OPTOELECTRONIC DEVICE AND METHOD FOR MANUFACTURING

Abstract

The invention relates to an optoelectronic device, in particular a miniaturized light-emitting device, for example for use in a display. The optoelectronic device comprises a first semiconductor layer, a second semiconductor layer, an active layer arranged between the first and second semiconductor layers, and a first and a second contact surface. The first and second semiconductor layers and the active layer extend in a lateral direction that is substantially perpendicular to a growth direction of the first and second semiconductor layers and the active layer. A first section of the active layer is n-doped and forms a first region. A second section of the active layer is p-doped and forms a second region.A third section of the active layer separates the first and second regions laterally and is essentially undoped, forming a third region. The first contact region is electrically coupled to the first region, and the second contact region is electrically coupled to the second region.

Description

[0001] The present invention relates to an optoelectronic device, in particular a miniaturized light-emitting device, and to a method for manufacturing the optoelectronic device. BACKGROUND

[0002] Due to the high mobility of charge carriers, non-radiative recombination at the singulation / mesacant edges of light-emitting devices (LEDs) is a significant problem, especially for phosphide and arsenide LEDs. This problem becomes more pronounced as the LEDs become smaller, because the ratio between the perimeter of the LED's active zone (along which non-radiative recombination centers can occur) and the area of ​​the active zone configured for light emission increases with size. Thus, as the LED size decreases, the ratio of non-radiative recombination centers to the area of ​​the active zone increases, and consequently, the efficiency of the LEDs decreases.

[0003] Known methods for addressing this problem include, firstly, the local injection of charge carriers (e.g., microprisms) to enable recombination as far away as possible from the singulation / mesacants, and secondly, quantum well mixing in the boundary regions of the LED's active area to prevent the diffusion of charge carriers from the interior of the active area to the singulation / mesacants by widening the band gap. However, these known methods do not yet demonstrate sufficient effectiveness to increase the efficiency of LEDs, especially small LEDs, as desired.

[0004] The aim of the present application is therefore to provide an optoelectronic device, in particular a miniaturized light-emitting device, with improved efficiency and a method for its manufacture. SUMMARY OF THE INVENTION

[0005] These and other problems are solved by the subject matter of the independent claims. Features and further aspects of the proposed principle are described in the dependent claims.

[0006] The core of the invention is a horizontal / lateral separation of the n- and p-doping of the semiconductor layer stack of an LED, instead of the conventional vertical separation along the growth direction of the semiconductor layer stack. In particular, the active layer of the semiconductor layer stack is laterally separated into an n-doped region, an undoped region, and a p-doped region, thereby creating the necessary structure for charge carriers to diffuse laterally along the active layer from the respective p- or n-doped region. In conventional LEDs, however, the charge carriers diffuse vertically from the respective p- or n-doped regions into the active layer, and due to the high mobility of the charge carriers in, for example,Phosphides and arsenides also diffuse towards the centers of non-radiative recombination near the singulation / mesacants of the active layer of the light-emitting device, as these represent a potential minimum.

[0007] According to the invention, the p-doped and n-doped regions are spatially separated laterally, so that a pn junction forms laterally / horizontally, in which the electrons and holes diffuse laterally to each other. Thus, electrons and holes are only present together in the undoped center of the active layer (with the exception of portions of two lateral singulation / mesacants), and most of the singulation / mesacants are "shielded" by the p- and n-doped regions. Since electrons and holes are required for non-radiative recombination, it cannot occur in purely p-doped or purely n-doped regions. This significantly reduces the diffusion of electrons and holes into the interference sites for non-radiative recombination at the singulation / mesacants, which considerably decreases non-radiative recombination and thus increases the efficiency of the LED.

[0008] The proposed principle is particularly suitable for very small LEDs, especially micro-LEDs, since the volume of the active layer in the pn junction is much smaller than in a conventional implementation of larger LEDs. This would lead to extremely high current densities in the center of larger LEDs and thus to higher currents. However, the smaller the LED, the smaller the volume required for radiative recombination, and for small LEDs, the positive effect of shielding the singulation / mesacant edges predominates.

