CN201349018Y

CN201349018Y - Distribution of current barrier layer and light-emitting diode corresponding to top electrode

Info

Publication number: CN201349018Y
Application number: CNU2008201236100U
Authority: CN
Inventors: 沈光地; 陈依新
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-11-07
Filing date: 2008-11-07
Publication date: 2009-11-18
Anticipated expiration: 2018-11-07

Abstract

The utility model relates to the distribution of a current barrier layer and a light-emitting diode corresponding to a top electrode, and belongs to the technical field of semiconductor optoelectronics. The light-emitting diode comprises a top electrode (10), a current expansion layer (100), an upper limiting layer (300), an active region (200), a lower limiting layer (400), a buffer layer (500), a substrate (600) and a lower electrode (20), wherein a conductive light trapping layer (101) is arranged between the top electrode and the current expansion layer, and the shape of a current barrier layer (120) which is positioned under the top electrode is the same as the shape of the top electrode; and the current barrier layer is arranged in the conductive light trapping layer, the current expansion layer, the upper limiting layer or the active region, or the two adjacent layers, the three adjacent layers or the four adjacent layers. The structure is realized by post process, the process is simple, and the current barrier layer corresponding to the top electrode almost completely avoids the light and heat loss generated by idle current, thus improving the efficiency of LED light extraction, and increasing the luminous intensity; and the device is more favorable for working under large current, and the structure greatly reduces the generation of heat, and is particularly suitable for preparing high-power LEDs.

Description

The light-emitting diode that the distribution of current barrier layer is corresponding with top electrode

Technical field

The distribution of the current barrier layer light-emitting diode corresponding with top electrode relates to a kind of new LED device architecture, belongs to field of semiconductor photoelectron technique.

Background technology

At present, common light-emitting diode structure as shown in Figure 1: top electrode 10 is that 80-100 μ m, thickness are about for diameter

Above circular metal layer, from this electrode injection current, the photon of generation comes out from this surface launching of LED; Bottom electrode 20 is the whole surface size of LED device, and thickness approximately

Above metal level, the subject matter that the LED of this structure exists is: the electric current of the utmost point 10 injections from power on produces photon by active area 200 radiation recombination of flowing through extending transversely of current extending 100, because present growth technology is difficult to obtain highly doped, the current extending that thickness is thicker, cause the lateral current of current extending indifferent, therefore, from power on the electric current overwhelming majority injected of the utmost point 10 collect in top electrode 10 under, for example: for the chip size of positive bright dipping is that the AlGaInP of 300 μ m*300 μ m is a red-light LED, the GaP current extending of MOCVD (Metal Organic Chemical Vapor Deposition) epitaxial growth 8 μ m, if the diameter of top electrode 10 is 100 μ m, as calculated as can be known: the electric current under the top electrode 10 accounts for more than 40% of total injection current.The photon that this part electric current produces in active area 200 radiation recombination under the top electrode 10 is because stopping or absorb by top electrode 10, not only can not be transmitted into external, and be absorbed and produce a large amount of heat in vivo, have a strong impact on the further raising of LED performance, therefore, for the LED of this kind structure, there are problems such as luminous efficiency is low, luminous power is less, thermal characteristics difference.

At this problem, the way that people propose: preparation current barrier layer 120 under top electrode 10, reduce the current ratio under the top electrode 10, the preparation method and the structure of current barrier layer are a lot, and Fig. 2, Fig. 3 have enumerated the structure and the method for several preparation current barrier layers.Structure shown in Figure 2 is that the method by secondary epitaxy realizes, after the good current barrier layer 120 of prepared such as photoetching, and epitaxial growth current extending 100 and prepare top electrode 10 above it again, this complex process, cost height, rate of finished products are low.Structure shown in Figure 3 is to carry out ion to inject or diffuse to form barrier layer 120 on the thick current extending that current extending 100 and contact layer 102 are constituted, the thickness of the current barrier layer 120 in the method is difficult to accurately control, still there is current expansion its below, thereby can not block current flow converging below electrode 10, and thick current extending (8-50 μ m) and ion inject and the diffusion technology complexity, the cost height.

Above-mentioned 2 kinds of device architectures have all only been mentioned preparation current barrier layer 120 under the pressure welding point of top electrode 10, in fact, for most of device, particularly powerful device, the shape of its top electrode 10 is not only the circle of pressure welding point, but can have very complicated shape to increase the expansion of electric current, and being referred to as pattern electrodes, Fig. 4, Fig. 5 have enumerated the shape of several frequently seen LED top electrode 10.Still can compile the part electric current under the top electrode 10, even greater than the electric current (area of view shape electrode and the ratio of pressure welding point area) that compiles below the pressure welding point, the photon that this part electric current produces at active area 200 still can be caused problems such as the device light efficiency is low, brightness is low, thermal characteristics difference by the stopping or absorb and become a large amount of heat of top electrode 10.

