WO2007089077A1 - Iii-nitride semiconductor light emitting device and method of manufacturing the same - Google Patents

Iii-nitride semiconductor light emitting device and method of manufacturing the same Download PDF

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Publication number
WO2007089077A1
WO2007089077A1 PCT/KR2006/005754 KR2006005754W WO2007089077A1 WO 2007089077 A1 WO2007089077 A1 WO 2007089077A1 KR 2006005754 W KR2006005754 W KR 2006005754W WO 2007089077 A1 WO2007089077 A1 WO 2007089077A1
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WO
WIPO (PCT)
Prior art keywords
compound semiconductor
nitride compound
ill
substrate
groove
Prior art date
Application number
PCT/KR2006/005754
Other languages
French (fr)
Inventor
Chang-Tae Kim
Jong-Won Kim
Eui-Gue Jeon
Hyun-Min Jung
Gi- Yeon Nam
Original Assignee
Epivalley Co., Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from KR20060009594A external-priority patent/KR20070079139A/en
Priority claimed from KR1020060060872A external-priority patent/KR100743471B1/en
Priority claimed from KR20060060869A external-priority patent/KR20080002199A/en
Application filed by Epivalley Co., Ltd. filed Critical Epivalley Co., Ltd.
Publication of WO2007089077A1 publication Critical patent/WO2007089077A1/en

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    • 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
    • H01L33/36—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 electrodes
    • H01L33/38—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 electrodes with a particular shape
    • H01L33/382—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 electrodes with a particular shape the electrode extending partially in or entirely through the semiconductor body
    • 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
    • H01L33/005—Processes
    • H01L33/0093—Wafer bonding; Removal of the growth substrate
    • 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
    • H01L33/26—Materials of the light emitting region
    • H01L33/30—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table
    • H01L33/32—Materials of the light emitting region containing only elements of Group III and Group V of the Periodic Table containing nitrogen

