Semiconductor body

Abstract

Semiconductor bodies (10) with: - an n-doped region (20), - an active area (60), and - a p-doped region (70), wherein - the active region (60) is located between the n-doped (20) and the p-doped region (70), - the n-doped region (20) comprises: - a first sequence of layers (30) which has pairs of alternating layers (31, 32), wherein - the first and second layers (31, 32) of each pair differ in their doping concentration, - the first and second layers (31, 32) of each pair have the same material composition except for their doping, and - a second layer sequence (50) which has pairs of alternating layers (51, 52), wherein - the first and second layers (51, 52) of each pair differ in their material composition, and - the second layer sequence (50) is arranged between the first layer sequence (30) and the active region (60), and wherein an n-doped intermediate layer (40) is arranged between the first layer sequence (30) and the second layer sequence (50), which has a higher dopant concentration than the first layers (31) of the first layer sequence (30), wherein the first layers (31) of the first layer sequence (30) are n-doped layers and have a higher dopant concentration than the second layers (32) of the first layer sequence (30), and the first layers (31) of the first layer sequence (30) have a dopant concentration of at most 1 * 10 18 1 / cm 3 exhibit.

Description

[0001] A semiconductor body is specified.

[0002] Examples of semiconductor bodies are described in documents US 8 536 615 B1, JP 2013 - 183 126 A, JP 2000 - 244 072 A, JP 2016 - 72 388 A, EP 2 360 745 A2 and JP 2013 187 484 A.

[0003] One problem to be solved is to specify a semiconductor body that can be operated efficiently. This problem is solved, among other things, by a semiconductor body with the features of the independent claim.

[0004] According to at least one embodiment of the semiconductor body, the semiconductor body comprises an n-doped region. The n-doped region is doped with at least one n-doping agent. The n-doped region can comprise one or more n-doped semiconductor layers. The n-doped region can be grown on a growth substrate and extend laterally over the entire growth substrate. The lateral directions are those directions that run parallel to a principal extension plane of the semiconductor body. The lateral directions are perpendicular to the vertical direction, which, for example, runs parallel to a stacking direction and / or a growth direction of the semiconductor body.

[0005] Furthermore, it is possible that the growth substrate is located away from the n-doped region. Additionally, the n-doped region can form a three-dimensional shape, such as a cuboid or cylinder. It is also possible that the n-doped region does not have a homogeneous doping concentration. That is, the doping concentration may be higher in some areas of the n-doped region than in others.

[0006] According to at least one embodiment, the semiconductor body comprises an active region. During operation, the active region performs a function of the semiconductor body. For example, the active region can be configured to emit or detect electromagnetic radiation. The semiconductor body is then part of an optoelectronic component. The active region can then, for example, comprise a plurality of alternately arranged quantum well layers and barrier layers.

[0007] Furthermore, it is possible that the semiconductor body is part of an electronic component such as a diode, a transistor, or an integrated circuit. The active area is then configured accordingly.

[0008] The active area may have grown on the n-doped area and extend laterally across the n-doped area.

[0009] According to at least one embodiment, the semiconductor body comprises a p-doped region, wherein the active region is arranged between the n-doped and the p-doped regions. The p-doped region is doped with at least one p-type dopant. The fact that the active region is arranged between the n-doped and p-doped regions can mean that the n-doped region, the active region, and the p-doped region are arranged vertically one above the other. The p-doped region can thus have grown on top of the active region and extend laterally across it. The p-doped region can be formed by a p-doped semiconductor layer.

[0010] According to at least one embodiment of the semiconductor body, the n-doped region comprises a first layer sequence, which has pairs of alternating layers, wherein the first and second layers of each pair differ in their doping concentration and the first and second layers of each pair have the same material composition except for their doping. The first layer sequence thus has a plurality of alternating first and second layers of the first layer sequence. The first and second layers of the first layer sequence are arranged vertically above one another.

[0011] In this process, either the doping concentration of the first layer is greater than the doping concentration of the second layer, or the doping concentration of the second layer is greater than the doping concentration of the first layer. This can mean, for example, that the first layer is doped and the second layer is nominally undoped. "Nominally undoped" here and in the following text means that no dopant is supplied during the growth of the second layer. However, the second layer can still have a doping concentration caused by diffusion of the dopant from the first layer into the second layer.

