Method for improving luminous efficiency of GaN based LED by using graphic underlay

Abstract

The invention provides a method which uses a graphic substrate to improve the illumination efficiency of a GaN-based efficiency, comprising the steps as follows: a silicon dioxide film is deposited on a sapphire substrate; a photoresist graphic array is optically etched; the photoresist graphic array is taken as a mask so as to etch the silicon dioxide film with the graphic structure; the silicon dioxide film with the graphic structure is taken as a mask so as to etch the sapphire substrate and the graphics is etched onto the sapphire substrate; the sapphire substrate is thoroughly cleaned so as to form a pyramid structure with triangular sections; a low-temperature nucleation layer grows on the graphic sapphire substrate; temperature is continuously increased on the low-temperature nucleation layer so as to grow an n-typed mixed GaN layer and an array structure which has low dislocation density and V-shaped holes on the surface; a multiple quantum well layer and a p-typed material layer required when the LED structure material grows continue to grow; furthermore, the final surface is led to still have the array structure with V-shaped holes.

Description

technical field [0001] The invention belongs to the technical field of semiconductors, in particular to a method for improving the luminous efficiency of a GaN-based LED by using a patterned substrate. The method can effectively improve the internal quantum luminous efficiency and light extraction efficiency of GaN-based LED materials. Background technique [0002] A light emitting diode (LED) is a junction electroluminescent semiconductor device that converts electrical signals into optical signals. Gallium Nitride (GaN)-based LED, as a solid-state light source, has been hailed as the second revolution in the history of human lighting after Edison invented the electric light for its advantages of high efficiency, long life, and environmental protection. and industry focus. However, GaN-based LEDs are currently entering the field of general lighting, and they still face many difficulties in terms of technology and cost. It is necessary to further improve the internal quant...

AI Technical Summary

Problems solved by technology

Due to the large lattice constant mismatch and thermal expansion coefficient difference between the sapphire substrate and the nitride epitaxial layer, there are large residual stress and many crystal defects in the nitride epitaxial layer, which affect the crystal quality of the material and limit the device. Further improvement in optoelectronic performance

At the same time, there is a large difference in refractive index between GaN and air, the light exit angle is very small, and most of it is totally reflected and returned to the inside of the LED device, which not only reduces the light extraction efficiency but also increases the difficulty of heat dissipation, affecting The stability of the LED device

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