EP2011161A2

EP2011161A2 - Optoelectronic semiconductor component

Info

Publication number: EP2011161A2
Application number: EP07722298A
Authority: EP
Inventors: Christoph Eichler; Stephan Miller; Uwe Strauss; Volker HÄRLE; Matthias Sabathil
Original assignee: Osram Opto Semiconductors GmbH
Current assignee: Ams Osram International GmbH
Priority date: 2006-04-25
Filing date: 2007-04-25
Publication date: 2009-01-07
Also published as: US8093607B2; JP5623074B2; CN101443923A; US20090309113A1; CN101443923B; DE102006061167A1; TWI354381B; TW200746479A; WO2007121739A2; KR20080112410A; JP2009534859A; KR101370257B1; WO2007121739A3

Abstract

Disclosed is an optoelectronic semiconductor component comprising a supporting substrate as well as an intermediate layer that provides adhesion between the supporting substrate and a component structure. The component structure encompasses an active layer that is used for generating radiation.

Description

Optoelectronic semiconductor component

An optoelectronic semiconductor component is specified.

The document DE 19640594 and the document US 2005/0247950 describe optoelectronic semiconductor components as well as methods for their production.

An object to be solved is to specify an optoelectronic semiconductor component which has a particularly long service life. Another object to be achieved is to specify an optoelectronic semiconductor component which has a particularly high efficiency. Another object is to provide a method for producing such an optoelectronic semiconductor component.

The optoelectronic semiconductor component described here is, for example, a light-emitting diode, that is to say a light-emitting diode or a laser diode. In particular, the optoelectronic semiconductor component may also be an RCLED (resonant cavity light emitting diode) or a VCSEL (vertical cavity surface emitting laser).

In accordance with at least one embodiment of the optoelectronic semiconductor component, the optoelectronic component has a carrier substrate. The functional layers of the optoelectronic semiconductor component - that is to say a component structure of the optoelectronic semiconductor component which is one for generating radiation provided active layer - are mechanically fixedly connected to the carrier substrate. Furthermore, it is possible for the component structure of the optoelectronic component to be electrically contactable via the carrier substrate. In this case, the carrier substrate is preferably not a growth substrate on which the component structure of the optoelectronic

Semiconductor device is epitaxially deposited, but to a substrate on which the device structure is applied after its preparation or to which a wear layer is applied, is deposited on the epitaxial deposition of the device structure after application.

In accordance with at least one embodiment of the optoelectronic semiconductor component, the optoelectronic semiconductor component comprises an intermediate layer which mediates adhesion between the carrier substrate and the component structure of the optoelectronic semiconductor component. The intermediate layer can be, for example, a bonding layer, by means of which the carrier substrate is bonded to the component structure. Furthermore, it is possible for the intermediate layer to mechanically bond the carrier substrate to a wear layer. On the side facing away from the carrier substrate side of the wear layer, the device structure may then be grown epitaxially.

In accordance with at least one embodiment of the optoelectronic semiconductor component, the optoelectronic semiconductor component comprises a component structure with an active layer, which is provided for generating radiation. Preferably, the active layer is suitable for generating electromagnetic radiation in the blue and / or ultraviolet spectral range. The active layer may include multiple semiconductor layers. By way of example, the active layer comprises a pn junction, a heterostructure, a single quantum well structure and / or a multiple quantum well structure. In particular, the term quantum well structure also encompasses any structure in which charge carriers can undergo quantization of their energy states by confinement. In particular, the term quantum well structure does not include an indication of the dimensionality of the quantization. It thus includes quantum wells, quantum wires and quantum dots and any combination of these structures.

In accordance with at least one embodiment of the optoelectronic semiconductor component, the optoelectronic semiconductor component comprises a carrier substrate, an intermediate layer which mediates adhesion between the carrier substrate and a component structure, wherein the component structure comprises an active layer which is provided for generating radiation.

In accordance with at least one embodiment of the optoelectronic semiconductor component, the component structure has a wear layer. The wear layer is connected to the carrier substrate by means of the intermediate layer. On the side facing away from the carrier substrate side of the wear layer, the device structure is epitaxially grown. That is, the device structure with the active layer follows the wear layer in the growth direction. The wear layer preferably consists of GaN with a particularly low dislocation density. Preferably, the dislocation density is less than 10 ⁸ per cm ² , more preferably less than 10 ⁷ per cm ² . That is, the wear layer is for example, a layer of high-quality, low-defect semiconductor material such as GaN. By contrast, the carrier substrate may be formed from a less expensive material, for example defect-rich GaN.

