Manufacture method of GaN (gallium nitride)-based LED (light emitting diode) chip with roughened surface

Abstract

The invention discloses a manufacture method of a GaN (gallium nitride)-based LED (light emitting diode) chip with a roughened surface. The manufacture method comprises the steps that a metal organic chemical vapor deposition method is adopted, a low-temperature GaN buffer layer, an undoped GaN layer, a n-GaN layer, a multi-quantum well layer and a P-GaN layer are sequentially grown on a semiconductor substrate, and a GaN epitaxial wafer is formed; the GaN epitaxial wafer enters PECVD (plasma enhanced chemical vapor deposition) equipment so that sediments are in a nanometer island shape; the epitaxial wafer with the roughened surface is formed by using the nanometer island as an etching mask; one side of the GaN epitaxial wafer is subjected to etching, and a table surface is formed; an ITO (indium tin oxide) film is evaporated on the upper surface of the epitaxial wafer; and a P electrode is manufactured on P-GaN of the GaN epitaxial wafer, an N electrode is manufactured on n-GaN, and the device preparation is completed. The manufacture method has the advantages that the photoetching is not needed, the mask is automatically removed in the etching roughening process, the process is simple, the cost is low, the roughening effect is good, and the light extraction efficiency is high.

Description

Technical field [0001] The invention relates to the field of optoelectronic devices, in particular to a method for manufacturing a GaN-based LED chip with a roughened surface. Background technique [0002] There are two main factors in the luminous efficiency of light-emitting diodes (LEDs): the internal quantum effect and the external quantum effect of the device. At present, the internal quantum efficiency of a typical GaN blue LED can reach 80%. Therefore, it is unlikely that the internal quantum efficiency will be further improved significantly. Compared with the internal quantum efficiency, the external quantum efficiency of ordinary GaN-based LEDs is only a few percent. This is due to the large difference in refractive index between GaN and air. The critical angle of total reflection at the interface between GaN and air is 23 degrees. Only a small part of the light generated in the source area can be emitted into the air. In order to improve the light extraction efficienc...

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Problems solved by technology

Patent CN101702419 uses spin coating to coat Ni nanoparticles as a mask for dry etching, and patent CN101656284 uses ITO (indium tin oxide) particles as a mask for dry etching. These methods cannot accurately control the size of the mask and The disadvantage of uniformity leads to inconsistent effect of surface roughening of GaN sheet and uneven improvement of light extraction efficiency

Moreover, the removal of the mask requires the use of strong acids, which will oxidize the surface of the GaN material, resulting in an increase in the forward voltage of the device.

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