TW575970B - High brightness light emitting diode and its manufacturing method - Google Patents

Abstract

The present invention is related to high brightness light emitting diode and its manufacturing method. The invented light emitting diode (LED) includes a gallium phosphide light window and a mirror reflection layer capable of greatly increasing the brightness. The invented LED manufacturing method particularly includes the followings: bonding a completed LED structure and the processed epitaxial layer on a glass substrate; temporarily removing the substrate for epitaxy; depositing the mirror reflection layer; bonding a permanent substrate on the mirror reflection layer bottom portion; and removing the glass substrate. Through the two bonding-procedures, the mirror reflection coefficient can be maintained, and thick window layer can be maintained on the light emission face. In addition, a substrate with excellent heat dissipation property can be provided such that it is capable of manufacturing an LED with high efficiency and high power through a simple and quick manufacturing process.

Description

575970 V. Description of the invention (1) [Technical Field] The present invention relates to a light-emitting diode and a method for manufacturing the same, especially a method using Θ gallium as an optical window; at the same time, the ohmic contact electrode is completed by heat treatment. A specular reflection layer is set in the mine to prevent the specular reflection layer from being damaged by high temperature, so as to maintain the reflectance of the four surfaces; and a light emitting diode completed by a secondary bonding process and a manufacturing method thereof. [Previous technology] According to the current development trend of visible light emitting diodes, how to increase its brightness. Among them, gallium phosphide (GaP) material has high light transmittance in the vicinity of the red to green light wavelengths, and has good conductivity, so it is often used to improve the brightness of light emitting diodes. A conventional light-emitting diode structure is shown in FIG. 8. A silicon dioxide layer 82, a metal reflective layer 83, a gallium-filled layer 84, an active light-emitting layer 85, and a gallium arsenide are sequentially formed on a silicon substrate 8 丨. (GaAs) light window 86, two electrodes 87, 88 are formed on the light window 86 of Shishenhua chain and the back of Shi Xiji 81. Among them, the gallium phosphide layer µ has the above advantages and should be a good light window material. However, the conventional light emitting diode structure cannot fully utilize the advantages of the gallium phosphide material. U.S. Patent No. 5,869,849 proposes another light emitting diode structure and manufacturing method. The gallium arsenide substrate was first used as an epitaxial temporary substrate. On the gallium arsenide substrate, an organic metal chemical vapor phase epitaxy (MO VPE) was used to form a light-emitting diode made of aluminum gallium indium (A1GaInP). Bulk structure layer, gallium phosphide layer (about 60mm) is epitaxially grown on active hair

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5. Description of the invention (2) On the light layer. The temporary substrate is etched and removed after each layer is completed, and then this crystal structure is attached to a gallium phosphide substrate by wafer bonding technology. The two electrodes are respectively on the bottom of the gallium phosphide substrate and the gallium phosphide epitaxial layer. Although this structure uses gallium phosphide as the light window, it can take advantage of the gallium phosphide material. However, the direct alignment of the lattice alignment with the high-temperature wafer is required, which limits the light emission; ^ pole = yield, resulting in higher manufacturing costs. We pretended that in view of this, the inventor has in-depth research on the problems faced by the above-mentioned light-emitting diodes through years of research and development experience in related fields, and actively seeks solutions by Fang Ning. After long-term efforts, Development and trial work, and finally found a high-brightness light-emitting diode and its manufacturing method to improve the luminous efficiency. > [Content] The main object of the present invention is to provide a high-brightness light-emitting diode and a manufacturing method thereof, which can use gallium phosphide as an optical window and avoid damage to the specular reflection layer at high temperature to improve the light-emitting diode. brightness. Another object of the present invention is to provide a high-brightness light-emitting diode and a manufacturing method thereof, which can be completed at a low temperature and is suitable for a large-area light-emitting diode. A method for manufacturing a high-brightness light-emitting diode according to the present invention, comprising the following steps: a) providing a temporary > substrate for epitaxy; b) sequentially epitaxial n-type coating on the temporary substrate for epitaxy And active light emitting layer and p-type cladding layer of quantum well structure; C) forming a p-type gallium phosphide (p-Gap) layer on the p-type cladding layer; d) on the p-type gallium phosphide Forming a metal contact layer on the (p-GaP) layer;