In accordance with at least one embodiment of the optoelectronic semiconductor component, the useful layer has a separating surface which faces away from the carrier substrate. The wear layer is triggered, for example, from a thicker Nutzsubstrat along the separation surface. The separation surface is preferably planarized and epitaxially overgrown. For example, the device structure is epitaxially deposited on this planarized interface.

In accordance with at least one embodiment of the optoelectronic semiconductor component, the intermediate layer is electrically insulating. For this purpose, the intermediate layer can consist of a silicon nitride or a silicon oxide or contain at least one of these materials. For example, the intermediate layer contains at least one of the following materials: SiN, SiO 2 _/ Si 3 N 4, Al 2 O 3, Ta 2 O, HfO 2.

In accordance with at least one embodiment of the optoelectronic semiconductor component, the intermediate layer comprises at least one oxide, nitride and / or fluoride of at least one of the following elements: Si, Mg, Al, Hf, Nb, Zr, Sc, Ta, Ga, Zn, Y, B Ti.

In accordance with at least one embodiment of the optoelectronic semiconductor component, the intermediate layer consists of an oxygen-containing compound. In accordance with at least one embodiment of the optoelectronic semiconductor component, the intermediate layer has a refractive index which is smaller than the refractive index of the material from which the wear layer is formed. The intermediate layer may then form a mirror for the electromagnetic radiation generated in the active layer.

In accordance with at least one embodiment of the optoelectronic semiconductor component, the reflectivity of the intermediate layer is increased by a layer sequence of high and low-refraction layers for small angles of incidence. That is, the intermediate layer comprises a layer sequence of alternating high and low refractive layers, which may form, for example, a Bragg mirror structure.

In accordance with at least one embodiment of the optoelectronic semiconductor component, the intermediate layer is formed particularly smoothly on the side which faces the component structure. Such a smooth intermediate layer allows a particularly good reflectivity of the intermediate layer.

In accordance with at least one embodiment of the optoelectronic semiconductor component, the side of the intermediate layer which faces the carrier substrate is made rough. This allows a good transmission of electromagnetic radiation in the direction of the radiation exit surface of the semiconductor device. This is because such a rough interface of the intermediate layer reduces the probability of total reflection at the intermediate layer.

In accordance with at least one embodiment of the optoelectronic semiconductor component, the intermediate layer mediates a electrical contact between the carrier substrate and the device structure. The intermediate layer then contains or consists, for example, of a transparent conductive oxide (TCO), for example ITO (indium tin oxide) or ZnO.

In accordance with at least one embodiment of the optoelectronic semiconductor component, the intermediate layer is at least partially permeable to the electromagnetic radiation generated in the active layer. For example, the refractive index of the intermediate layer is adapted to the refractive index of the material from which the wear layer is formed, and / or the material from which the carrier substrate is formed. That is, the refractive index of the intermediate layer is then approximately equal to the refractive index of the material from which the wear layer is formed, and / or approximately equal to the refractive index of the material from which the carrier substrate is formed. In approximately the same way means that the refractive index of the intermediate layer differs by a maximum of 20% from the refractive index of the material, preferably at most 10%, more preferably at most 5% of the refractive index of the material of the wear layer and / or the carrier substrate.

In accordance with at least one embodiment of the optoelectronic semiconductor component, a radiation exit surface of the optoelectronic semiconductor component is roughened. Such a roughening can take place, for example, by means of in-situ roughening during the epitaxy through V-shaped openings, which preferably occur at dislocations. Another possible technique for roughening the radiation exit surface is the formation of mesets on the radiation exit surface. That means on the Radiation exit surface mesa structures are produced by epitaxial growth or etching.

In accordance with at least one embodiment, a highly transparent contact layer is applied to at least one side of the optoelectronic semiconductor component. The highly transparent contact layer may for example contain or consist of a transparent conductive oxide.

In accordance with at least one embodiment, the semiconductor component is designed in the manner of a flip-chip. In this case, the component structure is preferably provided with a reflective electrode. The the

Component side facing away from the carrier substrate is then preferably, as described above, roughened and structured to improve the light extraction by the substrate. That is, the radiation exit surface of the optoelectronic semiconductor component is formed at least in places by the side of the carrier substrate which faces away from the component structure.