[0012] According to at least one embodiment of the semiconductor body, the n-doped region comprises a second layer sequence, which has pairs of alternating layers, wherein the first and second layers of each pair differ in their material composition. The second layer sequence thus has a plurality of alternating first and second layers. These are arranged vertically above one another. This means that the difference in the material compositions of the first and second layers is not only due to their dopant concentration, but also to the materials from which they are formed, apart from the dopants. At least one layer of each pair in the second layer sequence can be n-doped. It is also possible for all layers of the second layer sequence to be n-doped.

[0013] According to at least one embodiment of the semiconductor body, the second layer sequence is arranged between the first layer sequence and the active region. This means that the first layer sequence, the second layer sequence, and the active region are arranged vertically, one above the other. The second layer sequence can therefore be grown on top of the first layer sequence, and the active layer can be grown on top of the second layer sequence.

[0014] The semiconductor body can be grown on a substrate. It can be grown epitaxially on a substrate using metal-organic vapor deposition. Alternatively, the semiconductor body can be grown without a substrate and instead be located on a support structure that is subsequently attached to the semiconductor body after growth. In this case, the semiconductor body can be a thin-film semiconductor.

[0015] According to at least one embodiment of the semiconductor body, the semiconductor body comprises an n-doped region, an active region, and a p-doped region. The active region is located between the n-doped and the p-doped regions. The n-doped region comprises a first layer sequence, which has pairs of alternating layers, wherein the first and second layers of each pair differ in their dopant concentration and have the same material composition except for their doping. The n-doped region further comprises a second layer sequence, which has pairs of alternating layers, wherein the first and second layers of each pair differ in their material composition. The second layer sequence is located between the first layer sequence and the active region.Furthermore, an n-doped intermediate layer is arranged between the first layer sequence and the second layer sequence, which has a higher dopant concentration than the first layers of the first layer sequence, wherein the first layers of the first layer sequence are n-doped layers and have a higher dopant concentration than the second layers of the first layer sequence, and the first layers of the first layer sequence have a dopant concentration of at most 1 * 10. 18 1 / cm 3 exhibit.

[0016] The semiconductor body described here is based, among other things, on the understanding that the first layer sequence provides protection against electrostatic discharge. If the semiconductor body has this first layer sequence, the failure rate due to electrostatic charging is surprisingly significantly reduced. If the semiconductor body has a second layer sequence, the diffusion of dopants and other impurities into the active region can be prevented or reduced. Furthermore, the second layer sequence smooths out topographic irregularities in the underlying layers before the active region is grown onto it. By avoiding dopants and other impurities in the active region and by preventing topographic irregularities before the active region grows, the semiconductor body can be operated more efficiently.

[0017] According to at least one embodiment, the first layer of each pair in the first layer sequence is doped, and the second layer of each pair in the first layer sequence is nominally undoped. A semiconductor body with a first layer sequence containing doped and undoped layers can exhibit improved stability against electrostatic discharge compared to a semiconductor body with a layer sequence that is doped throughout. The failure rate due to electrostatic discharge can thus be significantly reduced.

[0018] According to at least one embodiment, the semiconductor body is based on a nitride compound semiconductor material. This means, in particular, that at least some of the regions of the semiconductor body are a nitride compound semiconductor material, preferably Al. n Ga m In 1-n-mN must contain or consist of, where 0 ≤ n ≤ 1, 0 ≤ m ≤ 1, and n+m ≤ 1. This material does not necessarily have to have a mathematically exact composition according to the formula above. Rather, it may, for example, contain one or more dopants as well as additional components. For the sake of simplicity, however, the formula above only includes the essential components of the crystal lattice (Al, Ga, In, N), even though these may be partially replaced and / or supplemented by small amounts of other substances.

[0019] The n-doped region of the semiconductor body can be partially formed with n-doped gallium nitride (GaN). Silicon is particularly commonly used as the n-doping material.

[0020] The active region can be formed, for example, with indium gallium nitride (InGaN) and GaN or indium gallium aluminum nitride (InGaAlN) and gallium aluminum nitride (GaAlN). Some of the layers in the active region can be n-doped. The p-doped region can, in particular, be formed with p-doped GaN.

[0021] The first and second layers of the first layer sequence can be formed with GaN. In any case, the first and second layers of the first layer sequence are formed with the same material, except for the dopant concentration in the layers.

[0022] The first layer of the second layer sequence can be made of InGaN, and the second layer of the second layer sequence can be made of GaN. Likewise, it is possible for the first layer of the second layer sequence to be made of GaN and for the second layer of the second layer sequence to be made of InGaN. In each case, the first and second layers of the second layer sequence are made of different materials. The growth substrate of the semiconductor body can, for example, be made of sapphire or silicon.

