Epitaxial growth method for improving electrostatic endurance capacity of GaN-based light-emitting diode (LED)

Abstract

The invention provides an epitaxial growth method for improving the electrostatic endurance capacity of a GaN-based light-emitting diode (LED). An LED epitaxial structure sequentially comprises a sapphire substrate, a low-temperature nucleating layer, a high-temperature GaN buffer layer, a high-temperature u-GaN layer, a composite n type GaN layer, a shallow quantum well structure (SW), a low-doped n-GaN electrostatic neutralization layer (EN), a multi-quantum well light-emitting layer structure (MQW), a low-temperature p type GaN layer, a p type Al GaN layer, a high-temperature p type GaN layer and a p type contact layer from bottom to top; the method comprises the steps of (1) inserting an n type Al GaN layer at the 1 / 3 thickness of the n type GaN layer; (2) inserting the n type GaN layer which is taken as the EN and has the specified thickness and concentration between the SW and the MQW; and (3) inserting the p type Al GaN layer with the specified thickness between the low-temperature p type GaN layer and the high-temperature p type GaN layer. After the epitaxial growth method is adopted, the electronic static discharge (ESD) endurance capacity is effectively improved; a 9mil*9mil chip adopts the conventional epitaxy technique, so that the average ESD stepping value is 200V; and after the epitaxy technique is adopted, the ESD stepping value is obviously increased to 385V.

Description

technical field [0001] The invention relates to the technical field of gallium nitride-based LED preparation, in particular to an epitaxial growth method for improving the electrostatic tolerance of GaN-based LEDs. Background technique [0002] Semiconductor light-emitting diodes (light-emission diodes, LED) are widely used in indicator lights, display screens, backlights and other fields due to their small size, low energy consumption, long life, environmental protection and durability, and LEDs in the field of white lighting Has shown great application potential. With the wide application of LEDs in the field of outdoor display and lighting, the chip itself is required to have more stringent electrostatic tolerance (ESD, Electro Static Discharge). [0003] At present, blue, green, and white LED chips mainly use GaN as the light-emitting matrix material, but due to the lack of GaN single crystal substrates, the GaN epitaxial layer mainly uses sapphire (Al 2 o 3 ) as the ...

AI Technical Summary

Problems solved by technology

However, due to the large lattice mismatch (>11%) and the large difference in thermal expansion coefficient between GaN and sapphire substrate, there are a large number of defects in the GaN epitaxial layer, and the defect density is as high as 1╳10 8 -1╳10 10 cm -2 , these defects appear as linear dislocations in the GaN epitaxial layer and can extend the entire epitaxial layer; some of the linear dislocations will develop into V-type defects after passing through the InGaN / GaN quantum well light-emitting epitaxial layer. The existence of these defects, It has a great adverse effect on the electrical properties such as leakage and ESD of LED chips

At the same time, since the p-type electrode and n-type electrode of the conventional GaN-based LED chip with sapphire as the substrate are located on the same plane, the current distribution is uneven, and the existing charge enrichment area also has a negative impact on the antistatic ability of the device.

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