[0009] In one aspect, an optoelectronic device, in particular a miniaturized light-emitting device, is provided, comprising a first semiconductor layer, a second semiconductor layer, an active layer arranged between the first and second semiconductor layers, and first and second contact surfaces. The first and second semiconductor layers and the active layer extend in a lateral direction that is substantially perpendicular to a growth direction of the first and second semiconductor layers and the active layer. Furthermore, a first section of the active layer is n-doped and forms a first region, a second section of the active layer is p-doped and forms a second region, and a third section of the active layer separates the first and second regions in the lateral direction and is substantially undoped, forming a third region.Electrical contact of the optoelectronic device can be made via the first contact surface and the second contact surface, wherein the first contact surface is electrically coupled to the first area and the second contact surface is electrically coupled to the second area.

[0010] The semiconductor layers can consist of a semiconductor material, such as one from the III-V and / or II-VI group of semiconductor compounds. The first and / or second semiconductor layer can consist of, for example, indium gallium aluminum phosphite (InGaAlP) or indium gallium arsenide (InGaAs). Zinc (Zn) or magnesium (Mg) can be used as the p-type dopant, and tellurium (Te) as the n-type dopant.

[0011] In some embodiments, the active layer has a multi-quantum well structure, wherein the active layer in particular has a quantum well mixed band gap in the first and second regions, but with dopants of a different doping type.

[0012] In some embodiments, only two side faces of the optoelectronic device, in particular opposing side faces resulting from singulation / mesa etching, each exhibit a portion of the third region. The remaining side faces of the optoelectronic device, however, each exhibit a portion of the first or second region, but not the third region and thus no undoped portion of the active layer.

[0013] In some embodiments, the active layer in the first section is n-doped over its entire thickness along the growth direction, and / or the active layer in the second section is p-doped over its entire thickness along the growth direction. Specifically, the active layer in the first section is n-doped over its entire thickness along the growth direction, and the active layer in the second section is p-doped over its entire thickness along the growth direction. The active layer can, for example, be undoped only in the third region.

[0014] In some embodiments, the first region further comprises an n-doped portion of the first and / or second semiconductor layer adjacent to the first section of the active layer in the growth direction. In particular, portions of the first and / or second semiconductor layer above or below the first section of the active layer may also be n-doped. For example, n-doped portions of the first and / or second semiconductor layer may be n-doped along their entire thickness in the growth direction.

[0015] In some embodiments, the second region also includes a p-doped portion of the first and / or second semiconductor layer adjacent to the second active layer in the growth direction. In particular, portions of the first and / or second semiconductor layer above or below the second active layer may also be p-doped. For example, p-doped portions of the first and / or second semiconductor layer may be p-doped along their entire thickness in the growth direction.

[0016] In some embodiments, the first region further comprises an n-doped portion of the first semiconductor layer adjacent to the first section of the active layer in the growth direction, and the second region further comprises a p-doped portion of the first semiconductor layer adjacent to the second section of the active layer in the growth direction. The n-doped portion of the first semiconductor layer may, for example, be n-doped over its entire thickness along the growth direction, and the p-doped portion of the first semiconductor layer may, for example, be p-doped over its entire thickness along the growth direction.

[0017] In some embodiments, the first region further comprises an n-doped portion of the first semiconductor layer adjacent to the first section of the active layer in the growth direction, and the second region further comprises a p-doped portion of the second semiconductor layer adjacent to the second section of the active layer in the growth direction. The n-doped portion of the first semiconductor layer may, for example, be n-doped over its entire thickness along the growth direction, and the p-doped portion of the second semiconductor layer may, for example, be p-doped over its entire thickness along the growth direction.

