WO2008001990A1 - Iii-nitride semiconductor light emitting device and method for manufacturing the same - Google Patents
Iii-nitride semiconductor light emitting device and method for manufacturing the same Download PDFInfo
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- WO2008001990A1 WO2008001990A1 PCT/KR2006/005756 KR2006005756W WO2008001990A1 WO 2008001990 A1 WO2008001990 A1 WO 2008001990A1 KR 2006005756 W KR2006005756 W KR 2006005756W WO 2008001990 A1 WO2008001990 A1 WO 2008001990A1
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- WIPO (PCT)
- Prior art keywords
- compound semiconductor
- nitride compound
- substrate
- semiconductor layer
- electrode
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- 239000004065 semiconductor Substances 0.000 title claims abstract description 131
- 238000000034 method Methods 0.000 title claims abstract description 54
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 19
- -1 nitride compound Chemical class 0.000 claims abstract description 102
- 239000000758 substrate Substances 0.000 claims abstract description 58
- 230000006798 recombination Effects 0.000 claims abstract description 9
- 238000005215 recombination Methods 0.000 claims abstract description 9
- 230000008569 process Effects 0.000 claims description 18
- 238000001039 wet etching Methods 0.000 claims description 12
- 238000001312 dry etching Methods 0.000 claims description 10
- 238000005530 etching Methods 0.000 claims description 6
- RHZWSUVWRRXEJF-UHFFFAOYSA-N indium tin Chemical compound [In].[Sn] RHZWSUVWRRXEJF-UHFFFAOYSA-N 0.000 claims description 4
- 229910001887 tin oxide Inorganic materials 0.000 claims description 4
- 238000005498 polishing Methods 0.000 claims description 2
- 150000001875 compounds Chemical class 0.000 abstract description 4
- 239000004020 conductor Substances 0.000 abstract 1
- 229910052782 aluminium Inorganic materials 0.000 description 4
- 230000004888 barrier function Effects 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 229910052737 gold Inorganic materials 0.000 description 3
- 229910052594 sapphire Inorganic materials 0.000 description 3
- 239000010980 sapphire Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 230000003213 activating effect Effects 0.000 description 2
- 230000004913 activation Effects 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 238000009792 diffusion process Methods 0.000 description 2
- 239000002019 doping agent Substances 0.000 description 2
- 229910052738 indium Inorganic materials 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 229910052709 silver Inorganic materials 0.000 description 2
- 229910052718 tin Inorganic materials 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- JMASRVWKEDWRBT-UHFFFAOYSA-N Gallium nitride Chemical compound [Ga]#N JMASRVWKEDWRBT-UHFFFAOYSA-N 0.000 description 1
- 238000000137 annealing Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000005229 chemical vapour deposition Methods 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 238000000206 photolithography Methods 0.000 description 1
- 229920002120 photoresistant polymer Polymers 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 238000002207 thermal evaporation Methods 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/02—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
- H01L33/20—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies with a particular shape, e.g. curved or truncated substrate
- H01L33/22—Roughened surfaces, e.g. at the interface between epitaxial layers
Definitions
- the present invention relates to a III- nitride (compound) semiconductor light emitting device and a method for manufacturing the same, and more particularly, to a Ill-nitride compound semiconductor light emitting device which can improve external quantum efficiency by forming a rough surface with a high density by using wet etching and dry etching, and a method for manufacturing the same.
- FIG. 1 is a cross-sectional view illustrating one example of a conventional Ill-nitride
- the conventional semiconductor light emitting device includes a substrate 100, a buffer layer 200 epitaxially grown on the substrate 100, an n-type nitride compound semiconductor layer 300 epitaxially grown on the buffer layer 200, an active layer 400 epitaxially grown on the n-type nitride compound semiconductor layer 300, a p-type nitride compound semiconductor layer 500 epitaxially grown on the active layer 400, a p-side electrode 600 formed on the p-type nitride compound semiconductor layer 500, a p-side bonding pad 700 formed on the p-side electrode 600, and an n-side electrode 800 formed on the n-type nitride compound semiconductor layer 301 exposed by mesa-etching at least the p-type nitride compound semiconductor layer 500 and the active layer 400.
- a GaN substrate can be used as a same kind substrate, and a sapphire substrate, an SiC substrate or an Si substrate can be used as a different kind substrate. Any kind of substrate on which the nitride compound semiconductor layer can be grown can be used. If the SiC substrate is used, the n-side electrode 800 can be formed at the side of the SiC substrate.
- the nitride compound semiconductor layers epitaxially grown on the substrate 100 are mostly grown by the metal organic chemical vapor deposition (MOCVD).
- the buffer layer 200 serves to overcome differences in lattice parameter and thermal expansion coefficient between the different kind substrate 100 and the nitride compound semiconductor.
- USP 5,122,845 discloses a method for growing an AIN buffer layer having a thickness of 100 to 500A on a sapphire substrate at 380 to 800°C.
- USP 5,290,393 suggests a method for growing an Al Ga N (0 ⁇ x ⁇ l) buffer layer o (X) (1"X) having a thickness of 10 to 5000A on a sapphire substrate at 200 to 900°C.
