwave infrared imaging chips and easily realize large-area focal plane arrays. In addition, glass substrates and sapphire substrates have good environmental stability and can maintain stable performance under different environmental conditions, which makes the formed UV-visible-shortwave infrared image sensors applicable in harsh environments such as high temperature, high humidity, and strong radiation.

[0068] The present application embodiment provides a method for manufacturing a three-band image sensor, comprising:

[0069] Step S11, providing a silicon substrate 001 with a bevel of 6 degrees; stacking a germanium buffer layer 002 with a bevel of 6 degrees, a second electrode layer 108, an infrared light sensing layer 107, a visible light sensing layer 106, an ultraviolet light sensing layer 105, a first electrode layer 104 and an aluminum oxide layer 103 in sequence on the silicon substrate 001 to obtain a donor substrate.

[0070] Among them, the ultraviolet light sensing layer 105 is made of intrinsic aluminum arsenide material; the visible light sensing layer 106 is made of intrinsic gallium arsenide material; and the infrared light sensing layer 107 is made of intrinsic germanium-based material with an intrinsic bevel of 6 degrees. Only the silicon substrate 001, the germanium buffer layer 002, the second electrode layer 108, the infrared light sensing layer 107 and the first electrode layer 104 are beveled at 6 degrees. The use of the silicon substrate 001 with a bevel of 6 degrees in this application can solve the polarity mismatch problem between the fourth-group Ge material and the third- and fifth-group GaAs and AlAs materials.

[0071] Step S12, providing a substrate layer 101; stacking a silicon oxide layer 102 on the substrate layer 101 to obtain a receptor substrate.

[0072] The substrate layer 101 is a glass substrate or a sapphire substrate; the thickness of the germanium buffer layer 002 is between 100 nanometers and 500 nanometers. The thickness ranges of the second electrode layer 108, the infrared light sensing layer 107, the visible light sensing layer 106, the ultraviolet light sensing layer 105, the first electrode layer 104 and the aluminum oxide layer 103 have been given in the above embodiments and will not be repeated here.

[0073] Step S13, wafer bonding the donor substrate and the acceptor substrate.

[0074] Specifically, Figure 2 As shown, wafer bonding is to flip the donor substrate 180 degrees and then superimpose it on the acceptor substrate.

[0075] The stacking of semiconductor layers by wafer bonding can ensure that the vertically stacked sensing layer materials have good crystal quality and excellent interface quality, low defect density, and improved product yield and resolution.

[0076] Step S14, removing the silicon substrate 001 and the germanium buffer layer 002 to obtain a sensor wafer; specifically, the silicon substrate 001 and the germanium buffer layer 002 may be removed by back thinning, wet etching, dry etching or chemical mechanical polishing.

[0077] Step S15, a plurality of rectangular grooves of the same shape and distributed at preset intervals are provided on the sensor wafer; the rectangular grooves sequentially penetrate the second electrode layer 108, the infrared light sensing layer 107, the visible light sensing layer 106 and the ultraviolet light sensing layer 105.

[0078] Specifically, see Figure 3 After the rectangular groove penetrates the ultraviolet light sensing layer 105 , it is necessary to further remove part of the first electrode layer 104 to ensure that the first electrode layer 104 can be exposed and connected to the N-type electrode 201 passing through the passivation layer 109 .

[0079] It is worth noting that the manufacturing method of this embodiment is a manufacturing method of a table-type ultraviolet-visible light-short-wave infrared image sensor. It can be considered that after the rectangular grooves are punched, the second electrode layer 108, the infrared light sensing layer 107, the visible light sensing layer 106 and the ultraviolet light sensing layer 105 between the two grooves form a "table" to obtain an ultraviolet-visible light-short-wave infrared pixel.

[0080] Step S16 , providing a passivation layer 109 , an N-type electrode 201 and a P-type electrode 202 , and connecting the N-type electrode 201 and the P-type electrode 202 to a readout circuit 203 .

[0081] See also Figure 4In the present application, the flip-chip technology can be used to perform In bump bonding or Cu bump bonding on the readout circuit 203 and the UV-visible-shortwave infrared focal plane array chip.

[0082] See also Figure 5 Another embodiment of the present application further provides a three-band image sensor, including:

[0083] N-type electrode 201, P-type electrode 202 and readout circuit 203, and sequentially stacked substrate layer 101, silicon oxide layer 102, aluminum oxide layer 103, first electrode layer 104, ultraviolet light sensing layer 105, visible light sensing layer 106, infrared light sensing layer 107, second electrode layer 108 and passivation layer 109; multiple rectangular grooves of the same shape and distributed at preset intervals sequentially penetrate infrared light sensing layer 107, visible light sensing layer 106 and ultraviolet light sensing layer 105; second electrode layer 108 is located between two adjacent rectangular grooves, embedded in infrared light sensing layer 107 and the length is less than the preset interval. Ultraviolet light sensing layer 105 is made of intrinsic aluminum arsenide material; visible light sensing layer 106 is made of intrinsic gallium arsenide material; infrared light sensing layer 107 is made of intrinsic germanium material with a 6-degree bevel; passivation layer 109 is evenly covered on the second electrode layer 108 and the inner wall of each rectangular groove.