Definitions

  • the present invention relates to a Ill-nitride semiconductor light emitting device and a method of manufacturing the same, and more particularly, to a Ill-nitride semiconductor light emitting device manufactured by forming a groove in a sapphire substrate, forming a plurality of Ill-nitride semiconductor layers thereon, and connecting an electrode to the plurality of Ill-nitride compound semiconductor layers through the groove, and a method of manufacturing the same.
  • Fig. 1 is a cross-sectional view illustrating 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.
  • 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 0 C.
  • USP 5,290,393 suggests a method for growing an AI( ⁇ )Ga(-
  • Korea Patent 10-0448352 discloses a method for growing an SiC buffer layer at 600 to 99O 0 C, and growing an ln( ⁇ )Ga(i_ x )N (0 ⁇ x ⁇ 1 ) layer thereon.
  • the n-side electrode 800 formed region is doped with a dopant.
  • the n-type contact layer is made of GaN and doped with Si.
  • USP 5,733,796 teaches 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 ln( X )Ga(i- x )N (0 ⁇ x ⁇ 1 ) and comprised of single or multi well layers.
  • WO02/021121 suggests a method for partially doping a plurality of quantum well layers and barrier layers.
  • 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 0 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 NH3 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.
  • the conventional Ill-nitride compound semiconductor light emitting device mostly uses sapphire which is an insulator as the substrate 100.
  • the p-side electrode 600, the p-side bonding pad 700 and the n-side electrode 800 must be formed in the same side.
  • the conventional Ill-nitride compound semiconductor light emitting device mostly uses sapphire which is an insulator as the substrate 100.
  • the p-side electrode 600, the p-side bonding pad 700 and the n-side electrode 800 must be formed in the same side.
  • An object of the present invention is to provide a Ill-nitride compound semiconductor light emitting device and a method of manufacturing the same.
  • 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 manufacturing the same.
  • Yet another object of the present invention is to provide a flip chip type Ill-nitride compound semiconductor light emitting device which includes a substrate with a groove formed therein, and a method of manufacturing the same.
  • a method of manufacturing a Ill-nitride compound semiconductor light emitting device including a plurality of Ill-nitride compound semiconductor layers which are grown on a substrate and which include an active layer for generating light by recombination of electron and hole, the method including: a first step for forming a groove in the substrate; a second step for forming the plurality of Ill-nitride compound semiconductor layers on the substrate with the groove formed therein; a third step for polishing the resulting structure so that the plurality of Ill-nitride compound semiconductor layers formed on the substrate can be exposed through the groove; and a fourth step for electrically connecting an electrode to the Ill-nitride compound semiconductor layer through the groove.
  • the vertical structure type light emitting device in which the electrodes are positioned at the upper and lower portions of the plurality of Ill-nitride compound semiconductor layers can be manufactured without removing the whole substrate.
  • a Ill-nitride compound semiconductor light emitting device including: a first Ill-nitride compound semiconductor layer having first conductivity; a second Ill-nitride compound semiconductor layer having second conductivity different from the first conductivity; an active layer interposed between the first Ill-nitride compound semiconductor layer and the second Ill-nitride compound semiconductor layer, for generating light by recombination of electron and hole; a substrate positioned on the side of the first Ill-nitride compound semiconductor layer with regard to the active layer, a groove being formed in the substrate; a first electrode electrically connected to the first Ill-nitride compound semiconductor layer through the groove; a second electrode positioned on the side of the second Ill-nitride compound semiconductor layer with regard to the active layer, electrically connected to the second Ill-nitride compound semiconductor layer, and operated as a reflecting film; a sub-mount coupled to the second electrode; and a wire for electrically connecting the first electrode
  • the Ill-nitride compound semiconductor light emitting device includes an opening formed at the upper portion of the groove along the first Ill-nitride compound semiconductor layer, the active layer and the second Ill-nitride compound semiconductor layer.
  • a method of manufacturing a Ill-nitride compound semiconductor light emitting device including a plurality of Ill-nitride compound semiconductor layers which are grown on a substrate and which include an active layer for generating light by recombination of electron and hole, the method including: a first step for forming the plurality of Ill-nitride compound semiconductor layers on a substrate; a second step for perforating a groove through the plurality of Ill-nitride compound semiconductor layers to reach the substrate; a third step for partially removing the substrate to expose the groove; and a fourth step for electrically connecting a first electrode to the Ill-nitride compound semiconductor layer through the groove from the substrate side.
  • current is dispersed uniformly inside the light emitting device.
  • vertical structure type light emitting device can be formed without separating substrate from the plurality of Ill-nitride compound semiconductor layers.
  • 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 one example of a substrate of a Ill-nitride compound semiconductor light emitting device in accordance with the present invention
  • Fig. 3 is a photograph showing a sapphire substrate with a groove formed therein by a laser
  • Fig. 4 is an explanatory view illustrating a manufacturing process of a Ill-nitride compound semiconductor light emitting device in accordance with the present invention
  • Fig. 5 is a photograph showing a nitride compound semiconductor layer formed on a sapphire substrate with a groove formed therein;
  • Fig. 6 is another explanatory view illustrating the manufacturing process of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • Fig. 7 is yet another explanatory view illustrating the manufacturing process of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • Fig. 8 is a cross-sectional view illustrating one example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • Fig. 9 is a cross-sectional view illustrating another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • Fig. 10 is a cross-sectional view illustrating an example of a passivation film for protecting nitride compound semiconductor layers of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention
  • Fig. 11 is a cross-sectional view illustrating yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • Fig. 12 is a cross-sectional view illustrating yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention
  • Fig. 13 is an explanatory view illustrating a first step of a manufacturing process of yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention
  • Fig. 14 is an explanatory view illustrating a second step of the manufacturing process of yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • Fig. 15 is an explanatory view illustrating a third step of the manufacturing process of yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • Fig. 16 is an explanatory view illustrating a fourth step of the manufacturing process of yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • Fig. 17 is an explanatory view illustrating a fifth step of the manufacturing process of yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • Fig. 2 is a cross-sectional view illustrating one example of a substrate of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • Grooves 80 and 81 are formed on a top surface of a sapphire substrate 10 by irradiating laser beams.
