LED epitaxial structure and preparation method thereof

Abstract

The invention belongs to the technical field of semiconductors, and particularly relates to an LED epitaxial structure and a preparation method thereof. In the invention, a plurality of magnesium nitride compound nucleation structures are inserted between an electron blocking layer and the last barrier layer; by taking the nucleation structures as the core, a plurality of island structures are grown to reduce the total reflection of light at the interface between the electron blocking layer and the last barrier layer, so that the light emitted from a multi-quantum well light emitting layer enters the electron blocking layer more and the light emitting efficiency of the LED epitaxial structure is further improved; and the island structures are filled through the electron blocking layer, andthen the LED epitaxial structure with a flat surface is obtained.

Description

technical field [0001] The invention belongs to the technical field of semiconductors, and in particular relates to an LED epitaxial structure and a preparation method thereof. Background technique [0002] LED is a semiconductor solid-state light-emitting device, which uses a semiconductor P-N junction as a light-emitting structure. Gallium nitride is currently regarded as the third-generation semiconductor material, and gallium nitride-based light-emitting diodes with InGaN / GaN active regions are regarded as the most advanced Potential light source. [0003] See attached figure 1 At present, the GaN-based blue LED epitaxial structure generally includes a substrate, a buffer layer, a first semiconductor layer, a multi-quantum well light-emitting layer, a final barrier layer, an electron blocking layer, and a second semiconductor layer. The multi-quantum well light-emitting layer is generally InGaN / GaN superlattice structure, the electron blocking layer is a P-type AlGaN ...

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Problems solved by technology

[0003] See attached figure 1 At present, the GaN-based blue LED epitaxial structure generally includes a substrate, a buffer layer, a first semiconductor layer, a multi-quantum well light-emitting layer, a final barrier layer, an electron blocking layer, and a second semiconductor layer. The multi-quantum well light-emitting layer is generally InGaN / GaN superlattice structure, the electron blocking layer is a P-type AlGaN structure, but because the refractive index of AlGaN material is lower than that of GaN and InGaN, the light emitted in the multi-quantum well light-emitting layer is easy to pass through the interface between the final barrier layer and the electron blocking layer. Total reflection occurs at the place, resulting in poor light extraction efficiency

[0004] In the prior art, in order to improve the light extraction efficiency, the surface roughening technology of the P-type layer is also used. Although this technology can improve the light extraction efficiency to a certain extent, it cannot improve the light emission caused by the phenomenon at the interface between the final barrier layer and the electron blocking layer. The loss of extraction efficiency, and because the surface roughening technology is prone to uneven roughening, the yield rate is poor and the color difference between the P electrode and the N electrode of the LED is caused, which makes it difficult to identify the automatic wire bonding machine

[0005] Another common technology to improve the light extraction efficiency is to use a patterned substrate. Although this technology can improve the light extraction efficiency to a certain extent without affecting the wiring, it cannot completely improve the interface between the final barrier layer and the electron blocking layer. The loss of light extraction efficiency caused by total reflection phenomenon

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