Abstract:
Organic adhesive light-emitting device with ohmic metal bulge. The organic adhesive light-emitting device includes a conductive substrate, a light-emitting stack layer, a metal layer formed over the conductive substrate, a reflective layer formed over the light-emitting stack layer, and an organic adhesive layer having an ohmic metal bulge and an adhesive material around the ohmic metal bulge. The adhesive material bonds the metal layer and the reflective layer together, while the ohmic metal bulge forms ohmic contacts with the metal layer and the reflective layer. The configuration can simplify a light-emitting diode.

Description:
BACKGROUND OF INVENTION 
     1. Field of the Invention 
     The present invention provides a light-emitting element, and more particularly, an organic adhesive light-emitting device with an ohmic metal bulge. 
     2. Description of the Prior Art 
     The applications of light-emitting diodes (LED) are extensive and include such applications as optical display devices, traffic signals, data storing devices, communications devices, illumination devices, and medical apparatuses. An important issue is how to lower the manufacturing cost of LEDs. 
     A light-emitting diode and its related method of manufacture are disclosed in U.S. Pat. No. 6,682,950, in which a light-emitting diode layer is bonded to a transparent substrate by means of a transparent adhesive layer. Nevertheless, the prior art method, due to the non-conductivity of the transparent adhesive layer, while being suitable for use in diodes of which two electrodes are located at the same side, is not suitable for use in diodes of which electrodes are respectively located at the upper surface and lower surface of the diode. In addition, part of the diode stack layer needs to be removed by means of an etching process to produce two electrodes at the same side. In doing so, not only is material wasted, but also the complexity of the processes is increased. 
     SUMMARY OF INVENTION 
     It is therefore an object of the claimed invention to develop a light emitting diode having an organic adhesive layer with an ohmic metal bulge for sticking a conductive substrate and a light-emitting stack layer together, which forms ohmic contacts, so as to conduct current, and to simplify manufacturing processes and to reduce the cost of the diode. 
     Briefly described, the claimed invention discloses an organic adhesive light-emitting device with an ohmic metal bulge. The organic adhesive light-emitting device comprises a conductive substrate, a light-emitting stack layer, a metal layer formed over the conductive substrate, a reflective layer formed over the light-emitting stack layer, an organic adhesive layer with an ohmic metal bulge. The metal layer comprises an ohmic metal bulge for forming an ohmic contact between the metal layer and the reflective layer, and an adhesive material around the ohmic metal bulge for bonding the metal layer and the reflective layer together. 
     According to the claimed invention, the conductive substrate comprises at least one material selected from a material group consisting of GaP, GaAsP, AlGaAs, Si, Ge, and SiC, or other substitute materials. The adhesive material comprises at least one material selected from a material group consisting of PI, BCB, and PFCB, or other substitute materials. The ohmic metal bulge comprises at least one material selected from a material group consisting of In, Sn, Al, Au, Pt, Zn, Ge, Ag, Ti, Pb, Pd, Cu, AuBe, AuGe, Ni, PbSn, and AuZn, or other substitute materials. The reflective layer comprises at least one material selected from a material group consisting of In, Sn, Al, Au, Pt, Zn, Ge, Ag, Ti, Pb, Pd, Cu, AuBe, AuGe, Ni, Cr, PbSn, AuZn, and indium tin oxide, or other substitute materials. The metal layer comprises at least one material selected from a material group consisting of In, Sn, Al, Au, Pt, Zn, Ge, Ag, Ti, Pb, Pd, Cu, AuBe, AuGe, Ni, Cr, PbSn, and AuZn, or other substitute materials. The light-emitting layer comprises at least one material selected from a material group consisting of AlGaInP, GaN, InGaN, and AlInGaN, or other substitute materials. 
     These and other objects of the claimed invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  illustrates a schematic diagram of a present invention light-emitting diode having an organic adhesive layer with an ohmic metal bulge. 
         FIG. 2  illustrates a schematic diagram of a present invention light-emitting diode having an organic adhesive layer with an ohmic metal bulge. 
         FIG. 3  illustrates a schematic diagram of a present invention light-emitting diode having an organic adhesive layer with an ohmic metal bulge. 
     
    
    