- Korea Patent 10-0448352 discloses a method for growing an SiC buffer layer at 600 to 990°C, and growing an In Ga N (0 ⁇ x ⁇ l) layer thereon.
- n-type nitride compound semiconductor layer 300 At least the n-side electrode 800 formed region (n-type contact layer) is doped with a dopant.
- the n-type contact layer is made of GaN and doped with Si.
- USP 5,733,796 discloses a method for doping an n-type contact layer at a target doping concentration by controlling a mixture ratio of Si and a source material.
- the active layer 400 generates light quanta (light) by recombination of electrons and holes.
- the active layer 400 is made of In Ga N (0 ⁇ x ⁇ l) and
- the p-type nitride compound semiconductor layer 500 is doped with an appropriate dopant such as Mg, and provided with p-type conductivity by activation.
- USP 5,247,533 discloses a method for activating a p-type nitride compound semiconductor layer by electron beam radiation.
- USP 5,306,662 teaches a method for activating a p- type nitride compound semiconductor layer by annealing over 400°C.
- Korea Patent 10-043346 suggests a method for endowing a p-type nitride compound semiconductor layer with p-type conductivity without activation, by using NH and a hydrogen group source material as a nitrogen precursor for the growth of the p-type nitride compound semiconductor layer.
- the p-side electrode 600 facilitates current supply to the whole p-type nitride compound semiconductor layer 500.
- USP 5,563,422 discloses a light transmitting electrode formed almost on the whole surface of a p-type nitride compound semiconductor layer to ohmic-contact the p-type nitride compound semiconductor layer, and composed of Ni and Au.
- USP 6,515,306 suggests a method for forming an n-type super lattice layer on a p-type nitride compound semiconductor layer, and forming a light transmitting electrode made of ITO thereon.
- the p-side electrode 600 can be formed thick not to transmit light, namely, to reflect light to the substrate side.
- a light emitting device using the p-side electrode 600 is called a flip chip.
- USP 6,194,743 teaches an electrode structure including an Ag layer having a thickness over 20nm, a diffusion barrier layer for covering the Ag layer, and a bonding layer made of Au and Al for covering the diffusion barrier layer.
- the p-side bonding pad 700 and the n-side electrode 800 are formed for current supply and external wire bonding.
- USP 5,563,422 suggests a method for forming an n- side electrode with Ti and Al
- USP 5,652,434 suggests a method for making a p- side bonding pad contact a p-type nitride compound semiconductor layer by removing a part of a light transmitting electrode.
- An object of the present invention is to provide a Ill-nitride (compound) semiconductor light emitting device and a method for manufacturing the same.
- Another object of the present invention is to provide a vertical structure type III- nitride compound semiconductor light emitting device, and a method for manufacturing the same.
- Yet another object of the present invention is to provide a Ill-nitride compound semiconductor light emitting device which includes a substrate with a groove formed therein, and a method of(for) manufacturing the same.
- Yet another object of the present invention is to provide a vertical structure type III- nitride compound semiconductor light emitting device which can improve external quantum efficiency, and a method of(for) manufacturing the same.
- a method of manufacturing a Ill-nitride compound semiconductor light emitting device including: a substrate; a plurality of nitride compound semiconductor layers being grown on the substrate, and having a first nitride compound semiconductor layer with first conductivity, a second nitride compound semiconductor layer with second conductivity different from the first conductivity, and an active layer interposed between the first nitride compound semiconductor layer and the second nitride compound semiconductor layer, for generating light by recombination of electrons and holes; and a rough surface formed on the plurality of nitride compound semiconductor layers, for externally emitting light generated in the active layer, the method including: a first step for forming the plurality of nitride compound semiconductor layers on the substrate; and a second step for forming the rough surface on the plurality of nitride compound semiconductor layers by wet etching and dry etching.
- the method includes a step for forming a mask on the plurality of nitride compound semiconductor layers, prior to the second step.
- the mask is formed by using a conductive oxide film.
- the conductive oxide film is made of indium tin oxide(ITO).
- a method of manufacturing a Ill-nitride compound semiconductor light emitting device including: a substrate; a plurality of nitride compound semiconductor layers being grown on the substrate, and having a first nitride compound semiconductor layer with first conductivity, a second nitride compound semiconductor layer with second conductivity different from the first conductivity, and an active layer interposed between the first nitride compound semiconductor layer and the second nitride compound semiconductor layer, for generating light by recombination of electrons and holes; and a rough surface formed on the plurality of nitride compound semiconductor layers, for externally emitting light generated in the active layer, the method including: a first step for forming the plurality of nitride compound semiconductor layers on the substrate; a second step for forming an electrode on the plurality of nitride compound semiconductor layers; a third step for wet-etching part of the electrode; and a fourth step for forming the rough surface on the
- the electrode is formed by using a conductive oxide film.
- the conductive oxide film is made of indium tin oxide(ITO).
- a method of manufacturing a Ill-nitride compound semiconductor light emitting device including: a first step for forming a groove in a substrate; a second step for forming a plurality of nitride compound semiconductor layers on the substrate with the groove formed therein; a third step for forming a first electrode on the plurality of nitride compound semiconductor layers; and a fourth step for forming a rough surface on the plurality of nitride compound semiconductor layers by etching the first electrode.
