Light detection element

Abstract

The present invention discloses a light detection element comprising a first semiconductor layer, an absorption structure, a second semiconductor layer, and a blocking layer. The absorption structure is located on the first semiconductor layer and has a first conduction band, a first valence band, and a first band gap. The second semiconductor layer is located on the absorption structure and has a second conduction band, a second valence band, and a second band gap. The blocking layer is located between the absorption structure and the second semiconductor layer and has a third conduction band, a third valence band, and a third band gap. The third conduction band is larger than the second conduction band, or the third valence band is smaller than the second valence band.

Description

Technical Field

[0001] The present invention relates to a light detection (detection) element, and in particular to a light detection element comprising a carrier blocking layer. Background Art

[0002] With technological advancements, sensing components are finding increasingly widespread applications, such as in homes, automobiles, medical devices, and consumer electronics. Currently, sensing components utilize optical multilayers to filter out noise light, enabling them to accurately respond only to specific light sources. However, optical multilayers require additional production costs and are less effective at blocking obliquely incident noise light. Therefore, effectively removing noise light and improving the accuracy of light detection components remain ongoing challenges. Summary of the Invention

[0003] A light detection element comprises a first semiconductor layer, an absorption structure, a second semiconductor layer, and a blocking layer. The absorption structure is located on the first semiconductor layer, the second semiconductor layer is located on the absorption structure, and the blocking layer is located between the absorption structure and the second semiconductor layer. The absorption structure has a first conduction band, a first valence band, and a first band gap; the second semiconductor layer has a second conduction band, a second valence band, and a second band gap; and the blocking layer has a third conduction band, a third valence band, and a third band gap. The third conduction band is larger than the second conduction band, or the third valence band is smaller than the second valence band.

[0004] A sensing module includes a carrier and a light detecting element as described above located on the carrier. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1A is a top view schematically illustrating a light detection element according to an embodiment of the present invention;

[0006] Figure 1B for Figure 1A Schematic diagram of the cross section along line AA';

[0007] Figure 2 is a cross-sectional schematic diagram of a light detection element according to an embodiment of the present invention;

[0008] Figure 3 is a schematic cross-sectional view of a light detection element according to an embodiment of the present invention;

[0009] Figure 4 is a schematic cross-sectional view of a light detection element according to an embodiment of the present invention;

[0010] Figure 5 is a cross-sectional schematic diagram of a light detection element according to an embodiment of the present invention;

[0011] Figure 6FIG. 1 is a cross-sectional schematic diagram of a sensing module according to an embodiment of the present invention.

[0012] Explanation of symbols

[0013] 100, 200, 300, 400, 500 light detection elements

[0014] 11 base plate

[0015] 121 first semiconductor layer

[0016] 122 Absorption structure

[0017] 123 Second semiconductor layer

[0018] 124 Blocking Structure

[0019] 125 contact structure

[0020] 126 third semiconductor layer

[0021] 127 Reflective Structure

[0022] 128 joint structure

[0023] 13. First electrode

[0024] 14. Second electrode

[0025] 16 Modification Area

[0026] 20 sensor modules

[0027] 210 carrier

[0028] 211 Light Emitting Element

[0029] 212 light detection element

[0030] 213 First Sealing Structure

[0031] 214 Second sealing structure DETAILED DESCRIPTION

[0032] The following embodiments are accompanied by accompanying drawings to illustrate the concepts of the present invention. Similar or identical parts are numbered the same in the drawings and descriptions. In the drawings, the shape, thickness, or height of the components may be enlarged or reduced within reasonable limits. The various embodiments listed in the present invention are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. Any obvious modifications or changes made to the present invention do not depart from the spirit and scope of the present invention.

[0033] In addition, other layers / structures or steps may be incorporated in the following embodiments. For example, the description of "forming a second layer / structure on a first layer / structure" may include an embodiment in which the first layer / structure directly contacts the second layer / structure, or may include an embodiment in which the first layer / structure indirectly contacts the second layer / structure, that is, there are other layers / structures between the first layer / structure and the second layer / structure. In addition, the spatial relative relationship between the first layer / structure and the second layer / structure may change depending on the operation or use of the device. On the other hand, different embodiments in the present disclosure may have repeated numbers and / or letters. Repetition is for simplicity and clarity, not for indicating the relationship between different embodiments.