[0023] According to at least one embodiment, the n-doped region and the p-doped region are based on a nitride compound semiconductor material, and the first layer sequence is nominally free of indium. This means that the doped first layers of the first layer sequence can, in particular, be formed by GaN. The fact that the first layer sequence is nominally free of indium means that indium is not intentionally introduced during the growth of the first layer sequence. However, it is possible that indium from other regions of the semiconductor body partially diffuses into the first layer sequence and is present there in very low concentrations. For example, the proportion of indium around the semiconductor material of the first layer sequence is at most 5%, and in particular, at most 1%.

[0024] According to at least one embodiment, the active area is configured to generate or detect electromagnetic radiation, in particular light. The semiconductor body can, for example, be a light-emitting diode (LED). The LED can, for example, emit electromagnetic radiation in the ultraviolet, blue, or green spectral range. It is also possible for the LED to emit electromagnetic radiation in several of these spectral ranges.

[0025] According to at least one embodiment, the intermediate layer has a dopant concentration of at least 1 x 10 18 per cm 3The dopant can be, for example, silicon. If the intermediate layer has a higher dopant concentration than the first layer sequence, or at least as high a dopant concentration as the n-doped layers of the first layer sequence, the active region can be grown more effectively onto the underlying layers. This can mean that the second layer sequence is in better mechanical and electrical contact with the first layer sequence, and that the active region is also in better mechanical and electrical contact with the second layer sequence. In other words, the intermediate layer can reduce the electrical contact resistance between the first and second layer sequences, and the intermediate layer also serves as a mechanical connection between the two layer sequences.

[0026] According to at least one embodiment, the intermediate layer is topographically flat. This means that the intermediate layer has a particularly low roughness, which is lower than the roughness would be without the intermediate layer. Because the intermediate layer is topographically flat, the active region, which is grown on the second layer sequence, can also be grown on a topographically flat surface. This allows the semiconductor body to be operated more efficiently.

[0027] According to at least one embodiment, the thickness of the first layer of the first layer sequence is at least 1 nm and at most 30 nm, and the thickness of the second layer of the first layer sequence is at least 30 nm and at most 100 nm. This means that the layers have the specified thicknesses in the vertical direction. Preferably, the thickness of the first layer of the first layer sequence is at least 10 nm and at most 15 nm. Preferably, the thickness of the second layer of the first layer sequence is at least 40 nm and at most 60 nm. Due to the size of the layer thicknesses, the diffusion of dopants from the doped layers into the undoped layers can be reduced. This makes it possible for the dopants to diffuse essentially only into the edge regions of the undoped layers that border the doped layers.

[0028] According to at least one embodiment, the number of pairs in the first layer sequence is at least 1 and at most 10. This means that the first layer sequence has at least one and at most ten first layers and the same number of second layers as first layers. Preferably, the number of pairs in the first layer sequence is at least three and at most five. Advantageously, even with this small number of pairs in the first layer sequence, significantly increased stability against electrostatic discharge can be achieved. It is therefore possible to improve stability against electrostatic discharge without substantially increasing the thickness of the semiconductor body.

[0029] According to at least one embodiment, the first layer of the first layer sequence is, for example, doped with silicon.

[0030] According to at least one embodiment, the thickness of the second layer sequence is less than or equal to 50 nm. The thickness of the first and second layers of the second layer sequence can, for example, be a maximum of 5 nm. Preferably, the thickness of the first and second layers of the second layer sequence can be at least 0.5 nm and at most 2 nm. A layer thickness of less than or equal to 50 nm for the second layer sequence allows for the lowest possible forward voltage of the semiconductor body.

[0031] The semiconductor bodies described here are explained in more detail below in conjunction with an exemplary embodiment and the corresponding figures. Fig. Figure 1 shows a schematic cross-section through a semiconductor body. Fig. Figure 2 shows a schematic cross-section through a semiconductor body according to an exemplary embodiment. In Fig. Figure 3 shows the failure rate under electrostatic charging for two semiconductor bodies. In Fig. Figure 4 shows the dopant concentration of different layers of a semiconductor body.

[0032] Identical, similar, or similarly effective elements in the figures are marked with the same reference symbols. The figures and the relative sizes of the elements depicted within them are not to be considered to scale. Rather, individual elements may be exaggerated for clarity and / or to improve representation.

[0033] Fig. Figure 1 shows a schematic cross-section through a semiconductor body 10. The semiconductor body 10 has an n-doped region 20. The n-doped region 20 can be located on a growth substrate or a support element. The n-doped region 20 has an n-contact layer 21.