- the method includes a fifth step for forming a second electrode to be electrically connected to the plurality of nitride compound semiconductor layers through the groove.
- the method includes a step for polishing the substrate, prior to the fifth step.
- the fourth step includes a wet etching process and a dry etching process.
- a III- nitride compound semiconductor light emitting device including: a substrate with a groove formed therein; a plurality of nitride compound semiconductor layers being grown on the substrate, and having a first nitride compound semiconductor layer with first conductivity, a second nitride compound semiconductor layer with second conductivity different from the first conductivity, and an active layer interposed between the first nitride compound semiconductor layer and the second nitride compound semiconductor layer, for generating light by recombination of electrons and holes; a first electrode electrically contacting the first nitride compound semiconductor layer through the groove; a second electrode formed on the plurality of nitride compound semiconductor layers; and a protrusion formed on the periphery of the second electrode, for forming a rough surface.
- the protrusion is formed by etching at least the second nitride compound semiconductor layer.
- the protrusion is formed on the first nitride compound semiconductor layer.
- the first electrode is a reflecting film.
- the current can be uniformly diffused in the light emitting device.
- the vertical structure type light emitting device can be manufactured without separating the substrate from the plurality of Ill-nitride compound semiconductor layers.
- the external quantum efficiency of the light emitting device can be improved.
- Fig. 1 is a cross-sectional view illustrating a conventional Ill-nitride compound semiconductor light emitting device
- Fig. 2 is a cross-sectional view illustrating a substrate on which a plurality of nitride compound semiconductor layers have been grown in accordance with the present invention
- Fig. 3 is an explanatory view illustrating a manufacturing process of a Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
- FIG. 2 is a cross-sectional view illustrating a substrate on which a plurality of nitride compound semiconductor layers have been grown in accordance with the present invention.
- a buffer layer 20 is formed on a substrate 10 with grooves 80 formed therein, an n-type nitride compound semiconductor layer 30 is formed on the buffer layer 20, an active layer 40 for generating light by recombination of electron and hole is formed on the n-type nitride compound semiconductor layer 30, a p-type nitride compound semiconductor layer 50 is formed on the active layer 40, and a p-side electrode 60 is formed on the p-type nitride compound semiconductor layer 50.
- the grooves 80 are formed on the top surface of the substrate 10 by using a laser with a 355nm wavelength region. In a state where the laser is focused, the grooves 80 can be formed in various circular, elliptical or polygonal shapes with a diameter of a few to a few hundreds D. The depth of the grooves 80 can be controlled between a few D and a few hundreds D by energy of the laser, etc.. The grooves 80 can be formed to perfortrate the substrate 10.
- the buffer layer 20 formed on the substrate 10 with the grooves 80 formed therein serves to overcome differences in lattice constant and thermal expansion coefficient between the substrate 10 and the nitride compound semiconductor layer. Since the buffer layer 20 is a very thin layer with a thickness of a few tens to a few hundreds A, the buffer layer 20 is not grown in the lateral direction in the groove formed regions.
- the n-type nitride compound semiconductor layer 30 grown on the buffer layer 20 is grown in the lateral direction by controlling the growth conditions. During the lateral growth, the n-type nitride compound semiconductor layer 30 is grown to fill the groove formed regions. Meanwhile, openings may be formed on the grooves 80 according to the growth conditions.
- the p-side electrode 60 formed on the p-type nitride compound semiconductor layer 50 is made of a conductive oxide film (for example, ITO) which can make light transmit so as to emit light generated in the active layer 40.
- the conductive oxide film contains at least one selected from the group consisting of Zn, In, Sn, Ni, Ga, Cu, La, Ag and Al.
- FIG. 3 is an explanatory view illustrating a manufacturing process of a Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
- a rough surface 70 is formed in the region except a light emitting portion 90.
- the region excluding the light emitting portion 90 serves as a margin space for cutting in the manufacturing process of the chip. Normally, the margin space for cutting has a size of 20 to 6OD between the devices.
- a photoresist 7 is deposited on the light emitting portion 90 by using a photolithography process.
- a wet etching process is carried out thereon by using a solution containing HCl. It is obvious that the surface roughness of the region excluding the light emitting portion 90 is changed by a concentration of an etchant, a temperature and an etching time. For example, the wet etching process can be performed for 30 sec. by maintaining the temperature of the etchant at 45°C.
- a conductive oxide film 5 with a rough surface formed by the wet etching process serves as a mask in a succeeding dry etching process.
- the rough surface 70 consisting of high density protrusions can be formed by using the conductive oxide film 5 as an etch mask.
- the dry etching process is carried out by using, generally, plasma.
- a Cl group gas is used as a gas for generating plasma.
- the Cl group gas can be prepared by singly or mixedly using Cl , BCl , CCl and HCl.
- the etch conditions may include 30sccm of Cl , 1.5mTorr of process pressure, 200W of ICP source RF power, 45W of RF bias (RF) power, and 20 min. of time.
- the conductive oxide film 5 formed in the region excluding the light emitting portion 90 is wholly removed by the wet etching process and the dry etching process.
- the rough surface 70 serves to increasingly externally emit light generated in the active layer.
