Preparation method of P electrode of light-emitting diode chip with vertical structure

Abstract

The invention provides a preparation method of a P electrode of a light-emitting diode chip with a vertical structure, and belongs to the field of light-emitting diodes. The method comprises the steps of providing a light-emitting diode epitaxial wafer, wherein the light-emitting diode epitaxial wafer comprises a substrate, and a buffer layer, an undoped GaN layer, an N-type GaN layer, a multi-quantum well layer, an electron barrier layer, a P-type GaN layer and a P-type ohmic contact layer which are stacked on the substrate in sequence, wherein a contact layer electrode is grown on the P-type ohmic contact layer, thermal annealing treatment is conducted on the contact layer electrode, and the contact layer electrode comprises a Ni layer; and a first reflecting layer electrode is grown on the contact layer electrode, thermal annealing treatment is conducted on the first reflecting layer electrode, the first reflecting layer electrode comprises a first Ag layer, the annealing time of the first reflecting layer electrode is shorter than that of the contact layer electrode, and the annealing temperature of the first reflecting layer electrode is lower than that of the contact layer electrode. According to the invention, the P electrode with high reflectivity and low contact resistivity can be obtained.

Description

technical field [0001] The present disclosure relates to the field of light emitting diodes, and in particular, to a method for preparing a P electrode of a vertical structure light emitting diode chip. Background technique [0002] The two electrodes of the vertical structure LED (Light Emitting Diode, light emitting diode) chip are respectively on two sides of the LED epitaxial layer. At present, a key difficulty of vertical structure LEDs is the p-type ohmic contact. Taking GaN-based vertical structure LEDs as an example, on the one hand, due to the high activation energy of Mg, it is difficult to obtain p-GaN with high hole concentration, on the other hand, The p-GaN electrode of a GaN-based LED with a vertical structure serves as both an ohmic contact electrode and an optical mirror, which puts forward very high requirements on the material system of the electrode. Therefore, p-GaN electrodes with good ohmic contact and high reflectivity are crucial for GaN-based LEDs ...

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Problems solved by technology

[0004] In the process of realizing the present disclosure, the inventors found that the related technology has at least the following problems: the high temperature in the annealing process will lead to the aggregation of Ag and the mixing of Ag and other metals will cause the electrode reflectivity of the p-GaN electrode to decrease, thereby affecting the electrode reflectivity of the p-GaN electrode. optical performance

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