  • a method for forming the grooves 80 and 81 on the top surface of the sapphire substrate 10 uses a laser with a 355nm wavelength region. In a state where the laser is focused, the grooves 80 and 81 can be formed in various circular, elliptical or polygonal shapes with a diameter of a few to a few hundreds ⁇ m.
  • the depth of the grooves 80 and 81 can be controlled between a few ⁇ m and a few hundreds ⁇ m by energy of the laser.
  • the grooves 80 and 81 can be formed to pass through the sapphire substrate 10.
  • Fig. 3 is a photograph showing a sapphire substrate with a groove formed therein by a laser, particularly, a cross-sectional view observed through a scanning electron microscope.
  • a groove 80 is formed in a substrate 10 by using a diode pumped solid state (DPSS) laser with an active medium of neodymium-doped yttrium aluminum garnet (Nd:YAG) and a wavelength of 355nm.
  • DPSS diode pumped solid state
  • Nd:YAG neodymium-doped yttrium aluminum garnet
  • the groove 80 with a length of 300 ⁇ m and a width of 10 ⁇ m is formed in the substrate 10.
  • Fig. 4 is an explanatory view illustrating a manufacturing process of a Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • a plurality of nitride compound semiconductor layers are grown on a sapphire substrate 10 with a groove formed therein.
  • the plurality of nitride compound semiconductor layers include an n-type nitride compound semiconductor layer 20, an active layer 30 epitaxially grown on the n-type nitride compound semiconductor layer 20, for generating light by recombination of electron and hole, and a p-type nitride compound semiconductor layer 40 epitaxially grown on the active layer 30.
  • the n-type nitride compound semiconductor layer 20 is made of GaN, and an n-type impurity is doped thereon. Si is used as the n-type impurity.
  • a doping concentration of the impurity ranges from 1x10 1 7 to 1x1 ⁇ 2O/cm3.
  • f the doping concentration is below 1x10 17 /cm 3 , ohmic contact may not be expected due to high resistance of the semiconductor layer 20, and if the doping concentration is over
  • the crystallinity of the semiconductor layer 20 may be deteriorated.
  • a thickness of the n-type nitride compound semiconductor layer 20 ranges from 2 to 6 ⁇ m. If the thickness of the semiconductor layer 20 is over 6 ⁇ m, the crystallinity of the semiconductor layer 20 may be reduced to cause the detrimental effect on the device, and if the thickness is below 2 ⁇ m, electrons may not be smoothly supplied.
  • a growth temperature of the n-type nitride compound semiconductor layer 20 ranges from 600 to
  • the active layer 30 for generating light by recombination of electron and hole has a single or multi quantum well structure such as InGaN/lnGaN (different in composition).
  • a thickness of an InGaN well layer ranges from 10 to
  • a growth temperature thereof ranges from 600 to 1000 0 C.
  • a thickness of an InGaN barrier layer ranges from 30 to
  • the p-type nitride compound semiconductor layer 40 is made of GaN, and a p-type impurity is doped thereon. Mg is used as the p-type impurity.
  • a doping concentration of the impurity ranges from 1x1 O ⁇ 7 to 1x1 ⁇ 2O/cm3. If the doping concentration is below ixiO ⁇ /cm ⁇ , the p-type nitride compound semiconductor layer 40 may not be normally operated, and if the doping concentration is over 1x1020/cm3, the crystallinity of the semiconductor layer 40 may be deteriorated.
  • a thickness of the p-type nitride compound semiconductor layer 40 ranges from 200 to 3000A. If the thickness of the semiconductor layer 40 is over 3000A, the crystallinity of the semiconductor layer 40 may be reduced to cause the detrimental effect on the device, and if the thickness is below 200A, holes may not be smoothly supplied.
  • a growth temperature of the p-type nitride compound semiconductor layer 40 ranges from 600 to 1100 0 C. If the growth temperature is below 600 0 C, the crystallinity of the semiconductor layer 40 may be deteriorated, and if the growth temperature is over 1100 0 C, the surface of the semiconductor layer 40 may be roughened to cause the detrimental effect on the crystallinity of the semiconductor layer 40.
  • Fig. 5 is a photograph showing a nitride compound semiconductor layer formed on a sapphire substrate with a groove formed therein, particularly, a cross-sectional view observed through a scanning electron microscope.
  • a semiconductor layer 21 grown on a sapphire substrate 10 with a groove 80 formed therein is an undoped GaN layer.
  • a pressure of a reactor is 200torr
  • 3 ⁇ m of GaN layer is grown by using TMGa and NH3
  • a growth temperature is 1050 0 C.
  • Fig. 6 is another explanatory view illustrating the manufacturing process of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • a light transmitting electrode 50 and a p-side bonding pad 60 for current supply are formed on the p-type nitride compound semiconductor layer 40.
  • the light transmitting electrode 50 contains at least one selected from the group consisting of Ni, Au, Ag, Cr, Ti, Pt, Pd, Rh, Ir, Al, Sn, ITO, IZO, ZnO, CIO, In, Ta, Cu, Co, Fe, Ru, Zr, W and Mo.
  • the p-side bonding pad 60 for supplying the current is formed at the upper portions of the light transmitting electrode 50 and the p-type nitride compound semiconductor layer 40.
  • the p-side bonding pad 60 contains at least 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.
  • a passivation film such as SiO x , SiN x , SiON, BCB or polyimide can be formed on the whole or partial surface except the bonding pad 60.
  • Fig. 7 is yet another explanatory view illustrating the manufacturing process of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • a bottom surface of a sapphire substrate 11 on which a nitride compound semiconductor layer is not grown is polished.
  • the sapphire substrate 11 is polished to at least a groove formed region by grinding or wrapping, thereby exposing the groove.
  • a final thickness of the sapphire substrate 11 ranges from 50 to 400 ⁇ m, preferably, 30 to 300 ⁇ m, If the final thickness of the sapphire substrate 11 is below 50 ⁇ m, the sapphire substrate 11 may be broken in a succeeding process, and if the final thickness is over 400 ⁇ m, the sapphire substrate 11 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.
  • Fig. 8 is a cross-sectional view illustrating one example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • An n-side electrode 70 is formed on the bottom surface of the polished sapphire substrate 11 and the n-type nitride compound semiconductor layer exposed through the groove.
  • the n-side electrode 70 can be formed by sputtering, E-beam evaporation or thermal deposition.
  • the n-side electrode 70 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 71 formed on the sapphire substrate 11 serves as an n-side bonding pad to apply the current to the semiconductor light emitting device.
  • Fig. 9 is a cross-sectional view illustrating another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • the light emitting device includes a substrate 110 with a groove 111 formed therein, a buffer layer 120 grown on the substrate 110, an n-type nitride compound semiconductor layer 130 grown on the buffer layer 120, an active layer 140 grown on the n-type nitride compound semiconductor layer 130, a p-type nitride compound semiconductor layer 150 grown on the active layer 140, a p-side electrode 160 formed on the p-type nitride compound semiconductor layer 150, and an n-side electrode 170 formed on the n-type nitride compound semiconductor layer 130 exposed through the groove 111 and the rear surface of the substrate 110.