In accordance with at least one embodiment, the side of the carrier substrate facing away from the component structure is mirrored so that the electromagnetic radiation generated in the active layer is reflected. In this case, at least a part of the radiation exit surface is given by the side of the component structure which faces away from the carrier substrate.

In accordance with at least one embodiment of the optoelectronic semiconductor component, the intermediate layer comprises a dielectric mirror or forms such a dielectric mirror.

In accordance with at least one embodiment of the optoelectronic semiconductor component, the intermediate layer comprises a Bragg mirror or forms such a Bragg mirror.

According to at least one embodiment of the optoelectronic semiconductor component, the intermediate layer contains at least one of the following materials: SiN, SiO ₂ , Si 3 N 4, Al ₂ O 3, Ta ₂ O ₅ , HfO ₂ .

In accordance with at least one embodiment of the optoelectronic semiconductor component, the intermediate layer comprises a Bragg mirror or forms a Bragg mirror which contains a multiplicity of alternating first and second layers. In this case, the first layers are preferably formed from SiO ₂ and / or Al ₂ O 3, and the second layers are preferably formed from Ta ₂ Os and / or HfO ₂ .

In accordance with at least one embodiment, the intermediate layer formed as a dielectric mirror or Bragg mirror is a bonding layer, which mediates adhesion between the carrier substrate and the component structure of the optoelectronic semiconductor component. That is to say, the intermediate layer performs a dual function in this embodiment: it serves to reflect the electromagnetic radiation generated in operation in the active layer of the optoelectronic semiconductor component and provides a mechanical adhesion between the carrier substrate and the component structure. In accordance with at least one embodiment of the optoelectronic semiconductor component, the optoelectronic component comprises an output mirror, which is arranged on the side of the component structure facing away from the intermediate layer. By way of example, the coupling-out mirror is formed by at least one of the following mirrors: metallic mirror, dielectric mirror, Bragg mirror.

In accordance with at least one embodiment of the optoelectronic semiconductor component, the coupling-out mirror comprises a Bragg mirror which contains a multiplicity of alternating first and second layers. In this case, the first layers are preferably formed from SiO 2 and / or Al 2 O 3 and the second layers are preferably formed from Ta 2θs and / or HfO 2.

In this case, it is possible, in particular, for the intermediate layer formed as a mirror and the coupling-out mirror to form a resonator for the electromagnetic radiation generated in the active layer of the component structure of the optoelectronic semiconductor component in accordance with at least one embodiment of the optoelectronic semiconductor component. This embodiment is particularly well suited for an RCLED or a VCSEL.

In accordance with at least one embodiment of the optoelectronic semiconductor component, the distance between the intermediate layer and the outcoupling mirror is at most 10 μm, preferably at most 3 μm, particularly preferably at most 2 μm.

In accordance with at least one embodiment of the optoelectronic semiconductor component, a contact layer, which is a contact layer, is arranged between the component structure and the outcoupling mirror transparent conductive oxide comprises or consists of such. For example, the contact layer contains or consists of ITO. That is, between the side of the component structure facing away from the intermediate layer and the outcoupling mirror, a contact layer is arranged which contains or consists of a transparent conductive oxide. The component structure and the coupling-out mirror preferably each directly adjoin this contact layer.

In accordance with at least one embodiment of the optoelectronic semiconductor component, the thickness of the contact layer which is arranged between the component structure and the outcoupling mirror satisfies the following relationship: d = (mλ / 2) / n.sub.s • where d is the thickness of the contact layer, λ is the wavelength of in the active layer generated electromagnetic radiation, ¹ ^ -KS ^ ie refractive index of the material of the contact layer and m is a natural number ≥ 1.

Furthermore, a method for producing an optoelectronic semiconductor component is specified.

In accordance with at least one embodiment of the method, the method comprises growing an active layer on a wear layer. The wear layer is, for example, a layer of GaN which has a particularly small dislocation density.

In accordance with at least one embodiment of the method for producing an optoelectronic semiconductor component, the method comprises providing a carrier substrate. The carrier substrate may be for Example, to a low-cost GaN substrate act, which has a relatively high dislocation density.

In accordance with at least one embodiment of the method, the method comprises connecting the carrier substrate to a useful substrate by means of an intermediate layer. For example, the payload substrate is a thick, low dislocation GaN substrate.

