Patent ID: 7998768

Claim:
A method for forming a light emitting diode, comprising: (a) growing epitaxially an epitaxial film over an epitaxial substrate; (b) roughening an upper surface of the epitaxial film; (c) forming a top electrode on the roughened upper surface of the epitaxial film; (d) detachably attaching a temporary substrate over the roughened upper surface of the epitaxial film that is formed with the top electrode, followed by removing the epitaxial substrate to expose a lower surface of the epitaxial film that is opposite to the roughened upper surface; (e) roughening the lower surface of the epitaxial film so that the roughened lower surface has a roughness with a height of not less than 300 nm and a plurality of peaks; (f) disposing the roughened lower surface of the epitaxial film on a reflective top surface of an electrically conductive permanent substrate so that the peaks of the roughened lower surface are in ohmic contact with the reflective top surface; (g) filling an optical adhesive in a gap between the roughened lower surface of the epitaxial film and the reflective top surface of the permanent substrate; and (h) after the step (g), removing the temporary substrate from the epitaxial film.