  • a sapphire substrate is used as the substrate 110 with the groove 111 formed therein.
  • the circular groove 111 can be formed in the sapphire substrate 110 under the conditions of an active medium of Nd-YAG, 532nm of DPSS type wavelength, 10W (10 to 100KHz) of laser output and 20 to 50 holes/sec, of drilling speed.
  • the substrate 110 is preferably organic-washed by using an acid such as a phosphoric acid and finally Dl-processed.
  • the buffer layer 120 grown on the substrate 110 with the groove 111 is a very thin layer, it is not sufficiently grown in the lateral direction. Accordingly, the buffer layer 120 is grown only on the substrate 110 without covering the groove 111. The succeeding n-type nitride compound semiconductor layer 130 is grown to cover the groove 111 according to the lateral growth condition.
  • the p-side electrode 160 formed on the p-type nitride compound semiconductor layer 150 is a metal layer with high reflectivity.
  • the p-side electrode 160 is deposited by 100 to 1000A, by using a metal having an ohmic contact characteristic to the p-type nitride compound semiconductor layer 150 and having high reflectivity, such as Al, Ag, Pt and Pd.
  • a passivation film 190 such as SiO x , SiN x , SiON, BCB or polyimide can be formed on some of the plurality of nitride compound semiconductor layers.
  • a process of polishing the bottom surface of the sapphire substrate 110 to at least the groove formed region is carried out. That is, the sapphire substrate 110 is polished to at least the groove formed region by grinding or wrapping, to expose the groove 111.
  • the n-side electrode 170 is formed on the bottom surface of the n-type nitride compound semiconductor layer 130 and the substrate 110 through the polished substrate 110 and the groove 111.
  • the n-side electrode 170 is made of metal and metal oxide which can make light transmit so as to emit light generated in the active layer 140.
  • the n-side electrode 170 contains any one selected from the group consisting of Ni, Au, Ag, Cr, Ti, Pt, Pd, Rh, Ir, Al, Sn, ITO, IZO, ZnO, CIO, In, Ta, Cu, Co, Fe, Ru, Zr, W and Mo.
  • n-side bonding pad 171 for current supply is formed on the n-side electrode 170.
  • the n-side bonding pad 171 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.
  • Fig. 11 shows a state where the chip manufactured by the above process is mounted on a sub-mount 190.
  • Fig. 12 is a cross-sectional view illustrating yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • the Ill-nitride compound semiconductor light emitting device includes a substrate 110 with a groove 111 formed therein, and a plurality of nitride compound semiconductor layers.
  • the plurality of nitride compound semiconductor layers include a buffer layer 120, an n-type nitride compound semiconductor layer 130, an active layer 140, a p-type nitride compound semiconductor layer 150, a p-side electrode 160 with high reflectivity formed on the p-type nitride compound semiconductor layer 150, an n-side electrode 170 which can make light transmit, and a passivation film 180 for protecting the plurality of nitride compound semiconductor layers exposed through an opening 112.
  • the opening 112 can be formed by controlling a growth condition to prevent the lateral growth around the groove 111 during the growth of the n-type nitride compound semiconductor layer 130, or by enlarging the groove 111.
  • Fig. 13 is an explanatory view illustrating a first step of a manufacturing process of yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • the Ill-nitride compound semiconductor light emitting device includes a substrate 210, a buffer layer 220 grown on the substrate 210, an n-type nitride compound semiconductor layer 230 grown on the buffer layer 220, an active layer 240 grown on the n-type nitride compound semiconductor layer 230, and a p-type nitride compound semiconductor layer 250 grown on the active layer 240.
  • the plurality of grown nitride compound semiconductor layers are nothing but an example of the present invention. It must be recognized that the present invention includes slight change of an epitaxial structure or addition/omission of an epitaxial layer.
  • Fig. 14 is an explanatory view illustrating a second step of the manufacturing process of yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • Grooves 290 are formed on the laminated structure including the nitride compound semiconductor layers grown on the substrate 210.
  • each groove 290 has a diameter of 30 ⁇ m.
  • the grooves 290 can be formed at periodical intervals of 200 ⁇ m in the x axis direction and 250 ⁇ m in the y axis direction from one groove 290.
  • Fig. 15 is an explanatory view illustrating a third step of the manufacturing process of yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • a p-side electrode 260, a p-side bonding pad 261 and an n-side electrode 270 are formed on the plurality of nitride compound semiconductor layers with the groove.
  • a process of exposing an n-type nitride compound semiconductor layer 231 is performed to form the n-side electrode 270.
  • the n-type nitride compound semiconductor layer 231 can be exposed by dry etching or wet etching.
  • the n-type nitride compound semiconductor layer 231 can be etched to have one step.
  • the p-side bonding pad 261 and the n-side electrode 270 are formed.
  • the p-side bonding pad 261 and the n-side electrode 270 can be formed by one process.
  • the p-side bonding pad 261 is formed on the p-side electrode 260 and part of the p-type nitride compound semiconductor layer 250, and the n-side electrode 270 is formed on the exposed n-type nitride compound semiconductor layer 231.
  • Fig. 16 is an explanatory view illustrating a fourth step of the manufacturing process of yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • the rear surface of the substrate 210 is polished.
  • the substrate 210 is polished to at least the groove formed region, so that the groove 290 passes through the substrate 210.
  • the substrate 210 can be polished by grinding or wrapping.
  • the final thickness of the substrate 210 ranges from 50 to 400 ⁇ m, preferably, 30 to 300 ⁇ m.
  • the substrate 210 may be broken in a succeeding process, and if the final thickness of the substrate 210 is over 300 ⁇ m, the vertical structure type light emitting device may not be much improved in brightness and thermal characteristic.
  • Fig. 17 is an explanatory view illustrating a fifth step of the manufacturing process of yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
  • a substrate side n-side electrode 271 is formed to apply the current through the n-side electrode 270.
  • the substrate side n-side electrode 271 is formed on the rear surface of the polished substrate 210, and electrically connected to the n-side electrode 270 through the groove 290.
  • a contact area between the n-type nitride compound semiconductor layer and the electrode is enlarged so that the electrons can be surely supplied to the plurality of nitride compound semiconductor layers.
  • the substrate side n-side electrode 271 can be formed by sputtering, E-beam evaporation or thermal deposition.
  • the substrate side n-side electrode 271 contains any one selected from the group consisting of Ni, Au, Ag, Cr 1 Ti, Pt, Pd, Rh, Ir, Al, Sn, In, Ta, Cu, Co, Fe, Ru, Zr, W and Mo, or a combination thereof, and serves as a reflecting film.
  • the substrate side n-side electrode 271 is formed as a reflecting film to reflect light generated in the active layer, thereby emitting the generated light to the upper portion of the light emitting device.
  • 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.