In accordance with at least one embodiment of the method, the method comprises producing a break seed layer in the payload substrate. By way of example, this fracture seed layer can take place by means of the implantation of hydrogen ions into the payload substrate. As a result, a fracture seed layer is formed, along which a part of the useful substrate can be detached in a subsequent method step, so that a useful layer remains, which is connected to the carrier substrate via the intermediate layer. For example, the wear layer can be removed by annealing from the remaining useful substrate. Such a method for producing a quasi-substrate having a wear layer is described, for example, in the document WO 2005/004231, the disclosure content of which is hereby expressly incorporated by reference.

In accordance with at least one embodiment of the method for producing an optoelectronic semiconductor component, the method comprises the following steps:

Providing a carrier substrate,

Connecting the carrier substrate to a user substrate by means of an intermediate layer,

Producing a break seed layer in the payload substrate, Detaching a part of the Nutzsubstrats so that a Nutzschicht remains, which is connected to the carrier substrate, and

- Growing a device structure comprising an active layer, on the wear layer.

In the following, the optoelectronic semiconductor component described here as well as the method for producing the optoelectronic semiconductor component will be explained in more detail by means of exemplary embodiments and the associated figures. In the exemplary embodiments and figures, identical or identically acting components are each provided with the same reference numerals. The illustrated elements are not to be considered as true to scale, but individual elements may be exaggerated to better understand.

FIG. 1 shows a schematic sectional view of a first exemplary embodiment of an optoelectronic semiconductor component described here.

FIG. 2 shows a schematic sectional illustration of a second exemplary embodiment of an optoelectronic semiconductor component described here.

FIG. 3 shows a schematic sectional illustration of a third exemplary embodiment of an optoelectronic semiconductor component described here. FIG. 4 shows a schematic sectional representation of a fourth exemplary embodiment of an optoelectronic semiconductor component described here.

FIG. 5 shows a schematic sectional illustration of a fifth exemplary embodiment of an optoelectronic semiconductor component described here.

FIG. 6 shows a schematic plot of the reflectivity at the intermediate layer.

FIG. 7 shows a schematic plot of the intensity of the radiation emitted by the component.

FIG. 1 shows a schematic sectional illustration of a first exemplary embodiment of an optoelectronic semiconductor component described here.

The optoelectronic semiconductor component comprises a carrier substrate 1. The carrier substrate 1 is formed from a low-cost GaN which has a relatively high dislocation density.

An intermediate layer 2, which has a lower refractive index and good adhesion to GaN, is applied to the carrier substrate .1. For example, the intermediate layer 2 is formed of SiO 2. The thickness of the intermediate layer 2 is preferably at least 100 ran.

On the intermediate layer 2, a device structure 50 is applied. The device structure 50 includes a Wear layer 3, which consists of GaN and is at least partially separated from a Nutzsubstrat. The dislocation density of the wear layer is less than 10 ^ per cm ² , preferably smaller

10 ⁷ per cm ² . The wear layer 3 has a release layer 4 which faces away from the support substrate 1. The wear layer 3 was separated along the release layer 4 from the Nutzsubstrat.

The wear layer 3 follows an electron injection layer 12 after. The electron injection layer 12 is, for example, a layer composed of n-AlInGaN. It is also possible for the wear layer 3 to form the electron injection layer 12. In this case, the wear layer 3 is separated from an n-AlInGaN Nutzsubstrat.

The electron injection layer 12 is followed by an active layer 5. The active layer 5 comprises at least one structure provided for the generation of radiation. By way of example, the active layer 5 may comprise a pn junction, a heterostructure, a quantum well structure and / or a multiple quantum well structure.

The active layer 5 is followed by a second conductive layer, for example a p-AHnGaN hole injection layer 6, which is preferably roughened and / or patterned on its side facing away from the active layer 5, in order to increase the probability of a radiation exit. For this purpose, it is also possible for the mesettes to be structured in the hole injection layer 6.

The hole injection layer 6 is followed by a contact layer 7, which for example contains or consists of a transparent conductive oxide, such as ITO. On the contact layer 7, a bonding pad 8 is applied, by means of which the device can be contacted electrically, for example by wire bonding.

