Infrared device

Abstract

The utility model provides a high-performance infrared device. An infrared device is provided with: a substrate (10); a semiconductor laminated part (20) provided on the substrate and having a first semiconductor layer (21), an active layer (23), and a second semiconductor layer (25); and a potential barrier layer (30) that is positioned between the substrate and the semiconductor laminated part (20) and that suppresses leakage current, the surface of the substrate on the side on which the semiconductor laminated part is provided is defined as a reference surface, and a first angle formed by the side surface of the first semiconductor layer and the surface parallel to the reference surface is different from a second angle formed by the side surface of the potential barrier layer and the surface parallel to the reference surface. A side surface of the first semiconductor layer is in contact with a side surface of the potential barrier layer.

Description

Technical Field

[0001] This disclosure relates to infrared devices and methods for manufacturing infrared devices. Background Technology

[0002] For example, infrared light with wavelengths around 2μm to 15μm is used in non-dispersive infrared absorption gas concentration measuring devices because gas molecules contain a large number of unique absorption bands. Infrared devices used in gas concentration measuring devices are crucial components that largely determine key performance aspects such as detection resolution, requiring high luminous intensity or photosensitive sensitivity at the desired wavelength. Here, infrared devices are collectively referred to as infrared emitting elements or infrared receiving elements. For example, light-emitting diodes (LEDs) are used as emitting elements. Alternatively, photodiodes (PDs) are used as receiving elements. Infrared devices using such semiconductors, through material design, can emit light and receive light in the desired wavelength band, enabling gas concentration measuring devices for detecting specific gases. Gas concentration measuring devices are, for example, NDIR (non-dispersive infrared) gas sensors (e.g., Patent Document 1). NDIR gas sensors can measure gas concentration using an infrared receiving element that receives infrared light in the absorption band corresponding to the target gas and an infrared emitting element that emits infrared light in that absorption band.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2004-271518 Utility Model Content

[0006] The problem to be solved by the utility model

[0007] Therefore, it is necessary to further improve the luminous intensity or detection sensitivity of infrared devices. When current leaks into the substrate, the luminous intensity or detection sensitivity of the infrared device decreases. Furthermore, when infrared devices and other components such as ICs are mounted on the same substrate, current may leak into those components, causing adverse effects.

[0008] This disclosure was made in view of the following circumstances, and its purpose is to provide a high-performance infrared device and a method for manufacturing an infrared device.

[0009] Methods for solving problems

[0010] (1) An infrared device according to an embodiment of the present disclosure includes: a substrate; a semiconductor stack disposed on the substrate, having a first semiconductor layer, an active layer and a second semiconductor layer; and a barrier layer located between the substrate and the semiconductor stack to suppress leakage current, wherein a side of the substrate on which the semiconductor stack is disposed is designated as a reference surface, and a first angle formed by the side of the first semiconductor layer and the surface parallel to the reference surface and a second angle formed by the side of the barrier layer and the surface parallel to the reference surface are different, and the side of the first semiconductor layer is in contact with the side of the barrier layer.

[0011] (2) As one embodiment of the present invention, in (1), there are multiple semiconductor stacks, and the multiple semiconductor stacks are connected in series.

[0012] (3) As one embodiment of the present invention, in (1) or (2), the potential barrier layer is an amorphous or polymeric layer.

[0013] (4) As one embodiment of the present invention, in (3), the potential barrier layer is a layer of silicon nitride, silicon dioxide, aluminum oxide, heated silicon nitride, silicone, silicon monoxide, epoxy resin or polyimide.

[0014] (5) As an embodiment of the present disclosure, in any one of (1) to (4), the potential barrier layer exists in a region, namely a first region, between the plurality of semiconductor stacks, and the thickness of the potential barrier layer in the stacking direction in the first region is thinner than the thickness of the potential barrier layer in the stacking direction in a second region that is not the first region.

[0015] (6) As an embodiment of the present disclosure, in any one of (1) to (5), the second angle is not perpendicular to the reference plane.

[0016] (7) As an embodiment of the present disclosure, in any one of (1) to (6), the thickness of the potential barrier layer in the stacking direction is 500 nm or more.