Page 6 575970 V. Description of the invention (3) e) The metal contact layer, p-type-gallium (p- (jap) layer, p-type coating layer, active light-emitting layer and part of the n-type f coating layer) One side is etched away to expose the n-type cladding layer; f) a p-type ohmic contact electrode and an n-type ohmic contact electrode are formed on the metal contact layer and the exposed ^ -type cladding layer, respectively, to complete the light emitting diode The main structure of the body; g) one of the main structure of this light-emitting diode forming a P-type ohmic contact electrode and an n-type ohmic contact electrode is attached to a glass substrate; h) a temporary substrate for removing the epitaxial ^ Forming a specular reflection layer on the bottom surface of the n-type coating layer; j) bonding a permanent substrate to the bottom of the specular reflection layer; and removing the glass substrate. The temporary substrate for the worm crystal of the present invention is not particularly limited, such as a gallium arsenide (GaAs) substrate. The epitaxial method of step b) is also not particularly limited, and the present invention preferably uses MOVPE. The active light emitting layer of the present invention may be a light emitting material of Groups 3 to 5 or Group 2 to 6 such as aluminum gallium indium phosphide (A1GaInP), gallium nitride (GaN) or zinc selenide (ZnSe) series of light emitting materials. The above glass substrate may be attached to the main structure of the light emitting diode by epoxy resin or wax. After the glass substrate is attached, the temporary substrate for epitaxy can be removed by etching or chemical mechanical polishing (CMp). The above-mentioned bismuth surface reflection layer is preferably formed by a coating method; it contains indium metal, gold, surface, platinum, zinc, silver, copper, nickel, gold is zinc, beryllium, gold germanium, gold germanium nickel, or a substance Combination, can also be composed of high-dielectric / low-dielectric material or dielectric material / metal material. An adhesive layer may be included between the permanent substrate and the specular reflection layer, for example, the melting point is less than 350. (: Pure metal or alloy metal, or low temperature connection

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Combined heat dissipation organic adhesive. The permanent substrate of the present invention can be a silicon substrate or a substrate with better heat dissipation effect. < Only a transparent conductive film, such as indium tin oxide (IT0), can be used between the above metal contact layer and the P-type ohmic contact electrode. It can also be transparent and conductive = it is a p-type contact electrode, and it is made into a full-surface electrode contact. The high-brightness light-emitting diode of the present invention mainly includes: a permanent substrate; a specular reflection layer is formed on the permanent substrate; an n-type cladding layer is formed on the specular reflection layer, and one side surface thereof is Part removed by etching; 7 an active light emitting layer having a quantum well structure and formed on an unetched surface of the n-type coating layer; a p-type coating layer formed on the active light-emitting layer; a p-type phosphorus A gallium (p-GaP) layer is formed on the p-type cladding layer; a metal contact layer is formed on the p-type gallium phosphide layer; a p-type ohmic contact electrode is formed on the metal contact layer; and an η A type ohmic contact electrode is formed on the n-type cladding layer to be etched away. The material of the light-emitting diode of the present invention can be as described above. The metal contact layer and the P-type ohmic contact electrode may further include a transparent conductive plutonium, such as indium tin oxide (ITO). A transparent conductive film can also be used as the p-type ohmic contact electrode, and the entire surface can be made into electrode contact. [Embodiment] The following describes the preferred embodiment of the present invention in conjunction with the drawings for further explanation, which can enable your review committee to have a more detailed understanding of the present invention. However, what is described below is only used to explain the preferred embodiments of the present invention, and is not based on it.