In the exemplary embodiment described in conjunction with FIG. 1, the wear layer 3 or the electron injection layer 12 is exposed at least in places from the side facing away from the carrier substrate. A bond pad 9, which serves for n-side contacting of the optoelectronic semiconductor component, is applied to the wear layer 3 thus exposed. The optoelectronic semiconductor component described in connection with FIG. 1 is, for example, a light-emitting diode.

As an alternative to the embodiment described in connection with FIG. 1, the carrier substrate 1 may be electrically insulating and transparent. For example, the carrier substrate 1 is then made of sapphire. The intermediate layer 2 then preferably has a refractive index which is smaller than that of sapphire.

Alternatively, it is further possible that n- and p-type layers are reversed. That is, the carrier substrate may also adjoin a p-type layer.

Alternatively, it is further possible that the component is designed as a flip-chip component, in which a highly reflective mirror is applied to the hole injection layer 6 or the contact layer 7.

For many LEDs, for example, gallium nitride-based UV LEDs, the internal efficiency strongly depends on the defect density. This defect density is essentially determined by the substrate. Thus, defect areas are possible in the heteroepitaxy of gallium nitride on sapphire or of gallium nitride on silicon carbide 10 ⁸ to 10 ¹ O p _{ro cm} 2.

The second factor for the component efficiency is the coupling of the light beams generated in the semiconductor layer from the semiconductor into the environment. This decoupling is limited by reflections at the interface and by total reflection angle for the material transition.

Efficient light extraction is achieved with thin-film technology. The principle is to give the generated light beams several times a chance to extract light. For this purpose, the radiation exit surface is structured or roughened to obtain an angle change in the case of reflection, the opposite side is mirrored. Preferably, the structure between surface and mirror is kept as thin as possible in order to minimize absorption in the material. In thin-film chip technology, the laser lift-off process today dominates for substrate separation in conjunction with eutectic bonding. Alternatively, a wafer bonding process combined with grinding and etching away the mother substrate is possible. Light-emitting diode chips in thin-film construction are described, for example, in the publications WO 02/13281 A1 and EP 0 905 797 A2, the disclosure content of which with regard to the thin-film construction is hereby expressly incorporated by reference.

Another possibility for obtaining high light decoupling are epitaxial structures on a highly transparent substrate (for example sapphire) in conjunction with highly transparent ones Front-side current spreading layers (contacts) and in conjunction with changes in the paths of the reflected light, such as structuring or roughening surfaces and / or interfaces. On gallium nitride substrates, however, the efficiency of such structuring is greatly reduced, since gallium nitride is highly absorbent, especially for radiation in the UV range.

2 shows a second embodiment of an optoelectronic semiconductor device described here in a schematic sectional view.

In this exemplary embodiment, the intermediate layer 2 is designed to be electrically conductive and establishes a contact with the component structure 50. The intermediate layer 2 is or contains a transparent conductive oxide such as ITO or ZnO. The side of the carrier substrate 1 facing away from the component structure 50 is then preferably designed to be reflective for the electromagnetic radiation 20 generated in the active layer 5.

The active layer is preferably suitable for generating electromagnetic radiation 20 having a wavelength which is smaller than 380 nm. The wear layer 3 then consists or preferably contains AlGaN. Such a wear layer can be epitaxied on a GaN Nutzsubstrat. This layer relaxes during bonding to the carrier substrate after detachment from the Nutzsubstrat, so that for the epitaxial growth of the subsequent layers of the device structure 50 is a low-defect AlGaN wear layer 3 is available, which is integrated into the device structure 50. Such a wear layer 3 can then simultaneously form an electron injection layer 12. It is also possible that the wear layer 3 consists of AlGaInN or contains this material.

To produce the optoelectronic semiconductor component, as described, for example, in conjunction with FIGS. 1 or 2, a quasi-substrate 10 is first produced. For this purpose, for example, a high-quality GaN Nutzsubstrat is provided, preferably a

Defect density of less than 10 ^ per cm ^, more preferably of less than 10 ^ per cm ^. Optionally, an epitaxially grown layer or layer sequence, which may contain at least one of the following materials: GaN, AlGaN, InGaN, AlInGaN, is already present on the GaN Nutzsubstrat.

In the GaN payload substrate, a breaker seed layer is formed which extends in a lateral direction parallel to a major surface of the gallium nitride substrate. The break seed layer is preferably generated by the implantation of hydrogen ions from one side of the GaN payload substrate.