- the rough surface 70 is formed by exposing the n-type nitride compound semiconductor layer 30.
- the rough surface 70 can be formed on the active layer 40 or the p-type nitride compound semiconductor layer 50.
- the rear surface of the substrate 10 is polished to at least the groove formed regions by grinding or wrapping, thereby exposing the grooves 80.
- a final thickness of the substrate 10 ranges from 50 to 400D, preferably, 30 to 300D. If the final thickness of the substrate 10 is below 50D, the substrate 10 may be broken in a succeeding process, and if the final thickness is over 400D, the substrate 10 may not be easily cut by a succeeding scribing process, and the vertical structure type light emitting device may not be much improved in brightness and thermal characteristic.
- an n-side electrode 81 is formed through the exposed grooves 80.
- the n-side electrode 81 can be formed by sputtering, E-beam evaporation or thermal deposition.
- the n-side electrode 81 contains any one selected from the group consisting of Ni, Au, Ag, Cr, Ti, Pt, Pd, Rh, Ir, Al, Sn, In, Ta, Cu, Co, Fe, Ru, Zr, W and Mo, or a combination thereof.
- the n-side electrode 81 formed on the substrate 10 serves as an n-side bonding pad to apply the current to the semiconductor light emitting device. Meanwhile, the n-side electrode 81 can be formed on the whole substrate 10 to serve as a reflecting film.
- the above process is nothing but an example of the present invention. That is, it must be recognized that the present invention includes slight change of an epitaxial structure, addition/reduction of a supplementary epitaxial layer, and addition/omission of a supplementary process.
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Abstract
The present invention discloses a Ill-nitride (compound) semiconductor light emitting device and a method for manufacturing the same. The Ill-nitride compound semiconductor light emitting device includes a substrate with a groove formed therein, a plurality of nitride compound semiconductor layers being grown on the substrate, and having a first nitride compound semiconductor layer with first conductivity, a second nitride compound semi¬ conductor layer with second conductivity different from the first conductivity, and an active layer interposed between the first nitride compound semiconductor layer and the second nitride compound semiconductor layer, for generating light by recombination, a first electrode electrically contacting the first nitride compound semiconductor layer through the groove, a second electrode formed on the plurality of nitride compound semiconductor layers, and a protrusion formed on the periphery of the second electrode, for forming a rough surface.
Description
Description
III-NITRIDE SEMICONDUCTOR LIGHT EMITTING DEVICE AND METHOD FOR MANUFACTURING THE SAME
Technical Field
[1] The present invention relates to a III- nitride (compound) semiconductor light emitting device and a method for manufacturing the same, and more particularly, to a Ill-nitride compound semiconductor light emitting device which can improve external quantum efficiency by forming a rough surface with a high density by using wet etching and dry etching, and a method for manufacturing the same.
[2]
Background Art
[3] Fig. 1 is a cross-sectional view illustrating one example of a conventional Ill-nitride
(compound) semiconductor light emitting device. The conventional semiconductor light emitting device includes a substrate 100, a buffer layer 200 epitaxially grown on the substrate 100, an n-type nitride compound semiconductor layer 300 epitaxially grown on the buffer layer 200, an active layer 400 epitaxially grown on the n-type nitride compound semiconductor layer 300, a p-type nitride compound semiconductor layer 500 epitaxially grown on the active layer 400, a p-side electrode 600 formed on the p-type nitride compound semiconductor layer 500, a p-side bonding pad 700 formed on the p-side electrode 600, and an n-side electrode 800 formed on the n-type nitride compound semiconductor layer 301 exposed by mesa-etching at least the p-type nitride compound semiconductor layer 500 and the active layer 400.
[4] In the case of the substrate 100, a GaN substrate can be used as a same kind substrate, and a sapphire substrate, an SiC substrate or an Si substrate can be used as a different kind substrate. Any kind of substrate on which the nitride compound semiconductor layer can be grown can be used. If the SiC substrate is used, the n-side electrode 800 can be formed at the side of the SiC substrate.
[5] The nitride compound semiconductor layers epitaxially grown on the substrate 100 are mostly grown by the metal organic chemical vapor deposition (MOCVD).
[6] The buffer layer 200 serves to overcome differences in lattice parameter and thermal expansion coefficient between the different kind substrate 100 and the nitride compound semiconductor. USP 5,122,845 discloses a method for growing an AIN buffer layer having a thickness of 100 to 500A on a sapphire substrate at 380 to 800°C. USP 5,290,393 suggests a method for growing an Al Ga N (0<x<l) buffer layer o (X) (1"X) having a thickness of 10 to 5000A on a sapphire substrate at 200 to 900°C. Korea Patent 10-0448352 discloses a method for growing an SiC buffer layer at 600 to 990°C,
and growing an In Ga N (0<x≤l) layer thereon.
(x) (1-x)
[7] In the n-type nitride compound semiconductor layer 300, at least the n-side electrode 800 formed region (n-type contact layer) is doped with a dopant. Preferably, the n-type contact layer is made of GaN and doped with Si. USP 5,733,796 discloses a method for doping an n-type contact layer at a target doping concentration by controlling a mixture ratio of Si and a source material.