Summary of the invention

The purpose of this utility model provides a kind of distribution light-emitting diode corresponding with top electrode of current barrier layer, its basic structure as shown in Figure 7, it is to introduce the current barrier layer structure under the top electrode of light-emitting diode, and the distribution of current barrier layer is corresponding with top electrode, make that active area 200 radiation recombination of injection current beyond under top electrode 10 are luminous, the photon that produces is avoided stopping of top electrode 10 or is absorbed, and current barrier layer 120 is realized by back technology, workable, this structure is suitable for the preparation of great power LED most, improved light extraction efficiency, reduced hot generation, avoid the cooling measure of the complexity that great power LED takes, also greatly reduced the heat radiation cost.

Device architecture of the present utility model as shown in Figure 7, its part comprises: include from top to bottom top electrode 10, current extending 100, upper limiting layer 300, active area 200, lower limit layer 400, resilient coating 500, substrate 600, the bottom electrode 20 of the storied length of longitudinal layer successively, also include the current barrier layer 120 that is positioned at the top electrode below, the utility model is characterised in that: be provided with conductive light antireflection layer 101 between top electrode and current extending, and the distribution of current barrier layer is corresponding with top electrode.

The shape of current barrier layer 120 is identical with top electrode 10 shapes in the utility model, size also can greater than, be equal to or less than the size of top electrode.

Current barrier layer 120 is arranged on conductive light antireflection layer 101 or current extending 100 or upper limiting layer 300 or active area 200 the insides in the utility model, or simultaneously in conductive light antireflection layer 101 and current extending 100 the insides, or simultaneously at conductive light antireflection layer 101, current extending 100 and upper limiting layer 300 the insides, or simultaneously at conductive light antireflection layer 101, current extending 100, upper limiting layer 300 and active area 200 the insides, or simultaneously in current extending 100 and upper limiting layer 300 the insides, or simultaneously at current extending 100, upper limiting layer 300 and active area 200 the insides, or simultaneously in upper limiting layer 300 and active area 200 the insides.

The top setting of conductive light antireflection layer 101 can be played the structure sheaf of anti-reflection effect to light in the utility model, and this structure sheaf is one deck anti-reflection film 103 or handles at conductive light antireflection layer 101 upper surfaces or anti-reflection film 103 upper surfaces and to form the roughened textures layer.

The distribution of the current barrier layer of the LED structural design advantage corresponding with top electrode is in the utility model: because the existence of current barrier layer 120, the injection current nature flow to active area beyond the current barrier layer 120, make that no current is not luminous under the top electrode 10, played the effect that all stops; Acting as of conductive light antireflection layer: the one, because the design of material refractive index and thickness, make the photon that produces in the body is played anti-reflection effect, more photon can be transmitted into external, and has increased the expansion of electric current, so, greatly reduce the thickness of current extending 100; The preparation of this structure realizes by back technology, epitaxially grown thickness and difficulty have been reduced, technology is simple, workable, compare with the current barrier layer of general pressure welding point below, this barrier structure can really play the effect that all stops, thereby improves luminous intensity and the thermal characteristics of LED, especially is fit to and the preparation high-power LED.

Main feature of the present utility model:

1) distribution of the current barrier layer of the LED structure corresponding with top electrode can be effectively even fully stoped the electric current under the top electrode to flow, and the active area radiation recombination under other electrodeless zone correspondences is luminous, the photon that produces has been avoided stopping of electrode or has been absorbed, thereby has improved light extraction efficiency and the luminous intensity of LED.

2) avoided converging of electric current under the top electrode, reduced a large amount of photons that produce in the body and can't be transmitted into externally and become a large amount of heat, therefore, improved saturation current and the thermal characteristics of LED, made that device more helps working under big electric current at device inside.

3) the current barrier layer structure realizes that by back technology technology is simple, and is workable.

4) reduce epitaxially grown thickness, reduced the difficulty of growth.

5) distribution of the current barrier layer of introducing LED and the structure that electrode pair is answered, significant advantage is: current loss is little, brightness height, light efficiency height; Manufacture craft is simple, good reproducibility; Be particularly suitable for the preparation of high power device.

Description of drawings:

Fig. 1: common light emitting diode construction schematic diagram

Fig. 2: secondary epitaxy prepares the light emitting diode construction schematic diagram of current barrier layer

Fig. 3: ion injection or diffusion technology prepare the light emitting diode construction schematic diagram of current barrier layer

Fig. 4: electrode pattern schematic diagram-1

Fig. 5: electrode pattern schematic diagram-2

Fig. 6: the light emitting diode construction schematic diagram that has the conductive light antireflection layer

Fig. 7: the light emitting diode construction profile that the distribution of current barrier layer is corresponding with top electrode

Fig. 8: the light emitting diode construction stereogram that the distribution of current barrier layer is corresponding with top electrode

Among above Fig. 1 to Fig. 8: 10 is top electrode, and 100 is current extending, and 101 is the conductive light antireflection layer, and 102 is contact layer, 103 is anti-reflection film, and 300 is upper limiting layer, and 200 is active area, and 400 is lower limit layer, 500 is resilient coating, and 600 is substrate, and 120 is current barrier layer, and 20 is bottom electrode.