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Abstract

The present invention discloses a Ill-nitride compound semiconductor light emitting device and a method of manufacturing the same. In the method of manufacturing the Ill-nitride compound semiconductor light emitting device including a plurality of Ill-nitride compound semiconductor layers which are grown on a substrate and which include an active layer for generating light by recombination of electron and hole, the method includes a first step for forming a groove in the substrate, a second step for forming the plurality of Ill-nitride compound semiconductor layers on the substrate with the groove formed therein, a third step for polishing the resulting structure so that the plurality of Ill-nitride compound semiconductor layers formed on the substrate can be exposed through the groove, and a fourth step for electrically connecting an electrode to the Ill-nitride compound semiconductor layer through the groove.

Description

[DESCRIPTION] [Invention Title]
III-NITRIDE SEMICONDUCTOR LIGHT EMITTING DEVICE AND METHOD OF MANUFACTURING THE SAME
[Technical Field]
The present invention relates to a Ill-nitride semiconductor light emitting device and a method of manufacturing the same, and more particularly, to a Ill-nitride semiconductor light emitting device manufactured by forming a groove in a sapphire substrate, forming a plurality of Ill-nitride semiconductor layers thereon, and connecting an electrode to the plurality of Ill-nitride compound semiconductor layers through the groove, and a method of manufacturing the same.
[Background Art]
Fig. 1 is a cross-sectional view illustrating 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.
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.
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 8000C. USP 5,290,393 suggests a method for growing an AI(χ)Ga(-|-χ)N (0≤x<1 ) buffer layer having a thickness of 10 to 5000A on a
sapphire substrate at 200 to 9000C. Korea Patent 10-0448352 discloses a method for growing an SiC buffer layer at 600 to 99O0C, and growing an ln(χ)Ga(i_x)N (0<x≤1 ) layer thereon.
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 teaches 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. Normally, the active layer 400 is made of ln(X)Ga(i-x)N (0<x≤1 ) and comprised of single or multi well layers. WO02/021121 suggests a method for partially doping a plurality of quantum well layers and barrier layers.
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 4000C. 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 NH3 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.
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.
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.
The conventional Ill-nitride compound semiconductor light emitting device mostly uses sapphire which is an insulator as the substrate 100. As a result, the p-side electrode 600, the p-side bonding pad 700 and the n-side electrode 800 must be formed in the same side.
[Disclosure] [Technical Problem]
The conventional Ill-nitride compound semiconductor light emitting device mostly uses sapphire which is an insulator as the substrate 100. As a result, the p-side electrode 600, the p-side bonding pad 700 and the n-side electrode 800 must be formed in the same side.
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 of manufacturing the same.
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 manufacturing the same.
Yet another object of the present invention is to provide a flip chip type Ill-nitride compound semiconductor light emitting device which includes a substrate with a groove formed therein, and a method of manufacturing the same.
[Technical Solution]
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 plurality of Ill-nitride compound semiconductor layers which are grown on a substrate and which include an active layer for generating light by recombination of electron and hole, the method including: a first step for forming a groove in the substrate; a second step for forming the plurality of Ill-nitride compound semiconductor layers on the substrate with the groove formed therein; a third step for polishing the resulting structure so that the plurality of Ill-nitride compound semiconductor layers formed on the substrate can be exposed through the groove; and a fourth step for electrically connecting an electrode to the Ill-nitride compound semiconductor layer through the groove. According to the above method, the vertical structure type light emitting device in which the electrodes are positioned at the upper and lower portions of the plurality of Ill-nitride compound semiconductor layers can be manufactured without removing the whole substrate.
In another aspect of the present invention, there is provided a Ill-nitride compound semiconductor light emitting device, including: a first Ill-nitride compound semiconductor layer having first conductivity; a second Ill-nitride compound semiconductor layer having second conductivity different from the first conductivity; an active layer interposed between the first Ill-nitride compound semiconductor layer and the second Ill-nitride compound semiconductor layer, for generating light by recombination of electron and hole; a substrate positioned on the side of the first Ill-nitride compound semiconductor layer with regard to the active layer, a groove being formed in the substrate; a first electrode electrically connected to the first Ill-nitride compound semiconductor layer through the groove; a second electrode positioned on the side of the second Ill-nitride compound semiconductor layer with regard to the active layer, electrically connected to the second Ill-nitride compound semiconductor layer, and operated as a reflecting film; a sub-mount coupled to the second electrode; and a wire for electrically connecting the first electrode to the sub-mount. By this configuration, the number of the wire connections between the flip chip and the sub-mount is reduced to simplify the process.
In another aspect of the present invention, the Ill-nitride compound semiconductor light emitting device includes an opening formed at the upper portion of the groove along the first Ill-nitride compound semiconductor layer, the active layer and the second Ill-nitride compound semiconductor layer. By this configuration, the size of the groove can be enlarged. Therefore, heat generated in the light emitting device can be easily emitted through the enlarged groove. Moreover, the first electrode can be stably electrically connected to the first Ill-nitride compound semiconductor layer through the enlarged groove.
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 plurality of Ill-nitride compound semiconductor layers which are grown on a substrate and which include an active layer for generating light by recombination of electron and hole, the method including: a first step for forming the plurality of Ill-nitride compound semiconductor layers on a substrate; a second step for perforating a groove through the plurality of Ill-nitride compound semiconductor layers to reach the substrate; a third step for partially removing the substrate to expose the groove; and a fourth step for electrically connecting a first electrode to the Ill-nitride compound semiconductor layer through the groove from the substrate side. According to the above method, after the plurality of Ill-nitride compound semiconductor layers are stably grown on the substrate which does not have a groove, the vertical structure type light emitting device can be formed.
[Advantageous Effects]
In accordance with the present invention, current is dispersed uniformly inside the light emitting device.
In another aspect of the present invention, vertical structure type light emitting device can be formed without separating substrate from the plurality of Ill-nitride compound semiconductor layers.
[Description of Drawings]
The present invention will become better understood with reference to the accompanying drawings which are given only by way of illustration and thus are not limitative of the present invention, wherein:
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 one example of a substrate of a Ill-nitride compound semiconductor light emitting device in accordance with the present invention;
Fig. 3 is a photograph showing a sapphire substrate with a groove formed therein by a laser; Fig. 4 is an explanatory view illustrating a manufacturing process of a Ill-nitride compound semiconductor light emitting device in accordance with the present invention;
Fig. 5 is a photograph showing a nitride compound semiconductor layer formed on a sapphire substrate with a groove formed therein;
Fig. 6 is another explanatory view illustrating the manufacturing process of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention;
Fig. 7 is yet another explanatory view illustrating the manufacturing process of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention;
Fig. 8 is a cross-sectional view illustrating one example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention;
Fig. 9 is a cross-sectional view illustrating another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention;
Fig. 10 is a cross-sectional view illustrating an example of a passivation film for protecting nitride compound semiconductor layers of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention;
Fig. 11 is a cross-sectional view illustrating yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention;
