Composite patterned substrate for LED growth, epitaxial wafer and preparation method

Abstract

The embodiment of the invention discloses a composite patterned substrate for LED growth, an epitaxial wafer and a preparation method. The composite patterned substrate comprises a sapphire substrate and a plurality of asymmetric convex structures located on the surface of one side of the sapphire substrate, the connecting lines of the top center points and the bottom center points of the asymmetric convex structures are not perpendicular to the surface of the sapphire substrate, and each asymmetric convex structure comprises a sapphire layer and a heterogeneous layer. The sapphire layer is located on one side of the surface of the sapphire substrate, and the heterogeneous layer is located on one side, deviating from the sapphire substrate, of the sapphire layer. According to the technical scheme provided by the embodiment of the invention, the plurality of asymmetrical bulge structures which are periodically arranged are formed on the c surface of the sapphire substrate, so that when the light rays touch the side edges, with the inclined angles, of the asymmetrical bulge structures, the light rays are more reflected, the randomization effect generated by multiple times of reflection and refraction of the light rays is enhanced, the light emitting probability is increased, and the light emitting efficiency is improved. Therefore, the light extraction efficiency is improved, and the energy utilization rate of the GaN-based LED is finally improved.

Description

technical field [0001] The embodiments of the present invention relate to the technical field of semiconductors, and in particular to a composite patterned substrate, an epitaxial wafer and a preparation method for LED growth. Background technique [0002] Compared with traditional incandescent lamps and fluorescent lamps, gallium nitride (GaN)-based light-emitting diodes (LEDs), as a new type of solid-state light source, have the advantages of low power consumption, long life, and high luminous efficiency, and play an important role in the fields of display and lighting. with increasing effect. Further improving the luminous efficiency (ie, external quantum efficiency) of GaN-based LEDs is a standard requirement for industry development. [0003] The current methods for improving the light extraction efficiency of GaN-based LEDs include: patterned sapphire substrates combined with GaN surface symmetric micro-nano structures, which are not conducive to lateral light extract...

AI Technical Summary

Problems solved by technology

For the symmetrical pattern structure, the existing patterned sapphire substrate combined with the asymmetric obtuse surface micro-nano structure is usually prepared by anisotropic wet etching process, and the anisotropic wet etching process has the following defects: The requirements for the substrate are high; the preparation process steps are cumbersome and complicated, and the environmental protection burden is large; the repeatability and controllability of the preparation process and the final microstructure are poor; it is impossible to prepare a composite material graphics substrate without an acid-resistant material layer

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