[0034] Figure 1A FIG. 1 is a top view of a light detection element 100 according to an embodiment of the present invention. Figure 1B for Figure 1A Schematic cross-sectional view along line AA'. The photodetection element 100 is used to absorb light and convert light energy into electrical energy or photocurrent. In one embodiment, the photodetection element may be a photodiode. The photodetection element 100 includes a substrate 11, a first semiconductor layer 121, an absorption structure 122, a second semiconductor layer 123, a first electrode 13, and a second electrode 14. The substrate 11 can support the structures located thereon. The absorption structure 122 is located between the first semiconductor layer 121 and the second semiconductor layer 123. The first electrode 13 and the second electrode 14 electrically connect the first semiconductor layer 121, the absorption structure 122, and the second semiconductor layer 123 to conduct the photocurrent generated by the light absorption by the photodetection element 100. The first electrode 13 and the second electrode 14 are located on opposite sides of the substrate 11, respectively, forming a vertical configuration for the photodetection element 100. In another embodiment, the first electrode 13 and the second electrode 14 may be located on the same side of the substrate 11 , so that the light detecting element 100 forms a horizontal or flip-chip structure.

[0035] The first semiconductor layer 121 and the second semiconductor layer 123 comprise doped semiconductor layers and have different or identical conductivity types (n-type or p-type) by adding dopants. If holes are the majority carriers, it is called p-type, and if electrons are the majority carriers, it is called n-type. The absorption structure 122 comprises a doped, undoped, or unintentionally doped semiconductor structure. The dopant may be magnesium (Mg), carbon (C), zinc (Zn), silicon (Si), selenium (Se), or tellurium (Te).

[0036] The absorption structure 122 is the area of the optical detection element 100 for absorbing light, and the wavelength range of the light to be absorbed is determined according to the material of the absorption structure 122 (or the band gap). In other words, the absorption structure 122 can absorb light with energy greater than its band gap. The band gap of the absorption structure 122 can be designed to be between 0.72 ev and 1.77 ev (the corresponding wavelength is infrared light between 700 nm and 1700 nm), between 1.77 ev and 2.03 ev (the corresponding wavelength is red light between 610 nm and 700 nm), between 2.1 ev and 2.175 ev (the corresponding wavelength is yellow light between 570 nm and 590 nm), between 2.137 ev and 2.48 ev (the corresponding wavelength is green light between 500 nm and 580 nm), between 2.53 ev and 3.1 ev (the corresponding wavelength is blue or deep blue light between 400 nm and 490 nm), or between 3.1 ev and 4.96 ev (the corresponding wavelength is ultraviolet light between 250 nm and 400 nm).

[0037] The optical detection element 100 may include a quantum well structure, a single heterostructure or a double heterostructure. The first semiconductor layer 121, the second semiconductor layer 123 and the absorption structure 122 may comprise group III-V compound semiconductors, such as GaAs, InP, InGaAs, AlGaAs, AlGaInAs, GaP, InGaP, AlInP, AlGaInP, GaN, InGaN, AlGaN, AlGaInN, AlAsSb, InGaAsP, InGaAsN or AlGaAsP.

[0038] In this embodiment, unless otherwise specified, chemical formulas include "stoichiometric compounds" and "non-stoichiometric compounds". Among them, "stoichiometric compounds" are, for example, the total element dose of group III elements is the same as the total element dose of group V elements. Conversely, "non-stoichiometric compounds" are, for example, the total element dose of group III elements is different from the total element dose of group V elements. For example, the chemical formula AlGaAs series represents containing group III elements aluminum (Al) and / or gallium (Ga), and containing group V element arsenic (As), where the total element dose of group III elements (aluminum and / or gallium) can be the same or different from the total element dose of group V element (arsenic).

[0039] In addition, when each compound represented by the chemical formula is a stoichiometric compound, AlGaAs represents Al x1 Ga (1-x1) As, where 0 < x1 < 1; AlInP represents Al x2 In (1-x2) P, where 0 < x2 < 1; AlGaInP represents (Aly1 Ga (1-y1) ) (1-x3) In x3 P, where 0 < x3 < 1, 0 < y1 < 1; AlGaInAs represents (Al y2 Ga (1-y2) ) (1-x4) In x4 As, where 0 ≤ x4 ≤ 1, 0 ≤ y2 ≤ 1; AlGaN represents Al x5 Ga (1-x5) N, where 0 < x5 < 1; AlAsSb represents AlAs x6 Sb (1-x6) , where 0 ≤ x6 ≤ 1; InGaP represents In x7 Ga (1-x7) P, where 0 < x7 < 1; InGaAsP represents In x8 Ga (1-x8) As (1-y3) P y3 , where 0 ≤ x8 ≤ 1, 0 ≤ y3 ≤ 1; InGaAsN represents In x9 Ga (1-x9) As (1-y4) N y4 , where 0 < x9 < 1, 0 < y4 < 1; AlGaAsP represents Al x10 Ga (1-x10) As (1-y5) P y5 , where 0 < x10 < 1, 0 < y5 < 1; InGaAs represents In x11 Ga (1-x11) As, where 0 < x11 < 1; InGaN represents In x12 Ga (1-x12) N, where 0 < x12 < 1; AlGaInN represents (Al y6 Ga (1-y6) ) (1-x13) In x13 P, where 0 < x13 < 1, 0 < y6 < 1; AlInAs represents Al x14 In (1-x14) As, where 0 < x14 < 1.