[0017] (8) As an embodiment of the present disclosure, in any one of (1) to (7), the refractive index of the potential barrier layer is lower than the average refractive index of the semiconductor stack.

[0018] (9) As an embodiment of this disclosure, in any one of (1) to (8), the infrared device has optical characteristics with a peak at wavelength λp [nm], and when the thickness of the semiconductor stack in the stacking direction is set to t [nm] and integers greater than or equal to 0 are set to m, the following equation (1) is satisfied:

[0019] [Formula 1]

[0020]

[0021] (10) As one embodiment of the present disclosure, in (1), the barrier layer is a semiconductor layer.

[0022] (11) As an embodiment of the present disclosure, in (10), the barrier layer uses a material with a larger band gap than the material of the first semiconductor layer.

[0023] (12) As an embodiment of this disclosure, in (10) or (11), the conductivity type of the potential barrier layer is different from that of the first semiconductor layer.

[0024] (13) As an embodiment of the present disclosure, in any one of (10) to (12), the barrier layer uses a material with a smaller band gap than the material of the substrate.

[0025] (14) As an embodiment of the present disclosure, in any one of (10) to (13), the conductivity type of the potential barrier layer is different from that of the substrate.

[0026] (15) As an embodiment of the present disclosure, in any one of (1) to (14), the first semiconductor layer is in direct contact with the active layer, and the band gap of the material of the layer in the first semiconductor layer that is in contact with the active layer is larger than that of the active layer.

[0027] (16) As an embodiment of the present disclosure, in any of (1) to (15), the second semiconductor layer is in direct contact with the active layer, and the band gap of the material of the layer in the second semiconductor layer that is in contact with the active layer is larger than that of the active layer.

[0028] (17) As an embodiment of the present disclosure, in any one of (1) to (16), the side from which the infrared rays are emitted or incident is of an n-type conductivity type.

[0029] (18) A method for manufacturing an infrared device according to an embodiment of the present disclosure includes: stacking a sacrificial layer and a semiconductor stack film on a substrate; removing the sacrificial layer; forming a barrier layer made of an amorphous substance or polymer on a substrate different from the substrate; bonding the semiconductor stack film on the barrier layer; and etching the semiconductor stack film to form a semiconductor stack portion. The manufactured infrared device includes: the substrate; the semiconductor stack portion disposed on the substrate and having a first semiconductor layer, an active layer, and a second semiconductor layer; and a barrier layer located between the substrate and the semiconductor stack portion to suppress leakage current. The side of the substrate on which the semiconductor stack portion is disposed is designated as a reference surface. The first angle formed by the side of the first semiconductor layer and the surface parallel to the reference surface and the second angle formed by the side of the barrier layer and the surface parallel to the reference surface are different. The side of the first semiconductor layer is in contact with the side of the barrier layer.

[0030] Utility Model Effect

[0031] According to this disclosure, a high-performance infrared device and a method for manufacturing an infrared device can be provided. Attached Figure Description

[0032] Figure 1 This is a diagram illustrating a structural example of an infrared device according to an embodiment of the present disclosure;

[0033] Figure 2 This is a diagram illustrating another structural example of an infrared device;

[0034] Figure 3 This is a diagram illustrating another structural example of an infrared device;

[0035] Figure 4 This is a diagram illustrating another structural example of an infrared device;

[0036] Figure 5 This is a partial cross-sectional view of an infrared device, showing an example of the angles of the side of the first semiconductor layer and the side of the barrier layer.

[0037] Figure 6 It is a partial cross-sectional view of an infrared device, a diagram used to illustrate the angle of the side of the potential barrier layer.

[0038] Figure 7 It is a diagram used to illustrate the thickness of the semiconductor stack in the stacking direction.

[0039] Figure 8 This is a partial cross-sectional view of an infrared device, showing an example of the angles of the side of the first semiconductor layer and the side of the barrier layer.

[0040] Figure 9 It is a partial cross-sectional view of an infrared device, a diagram used to illustrate the angle of the side of the potential barrier layer.

[0041] Figure 10A This is a diagram illustrating a method for manufacturing an infrared device according to an embodiment of this disclosure.

[0042] Figure 10B This is a diagram illustrating a method for manufacturing an infrared device according to an embodiment of this disclosure.