Fig. 12 is a cross-sectional view illustrating yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention; Fig. 13 is an explanatory view illustrating a first step of a manufacturing process of yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention;
Fig. 14 is an explanatory view illustrating a second step of the manufacturing process of yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention;
Fig. 15 is an explanatory view illustrating a third step of the manufacturing process of yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention;
Fig. 16 is an explanatory view illustrating a fourth step of the manufacturing process of yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention; and
Fig. 17 is an explanatory view illustrating a fifth step of the manufacturing process of yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention.
[Mode for Invention]
A Ill-nitride compound semiconductor light emitting device and a method of manufacturing the same in accordance with preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
Fig. 2 is a cross-sectional view illustrating one example of a substrate of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention. Grooves 80 and 81 are formed on a top surface of a sapphire substrate 10 by irradiating laser beams. A method for forming the grooves 80 and 81 on the top surface of the sapphire substrate 10 uses a laser with a 355nm wavelength region. In a state where the laser is focused, the grooves 80 and 81 can be formed in various circular, elliptical or polygonal shapes with a diameter of a few to a few hundreds μm. The depth of the grooves 80 and 81 can be controlled between a few μm and a few hundreds μm by energy of the laser. The grooves 80 and 81 can be formed to pass through the sapphire substrate 10.
Fig. 3 is a photograph showing a sapphire substrate with a groove formed therein by a laser, particularly, a cross-sectional view observed through a scanning electron microscope. A groove 80 is formed in a substrate 10 by using a diode pumped solid state (DPSS) laser with an active medium of neodymium-doped yttrium aluminum garnet (Nd:YAG) and a wavelength of 355nm. In a state where an output of the laser is 0.4W (50KHz) and a scanning speed is 3mm/sec, the groove 80 with a length of 300μm and a width of 10μm is formed in the substrate 10.
Fig. 4 is an explanatory view illustrating a manufacturing process of a Ill-nitride compound semiconductor light emitting device in accordance with the present invention. A plurality of nitride compound semiconductor layers are grown on a sapphire substrate 10 with a groove formed therein. The plurality of nitride compound semiconductor layers include an n-type nitride compound semiconductor layer 20, an active layer 30 epitaxially grown on the n-type nitride compound semiconductor layer 20, for generating light by recombination of electron and hole, and a p-type nitride compound semiconductor layer 40 epitaxially grown on the active layer 30.
In accordance with the present invention, the n-type nitride compound semiconductor layer 20 is made of GaN, and an n-type impurity is doped thereon. Si is used as the n-type impurity. A doping concentration of the impurity ranges from 1x101 7 to 1x1θ2O/cm3. |f the doping concentration is below 1x1017/cm3, ohmic contact may not be expected due to high resistance of the semiconductor layer 20, and if the doping concentration is over
1x10.20/cm3, the crystallinity of the semiconductor layer 20 may be deteriorated.
Preferably, a thickness of the n-type nitride compound semiconductor layer 20 ranges from 2 to 6μm. If the thickness of the semiconductor layer 20 is over 6μm, the crystallinity of the semiconductor layer 20 may be reduced to cause the detrimental effect on the device, and if the thickness is below 2μm, electrons may not be smoothly supplied. Preferably, a growth temperature of the n-type nitride compound semiconductor layer 20 ranges from 600 to
11000C. If the growth temperature is below 6000C, the crystallinity of the semiconductor layer 20 may be deteriorated, and if the growth temperature is over 11000C, the surface of the semiconductor layer 20 may be roughened to cause the detrimental effect on the crystallinity of the semiconductor layer 20. When the n-type nitride compound semiconductor layer 20 is grown on the sapphire substrate 10 with the groove formed therein, the n-type nitride compound semiconductor layer 20 is grown in the lateral direction. Therefore, the semiconductor layer 20 is formed not inside the groove but on the groove. The active layer 30 for generating light by recombination of electron and hole has a single or multi quantum well structure such as InGaN/lnGaN (different in composition). Preferably, a thickness of an InGaN well layer ranges from 10 to
100A, and a growth temperature thereof ranges from 600 to 10000C. In addition, preferably, a thickness of an InGaN barrier layer ranges from 30 to
15θA, and a growth temperature thereof ranges from 600 to 11000C. The p-type nitride compound semiconductor layer 40 is made of GaN, and a p-type impurity is doped thereon. Mg is used as the p-type impurity. A doping concentration of the impurity ranges from 1x1 O^ 7 to 1x1θ2O/cm3. If the doping concentration is below ixiO^/cm^, the p-type nitride compound semiconductor layer 40 may not be normally operated, and if the doping concentration is over 1x1020/cm3, the crystallinity of the semiconductor layer 40 may be deteriorated.
Preferably, a thickness of the p-type nitride compound semiconductor layer 40 ranges from 200 to 3000A. If the thickness of the semiconductor layer 40 is over 3000A, the crystallinity of the semiconductor layer 40 may be reduced to cause the detrimental effect on the device, and if the thickness is below 200A, holes may not be smoothly supplied. Preferably, a growth temperature of the p-type nitride compound semiconductor layer 40 ranges from 600 to 11000C. If the growth temperature is below 6000C, the crystallinity of the semiconductor layer 40 may be deteriorated, and if the growth temperature is over 11000C, the surface of the semiconductor layer 40 may be roughened to cause the detrimental effect on the crystallinity of the semiconductor layer 40.
Fig. 5 is a photograph showing a nitride compound semiconductor layer formed on a sapphire substrate with a groove formed therein, particularly, a cross-sectional view observed through a scanning electron microscope. A semiconductor layer 21 grown on a sapphire substrate 10 with a groove 80 formed therein is an undoped GaN layer.
During the growth, a pressure of a reactor is 200torr, 3μm of GaN layer is grown by using TMGa and NH3, and a growth temperature is 10500C.
Fig. 6 is another explanatory view illustrating the manufacturing process of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention. A light transmitting electrode 50 and a p-side bonding pad 60 for current supply are formed on the p-type nitride compound semiconductor layer 40.
The light transmitting electrode 50 contains at least one selected from the group consisting of Ni, Au, Ag, Cr, Ti, Pt, Pd, Rh, Ir, Al, Sn, ITO, IZO, ZnO, CIO, In, Ta, Cu, Co, Fe, Ru, Zr, W and Mo.
The p-side bonding pad 60 for supplying the current is formed at the upper portions of the light transmitting electrode 50 and the p-type nitride compound semiconductor layer 40. In addition, the p-side bonding pad 60 contains at least 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.
After the light transmitting electrode 50 and the p-side bonding pad 60 are formed, a passivation film such as SiOx, SiNx, SiON, BCB or polyimide can be formed on the whole or partial surface except the bonding pad 60.
Fig. 7 is yet another explanatory view illustrating the manufacturing process of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention. A bottom surface of a sapphire substrate 11 on which a nitride compound semiconductor layer is not grown is polished. In the process of polishing the bottom surface of the sapphire substrate 11 , the sapphire substrate 11 is polished to at least a groove formed region by grinding or wrapping, thereby exposing the groove.
After the bottom surface of the sapphire substrate 11 is polished, a final thickness of the sapphire substrate 11 ranges from 50 to 400μm, preferably, 30 to 300μm, If the final thickness of the sapphire substrate 11 is below 50μm, the sapphire substrate 11 may be broken in a succeeding process, and if the final thickness is over 400μm, the sapphire substrate 11 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.
Fig. 8 is a cross-sectional view illustrating one example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention. An n-side electrode 70 is formed on the bottom surface of the polished sapphire substrate 11 and the n-type nitride compound semiconductor layer exposed through the groove.
The n-side electrode 70 can be formed by sputtering, E-beam evaporation or thermal deposition. The n-side electrode 70 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 71 formed on the sapphire substrate 11 serves as an n-side bonding pad to apply the current to the semiconductor light emitting device.
Fig. 9 is a cross-sectional view illustrating another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention. The light emitting device includes a substrate 110 with a groove 111 formed therein, a buffer layer 120 grown on the substrate 110, an n-type nitride compound semiconductor layer 130 grown on the buffer layer 120, an active layer 140 grown on the n-type nitride compound semiconductor layer 130, a p-type nitride compound semiconductor layer 150 grown on the active layer 140, a p-side electrode 160 formed on the p-type nitride compound semiconductor layer 150, and an n-side electrode 170 formed on the n-type nitride compound semiconductor layer 130 exposed through the groove 111 and the rear surface of the substrate 110.