[8] The active layer 400 generates light quanta (light) by recombination of electrons and holes. Normally, the active layer 400 is made of In Ga N (0<x≤l) and
(x) (1-χ) comprised of single or multi well layers. WO02/021121 suggests a method for partially doping a plurality of quantum well layers and barrier layers.
[9] The p-type nitride compound semiconductor layer 500 is doped with an appropriate dopant such as Mg, and provided with p-type conductivity by activation. USP 5,247,533 discloses a method for activating a p-type nitride compound semiconductor layer by electron beam radiation. USP 5,306,662 teaches a method for activating a p- type nitride compound semiconductor layer by annealing over 400°C. Also, Korea Patent 10-043346 suggests a method for endowing a p-type nitride compound semiconductor layer with p-type conductivity without activation, by using NH and a hydrogen group source material as a nitrogen precursor for the growth of the p-type nitride compound semiconductor layer.
[10] The p-side electrode 600 facilitates current supply to the whole p-type nitride compound semiconductor layer 500. USP 5,563,422 discloses a light transmitting electrode formed almost on the whole surface of a p-type nitride compound semiconductor layer to ohmic-contact the p-type nitride compound semiconductor layer, and composed of Ni and Au. USP 6,515,306 suggests a method for forming an n-type super lattice layer on a p-type nitride compound semiconductor layer, and forming a light transmitting electrode made of ITO thereon.
[11] Meanwhile, the p-side electrode 600 can be formed thick not to transmit light, namely, to reflect light to the substrate side. A light emitting device using the p-side electrode 600 is called a flip chip. USP 6,194,743 teaches an electrode structure including an Ag layer having a thickness over 20nm, a diffusion barrier layer for covering the Ag layer, and a bonding layer made of Au and Al for covering the diffusion barrier layer.
[12] The p-side bonding pad 700 and the n-side electrode 800 are formed for current supply and external wire bonding. USP 5,563,422 suggests a method for forming an n- side electrode with Ti and Al, and USP 5,652,434 suggests a method for making a p- side bonding pad contact a p-type nitride compound semiconductor layer by removing a part of a light transmitting electrode.
[13] On the other hand, a vertical structure type light emitting device in which electrodes
are positioned at upper and lower portions of a plurality of nitride compound semiconductor layers has been recently suggested. [14]
Disclosure of Invention
Technical Problem
[15] The present invention is achieved to solve the above problems. An object of the present invention is to provide a Ill-nitride (compound) semiconductor light emitting device and a method for manufacturing the same.
[16] Another object of the present invention is to provide a vertical structure type III- nitride compound semiconductor light emitting device, and a method for manufacturing the same.
[17] Yet another object of the present invention is to provide a Ill-nitride compound semiconductor light emitting device which includes a substrate with a groove formed therein, and a method of(for) manufacturing the same.
[18] Yet another object of the present invention is to provide a vertical structure type III- nitride compound semiconductor light emitting device which can improve external quantum efficiency, and a method of(for) manufacturing the same.
[19]
Technical Solution
[20] In order to achieve the above-described objects of the invention, there is provided a method of manufacturing a Ill-nitride compound semiconductor light emitting device including: a substrate; a plurality of nitride compound semiconductor layers being grown on the substrate, and having a first nitride compound semiconductor layer with first conductivity, a second nitride compound semiconductor layer with second conductivity different from the first conductivity, and an active layer interposed between the first nitride compound semiconductor layer and the second nitride compound semiconductor layer, for generating light by recombination of electrons and holes; and a rough surface formed on the plurality of nitride compound semiconductor layers, for externally emitting light generated in the active layer, the method including: a first step for forming the plurality of nitride compound semiconductor layers on the substrate; and a second step for forming the rough surface on the plurality of nitride compound semiconductor layers by wet etching and dry etching.
[21] In another aspect of the present invention, the method includes a step for forming a mask on the plurality of nitride compound semiconductor layers, prior to the second step.
[22] In yet another aspect of the present invention, the mask is formed by using a conductive oxide film.
[23] In yet another aspect of the present invention, the conductive oxide film is made of indium tin oxide(ITO).
[24] In yet another aspect of the present invention, there is provided a method of manufacturing a Ill-nitride compound semiconductor light emitting device including: a substrate; a plurality of nitride compound semiconductor layers being grown on the substrate, and having a first nitride compound semiconductor layer with first conductivity, a second nitride compound semiconductor layer with second conductivity different from the first conductivity, and an active layer interposed between the first nitride compound semiconductor layer and the second nitride compound semiconductor layer, for generating light by recombination of electrons and holes; and a rough surface formed on the plurality of nitride compound semiconductor layers, for externally emitting light generated in the active layer, the method including: a first step for forming the plurality of nitride compound semiconductor layers on the substrate; a second step for forming an electrode on the plurality of nitride compound semiconductor layers; a third step for wet-etching part of the electrode; and a fourth step for forming the rough surface on the plurality of nitride compound semiconductor layers by dry etching using the wet-etched electrode as a mask.
[25] In yet another aspect of the present invention, the electrode is formed by using a conductive oxide film.
[26] In yet another aspect of the present invention, the conductive oxide film is made of indium tin oxide(ITO).