[0043] Figure 10C This is a diagram illustrating a method for manufacturing an infrared device according to an embodiment of this disclosure.

[0044] Figure 10D This is a diagram illustrating a method for manufacturing an infrared device according to an embodiment of this disclosure.

[0045] Figure 10E This is a diagram illustrating a method for manufacturing an infrared device according to an embodiment of this disclosure.

[0046] Figure 11 This is a diagram used to illustrate the difference in light reflection caused by the relationship between the side surface of the first semiconductor layer and the side surface of the potential barrier layer.

[0047] Figure 12 This is a diagram used to illustrate the difference in light reflection caused by the relationship between the side surface of the first semiconductor layer and the side surface of the potential barrier layer.

[0048] Figure 13 This is a partial cross-sectional view of an infrared device, showing an example of the angles of the side of the first semiconductor layer and the side of the barrier layer.

[0049] Figure 14 This is a partial cross-sectional view of an infrared device, and is another example of the angles of the side of the first semiconductor layer and the side of the barrier layer.

[0050] Label Explanation

[0051] 10 substrates

[0052] 20 Semiconductor Stack

[0053] 21 First semiconductor layer

[0054] 23 Active Layer

[0055] 25 Second semiconductor layer

[0056] 30 electric barrier layers

[0057] 31 First protective film

[0058] 32 Second protective film

[0059] 50 electrode section Detailed Implementation

[0060] <Infrared Devices>

[0061] Figure 1 This is a diagram illustrating a structural example of an infrared device according to an embodiment of the present disclosure. The infrared device of this embodiment may have a wavelength λ... p The optical characteristics of an infrared device have peak values. The optical characteristics of an infrared device can have multiple peak values. For example, wavelength λ... p It can be any one of multiple peaks in optical characteristics. The infrared device includes a substrate 10, a semiconductor stack 20, and a barrier layer 30. In the semiconductor stack 20, the side of the substrate 10 where the semiconductor stack 20 is disposed is designated as a reference plane. The first angle formed by the side surface of the first semiconductor layer 21 and the plane parallel to the reference plane is different from the second angle formed by the side surface of the barrier layer 30 and the plane parallel to the reference plane. Furthermore, the side surface of the first semiconductor layer 21 is in contact with the side surface of the barrier layer 30.

[0062] Here, infrared device refers to either infrared light-emitting element or infrared light-receiving element, which is a general term encompassing both. The infrared light-emitting element is implemented using the structure described below, and the infrared light-receiving element is implemented using the same structure. Specifically, when the infrared device is an infrared light-emitting element, it can be a light-emitting diode (LED). Furthermore, when the infrared device is an infrared light-receiving element, it can specifically be a photodiode (PD).

[0063] <Substrate>

[0064] The infrared device of this embodiment includes a substrate 10. The substrate 10 is not particularly limited as long as it is a substrate supporting the semiconductor stack 20. Examples include GaAs substrates, InP substrates, GaN substrates, Si substrates, quartz substrates, aluminum substrates, oxide substrates, aluminum nitride substrates, and flexible polyimide substrates. For example, the substrate 10 can be a Si-based substrate containing IC circuitry.

[0065] In the infrared device of this embodiment, the current leaking from the semiconductor stack 20 to the substrate 10 (hereinafter referred to as "leakage current") can be suppressed by the potential barrier layer 30. Leakage current can be further suppressed by using a substrate 10 with a low impurity concentration (carrier concentration) or a semi-insulating substrate 10. Furthermore, in the mid-infrared long-wavelength region, free electron absorption of electrons or holes may become significant. For example, by using a substrate 10 with a low impurity concentration or a semi-insulating substrate 10, the effect of suppressing free electron absorption can be improved.

[0066] Here, Figure 1 The reference surface 10a shown is the side of the substrate 10 on which the semiconductor stack 20 is provided.