[0040] The substrate 11 is a conductive material and includes a metal material, a semiconductor material, or a transparent conductive material. The metal material may be copper (Cu), aluminum (Al), chromium (Cr), tin (Sn), gold (Au), nickel (Ni), titanium (Ti), platinum (Pt), lead (Pb), zinc (Zn), cadmium (Cd), antimony (Sb), cobalt (Co), or alloys thereof. The semiconductor material may be a Group IV semiconductor or a Group III-V semiconductor, such as silicon (Si), germanium (Ge), silicon carbide (SiC), gallium nitride (GaN), gallium phosphide (GaP), gallium arsenide (GaAs), gallium arsenide phosphide (AsGaP), or indium phosphide (InP). The transparent conductive material may be an oxide or graphene. Examples of oxides include indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), cadmium tin oxide (CTO), antimony tin oxide (ATO), aluminum zinc oxide (AZO), zinc tin oxide (ZTO), gallium zinc oxide (GZO), indium tungsten oxide (IWO), or indium zinc oxide (IZO). The first semiconductor layer 121, the absorption structure 122, and the second semiconductor layer 123 may be grown on the substrate 11 or another growth substrate via epitaxial growth methods such as metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), or hydride vapor phase epitaxy (HVPE). If the first semiconductor layer 121, the absorption structure 122, and the second semiconductor layer 123 are grown on the growth substrate, they can be bonded to the substrate 11 via an adhesive layer (not shown) using a substrate transfer technique. The growth substrate can then be selectively removed. The conductivity type (eg, n-type or p-type) of the substrate 11 may be the same as or different from that of the first semiconductor layer 121 .

[0041] The first semiconductor layer 121 has a first conduction band E c1 , a first valence band (valence band) E v1 and the first band gap E1 (=E c1 -E v1 The absorption structure 122 has a second conductive band E c2 , a second valence band E v2 and a second band gap E2 (=E c2 -E v2 The second semiconductor layer 123 has a third conduction band E c3 , a second valence band E v3 and a third band gap E3 (=E c3 -E v3 ). When a semiconductor layer has a fixed chemical composition (e.g. In 0.5 Ga 0.5 P), its band gap energy is a fixed value and can be defined as a band gap Ex ; In some embodiments, when a semiconductor layer has a gradually varying chemical composition and the interface therein cannot be observed by a scanning electron microscope (SEM), this semiconductor layer with a gradually varying chemical composition can be regarded as a single layer, and its bandgap is a range; and the gradually varying chemical composition means that in the elemental composition of this semiconductor layer, at least the composition ratio of one element gradually increases or decreases along the epitaxial growth direction of this semiconductor layer. For example, In a Ga (1-a) P, 0.1 < a < 0.3, and the composition ratio of the In element in this semiconductor layer gradually increases from 0.1 to 0.3 along the epitaxial growth direction. In one embodiment, when this semiconductor layer with a gradually varying chemical composition is used to block electrons or holes, the maximum value in its bandgap range can be defined as the bandgap E of this semiconductor layer with a gradually varying chemical composition x . For a semiconductor structure used to block electrons or holes and having multiple semiconductor layers, such as the blocking structure 124, the maximum value of the bandgaps in the multiple semiconductor layers in this semiconductor structure can be defined as the bandgap E of this semiconductor structure X` . In one embodiment, the absorption structure 122 can include a single layer or multiple layers. When the absorption structure 122 is a single layer with a gradually varying chemical composition, the bandgap E of the absorption structure 122 x is defined as the minimum value in a bandgap range possessed by this single layer with a gradually varying chemical composition. If the absorption structure 122 includes multiple layers, then the minimum value in the bandgap range in these multiple layers is defined as the bandgap E of this absorption structure 122 x . The above method for defining the bandgap of the absorption structure 122 can also be used to define the bandgaps of the first semiconductor layer 121 and the second semiconductor layer 123. The second semiconductor layer 123 and the absorption structure 122 also define the second bandgap E2 and the third bandgap E3 in the same way. In addition, the absorption structure 122 can include a single layer or multiple layers. When the absorption structure 122 is composed of a single layer, the bandgap of this single layer is defined as the second bandgap E2; when the absorption structure 122 is composed of multiple layers, the minimum value of the bandgaps in these multiple layers is defined as the second bandgap E2

