Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L33/44—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the coatings, e.g. passivation layer or anti-reflective coating
  • H01L33/46—Reflective coating, e.g. dielectric Bragg reflector
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L33/44—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the coatings, e.g. passivation layer or anti-reflective coating
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L33/36—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the electrodes
  • H01L33/38—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the electrodes with a particular shape
  • H01L33/387—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the electrodes with a particular shape with a plurality of electrode regions in direct contact with the semiconductor body and being electrically interconnected by another electrode layer
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
  • H01L33/36—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the electrodes
  • H01L33/40—Materials therefor
  • H01L33/42—Transparent materials
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
  • H01S5/00—Semiconductor lasers
  • H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
  • H01S5/1046—Comprising interactions between photons and plasmons, e.g. by a corrugated surface

Definitions

• An optoelectronic semiconductor component is specified.
• the absorption length is thereby of the same order of magnitude as the structure size of the structured metal layer. For this reason, the effect of nanostructuring, that is, the improvement of the output of the light generated in the light-emitting diode is significantly reduced.
• An object to be solved is to provide an optoelectronic semiconductor device having improved efficiency.
• the semiconductor component comprises a semiconductor body.
• the semiconductor body has at least one active region, which is provided for generating electromagnetic radiation. That is, in the operation of the optoelectronic semiconductor device is in active area generates electromagnetic radiation.
• the electromagnetic radiation leaves the semiconductor body through a radiation passage area.
• the radiation passage area is formed by a part of the outer surface of the semiconductor body.
• the optoelectronic semiconductor component comprises an intermediate layer.
• the intermediate layer is preferably directly on the
• Radiation passage surface of the semiconductor body arranged. That is, preferably, the intermediate layer adjacent to the semiconductor body and thus to a semiconductor material.
• the intermediate layer has a lower optical refractive index than the semiconductor material to which it is adjacent. This means that generated during operation of the semiconductor body electromagnetic radiation occurs at the radiation passage area of the semiconductor body from the optically denser medium - a semiconductor material of the semiconductor body - in the optically thinner medium - in the material of the intermediate layer.
• the optoelectronic component further comprises a structured metal layer.
• the structured metal layer is arranged on the surface of the intermediate layer opposite to the semiconductor body.
• the structured metal layer is preferably arranged directly on the intermediate layer.
• the semiconductor component comprises a semiconductor body having a radiation passage area comprises, an intermediate layer, which is arranged directly on the radiation passage area of the semiconductor body and has a lower optical refractive index than the adjacent semiconductor material of the semiconductor body, and a structured metal layer which is arranged on the surface of the intermediate layer opposite the semiconductor body.
• Radiation passage area of the semiconductor body is arranged, the overlap of the plasmon mode is reduced with the metal of the patterned metal layer. As a result, the absorption of electromagnetic radiation generated in the semiconductor body is reduced. That is, the
• a surface plasmon is created at the junction of the intermediate layer and the structured metal layer.
• plasmons it is possible for plasmons to contribute, since the coupling between the plasmon and the photon takes place over a periodic period
• the periodicity of the structuring of the structured metal layer determines the direction of propagation of the photons, with which the coupling is the largest.
• the shape of the structuring determines whether this is done for all or only one direction of polarization.
• symmetric structuring such as circular or square holes in a metal layer, there is no polarization dependence.
• elliptical or rectangular holes or in extreme cases strip grids - a coupling takes place only for one polarization direction.
• the mechanism of the modification of the emission direction or the polarization can hereby be a mere filtering, that is, electromagnetic radiation which is not emitted with the desired characteristic is absorbed or reflected. In the case of reflection, this electromagnetic radiation can then, for example, by scattering processes in the semiconductor body of the optoelectronic
• Recycled means that the reflected electromagnetic radiation is absorbed, for example, in an active region of the optoelectronic semiconductor component and then re-emitted.
• Another possible mechanism - apart from absorption and reflection - is the change in the propagation direction of the electromagnetic radiation through the plasmons.
• An increase in the efficiency of the optoelectronic semiconductor component in its application can also be achieved by generating a modified emission characteristic or a linear polarization of the emitted electromagnetic radiation via the plasmons and only or preferably using the electromagnetic radiation in the application of the optoelectronic semiconductor component this particular radiation characteristic - that is, the particular radiation direction and / or polarization - can be used.
• Examples include a projection system for a forward-emitting LED, an LCD backlight for a polarized light-emitting diode and / or an LCD projector for a polarized and forward-emitting light emitting diode.