Subsequently, the GaN useful substrate is bonded to a carrier substrate 1 before or after generation of the break seed layer. Subsequently, the break seed layer is brought to form a lateral fracture. This can be done for example by tempering. The result is a wear layer 3, which is transferred from the Nutzsubstrat on the carrier substrate 1.

The wear layer 3 is connected to the carrier substrate 1 by means of an intermediate layer 2. FIG. 3 shows a third exemplary embodiment of an optoelectronic semiconductor component described here in a schematic sectional illustration.

The optoelectronic semiconductor component in turn comprises a carrier substrate 1, which is formed, for example, from low-cost GaN, which may have a relatively high dislocation density of greater than 10 ⁹ per cm ² . Alternatively, the carrier substrate 1 may also be formed of sapphire. An intermediate layer 2, which imparts adhesion between the carrier substrate 1 and a component structure 50, is applied to the carrier substrate 1. In the embodiment of Figure 3, the intermediate layer 2 is a Bragg mirror. The intermediate layer 2 then comprises a Bragg mirror or forms a Bragg mirror containing a plurality of alternating first and second layers. In this case, the first layers are preferably formed from SiO 2 and / or Al 2 O 3 and the second layers are preferably formed from Ta 2 O 5 and / or HfO 2.

The device structure 50 comprises a wear layer 3, which consists of high-quality GaN and is separated from a Nutzsubstrat. The dislocation density of the wear layer 3 is less than 10 ⁸ per cm ² , preferably less than 10 ⁷ per cm ² . Ideally, the interface between the wear layer 3 and the remaining device structure 50 is trouble-free. The wear layer 3 has a release layer 4 which faces away from the support substrate 1. The wear layer 3 is separated, for example by a detachment process along the release layer 4 from the Nutzsubstrat after bonding of the Nutzsubstrats on the carrier substrate 1 by means of the intermediate layer 2. The wear layer 3 follows a first conductive layer, which is, for example, an electron injection layer 12. The electron injection layer 12 contains or consists of n-AlInGaN in the exemplary embodiment of FIG.

The electron injection layer 12 is followed by an active layer 5, which comprises at least one structure provided for the generation of radiation.

The active layer 5 is followed by a second conductive layer, for example a hole injection layer 6. The hole injection layer 6 contains or consists of p-doped AlInGaN, for example.

The hole layer 6 is followed by a contact layer 7. The contact layer 7 is formed, for example, from ITO (indium tin oxide). The thickness of the contact layer 7 is preferably a multiple of half the wavelength of the electromagnetic radiation 20 generated in the active layer divided by the refractive index of the material of the contact layer 7. More preferably, the thickness of the contact layer 7 is the wavelength of the electromagnetic radiation generated in the active layer 5 Optionally, the contact layer 7 may be combined with a p + / n + tunnel junction.

On the side facing away from the active layer 5 of the contact layer 7, a metallic contact 8 is applied, which is for example annular. In the middle of the ring, a Auskoppelspiegel 13 is applied to the contact layer 7. The output mirror 13 forms a resonator with the mirror formed by the intermediate layer 2 the electromagnetic radiation 20 generated in the active layer 5. The output mirror 13 is embodied, for example, as a dielectric mirror, preferably as a Bragg mirror. The Auskoppelspiegel 13 may correspond in its structure, for example, the mirror of the intermediate layer 2. The outcoupling mirror 13 then comprises a Bragg mirror or forms a Bragg mirror containing a plurality of alternating first and second layers. In this case, the first layers are preferably formed from SiO 2 and / or Al 2 O 3 and the second layers are preferably formed from Ta 2 O 5 and / or HfO 2.

At least one metallic bonding pad 9, by means of which the optoelectronic semiconductor component can be electrically contacted on the n-side, is applied to a surface of the electron injection layer 12 which is exposed, for example, by means of a mesa etching.

The optoelectronic semiconductor component of FIG. 1 preferably forms an RCLED or a VCSEL.

The principle of RCLED or VCSEL is to embed a light-generating layer between two mirrors. The mirrors may be metal or dielectric layers.

Here, inter alia, a method for VCSEL and RCLED nitride-based is presented, which allows a resonant embedding of the active layer 5 between two mirrors 2, 13 with close proximity and at the same time includes a low-defect crystal structure.