[0018] In some embodiments, the third region further comprises a substantially undoped portion of the first and / or second semiconductor layer, which borders the third portion of the active layer in the growth direction. In particular, portions of the first and / or second semiconductor layer above or below the third portion of the active layer may also be undoped.

[0019] In some embodiments, the optoelectronic device is configured to emit light when an electric current is applied to the first and second contact surfaces. In particular, the optoelectronic device is configured to emit light of a desired wavelength or spectrum when an electric current is applied to the first and second contact surfaces. The optoelectronic device, and especially its layers, may therefore comprise or consist of a material / material system configured to emit light when a current flows through it.

[0020] In some embodiments, the optoelectronic device further comprises a support layer, wherein the first semiconductor layer is arranged on the support layer. The support layer can, for example, be a semiconductor support layer, such as one from the group of III-V or II-VI semiconductor compounds. The support layer can be, for example, made of gallium arsenide (GaAs) or gallium phosphite (GaP).

[0021] In some embodiments, the first and / or second semiconductor layer is a diffusion layer or can at least act as such. In the case of a diffusion layer, the first and / or second semiconductor layer can be very thin and configured to promote the diffusion of p- and n-doping into the active layer.

[0022] In some embodiments, the first semiconductor layer is a confinement layer. The function of the confinement layer can be, for example, to provide a larger band gap than the active layer in order to suppress vertical transport of charge carriers toward a support layer located below the first semiconductor layer. Another function of the confinement layer can be, for example, to prevent diffusion of the p- and / or n-type dopant into a support layer located below the first semiconductor layer during a diffusion process.

[0023] One aspect describes a method for manufacturing an optoelectronic device, in particular a miniaturized light-emitting device. The method comprises the following steps: Providing a first semiconductor layer, a second semiconductor layer, and an active layer arranged between the first and second semiconductor layers along a growth direction; and Diffusion of an n-doping agent and a p-doping agent into the active layer such that a first section of the active layer is n-doped and forms a first region, a second section of the active layer is p-doped and forms a second region, and a third section of the active layer separates the first and second regions in a lateral direction that is substantially perpendicular to the growth direction, and is substantially undoped and forms a third region.

[0024] In some embodiments, the diffusion step of the n-type and p-type dopants into the active layer includes the provision, in particular the deposition, of the n-type and p-type dopants on the second semiconductor layer. In another embodiment, however, the diffusion step of the n-type and p-type dopants into the active layer includes the provision, in particular the deposition, of the n-type dopant on the first semiconductor layer or on a support layer below the first semiconductor layer, and the p-type dopant on the second semiconductor layer.

[0025] In some embodiments, the step of providing the n-doper and / or the p-doper includes at least one photolithographic step for masking areas of the first and / or second semiconductor layer that are to remain free of the n-doper and the p-doper when viewed in the growth direction.

[0026] In some embodiments, the diffusion of the n-type and p-type dopants into the active layer comprises two separate diffusion steps at different temperatures. However, the diffusion of the n-type and p-type dopants into the active layer can also consist of only one diffusion step at a desired temperature.

[0027] In some embodiments, both the n-doping agent and the p-doping agent can be deposited on the respective semiconductor layer, followed by a common diffusion step, while in another embodiment, one of the n-doping agents or the p-doping agent can be deposited on the respective semiconductor layer, followed by a first diffusion step, and then the other doping agent can be deposited on the respective semiconductor layer, followed by a separate second diffusion step. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Further aspects and embodiments in accordance with the proposed principle will become clear with regard to the various embodiments and examples that are described in detail in connection with the accompanying drawings, in which Fig. Figures 1A to 1C each show a side view of an embodiment of an optoelectronic device in accordance with some aspects of the proposed principle; Fig. Figure 2 shows a top view of an optoelectronic device that fulfills some aspects of the proposed principle; Fig. 3A and Fig. Figure 3B each shows a side view of an embodiment of an optoelectronic device in accordance with some aspects of the proposed principle; Fig. 4A and Fig. Figure 4B shows steps of a method for manufacturing an optoelectronic device in accordance with some aspects of the proposed principle; Fig. 5A and Fig. Figure 5B shows steps of a further method for manufacturing an optoelectronic device in accordance with some aspects of the proposed principle; and Fig. Figures 6A to 6C show steps of a further method for manufacturing an optoelectronic device in accordance with some aspects of the proposed principle. DETAILED DESCRIPTION