[0067] <Semiconductor stack>

[0068] The infrared device of this embodiment includes a semiconductor stack 20 disposed on a substrate 10. The semiconductor stack 20 has a first semiconductor layer 21, an active layer 23, and a second semiconductor layer 25 from the substrate 10 side. The first semiconductor layer 21 and the second semiconductor layer 25 are directly connected to the active layer 23. The semiconductor stack 20 and the electrode portion 50 constitute a unit element. Multiple semiconductor stacks 20 may also be present. In this case, if the infrared device is an infrared light-emitting element, multiple unit elements can be connected in series or parallel to obtain the desired luminous intensity and to achieve appropriate driving voltage and current. In this embodiment, the unit element constitutes a light-emitting diode. Furthermore, if the infrared device is an infrared light-receiving element, a manageable resistance value can be achieved when amplifying the output signal through an amplification circuit, thus allowing multiple unit elements to be connected in series or parallel. In this embodiment, the unit element constitutes a photodiode.

[0069] In the following description, the direction in which the first semiconductor layer 21, the active layer 23, and the second semiconductor layer 25 are stacked on the substrate 10 is sometimes referred to as the "stack direction". In this embodiment, the stack direction is orthogonal to the reference plane 10a.

[0070] <First Semiconductor Layer>

[0071] The first semiconductor layer 21 is a semiconductor layer of a first conductivity type. In this embodiment, the first conductivity type is n-type. Materials used to construct the first semiconductor layer 21 include, but are not limited to, InSb, GaAs, InAs, InGaAs, InAlSb, GaAsSb, or InGaP. Furthermore, the first semiconductor layer 21 can be composed of a stacked structure of multiple materials. The aforementioned materials are doped with impurities to control the impurity concentration (carrier concentration).

[0072] Here, impurities such as Sn and Te are used as n-type doping materials, and Zn, Be, and Ge are used as p-type doping materials. Additionally, Si is used as an n-type or p-type doping material depending on the semiconductor of the parent material. However, the impurity materials are not limited to these. The impurity concentration can be evaluated, for example, by secondary ion mass spectrometry (SIMS). Furthermore, the first semiconductor layer 21 is preferably doped into n-type or p-type by donor or acceptor impurities, but it may also be undoped as long as it has a first conductivity type. Additionally, the first semiconductor layer 21 may include a dislocation filtering layer. Furthermore, the first semiconductor layer 21 may be composed of multiple layers. Here, when the first semiconductor layer 21 is in direct contact with the active layer 23, from the viewpoint of reducing diffusion current, the material of the layer in the first semiconductor layer 21 that is in contact with the active layer 23 preferably has a larger bandgap than the active layer 23.

[0073] <Active Layer>

[0074] The active layer 23 is a light-emitting layer or a light-receiving layer. Materials used for the active layer 23 include, but are not limited to, InAsSb, etc. Here, the active layer 23 can be an intrinsic semiconductor or be doped to p-type. Especially in cases with narrow band gaps, the active layer 23 is sometimes lightly doped to p-type. As an example of light doping, 10... 16 / cm 3 Up to 10 18 / cm 3 Impurities are present.

[0075] <Second Semiconductor Layer>

[0076] The second semiconductor layer 25 is a semiconductor layer of a second conductivity type. The second conductivity type can be a different type from the first conductivity type, or it can be the same type. In this embodiment, the second conductivity type is p-type, different from the first conductivity type. As another example, the first conductivity type can be p-type, and the second conductivity type can be n-type. As the constituent material of the second semiconductor layer 25, InSb, GaAs, InAs, InGaAs, InAlSb, GaAsSb, or InGaP are used, but the method is not limited to these. Furthermore, the second semiconductor layer 25 can be composed of a stacked structure of multiple materials. Here, when the second semiconductor layer 25 is in direct contact with the active layer 23, from the viewpoint of reducing diffusion current, the material of the layer in the second semiconductor layer 25 that is in contact with the active layer 23 preferably has a larger bandgap than the active layer 23. Additionally, the emission direction of infrared radiation in the light-emitting element or the incident direction of infrared radiation in the light-receiving element can be either vertical or horizontal on the substrate 10. From the perspective of the increased infrared transmittance brought about by the Burstein-Moss effect of infrared elements, it is preferable that the side from which infrared rays are emitted or incident is of an n-type conductivity type.