Among other things, a new method is presented which uses a lattice-matched, low-offset epitaxy to produce an RCLED or VCSEL structure with a small number of low mirror gap modes. It can be optimally decoupled by the substrate light.

The substrate is prepared for a later detachment process, for example by means of hydrogen implantation. The substrate is optionally planarized and a Bragg mirror is applied to the substrate. For the Bragg mirror, for example, SiO 2 -TiO 2 layer sequences or SiO 2 -Ta 2 O 5 or SiO 2 -HfC> 2 or, instead of SiO 2, also Al 2 O 3 are suitable. Optionally, an SiO 2 release is not advantageous. The SiO 2 layer is bonded directly to a carrier substrate, for example sapphire or cost-effective - possibly defect-rich - GaN. A substrate wear layer 3 with the dielectric layers of the intermediate layer 2 is separated from the substrate by blisters and lateral cracking. The order of the steps can be varied.

It is lattice matched the LED or laser structure epitaxy on the transferred wear layer 3. The layer thickness is chosen so that the optical path - = thickness x refractive index - is a multiple of half the emission wavelength - lambda / 2 -. The preferred thickness is less than 10 microns, preferably less than 3 microns.

Subsequently, the chip structure is processed and the front side is mirrored. The mirror coating may be metallic, for example, of or silver or dielectric. In this case, a highly transparent contact layer by means of, for example, ITO in combination with an overlying dielectric mirror is preferred. The thickness of the contact layer is preferably a multiple of (Wavelength / 2) / refractive index, in particular Ix wavelength / refractive index.

The novel component consists of an AlGaInN layer package with a light-generating, active layer and a

Dislocation density less than 10 ^ per cm ^. The layer package lies at least partially between two mirrors, the layer thickness between the mirrors 2, 13 is less than 2 μm, preferably less than 10 × emission wavelength / (refractive index of the material between the mirrors 2, 13).

FIG. 4 shows a fourth exemplary embodiment of an optoelectronic semiconductor component described here in a schematic sectional illustration. In contrast to the exemplary embodiment described in connection with FIG. 3, in this embodiment the coupling-out mirror 13 is formed by a metal mirror which forms an ohmic contact with the contact layer 7. The output mirror 13 serves in addition to its optical properties for current injection into the opto-electronic semiconductor device.

FIG. 5 shows a fifth exemplary embodiment of an optoelectronic semiconductor component described here in a schematic sectional illustration. In contrast to the exemplary embodiment described in conjunction with FIG. 3, in this embodiment the metallic contact 8 is of annular design, such that it is located at the edge of the component. The uncovered by the metallic contact 8 surface of the active layer 5 facing away from the contact layer 7 is covered with a Auskoppelspiegel 13, which is formed for example by a Bragg mirror. FIG. 6 shows the reflectivity at the interface between a SiO 2 intermediate layer 2 and GaN as a function of the thickness d of the intermediate layer 2 for one wavelength, and the radiation of 460 nm generated by the active layer 5. The reflectivity here was for example for an optoelectronic Semiconductor device, as described in connection with Figure 1, determined.

The intermediate layer 2 proves to be particularly advantageous if the electromagnetic radiation generated in the active layer 5 is strongly absorbed in the carrier substrate 1. This is the case, in particular, for emission wavelengths of less than 380 nm for a GaN carrier substrate.

FIG. 7 shows the intensity ratio of the electromagnetic radiation generated by the active layer 5 for a defect density (DD) of 2 × 10 -4 per cm 2 in comparison to a defect density of 2 × 10 -4 per cm 2. Especially for wavelengths less than 420 nm, the reduced defect density due to the wear layer 3 has a particularly advantageous effect, for example in the case of a component as described in connection with FIG.

The invention is not limited by the description with reference to the embodiments. Rather, the invention encompasses any novel feature as well as any combination of features, including in particular any combination of features in the claims, even if this feature or combination itself is not explicitly stated in the claims or exemplary embodiments. This patent application claims the priorities of German patent applications 102006019109.9, 102006030252.4 and 102006061167.5 the disclosure of which is hereby incorporated by reference.

Claims

claims

1. Optoelectronic semiconductor device, comprising:

- A carrier substrate (1), and

- An intermediate layer (2), which provides adhesion between the carrier substrate (1) and a device structure (50), wherein the device structure (50) comprises an active layer (5), which is provided for generating radiation.