• the intermediate layer contains a dielectric material. Further, it is possible that the intermediate layer is made of a dielectric material. Preferably, the dielectric material is silicon dioxide. That is, the intermediate layer contains or consists of silicon dioxide.
• dielectric materials and in particular silicon dioxide due to their low optical refractive index, are particularly well suited for reducing the overlap of the plasmon mode with the metal and thus the absorption of electromagnetic radiation.
• the intermediate layer contains a transparent, electrically conductive oxide (TCO).
• TCO transparent, electrically conductive oxide
• the intermediate layer can then consist of one of the following materials or contain at least one of the following materials: indium zinc oxide, indium tin oxide, zinc oxide.
• a transparent, electrically conductive oxide can be realized with the intermediate layer in addition to the advantageous reduction of the overlap of the plasmon mode with the metal of the patterned metal layer, an electrical contact for the optoelectronic semiconductor device.
• the efficiency of the optoelectronic semiconductor component can be increased by using the plasmonic structure as a transparent contact. This is the case, for example, if the intermediate layer contains or consists of a transparent electrically conductive oxide.
• the structured metal layer increases the lateral conductivity of the intermediate layer and the structuring of the metal layer creates a transparency.
• the intermediate layer comprises a layer sequence with at least two layers.
• the layers of the layer sequence are preferably arranged parallel or substantially parallel to the radiation passage area of the semiconductor body.
• the layers of the layer sequence are then arranged one above the other in the sense of a layer stack.
• the optical refractive index of the layers of the layer sequence decreases from the layer which is closest to the radiation passage area to the layer which lies closest to the structured metal layer.
• the intermediate layer comprises a layer sequence with at least two layers, wherein the optical refractive index of the layers decreases from the radiation passage area of the semiconductor body in the direction of a structured metal layer.
• the intermediate layer comprises a layer sequence with two layers, the first layer adjoining the radiation passage area consisting of a transparent electrically conductive oxide and the second layer consisting of silicon dioxide.
• the second layer preferably adjoins the structured metal layer. That is, the patterned metal layer is disposed on the second layer.
• the second layer which consists of silicon dioxide
• the second layer recesses or openings, in which electrical contacts to the first layer are arranged.
• the second layer has recesses, which are filled, for example, with an electrically conductive material such as a metal or a transparent, electrically conductive oxide.
• an electrical contact between the first layer, which consists of a transparent electrically conductive oxide and, for example, a contact point of the optoelectronic semiconductor device mediates.
• the intermediate layer comprises a
• the first, adjacent to the radiation passage area layer consists of a first transparent electrically conductive oxide and the second layer, which preferably adjacent to the patterned metal layer, consists of a second transparent electrically conductive oxide.
• the first layer preferably establishes the electrical contact with the semiconductor body and optionally provides the largest part the transverse conductivity of the intermediate layer, that is the conductivity in the direction parallel to the radiation passage area.
• the second layer is advantageously distinguished by a particularly good transparency for the electromagnetic radiation generated in the semiconductor body. That is, the second layer preferably has a very low absorption coefficient.
• a transparent, electrically conductive oxide having a reduced relative to the first layer electrical conductivity is sufficient for the second layer.
• ITO indium tin oxide
• ZnO highly doped zinc oxide
• the second layer then preferably consists of a low-doped zinc oxide or a zinc oxide deposited with the addition of oxygen. Oxygen addition during the deposition of, for example, an aluminum-doped zinc oxide oxidizes the aluminum, thereby no longer acting as a dopant and effectively reducing the aluminum content.
• the zinc oxide is preferably doped with aluminum and / or gallium.
• the doping of the zinc oxide causes an increase in the absorption of the optoelectronic
• the structured metal layer of the semiconductor component is designed such that electromagnetic radiation generated in operation in the semiconductor body excites surface plasmons.
• the structured metal layer can be structured in the manner of a one-dimensional grid, that is, it is formed by metal strips that run parallel to each other. Furthermore, the structured metal layer can be structured in the manner of a two-dimensional grid. This may be, for example, a hexagonal grid or a rectangular grid. Furthermore, the patterning of the structured metal layer may be quasiperiodic, that is, not periodic but ordered, for example in the manner of Fibonacci numbers or the golden section. Furthermore, a statistical or random
• the size of the metal structures is in the range of the wavelength of the electromagnetic radiation emitted by the optoelectronic semiconductor component during operation. That is, the spacing of the metal structures is in the range between 50 and 1000 nm and the size of the metal structures is between 10 and 90% of the total area. That is, the area of the metal structures is between 10 and 90% of the area of the area to which the
• the structured metal layer contains at least one of the the following metals or consists of one of the following metals: gold, silver, aluminum.
