CN101645474B - Photoelectric element, manufacturing method thereof, backlight module device, and lighting device - Google Patents

Abstract

The invention discloses a photoelectric element, a manufacturing method thereof, a backlight module device and an illuminating device. The photoelectric element comprises a semiconductor light-emitting laminated layer, a first semiconductor layer, an active layer and a second semiconductor layer, wherein the surface of the first semiconductor layer is provided with a plurality of recesses; a transparent conductive layer formed on the surface of the first semiconductor layer to recess and form a hole containing air; a metal reflective layer is further disposed on the transparent conductive layer to form an omni-directional reflective layer with high reflectivity. According to the invention, the light extraction efficiency of the element is increased.

Description

Photoelectric element, manufacturing method thereof, backlight module device, and lighting device

technical field

The invention relates to a photoelectric element, in particular to a light-emitting diode element with a high-efficiency reflective layer.

Background technique

Compared with traditional incandescent bulbs and cold cathode lamps, light-emitting diodes have the advantages of energy saving and longer service life, so they are widely used in various fields, such as traffic signs, backlight modules, street lighting, medical Equipment and communication storage devices and other industries.

In order to improve the light extraction efficiency of the light-emitting diode, a reflective layer is usually placed at an appropriate position of the light-emitting diode structure, such as between the substrate and the light-emitting stack, which can reduce the light absorption effect of the substrate and allow the light generated by the light-emitting layer to pass through the above-mentioned reflective layer The reflection effect increases the light output. The reflective layer mostly uses a metal material with high reflective properties, such as gold (Au) or silver (Ag), as a single reflective metal layer. The reflection ability of this kind of reflective layer depends on the size of the reflection coefficient of the material of the reflective metal layer selected, for example, gold (Au) is about 86%, and silver (Ag) is about 92%.

Another reflective layer often used in LED structures is a Distributed Bragg Reflector (DBR). A Bragg _reflector (DBR) is a structure composed of multiple _layers of materials with different refractive indices with a thickness of about a quarter of the light wavelength. structure or a multilayer structure formed by stacking semiconductor layers of different compositions formed by an epitaxial process. Its reflectivity depends on the number of layers of the multilayer structure and the matching design of the refractive index change.

In the light-emitting diode structure, an omni-directional reflector (ODR) design can also be used, which usually has a better reflection effect than ordinary metal reflectors. An omnidirectional reflective layer (ODR) is a structure formed by stacking a semiconductor layer, a low refractive index layer, and a metal layer. The thickness of the low index layer (low index layer) is a multiple of a quarter of the wavelength of light, and usually It is an insulating material, such as silicon dioxide (SiO ₂ ) or silicon nitride (Si ₃ N ₄ ), so it does not have conductive properties.

As mentioned above, it is a known and effective method to arrange a reflective layer at an appropriate position in the light emitting diode structure to increase the light extraction efficiency of the device, but how to design a reflective layer with higher reflective efficiency has become a public question. the goal that is pursued.

Contents of the invention

The present invention provides a kind of photoelectric element, it comprises a semiconductor layer, and its surface has many depressions; An intermediate layer, is formed on the surface of semiconductor layer, and these depressions form the hole that contains air (refractive index is about 1); And A reflective layer is formed on the intermediate layer to form an omnidirectional reflective layer (ODR) with high reflection efficiency; wherein the above-mentioned intermediate layer can be a transparent conductive layer or a dielectric layer.

The present invention also provides a photoelectric element, which includes a semiconductor light emitting stack, which has a first semiconductor layer, an active layer and a second semiconductor layer, and the surface of the first semiconductor layer has many depressions; a transparent conductive layer, formed on the surface of the first semiconductor layer, and form these depressions into holes containing air (refractive index about 1); a metal reflective layer, formed on the transparent conductive layer, so as to form a high reflective efficiency Omni Directional Reflective Layer (ODR).

The present invention mainly hopes to achieve the effect of reducing the refractive index of the transparent conductive layer through the above-mentioned hole design formed between the semiconductor layer and the transparent conductive layer, so as to improve the reflection efficiency of the omnidirectional reflective layer (ODR), so that by The light generated by the active layer can be emitted through the reflection effect of the omnidirectional reflective layer (ODR), so as to increase the light extraction efficiency of the element.