[0084] The N-type electrode 201 is disposed in the rectangular groove and passes through the passivation layer 109 to connect to the first electrode layer 104 ; the P-type electrode 202 passes through the passivation layer 109 to connect to the second electrode layer 108 ; and the readout circuit 203 is respectively connected to the N-type electrode 201 and the P-type electrode 202 .

[0085] The thickness of the silicon oxide layer 102 is between 10 nanometers and 100 nanometers; the thickness of the aluminum oxide layer 103 is 10 nanometers; and the thickness of the first electrode layer 104 and the second electrode layer 108 are both between 100 nanometers and 500 nanometers.

[0086] The thickness of the ultraviolet light sensing layer 105 is between 100 nanometers and 500 nanometers; the thickness of the visible light sensing layer 106 is between 100 nanometers and 1000 nanometers; the thickness of the infrared light sensing layer 107 is between 500 nanometers and 3000 nanometers. The first electrode layer 104 is a P-type aluminum arsenide electrode layer with a bevel of 6 degrees; the second electrode layer 108 is an N-type germanium electrode layer with a bevel of 6 degrees; or the first electrode layer 104 is an N-type aluminum arsenide electrode layer with a bevel of 6 degrees; the second electrode layer 108 is a P-type germanium electrode layer with a bevel of 6 degrees.

[0087] In addition to germanium, the germanium-based material used in the infrared light sensing layer 107 may also include a group IV semiconductor material structure such as germanium-tin alloy, germanium quantum well, germanium-silicon quantum well, germanium-tin quantum well or silicon-germanium-tin quantum well.

[0088] It can be considered that, in the image sensor of this embodiment, except for the arrangement of the second electrode layer 108, the thickness limitation and material type limitation of other semiconductor layers are consistent with those of the mesa-type image sensor of the aforementioned embodiment. Since the second electrode layer 108 is injected into the infrared light sensing layer 107, the thickness of the infrared light sensing layer 107 must be greater than that of the second electrode layer 108.

[0089] Specifically, almost all ultraviolet-visible-short-wave infrared image sensors in the current field use the table structure defined in the aforementioned embodiment. This structure is suitable for focal plane arrays with larger pixel sizes and can meet the actual needs of some application scenarios. However, for pixels with small pixel pitches, since only the passivation layer 109 covers both sides of the second electrode layer 108, there is a prominent leakage current problem on the sidewalls of the table structure, and the electrical crosstalk between adjacent small pixels increases, resulting in an increase in dark current, which is not conducive to the improvement of the performance of the focal plane array. Although surface treatment and passivation processes can minimize sidewall leakage current, it is still very challenging to suppress the sidewall leakage current of pixels with small pixel pitches in the table structure.

[0090] Therefore, the present application further proposes a three-band image sensor with a planar structure, in which the sensing layers of ultraviolet light, visible light and infrared light still use AlAs, GaAs and Ge structures to solve the lattice adaptation problem. In addition, compared with the sensor with a table structure, the second electrode layer 108 of the planar structure sensor will not be exposed. Figure 5 As shown, the length of the second electrode layer 108 is smaller than the length of the table formed by the adjacent rectangular grooves, and the second electrode layer 108 is entirely embedded in the infrared light sensing layer 107 thereunder, so that the junction interface is buried, thereby eliminating the electrical crosstalk between adjacent small pixels as much as possible, and completely avoiding the problems of sensor surface leakage current and sidewall leakage current, making it more suitable for manufacturing germanium sensors with small pixel pitch and low dark current.

[0091] Preferably, the length of the second electrode layer 108 occupies half of the entire mesa length, that is, the length of the second electrode layer 108 is 1 / 2 of the length of the sensing layer, so that the working performance and leakage level of the second electrode layer 108 can be balanced.

[0092] The embodiment of the present application also provides a method for manufacturing a three-band image sensor, comprising:

[0093] Step S21, providing a silicon substrate 001 with a bevel of 6 degrees; stacking a germanium buffer layer 002 with a bevel of 6 degrees, an infrared light sensing layer 107, a visible light sensing layer 106, an ultraviolet light sensing layer 105, a first electrode layer 104 and an aluminum oxide layer 103 in sequence on the silicon substrate 001 to obtain a donor substrate; wherein the ultraviolet light sensing layer 105 is made of an intrinsic aluminum arsenide material; the visible light sensing layer 106 is made of an intrinsic gallium arsenide material; and the infrared light sensing layer 107 is made of an intrinsic germanium-based material with a bevel of 6 degrees.