• silver is particularly well suited for use with a GaN-based semiconductor body.
• Aluminum is particularly well suited for Hägeriter Equity based on AlGaAs or InGaAlP.
• the structured metal layer has a thickness of at least 20 and at most 200 nm.
• the structured metal layer can also serve as part of a contact layer, via which electrical current for the operation of the optoelectronic semiconductor component is impressed into the semiconductor body.
• a dielectric layer which consists of a dielectric material is arranged on the side of the structured metal layer facing away from the semiconductor body.
• the dielectric layer is formed of the same material as the intermediate layer.
• the dielectric layer may comprise more than one dielectric layer.
• the dielectric layer may be disposed directly on the patterned metal layer and / or the intermediate layer.
• FIG. 1 shows a schematic sectional view of an optoelectronic device described here Semiconductor device according to a first embodiment.
• FIG. 2 shows a schematic sectional view of an optoelectronic device described here
• FIG. 3 shows a schematic sectional view of an optoelectronic device described here
• FIG. 4 shows a schematic plot of the penetration depth ⁇ 3 relative to the penetration depth ⁇ 4 against the optical refractive index n4.
• FIG. 5 shows a schematic plot of the
• Propagation length L as a function of the optical refractive index n4.
• FIG. 6 shows a schematic sectional representation of an optoelectronic semiconductor component described here according to a fourth exemplary embodiment.
• FIG. 1 shows a schematic sectional illustration of an optoelectronic semiconductor component described here according to a first exemplary embodiment.
• the optoelectronic semiconductor component comprises a semiconductor body 1.
• the semiconductor body contains, for example, cladding layers 10, 12 and an active region 11.
• electromagnetic radiation is generated in the active region 11, which generates the
• Semiconductor body 1 leaves through its radiation passage area 2.
• a contact layer 6 is provided, which is provided, for example, for the p- or n-side contacting of the optoelectronic semiconductor component.
• the optoelectronic semiconductor component is a light-emitting diode, that is to say a laser diode or a light-emitting diode. It is preferably a thin-film light-emitting diode.
• Thin-film light-emitting diode chips 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.
• the intermediate layer 4 consists of a material which has a lower optical refractive index n 4 than the semiconductor material bordering it, that is to say, for example, the material of the cladding layer 10.
• the structured metal layer 3 contains or consists of at least one of the following metals: gold, silver, aluminum.
• the thickness DM of the metal layer 3 is preferably at least 20 nm and at most 200 nm.
• the structured metal layer 3 consists for example of metal strips which are parallel to each other on the
• Semiconductor body 1 facing away from the surface of the intermediate layer 4 are arranged.
• the optoelectronic semiconductor component is a light-emitting diode based on the InGaN material system.
• the optoelectronic semiconductor component is suitable in operation for generating green light.
• the structured metal layer 3 is made of silver.
• the structured metal layer 3 is designed in the manner of a two-dimensional grid.
• the two-dimensional lattice is a hexagonal lattice, at the lattice points of which cylindrical recesses are arranged in the metal layer.
• the spacing of the recesses is preferably between 170 and 330 nm.
• the radius of the recesses is preferably between 80 and 170 nm.
• the height of the recesses is 50 nm.
• the thickness of the intermediate layer 4 is 5 nm, the thickness of the structured metal layer DM is 50 nm.
• the intermediate layer 2 consists of silicon dioxide. Silicon dioxide is particularly well-suited because of its low absorption and its low optical refractive index as an intermediate layer for reducing the overlap of the plasmon mode with the metal.
• the intermediate layer 4 consists of an electrically conductive and transparent oxide (TCO). This is at the same time to reduce the
• zinc oxide is particularly preferably used as the material of the intermediate layer 4 as material for the intermediate layer 4 because of its low optical absorption in the largest part of the visible spectral range.
• the intermediate layer 4 comprises two individual layers 4a and 4b.
• the first layer 4a which has a higher optical refractive index than the second
• Layer 4b directly on the semiconductor body 1.
• the lying directly on the structured metal layer 3 second layer 4b has the lowest possible optical refractive index.
• the intermediate layer 4 consists of a layer sequence of more than two layers, wherein the optical refractive index of a layer is the lower, the farther the layer of the semiconductor body 1 is located.
• the first layer 4a consists of a transparent, electrically conductive oxide, which ensures its electrical transverse conductivity for the electrical connection of the optoelectronic semiconductor device.
• the second layer 4b is then preferably made of silicon dioxide.
• the second layer 4b then has recesses 5, through which the surface is locally plated on the first layer 4a.
