Light-emitting diodes and method of manufacturing the same

Abstract

A surface-emitting AlGaInP LED is disclosed. The manufacturing method comprises the steps of: (i) forming a buffer layer, a first type of AlGaInP cladding layer, a AlGaInP active layer, a second type of AlGaInP cladding layer, and a second type of contact layer on a first type of GaAs substrate; (ii) forming a conductive transparent electrode; (iii) by using photolithography and etching techniques, a first photoresist layer with a hole is formed on the middle above the transparent electrode; (iv) etching the portion of the transparent electrode and the second type of GaAs layer not covered by the photoresist layer until the second type of AlGaInP cladding layer; (v) forming a metal layer on the hole being etched to form a Schottky barrier; (vi) thermal annealed to thicken an native oxide formed between the metal layer and the second type of AlGaInP cladding layer to increase the Schottky barrier level; (vii) removing the first photoresist layer, and coating a back electrode on an opposite surface of the first type of GaAs substrate; (viii) employing the photolithography and etching techniques and a mask being used in the photolithography of step (iii) to form a second photoresist layer with a hole at the center thereof; and (ix) forming a second metal over the metal layer being formed on the second type of AlGaInP cladding layer at step (v). The Schottky barrier and the native oxide serve as a current-blocking layer, and the luminance of a light-emitting diode is improved.