[0042] The incident light is incident on the photodetector 100 from the second semiconductor layer 123. In this embodiment, the third bandgap E3 is greater than the second bandgap E2. Therefore, when the energy of the incident light is less than the third bandgap E3 and greater than the second bandgap E2, the incident light will penetrate the second semiconductor layer 123 and be absorbed by the absorption structure 122 to generate electron-hole pairs, and then generate a photocurrent under the action of an electric field. When the energy of the incident light is greater than the third bandgap E3, it will be absorbed by the second semiconductor layer 123 to generate electron-hole pairs. In other words, assuming that the incident light has the first light in the first wavelength range and the second light in the second wavelength range, and the second wavelength range is less than the first wavelength range (i.e., the photon energy (E of the second lightn2 ) is greater than the photon energy of the first light (E n1 ), and the photon energy of the first light is less than the third band gap E3 and greater than the second band gap E2, and the photon energy of the second light is greater than the third band gap E3. When the incident light irradiates the light detection element 100, the second light having the second wavelength range is absorbed by the second semiconductor layer 123, and the first light having the first wavelength range penetrates the second semiconductor layer 123 and is absorbed by the absorption structure 122.

[0043] The light detection device 100 further includes a blocking layer 124 located between the absorption structure 122 and the second semiconductor layer 123 and can be grown using the aforementioned epitaxial method. The blocking layer 124 has a fourth conduction band E c4 , a fourth valence band E v4 and a fourth band gap E4 (=E c4 -E v4 The fourth band gap E4 is larger than the third band gap E3 and larger than the second band gap E2, and is used to block carrier flow, reducing the photocurrent generated by the electric field due to electron-hole pairs not generated in the absorption structure 122, thereby increasing the accuracy of the light detection device 100. Specifically, as described above, since the second semiconductor layer 123 absorbs the second light having a second wavelength range and generates electron-hole pairs, and under the action of the electric field, the electron holes (carriers) flow and generate photocurrent, the blocking layer 124 blocks the flow of carriers toward the first electrode 13 and / or the second electrode 14. This prevents the electron-hole pairs generated in the second semiconductor layer 123 from contributing to the photocurrent measured by the light detection device 100, thereby improving the accuracy and sensitivity of the light detection device 100. In one embodiment, the energy difference between the fourth band gap E4 and the third band gap E3 is between 0.05 eV and 1 eV (e.g., 0.1 eV or 0.5 eV).

[0044] In one embodiment, when the blocking layer 124 blocks electrons, the fourth conduction band E of the blocking layer 124 c4 is greater than the third conduction band E of the second semiconductor layer 123 c3 , that is, E c4 -E c3 >0, it can more effectively block the flow of electrons. In one embodiment, when the fourth conduction band E c4 is greater than the third conduction band E of the second semiconductor layer 123 c3 When the fourth band gap E4 can be greater than, less than or equal to the third band gap E3. In one embodiment, when the blocking layer 124 blocks holes, the fourth valence band E V4 is smaller than the third valence band E of the second semiconductor layer 123 v3 , that is, E V4 -E v3<0, it can more effectively block the flow of holes. Similarly, when the fourth valence band E V4 is smaller than the third valence band E of the second semiconductor layer 123 v3 When , the fourth band gap E4 may be greater than, less than or equal to the third band gap E3.

[0045] In one embodiment, the first semiconductor layer 121 is an n-type semiconductor layer and the second semiconductor layer 123 is a p-type semiconductor layer. When incident light enters the light detection device 100 from the second semiconductor layer 123, the blocking layer 124 blocks electrons from flowing toward the absorption structure 122. Therefore, the fourth conduction band E of the blocking layer 124 is c4 is greater than the third conduction band E of the second semiconductor layer 123 c3 In another embodiment, the first semiconductor layer 121 is a p-type semiconductor layer and the second semiconductor layer 123 is an n-type semiconductor layer. When the incident light enters the light detection element 100 from the second semiconductor layer 123, the blocking layer 124 blocks the holes from flowing toward the absorption structure 122. Therefore, the fourth valence band E of the blocking layer 124 is V4 is smaller than the third valence band E of the second semiconductor layer 123 v3 .

