AlGaInP light-emitting diode having vertical structure with transparent multilayered reflective films
A method for manufacturing the AlGaInP LED having a vertical structure is provided, including: growing, epitaxially, a buffer layer, an n-type contact layer, an n-type textured layer, a confined layer, an active layer, a p-type confined layer and a p-type window layer in that order on a temporary substrate, to form a texturable epitaxial layer; forming a transparent conducting film with periodicity on the p-type window layer of the epitaxial layer, forming a regulated through-hole on the transparent conducting film, and filling the through-hole with a conducting material; forming a total-reflection metal layer on the transparent conducting film; bonding a permanent substrate with the texturable epitaxial layer via a bonding layer, and bring the total-reflection metal layer into contact with the bonding layer; removing the temporary substrate and the buffer layer; forming an n-type extension electrode on the exposed n-type contact layer; removing the n-type contact layer, and forming a pad on the n-type textured layer; and forming a p-type electrode on a back of the permanent substrate. The transparent multilayered film with periodicity provides a greater reflectivity difference and hence brings better results than the conventional reflector consisting of single-layered, or, non-periodic, transparent films; and light-emitting efficiency is enhanced.
1. An AlGaInP light-emitting diode (LED) having a vertical structure, comprising:
an epitaxial layer, comprising an n-type textured confined layer, an n-type contact layer, an active layer, a p-type confined layer and a p-type window layer that are stacked;
a stacked transparent layers having at least two periods, formed below the p-type window layer, wherein the stacked transparent layers comprises stacked transparent conducting layers and transparent dielectric layers;
a series of through-holes, distributed in the stacked transparent layers;
a total-reflection metal layer, formed below the stacked transparent layers, wherein the total-reflection metal layer fills up the through-holes;
a permanent substrate, bonded with the epitaxial layer via a metal bonding layer, wherein the total-reflection metal layer is in contact with the bonding layer;
an n-type extension electrode, in ohmic contact with the n-type contact layer; and
an n-type pad, formed on the n-type textured confined layer.
2. The AlGaInP LED having a vertical structure according to claim 1 , wherein the material of the permanent substrate is one or more selected from a group consisting of Ge, Si, GaP, GaAs, InP, Cu and Mo.
3. The AlGaInP LED having a vertical structure according to claim 1 , wherein the material of the transparent conducting layer is ITO, ZnO, AZO, ATO or FTO; and the material of the transparent dielectric layer is SiO 2 or Si 3 N 4 .
4. The AlGaInP LED having a vertical structure according to claim 1 , wherein a regulated through-hole is formed in the stacked transparent layers with periodicity.
5. The AlGaInP LED having a vertical structure according to claim 1 , wherein the material of the total-reflection metal layer is one or more selected from a group consisting of Ag, Al, Pt, Pd, Au, AuBe and AuZn.
6. The AlGaInP LED having a vertical structure according to claim 1 , wherein the p-type window layer has a carrier concentration larger than 1×10 18 cm −3 .
7. The AlGaInP LED having a vertical structure according to claim 1 , wherein the n-type contact layer has a carrier concentration larger than 1×10 18 cm −3 .
8. The AlGaInP LED having a vertical structure according to claim 1 , wherein the material of the n-type extension electrode is one or more selected from a group consisting of Ge, Au and Ni.