[0034] In a vertical direction z, an n-doped intermediate layer 22 is arranged on the n-contact layer 21. The n-doped intermediate layer 22 and the n-contact layer 21 can be formed from n-doped GaN.

[0035] A second layer sequence 50 is arranged on the intermediate layer 22. The second layer sequence 50 has pairs of alternating first and second layers 51, 52. In Fig. Figure 1 shows only one representative first layer 51 and one representative second layer 52 of the second layer sequence 50. The second layer sequence 50 can comprise a plurality of alternating first and second layers 51, 52. The first layer 51 of the second layer sequence 50 can be formed with InGaN and the second layer 52 of the second layer sequence 50 with GaN. An active region 60 is arranged on the second layer sequence 50. A p-doped region 70 is arranged on the active region 60.

[0036] In the semiconductor body 10, which is in Fig. As shown in Figure 1, the second layer sequence 50 prevents diffusion of dopants and other foreign atoms into the active region 60 and therefore the semiconductor body 10 can be operated more efficiently.

[0037] Fig. Figure 2 shows a schematic cross-section through a semiconductor body 10 according to an exemplary embodiment. The semiconductor body 10 has an n-doped region 20 and a p-doped region 70. The n-doped region 20 has an n-contact layer 21.

[0038] In the vertical direction z, a first layer sequence 30 is arranged on the n-contact layer 21. The first layer sequence 30 comprises pairs of alternating first layers 31 and second layers 32. The first layers 31 are n-doped with silicon, and the second layers 32 are nominally undoped. This means that the second layers 32 are not intentionally doped; however, dopants from the first layers 31 may diffuse into the second layers 32. The first layers 31 of the first layer sequence 30 have a dopant concentration of at most 1 × 10⁻⁶. 18 1 / cm 3The first and second layers 31, 32 of each pair thus differ in their doping concentration and, apart from their doping, have the same material composition. The n-contact layer 21 and the first layer sequence 30 can be formed with GaN. In this embodiment, the first layer sequence 30 comprises three pairs of first and second layers 31, 32.

[0039] In the vertical direction z, an intermediate layer 40 is arranged on the first layer sequence 30. The intermediate layer 40 can be formed with GaN and be n-doped with silicon with a dopant concentration of at least 1 × 10⁻⁶. 18 per cm 3 . Due to the high dopant concentration of the intermediate layer 40, an active region 60 with improved quality can be grown and the stability of the semiconductor body against electrostatic discharge is increased.

[0040] A second layer sequence 50 is arranged on the intermediate layer 40. The second layer sequence 50 comprises pairs of alternating first layers 51 and second layers 52. The first layers 51 of the second layer sequence 50 can be made of InGaN, and the second layers 52 of the second layer sequence 50 can be made of GaN. The first and second layers 51, 52 of each pair thus differ in their material composition. Fig. Figure 2 shows only one representative first layer 51 and one representative second layer 52 of the second layer sequence 50. The second layer sequence 50 can comprise a plurality of alternating first and second layers 51, 52. The layer thickness of the second layer sequence 50 is less than or equal to 50 nm.

[0041] The active region 60 is deposited on the second layer sequence 50. The second layer sequence 50 is thus located between the first layer sequence 30 and the active region 60. The active region 60 can, for example, comprise a multiple quantum well structure, which includes a plurality of alternating quantum well layers and barrier layers. The barrier layers can be made of GaAlN or GaN, and the quantum well layers can be made of InAlGaN or InGaN. The p-doped region 70 is located on the active region 60. The active region 60 is therefore located between the n-doped and the p-doped regions 20, 70.

[0042] By introducing the first layer sequence 30 into the semiconductor body 10, the stability against electrostatic discharge of the semiconductor body 10 can be increased. By introducing the second layer sequence 50 into the semiconductor body 10, the semiconductor body 10 can be operated more efficiently, since the diffusion of dopants and other impurities into the active region 60 is prevented or reduced by the second layer sequence 50.

[0043] In Fig. 3 is the failure rate under electrostatic charging for the semiconductor body 10, which is in Fig. 1 is shown, and the semiconductor body 10, which is in Fig. Figure 2 shows the failure rate in the 2 kV HBM (human body model) test, i.e., at a discharge of 2 kV. The x-axis on the left shows the failure rate for semiconductor body 10, which is located in Fig. Figure 1 shows the failure rate for semiconductor body 10, which is located in the semiconductor body. Fig. 2 is shown. For the semiconductor body 10 from Fig. For semiconductor body 1, the failure rate is approximately 90 percent. In contrast, the failure rate for semiconductor body 10 is [missing information]. Fig. 2 less than 10 percent. A difference between the semiconductor bodies 10 in the Fig. 1 and Fig. 2 consists in the fact that the semiconductor body 10 in Fig. In addition to the second layer sequence 50, the first layer sequence 30 is also present. By incorporating the first layer sequence 30, the failure rate due to electrostatic discharge can be significantly reduced in a surprisingly effective manner.

