GaN-based LED preparation method based on regional laser lift-off and chemical corrosion

Abstract

The invention discloses a GaN-based LED preparation method based on regional laser lift-off and chemical corrosion. The method includes the following steps: manufacturing an ohmic contact layer and a metal layer sequentially on a p-type GaN and manufacturing a new support substrate; carrying out laser groove cutting on a polished sapphire surface according to the size of an LED chip, wherein the groove depth reaches the new support substrate; carrying out regional laser lift-off on a sapphire sample on which a mask plate is placed; placing the sample in a corrosion solution which enters the GaN layer, which bounders with the sapphire substrate, through cut grooves and corrodes the GaN layer in a side direction so that the sapphire substrate is removed completely finally, and coarsening the surface of the GaN; manufacturing an n-type electrode and a passivation layer on the surface of the GaN, the substrate of which is removed, so that an LED chip of a vertical structure is formed. The method prevents damages on a GaN epitaxial wafer because of unevenness of laser spots and overlapping of the laser spots during traditional laser lift-off and prevents a defect that a traditional corrosion technology requires a thicker GaN thickness at the same time.

Description

technical field [0001] The invention relates to a method for preparing a GaN-based LED, in particular to a method for preparing an LED chip based on laser stripping and chemical corrosion. Background technique [0002] Due to the small lattice mismatch between the sapphire substrate and the GaN material, and its low price, it is currently the main substrate for growing GaN-based epitaxial layers. However, due to its poor conductivity, traditional GaN-based LEDs have the same-side electrode structure. The electrodes on the same side not only increase the current flow path and operating voltage, but also lead to the current congestion effect and increase the heat generation of the device. However, the low thermal conductivity of the sapphire substrate prevents the internal heat of the device from being dissipated in time, which leads to problems such as a decrease in the luminous power of the LED device and a shortened lifespan. Therefore, the traditional structure LED is no...

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Problems solved by technology

[0004] In order to solve the above-mentioned problem of material quality degradation of the GaN-based epitaxial film due to uneven laser spot energy during the laser lift-off process, and to avoid the requirement of chemical corrosion on the thickness of the GaN material, so as not to damage the quality of the GaN-based epitaxial film after removing the sapphire substrate, To improve the yield, the present invention aims to propose a GaN-based LED preparation method based on regional laser lift-off and chemical etching, and use the technology of regional laser lift-off and chemical etching to prepare GaN-based LEDs with vertical structures

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