LIGHT EMITTING DEVICE HAVING MgO PYRAMID STRUCTURE AND METHOD FOR FABRICATING THE SAME

Abstract

A method for fabricating a light emitting device, the method including forming a semiconductor stack structure including a first semiconductor layer, a second semiconductor layer, and an active layer disposed therebetween, on a substrate, and forming a refractive index adjustment layer on the first semiconductor layer. The refractive index of the refractive index adjustment layer is smaller than the refractive index of the first semiconductor layer. Refractive indices of the first semiconductor layer and each layer disposed on the first semiconductor layer sequentially decrease in a direction extending away from the first semiconductor layer.

What is claimed is: 
     
         1 . A method for fabricating a light emitting device, the method comprising:
 forming a semiconductor stack structure comprising a first semiconductor layer, a second semiconductor layer, and an active layer disposed therebetween, on a substrate; and   forming a refractive index adjustment layer on the first semiconductor layer,   wherein the refractive index of the refractive index adjustment layer is smaller than the refractive index of the first semiconductor layer, and   wherein refractive indices of the first semiconductor layer and each layer disposed on the first semiconductor layer sequentially decrease in a direction extending away from the first semiconductor layer.   
     
     
         2 . The method of  claim 1 , wherein the refractive index adjustment layer comprises:
 a first refractive index adjustment layer formed on the first semiconductor layer, the first refractive index adjustment layer comprising a refractive index smaller than the refractive index of the first semiconductor layer; and   a second refractive index adjustment layer formed on the first refractive index adjustment layer, the second refractive index adjustment layer comprising a refractive index smaller than the refractive index of the first refractive index adjustment layer,   wherein the second refractive index adjustment layer comprises a pyramid structure.   
     
     
         3 . The method of  claim 1 , wherein the substrate is conductive. 
     
     
         4 . The method of  claim 1 , wherein the first semiconductor layer comprises a nitride-based semiconductor layer, and the first refractive index adjustment layer comprises a ZnO-based semiconductor oxide. 
     
     
         5 . The method of  claim 1 , wherein the second refractive index adjustment layer comprises a ternary MgO-based compound, or a multicomponent MgO-based compound comprising MgO and at least two other elements. 
     
     
         6 . The method of  claim 5 , wherein the ternary MgO-based compound comprises Mg x Be 1-x O, Mg x Ca 1-x O, Mg x Sr 1-x O, or Mg x Ba 1-x O, and wherein the multicomponent MgO-based compound comprises two or more of Be, Ca, Sr, and Ba. 
     
     
         7 . The method of  claim 5 , wherein the ternary MgO-based compound or the multicomponent MgO-based compound is doped with an impurity, the impurity comprising at least one of B, In, Zn, Tl, Al, Sn, Ga, Te, Si, C, Ge, N, P, As, Sb, Bi, S, Se, Br, I, Ti, and an oxide thereof 
     
     
         8 . The method of  claim 1 , wherein the first refractive index adjustment layer comprises at least one of ZnO, Al-doped ZnO, In-doped ZnO, Ga-doped ZnO, ZrO 2 , TiO 2 , SiO 2 , SiO, Al 2 O 3 , CuO x , and indium tin oxide (ITO).