Heavy-power light-emitting diode. RU patent 2247444.
 Heavy-power light-emitting diode / 2247444Proposed light-emitting diode based on nitride compounds of group III metals, that is aluminum, gallium, and indium (AIIIN), includes p-n junction epitaxial structure disposed on insulating substrate and incorporating n and p layers based on solid solutions of group III nitrides AlxInyGa1 - (x + y)N, (0 ≤ x ≤ 1, 0 ≤ y ≤ 1), as well as metal contact pads for n and p layers disposed on side of epitaxial layers, respectively, at level of lower epitaxial n layer and at level of upper epitaxial p layer. Projections of light-emitting diode on horizontal sectional plane, areas occupied by metal contact pad for n layer, and areas occupied by metal contact pad for p layer are disposed on sectional plane of light-emitting diode in alternating regions. Metal contact pad for n layer has portions in the form of separate fragments disposed in depressions etched in epitaxial structure down to n layer; areas occupied by mentioned fragments in projection of light-emitting diode onto horizontal sectional plane are surrounded on all sides with area occupied by metal contact pad for p layer; fragments of metal contact pad for n layer are connected by means of metal buses running over metal contact pad insulating material layer applied to portions of this contact pad over which metal buses are running. |
 Light source with light-emitting component / 2251761Proposed light source emitting light in ultraviolet or blue light region (from 370 to 490 nm) and capable of producing high-efficiency white light affording control of luminance temperature within comprehensive range has light-emitting component that emits light in first spectral region and phosphor of group of optosilicate alkali-earth metals and that absorbs part of source light and emits light in other spectral region. Novelty is that phosphor used for the purpose is, essentially, europium activated bivalent optosilicate of alkali-earth metal of following composition: (2-x-y)SrO · x(Bau, Cav)O · (1-a-b-c-d)SiO2 ·aP2O5bAl2O3cB2O3dGeO2 : yEu2+ and/or (2-x-y)BaO · x(Sru, Cav)O · (1-a-b-c-d)SiO2 ·aP2O5bAl2O3cB2O3dGeO2 : yEu2+. |
 Photoluminescent semiconductor materials / 2255326Porous-structured semiconductor materials are modified by recognition element and exposing to electromagnetic radiation carries out photoluminescence reaction. Recognition elements that can be chosen from bio-molecular, organic and non-organic components interact with target to be subject to analysis. As a result, the modulated photoluminescence reaction arises. |
 Light-emitting diode device / 2258979Proposed device that can be used, for instance, in railway light signals built around light-emitting diodes has one or more photodetectors and set of optical filters additionally disposed on substrate. Each photodetector has its p region connected to its respective wire lead through contact pad; wire lead is passed through substrate hole and insulated from the latter; its n region is connected to its respective wire lead by means of conductor provided with metal or metal-plated contact made in the form of ring segment, all segments being integrated into ring by means of insulating inserts. Set of optical filters having similar or different spectral filtering characteristics is formed by parts of hollow inverted truncated cone whose quantity equals that of photodetectors; all parts are integrated through insulating gaskets into single hollow inverted truncated cone. Disposed on butt-ends of hollow inverted truncated cone are dielectric rings of which upper one has inner diameter equal to that of large base of truncated cone and outer diameter, to that of substrate. Dielectric ring has holes over its circumference for electrical connection of photodetector conductors and light-emitting chips to contacts in the form of ring segments. |
 Semiconductor source of infrared radiation / 2261501Device has emitting surface, recombination area, not less than one passive layer, transparent for emission with hv energy, at least one of layers is made with n-type of conductivity and at least one of said layers is positioned between recombination area and emitting surface, not less than one heat-draining surface and node for connection to outer energy source. Concentration of free carriers (n) and width of forbidden zone (E1) in aforementioned passive layer match relations: |