Generally, a sapphire substrate is used as the substrate 110 with the groove 111 formed therein. As one example of forming the groove 111 in the substrate 110, the circular groove 111 can be formed in the sapphire substrate 110 under the conditions of an active medium of Nd-YAG, 532nm of DPSS type wavelength, 10W (10 to 100KHz) of laser output and 20 to 50 holes/sec, of drilling speed. Thereafter, in order to remove deposits, the substrate 110 is preferably organic-washed by using an acid such as a phosphoric acid and finally Dl-processed.
As the buffer layer 120 grown on the substrate 110 with the groove 111 is a very thin layer, it is not sufficiently grown in the lateral direction. Accordingly, the buffer layer 120 is grown only on the substrate 110 without covering the groove 111. The succeeding n-type nitride compound semiconductor layer 130 is grown to cover the groove 111 according to the lateral growth condition.
The p-side electrode 160 formed on the p-type nitride compound semiconductor layer 150 is a metal layer with high reflectivity. The p-side electrode 160 is deposited by 100 to 1000A, by using a metal having an ohmic contact characteristic to the p-type nitride compound semiconductor layer 150 and having high reflectivity, such as Al, Ag, Pt and Pd.
If necessary, as shown in Fig. 10, in order to protect the plurality of exposed nitride compound semiconductor layers, a passivation film 190 such as SiOx, SiNx, SiON, BCB or polyimide can be formed on some of the plurality of nitride compound semiconductor layers.
Then, a process of polishing the bottom surface of the sapphire substrate 110 to at least the groove formed region is carried out. That is, the sapphire substrate 110 is polished to at least the groove formed region by grinding or wrapping, to expose the groove 111.
The n-side electrode 170 is formed on the bottom surface of the n-type nitride compound semiconductor layer 130 and the substrate 110 through the polished substrate 110 and the groove 111. The n-side electrode 170 is made of metal and metal oxide which can make light transmit so as to emit light generated in the active layer 140. The n-side electrode 170 contains any one selected from the group consisting of Ni, Au, Ag, Cr, Ti, Pt, Pd, Rh, Ir, Al, Sn, ITO, IZO, ZnO, CIO, In, Ta, Cu, Co, Fe, Ru, Zr, W and Mo.
An n-side bonding pad 171 for current supply is formed on the n-side electrode 170. The n-side bonding pad 171 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.
Fig. 11 shows a state where the chip manufactured by the above process is mounted on a sub-mount 190.
Fig. 12 is a cross-sectional view illustrating yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention. The Ill-nitride compound semiconductor light emitting device includes a substrate 110 with a groove 111 formed therein, and a plurality of nitride compound semiconductor layers. The plurality of nitride compound semiconductor layers include a buffer layer 120, an n-type nitride compound semiconductor layer 130, an active layer 140, a p-type nitride compound semiconductor layer 150, a p-side electrode 160 with high reflectivity formed on the p-type nitride compound semiconductor layer 150, an n-side electrode 170 which can make light transmit, and a passivation film 180 for protecting the plurality of nitride compound semiconductor layers exposed through an opening 112.
The opening 112 can be formed by controlling a growth condition to prevent the lateral growth around the groove 111 during the growth of the n-type nitride compound semiconductor layer 130, or by enlarging the groove 111.
Fig. 13 is an explanatory view illustrating a first step of a manufacturing process of yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention. The Ill-nitride compound semiconductor light emitting device includes a substrate 210, a buffer layer 220 grown on the substrate 210, an n-type nitride compound semiconductor layer 230 grown on the buffer layer 220, an active layer 240 grown on the n-type nitride compound semiconductor layer 230, and a p-type nitride compound semiconductor layer 250 grown on the active layer 240. The plurality of grown nitride compound semiconductor layers are nothing but an example of the present invention. It must be recognized that the present invention includes slight change of an epitaxial structure or addition/omission of an epitaxial layer.
Fig. 14 is an explanatory view illustrating a second step of the manufacturing process of yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention. Grooves 290 are formed on the laminated structure including the nitride compound semiconductor layers grown on the substrate 210.
For example, each groove 290 has a diameter of 30μm. The grooves 290 can be formed at periodical intervals of 200μm in the x axis direction and 250μm in the y axis direction from one groove 290.
In addition, after the plurality of nitride compound semiconductor layers are formed on the substrate 210, the groove 290 can be formed to pass through the substrate 210 and the plurality of nitride compound semiconductor layers from the rear surface of the substrate 210. However, in this case, since the substrate 210 is thick, it takes a long time to perforate the groove 290 through the substrate 210 by using a laser. Moreover, drilling efficiency of the laser is reduced. Fig. 15 is an explanatory view illustrating a third step of the manufacturing process of yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention. A p-side electrode 260, a p-side bonding pad 261 and an n-side electrode 270 are formed on the plurality of nitride compound semiconductor layers with the groove.
After the p-side electrode 260 is formed, a process of exposing an n-type nitride compound semiconductor layer 231 is performed to form the n-side electrode 270. The n-type nitride compound semiconductor layer 231 can be exposed by dry etching or wet etching. Here, in order to increase the exposed surface area, the n-type nitride compound semiconductor layer 231 can be etched to have one step.
After the etching process of exposing the n-type nitride compound semiconductor layer 231 , the p-side bonding pad 261 and the n-side electrode 270 are formed. The p-side bonding pad 261 and the n-side electrode 270 can be formed by one process. The p-side bonding pad 261 is formed on the p-side electrode 260 and part of the p-type nitride compound semiconductor layer 250, and the n-side electrode 270 is formed on the exposed n-type nitride compound semiconductor layer 231.
Fig. 16 is an explanatory view illustrating a fourth step of the manufacturing process of yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention. The rear surface of the substrate 210 is polished. At this time, the substrate 210 is polished to at least the groove formed region, so that the groove 290 passes through the substrate 210. The substrate 210 can be polished by grinding or wrapping. After the rear surface of the substrate 210 is polished to at least the groove formed region, the final thickness of the substrate 210 ranges from 50 to 400μm, preferably, 30 to 300μm. If the final thickness of the substrate 210 is below 30μm, the substrate 210 may be broken in a succeeding process, and if the final thickness of the substrate 210 is over 300μm, the vertical structure type light emitting device may not be much improved in brightness and thermal characteristic.
Fig. 17 is an explanatory view illustrating a fifth step of the manufacturing process of yet another example of the Ill-nitride compound semiconductor light emitting device in accordance with the present invention. A substrate side n-side electrode 271 is formed to apply the current through the n-side electrode 270. The substrate side n-side electrode 271 is formed on the rear surface of the polished substrate 210, and electrically connected to the n-side electrode 270 through the groove 290. A contact area between the n-type nitride compound semiconductor layer and the electrode is enlarged so that the electrons can be surely supplied to the plurality of nitride compound semiconductor layers.
The substrate side n-side electrode 271 can be formed by sputtering, E-beam evaporation or thermal deposition. In addition, the substrate side n-side electrode 271 contains any one selected from the group consisting of Ni, Au, Ag, Cr1 Ti, Pt, Pd, Rh, Ir, Al, Sn, In, Ta, Cu, Co, Fe, Ru, Zr, W and Mo, or a combination thereof, and serves as a reflecting film. The substrate side n-side electrode 271 is formed as a reflecting film to reflect light generated in the active layer, thereby emitting the generated light to the upper portion of the light emitting device.
As discussed earlier, in accordance with the Ill-nitride compound semiconductor light emitting device, the current can be uniformly diffused in the light emitting device. Furthermore, in accordance with the Ill-nitride compound semiconductor 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.
Although the preferred embodiments of the present invention have been described, it is understood that the present invention should not be limited to these preferred embodiments but various changes and modifications can be made by one skilled in the art within the spirit and scope of the present invention as hereinafter claimed.