Page 8 575970 V. Description of the invention (5) Any form of limitation is imposed on the invention. Therefore, any form of modification or change based on the spirit of the invention of the invention should belong to the scope of the invention. First, as shown in FIG. 1, a MoVpE method is used to grow an epitaxial LED layer with a multilayer coating layer on a temporary substrate 91 made of a gallium arsenide (GaAs) worm crystal. It is an n-type-aluminum-gallium-indium phosphide (n_type A1GaInp) epitaxial layer, and the second coating layer 13 is a p-type-aluminum-gallium-indium-phosphorus (p_type A1GaInP) worm-crystal layer. An active light emitting layer 12 is formed on the crystal layer 丨 丨. The active light-emitting layer 12 has a ρη interface, which can be a direct-bandgap Group II or VI compound or a Group III-V compound, such as an undoped filled indium gallium indium (AlGalnP). It is 550 to 630 nm. The above aluminum gallium indium phosphide can be expressed as (AlxGal-χ) 0.51η0.5. For the first coating layer 11 and the second coating layer 13, 0.5 $ χ $ 1; in the case of an active light emitting layer In terms of 12, 〇 $ χ $ 〇β45. A transparent p-type-gallium phosphide (p-GaP) epitaxial layer 21 is formed on the second cladding layer 13 with a thickness of about 0.2 to 60 // m. The band gap of the epitaxial layer 21 of the gallium phosphide layer is also higher than that of the LED epitaxial layer. It has high light transmittance in the wavelength range from red to green, and has much better conductivity than aluminum gallium indium phosphide. Avoid current crowding effect. The gallium-filled system increases the luminous efficiency by increasing the light emitted in parallel and reducing the light absorbed by the substrate. Therefore, the thickness of the filled gallium epitaxial layer 271 should be at least 0.6 times that of the light emitting diode 'and can be formed using a gas phase stupid method. The use of fillers as light window materials can increase the brightness by about two to three times. After that, a metal contact layer 22 is formed on the scaled gallium epitaxial layer 21, and

Page 9 575970 V. Description of the invention (6) One of the metal contact layer 22, p-type-nitrate: graft layer 21, p-type coating layer 13, active light-emitting layer 12 and part of n-type coating layer 1 1 The side etching is removed to expose the n-type cladding layer 11. '' In order to improve the conductivity of the surface of the light-emitting diode, a metal contact layer 22 of GaAs material is grown on the filled residual insect layer 21, and then a layer of indium tin oxide (IT0) material is sputtered. The transparent conductive film 33. Next, as shown in FIG. 2, a p-type ohmic contact electrode 31 and an n-type ohmic contact electrode 3 2 are plated on the metal contact layer 22 and the exposed cover layer 11 respectively, and the light-emitting diode of the present invention is completed. The main structure. In addition, the present invention may further include a transparent conductive film 33 between the metal contact layer 22 and the p-type ohmic contact electrode 31. Alternatively, the transparent conductive film 33 of this embodiment can also be used as a p-type ohmic contact electrode. Next, "the main structure of the light-emitting diode is formed by attaching one surface of the P-type ohmic contact electrode 31 and the n-type ohmic contact electrode M to a supporting glass substrate 92" as shown in FIG. The glass substrate 92 needs to be coated with a layer of 躐 93 'at 70 to 80 ° C to make the 躐 93 adhesive. By using the glass substrate 92 as the stupid crystal layer, the temporary substrate 91 of the gallium epitaxial crystal that absorbs part of the light wavelength can be removed by the button-cut method, as shown in FIG. 4. In order to improve the brightness of the light-emitting diode, a specular reflection layer 25 is coated on the bottom of the LED epitaxial layer, so that the light emitted by the active light-emitting layer 12 can be emitted from the front side, as shown in FIG. 5. The material of the specular reflection layer 25 may be a substance containing indium, tin, lu, gold, platinum, platinum, zinc, silver, germanium, nickel, gold zinc, gold beryllium, gold germanium, gold germanium nickel, or a combination thereof. Reflective layer with negative composition of electric / low dielectric material, mirror made of dielectric material / metal material