 Photo-luminescent emitter, semiconductor element and optron based on said devices / 2261502Emitter has electro-luminescent diode of gallium arsenide, generating primary emission in wave length range 0,8-0,9 mcm, and also poly-crystal layer of lead selenide, absorbing primary emission and secondarily emitting in wave length range 2-5 mcm, and lead selenide includes additionally: admixture, directionally changing emission maximum wave length position as well as time of increase and decrease of emission pulse, and admixture, increasing power of emission. Photo-element includes lead selenide layer on dielectric substrate with potential barrier formed therein, and includes admixtures, analogical to those added to lead selenide of emitter. Optron uses emitter and photo-elements. Concentration of addition of cadmium selenide in poly-crystal layer of emitter is 3,5-4,5 times greater, than in photo-element. Open optical channel of Optron is best made with possible filling by gas or liquid, and for optimal synchronization and compactness emitter and/or photo-element can be improved by narrowband optical interference filters. |
 Semiconductor element emitting light in ultraviolet range / 2262155Proposed semiconductor element that can be used in light-emitting diodes built around broadband nitride elements of AIIIBV type and is characterized in ultraviolet emission range extended to 280 -200 nm has structure incorporating substrate, buffer layer made of nitride material, n contact layer made of Si doped nitride material, active layer with one or more quantum wells made of nitride material, barrier layer made of Mg doped AlXGaI-XN, and p contact layer made of Mg doped nitride material; used as nitride material for n contact layer is AlyGaI-yN in which 0.25 ≤ V ≤ 0.65; used as nitride material of active layer is AlZGaI ZN, where V - 0.08 ≤ Z ≤ V - 0.15; in barrier layer 0.3 ≤ X ≤ 1; used as nitride material in p contact layer is AlwGa1 - wN, where V ≤ W ≤ 0.7; active layer is doped with Si whose concentration is minimum 1019 cm-3; width "d" of active layer quantum wells is 1 ≤ d ≤ 4 nm; molar fraction of Al on barrier layer surface next to active layer is 0.6 to 1 and further reduces through barrier layer width to its boundary with p contact layer with gradient of 0.02 to 0.06 by 1 nm of barrier layer thickness, barrier layer width "b" ranging within 10≤ b ≤ 30 nm. |
 Semiconductor element emitting light in ultraviolet range / 2262156Proposed semiconductor element that can be used in light-emitting diodes built around broadband nitride elements of AIIIBV type and is characterized in ultraviolet emission range extended to 240 -300 nm has structure incorporating substrate, buffer layer made of nitride material, n contact layer made of Si doped nitride material AlXIInX2GaI-XI-X2N, active layer made of nitride material AlVIInY2GaI-YI-Y2N, and p contact layer made of Mg doped nitride material AlZIInZ2GaI-ZI-Z2N; active layer is divided into two areas; area abutting against contact layer is doped with Si and has n polarity of conductivity; other area of active layer is doped with Mg and has p polarity of conductivity; molar fraction of Al (YI) in p area of active layer is continuously and monotonously reducing between its boundary with n contact layer and boundary with p area of contact layer and is within the range of 0.1 ≤ VI ≤ 1; difference in VI values at boundaries of active-layer n area is minimum 0.04 and width of forbidden gap in active-layer p area at its boundary with active-layer n area exceeds by minimum 0.1 eV the maximal width of n area forbidden gap. |
 Light-emitting diode incorporating optical component / 2265916Proposed light-emitting diode has chip covered with optical component made of translucent material whose outer surface is of aspherical shape obtained due to rotation of f(x) curve constructed considering optical properties of light-emitting chip and optical component material about symmetry axis of light-emitting diode; it is light-emitting surface. Curve f(x) in coordinate system whose origin point coincides with geometric center of light-emitting chip active area has initial point A0 disposed on ordinate axis at distance corresponding to characteristic size of light-emitting diode; used as this size is desired height of optical component or its desired diameter; active area is formed by plurality of points Ai (i = 1, 2..., n). Taken as coordinates of each point are coordinates of intersection point of straight line coming from coordinate origin point at angle αini to ordinate axis and straight line coming from preceding point Ai - 1 at angle Gi to abscissa axis drawn to point Ai - 1; αini is angle of propagation of iin light beam pertaining to plurality of beams emitted by light emitting chip and chosen between angles 0 and 90 deg.; angle Gi is found from given dependence. |
