Patent ID: 7087922

Claim:
A light-emitting diode structure, comprising: a substrate made of a material selected from a group consisting of Sapphire, 6H-Sic, 4H-Sic, ZnO, GaAs, MgAl 2 O 4 , and a single crystal oxide with a lattice constant close to that of a nitride semiconductor; a buffer layer formed on said substrate, and made of Al 1-a-b Ga a In b N, wherein 0≦a, b<1, and a+b≦1; an n-type gallium-nitride contact layer formed on said buffer layer, said n-type gallium-nitride contact layer having 900–1200° C. growth temperature, and 2–5 μm thickness; a light-emitting stack layer formed on said n-type gallium-nitride contact layer, and made of Al 1-x-y Ga x In y N with 700–900° C. growth temperature, wherein 0<x, y<1, and x+y≦1; a p-type gallium-nitride contact layer formed on said light-emitting stack layer, said p-type gallium-nitride contact layer having 900–1200° C. growth temperature, and thickness less than 5000 Å; a digital penetration layer formed on said p-type gallium-nitride contact layer; a transparent conductive layer formed on said digital penetration layer, and made of a material selected from a group consisting of Ni/Au, Ni/Pt, Ni/Pd, Pd/Au, Pt/Au, Cr/Au, Ni/AuBe, Ni/Cr/Au, Ni/Pt/Au, and Ni/Pd/Au; a first ohmic contact electrode formed over a portion of said digital penetration layer not covered by said transparent conductive layer to serve as a p-type ohmic contact, said first ohmic contact electrode being made of a material selected from a 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); and a second ohmic contact electrode formed over a portion of said n-type gallium-nitride layer to serve as an n-type ohmic contact, said second ohmic contact electrode being made of a material selected from a group consisting of Ti/Al alloy, Ti/Al/Ti/Au alloy, Ti/Al/Ni/Au alloy, Ti/Al/Pt/Au alloy, Ti/Au alloy, and Cr/Au alloy.