[0029] The following embodiments and examples illustrate various aspects and their combinations according to the proposed principle. The embodiments and examples are not always to scale. Likewise, various elements may be enlarged or reduced to highlight specific aspects. It is understood that the individual aspects of the embodiments and examples shown in the figures can readily be combined without contradicting the principle of the invention. Some aspects exhibit a regular structure or shape. It should be noted that minor differences and deviations from the ideal form may occur in practice without contradicting the inventive concept.

[0030] Furthermore, the individual figures and aspects are not necessarily depicted in the correct size, and the proportions between the individual elements may not be accurate. Some aspects are emphasized through an enlarged representation. However, terms such as "above," "above," "below," "under," "larger," "smaller," and the like are correctly represented in relation to the elements within the figures. It is therefore possible to deduce such relationships between the elements based on the figures.

[0031] Fig. Figure 1A shows a side view of an optoelectronic device 1, in particular a miniaturized light-emitting device, according to some aspects of the proposed principle. The optoelectronic device 1 has a semiconductor layer stack consisting of a first semiconductor layer 2, a second semiconductor layer 3, and an active layer 4 arranged between the first and second semiconductor layers. The first and second semiconductor layers 2, 3, and the active layer 4 extend in a lateral direction L that is substantially perpendicular to a growth / stacking direction G of the layer stack.

[0032] A first section 4a of the active layer 4, together with a first section 2a, 3a of the first and second semiconductor layers 2, 3, is n-doped and forms a first region 6. A second section 4b of the active layer 4, together with a second section 2b, 3b of the first and second semiconductor layers 2, 3, is p-doped and forms a second region 7. A third region 8, which is essentially undoped, is arranged between the first and second regions 6, 7. The third region is formed by a third section 4c of the active layer 4, together with a third section 2c, 3c of the first and second semiconductor layers 2, 3, and separates the first and second regions 6, 7 in the lateral direction L.

[0033] The semiconductor layer stack is further arranged on a support layer 10, with the first layer 2 facing the support layer 10. The support layer can also consist of a semiconductor material and serve as the basis for the growth of the semiconductor layer stack.

[0034] In the illustrated embodiment, the first semiconductor layer 2 is configured as a confinement layer. The function of the confinement layer can be, for example, to provide a larger band gap than the active layer 4 in order to suppress vertical transport of charge carriers towards the support layer 10 located below the first semiconductor layer 2. Another function of the confinement layer can be, for example, to prevent diffusion of the p- and / or n-doping material into the support layer 10 during a diffusion process. The second semiconductor layer 3, on the other hand, is configured as a diffusion layer or at least acts as a diffusion layer and is designed to promote diffusion of the p- and n-doping material into the active layer 4.

[0035] The optoelectronic device 1 further comprises a first and a second contact surface 5a, 5b for supplying the optoelectronic device 1 with an electric current. The first contact surface 5a is electrically coupled to the first region 6 and, in particular, to the first section 4a of the active layer 4, and the second contact surface 5b is electrically coupled to the second region 7 and, in particular, to the second section 4b of the active layer 4. The optoelectronic device is configured, in particular, to emit light when an electric current is applied to the first and the second contact surfaces 5a, 5b. Due to the laterally separated p-doped and n-doped sections of the active layer, a pn junction is formed along the lateral direction L, in which electrons e and electron holes h diffuse laterally towards each other and recombine, generating light hv.