 Light-emitting diode incorporating optical component / 2265917Proposed light-emitting diode has light-emitting chip covered by optical component made of translucent material whose outer surface is aspherical in shape due to rotation of curve f(x) built considering optical properties of light-emitting chip and optical component material about symmetry axis of light-emitting diode. This surface emits light and f(x) curve in coordinate system whose origin coincides with geometric center of active area of light-emitting diode has initial point A0 disposed on ordinate axis at distance corresponding to characteristic size of light-emitting diode which is, essentially, optical component height or its desired diameter, and is formed by plurality of points A, (i = 1, 2... n); coordinates of intersection point of straight line drawn from coordinate origin point at angle αini to ordinate axis drawn from preceding point Ai - 1 at angle Gi to abscissa axis drawn to point Ai - 1 are taken as coordinates of each of them;; αini is angle of propagation of iin light beam pertaining to plurality of beams emitted by light-emitting chip chosen between 0 and 90 deg. Angle Gi is found from given dependence. Angle αouti is found by pre-construction of directivity pattern DPin of beam emitted by light-emitting chip. Coordinates of A points are checked by means of light-emitting diode simulator that has optical component whose outline is formed by plurality of Ai points as well as light-emitting chip whose beam directivity pattern is DPin; this chip is used as distributed light source having three-dimensional emitting area whose size and appearance correspond to those of emitting area used in light-emitting diode of light-emitting chip. Light emitting points in light-emitting chip of simulator under discussion are offset relative to origin of coordinates within its emitting area; coordinates of Ai points are checked by comparing directivity pattern DPout and directivity pattern DPsim of beam emitted by light-emitting diode simulator, both displayed in same coordinate system. When these directivity patterns coincide, coordinates of points Ai function as coordinates of points forming curve f(x); if otherwise, coordinates of points Ai are found again, and DPoutj is given as directivity pattern DPout whose points are disposed above or below the latter, respectively, depending on disposition of directivity pattern DPsim below or above directivity pattern DPout in the course of check. |
FIELD: semiconductor emitting devices.
SUBSTANCE: proposed light-emitting diode based on nitride compounds of group III metals, that is aluminum, gallium, and indium (AIIIN), includes p-n junction epitaxial structure disposed on insulating substrate and incorporating n and p layers based on solid solutions of group III nitrides AlxInyGa1 - (x + y)N, (0 ≤ x ≤ 1, 0 ≤ y ≤ 1), as well as metal contact pads for n and p layers disposed on side of epitaxial layers, respectively, at level of lower epitaxial n layer and at level of upper epitaxial p layer. Projections of light-emitting diode on horizontal sectional plane, areas occupied by metal contact pad for n layer, and areas occupied by metal contact pad for p layer are disposed on sectional plane of light-emitting diode in alternating regions. Metal contact pad for n layer has portions in the form of separate fragments disposed in depressions etched in epitaxial structure down to n layer; areas occupied by mentioned fragments in projection of light-emitting diode onto horizontal sectional plane are surrounded on all sides with area occupied by metal contact pad for p layer; fragments of metal contact pad for n layer are connected by means of metal buses running over metal contact pad insulating material layer applied to portions of this contact pad over which metal buses are running.
EFFECT: enhanced output optical power and efficiency of light-emitting diode.
3 cl, 3 dwg
The invention relates to the field of semiconductor emitting devices, namely, light emitting diodes on the basis of nitride compounds of metals of group III - aluminum, gallium, indium (III-N).
In recent years, light emitting diodes (LEDs) are increasingly used in lighting, where the key requirement is large optical output power.
