Light emitting diode device

Abstract

The present invention relates to a light emitting diode (LED) and a flip-chip packaged LED device. The present invention provides an LED device. The LED device is flipped on and connected electrically with a packaging substrate and thus forming the flip-chip packaged LED device. The LED device mainly has an Ohmic-contact layer and a planarized buffer layer between a second-type doping layer and a reflection layer. The Ohmic-contact layer improves the Ohmic-contact characteristics between the second-type doping layer and the reflection layer without affecting the light emitting efficiency of the LED device and the flip-chip packaged LED device. The planarized buffer layer id disposed between the Ohmic-contact layer and the reflection layer for smoothening the Ohmic-contact layer and hence enabling the reflection layer to adhere to the planarized buffer layer smoothly. Thereby, the reflection layer can have the effect of mirror reflection and the scattering phenomenon on the reflected light can be reduced as well.

1 . A light emitting diode device, comprising:
 a first-type doping layer;   a second-type doping layer;   a light emitting layer disposed between the first-type doping layer and the second-type doping layer;   an Ohmic-contact layer disposed on the second-type doping layer;   a stack of oxide layers comprising at least one metal oxide layer, disposed on the Ohmic-contact layer;   a first electrode electrically connected to the first-type doping layer;   a second electrode electrically connected to the Ohmic-contact layer; and   a metal layer disposed between the second electrode and the Ohmic-contact layer, wherein the second electrode is electrically connected to the Ohmic-contact layer through the metal layer,   wherein the stack of oxide layers at least comprises a first oxide layer having a higher light transmittance and a second oxide layer having a lower light transmittance, wherein the first oxide layer is disposed between the Ohmic-contact layer and the second oxide layer.   
     
     
         2 . The light emitting diode device of  claim 1 , wherein a light transmittance of the Ohmic-contact layer is greater than 90%. 
     
     
         3 . The light emitting diode device of  claim 1 , wherein the light transmittance of the first oxide layers is greater than 95%. 
     
     
         4 . The light emitting diode device of  claim 1 , wherein the light transmittance of the first oxide layers is greater than a light transmittance of the Ohmic-contact layer. 
     
     
         5 . The light emitting diode device of  claim 1 , wherein an electrical conductivity of the first oxide layer is lower than an electrical conductivity of the Ohmic-contact layer. 
     
     
         6 . The light emitting diode device of  claim 1  further comprising a cover layer disposed on the metal layer and extending to a sidewall of the metal layer. 
     
     
         7 . A light emitting diode device, comprising:
 a first-type doping layer;   a second-type doping layer;   a light emitting layer disposed between the first-type doping layer and the second-type doping layer;   an Ohmic-contact layer disposed on the second-type doping layer;   a stack of oxide layers comprising at least one metal oxide layer, disposed on the Ohmic-contact layer;   a first electrode electrically connected to the first-type doping layer;   a second electrode electrically connected to the Ohmic-contact layer; and   a metal layer disposed between the second electrode and the Ohmic-contact layer, wherein the second electrode is electrically connected to the Ohmic-contact layer through the metal layer,   wherein the stack of oxide layers at least comprises a first oxide layer having a lower refractivity and a second oxide layer having a higher refractivity, wherein the first oxide layer is disposed between the Ohmic-contact layer and the second oxide layer.   
     
     
         8 . The light emitting diode device of  claim 7 , wherein a light transmittance of the Ohmic-contact layer is greater than 90%. 
     
     
         9 . The light emitting diode device of  claim 7 , wherein a light transmittance of the first oxide layers is greater than 95%. 
     
     
         10 . The light emitting diode device of  claim 7 , wherein a light transmittance of one of the first oxide layers is higher than a light transmittance of the Ohmic-contact layer. 
     
     
         11 . The light emitting diode device of  claim 7 , wherein an electrical conductivity of the first oxide layer is lower than an electrical conductivity of the Ohmic-contact layer. 
     
     
         12 . The light emitting diode device of  claim 7  further comprising a cover layer disposed on the metal layer and extending to a sidewall of the metal layer. 
     
     
         13 . A light emitting diode device, comprising:
 a first-type doping layer;   a second-type doping layer;   a light emitting layer disposed between the first-type doping layer and the second-type doping layer;   an Ohmic-contact layer disposed on the second-type doping layer;   a stack of oxide layers comprising at least one metal oxide layer, disposed on the Ohmic-contact layer;   a first electrode electrically connected to the first-type doping layer;   a second electrode electrically connected to the Ohmic-contact layer; and   a metal reflection layer disposed between the second electrode and the Ohmic-contact layer, wherein the second electrode is electrically connected to the Ohmic-contact layer through the metal reflection layer,   wherein the stack of oxide layers at least comprises a first oxide layer having a lower electrical conductivity and a second oxide layer having a higher electrical conductivity, wherein the first oxide layer is disposed between the Ohmic-contact layer and the second oxide layer.   
     
     
         14 . The light emitting diode device of  claim 13 , wherein a light transmittance of the Ohmic-contact layer is greater than 90%. 
     
     
         15 . The light emitting diode device of  claim 13 , wherein a light transmittance of the first oxide layer is greater than 95%. 
     
     
         16 . The light emitting diode device of  claim 13 , wherein a light transmittance of the first oxide layer is higher than a light transmittance of the Ohmic-contact layer. 
     
     
         17 . The light emitting diode device of  claim 13  further comprising a cover layer disposed on the metal layer and extending to a sidewall of the metal layer. 
     
     
         18 . The light emitting diode device of  claim 13 , wherein a refractivity of the first oxide layer is lower than a refractivity of the Ohmic-contact layer.