[27] In yet another aspect of the present invention, there is provided a method of manufacturing a Ill-nitride compound semiconductor light emitting device, including: a first step for forming a groove in a substrate; a second step for forming a plurality of nitride compound semiconductor layers on the substrate with the groove formed therein; a third step for forming a first electrode on the plurality of nitride compound semiconductor layers; and a fourth step for forming a rough surface on the plurality of nitride compound semiconductor layers by etching the first electrode.
[28] In yet another aspect of the present invention, the method includes a fifth step for forming a second electrode to be electrically connected to the plurality of nitride compound semiconductor layers through the groove.
[29] In yet another aspect of the present invention, the method includes a step for polishing the substrate, prior to the fifth step.
[30] In yet another aspect of the present invention, the fourth step includes a wet etching process and a dry etching process.
[31] In yet another aspect of the present invention, there is provided a III- nitride compound semiconductor light emitting device including: a substrate with a groove formed therein; a plurality of nitride compound semiconductor layers being grown on
the substrate, and having a first nitride compound semiconductor layer with first conductivity, a second nitride compound semiconductor layer with second conductivity different from the first conductivity, and an active layer interposed between the first nitride compound semiconductor layer and the second nitride compound semiconductor layer, for generating light by recombination of electrons and holes; a first electrode electrically contacting the first nitride compound semiconductor layer through the groove; a second electrode formed on the plurality of nitride compound semiconductor layers; and a protrusion formed on the periphery of the second electrode, for forming a rough surface.
[32] In yet another aspect of the present invention, the protrusion is formed by etching at least the second nitride compound semiconductor layer.
[33] In yet another aspect of the present invention, the protrusion is formed on the first nitride compound semiconductor layer.
[34] In yet another aspect of the present invention, the first electrode is a reflecting film.
Advantageous Effects
[35] In accordance with the Ill-nitride compound semiconductor light emitting device, the current can be uniformly diffused in the light emitting device. [36] The vertical structure type light emitting device can be manufactured without separating the substrate from the plurality of Ill-nitride compound semiconductor layers. [37] Furthermore, the external quantum efficiency of the light emitting device can be improved. [38]
Brief Description of the Drawings [39] Fig. 1 is a cross-sectional view illustrating a conventional Ill-nitride compound semiconductor light emitting device; [40] Fig. 2 is a cross-sectional view illustrating a substrate on which a plurality of nitride compound semiconductor layers have been grown in accordance with the present invention; and [41] Fig. 3 is an explanatory view illustrating a manufacturing process of a Ill-nitride compound semiconductor light emitting device in accordance with the present invention. [42]
Mode for the Invention [43] A Ill-nitride compound semiconductor light emitting device and a method of(for) manufacturing the same in accordance with preferred embodiments of the present invention will now be described in detail with reference to the accompanying
drawings.
[44] Fig. 2 is a cross-sectional view illustrating a substrate on which a plurality of nitride compound semiconductor layers have been grown in accordance with the present invention. A buffer layer 20 is formed on a substrate 10 with grooves 80 formed therein, an n-type nitride compound semiconductor layer 30 is formed on the buffer layer 20, an active layer 40 for generating light by recombination of electron and hole is formed on the n-type nitride compound semiconductor layer 30, a p-type nitride compound semiconductor layer 50 is formed on the active layer 40, and a p-side electrode 60 is formed on the p-type nitride compound semiconductor layer 50.
[45] The grooves 80 are formed on the top surface of the substrate 10 by using a laser with a 355nm wavelength region. In a state where the laser is focused, the grooves 80 can be formed in various circular, elliptical or polygonal shapes with a diameter of a few to a few hundreds D. The depth of the grooves 80 can be controlled between a few D and a few hundreds D by energy of the laser, etc.. The grooves 80 can be formed to perfortrate the substrate 10.
[46] The buffer layer 20 formed on the substrate 10 with the grooves 80 formed therein serves to overcome differences in lattice constant and thermal expansion coefficient between the substrate 10 and the nitride compound semiconductor layer. Since the buffer layer 20 is a very thin layer with a thickness of a few tens to a few hundreds A, the buffer layer 20 is not grown in the lateral direction in the groove formed regions.
[47] The n-type nitride compound semiconductor layer 30 grown on the buffer layer 20 is grown in the lateral direction by controlling the growth conditions. During the lateral growth, the n-type nitride compound semiconductor layer 30 is grown to fill the groove formed regions. Meanwhile, openings may be formed on the grooves 80 according to the growth conditions.
[48] The p-side electrode 60 formed on the p-type nitride compound semiconductor layer 50 is made of a conductive oxide film (for example, ITO) which can make light transmit so as to emit light generated in the active layer 40. The conductive oxide film contains at least one selected from the group consisting of Zn, In, Sn, Ni, Ga, Cu, La, Ag and Al.
[49] Fig. 3 is an explanatory view illustrating a manufacturing process of a Ill-nitride compound semiconductor light emitting device in accordance with the present invention. A rough surface 70 is formed in the region except a light emitting portion 90. The region excluding the light emitting portion 90 serves as a margin space for cutting in the manufacturing process of the chip. Normally, the margin space for cutting has a size of 20 to 6OD between the devices.