The most promising element base lighting LEDs are based epitaxial structures in the system of solid solutions AlInGaN grown on insulating, for example, sapphire (Al 2 O 3 ) a substrate having a Mesa-planar structure, in which the metal pads to the layers of n - and p-type conductivity are arranged from the side of the epitaxial structure.
An essential condition for improving the output power of a light emitting diode is to allow flow through it significant current power provided uniformity of its distribution area p-n junction. At the same time to reduce dzhoulevo losses it is necessary that the light emitting diode has a low electrical resistance, for devices based on AlInGaN structures is a complex task. The latter is due to the fact that, in the present light-emitting diode current goes a long way on a thin (typically, the thickness of 2-3 μm) of the n-GaN conductive layer with a relatively low electrical conductivity [X.Guo, E.Shubert. Current crowding and optical saturation effects in GaInN/GaN LEDs grown on insulating substrates / Appl. Phys, Lett., v.78 (2001), p.3337].
Known led-based epitaxial structure in the system of solid solutions AlInGaN with complex configuration pads [see, for example, patent US 6,307,218 B1], which should provide increased limit values of the supply current and the uniformity of its distribution. Thus, in particular, is known to the decision to patent US 6,518,598 B1, in which to achieve this goal contact pads to the layers of n - and p-type conductivity located respectively at the level of the layers of the n - and p-type conductivity, shaped in the form of "expanding spiral". However, these structures LEDs have very limited opportunities to improve operating currents and thus have a complex topology, which reduces the manufacturability and reliability of the devices.
Known high-power light-emitting diode [patent US 6,521,914], which is selected by the authors as a prototype.
Specified includes led located on the insulating substrate epitaxial structure with a p-n junction containing layers of n - and p-type conductivity, on the basis of solid solutions of nitrides of metals of the third group Al x In y Ga 1-(x+y) N (0≤x≤1, 0≤y≤l). The led has a Mesa-planar structure with the radiation through the substrate and contains located on the lower epitaxial layer of n-type conductivity metal contact pad to a layer of n-type conductivity and located at the level of the upper epitaxial layer of p-type conductivity metal contact pad to a layer of p-type conductivity. In the projection on the horizontal plane of the cross section of the led area occupied by the metal contact pad to a layer of n-type conductivity, and the area occupied by the metal contact pad to a layer of p-type conductivity, are sectional area of the led alternating stripes, forming interdigital (comb-like) configuration.
Consider the led provides the ability to pass significant current (up to 1A) and has a relatively low electrical resistance (about 1 Ohm), which allows to reach high enough values of the output power and efficiency. However, in this arrangement, the led pad to a layer of n-type conductivity is made in the form of a set of long strips, which leads to the loss of a significant part of the active area of the led (square p-n junction), which limits the possibilities of improving these energy parameters of the considered semiconductor light source.
The task of the invention is to increase the output power and efficiency of a light emitting diode.
The essence of the invention lies in the fact that in the light-emitting diode, which includes located on the insulating substrate epitaxial structure with a p-n junction containing layers of n - and p-type conductivity on the basis of solid solutions of nitrides of metals of the third group Al x In y Ga 1-(x+y) N (0≤x≤1, 0≤y≤
1), a metal contact pads to the layers of n - and p-type conductivity spaced from the side of the epitaxial layers respectively on the lower epitaxial layer of n-type conductivity and at the level of the upper epitaxial layer of p-type conductivity, and the projection on the horizontal plane of the cross section of a light emitting diode region occupied by the metal contact pad to a layer of n-type conductivity, and the area occupied by the metal contact pad to a layer of p-type conductivity, are located on the sectional area of the light-emitting diode alternating zones, according to the invention the metal contact surface to the layer of n-type conductivity has parts made in the form of separate fragments located in the grooves, etched in the epitaxial structure to a layer of n-type conductivity, and the projection on the horizontal plane of the cross section of a light emitting diode region occupied by the specified fragments, surrounded on all sides by the area occupied by the metal contact pad to a layer of p-type conductivity, with fragments of metal pads to the n-layer conductivity electrically connected with the metal of the tire passing over the contact metal pad layer to p-type conductivity over the layer of dielectric material deposited on the areas specified contact pads on which are metal tires.;
A possible embodiment of the invention, in which each of the fragments of metal pads to the layer of n-type conductivity is circular, these fragments in the projection on the horizontal plane of the sectional light emitting diodes are uniformly distributed over the cross-sectional area of the light-emitting diode rows.
