Patent ID: 7049638

Claim:
A high-brightness GaN-based LED structure, comprising: a substrate made of a material selected from the group consisting of sapphire, 6H—SiC, 4H—SiC, Si, ZnO, GaAs, MgAl 2 O 4 , and an oxide monocrystalline having a lattice constant compatible with those of nitride semiconductors; a buffer layer made of Al a Ga b In 1-a-b N (0≦a,b<1, a+b≦1) having a specific composition located on top of an upper side of said substrate; an n-type contact layer made of a GaN-based material located on top of said buffer layer; an active layer made of InGaN located on top a part of said n-type contact layer; a negative electrode located on top of another part of said n-type contact layer not overlapping with said active layer; a p-type cladding layer made of a p-type GaN-based material located on top of said active layer; a p-type contact layer made of p-type GaN located on top of said p-type cladding layer; a masking buffer layer made of a two-element nitride having a thickness between 5 Å and 100 Å located on top of said p-type contact layer, said masking buffer layer comprising a plurality of randomly distributed clusters made of said two-element nitride; a p-type roughened contact layer made of Al e In f Ga 1-e-f N, (0≦e,f<1, e+f≦1) having a specific composition, said p-type roughened contact layer growing upward from a top surface of said p-type contact layer not covered by said masking buffer layer's clusters until said p-type roughened contact layer passes without covering said masking buffer layer's mask and reaches a thickness between 500 Å and 10,000 Å; a transparent conductive layer selected from the group consisting of a metallic conductive layer and a transparent oxide layer, located on top of a part of said p-type roughened contact layer's upper surface, said metallic conductive layer made of a material selected from the group consisting of Ni/Au alloy, Ni/Pt alloy, Ni/Pd alloy, Pd/Au alloy, Pt/Au alloy, Cr/Au alloy, Ni/Au/Be alloy, Ni/Cr/Au alloy, Ni/Pt/Au alloy, and Ni/Pd/Au alloy, and said transparent oxide layer made of a material selected from the group consisting of ITO, CTO, ZnO:Al, ZnGa 2 O 4 , SnO 2 :Sb, Ga 2 O 3 :Sn, AglnO 2 :Sn, In 2 O 3 :Zn, CuAlO 2 , LaCuOS, NiO, CuGaO 2 , and SrCu 2 O 2 ; and a positive electrode located on top of another part of said p-type roughened contact layer's upper surface not covered by said transparent conductive layer, made of a material selected from the group consisting of Ni/Au alloy, Ni/Pt alloy, Ni/Pd alloy, Ni/Co alloy, Pd/Au alloy, Pt/Au alloy, Ti/Au alloy, Cr/Au alloy, Sn/Au alloy, Ta/Au alloy, TiN, TiWN x (x≧0), and WSi y (y≧0).