[0046] The barrier layer 124 has a thickness between 10 nm and 1 μm, and may be 50 nm, 100 nm, or 500 nm. The barrier layer 124 may be a doped, undoped, or unintentionally doped semiconductor layer and may comprise a Group III-V compound semiconductor, such as AlGaInAs, AlInAs, InGaP, AlInP, or InP. The barrier layer 124 may have the same conductivity type (n-type or p-type) as the second semiconductor layer 123.

[0047] In one embodiment, the blocking layer 124 includes aluminum, such as AlGaInAs, AlInAs, or AlInP, with the aluminum content (in atomic percentage) of all Group III elements ranging from 20% to 70% (e.g., 30%, 40%, or 50%). This facilitates electrons and holes generated by light absorption in the second semiconductor layer 123 to recombine or annihilate within the blocking layer 124, preventing the generation of photocurrent. In one embodiment, the third band gap E3 of the second semiconductor layer 123 is between 1.3 eV and 1.4 eV (e.g., InP), thereby improving the reliability of the light detection device 100.

[0048] In this embodiment, in the spectral response diagram of the light detection element 100, the light detection element 100 has a maximum EQE value (EQE maxBy setting the blocking layer 124, the EQE value of light with energy greater than the third band gap E3 is less than 15%×EQE max (e.g., 10%, 5%). For example, the absorption structure 122 of the light detection element 100 is made of InGaAs and can absorb light below 1700nm and has a maximum EQE value. The second semiconductor layer 123 is made of InP and can absorb light below 900nm. By setting the blocking layer 124, the EQE value of visible light (e.g., 700nm, 600nm, 500nm) is less than 15% × EQE. max .

[0049] In addition, in application, when designing the light detection element 100 to absorb or detect a target light, the material of the absorption structure 122 can be selected so that its second band gap E2 is equal to or slightly smaller than the energy E of the target light. o (E o ×0.9≤E2≤E o ), since both target light and non-target light with energy greater than or equal to the second band gap E2 are absorbed by the absorption structure 122, the light detection device 100 cannot absorb or detect only the target light. As previously described, since the second semiconductor layer 123 can absorb light with energy greater than the third band gap E3 and transmit light with energy less than the third band gap E3, the second semiconductor layer 123 can filter out some non-target light. The band gap difference between the second band gap E2 and the third band gap E3 (ΔE1 = E3 - E2) satisfies the requirement of 0.1 eV ≤ ΔE1 ≤ 0.5 eV, thereby increasing the practicality and accuracy of the light detection device 100. Furthermore, the provision of the blocking layer 124 ensures that the photocurrent generated by light absorption by the second semiconductor layer 123 does not affect the accuracy and sensitivity of the light detection device 100.

[0050] In one embodiment, the first semiconductor layer 121, the absorption structure 122, the second semiconductor layer 123, and the barrier layer 124 may be lattice-matched or lattice-mismatched. Specifically, the first semiconductor layer 121 has a first intrinsic lattice constant, the absorption structure 122 has a second intrinsic lattice constant, the second semiconductor layer 123 has a third intrinsic lattice constant, and the barrier layer 124 has a fourth intrinsic lattice constant. When the difference in the intrinsic lattice constants of the two layers is no greater than 0.1%, they are considered lattice-matched; when the difference in the intrinsic lattice constants of the two layers is greater than 0.1%, they are considered lattice-mismatched. Furthermore, when the absorption structure 122 is composed of a single layer, the lattice constant of the single layer is defined as the first intrinsic lattice constant. When the absorption structure 122 is composed of multiple layers, the average (arithmetic mean) of the intrinsic lattice constants of the multiple layers is defined as the first intrinsic lattice constant. The "intrinsic lattice constant" is defined as the lattice constant a0 of a layer that is substantially free of strain.

[0051] Furthermore, the lattice constant can be obtained by any suitable method. For example, it can be analyzed by diffraction pattern analysis using transmission electron microscopy (TEM), or the lattice constant information can be obtained by XRD (X-ray diffraction) at a temperature of 300 K, or can be obtained from books (e.g., "Properties of Semiconductor Alloys: Group IV, III–V, and II–VI Semiconductors," published by John Wiley & Sons Inc. in 2009).

[0052] The light detection device 100 may optionally include a contact structure 125 disposed between the second semiconductor layer 123 and the first electrode 13 to reduce the resistance between the second semiconductor layer 123 and the first electrode 13 and provide a low resistance path for current to flow.

