A light-emitting diode (LED) for both AlGaInP- and GaN-based materials needs a
good transparent current spreading layer to disseminate electrons or holes from
the electrode to the active layer. The present invention utilizes a conductive
and transparent ITO (Indium Tin Oxide) thin film with an ultra-thin (to minimize
the absorption) composite metallic layer to serve as a good ohmic contact and current
spreading layer. The present invention avoids the Schottky contact due to direct
deposition of ITO on the semiconductor. For AlGaInP materials, a thick GaP current
spreading layer is omitted by the present invention. For GaN-based LEDs with the
present invention, semi-transparent Ni/Au contact layer is avoided. Therefore,
the light extraction of LED can be dramatically improved by the present invention.
Holes may be etched into the semiconductor cladding layer forming a Photonic Band
Gap structure to improve LED light extraction.