Description of drawings

Fig. 1 is a first embodiment according to the present invention.

Fig. 2 is a second embodiment according to the present invention.

Fig. 3 is a third embodiment according to the present invention.

FIG. 4 is a structural diagram of a backlight module according to the present invention.

Fig. 5 is a structural diagram of an illuminating device according to the present invention.

Explanation of reference signs

200 substrate 210 first semiconductor layer

220 active layer 230 second semiconductor layer

231 holes 232 depressions

240 transparent conductive layer 250 metal reflective layer

270 first electrode 280 second electrode

300 substrate 310 connection layer

320 metal reflective layer 330 transparent conductive layer

340 first semiconductor layer 341 holes

342 concave 350 active layer

360 second semiconductor layer 370 first electrode

380 second electrode

600 backlight module device 610 light source device

611 Light-emitting element 620 Optical device

630 power supply system 700 lighting device

710 light source device 711 light emitting element

720 Power Supply System 730 Control Elements

Detailed ways

Fig. 1 is the first embodiment of the present invention. As shown in the figure, a light-emitting element, such as a light-emitting diode structure, is epitaxially formed on a substrate 200 with a first semiconductor layer 210, and then an active layer 220 is formed on the first semiconductor layer 210, and finally a first semiconductor layer 210 is formed. The second semiconductor layer 230 is on the active layer 220 , wherein the electrical properties of the first semiconductor layer 210 and the second semiconductor layer 230 are different. Then, a plurality of depressions 232 are formed on the surface of the second semiconductor layer 230, and a transparent conductive layer 240 is covered thereon. At this time, the transparent conductive layer 240 will not fill the depressions 232, thus forming a plurality of holes 231, This roughly includes air (with a refractive index of about 1). Then, on the top of the transparent conductive layer 240, a metal reflective layer 250 is formed. At this time, the second semiconductor layer 230, the transparent conductive layer 240 and the metal reflective layer 250 form an omni-directional reflective layer (omni-direction) with high reflection efficiency. reflector: ODR). Finally, a first electrode 270 and a second electrode 280 are respectively formed on the first semiconductor layer 210 and the metal reflective layer 250 to complete the structure of the light emitting diode of this embodiment.

The size of the above-mentioned plurality of holes 231 is based on the principle that the transparent conductive layer above it cannot be filled into the holes 231, and its maximum diameter is preferably about less than 200 nm, so that it generally includes air (the refractive index is about 1); its shape does not have Constraints can be hexagonal holes, inverted pyramids, irregular polygons, etc.; the arrangement is not limited, such as periodic arrangement or irregular arrangement. The formation method of the recess 230 is not limited, for example as follows: (a) epitaxial method - in the epitaxial process of forming the second semiconductor layer 230, by controlling the epitaxial conditions, the surface of the second semiconductor layer 230 naturally forms a plurality of Recess 232; (b) wet etching method--after the second semiconductor layer 230 is completed, according to the material of the second semiconductor layer 230, select an appropriate etching solution such as hydrochloric acid or phosphoric acid, and perform nanophotometry on the surface of the second semiconductor layer 230 Engraving and etching to form depressions 232; (C) nano-imprint method (nano-imprint)-after completing the second semiconductor layer 230, perform nano-imprinting process steps on its surface to form multiple depressions 232 with nanoscale; ( d) Nanosphere dispersion method--after the second semiconductor layer 230 is completed, nanospheres such as SiO ₂ , Al ₂ O ₃ , TiO ² , MgO, ZnO, etc. are spread on its surface, and then the surface of the second semiconductor layer 230 can be Form a plurality of depressions 232; (e) superalloy ball method--form a thin metal layer on the surface of the second semiconductor layer 230 first, and then use the superalloy method to convert this thin metal layer into a metal sphere, which can be A plurality of depressions 232 are formed on the surface of the second semiconductor layer 230; (f) mechanical roughening method-on the surface of the second semiconductor layer 230, a plurality of depressions 232 are formed on the surface of the second semiconductor layer 230 by mechanical grinding; (g) dry etching method---on the surface of the second semiconductor layer 230, use a dry etching method such as plasma etching, electron beam etching or laser etching, etc., to etch the surface of the second semiconductor layer 230 , forming a plurality of depressions 232 . The purpose of forming these depressions 232 is to form a structure of holes 231 containing air (refractive index is about 1) between the semiconductor layer 230 and the transparent conductive layer 240. The effect of the refractive index, thereby improving the reflective ability of the omnidirectional reflective layer (ODR).