[0077] <Electrode Section>

[0078] The electrode portion 50 is preferably made of a material with high reflectivity in the mid-infrared long-wavelength region. For example, Au and Al can be used as the material for the electrode portion 50. Furthermore, to reduce contact resistance, improve adhesion, and prevent interdiffusion between the electrode material and the semiconductor material, different electrode materials can be stacked on top of each other in the electrode portion 50. For example, Ti, Pt, Ni, Cr, and Cu can also be used. However, the electrode material is not limited to these.

[0079] The electrode portion 50 is electrically bonded (contacted) with the first semiconductor layer 21 in a first portion, and current is injected or extracted relative to the first semiconductor layer 21. The electrode portion 50 is electrically bonded (contacted) with the second semiconductor layer 25 in a second portion, and current is injected or extracted relative to the second semiconductor layer 25.

[0080] <Electric potential barrier layer>

[0081] The barrier layer 30 is located between the substrate 10 and the semiconductor stack 20, which helps to increase the resistance between the substrate 10 and the semiconductor stack 20. By suppressing leakage current through the barrier layer 30, a high-performance infrared device can be realized without reducing the luminous intensity or detection sensitivity. From the viewpoint of insulation, the thickness of the barrier layer 30 in the stacking direction is preferably 500 nm or more.

[0082] The barrier layer 30 can be an amorphous or polymeric layer. For example, the barrier layer 30 can be a layer of silicon nitride (SiN), silicon dioxide (SiO2), aluminum oxide (Al2O3), heated silicon nitride, silicone, silicon monoxide (SiO), epoxy resin, or polyimide. When the material of the barrier layer 30 is an amorphous or polymeric layer, a pre-formed semiconductor stack 20 is connected to the substrate 10 via the barrier layer 30, and adjacent semiconductor stacks 20 are connected via electrode portions 50, thereby fabricating an infrared device.

[0083] Here, when the material of the barrier layer 30 is an amorphous substance or polymer, it is difficult to form a semiconductor stack 20 on the barrier layer 30 using MBE (molecular beam epitaxy) or MOCVD (metal-organic chemical vapor deposition). MBE and MOCVD are methods for growing crystals by inheriting the crystal information of the layer that serves as the substrate. This is because the amorphous substance or polymer that serves as the substrate is non-crystalline and therefore does not contain crystal information (orientation, atomic spacing, etc.). A method for manufacturing an infrared device according to an embodiment of this disclosure is as follows. First, on a substrate a (refer to) different from the substrate 10... Figure 10A The sacrificial layer b to be removed after stacking (see reference) Figure 10B ), thereby forming a semiconductor multilayer film X (refer to Figure 10C Examples of methods for forming this layer include MBE or MOCVD. Next, the sacrificial layer b is removed, and only the semiconductor stack film X is peeled off. The semiconductor stack film X is then bonded to the substrate 10 via the barrier layer 30 (see reference). Figure 10D Here, bonding to the substrate 10 is performed, for example, by lamination. Methods for removing the sacrificial layer b include etching. Methods for bonding the barrier layer 30 and the semiconductor laminate X include atomic diffusion bonding or surface activation. The surface of the semiconductor laminate X that bonds to the substrate 10 can be the surface c that contacts the sacrificial layer b, or the surface d opposite to the surface c that contacts the sacrificial layer b. Thus, a structure e in which the barrier layer 30 and the semiconductor laminate X are stacked on the substrate 10 can be formed (see reference). Figure 10E Next, by appropriately etching the semiconductor stack film X of structure e, a semiconductor stack 20 can be formed. The layer used in the mask during this etching can be directly used as a protective layer for the infrared device. Then, by appropriately forming the protective layer, adjacent semiconductor stacks 20 are connected by electrode portions 50, thereby manufacturing an infrared device.

[0084] Alternatively, the barrier layer 30 can be a semiconductor layer. In this case, the infrared device is manufactured using known semiconductor manufacturing methods. When the material of the barrier layer 30 is semiconductor, to make leakage current flow difficult, the barrier layer 30 can use a material with a larger band gap than the material of the first semiconductor layer 21. By forming a barrier in a larger material relative to a material with a smaller band gap, the inflow of charge carriers from the first semiconductor layer 21 with a smaller band gap to the barrier layer 30 with a larger band gap is restricted, thereby reducing leakage current. Here, the barrier layer 30 can use a material with a smaller band gap than the material of the substrate 10. This restricts the inflow of charge carriers from the barrier layer 30 with a smaller band gap to the substrate 10 with a larger band gap, reducing leakage current. Furthermore, the conductivity type of the barrier layer 30 can be different from that of the first semiconductor layer 21. This is because forming a barrier in a different conductivity type restricts the inflow of charge carriers, thereby reducing leakage current.

