GaN-based LED with dual reflecting layers

Abstract

The invention relates to a GaN-based LED with dual reflecting layers. The GaN-based LED comprises a substrate, an epitaxial layer, a current extension layer and a P electrode, wherein the epitaxial layer is formed on the substrate and comprises a P-type layer, a light-emitting region and an N-type layer; the current extension layer is formed on the P-type layer; and the P electrode is formed on the current extension layer. The GaN-based LED is characterized in that a reflecting structure is formed between the P electrode and the epitaxial layer and is composed of an annular reflecting layer and a metal reflecting layer, wherein the geometric center of the reflecting structure corresponds to the P electrode in the vertical direction, and the annular reflecting layer is formed between the current extension layer and the P-type layer; the metal reflecting layer is formed between the current extension layer and the P electrode; and a preset distance is reserved between the annular reflecting layer and the metal reflecting layer. According to the invention, the annular reflecting layer and the metal reflecting layer are additionally arranged between the epitaxial layer and the P electrode of the LED, so that light emitted from the light-emitting layer can be effectively taken out, the light absorption phenomenon of the P electrode is reduced, and therefore the light-emitting efficiency is increased.

Description

technical field [0001] The invention relates to a gallium nitride-based light-emitting diode, in particular to a gallium nitride-based high-brightness light-emitting diode with double reflection layers. Background technique [0002] At present, blue-green LEDs use GaN-based III-V compound semiconductor materials; due to the small hole concentration of the P-GaN layer of GaN-based LED epitaxial wafers, and the thickness of the P-type layer is very thin, most of the luminescence comes from The P-type layer leaks out, and the P-type layer inevitably absorbs light, resulting in low external quantum efficiency of the LED chip, which greatly reduces the luminous efficiency of the LED. Although the transmittance can be improved by using the ITO layer as the current spreading layer, the voltage of the LED is higher, and the lifetime is also affected. In addition, under the applied voltage, due to the uneven current diffusion, the current density in some areas is very high, which af...

AI Technical Summary

Problems solved by technology

Since the metal reflective layer 104 (usually Al or Ag material) has a reflective effect on light, the light emitted by the light-emitting layer is emitted and emitted from the side, as shown by light 1a; however, some light cannot or is difficult to pass through from the side Or above, as shown by light 1b, resulting in light loss, unable to effectively extract the light emitted by the light-emitting layer, which affects the luminous efficiency of the chip

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