[0053] Figure 2 FIG2 is a cross-sectional view of a light detection element 200 according to an embodiment of the present invention. The light detection element 200 has a similar structure to the light detection element 100 . Figure 2 and Figure 1A-1BThe same symbols are used to describe the same elements, and the materials and characteristics of these elements are as described above, so they will not be repeated here. The light detection element 200 further includes a third semiconductor layer 126 disposed between the blocking layer 124 and the second semiconductor layer 123, or disposed under the second semiconductor layer 123. The third semiconductor layer 126 has a fifth conduction band E c5 , the fifth valence band E v5 and a fifth band gap E5 (=E c5 -E v5 ). The fifth band gap E5 is smaller than the third band gap E3 and the fourth band gap E4 but larger than the second band gap E2. In one embodiment, when the blocking layer 124 blocks electrons, the fourth conduction band E c4 greater than the fifth conduction band E of the third semiconductor layer 126 c5 , that is, E c4 -E c5 In one embodiment, when the blocking layer 124 blocks holes, the fourth valence band E V4 is smaller than the fifth valence band E of the third semiconductor layer 126 V5 , that is, E V4 -E V5 <0. In one embodiment, the fifth band gap E5 is greater than, less than or equal to the fourth band gap E4.

[0054] As previously described, the second semiconductor layer 123 filters out some non-target light, while the third semiconductor layer 126 further absorbs non-target light with energy below the third band gap E3 and above the fifth band gap E5. This allows the absorption structure 122 to more accurately absorb target light, thereby increasing the practicality and accuracy of the light detection device 100. Furthermore, the provision of the blocking layer 124 prevents the flow of electron-hole pairs generated by light absorption by the third semiconductor layer 126, thereby preventing the generation of photocurrent. The band gap difference (ΔE2) between the second band gap E2 and the fifth band gap E5 satisfies the requirement of 0.05 eV ≤ ΔE2 ≤ 0.2 eV. The third semiconductor layer 126, the second semiconductor layer 123, and the blocking layer 124 have the same conductivity type (n-type or p-type).

[0055] In one embodiment, multiple semiconductor layers may be disposed between the second semiconductor layer 123 and the blocking layer 124 to absorb non-target light. In addition, when the blocking layer 124 blocks electrons, the fourth conduction band E of the blocking layer 124 c4 The fourth valence band E of the blocking layer 124 is greater than the conduction band of the semiconductor layer in direct contact with the blocking layer 124 to effectively block the flow of electrons. v4The valence band gap of the semiconductor layer in direct contact with the blocking layer 124 is smaller than that of the semiconductor layer, thereby effectively blocking the flow of holes. The plurality of semiconductor layers have the same conductivity type (n-type or p-type) as the second semiconductor layer 123 and the blocking layer 124. In one embodiment, the band gap of the semiconductor layers decreases from large to small along the direction from the second semiconductor layer 123 to the blocking layer 124.

[0056] Figure 3 FIG2 is a cross-sectional view of a light detection element 300 according to an embodiment of the present invention. The light detection element 300 has a similar structure to the light detection element 100 . Figure 3 Identical elements are depicted with the same reference numerals as in FIG. 1 , and the materials and properties of these elements are as previously described, so further description is omitted. The photodetection device 300 further includes a modified region 16 formed within the second semiconductor layer 123, the barrier layer 124, and a portion of the absorption structure 122. Specifically, ion diffusion or ion implantation techniques are employed to convert majority carriers in a region of the second semiconductor layer 123, the barrier layer 124, and the absorption structure 122 from electrons to holes or vice versa, thereby changing the conductivity type or level and forming the modified region 16. Regions of the second semiconductor layer 123, the barrier layer 124, and the absorption structure 122 that have not undergone ion diffusion or implantation retain their original conductivity type or level and are defined as unmodified regions. In this embodiment, the second semiconductor layer 123 and the barrier layer 124 have the same conductivity type (e.g., n-type), and the modified region 16 has a different conductivity type (e.g., p-type) than the second semiconductor layer 123 and the barrier layer 124. In addition, the first semiconductor layer 121 and the second semiconductor layer 123 also have the same conductivity type (eg, n-type).