[50] A photoresist 7 is deposited on the light emitting portion 90 by using a photolithography process. A wet etching process is carried out thereon by using a solution
containing HCl. It is obvious that the surface roughness of the region excluding the light emitting portion 90 is changed by a concentration of an etchant, a temperature and an etching time. For example, the wet etching process can be performed for 30 sec. by maintaining the temperature of the etchant at 45°C. A conductive oxide film 5 with a rough surface formed by the wet etching process serves as a mask in a succeeding dry etching process.
[51] Accordingly, the rough surface 70 consisting of high density protrusions can be formed by using the conductive oxide film 5 as an etch mask.
[52] After the wet etching process, the dry etching process is carried out by using, generally, plasma. A Cl group gas is used as a gas for generating plasma. The Cl group gas can be prepared by singly or mixedly using Cl , BCl , CCl and HCl. For example, the etch conditions may include 30sccm of Cl , 1.5mTorr of process pressure, 200W of ICP source RF power, 45W of RF bias (RF) power, and 20 min. of time.
[53] The conductive oxide film 5 formed in the region excluding the light emitting portion 90 is wholly removed by the wet etching process and the dry etching process. The rough surface 70 serves to increasingly externally emit light generated in the active layer. Preferably, the rough surface 70 is formed by exposing the n-type nitride compound semiconductor layer 30. However, the rough surface 70 can be formed on the active layer 40 or the p-type nitride compound semiconductor layer 50.
[54] After the rough surface 70 is formed in the region excluding the light emitting portion 90, the rear surface of the substrate 10 is polished to at least the groove formed regions by grinding or wrapping, thereby exposing the grooves 80.
[55] After the rear surface of the substrate 10 is polished, a final thickness of the substrate 10 ranges from 50 to 400D, preferably, 30 to 300D. If the final thickness of the substrate 10 is below 50D, the substrate 10 may be broken in a succeeding process, and if the final thickness is over 400D, the substrate 10 may not be easily cut by a succeeding scribing process, and the vertical structure type light emitting device may not be much improved in brightness and thermal characteristic.
[56] After the rear surface of the substrate 10 is polished, an n-side electrode 81 is formed through the exposed grooves 80. Here, the n-side electrode 81 can be formed by sputtering, E-beam evaporation or thermal deposition. The n-side electrode 81 contains any one selected from the group consisting of Ni, Au, Ag, Cr, Ti, Pt, Pd, Rh, Ir, Al, Sn, In, Ta, Cu, Co, Fe, Ru, Zr, W and Mo, or a combination thereof. Moreover, the n-side electrode 81 formed on the substrate 10 serves as an n-side bonding pad to apply the current to the semiconductor light emitting device. Meanwhile, the n-side electrode 81 can be formed on the whole substrate 10 to serve as a reflecting film.
[57] The above process is nothing but an example of the present invention. That is, it must be recognized that the present invention includes slight change of an epitaxial
structure, addition/reduction of a supplementary epitaxial layer, and addition/omission of a supplementary process.
Claims
[1] A method of manufacturing a Ill-nitride compound semiconductor light emitting device including: a substrate; a plurality of nitride compound semiconductor layers being grown on the substrate, and having a first nitride compound semiconductor layer with first conductivity, a second nitride compound semiconductor layer with second conductivity different from the first conductivity, and an active layer interposed between the first nitride compound semiconductor layer and the second nitride compound semiconductor layer, for generating light by recombination of electrons and holes; and a rough surface formed on the plurality of nitride compound semiconductor layers, for externally emitting light generated in the active layer, the method comprising: a first step for forming the plurality of nitride compound semiconductor layers on the substrate; and a second step for forming the rough surface on the plurality of nitride compound semiconductor layers by wet etching and dry etching.
[2] The method of claim 1, comprising a step for forming a mask on the plurality of nitride compound semiconductor layers, prior to the second step.
[3] The method of claim 2, wherein the mask is formed by using a conductive oxide film.
[4] The method of claim 3, wherein the conductive oxide film is made of indium tin oxide(ITO).
