The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 18, 2008
Filed:
Nov. 03, 2005
Liang-wen Wu, Banciao, TW;
Fen-ren Chien, Yonghe, TW;
Liang-Wen Wu, Banciao, TW;
Fen-Ren Chien, Yonghe, TW;
Formosa Epitaxy Incorporation, Taoyuan, TW;
Abstract
A GaN-based LED structure is provided so that the brightness and luminous efficiency of the GaN-based LED are enhanced effectively. The greatest difference between the GaN-based LEDs according to the invention and the prior arts lies in the addition of a masking buffer layer and a roughened contact layer on top of the masking buffer layer. The masking buffer layer contains randomly distributed clusters made of a group-IV nitride SiN(x,y≧1), a group-II nitride MgN(w,z≧1), or a group-III nitride AlInGaN (0≦s,t<1, s+t≦1) heavily doped with at least a group-II and group-IV element such as Mg and Si. The roughened contact layer, made of AlInGaN (0≦u,v<1, u+v≦1), starts from the top surface of an underlying second contact layer not covered by the masking buffer layer's clusters, and then grows upward until it passes (but does not cover) the clusters of the masking buffer layer for an appropriate distance. The total internal reflection that could have been resulted from the GaN-based LEDs' higher index of refraction than that of the atmosphere could be avoided.