[0085] Here, as Figure 2 As shown, the region between the semiconductor stacked portions 20 is the "first region," and the region not in the first region is the "second region." In other words, the second region is the region where the main components of the aforementioned unit elements are formed, and the connection region between adjacent unit elements is the first region. A barrier layer 30 is at least disposed in the second region. Figure 2 As shown, the electric barrier layer 30 may not exist in the first region. As another example, such as... Figure 3 As shown, the electric barrier layer 30 can be formed to exist in the first region. Furthermore, as... Figure 4As shown, a potential barrier layer 30 exists in the first region and can be formed to separate the first protective film 31. Here, the first protective film 31 is a film formed on the side and top surfaces of the semiconductor stack 20 to protect the semiconductor stack 20. For example, silicon oxide, silicon nitride, aluminum oxide, titanium oxide, zinc oxide, hafnium oxide, etc., can be selected as the first protective film 31. Alternatively, silicone resin, polyimide resin, epoxy resin, etc., can be selected. When the potential barrier layer 30 is also formed in the first region, the coverage becomes better, thereby further enhancing the effect of suppressing leakage current.

[0086] Here, the first protective film 31 can be formed to directly contact the side and top surfaces of the semiconductor stack 20, or it can be formed to contact through the second protective film 32. Figure 2 The infrared device has a second protective film 32, and the structure of the potential barrier layer 30 is the same as that of the infrared device. Figure 1 correspond.

[0087] In addition, such as Figure 3 As shown, a potential barrier layer 30 exists in the first region, and it can be formed such that the thickness (h1) of the potential barrier layer 30 in the stacking direction in the first region is thinner than the thickness (h2) of the potential barrier layer 30 in the stacking direction in the second region. In this case, since the thickness of the potential barrier layer 30 changes at the boundary between the first and second regions, the distance along the surface of the potential barrier layer 30 (creep distance) can be extended. By extending the creepage distance, the ESD (Electrostatic Discharge) resistance with adjacent unit elements can be improved. Here, as... Figure 4 As shown, the potential barrier layer 30 can be formed to divide the first protective film 31.

[0088] In addition, it is preferable to extend the creepage distance for the side portion of the semiconductor stack 20. Figure 5 This is a partial cross-sectional view of an infrared device, showing an example of the angles of the side surfaces of the first semiconductor layer 21 and the barrier layer 30. The first angle (θ1) formed by the side surface of the first semiconductor layer 21 and the surface parallel to the reference plane 10a, and the second angle (θ2) formed by the side surface of the barrier layer 30 and the surface parallel to the reference plane 10a, are different; the second angle can be greater than the first angle. By making the first angle different from the second angle, the creepage distance of the side surface portion of the first semiconductor layer 21 can be extended compared to the case where the first angle and the second angle are the same. Extending the creepage distance further improves the ESD (electrostatic discharge) resistance to adjacent unit elements or other components on the same substrate. The second angle may not be perpendicular to the reference plane 10a. Here, as... Figure 6 As shown, when the barrier layer 30 has a thin portion in the stacking direction, the second angle is determined except for the thin portion. Furthermore, as... Figure 8 and Figure 9 As shown, the second angle can be smaller than the first angle. When the second angle is smaller than the first angle, the adhesion to the first semiconductor layer 21 and the barrier layer 30 can be improved when electrodes and protective layers are further formed on the first semiconductor layer 21 and the barrier layer 30. Here, when the angles of the side surfaces of the first semiconductor layer 21 or the barrier layer 30 are not all the same and have multiple angles, any one of the angles of the side surfaces of the first semiconductor layer 21 and the barrier layer 30 can be different from other structures. For example, as... Figure 13 As shown, when the side surface of the first semiconductor layer 21 has angles θ1 and θ1′ relative to the reference plane, it is acceptable as long as either angle θ1 or θ1′ is different from the angle θ2 of the side surface of the barrier layer 30.