[5] A method of manufacturing a Ill-nitride compound semiconductor light emitting device including: a substrate; a plurality of nitride compound semiconductor layers being grown on the substrate, and having a first nitride compound semiconductor layer with first conductivity, a second nitride compound semiconductor layer with second conductivity different from the first conductivity, and an active layer interposed between the first nitride compound semiconductor layer and the second nitride compound semiconductor layer, for generating light by recombination of electrons and holes; and a rough surface formed on the plurality of nitride compound semiconductor layers, for externally emitting light generated in the active layer, the method comprising: a first step for forming the plurality of nitride compound semiconductor layers on the substrate; a second step for forming an electrode on the plurality of nitride compound semiconductor layers;
a third step for wet-etching part of the electrode; and a fourth step for forming the rough surface on the plurality of nitride compound semiconductor layers by dry etching using the wet-etched electrode as a mask. [6] The method of claim 5, wherein the electrode is formed by using a conductive oxide film. [7] The method of claim 6, wherein the conductive oxide film is made of indium tin oxide(ITO). [8] A method of manufacturing a Ill-nitride compound semiconductor light emitting device, comprising: a first step for forming a groove in a substrate; a second step for forming a plurality of nitride compound semiconductor layers on the substrate with the groove formed therein; a third step for forming a first electrode on the plurality of nitride compound semiconductor layers; and a fourth step for forming a rough surface on the plurality of nitride compound semiconductor layers by etching the first electrode. [9] The method of claim 8, comprising a fifth step for forming a second electrode to be electrically connected to the plurality of nitride compound semiconductor layers through the groove. [10] The method of claim 8, comprising a step for polishing the substrate, prior to the fifth step. [11] The method of claim 8, wherein the fourth step comprises a wet etching process and a dry etching process. [12] A Ill-nitride compound semiconductor light emitting device, comprising: a substrate with a groove formed therein; a plurality of nitride compound semiconductor layers being grown on the substrate, and having a first nitride compound semiconductor layer with first conductivity, a second nitride compound semiconductor layer with second conductivity different from the first conductivity, and an active layer interposed between the first nitride compound semiconductor layer and the second nitride compound semiconductor layer, for generating light by recombination of electrons and holes; a first electrode electrically contacting the first nitride compound semiconductor layer through the groove; a second electrode formed on the plurality of nitride compound semiconductor layers; and a protrusion formed on the periphery of the second electrode, for forming a rough surface.
[13] The Ill-nitride compound semiconductor light emitting device of claim 12, wherein the protrusion is formed by etching at least the second nitride compound semiconductor layer. [14] The III- nitride compound semiconductor light emitting device of claim 13, wherein the protrusion is formed on the first nitride compound semiconductor layer. [15] The III- nitride compound semiconductor light emitting device of claim 11, wherein the first electrode is a reflecting film.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020060060871A KR100688068B1 (en) | 2006-06-30 | 2006-06-30 | Iii-nitride semiconductor light emitting device |
| KR10-2006-0060871 | 2006-06-30 |
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| WO2008001990A1 true WO2008001990A1 (en) | 2008-01-03 |
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| PCT/KR2006/005756 WO2008001990A1 (en) | 2006-06-30 | 2006-12-27 | Iii-nitride semiconductor light emitting device and method for manufacturing the same |
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| WO (1) | WO2008001990A1 (en) |
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| CN101807645A (en) * | 2009-02-16 | 2010-08-18 | Lg伊诺特有限公司 | Semiconductor light emitting device |
| CN102479886A (en) * | 2010-11-22 | 2012-05-30 | 鼎元光电科技股份有限公司 | Method for manufacturing light emitting diode with coarsening layer |
| CN113228311A (en) * | 2021-01-14 | 2021-08-06 | 天津三安光电有限公司 | Semiconductor light-emitting element and manufacturing method thereof |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| KR101097878B1 (en) | 2009-02-11 | 2011-12-23 | 전북대학교산학협력단 | Method for manufacturing gan-based semiconductor light emitting diode |
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| JP2004297095A (en) * | 2001-11-19 | 2004-10-21 | Sanyo Electric Co Ltd | Process for fabricating compound semiconductor light emitting device |
| KR20050089120A (en) * | 2004-03-03 | 2005-09-07 | 주식회사 이츠웰 | Light emitting diode and manufacturing method of the same |
| KR20050092947A (en) * | 2004-03-17 | 2005-09-23 | (주)옵토웨이 | Anti-reflected high efficiency light emitting diode device |
| KR20060029781A (en) * | 2004-10-04 | 2006-04-07 | (주)옵토웨이 | Manufacture method of led having roughness surface |
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| KR100568298B1 (en) * | 2004-03-30 | 2006-04-05 | 삼성전기주식회사 | Nitride based semiconductor having improved external quantum efficiency and fabrication method thereof |
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2006
- 2006-06-30 KR KR1020060060871A patent/KR100688068B1/en not_active IP Right Cessation
- 2006-12-27 WO PCT/KR2006/005756 patent/WO2008001990A1/en active Application Filing
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2004297095A (en) * | 2001-11-19 | 2004-10-21 | Sanyo Electric Co Ltd | Process for fabricating compound semiconductor light emitting device |
| KR20050089120A (en) * | 2004-03-03 | 2005-09-07 | 주식회사 이츠웰 | Light emitting diode and manufacturing method of the same |
| KR20050092947A (en) * | 2004-03-17 | 2005-09-23 | (주)옵토웨이 | Anti-reflected high efficiency light emitting diode device |
| KR20060029781A (en) * | 2004-10-04 | 2006-04-07 | (주)옵토웨이 | Manufacture method of led having roughness surface |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101807645A (en) * | 2009-02-16 | 2010-08-18 | Lg伊诺特有限公司 | Semiconductor light emitting device |
| CN102479886A (en) * | 2010-11-22 | 2012-05-30 | 鼎元光电科技股份有限公司 | Method for manufacturing light emitting diode with coarsening layer |
| CN113228311A (en) * | 2021-01-14 | 2021-08-06 | 天津三安光电有限公司 | Semiconductor light-emitting element and manufacturing method thereof |
| WO2022151201A1 (en) * | 2021-01-14 | 2022-07-21 | 天津三安光电有限公司 | Semiconductor light-emitting element and method for manufacturing same |
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