• the recesses 5 are, for example, with the metal of the structured
• the first layer 4a is formed from a first transparent electrically conductive oxide and the second layer 4b is formed from a second, different from the first transparent electrically conductive oxide.
• the material of the first layer 4a has a greater transverse conductivity and optionally a lower transparency than the material of the second
• the first layer consists for example of ITO or highly doped ZnO, while the second layer then consists of low-doped ZnO or a ZnO deposited with oxygen addition.
• FIG. 2 shows a sectional representation of an optoelectronic semiconductor component described here according to a second exemplary embodiment.
• the optoelectronic component according to the second exemplary embodiment differs from the optoelectronic component described in conjunction with FIG. 1 in that the radiation passage area 2 is roughened in this exemplary embodiment.
• the intermediate layer 4 is designed as in one of the examples described in connection with FIG. The intermediate layer 4 serves in this
• the preferred structure size for the roughening is between 100 and 2000 nm.
• FIG. 3 shows a schematic sectional representation of an optoelectronic component according to a third exemplary embodiment described here.
• the side of the intermediate layer 4 facing away from the structured, roughened radiation passage area 2 is also structured.
• the intermediate layer 4 is designed according to one of the examples described in connection with FIG. The structuring of the intermediate layer 4 makes it possible to influence the coupling of the electromagnetic radiation generated in the semiconductor body to the plasmon mode.
• the one grating is provided by the structured metal layer 3 and the other by the structured surface of the intermediate layer 4.
• the structure size for the structuring of the surface of the intermediate layer 4 is preferably between 50 and 1000 nm.
• the structuring of the intermediate layer 4 may take place for example by one of the following methods: focused ion beam (FIB) , Electron beam lithography, nano-imprint, optical lithography or other structuring techniques.
• Penetration depth ⁇ 3 in the structured metal layer relative to the penetration depth ⁇ 4 in the intermediate layer 4 against the optical refractive index n4 of the intermediate layer 4 for two different peak wavelengths of the electromagnetic radiation generated in the semiconductor body 1 applied. From this plot it can be seen that the penetration depth into the structured metal layer decreases relative to the penetration depth into the intermediate layer 4 with decreasing refractive indices n4.
• silver was assumed to be the metal of the structured metal layer 3.
• FIG. 5 shows, in a schematic plot, the propagation length L for two peak wavelengths of the electromagnetic radiation generated in the semiconductor body as a function of the optical refractive index n4 of the intermediate layer 4.
• the propagation length L is greater for both selected wavelengths-450 nm and 650 nm The smaller the refractive index n4 of the intermediate layer 4 of the material of the intermediate layer 4 is.
• the propagation length is understood as the distance covered by the surface plasmon before it is due to the absorption losses has fallen to the 1 / e-th part of the initial intensity. That is, the higher the absorption length, the lower the absorption loss. Thus, more electromagnetic radiation can be coupled out by scattering on the structured metal layer 3 than in a system with higher absorption.
• FIG. 6 shows a schematic sectional illustration of an optoelectronic component according to a fourth exemplary embodiment described here.
• the radiation passage areas 2 of the semiconductor body 1, the intermediate layer 4 and the structured metal layer 3 are structured.
• On the side facing away from the semiconductor body 1 of the structured metal layer 3 further layers 41, 42 are arranged, which consist of a dielectric material.
• the intermediate layer 4 is preferably made of a dielectric in this embodiment.
• the dielectric layers 4, 41, 42 may also be formed in this embodiment as any layer sequences of different dielectric materials.
• the transition between the dielectric layer 41 and the air does not necessarily have to be smooth, but may also be structured.
• the surface of the dielectric layer 41 facing away from the semiconductor body 1 may be roughened periodically or not periodically.
• the dimension of the structuring of the structured metal layer 3 and of the dielectric layers 4, 41, 42 lies in the region of the wavelength of the electromagnetic radiation generated by the optoelectronic semiconductor component during operation.
• the layer thicknesses of the dielectric layers 4, 41 can be of a few nanometers up to several microns.
• the thickness of the structured metal layer and thus the thickness of the dielectric layer 42 is preferably between 20 nm and 200 nm.
• the three dielectric layers 4, 41, 42 consist of one and the same material, for example silicon dioxide.

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• 2008
  • 2008-01-04 DE DE102008003182A patent/DE102008003182A1/de not_active Withdrawn
  • 2008-12-22 WO PCT/DE2008/002150 patent/WO2009086808A1/de active Application Filing
  • 2008-12-25 TW TW97150639A patent/TW200935632A/zh unknown

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