[0089] Furthermore, when the angles of the side surfaces of the first semiconductor layer 21 or the barrier layer 30 are not all the same and have multiple angles, it can be a structure in which any one of the angles of the side surfaces of the first semiconductor layer 21 and the barrier layer 30 is different from the others, and any one of the angles of the side surfaces of the first semiconductor layer 21 and the barrier layer 30 is the same as the others, for example, as shown in the example. Figure 14 As shown, when the side surface of the potential barrier layer 30 has angles θ2 and θ2′ relative to the reference plane, the angle θ2 may be the same as the side surface θ1 of the first semiconductor layer 21, and the angle θ2′ may be different from the side surface θ1 of the first semiconductor layer 21.

[0090] By having the side of the first semiconductor layer 21 in contact with the side of the barrier layer 30, optical properties can be improved compared to the case where the side of the first semiconductor layer 21 does not contact the side of the barrier layer 30. For example, in the case where the infrared device is an infrared light-receiving element, when light perpendicular to the reference plane 10a is incident on the substrate from the substrate 10 side, if the side of the first semiconductor layer 21 does not contact the side of the barrier layer 30, the light is not reflected and leaks to the outside of the infrared light-receiving element. Therefore, the amount of light reaching the active layer 23 is reduced, which is not preferable. Figure 11 On the other hand, when the side of the first semiconductor layer 21 is in contact with the side of the barrier layer 30, light is reflected by either the side of the first semiconductor layer 21 or the side of the barrier layer 30, which can increase the amount of light reaching the active layer 23. Figure 12 ).

[0091] In this embodiment, the refractive index of the barrier layer 30 can be lower than the average refractive index of the semiconductor stack 20. For example, the average refractive index of the semiconductor stack 20 can be 3 to 4, and the refractive index of the barrier layer 30 can be less than 1.5. Additionally, the refractive index of the substrate 10 can be, for example, 3 to 4. Furthermore, the electrode (part of the electrode portion 50) on the upper surface of the semiconductor stack 20 functions as a reflector, thus enabling the infrared device to achieve a resonant structure and thus providing a wavelength λ. p The optical characteristic has a peak value at [nm]. Here, in the case of application to a gas sensor, the peak value corresponds to the absorption of a specific gas (having the function of a so-called filter). The half-width of the optical characteristic with the peak value (in other words, the emission spectrum or the photosensitive spectrum) is preferably 2 μm or less, and more preferably 1 μm or less. Here, it is possible to set a structure with multiple peak values ​​in a way that is sensitive to a variety of gases. In addition, in order to effectively generate a resonance effect, it is preferable to incident light or emitted light from the substrate side. In addition, it is preferable that the proportion of the area of ​​the upper surface of the semiconductor stack 20 covered by the electrode is high. This proportion is preferably 50% or more, and more preferably 75% or more. When the thickness of the semiconductor stack 20 in the stacking direction is set to t [nm], and integers greater than or equal to 0 are set to m, the following equation (1) is satisfied.

[0092] [Formula 2]

[0093]

[0094] In detail, if the average refractive index of the semiconductor stack 20 is set to "n", the thickness (t) of the semiconductor stack 20 in the stacking direction is calculated by the following equation (2).

[0095] [Formula 3]

[0096]

[0097] Here, the average refractive index refers to the average value obtained by weighting the refractive indices of each layer in the semiconductor stack by the film thickness. Figure 7 The thickness of the semiconductor stack 20 in the stacking direction and the magnitude of the light energy (|E|) enclosed inside the resonant structure represent the relationship between the thickness of the semiconductor stack 20 in the stacking direction and the magnitude of the light energy (|E|). 2 The relationship between ) and ). In a resonant structure, such as Figure 7 As shown, the fixed end is located at the interface between the metal and semiconductor stack 20, and the free end is located at the interface between the semiconductor stack and the barrier layer 30. The thickness t and wavelength λ of the semiconductor stack 20 in the stacking direction are... pThe relationship satisfies equation (2). Here, by confining the energy of light to a narrow region, the luminous intensity or photosensitive sensitivity can be improved. Therefore, m in equation (2) is preferably 3 or less, and more preferably 2 or less. On the other hand, from the viewpoint of controllability of etching (the viewpoint of exposing the first semiconductor layer 21 or the second semiconductor layer 25), m in equation (2) is preferably 0 or more, and more preferably 1 or more. In addition, by substituting the average refractive index (3 to 4) of the semiconductor stack 20 in this embodiment into equation (2), equation (1) is obtained. The infrared device of this embodiment can have a wavelength λ at the desired wavelength by designing the thickness of the stacked structure, etc., in a manner that satisfies equation (1). p It has optical properties with peak values.