[0057] Figure 4 FIG2 is a cross-sectional view of a light detection element 400 according to an embodiment of the present invention. The light detection element 400 has a similar structure to the light detection element 300 . Figure 4 and Figure 3 Identical elements are denoted by the same reference numerals, and their materials and properties are as previously described, so further description is omitted. The light detection device 400 further includes a third semiconductor layer 126 disposed between the barrier layer 124 and the second semiconductor layer 123, or disposed beneath the second semiconductor layer 123. Similarly, the conductivity type of the third semiconductor layer 126 is the same as that of the second semiconductor layer 123, the barrier layer 124, and the absorption structure 122, and the modified region 16 is also formed in the third semiconductor layer 126.

[0058] Figure 5 FIG2 is a cross-sectional view of a light detection element 500 according to an embodiment of the present invention. The light detection element 500 has a similar structure to the light detection element 300 . Figure 5 and Figure 3Identical components are represented by the same symbols, and the materials and properties of these components are as described above, so they will not be repeated here. The light detection element 500 also includes a reflective structure 127 located between the substrate 11 and the first semiconductor layer 121. This structure reflects light that has not been absorbed by the absorption structure 122 toward the absorption structure 122 for a second absorption, thereby increasing the photoelectric conversion efficiency. Furthermore, the provision of the reflective structure 127 can reduce the thickness of the absorption structure 122, thereby reducing the thickness of the light detection element 500, which is beneficial for small-scale applications. The reflective structure 127 comprises a metal or a metal alloy. Metals include gold, silver, aluminum, and copper. Metal alloys include alloys of the aforementioned metals. In one embodiment, the reflective structure 127 may include multiple layers of different refractive indices stacked alternately and periodically to form a distributed Bragg reflector (DBR). The material of the DBR may include semiconductors, oxides, or nitrides. Semiconductors include AlGaAs, GaAs, AlAs, AlGaInP, AlInP, InGaP, InP, and AlGaInAs. Oxides include aluminum oxide (Al2O3), silicon oxide (SiO2), titanium dioxide (TiO2), and niobium pentoxide (Nb2O5). Nitrides include silicon nitride (SiN x ).

[0059] Optionally, the light detection element 500 further includes a bonding structure 128 positioned between the reflective structure 127 and the substrate 11. The bonding structure 128 may be a single layer or multiple layers. The bonding structure 128 may be conductive or non-conductive. When conductive, the bonding structure 128 may comprise a transparent conductive material, metal, or alloy. Transparent conductive materials include, but are not limited to, indium tin oxide (ITO), indium oxide (InO), tin oxide (SnO), cadmium tin oxide (CTO), antimony tin oxide (ATO), aluminum zinc oxide (AZO), zinc tin oxide (ZTO), gallium zinc oxide (GZO), gallium phosphide (GaP), indium cerium oxide (ICO), indium tungsten oxide (IWO), indium titanium oxide (ITiO), indium zinc oxide (IZO), indium gallium oxide (IGO), gallium aluminum zinc oxide (GAZO), graphene, or combinations thereof. Metals include, but are not limited to, copper (Cu), aluminum (Al), tin (Sn), gold (Au), silver (Ag), lead (Pb), titanium (Ti), nickel (Ni), platinum (Pt), or tungsten (W). The alloy may include at least two selected from the group consisting of the aforementioned metals. When the bonding structure 128 is non-conductive, it may include an oxide or a nitride. The oxide or nitride can be described in the previous paragraph. Figure 6The figure is a cross-sectional schematic diagram of a sensing module 20 according to an embodiment of the present invention. The sensing module 20 includes a carrier 210, a light emitting element 211, a light detecting element 212, a first encapsulant 213, and a second encapsulant 214. The light detecting element 212 can be any of the aforementioned light detecting elements 100-500. The light emitting element 211 and the light detecting element 212 are located on the carrier 210 and connected to a circuit structure (not shown) on the carrier 210. The first encapsulant 213 covers the light emitting element 211, and the second encapsulant 214 covers the light detecting element 212. The carrier 210 can be a printed circuit board, an organic material, an inorganic material, or a flexible or bendable material. Organic materials can include phenolic resin, glass fiber, epoxy resin, polyimide, or bismaleimide-triazine resin (BT). Inorganic materials can include aluminum or ceramic materials. The flexible or bendable material may include PET, PI (polyimide), PVDF (polyvinylidene fluoride), or ETFE (ethylene tetrafluoroethylene). The first encapsulant 213 and the second encapsulant 214 may include epoxy, silicone, polyimide (PI), benzocyclobutene (BCB), perfluorocyclobutane (PFCB), Su8, acrylic resin, polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polycarbonate (PC), or polyetherimide.

