Patent ID: 7148519

Claim:
A GaN 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 that of nitrides; a double buffer layer, located on top of said substrate, further comprising: a first buffer layer, made of Al 1-x-y Ga x In y N 0≦X<1, 0≦Y<1, and X+Y≦1, located on top of said substrate, and a second buffer layer, made of SiN, located on top of said first buffer layer; an n-type GaN layer, located on top of said double buffer layer; a short period superlattice contacting layer, located on top of said n-type GaN layer, further comprising: a plurality of foundation layers, located on top of said n-type GaN layer, each of said foundation layers further comprising: a first base layer, made of heavily silicon doped n-type Al 1-x-y Ga x In y N (n ++ -Al 1-x-y Ga x In y N), where 0≦X<1, 0≦Y<1, X+Y≦1, and a second base layer, located on top of said first base layer, made of undoped In 1-u Ga u N where 0≦u<1; an active layer, made of InGaN, located on top of said short period superlattice contacting layer; a p-type shielding layer, made of Mg-doped Al 1-x-y Ga x In y N, where 0≦X<1, 0≦Y<1 and X+Y≦1, located on top of said active layer; and a contacting layer, made of p-type Mg-doped Al 1-x-y Ga x In y N, where 0≦X<1, 0≦Y<1 and X+Y≦1, located on top of said p-type shielding layer.