Fabrication of p‐pad‐up GaN‐based thin‐film light‐emitting diodes with electroplated metallic substrates

A novel method has been developed to fabricate p‐pad‐up GaN‐based thin‐film light‐emitting diodes (TF‐LEDs) with electroplated metallic substrates. First, a Ni/Ag/Ni/Au mirror severed as p‐contact is totally covered by an insulating SiN x layer, which separates n‐contact from the p‐contact. Then, a copper layer connected with the n‐contact was electroplated to a thickness of about 120 μm as a metallic substrate for the light‐emitting diode epitaxial wafer. After removal of the original sapphire substrate with an excimer laser, the exposed GaN layers were selectively etched to the p‐contact. Finally, a Cr/Pt/Au multilayer was deposited onto the p‐contact to complete the whole p‐pad‐up TF‐LED structure. The p‐pad‐up TF‐LEDs exhibit superior electrical and optical properties at high driven current densities.