Page 10 575970 V. Description of the invention (7) Surface reflection layer. Next, as shown in FIG. 6, an adhesive layer 41 such as a low-temperature metal adhesive layer or a heat-dissipating adhesive layer such as silver glue is mined on the permanent substrate 42 with good heat dissipation properties, and then bonded to specular reflection. At the bottom of the layer 25, the permanent substrate 42 used in this embodiment is a silicon substrate. Under the support of the permanent substrate 42, the glass substrate 92 is no longer necessary, and it can be removed to make the gallium phosphide epitaxial layer 21 the main light window. Thus, the high-brightness light-emitting diode 2 of the present invention shown in FIG. 7 is completed. Production of polar bodies. Since the light emitting diode of the present invention includes a gallium phosphide light window and a specular reflection layer, the brightness can be greatly improved. In addition, the method for manufacturing a light-emitting diode of the present invention particularly includes attaching a glass substrate to a P-type ohmic contact electrode, and attaching a permanent substrate to the bottom of the specular reflection layer, whereby The secondary attachment process makes the manufacturing process easier and faster. In addition, the heat treatment element is used to form an ohmic contact electrode, and then a specular reflective layer is plated to prevent the specular reflective layer from being damaged by high temperature and maintain the specular reflectivity. The manufacturing method of the present invention can be completed at a low temperature to 'make the manufacturing process easier and faster' and is applicable to a large-area hair-emitting diode. To sum up, the invention works in full compliance with the 19th Law of the Patent Law. Schematic description is a highly innovative article using the laws of nature and the provisions of Article 20, so reliance on

Page 11 575970 V. Description of the invention (8) Figures 1 to 7 show the manufacturing process of the embodiment of the present invention. FIG. 8 shows a conventional light-emitting diode structure.

The drawing number illustrates the first coating layer 11 the active light-emitting layer 1 2 the second other coating layer 13 the scaled grafted stupid crystal layer 2 1 the metal contact layer 2 2 the specular reflection layer 2 5 the p-type ohmic contact electrode 31 the n-type ohmic contact electrode 32 Transparent conductive film 3 3 Adhesive layer 41 Permanent substrate 4 2 Shi Xi substrate 8 1 Silicon dioxide layer 8 2 Metal reflective layer 83 Gallium phosphide layer 8 4 Active light emitting layer 8 5 GaAs light window 8 6 Electrode 87, 88 Crystal temporary substrate 9 1 glass substrate 92 wax 93

Page 12 575970 Brief Description of Drawings Figures 1 to 7 show the manufacturing process of the embodiment of the present invention. FIG. 8 shows a conventional light-emitting diode structure. liimi p. 13

Claims (1)