[0094] The substrate layer 101 is a glass substrate or a sapphire substrate; the thickness of the germanium buffer layer 002 is between 100 nanometers and 500 nanometers.

[0095] As for the thickness ranges and material limitations of the second electrode layer 108 , the infrared light sensing layer 107 , the visible light sensing layer 106 , the ultraviolet light sensing layer 105 , the first electrode layer 104 and the aluminum oxide layer 103 , they have been given in the above embodiments and will not be repeated here.

[0096] Step S22, providing a substrate layer 101; stacking a silicon oxide layer 102 on the substrate layer 101 to obtain a receptor substrate.

[0097] Step S23, wafer bonding the donor substrate and the acceptor substrate.

[0098] Step S24, removing the silicon substrate 001 and the germanium buffer layer 002 to obtain a sensor wafer; specifically, the silicon substrate 001 and the germanium buffer layer 002 may be removed by back thinning, wet etching, dry etching or chemical mechanical polishing.

[0099] The steps for manufacturing the planar sensor wafer here are basically the same as the method for manufacturing the table-type image sensor, the only difference being that the donor substrate of the planar sensor does not have the second electrode layer 108, which needs to be generated by ion implantation in the next step.

[0100] Step S25 , forming a plurality of second electrode layers 108 on the infrared light sensing layer 107 by ion implantation.

[0101] like Figure 6 As shown, in fact, in addition to the ion implantation method, the second electrode layer 108 can also be formed by ion diffusion.

[0102] When generating the second electrode layer 108 , it should be noted that the distance between two adjacent second electrode layers 108 should be greater than the preset interval, so as to facilitate the subsequent arrangement of the rectangular grooves.

[0103] Step S26, setting a plurality of rectangular grooves of the same shape and distributed at preset intervals on the sensor wafer; the rectangular grooves sequentially penetrate the infrared light sensing layer 107, the visible light sensing layer 106 and the ultraviolet light sensing layer 105; the second electrode layer 108 is located between two adjacent rectangular grooves, embedded in the infrared light sensing layer 107 and with a length less than the preset interval.

[0104] Specifically, when setting the rectangular grooves, the second electrode layer 108 is positioned between the two rectangular grooves as much as possible to avoid the side of the second electrode layer 108 being exposed to cause current leakage, thereby obtaining a planar ultraviolet-visible light-shortwave infrared pixel.

[0105] Step S27 , providing a passivation layer 109 , an N-type electrode 201 and a P-type electrode 202 , and connecting the N-type electrode 201 and the P-type electrode 202 to a readout circuit 203 .

[0106] See also Figure 7 In the present application, the flip-chip technology can be used to perform In bump bonding or Cu bump bonding on the readout circuit 203 and the UV-visible-shortwave infrared focal plane array chip.

[0107] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0108] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A three-band image sensor, characterized in that: include: N-type electrode, P-type electrode and readout circuit, and sequentially stacked substrate layer, silicon oxide layer, aluminum oxide layer, first electrode layer, ultraviolet light sensing layer, visible light sensing layer, infrared light sensing layer, second electrode layer and passivation layer; A plurality of rectangular grooves of the same shape and distributed at preset intervals sequentially penetrate the second electrode layer, the infrared light sensing layer, the visible light sensing layer and the ultraviolet light sensing layer; the ultraviolet light sensing layer adopts an intrinsic aluminum arsenide material; the visible light sensing layer adopts an intrinsic gallium arsenide material; the infrared light sensing layer adopts an intrinsic germanium material with a 6-degree bevel; The passivation layer uniformly covers the second electrode layer and the inner walls of each rectangular groove; The N-type electrode is arranged in the rectangular groove, passes through the passivation layer to connect to the first electrode layer; the P-type electrode passes through the passivation layer to connect to the second electrode layer; the readout circuit is respectively connected to the N-type electrode and the P-type electrode.

2. The three-band image sensor according to claim 1, characterized in that: The substrate layer is a glass substrate or a sapphire substrate; the thickness of the silicon oxide layer is between 10 nanometers and 100 nanometers.

3. The three-band image sensor according to claim 1, characterized in that: The first electrode layer is a P-type aluminum arsenide electrode layer with a 6-degree bevel; the second electrode layer is an N-type germanium electrode layer with a 6-degree bevel; or the first electrode layer is an N-type aluminum arsenide electrode layer with a 6-degree bevel; the second electrode layer is a P-type germanium electrode layer with a 6-degree bevel.

4. The three-band image sensor according to claim 1, characterized in that: The thickness of the aluminum oxide layer is 10 nanometers; the thickness of the first electrode layer and the second electrode layer are both between 100 nanometers and 500 nanometers.