In the above embodiment, the substrate 200 can be at least one material in the group consisting of Al ₂ O ₃ , GaN, AlN, SiC, GaAs, GaP, Si, ZnO, MgO, MgAl ₂ O ₄ and glass, or other alternative materials. materials; the first semiconductor layer 210, the active layer 220 and the second semiconductor layer 230 can be selected from materials such as GaN, AlGaN, InGaN, AlGaInP and AlInGaN; the first electrode 270 and a second electrode 280 are selected from At least one material in the group consisting of Al, Ti, Ti/Al, Cr/Al, Ti/Au, Cr/Au, Ni/Au, TiW, TiN, WSi, Au/Ge, Pt, Pd and Rb; The transparent conductive layer 240 is at least one material selected from the material group consisting of indium tin oxide, cadmium tin oxide, antimony tin oxide, zinc aluminum oxide and zinc tin oxide; the metal reflective layer 250 is a conductive material with high reflectivity. materials such as aluminum (Al) or silver (Ag).

As shown in Figure 2 is the second embodiment of the present invention. The difference between the structure of this embodiment and the first embodiment is that the omnidirectional reflective layer (ODR) formed by the first semiconductor layer 210, the transparent conductive layer 240 and the metal reflective layer 250 is located between the substrate 200 and the active layer 220. In between, the downwardly emitted light generated by the active layer 220 is reflected through the omnidirectional reflective layer (ODR) to avoid being absorbed by the underlying substrate, thereby improving the light extraction efficiency. Wherein the transparent conductive layer 240 is not only made of transparent conductive materials such as indium tin oxide, cadmium tin oxide, antimony tin oxide, zinc aluminum oxide and zinc tin oxide; it can also be replaced by a dielectric layer, which can be Inorganic dielectric materials, such as silicon dioxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), silicon nitride (SiNx), or spin-on glass, etc., or organic dielectric materials, such as Epoxy resin (epoxy), polyimide (polyimide) or BCB resin (benzocyclobutene), etc.

As shown in Figure 3 is the third embodiment of the present invention. This embodiment is a light-emitting diode structure formed by using a substrate transfer method, which has a conductive substrate 300; a first electrode 370 is arranged below it; The metal reflective layer 320 above; the transparent conductive layer 330 above the metal reflective layer 320; and the epitaxial stack above the transparent conductive layer 330, including a first semiconductor layer 340, and an active layer is formed on the first semiconductor layer 340 350, and a second semiconductor layer 360 is formed on the active layer 350, wherein the electrical properties of the first semiconductor layer 340 and the second semiconductor layer 360 are different; finally, a second semiconductor layer 360 is formed above the second semiconductor layer 360 electrode 380 . Wherein at the interface where the first semiconductor layer 340 is in contact with the transparent conductive layer 330, a plurality of depressions 342 are formed on the surface of the first semiconductor layer 340, and the transparent conductive layer 330 does not fill the depressions 342, but forms a plurality of holes 341, which roughly includes air (refractive index is about 1), wherein the forming method, size, shape, and arrangement of the holes 341 in this embodiment are the same as those in the previous embodiment. The omni-directional reflector (omni-direction reflector: ODR) formed by the first semiconductor layer 340, the transparent conductive layer 330 and the metal reflective layer 320 has high reflection efficiency, which can make the light generated by the light-emitting stack downward When emitting, the light is reflected through the reflection effect of the omnidirectional reflective layer (ODR), so as to prevent the light from being absorbed by the substrate below, thereby improving the light extraction efficiency.

In this embodiment, the substrate 300 is a substrate with conductive properties, such as at least one material in the material group composed of a silicon substrate, a copper substrate, and SiC or other replaceable materials; the first semiconductor layer 340, the active layer 350 and the second semiconductor layer 360 can be selected from a material group consisting of GaN, AlGaN, InGaN, AlGaInP and AlInGaN; the first electrode 370 and a second electrode 380 can be selected from Al, Ti, Ti/Al , Cr/Al, Ti/Au, Cr/Au, Ni/Au, TiW, TiN, WSi, Au/Ge, Pt, Pd and Rb constitute at least one material in the material group; the transparent conductive layer 330 is selected from At least one material in the material group consisting of indium tin oxide, cadmium tin oxide, antimony tin oxide, zinc aluminum oxide and zinc tin oxide; the metal reflective layer 320 is a conductive material with high reflectivity, such as aluminum (Al ) or silver (Ag); the adhesive layer 310 is at least one material selected from the material group consisting of epoxy resin (epoxy), polyimide (polyimide) or BCB resin (benzocyclobutene).