Private year M h correction 575970 VI. Application Patent Scope I A method for manufacturing a high-brightness light-emitting diode, including the following steps: a) providing a temporary substrate for epitaxy; 'b) sequentially epitaxial on the temporary substrate for epitaxy η Pear cladding layer, active light emitting layer of quantum well structure and P-type cladding layer; C) forming a P-type-gallium phosphide (P-Gap) layer on the P-type cladding layer; d) a metal contact layer is formed on the p-type gallium phosphide (ρ-'P) layer; e) the metal contact layer, the p-type gallium (p-GaP) layer, the p-type cladding layer, and active light emission Layer and part of the η-type cladding layer are etched to remove neodymium to expose the η-type cladding layer; t ί) ρ-type ohmic contact electrodes and η are formed on the metal contact layer and the exposed η-type cladding layer, respectively -Type ohmic contact electrode to complete the main structure of the light-emitting diode; S) forming one of the p-type ohmic contact electrode and the n-type ohmic contact electrode in the main structure of the light-emitting diode; — Glass substrate; & h) a temporary substrate for removing the epitaxial wafer; i) forming a specular reflection layer on the bottom surface of the n-type cladding layer J) bonding a permanent substrate to the bottom of the specular reflection layer; and k) removing the glass substrate. 2. The method according to item 1 of the scope of patent application, wherein the temporary substrate used for the epitaxy is a GaAs substrate. 3. The method according to item 1 of the scope of patent application, wherein step b) is performed by a metal oxide vapor phase epitaxy method (MOVPE). 4. The method according to item 1 of the scope of patent application, wherein the active light emitting layer Page 14 575970 VI. Scope of patent application _____ 一 ^-"一 ^" is aluminum gallium indium phosphide (AlGalnP). 5. The method as described in item 1 of the scope of the patent application, wherein the glass substrate is attached to the main structure of the urethane body with a soil oxygen resin (e ρ ο X y). 6. The method according to item 1 of the scope of patent application, wherein the glass substrate is attached to the main structure of the light emitting diode with wax. 7 The method as described in item 1 of the scope of patent application, wherein the temporary i-plate is removed with the last name carved. 8. The method according to item 1 of the scope of patent application, wherein the temporary substrate is removed by a chemical mechanical polishing (CMP) method. 9. The method according to item 1 of the scope of patent application, wherein the specular reflection layer is formed by coating. I. The method as described in item 1 of the scope of patent application, wherein the mirror reflective layer is selected from the group consisting of indium, tin, aluminum, gold, platinum, platinum, zinc, silver, germanium, nickel, gold zinc, and gold wrinkles. , Gold fault, gold germanium nickel, or a combination thereof. II. The method according to item 1 of the patent application, wherein the specular reflection layer is composed of a high-dielectric / low-dielectric material. 1 2 · The method according to item 1 of the scope of patent application, wherein the specular reflection layer is made of a dielectric material / metal material. 1 3 · The method as described in item 1 of the scope of patent application, wherein the permanent substrate is attached to the bottom surface of the specular reflection layer by an adhesive layer below 350 ° C. 14. The method according to item 13 of the scope of patent application, wherein the adhesive layer is a pure metal having a melting point of less than 350 ° C. 15 · The method as described in item 13 of the scope of patent application, wherein the adhesive layer is an alloy metal having a melting point of less than 350 ° C. Page 575970 6. Scope of patent application L___ 1 6 · The method as described in the scope of patent application No. 3 $, wherein the heat dissipation of the bonding at low temperature is organically followed. … ._____— 1 7 · The method according to item 1 of the scope of patent application, wherein the permanent substrate is a silicon substrate. ‘18. The method according to item 1 of the scope of patent application, wherein the permanent substrate is a metal substrate. ′ 1 9 The method according to item 1 of the scope of patent application, wherein a transparent conductive film is further included between the metal-contact layer and the P-type ohmic contact electrode. The method described in item 1 of the scope of patent application, wherein the P-type: Sum contact electrode is a transparent conductive film. 21 · —A kind of high-brightness light-emitting diode, comprising: a permanent substrate; a specular reflection layer is formed on the permanent substrate; an n-type coating layer is formed on the specular reflection layer, and one side surface is etched Removed part; an active light-emitting layer having a quantum well structure and formed on the unetched surface of the n-type cladding layer; a P-type cladding layer formed on the active light-emitting layer; a P-type gallium phosphide (P-GaP) layer is formed on the P-type cladding layer; a metal contact layer is formed on the gallium phosphide layer; a P-type ohmic contact electrode is formed on the metal contact layer; and an n-type ohmic contact electrode It is formed on the etched surface of the n-type cladding layer. 2 2 · The high-brightness light-emitting diode described in item 21 of the scope of patent application, which Page 16 575970 Knee A! Year of February / February-Supplement 丨 Sixth, the scope of patent application ', in which the permanent substrate is a silicon substrate. > 2 3 · As described in the scope of the patent application No. 21 <. High-brightness light-emitting diode f, wherein the permanent substrate is a metal substrate ~ ^ 24 · The high-brightness light-emitting diode described in the 21st patent scope A body, wherein the permanent substrate and the mirror-coated layer further include an adhesive layer. 25. The high-brightness light-emitting diode as described in item 24 of the patent application scope 3, wherein the adhesive layer is a pure metal having a melting point of less than 350. 2 6 · The south exempt light-emitting diode according to item 24 of the scope of patent application, wherein the adhesive layer is an alloy metal with a melting point of less than 350. 27. The high-brightness light-emitting diode according to item 24 of the scope of the patent application, wherein the adhesive layer is a low-temperature heat-dissipating organic adhesive. 28. The high-brightness light-emitting diode according to item 21 of the scope of the patent application, wherein the specular reflection layer is selected from the group consisting of indium, tin, boat, gold, surface, platinum, zinc, silver, germanium, nickel, gold and zinc , Gold beryllium, gold germanium, gold germanium nickel, or combinations thereof. 29. The high-brightness light-emitting diode according to item 21 of the scope of the patent application, wherein the active light-emitting layer is aluminum gallium indium phosphide (A1G a I nP). 30. The high-brightness light-emitting diode according to item 21 of the scope of the patent application, wherein a transparent conductive film is further included between the metal contact layer and the p-type ohmic contact electrode. 31. The high-brightness light-emitting diode as described in item 21 of the patent application, wherein the P-type ohmic contact electrode is a transparent conductive film. "