A possible embodiment of the invention, in which the metal contact surface to the layer of p-type conductivity has a square shape, and the metal pad layer of n-type conductivity includes four fragments, each of which has a g-shaped, these fragments are located so that the projection on the horizontal plane of the sectional light emitting diode they form in the Central part of the cross-sectional area of the light-emitting diode corners of the square.
Due to the fact that the metal contact surface to the n-layer conductivity has parts made in the form of separate fragments, arranged in such a way that the projection on the horizontal plane of the cross section of the led, the area occupied by the specified fragments, interspersed with areas occupied by the metal contact pad to a layer of p-type conductivity, and surrounded these areas from all sides, is achieved (even for LEDs large size) uniform injection current in the region of the p-n junction and, accordingly, is provided close to the uniform distribution of current over the area of the p-n junction. However through the use of metal tyres, electrically connecting the individual pieces laid on a layer of dielectric over the metal pads to the layer of p-type conductivity, a large area of the active region of the led and decreases the electrical resistance associated with the current flowing along the metal contacts to the n-region. The combination of these factors provides increased output optical power per unit area of the inventive light-emitting diode.
Figure 1 presents a General view drawing of a light emitting diode (top view) when pieces of metal pads to the layer of n-type conductivity are round in shape; figure 2 - the same (section a-a and section B-B in figure 1); figure 3 shows an embodiment of a light emitting diode in the case where pieces of metal pads to the layer of n-type conductivity are d-shaped.
Light-emitting diode includes a substrate 1 made, in particular, from the sapphire epitaxial structure on the basis of solid solutions of nitrides of metals of the third group Al x In y Ga 1-(x+y) N (0≤x≤1, 0≤≤1)grown by means of vapor-phase epitaxy from ORGANOMETALLIC compounds on the substrate 1. The epitaxial structure includes nearest to the substrate conductive layer 2 of n-type conductivity (n-GaN), an active layer 3 (In x Ga 1-x N), including p-n junction, a blocking layer 4 (p-Al x Ga 1-x N) and a contact layer 5 of p-type conductivity (p-GaN). Light-emitting diode also includes a metal contact pad 6 to the layer of p-type conductivity and a metal contact pad 7 to the layer of n-type conductivity.
The light-emitting diode, are presented in figures 1, 2 pad 6 has a horizontal cross-section of the led rectangular in shape and occupies almost the entire area of the led. Contact pad 7 is formed by a stripe running along one side pads 6 and located in the appropriate form the recess vitravene in the epitaxial structure to the level of layer 2 of n-type conductivity and having a circular fragments located in the grooves, etched to the level of layer 2. These fragments in the projection on the horizontal plane of the cross section of the led are uniformly distributed over the area of the led rows and electrically connected to the land pad 7 made in the form of a strip, and each other with metal tyres 8, passing through the layer 9 of a dielectric material (e.g., magnetron SiO 2 ), is applied in the form of strips on the areas of the pads 6 where above them are the metal wire 8.
The light-emitting diode is presented on figure 3, the contact pad 6 has a horizontal cross-section of the led is the shape of a square and occupies almost the entire area of the led. Contact pad 7 is formed by a strip located on the perimeter of the pad 6 in the appropriate form the recess vitravene in the epitaxial structure to the level of layer 2 of n-type conductivity, and four fragments, each of which has a g-shaped, located in the grooves, etched to the level of layer 2. These fragments are located so that the projection on the horizontal plane of the cross section of the led, they form a Central part of the square cross section of the led corners of the square. The fragments are electrically connected with metal tyres 8 with a plot of the contact pad 7 made in the form of stripes.
