Radiation-Emitting Semiconductor Body and Method for Producing Same

Abstract

In an embodiment a radiation emitting semiconductor body includes a first semiconductor region of a first conductivity type, a second semiconductor region of a second conductivity type and an active region located between the first semiconductor region and the second semiconductor region, wherein the active region comprises InGaAlP, wherein the first conductivity type is n-conductive and the second conductivity type is p-conductive, wherein the active region has a larger band gap in an edge region of the semiconductor body than in a central region of the semiconductor body, and wherein a band gap of the second semiconductor region in the edge region and in the central region is the same.

Claims

1.-16. (canceled)

17. A radiation emitting semiconductor body comprising: a first semiconductor region of a first conductivity type; a second semiconductor region of a second conductivity type; and an active region located between the first semiconductor region and the second semiconductor region, wherein the active region comprises InGaAlP, wherein the first conductivity type is n-conductive and the second conductivity type is p-conductive, wherein the active region has a larger band gap in an edge region of the semiconductor body than in a central region of the semiconductor body, and wherein a band gap of the second semiconductor region in the edge region and in the central region is the same.

18. The radiation emitting semiconductor body according to claim 17, wherein a density of a first dopant in a transition region of the semiconductor body between the edge region and the central region decreases continuously in lateral directions, and wherein a width of the transition region is at most as large as a thickness of the active region.

19. The radiation emitting semiconductor body according to claim 18, wherein the active region in the central region is free of the first dopant.

20. The radiation emitting semiconductor body according to claim 17, wherein a first dopant comprises a p-doping material.

21. The radiation emitting semiconductor body according to claim 17, wherein the second semiconductor region comprises a second dopant.

22. The radiation emitting semiconductor body according to claim 21, wherein the second dopant and a first dopant are the same.

23. The radiation emitting semiconductor body according to claim 17, wherein the second semiconductor region is free of a first dopant.

24. The radiation emitting semiconductor body according to claim 23, wherein the active region is free of a second dopant.

25. The radiation emitting semiconductor body according to claim 17, wherein the band gap of the active region in the edge region is larger than in the central region by at least 50 meV to at most 150 meV.

26. A radiation emitting semiconductor chip comprising: the radiation emitting semiconductor body according to claim 17; a first contact layer arranged on the first semiconductor region; and a second contact layer arranged on the second semiconductor region.

27. The radiation emitting semiconductor chip according to claim 26, wherein the second contact layer is arranged on a carrier.

28. A method for producing a radiation emitting semiconductor body comprising: providing a first semiconductor region having a first conductivity type, wherein the first conductivity type is n-conductive and a second conductivity type is p-conductive; applying an active region on the first semiconductor region, wherein the active region comprises InGaAlP; increasing a band gap of the active region in an edge region of the semiconductor body, wherein the band gap is increased by doping the edge region; and applying a second semiconductor region having the second conductivity type after doping the active region.

29. The method according to claim 28, wherein a first dopant is introduced into the active region in the edge region during doping of the active region.

30. The method according to claim 29, further comprising applying a mask to the active region before doping the active region such that the edge region is free of the mask.

31. The method according to claim 30, further comprising removing the mask before the second semiconductor region is applied.

32. The method according to claim 28, wherein the second semiconductor region is doped with a second dopant while applying the second semiconductor region.

33. A radiation emitting semiconductor body comprising: a first semiconductor region of a first conductivity type; a second semiconductor region of a second conductivity type; and an active region located between the first semiconductor region and the second semiconductor region, wherein the active region comprises InGaAlP, wherein the first conductivity type is n-conductive and the second conductivity type is p-conductive, wherein the active region has a larger band gap in an edge region of the semiconductor body than in a central region of the semiconductor body, wherein the active region comprises a first dopant in the edge region, and wherein a band gap of the second semiconductor region in the edge region and in the central region is the same.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0069] In the following, the radiation emitting semiconductor body, the radiation emitting semiconductor chip, and the method for producing a radiation emitting semiconductor body are explained in more detail with reference to exemplary embodiments and the accompanying Figures.

[0070] They show:

[0071] FIGS. 1 to 3 schematic sectional views of method stages in the production of a semiconductor body according to an exemplary embodiment,

[0072] FIG. 4 a schematic cross-sectional view of a radiation emitting semiconductor chip according to an exemplary embodiment.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0073] Elements that are identical, similar or have the same effect are given the same reference signs in the Figures. The Figures and the proportions of the elements shown in the Figures are not to be regarded as to scale. Rather, individual elements can be shown exaggeratedly large for better representability and/or for better comprehensibility.

[0074] In the method according to the exemplary embodiment of the FIGS. 1, 2 and 3, a first semiconductor region 2 having a first conductivity type is provided according to FIG. 1. The first semiconductor region 2 is formed, for example, n-doped. Further, the first semiconductor region 2 is epitaxially formed on a substrate 12, for example. In particular, the substrate 12 is a growth substrate of the first semiconductor region 2.

[0075] In a further step, an active region 4 is applied, in particular over the entire surface, to the first semiconductor region 2. In addition, a barrier layer 8 is applied, in particular over the entire surface, to the active region 4. For example, the active region 4 is applied epitaxially to the first semiconductor region 2. Furthermore, the barrier layer 8 is applied epitaxially to the active region 4, for example.