[0098] The embodiments have been described above based on the accompanying drawings and examples. However, it should be noted that those skilled in the art can easily make various modifications and alterations based on this disclosure. Therefore, it should be understood that these modifications and alterations are included within the scope of this disclosure. For example, the functions included in each component, unit, etc., can be reconfigured in a logically consistent manner, and multiple units, etc., can be combined into one or divided.

Claims

1. An infrared device, characterized in that, The infrared device includes: substrate; A semiconductor layer stack is disposed on the substrate and includes a first semiconductor layer, an active layer, and a second semiconductor layer; and An electric barrier layer, located between the substrate and the semiconductor layer stack, suppresses leakage current. The side of the substrate where the semiconductor stack is located is designated as the reference surface. The first angle formed by the side surface of the first semiconductor layer and the surface parallel to the reference plane is different from the second angle formed by the side surface of the potential barrier layer and the surface parallel to the reference plane. The side of the first semiconductor layer is in contact with the side of the potential barrier layer.

2. The infrared device according to claim 1, characterized in that, The semiconductor stack consists of multiple layers, which are connected in series.

3. The infrared device according to claim 1 or 2, characterized in that, The potential barrier layer is an amorphous or polymeric layer.

4. The infrared device according to claim 3, characterized in that, The potential barrier layer is a layer of silicon nitride, silicon dioxide, aluminum oxide, heated silicon nitride, silicone, silicon monoxide, epoxy resin, or polyimide.

5. The infrared device according to claim 1 or 2, characterized in that, The potential barrier layer exists in a region, namely a first region, between the plurality of semiconductor stacks, and the thickness of the potential barrier layer in the stacking direction in the first region is thinner than the thickness of the potential barrier layer in the stacking direction in the second region, which is not the first region.

6. The infrared device according to claim 1 or 2, characterized in that, The second angle is not perpendicular to the reference plane.

7. The infrared device according to claim 1 or 2, characterized in that, The thickness of the potential barrier layer in the stacking direction is 500 nm or more.

8. The infrared device according to claim 1 or 2, characterized in that, The refractive index of the potential barrier layer is lower than the average refractive index of the semiconductor stack.

9. The infrared device according to claim 1 or 2, characterized in that, The infrared device has the optical characteristic of having a peak at wavelength λp [nm]. When the thickness of the semiconductor stack in the stacking direction is set to t [nm], and integers greater than or equal to 0 are set to m, the following equation (1) is satisfied: [Formula 1] 10. The infrared device according to claim 1 or 2, characterized in that, The potential barrier layer is a semiconductor layer.

11. The infrared device according to claim 10, characterized in that, The barrier layer uses a material with a larger bandgap than the material of the first semiconductor layer.

12. The infrared device according to claim 10, characterized in that, The conductivity type of the potential barrier layer is different from that of the first semiconductor layer.

13. The infrared device according to claim 10, characterized in that, The potential barrier layer uses a material with a smaller bandgap than the material of the substrate.

14. The infrared device according to claim 10, characterized in that, The conductivity type of the potential barrier layer is different from that of the substrate.

15. The infrared device according to claim 1 or 2, characterized in that, The first semiconductor layer is in direct contact with the active layer, and the band gap of the material in the first semiconductor layer that is in contact with the active layer is larger than that of the active layer.

16. The infrared device according to claim 1 or 2, characterized in that, The second semiconductor layer is in direct contact with the active layer, and the band gap of the material in the second semiconductor layer that is in contact with the active layer is larger than that of the active layer.

17. The infrared device according to claim 1 or 2, characterized in that, The side from which infrared light is emitted or incident is of the n-type conductivity type.

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