Claims

[CLAIMS] [Claim 1]
A method of manufacturing a Ill-nitride compound semiconductor light emitting device including a plurality of Ill-nitride compound semiconductor layers which are grown on a substrate and which include an active layer for generating light by recombination of electron and hole, the method comprising: a first step for forming a groove in the substrate; a second step for forming the plurality of Ill-nitride compound semiconductor layers on the substrate with the groove formed therein; a third step for polishing the resulting structure so that the plurality of Ill-nitride compound semiconductor layers formed on the substrate can be exposed through the groove; and a fourth step for electrically connecting an electrode to the Ill-nitride compound semiconductor layer through the groove.
[Claim 2]
The method of claim 1 , prior to the third step, comprising the steps of: forming a light transmitting electrode on the plurality of Ill-nitride compound semiconductor layers; and forming a bonding pad to contact the light transmitting electrode.
[Claim 3]
A Ill-nitride compound semiconductor light emitting device, comprising: a first Ill-nitride compound semiconductor layer having first conductivity; a second Ill-nitride compound semiconductor layer having second conductivity different from the first conductivity; an active layer interposed between the first Ill-nitride compound semiconductor layer and the second Ill-nitride compound semiconductor layer, for generating light by recombination of electron and hole; a substrate positioned on the side of the first Ill-nitride compound semiconductor layer with regard to the active layer, a groove being formed in the substrate; a first electrode electrically connected to the first Ill-nitride compound semiconductor layer through the groove; a second electrode positioned on the side of the second Ill-nitride compound semiconductor layer with regard to the active layer, electrically connected to the second Ill-nitride compound semiconductor layer, and operated as a reflecting film; a sub-mount coupled to the second electrode; and a wire for electrically connecting the first electrode to the sub-mount.
[Claim 4]
The Ill-nitride compound semiconductor light emitting device of claim 3, comprising an opening formed at the upper portion of the groove along the first Ill-nitride compound semiconductor layer, the active layer and the second Ill-nitride compound semiconductor layer.
[Claim 5]
A method of manufacturing a Ill-nitride compound semiconductor light emitting device including a plurality of Ill-nitride compound semiconductor layers which are grown on a substrate and which include an active layer for generating light by recombination of electron and hole, the method comprising: a first step for forming the plurality of Ill-nitride compound semiconductor layers on the substrate; a second step for perforating a groove through the plurality of Ill-nitride compound semiconductor layers to reach the substrate; a third step for partially removing the substrate to expose the groove; and a fourth step for electrically connecting a first electrode to the Ill-nitride compound semiconductor layer through the groove from the substrate side.
[Claim 6]
The method of claim 5, wherein, in the second step, the groove is formed not to pass through the substrate.
[Claim 7]
The method of claim 5, prior to the fourth step, comprising a step for forming the first electrode through the groove from the side of the plurality of Ill-nitride compound semiconductor layers.
[Claim 8]
The method of claim 7, prior to the step for forming the first electrode , comprising a step for performing an etching process from the side of the plurality of Ill-nitride compound semiconductor layers to at least the active layer along the groove.
[Claim 9]
The method of claim 5, wherein, in the fourth step, the first electrode is formed on the whole surface of the substrate as a reflecting film.
[Claim 10] The method of claim 5, wherein the substrate is a sapphire substrate.
[Claim 11]
The method of claim 5, prior to the fourth step, comprising a step for forming a second electrode over the plurality of Ill-nitride compound semiconductor layers.
[Claim 12]
The method of claim 5, prior to the fourth step, comprising a step for simultaneously forming the first electrode and the second electrode from the side of the plurality of Ill-nitride compound semiconductor layers.
PCT/KR2006/005754 2006-02-01 2006-12-27 Iii-nitride semiconductor light emitting device and method of manufacturing the same WO2007089077A1 (en)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
KR10-2006-0009594 2006-02-01
KR20060009594A KR20070079139A (en) 2006-02-01 2006-02-01 Method of manufacturing iii-nitride semiconductor template and iii-nitride semiconductor light emitting device and method for manufacturing the same
KR1020060060872A KR100743471B1 (en) 2006-06-30 2006-06-30 Manufacturnig of iii-nitride semiconductor light emitting device
KR10-2006-0060869 2006-06-30
KR20060060869A KR20080002199A (en) 2006-06-30 2006-06-30 Iii-nitride semiconductor light emitting device
KR10-2006-0060872 2006-06-30

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20130130417A1 (en) * 2011-11-22 2013-05-23 Jar-Yu WU Manufacturing method of a light-emitting device
CN103548158A (en) * 2011-05-23 2014-01-29 并木精密宝石株式会社 Method for manufacturing light-emitting element, and light-emitting element

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR910020952A (en) * 1990-05-08 1991-12-20 김광호 Optoelectronic integrated circuit device and manufacturing method thereof
JP2004297095A (en) * 2001-11-19 2004-10-21 Sanyo Electric Co Ltd Process for fabricating compound semiconductor light emitting device
KR20050066358A (en) * 2003-12-26 2005-06-30 삼성전기주식회사 Nitride semiconductor light emitting device for flip chip and method of manufacturing the same
KR20050089120A (en) * 2004-03-03 2005-09-07 주식회사 이츠웰 Light emitting diode and manufacturing method of the same

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR910020952A (en) * 1990-05-08 1991-12-20 김광호 Optoelectronic integrated circuit device and manufacturing method thereof
JP2004297095A (en) * 2001-11-19 2004-10-21 Sanyo Electric Co Ltd Process for fabricating compound semiconductor light emitting device
KR20050066358A (en) * 2003-12-26 2005-06-30 삼성전기주식회사 Nitride semiconductor light emitting device for flip chip and method of manufacturing the same
KR20050089120A (en) * 2004-03-03 2005-09-07 주식회사 이츠웰 Light emitting diode and manufacturing method of the same

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103548158A (en) * 2011-05-23 2014-01-29 并木精密宝石株式会社 Method for manufacturing light-emitting element, and light-emitting element
EP2717335A1 (en) * 2011-05-23 2014-04-09 Namiki Seimitu Houseki Kabushiki Kaisha Method for manufacturing light-emitting element, and light-emitting element
JPWO2012160880A1 (en) * 2011-05-23 2014-07-31 並木精密宝石株式会社 LIGHT EMITTING DEVICE MANUFACTURING METHOD AND LIGHT EMITTING DEVICE
EP2717335A4 (en) * 2011-05-23 2014-12-03 Namiki Seimitu Houseki Kabushiki Kaisha Method for manufacturing light-emitting element, and light-emitting element
KR101516609B1 (en) * 2011-05-23 2015-05-04 나미키 세이미쓰 하우세키 가부시키가이샤 Method for manufacturing light-emitting element, and light-emitting element
US9065032B2 (en) 2011-05-23 2015-06-23 Namiki Seimitsu Houseki Kabushikikaisha Method for manufacturing light-emitting element, and light-emitting element
JP2015173293A (en) * 2011-05-23 2015-10-01 並木精密宝石株式会社 Light emitting element manufacturing method and light emitting element
US20130130417A1 (en) * 2011-11-22 2013-05-23 Jar-Yu WU Manufacturing method of a light-emitting device

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