[0036] Transparent contacts, e.g., indium tin oxide (ITO) contacts, can be grown on the contact surfaces 5a, 5b, particularly if the support layer 10 is to remain below the semiconductor layer stack and light emission in the growth direction G is desired. However, a thin-film approach with reflective contacts on the contact surfaces 5a, 5b can also be advantageous if light emission in the direction opposite to the growth direction G is desired. In the latter case, it can also be advantageous to omit the support layer 10, as is done in the embodiments shown in Fig. 1C, Fig. 3A and Fig. 3B is shown.

[0037] Fig. Figure 1B shows a side view of another embodiment of an optoelectronic device 1. In contrast to the one in Fig. In the embodiment shown in Figure 1A, the first semiconductor layer is essentially undoped over its entire volume. The n-doped first region 6 thus comprises the first section 4a of the active layer 4 together with a first section 3a of the second semiconductor layer 2, but essentially no part of the first semiconductor layer 2. The p-doped second region 7, on the other hand, comprises the second section 4b of the active layer 4 together with a second section 3b of the second semiconductor layer 2, but essentially no part of the first semiconductor layer 2.

[0038] The degree of n- and p-doping of the first semiconductor layer 2 can depend in particular on the extent to which the n- and p-doping material diffuses through the second semiconductor layer 3 and the active layer 4 to or into the first semiconductor layer 2 during the manufacture of the optoelectronic device 1.

[0039] As in Fig. As shown in Figure 1B, the contact areas 5a', 5b' can also be arranged on opposite side surfaces 9c and 9d of the optoelectronic device 1 to enable vertical contacting of the optoelectronic device 1. The optoelectronic device 1 can therefore, for example, be rotated by 90° and placed with either the contact area 5a' or the contact area 5b' onto a contact pad, for example, of a backplane, while an upper contact can be provided on the contact area opposite the backplane.

[0040] Fig. Figure 1C shows a side view of another embodiment of an optoelectronic device 1, which omits the support layer 10 and has a substantially undoped first semiconductor layer 2. The embodiments shown here are to be understood as exemplary embodiments, and features or modifications between the embodiments shown can be applied to any other embodiment of the proposed principle.

[0041] Fig. Figure 2 shows a top view of an optoelectronic device 1 according to some aspects of the proposed principle. In particular, it shows Fig. 2. The advantage of the invention is to reduce potential areas for non-radiative recombination along the boundary regions of the active layer 4 of the optoelectronic device 1. Due to the n- and p-doping of the active layer 4 and thus the lateral separation of the n- and p-doped regions within the active layer 4, electrons 3 and holes h are only present together in the undoped center of the active layer 4. Therefore, non-radiative recombination centers within the active layer 4 along the side faces 9a, 9b, 9c, and 9d are no longer critical, with the exception of the sections of the active layer 4 along the two side faces 9a and 9b (represented by the “X”), since no electrons 3 and holes h are present for non-radiative recombination.In contrast, with a conventional vertical separation of the n- and p-doped regions in an LED, and thus an essentially undoped active layer, non-radiative recombination centers within the active layer along its entire perimeter are critical. Therefore, compared to conventional LEDs, the potential areas for non-radiative recombination along the edge regions of the active layer 4 of the optoelectronic device 1 are reduced from the entire perimeter of the active layer to the sections of the active layer 4 along the two face surfaces 9a and 9b (represented by the "X"s). This results from the fact that the face surfaces 9a, 9b, 9c, and 9d, with the exception of the portions of the active layer 4 along the two face surfaces 9a and 9b (represented by the "X"s), are "shielded" by the p- and n-doped regions.This greatly reduces the diffusion of electrons e and electron holes h into the interference sites for non-radiative recombination on the side surfaces 9a, 9b, 9c and 9d, thereby significantly reducing non-radiative recombination and thus increasing the efficiency of the optoelectronic device 1.