[0076] In addition, after the application of the barrier layer 8, an intermediate layer 9 is applied to the barrier layer 8, in particular over the entire surface. For example, the intermediate layer 9 is also applied epitaxially.

[0077] The active region 4 and the barrier layer 8 comprise in particular indium gallium aluminum phosphide and the intermediate layer 9 comprises in particular gallium arsenide. Furthermore, the first semiconductor region 2 comprises in particular indium aluminum phosphide.

[0078] Subsequently, the intermediate layer 9 is structured as shown schematically in FIG. 2. The intermediate layer 9 is structured, for example, by a lithographic process. After patterning, the patterned intermediate layer 9 exclusively covers a central region 6 and a transition region 7 of the semiconductor body 1 to be produced. That is, the barrier layer 8 is exposed by removing the intermediate layer 9 in an edge region 5 which completely surrounds the central region 6.

[0079] Subsequently, a further intermediate layer 10 can be applied, in particular over the entire surface, to the intermediate layer 9 in the central region 6. Alternatively, it is possible for the further intermediate layer 10 to be applied to the intermediate layer 9, in particular over the entire surface, before the intermediate layer 9 is patterned. In this case, the intermediate layer 9 and the further intermediate layer 10 are structured using a lithographic process, for example, so that the barrier layer 8 is exposed in an edge region 5.

[0080] The intermediate layer 9 and the further intermediate layer 10 form a mask 11. In a further step, the active region 4 is doped with a first dopant 13 in the edge region 5. Here, the mask 11 prevents diffusion of the first dopant 13 into the central region 6. However, it is possible that the first dopant 13 diffuses in lateral directions in regions under the mask 11 during this step.

[0081] In this case, the active region 4 in the edge region 5 has a density of the first dopant 13 that is greater than a density of the first dopant 13 in the central region 6. Thus, the active region 4 in the edge region 5 has a band gap that is approximately 80 meV greater than a band gap in the central region 6.

[0082] Since the first dopant 13 is also diffused in lateral directions in regions under mask 11, the density of the first dopant 13 in the active region 4 decreases continuously from the edge region 5 to the central region 6. The region into which the first dopant 13 is diffused under the mask 11 corresponds to a transition region 7. The transition region 7 is arranged in lateral directions between the edge region 5 and the central region 6.

[0083] A width of the transition region 7 is at most as large as a thickness of the active region 4 and a thickness of the barrier layer 8. That is, the first dopant 13 can diffuse into the active region 4 under the mask 11 in lateral directions at most as far as the active region 4 and the barrier layer 8 are thick.

[0084] In a further process step, shown schematically in FIG. 3, the mask 11 is removed by means of an etching process. The mask 11, in particular the intermediate layer 9 and the further intermediate layer 10, are removed in such a way that the barrier layer 8 is completely exposed.

[0085] Subsequently, a second semiconductor region 3 is applied to the exposed barrier layer 8, which has a second conductivity type. The second semiconductor region 3 is, for example, p-doped. In particular, the second semiconductor region 3 is applied epitaxially to the barrier layer 8. In addition, the second semiconductor region 3 is doped with a second dopant 14 during application.

[0086] For example, the first dopant 13 and the second dopant 14 are different from each other. In this case, the first dopant 13 can be formed with Zn and the second dopant 14 with Mg. In particular, the second semiconductor region 3 is then free of the first dopant 13.

[0087] Alternatively, the first dopant 13 and the second dopant 14 are the same. In this case, the first dopant 13 and the second dopant 14 are formed with Zn.

[0088] In the case where the dopants 13, 14 are different or the same, the second semiconductor region 3, unlike the active region 4, has a band gap that is the same in lateral directions and/or in vertical directions in the edge region 5 and in the central region 6.

[0089] After the second semiconductor region 3 is applied, a termination layer 15 for passivating the second semiconductor region 3 is also grown on the second semiconductor region 3. The termination layer 15 comprises, for example, a semiconductor material such as GaAs.

[0090] Subsequently, the substrate 12 can be detached from the first semiconductor region 2 (not shown here).

[0091] The radiation emitting semiconductor chip 16 according to the exemplary embodiment of FIG. 4 comprises a radiation emitting semiconductor body 1 produced, for example, by the method described in connection with FIGS. 1 to 3. The radiation emitting semiconductor body 1 includes a first semiconductor region 2, a second semiconductor region 3, and an active region 4 arranged between the first semiconductor region 2 and the second semiconductor region 3. In this case, a substrate 12, such as shown in connection with FIGS. 1 to 3, is removed from the first semiconductor region 2.

[0092] A first contact layer 17 is arranged on the first semiconductor region 2. Furthermore, a second contact layer 18 is arranged on the second semiconductor region 3.

[0093] In addition, the second contact layer 18 is arranged on a carrier 19. The second contact layer 18 is in electrically conductive contact with the carrier 19.

[0094] The features and exemplary embodiments described in connection with the Figures can be combined with each other according to further exemplary embodiments, even if not all combinations are explicitly described. Furthermore, the embodiments described in connection with the Figures can alternatively or additionally have further features according to the description in the general part.

[0095] The invention is not limited by the description on the basis of the exemplary embodiments. Rather, the invention encompasses any new feature as well as any combination of features, which in particular includes any combination of features in the patent claims, even if this feature or combination itself is not explicitly stated in the patent claims or exemplary embodiments.