Optimized light-emitting diode (LED) chip patterned substrate and LED chip

Abstract

The invention discloses an optimized light-emitting diode (LED) chip patterned substrate. A Pattern of the LED chip patterned substrate is composed of a plurality of regular hexagonal pyramids with the same shape, the regular hexagonal pyramids are arranged on the surface of the LED chip patterned substrate, dip angles Alpha of the regular hexagonal pyramids are 55 degrees to 60 degrees, and edge distances between regular hexagonal pyramids next to each other are 1.0-1.2 Mum. Compared with the prior art, the LED chip patterned substrate has the advantages that luminous efficiency of the patterned substrate LED chip is greater than that of a ordinary patterned substrate LED chip, available effective light rays are increased greatly, and external quantum efficiency of the LED chip is improved. What is more, the pattern of regular hexagonal pyramids is coincident with a lattice structure of GaN, so the LED chip patterned substrate is beneficial for epitaxial growth of high quality GaN crystals, quality of epitaxy is further improved, and accordingly internal quantum efficiency of the LED chip is improved.

Description

technical field [0001] The invention relates to an LED chip, in particular to an optimized LED patterned substrate and an LED chip. Background technique [0002] The light extraction efficiency of LED depends on internal quantum efficiency and external quantum efficiency. On the one hand, due to the large difference in the lattice constant and thermal expansion coefficient of GaN and sapphire substrates, the crystals of GaN thin films have a density of 10 9 -10 12 cm -2 traversing dislocations, which adversely affect the internal quantum efficiency of GaN-based LEDs. However, with the continuous optimization of GaN epitaxial growth technology, the epitaxial quality of GaN has improved, and the internal quantum efficiency of LEDs has reached more than 90%. On the other hand, GaN has a higher refractive index (n=2.45), and the critical angle [θ c = sin -1 (n air / n GaN )] is only 24.6°, resulting in serious total reflection between the LED chip and the air, and it is ...

AI Technical Summary

Problems solved by technology

[0004] Even though patterned substrates have greatly improved the light extraction efficiency of LEDs, there are still few studies on regular hexagonal pyramid patterns. For the patterned substrates with regular hexagonal pyramids as the basic pattern, there is still no research result that can clearly point out the optimal pattern inclination angle. , side length, pattern density and other parameters, the application of regular hexagonal pyramid pattern substrate pattern lacks a set of systematic design indicators

In addition, in terms of pattern size optimization, the trade-off between size reduction and damage to GaN growth quality is solved, and better epitaxy quality is ensured under the premise of improving light extraction efficiency, so as to truly improve LED performance. still to be studied

Images