     DETAILED DESCRIPTION 
     Please refer to  FIG. 1 , which illustrates an organic adhesive light-emitting device  1 . The organic adhesive light-emitting device  1  includes a first electrode  20 , a conductive substrate  10  formed over the first electrode  20 , a metal layer  11  formed over the conductive substrate  10 , and an organic adhesive layer  12  formed over the metal layer  11 . The organic adhesive layer  12  includes an ohmic metal bulge  121  and an adhesive material  122  around the ohmic metal bulge  121 . The adhesive material  122  adheres to a portion of the metal layer  11 , while the ohmic metal bulge  121  adheres to another portion of the metal layer  11  for forming an ohmic contact and a reflective layer  13  on the organic adhesive layer  12 . Furthermore, the adhesive material  122  adheres to a portion of the reflective layer  13 , while the ohmic metal bulge  121  adheres to: another portion of the reflective layer  13  for forming an ohmic contact, a transparent conductive layer  14  on the reflective layer  13 , a first contact layer  15  on the transparent conductive layer  14 , a first cladding layer  16  on the first contact layer  15 , a light-emitting layer  17  on the first cladding layer  16 , a second cladding layer  18  on the light-emitting layer  17 , a second contact layer  19  on the second cladding layer  18 , and a second electrode  21  on the second contact layer  19 . The reflective layer  13  can be eliminated because it is included solely to increase brightness. If the reflective layer  13  is eliminated, the metal layer  11  can be replaced with a metal reflective layer for reflecting. 
     Please refer to  FIG. 2 , which illustrates an organic adhesive light-emitting device  2 . The organic adhesive light-emitting device  2  includes a first electrode  220 , a conductive substrate  210  formed over the first electrode  220 , and an organic adhesive layer  211  formed over the conductive substrate  210 . The organic adhesive layer  211  includes an ohmic metal bulge  2111  and an adhesive material  2112  around the ohmic metal bulge  2111 . The adhesive material  2112  adheres to a portion of the conductive substrate  210 , while the ohmic metal bulge  2111  adheres to another portion of the conductive substrate  210  for forming an ohmic contact and a reflective layer  212  on the organic adhesive layer  211 . Furthermore, the adhesive material  2112  adheres to a portion of the reflective layer  212 , while the ohmic metal bulge  2111  adheres to: another portion of the reflective layer  212  for forming an ohmic contact, a transparent conductive layer  213  on the reflective layer  212 , a first contact layer  214  on the transparent conductive layer  213 , a first cladding layer  215  on the first contact layer  214 , a light-emitting layer  216  on the first cladding layer  215 , a second cladding layer  217  on the light-emitting layer  216 , a second contact layer  218  on the second cladding layer  217 , and a second electrode  221  on the second contact layer  218 . The reflective layer  212  can be replaced with a metal layer for forming an ohmic contact with the ohmic metal bulge  2111 . 
     Please refer to  FIG. 3 , which illustrates an organic adhesive light-emitting device  3 . The organic adhesive light-emitting device  3  includes a metal substrate  310 , and an organic adhesive layer  311  formed over the metal substrate  310 . The organic adhesive layer  311  includes an ohmic metal bulge  3111  and an adhesive material  3112  around the ohmic metal bulge  3111 . The adhesive material  3112  adheres to a portion of the metal substrate  310 , while the ohmic metal bulge  3111  adheres to another portion of the metal substrate  310  for forming an ohmic contact and a reflective layer  312  on the organic adhesive layer  311 . Furthermore, the adhesive material  3112  adheres to a portion of the reflective layer  312 , while the ohmic metal bulge  3111  adheres to: another portion of the reflective layer  312  for forming an ohmic contact, a transparent conductive layer  313  on the reflective layer  312 , a first contact layer  314  on the transparent conductive layer  313 , a first cladding layer  315  on the first contact layer  314 , a light-emitting layer  316  on the first cladding layer  315 , a second cladding layer  317  on the light-emitting layer  316 , a second contact layer  318  on the second cladding layer  317 , and a first electrode  319  on the second contact layer  318 . 
     In the above, the conductive substrate includes at least one material selected from a material group consisting of GaP, GaAsP, AlGaAs, Si, Ge, and SiC, or other substitute materials. The metal substrate includes at least one material selected from a material group consisting of Cu, Al, Mo, and MMC (metal matrix composite) carrier, or other substitute materials. The MMC carrier is a carrier with holes having been injected with a proper metal, so as to provide an adjustable heat conductive coefficient or a heat expansive coefficient. The adhesive material includes at least one material selected from a material group consisting of PI, BCB, and PFCB, or other substitute materials. The ohmic metal bulge includes at least one material selected from a material group consisting of In, Sn, Al, Au, Pt, Zn, Ge, Ag, Ti, Pb, Pd, Cu, AuBe, AuGe, Ni, PbSn, and AuZn, or other substitute materials. The reflective layer includes at least one material selected from a material group consisting of In, Sn, Al, Au, Pt, Zn, Ge, Ag, Ti, Pb, Pd, Cu, AuBe, AuGe, Ni, Cr, PbSn, AuZn, and indium tin oxide, or other substitute materials. The metal layer includes at least one material selected from a material group consisting of In, Sn, Al, Au, Pt, Zn, Ge, Ag, Ti, Pb, Pd, Cu, AuBe, AuGe, Ni, Cr, PbSn, and AuZn, or other substitute materials. The transparent conductive layer includes at least one material selected from a material group consisting of indium tin oxide, cadmium tin oxide, antimony tin oxide, zinc oxide, and zinc tin oxide, or other substitute materials. The first cladding layer includes at least one material selected from a material group consisting of AlGaInP, AlInP, AlN, GaN, AlGaN, InGaN, and AllnGaN, or other substitute materials. The light-emitting layer includes at least one material selected from a material group consisting of AlGaInP, GaN, InGaN, and AlInGaN, or other substitute materials. The second cladding layer includes at least one material selected from a material group consisting of AlGaInP, AlInP, AlN, GaN, AlGaN, InGaN, and AlInGaN, or other substitute materials. The second contact layer includes at least one material selected from a material group consisting of GaP, GaAs, GaAsP, InGaP, AlGaInP, AlGaAs, GaN, InGaN, and AlGaN, or other substitute materials. The first contact layer includes at least one material selected from a material group consisting of GaP, GaAs, GaAsP, InGaP, AlGaInP, AlGaAs, GaN, InGaN, and AlGaN, or other substitute materials. 
     Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.