Embodiment

Realization of the present utility model is described by following examples.

Embodiment 1

As shown in Figure 7, be example with AlGaInP LED.This device is made up of following each several part: top electrode 10, conductive light antireflection layer 101, current extending 100, upper limiting layer 300, active area 200, lower limit layer 400, resilient coating 500, substrate 600, bottom electrode 20, current barrier layer 120 is positioned at the inside of upper limiting layer 300 and active area 200; Its preparation process and method are as follows:

1. on the n-type substrate 600 that GaAs etc. can form with the AlGaInP matched materials, with MOVCD method epitaxial growth buffer 500 successively, lower limit layer 400, active area 200, upper limiting layer 300, current extending 100 has so just obtained the epitaxial wafer of AlGaInP light-emitting diode;

Again by the back technology way: at first epitaxial wafer is cleaned, whirl coating also makes the zone that will do the barrier layer by lithography, this zone is consistent with top electrode 10, the way of utilizing ion to inject is injected the ion that can play barrier function at this zone upper limiting layer 300 and active area 200 the insides, form current barrier layer 120, remove photoresist and clean, then evaporation last layer ITO conduction light transmissive material;

3. next, with the evaporation way at ITO surface evaporation layer of Au ZnAu metal level, and make top electrode 10 by lithography, electrode shape such as Fig. 4 or shown in Figure 5, substrate 600 is thinned to about 100 μ m, simultaneously evaporates layer of Au GeNi at this of attenuate then and form bottom electrode 20, finished the making of upper and lower electrode, the device architecture profile as shown in Figure 7, stereogram is as shown in Figure 8; Ready-made epitaxial wafer is cleaved into the tube core of 1mm * mm, and pressure welding is on base, and the preparation of LED device finishes.

Embodiment 2

The distribution of the current barrier layer light-emitting diode corresponding in the utility model with top electrode, as shown in Figure 7, wherein:

1, the shape of top electrode 10 can be other shapes such as circle, star, bar shaped, slotting finger-type in the utility model, and the pressure welding point diameter can be 100 μ m, 80 μ m or other size.

2, the material of current barrier layer 120 can be intrinsic semiconductor, non-conductive resin, the amorphous Si that undopes, insulating material such as SixNy and SixOy also can be the electric conducting materials with conductive light antireflection layer 101 conductivity type opposite;

3, active area 200 structures are p-n junction, or the p-i-n knot, or double-heterostructure, or single quantum, or multi-quantum pit structure, superlattice structure or quantum dot light emitting structure, or multiple layer hetero quantum point structure;

4, the corresponding this structure of the distribution of current barrier layer 120 and top electrode 10 in the distribution of the current barrier layer of the present utility model light-emitting diode corresponding with top electrode can be introduced in the structure of LED such as formal dress, upside-down mounting, resonant cavity.

Conductive light antireflection layer 101 used materials can be ITO (tin indium oxides) in the utility model, the material that electroconductive resin also can be other can conduct electricity, printing opacity can play anti-reflection effect again to light.

The above is a specific embodiment of the utility model only, is not in order to limiting protection range of the present utility model, and all other do not break away from various remodeling and the modification of being carried out in claims scope, all should be included in the scope of protection of the present utility model.

Claims

1, the light-emitting diode that the distribution of current barrier layer is corresponding with top electrode, include from top to bottom the top electrode of the storied length of longitudinal layer (10) successively, current extending (100), upper limiting layer (300), active area (200), lower limit layer (400), resilient coating (500), substrate (600), bottom electrode (20), also include the current barrier layer (120) of the below that is positioned at top electrode (10), it is characterized in that: between top electrode (10) and current extending (120), be provided with conductive light antireflection layer (101), and the distribution of current barrier layer is corresponding with top electrode.

2, the light-emitting diode that the distribution of current barrier layer according to claim 1 is corresponding with top electrode, it is characterized in that: described current barrier layer (120) is arranged on conductive light antireflection layer (101) or current extending (100) or upper limiting layer (300) or active area (200) the inside, or simultaneously in conductive light antireflection layer (101) and current extending (100) the inside, or simultaneously in conductive light antireflection layer (101), current extending (100) and upper limiting layer (300) the inside, or simultaneously in conductive light antireflection layer (101), current extending (100), upper limiting layer (300) and active area (200) the inside, or simultaneously in current extending (100) and upper limiting layer (300) the inside, or simultaneously in current extending (100), upper limiting layer (300) and active area (200) the inside, or simultaneously in upper limiting layer (300) and active area (200) the inside.

3, the distribution of the current barrier layer according to claim 1 and 2 light-emitting diode corresponding with top electrode, the shape of current barrier layer (120) is identical with top electrode (10) shape.

4, the distribution of the current barrier layer according to claim 1 and 2 light-emitting diode corresponding with top electrode, it is characterized in that: on conductive light antireflection layer (101) structure sheaf that light is played anti-reflection effect is set, this structure sheaf is one deck anti-reflection film (103) or handles at conductive light antireflection layer (101) upper surface or anti-reflection film (103) upper surface and to form the roughened textures layer.