Light-emitting diode (LED) epitaxial structure and fabrication method thereof

The invention provides a light-emitting diode (LED) epitaxial structure and a fabrication method thereof. The LED epitaxial structure sequentially comprises a substrate, an N-type GaN layer, a multiple quantum well (MQW) active layer, an electron blocking layer and a P-type GaN layer from bottom to top, wherein a polarization doped barrier layer is further grown between the MQW active layer and the electron blocking layer and is a AlxGaN barrier layer, and the molar content of Al in the AlxGaN barrier layer is gradually reduced from a lower surface in contact with the MQW active layer to an upper surface in contact with the electron blocking layer. In the LED epitaxial structure, the novel polarization doped barrier replaces a traditional low-temperature u-AlGaN layer and is the AlxGaN barrier layer, the molar content of the Al in the AlxGaN barrier layer is gradually reduced from the lower surface in contact with the MQW active layer to the upper surface in contact with the electron blocking layer, therefore, light absorption is reduced, emergent light is promoted, meanwhile, single furnace time is reduced, and yield is enhanced; moreover, the polarization doped barrier forms an energy level reduced gradually, hole injection is promoted, and combination efficiency is improved.