2. The optoelectronic semiconductor component according to at least one of the above claims, wherein the device structure (50) has a wear layer (3) which is arranged between the intermediate layer (2) and the active layer (5).

3. Optoelectronic semiconductor component according to at least one of the above claims, wherein the wear layer (3) has a separating surface (4), which faces away from the carrier substrate (1).

4. The optoelectronic semiconductor component according to at least one of the above claims, wherein the intermediate layer (2) is electrically insulating.

5. The optoelectronic semiconductor component according to claim 1, wherein the intermediate layer has a refractive index which is smaller than the refractive index of the material from which the wear layer is formed.

6. Optoelectronic semiconductor component according to at least one of the above claims, in which the intermediate layer (2) mediates an electrical contact between the carrier substrate (1) and the component structure (50).

7. An optoelectronic semiconductor component according to at least one of the above claims, wherein the intermediate layer (2) for the in the active layer (5) generated electromagnetic radiation is at least partially transmissive.

8. The optoelectronic semiconductor component according to the preceding claim, wherein the intermediate layer (2) contains a transparent conductive oxide.

9. An optoelectronic semiconductor component according to at least one of the preceding claims, wherein the refractive index of the intermediate layer (2) is approximately equal to the refractive index of the material from which the wear layer (3) is formed, and / or approximately equal to the refractive index of the material, from which the carrier substrate (1) is formed.

10. The optoelectronic semiconductor component according to at least one of the above claims, wherein the intermediate layer (2) comprises or is a dielectric mirror.

11. The optoelectronic semiconductor component according to at least one of the above claims, wherein the intermediate layer (2) comprises or is a Bragg mirror.

12. An optoelectronic semiconductor component according to at least one of the above claims, wherein the intermediate layer (2) consists of an oxygen-containing compound.

13. The optoelectronic semiconductor component according to at least one of the above claims, wherein the intermediate layer (2) contains at least one of the following materials: SiO 2, Al 2 O 3, Ta 2 O, HfO 2.

14. The optoelectronic semiconductor component according to claim 1, wherein the intermediate layer (2) contains at least one oxide, nitride and / or fluoride of at least one of the following elements: Si, Mg, Al, Hf, Nb, Zr, Sc, Ta, Ga, Zn, Y, B, Ti.

15. An optoelectronic semiconductor device according to at least one of the preceding claims, wherein the intermediate layer (2) comprises a Bragg mirror containing a plurality of alternating first and second layers, wherein the first layers of Siθ2 and / or AI2O3 are formed and the second Layers of Ta2θ5 and / or HfO2 are formed.

16. An optoelectronic semiconductor component according to at least one of the above claims, wherein the intermediate layer (2) is a bonding layer.

17. An optoelectronic semiconductor component according to at least one of the above claims, with a coupling-out mirror (13) which is arranged on the side of the component structure (50) facing away from the intermediate layer (2).

18. An optoelectronic semiconductor component according to at least one of the above claims, wherein the output mirror (13) is formed by a metallic mirror.

19. An optoelectronic semiconductor component according to at least one of the above claims, wherein the Auskoppelspiegel (13) is formed by a dielectric mirror.

20. The optoelectronic semiconductor component according to claim 1, wherein the output mirror is formed by a Bragg mirror.

21. An optoelectronic semiconductor device according to at least one of the preceding claims, wherein the output mirror (13) comprises a Bragg mirror containing a plurality of alternating first and second layers, wherein the first layers of SiO 2 and / or AI 2 O 3 are formed and the second Layers of Ta2θ5 and / or HfO2 are formed.

22. The optoelectronic semiconductor component according to claim 1, wherein the distance between the intermediate layer and the outcoupling mirror is at most 10 μm, preferably at most 3 μm, particularly preferably at most 2 μm.

23. Optoelectronic semiconductor component according to at least one of the above claims, in which a contact layer (7) comprising a transparent conductive oxide is arranged between the component structure (50) and the outcoupling mirror (13).

24. An optoelectronic semiconductor component according to at least one of the above claims, wherein the contact layer (7) contains ITO.

25. The optoelectronic semiconductor component according to claim 1, wherein the following relationship is satisfied:

where d is the thickness of the contact layer (7), the wavelength of the electromagnetic radiation generated in the active layer (5), nκ3 ^d i ^e refractive index λ of the material of the contact layer (7) and m is a natural number.