All the above-mentioned embodiments are not limited to light-emitting diode elements, and the omnidirectional reflective layer (ODR) with hole structure design can be applied to any suitable position of any photoelectric element that needs a reflective layer, such as a solar cell (Solar Cell) Or laser diode (Laser Diode), etc.

FIG. 4 shows the structure of the backlight module of the present invention. Wherein the backlight module device 600 includes: a light source device 610 composed of the light-emitting element 611 of any of the above-mentioned embodiments of the present invention; an optical device 620 placed on the light output path of the light source device 610, which emits light after proper processing; and a power supply The supply system 630 provides the power required by the above-mentioned light source device 610 .

Fig. 5 shows the structure of the lighting device of the present invention. The aforementioned illuminating device 700 may be a vehicle lamp, a street lamp, a flashlight, a street lamp, an indicator lamp, and the like. Wherein the lighting device 700 comprises: a light source device 710, constituted by the light-emitting element 711 of any embodiment of the present invention; a power supply system 720, providing the power required by the light source device 710; and a control element 730 to control the power input to the light source device 710.

Although the invention has been described above through various embodiments, it is not intended to limit the claims of the present invention. Various modifications and changes made to the present invention do not depart from the spirit and scope of the present invention.

Claims (11)

1. photoelectric cell comprises:

The luminous lamination of semiconductor has one first semiconductor layer, an active layer and one second semiconductor layer, a surface of this one first semiconductor layer wherein, and this surface has a plurality of depressions;

One transparency conducting layer is formed on this surface of this first semiconductor layer, makes those be recessed to form a plurality of holes; And

One metallic reflector is formed on this transparency conducting layer,

Wherein, these a plurality of holes are formed between this transparency conducting layer and this first semiconductor layer.

2. photoelectric cell as claimed in claim 1, wherein the maximum gauge in this hole is less than 200nm.

3. photoelectric cell as claimed in claim 1, wherein the refraction coefficient in this hole is 1.

4. photoelectric cell as claimed in claim 1, wherein the shape in this hole can be hexagon hole, inverted pyramid shape or irregular polygon.

5. photoelectric cell as claimed in claim 1, wherein this hole can be periodic arrangement or irregular alignment.

6. photoelectric cell as claimed in claim 1, the method that wherein forms this depression can be epitaxy, wet etching, nano print method, nanometer spheroid distribution method, high temperature alloy ball method, mechanical type roughening method or dry-etching method.

7. photoelectric cell as claimed in claim 1, wherein this transparency conducting layer can be replaced by an inorganic dielectric layer or organic dielectric layer.

8. photoelectric cell manufacturing approach, its step comprises:

Formation has the luminous lamination of semiconductor of one first semiconductor layer, an active layer and one second semiconductor layer;

Form on a plurality of surfaces that are depressed in this one first semiconductor layer;

Form a transparency conducting layer on this surface of this first semiconductor layer, and make those be recessed to form a plurality of holes; And

Form a metallic reflector on this transparency conducting layer,

Wherein, these a plurality of holes are formed between this transparency conducting layer and this first semiconductor layer.

9. photoelectric cell manufacturing approach as claimed in claim 8, the method that wherein forms these a plurality of depressions are epitaxy, wet etching, nano print method, nanometer spheroid distribution method, high temperature alloy ball method, mechanical type roughening method or dry-etching method.

10. back light module device comprises:

One light supply apparatus, one of them institute forms by the described photoelectric cell of claim 1～9;

One Optical devices place the going out on the light path of this light supply apparatus; And

One power system provides this light supply apparatus required power supply.

11. a lighting device comprises:

One light supply apparatus, one of them institute forms by the described photoelectric cell of claim 1～9;

One power system provides this light supply apparatus required power supply; And

One control element is controlled this this light supply apparatus of power supply input.

Images