Over those sections of the pads 6, which laid the metal wire 8, a layer 9 of a dielectric material.
The device operates as follows.
While supplying the electric power to the light emitting diode current from the pad 6 through the layers 5, 4, 3 and layer 2 epitaxial patterns flows to the pad 7. In the active layer 3, which is the p-n junction, the current flow results in the generation of light radiation.
Due to the fact that the contact layer 5 of p-type conductivity and a blocking layer 4 have much lower conductivity than the conductive layer 2 of n-type conductivity, current practically does not spread in layers 5 and 4, and flows vertically down to the active layer 3 (area p-n junction), and the region generating light geometrically repeats the area occupied by the contact pad 6 to the layer of p-type conductivity. Since in the present light-emitting diode, the area occupied by fragments of the pads 7, is small relative to the area occupied by the contact pad 6, and for the electrical connection of the fragments used metal wire 8 is placed on top of the pads 6, the proportion of the area occupied by the contact pad 6 to the layer of p-type conductivity in the General area of the led, and hence, increases the active area, where the generation of light. The cross section of the metal tire 8 can be chosen large enough, due to which removed restrictions on minimizing the electrical resistance associated with the contact n-region. By choosing the shape, the number of fragments pads to a layer of n-type conductivity, as well as their distribution over the area of the led can achieve a high degree of uniformity of the current distribution, and, consequently, to increase the supply current, and hence, to increase the optical output power and efficiency of the inventive semiconductor device.
Thus, in particular, to a light-emitting diode, the design of which is presented in figure 3, had the following characteristics of the device: the area is an active area of 1 mm 2, the value of the direct current was 2 A, and a value of electric resistance of 0.7 Ohms, which provided high optical output power and high efficiency of this light-emitting device.
1. Light-emitting diode, which includes located on the insulating substrate epitaxial structure with a p-n junction containing layers of n - and p-type conductivity on the basis of solid solutions of nitrides of metals of the third group Al x In y Ga 1-(x+y) N (0≤x≤1, 0≤≤
1)and the metal pads to the layers of n - and p-type conductivity spaced from the side of the epitaxial layers respectively on the lower epitaxial layer of n-type conductivity and at the level of the upper epitaxial layer of p-type conductivity, and the projection on the horizontal plane of the cross section of a light emitting diode region occupied by the metal contact pad to a layer of n-type conductivity, and the area occupied by the metal contact pad to a layer of p-type conductivity, are located on the sectional area of the light-emitting diode alternating zones, characterized in that the metal contact surface to the layer n-type conductivity has parts made in the form of separate fragments located in the grooves, etched in the epitaxial structure to a layer of n-type conductivity, and the projection on the horizontal plane of the cross section of a light emitting diode region occupied by the specified fragments, surrounded on all sides by the area occupied by the metal contact pad to a layer of p-type conductivity, with fragments of metal pads to the n-layer conductivity electrically connected with the metal of the tire passing over the contact metal pad layer to p-type conductivity over the layer of dielectric material deposited on the areas specified contact pads, on which are the metal wire.;
2. Light-emitting diode according to claim 1, characterized in that each of the fragments of metal pads to the layer of n-type conductivity is circular, these fragments in the projection on the horizontal plane of the sectional light emitting diodes are uniformly distributed over the cross-sectional area of the light-emitting diode rows.
3. Light-emitting diode according to claim 1, characterized in that the metal contact surface to the layer of p-type conductivity has a square shape, and the metal contact surface to the layer of n-type conductivity includes four fragments, each of which has a G-shaped, these fragments are located so that the projection on the horizontal plane of the sectional light emitting diode they form in the Central part of the cross-sectional area of the light-emitting diode corners of the square.