[0042] To increase the area / volume of the undoped part of the active layer 4, the optoelectronic device 1 can be designed as an elongated rectangle instead of a square, as shown in Fig. Figure 2 shows that the extent of the optoelectronic device 1, and in particular the active layer 4, in the lateral direction L can be smaller than the extent of the optoelectronic device 1, and in particular the active layer 4, in the direction perpendicular to the lateral direction L (along the side faces 9c and 9d). Another way to increase the area / volume of the undoped part of the active layer 4 is to increase the thickness of the active layer along the growth direction G, for example by increasing the number of quantum wells. In this way, the efficiency of the optoelectronic device 1 can be further increased.

[0043] Fig. 3A and Fig. Figure 3B shows a side view of another embodiment of an optoelectronic device 1. In contrast to the ones shown in the Fig. In embodiments 1A to 1C, the first and second regions 6 and 7 are arranged “diagonally” within the optoelectronic device 1.

[0044] In particular, as in Fig. Figure 3A shows a first contact region 5a adjacent to the first region 6 on the first semiconductor layer 2, and a second contact region 5b adjacent to the second region 7 on the second semiconductor layer 3. A first section 4a of the active layer 4 is n-doped together with a first section 2a, 3a of the first and second semiconductor layers 2, 3, forming a first region 6, wherein the first section 2a of the first semiconductor layer 2 extends over the entire thickness of the first semiconductor layer 2, and the first section 3a of the second semiconductor layer 3 extends only through a portion of the second semiconductor layer 3.Furthermore, a second section 4b of the active layer 4 together with a second section 2b, 3b of the first and second semiconductor layers 2, 3 is p-doped and forms a second region 7, wherein the second section 3b of the second semiconductor layer 3 extends over the entire thickness of the second semiconductor layer 3 and the second section 2b of the first semiconductor layer 2 extends only through a section of the first semiconductor layer 2.

[0045] The degree to which the first / second semiconductor layer is n- and p-doped can depend in particular on the extent to which the n- and p-doping material diffuses through the first / second semiconductor layer and the active layer 4 to or into the first / second semiconductor layer during the manufacture of the optoelectronic device 1.

[0046] Fig. Figure 3B shows a side view of another embodiment of an optoelectronic device 1. In contrast to the one in Fig. In the embodiment shown in 3A, the second semiconductor layer 3 is essentially undoped in a region adjacent to the first region 6, and the first semiconductor layer 2 is essentially undoped in a region adjacent to the second region 7. The contact regions 5a', 5b' are arranged, by way of example, on opposite side faces 9c and 9d of the optoelectronic device 1 to enable vertical contacting of the optoelectronic device 1, but can also be arranged as in the embodiment of Fig. 3A are shown arranged.

[0047] In the Fig. 3A and Fig. In the embodiments shown in 3B, the first semiconductor layer 2 can in particular also be designed as a diffusion layer or at least act as a diffusion layer and be designed in such a way that it promotes a diffusion of the n-doping material into the active layer 4 in the first region 6.

[0048] Fig. 4A and Fig. Figure 4B shows steps of a method for fabricating an optoelectronic device 1 in accordance with some aspects of the proposed principle. In a first step, a semiconductor layer stack consisting of a first semiconductor layer 2, a second semiconductor layer 3, and an active layer 4, arranged between the first and second semiconductor layers along a growth direction G, is provided on a substrate layer 10.

[0049] In a further step, as in Fig. As shown in Figure 4A, a first photomask 11a is provided, covering the second semiconductor layer 3 and having openings over the subsequently formed first region 6. Subsequently, an n-type dopant is diffused into the semiconductor layer stack and, in particular, at least into the active layer 4, so that a first section 4a of the active layer is n-doped and forms the first region 6. Through the diffusion process, a first section 3a of the second semiconductor layer 3 is also n-doped, as is a first section 2a of the first semiconductor layer 2. The degree of n-doping of the first semiconductor layer 2 depends on how far the n-type dopant diffuses through the second semiconductor layer 3 and the active layer 4 into the first semiconductor layer 2 and can be adjusted, for example, by the diffusion parameters (time, temperature, dopant, etc.) during the fabrication of the optoelectronic device 1.

