Method for growing LED epitaxial structure

Abstract

The invention provides a method for growing an LED epitaxial structure, comprising a step 2 of growing a composite buffer layer including a low-temperature aluminum gallium nitride layer, an undoped first gallium nitride layer, an aluminum indium nitride layer, an undoped second gallium nitride layer, and an aluminum nitride layer which are successively grown from bottom to top. The growth of thelow-temperature aluminum gallium nitride layer can improve the lattice mismatch between a substrate and the gallium nitride layer. The growth of the undoped first gallium nitride layer can promote anincrease in size of the aluminum indium nitride particles in the aluminum indium nitride layer. The aluminum indium nitride layer also achieve good lattice matching with the undoped first gallium nitride layer and the undoped second gallium nitride layer, and promotes the release of stress at the bottom of the LED epitaxial structure. The growth of the aluminum nitride layer contributes to reducing the dislocation density in the LED epitaxial structure. The method, by means of the step 2, can improve the lattice mismatch, reduce the dislocation defect, and improve the light output power, the anti-aging ability and the antistatic capability of an LED device.

Description

technical field [0001] The invention relates to the technical field of LEDs, in particular to a method for growing an LED epitaxial structure. Background technique [0002] In the process of growing LED epitaxial structures on the substrate by using the metal chemical vapor deposition method MOCVD in the traditional LED epitaxial structure growth method, point dislocations, ductile dislocations and helical dislocations often occur due to the lattice mismatch between the substrate and GaN. Growth defects of dislocations. Generally speaking, the dislocation density of GaN grown by MOCVD method is 1×10 10 ~3×10 10 piece / m 2 , Dislocation defects severely damage the original crystal order of gallium nitride, thereby reducing the light output power of LED devices. For example, screw dislocations extend from the bottom layer of the LED epitaxial structure to the surface of the LED epitaxial structure, and pass through the LED light-emitting layer. Screw dislocations lead to no...

AI Technical Summary

Problems solved by technology

Generally speaking, the dislocation density of GaN grown by MOCVD method is 1×10 10 ~3×10 10 piece / m 2 , Dislocation defects severely damage the original crystal order of gallium nitride, thereby reducing the light output power of LED devices. For example, screw dislocations extend from the bottom layer of the LED epitaxial structure to the surface of the LED epitaxial structure, and pass through the LED light-emitting layer. Screw dislocations lead to non-luminescent radiation of holes and electrons in the LED light-emitting layer, which reduces the light output power of the LED device

In addition, dislocation defects will also increase the leakage channels of LED devices, which will accelerate the aging of LED devices due to the increase in leakage channels. Dislocation defects will also increase the breakdown path of LED devices and cause LED antistatic capabilities to weaken

At present, the LED market requires low driving voltage for LED chips, especially under high current density, the smaller the driving voltage and the higher the light efficiency, the better, but the current density is too high. The ability to expand the current is limited, and it is very easy to cause damage to the LED device, which eventually leads to a decrease in the anti-aging ability and anti-static ability of the LED device

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