5. The three-band image sensor according to claim 1, characterized in that: The thickness of the ultraviolet light sensing layer is between 100 nanometers and 500 nanometers; the thickness of the visible light sensing layer is between 100 nanometers and 1000 nanometers; and the thickness of the infrared light sensing layer is between 500 nanometers and 3000 nanometers.

6. The three-band image sensor according to claim 1, characterized in that: The germanium series materials used in the infrared light sensing layer include germanium-tin alloy, germanium quantum well, germanium-silicon quantum well, germanium-tin quantum well or silicon-germanium-tin quantum well.

7. A method for manufacturing a three-band image sensor, characterized in that: include: Providing a silicon substrate with a bevel of 6 degrees; sequentially stacking a germanium buffer layer with a bevel of 6 degrees, a second electrode layer, an infrared light sensing layer, a visible light sensing layer, an ultraviolet light sensing layer, a first electrode layer and an aluminum oxide layer on the silicon substrate to obtain a donor substrate; The ultraviolet light sensing layer is made of intrinsic aluminum arsenide material; the visible light sensing layer is made of intrinsic gallium arsenide material; the infrared light sensing layer is made of intrinsic germanium material with a bevel of 6 degrees; Providing a substrate layer; stacking a silicon oxide layer on the substrate layer to obtain an acceptor substrate; Wafer bonding the donor substrate and the acceptor substrate; removing the silicon substrate and the germanium buffer layer to obtain a sensor wafer; A plurality of rectangular grooves of the same shape and distributed at preset intervals are arranged on the sensor wafer; the rectangular grooves sequentially penetrate the second electrode layer, the infrared light sensing layer, the visible light sensing layer and the ultraviolet light sensing layer; A passivation layer, an N-type electrode and a P-type electrode are provided, and the N-type electrode and the P-type electrode are connected to a readout circuit.

8. The method for manufacturing a three-band image sensor according to claim 7, characterized in that: The step of removing the silicon substrate and the germanium buffer layer to obtain a sensor wafer comprises: The silicon substrate and the germanium buffer layer are removed by back thinning, wet etching, dry etching or chemical mechanical polishing.

9. A three-band image sensor, characterized in that: include: N-type electrode, P-type electrode and readout circuit, and sequentially stacked substrate layer, silicon oxide layer, aluminum oxide layer, first electrode layer, ultraviolet light sensing layer, visible light sensing layer, infrared light sensing layer, second electrode layer and passivation layer; A plurality of rectangular grooves of the same shape and distributed at preset intervals sequentially penetrate the infrared light sensing layer, the visible light sensing layer and the ultraviolet light sensing layer; the second electrode layer is located between two adjacent rectangular grooves, embedded in the infrared light sensing layer and has a length less than the preset interval; the ultraviolet light sensing layer is made of intrinsic aluminum arsenide material; the visible light sensing layer is made of intrinsic gallium arsenide material; the infrared light sensing layer is made of germanium-based material with an intrinsic bevel of 6 degrees; The passivation layer uniformly covers the second electrode layer and the inner walls of each rectangular groove; The N-type electrode is arranged in the rectangular groove, passes through the passivation layer to connect to the first electrode layer; the P-type electrode passes through the passivation layer to connect to the second electrode layer; the readout circuit is respectively connected to the N-type electrode and the P-type electrode.

10. A method for manufacturing a three-band image sensor, characterized in that: include: Providing a silicon substrate with a bevel cut of 6 degrees; sequentially stacking a germanium buffer layer with a bevel cut of 6 degrees, an infrared light sensing layer, a visible light sensing layer, an ultraviolet light sensing layer, a first electrode layer and an aluminum oxide layer on the silicon substrate to obtain a donor substrate; The ultraviolet light sensing layer is made of intrinsic aluminum arsenide material; the visible light sensing layer is made of intrinsic gallium arsenide material; the infrared light sensing layer is made of intrinsic germanium material with a bevel of 6 degrees; Providing a substrate layer; stacking a silicon oxide layer on the substrate layer to obtain an acceptor substrate; Wafer bonding the donor substrate and the acceptor substrate; removing the silicon substrate and the germanium buffer layer to obtain a sensor wafer; forming a plurality of second electrode layers on the infrared light sensing layer by ion implantation; A plurality of rectangular grooves of the same shape and distributed at preset intervals are arranged on the sensor wafer; the rectangular grooves sequentially penetrate the infrared light sensing layer, the visible light sensing layer and the ultraviolet light sensing layer; the second electrode layer is located between two adjacent rectangular grooves, embedded in the infrared light sensing layer and has a length less than the preset interval; A passivation layer, an N-type electrode and a P-type electrode are provided, and the N-type electrode and the P-type electrode are connected to a readout circuit.

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