[0050] Then, as in Fig. As shown in Figure 4B, a second photomask 11b is provided, covering the second semiconductor layer 3 and having openings over the subsequently formed second region 7. A p-type dopant is then diffused into the semiconductor layer stack, and in particular into the active layer 4, so that a second section 4b of the active layer is p-doped and forms the second region 7. Through the diffusion process, a second section 3b of the second semiconductor layer 3 is also p-doped, as is a second section 2b of the first semiconductor layer 2. The degree of p-doping of the first semiconductor layer 2, in turn, depends on how far the p-type dopant diffuses through the second semiconductor layer 3 and the active layer 4 to or into the first semiconductor layer 2 and can be adjusted, for example, by the diffusion parameters (time, temperature, dopant, etc.) during the fabrication of the optoelectronic device 1.

[0051] The first and second photomasks 11a and 11b, as well as the diffusion parameters, are chosen such that a third section 4c of the active layer, which separates the first and second regions 6, 7 in a lateral direction L, is essentially undoped. The diffusion steps of the n-type and p-type dopants into the active layer 4 feature, in particular, two separate diffusion steps at different temperatures to prevent further diffusion of the n-type dopant towards the first semiconductor layer 2 during the second diffusion step. Which dopant diffuses in first is, in principle, irrelevant; only the diffusion temperatures should differ significantly, and the dopant with the considerably higher diffusion temperature should diffuse in first.

[0052] Fig. 5A and Fig. Figure 5B shows steps of a further method for manufacturing an optoelectronic device 1 according to some aspects of the proposed principle. In contrast to the one in Fig. 4A and Fig. In the embodiment shown in Figure 4B, the diffusion of the two dopants is carried out in a single step. For this purpose, a first dopant 12a is deposited onto the second semiconductor layer 3 using a first photomask 11a (see Figure 4B). Fig. 5A) and in a further step a second dopant 12b is deposited on the second semiconductor layer 3 using a second photomask 11b (see Fig. 5B). The diffusion of the two dopants then takes place in a single step, resulting in the optoelectronic device 1.

[0053] Fig. Figures 6A to 6D show steps of a further method for fabricating an optoelectronic device 1 according to some aspects of the proposed principle. A first dopant 12a is applied to a substrate layer 10 using a first photomask 11a (see Figure 6A to 6D). Fig. 6A). Then, on the support layer 10 and the first dopant 12a, a semiconductor layer stack is provided, consisting of a first semiconductor layer 2, a second semiconductor layer 3, and an active layer 4, which is arranged between the first and the second semiconductor layer along a growth direction G (see Fig. 6B). In a further step, a second dopant 12b is deposited on the second semiconductor layer 3 using a second photomask 11b (see Fig. 6C). The diffusion of the two dopants then occurs in a single step, resulting in the in Fig. The optoelectronic device 1 shown in Figure 6D is created. LIST OF REFERENCES 1 optoelectronic device 2 Semiconductor layer Section 2a, 2b, 2c 3 Semiconductor layer Sections 3a, 3b, and 3c 4 active layer Sections 4a, 4b, and 4c 5a, 5b, 5a', 5b' Contact area 6 first region 7 second region 8 third region 9a, 9b, 9c, 9d Side surface 10 carrier layer 11a, 11b Photo mask 12a n-doping agent 12b p-doper G Growth direction L lateral direction h holes e electrons hv light

