LED Epitaxial Structure and Fabrication Method Thereof

A fabrication method of an LED epitaxial structure, comprising:

• providing a substrate;
• forming a GaN nucleating layer epitaxied over the substrate;
• forming a superlattice buffer layer comprising a plurality pairs of AlGaN/n-GaN structure layers over the GaN nucleating layer;
• forming an n-GaN layer epitaxied over the AlGaN/n-GaN superlattice buffer layer;
• forming a MQW light-emitting layer epitaxied over the N-type GaN layer, forming a p-GaN layer epitaxied over the MQW light-emitting layer, and forming a p-type contact layer epitaxied over the p-GaN layer;
• wherein Al(n) represents Al composition value of an nth AlGaN/n-GaN superlattice buffer layer pair;
• N(n) represents n-type impurity concentration value of the nth AlGaN/n-GaN superlattice buffer layer pair;
• a variation trend of Al(n) is from gradual increase to gradual decrease, and a variation trend of N(n) is from gradual increase to gradual decrease.

A light-emitting system comprising a plurality of LED epitaxial structures, each epitaxial structure including, from bottom to up, a substrate;

• a GaN nucleating layer;
• a superlattice buffer layer comprising a plurality pairs of alternately stacked AlGaN/n-GaN structures;
• an n-GaN layer;
• a MQW light-emitting layer, a p-GaN layer and a p-type contact layer;
• wherein Al(n) represents Al composition value of an nth AlGaN/n-GaN superlattice buffer layer pair;
• N(n) represents n-type impurity concentration value of the nth AlGaN/n-GaN superlattice buffer layer pair;
• a variation trend of Al(n) is from gradual increase to gradual decrease, and a variation trend of N(n) is from gradual increase to gradual decrease.