LED (light-emitting diode) epitaxial wafer

Abstract

The invention provides an LED (light-emitting diode) epitaxial wafer which comprises a substrate, a gallium nitride nucleating layer, a gallium nitride buffer layer, an N-type gallium nitride layer, a P-type gallium nitride layer, a transparent conducting layer, a P-type electrode, an N-type electrode and an insert layer, wherein the substrate, the gallium nitride nucleating layer, the gallium nitride buffer layer, the N-type gallium nitride layer, the P-type gallium nitride layer, the transparent conducting layer, the P-type electrode and the N-type electrode are sequentially overlaid; the N-type electrode is formed on the etched N-type gallium nitride layer; the insert layer is arranged between the gallium nitride buffer layer and the N-type gallium nitride layer; the insert layer is an AlxGa1-xN layer or an InyAl1-yN layer or is formed in a mode that the AlxGa1-xN layer and the InyAl1-yN layer are overlaid; x is more than 0.1 and less than 1.0; and y is more than 0 and less than 0.25. For the LED epitaxial wafer provided by the invention, high-concentration two-dimension electron gas is generated on a heterogenous interface in the epitaxial wafer under the action of induction of great polarization difference mainly by utilizing the spontaneous polarization and piezoelectric polarization effects of a wurtzite III-Ns material; and due to high electron concentration and high mobility of the two-dimension electron gas, the transverse motion of electrons on the N-type gallium nitride layer can be improved, so that the injection efficiency of a carrier is improved, and thus, the light emitting efficiency of an LED is further improved.

Description

technical field [0001] The invention relates to the field of light emitting diodes, in particular to an LED epitaxial wafer. Background technique [0002] Currently, there are two main types of commercial substrates used for the epitaxial growth of gallium nitride-based blue and green LEDs (light-emitting diodes), namely sapphire substrates and silicon carbide substrates. However, because silicon carbide is expensive, 80% of the world's LED companies use sapphire substrates. Since sapphire is not conductive, the ohmic contact P-type electrode and N-type electrode formed on the sapphire substrate can only be on the same side of the epitaxial wafer surface, otherwise the current cannot be conducted and light cannot be emitted. This kind of LED epitaxial wafer has a mesa structure, the first mesa is a P-type contact surface, and the second mesa is an N-type contact surface formed by etching to N-type gallium nitride. The LED made by this process inevitably has the phenomenon ...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide an LED epitaxial wafer to solve technical problems such as low light extraction efficiency and short service life caused by uneven current expansion in the prior art.

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