[0044] In Fig. Figure 4 shows the dopant concentration of various layers of an embodiment of the semiconductor body 10, as it is used, for example, in the Fig.Figure 2 shows the dopant concentration. The concentration was determined using secondary ion mass spectrometry. The y-axis represents the dopant concentration in cm³. 3 The graph shows the depth from which the secondary ions are detected, in nm, plotted on the x-axis. A depth of 0 nm corresponds to the surface of the semiconductor body 10. The peak around 250 nm refers to the intermediate layer 40, which has a dopant concentration of approximately 1 × 10⁻⁶. 19 1 / cm 3 The first layer sequence 30 is located between approximately 290 nm and 430 nm depth. Due to the small layer thicknesses of the first and second layers 31, 32 of the first layer sequence 30, they cannot be assigned to a specific layer in the spectrum. It can be seen that the first layer sequence 30 has a lower dopant concentration than the intermediate layer 40. Reference symbol list 10 semiconductor bodies 20 n-doped area 21 n-contact layer 22 Intermediate shift 30 first layer sequence 31 first layer of the first layer sequence 32 second layer of the first layer sequence 40 Intermediate shift 50 second shift sequence 51 first layer of the second layer sequence 52 second layer of the second layer sequence 60 active area 70 p-doped area z vertical direction

Claims

[1] Semiconductor body (10) with: - an n-doped region (20), - an active area (60), and - a p-doped region (70), wherein - the active region (60) is located between the n-doped (20) and the p-doped region (70), - the n-doped region (20) comprises: - a first sequence of layers (30) which has pairs of alternating layers (31, 32), wherein - the first and second layers (31, 32) of each pair differ in their doping concentration, - the first and second layers (31, 32) of each pair have the same material composition except for their doping, and - a second layer sequence (50) which has pairs of alternating layers (51, 52), wherein - the first and second layers (51, 52) of each pair differ in their material composition, and - the second layer sequence (50) is arranged between the first layer sequence (30) and the active region (60), and wherein an n-doped intermediate layer (40) is arranged between the first layer sequence (30) and the second layer sequence (50), which has a higher dopant concentration than the first layers (31) of the first layer sequence (30), wherein the first layers (31) of the first layer sequence (30) are n-doped layers and have a higher dopant concentration than the second layers (32) of the first layer sequence (30), and the first layers (31) of the first layer sequence (30) have a dopant concentration of at most 1 * 10 18 1 / cm 3 exhibit. [2] Semiconductor body (10) according to the preceding claim, wherein the number of pairs of the first layer sequence (30) is at least three and at most five. [3] Semiconductor body (10) according to one of claims 1 and 2, wherein the second layer (32) of each pair of the first layer sequence (30) is nominally undoped. [4] Semiconductor body (10) according to any one of claims 1 to 3, wherein the n-doped region (20) and the p-doped region (70) are based on a nitride compound semiconductor material and the first layer sequence (30) of the n-doped region is nominally free of indium. [5] Semiconductor body (10) according to any one of claims 1 to 4, wherein the active area (60) is configured for generating or detecting electromagnetic radiation, in particular light. [6] Semiconductor body (10) according to any one of claims 1 to 5, wherein the intermediate layer (40) has a dopant concentration of at least 1 * 10 18 1 / cm 3 exhibits. [7] Semiconductor body (10) according to claim 6, wherein the intermediate layer (40) is topographically flat. [8] Semiconductor body (10) according to any one of the preceding claims 1 to 7, wherein the layer thickness of the first layer (31) of the first layer sequence (30) is at least 1 nm and at most 30 nm and the layer thickness of the second layer (32) of the first layer sequence (30) is at least 30 nm and at most 100 nm. [9] Semiconductor body (10) according to any one of the preceding claims 1 and 3 to 8, wherein the number of pairs of the first layer sequence (30) is at least 1 and at most 10. [10] Semiconductor body (10) according to any one of the preceding claims 1 to 9, wherein the layer thickness of the second layer sequence (50) is less than or equal to 50 nm.

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