Claims

An optoelectronic device (1), in particular a miniaturized light-emitting device, comprising: a first semiconductor layer (2); a second semiconductor layer (3); an active layer (4) arranged between the first and the second semiconductor layer; and a first and a second contact surface (5a, 5b, 5a', 5b'); wherein the first and second semiconductor layers (2, 3) and the active layer (4) extend in a lateral direction (L) that is substantially perpendicular to a growth direction (G) of the first and second semiconductor layers (2, 3) and the active layer (4); wherein a first section (4a) of the active layer (4) is n-doped and forms a first region (6); wherein a second section (4b) of the active layer (4) is p-doped and forms a second region (7);wherein a third section (4c) of the active layer (4) separates the first and second regions (6, 7) in the lateral direction (L) and is essentially undoped and forms a third region (8); and wherein the first contact surface (5a, 5a') is electrically coupled to the first region (6) and the second contact surface (5b, 5b') is electrically coupled to the second region (7). Optoelectronic device according to claim 1, wherein the active layer (4) has a multi-quantum well structure. Optoelectronic device according to claim 2, wherein the active layer (4) has a quantum wave mixed band gap in the first and second regions (6, 7). Optoelectronic device according to one of claims 1 to 3, wherein only two side surfaces (9a, 9b) of the optoelectronic device (1) each have a part of the third area (8). Optoelectronic device according to one of claims 1 to 4, wherein the active layer (4) in the first section (4a) is n-doped over its entire thickness along the growth direction (G) and / or the active layer (4) in the second section (4b) is p-doped over its entire thickness along the growth direction (G). Optoelectronic device according to any one of claims 1 to 5, wherein the optoelectronic device (1) is configured to emit light when an electric current is applied to the first and second contact areas (5a, 5b, 5a', 5b'). Optoelectronic device according to one of claims 1 to 6, wherein the first region (6) further comprises an n-doped section (2a, 3a) of the first and / or second semiconductor layer (2, 3) which is adjacent to the first section (4a) of the active layer (4) in the growth direction (G). Optoelectronic device according to one of claims 1 to 7, wherein the second region (7) further comprises a p-doped section (2b, 3b) of the first and / or second semiconductor layer (2, 3) which is adjacent to the second section (4b) of the active layer (4) in the growth direction (G). Optoelectronic device according to one of claims 1 to 8, wherein the third region (8) further comprises a substantially undoped section (2c, 3c) of the first and / or second semiconductor layer (2, 3) which adjoins the third section (4c) of the active layer (4) in the growth direction (G). Optoelectronic device according to one of claims 1 to 9, further comprising a carrier layer (10), wherein the first semiconductor layer (2) is arranged on the carrier layer (10). Optoelectronic device according to any one of claims 1 to 10, wherein the first and / or second semiconductor layer (2, 3) is a diffusion layer. Optoelectronic device according to one of claims 1 to 11, wherein the first semiconductor layer (2) is a boundary layer. Method for fabricating an optoelectronic device (1) comprising the steps of: providing a first semiconductor layer (2), a second semiconductor layer (3) and an active layer (4) arranged between the first and second semiconductor layers along a growth direction (G); and diffusing an n-doper and a p-doper into the active layer (4) such that a first section (4a) of the active layer (4) is n-doped and forms a first region (6), a second section (4b) of the active layer (4) is p-doped and forms a second region (7), and a third section (4c) of the active layer (4) separates the first and second regions (6, 7) in a lateral direction (L) that is substantially perpendicular to the growth direction (G), and is substantially undoped and forms a third region (8). Method according to claim 13, wherein the step of diffusing the n-doper and the p-doper into the active layer (4) comprises providing the n-doper (12a) and the p-doper (12b) on the second semiconductor layer (3). Method according to claim 13, wherein the step of diffusing the n-doper (12a) and the p-doper (12b) into the active layer (4) comprises providing the n-doper (12a) on the first semiconductor layer (2) or on a support layer (10) below the first semiconductor layer (2) and the p-doper (12b) on the second semiconductor layer (3). Method according to claim 14 or 15, wherein the step of providing the n-doper and the p-doper on the first and / or second semiconductor layer (2, 3) includes at least one photolithographic step for masking areas which, viewed in the growth direction (G), are to remain free of the n-doper and the p-doper. Method according to one of claims 13 to 16, wherein the step of diffusing the n-doping agent and the p-doping agent into the active layer (4) comprises two separate diffusion steps at different temperatures.

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