[0060] The light detecting element 212 is designed to detect the light emitted by the light emitting element 211. Specifically, after the light emitting element 211 emits a light (the aforementioned target light), it is reflected by an object and directed toward the light detecting element 212. The light detecting element 212 detects the reflected light and generates a photocurrent. The wavelength range of the light emitted by the light emitting element 211 can be selected according to the application. For example, when used in medical sensing, the green light range, red light range, or infrared light range can be selected. The green light range (wavelength between 500nm and 580nm) can be used to detect heart rate and blood pressure, the red light range (wavelength between 610nm and 700nm) can be used to detect blood oxygen, and the infrared light range (wavelength between 700nm and 1700nm) can be used to detect blood oxygen, blood sugar, and blood lipids.

[0061] The sensing module 20 can be applied to products in the fields of lighting, medical treatment, display, communication, sensing, power supply system, etc., such as lamps, monitors, mobile phones, tablet computers, car dashboards, televisions, computers, wearable devices (such as watches, bracelets, necklaces, etc.), traffic signs, outdoor displays, medical equipment, etc.

[0062] The embodiments described above are merely for illustrating the technical concepts and features of the present invention. Their purpose is to enable persons skilled in the art to understand the contents of the present invention and implement them accordingly. They are not intended to limit the patent scope of the present invention. In other words, any equivalent changes or modifications made in accordance with the spirit disclosed in the present invention should still be covered by the patent scope of the present invention.

Claims

1. A light detection element, characterized in that: Include: a first semiconductor layer; an absorption structure, located on the first semiconductor layer, and having a first conduction band, a first valence band, and a first band gap; a second semiconductor layer located on the absorption structure and having a second conduction band, a second valence band, and a second band gap; a blocking layer located between the absorbing structure and the second semiconductor layer and having a third conduction band, a third valence band, and a third band gap; and a modified region formed in the barrier layer; The third conduction band is larger than the second conduction band, or the third valence band is smaller than the second valence band.

2. The light detection element according to claim 1, wherein The third band gap is larger than the second band gap.

3. The light detection element according to claim 1, wherein: The second semiconductor layer is InP.

4. The light detection element according to claim 1, wherein: The barrier layer has a thickness between 10 nm and 1 um. 5 . The light detection device as claimed in claim 1 , further comprising a substrate and a reflective structure located between the substrate and the first semiconductor layer.

6. The light detection element according to claim 1, wherein: The modified region is formed in the second semiconductor layer.

7. The light detection element according to claim 1, wherein: The barrier layer and the second semiconductor layer have the same conductivity type.

8. The light detection element according to claim 1, wherein: The first semiconductor layer and the second semiconductor layer have the same conductivity type.

9. The light detection element according to claim 1, wherein: The band gap difference between the third band gap and the second band gap is between 0.05 eV and 1 eV.

10. The light detection element according to claim 1, wherein: The third band gap is larger than the first band gap.

11. The light detection element according to claim 1, wherein: The band gap difference between the second band gap and the first band gap is between 0.1 eV and 0.5 eV.

12. The light detection element according to claim 1, wherein: The barrier layer comprises AlGaInAs, AlInAs, InGaP, AlInP or InP.

13. The light detection element according to claim 1, wherein: The barrier layer contains aluminum.

14. The light detection element according to claim 1, wherein: The barrier layer comprises AlGaInAs, AlInAs or AlInP, and the ratio of aluminum element in all group III elements is between 20% and 70%. 15 . The light detection device as claimed in claim 1 , further comprising a third semiconductor layer located between the second semiconductor layer and the blocking layer, the third semiconductor layer having a fourth conduction band, a fourth valence band, and a fourth band gap.

16. The light detection element according to claim 15, wherein: The third conduction band is larger than the fourth conduction band or the third valence band is smaller than the fourth valence band.

17. The light detection element according to claim 15, wherein: The fourth band gap is smaller than the third band gap and larger than the first band gap.

18. The light detection device according to claim 15, wherein: The band gap difference between the fourth band gap and the first band gap is between 0.05 eV and 0.2 eV.

19. The light detection device according to claim 7, wherein: The modified region has a different conductivity type from the blocking layer and the second semiconductor layer. 20 . The light detection device of claim 1 , further comprising a first electrode and a second electrode, wherein the first electrode is disposed on the second semiconductor layer and corresponds to the modified region, and the second electrode is disposed on a side of the first semiconductor layer away from the absorption structure.

21. A sensing module, characterized in that: Include: carrier; The light detection element as claimed in claim 1, located on the carrier. 22 . The sensing module as claimed in claim 21 , further comprising a sealing structure covering the light detecting element.

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