Light emitting diode and method for manufacturing the same

Abstract

A light emitting diode and a method for manufacturing the same are disclosed. The light emitting diode comprises: a transparent substrate; a reflective layer located on a surface of the transparent substrate; a solder layer located on the other surface of the transparent substrate; a semiconductor epitaxial structure located on the solder layer, wherein the semiconductor epitaxial structure comprises a n-type contact layer, and the n-type contact layer can be a structure having a continuous flat surface, a structure having a continuous reticulate or bar surface, or a cylinder or prism structure having a discontinuous surface; and a transparent conductive layer located on the n-type contact layer of the semiconductor epitaxial structure.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a light emitting diode and a method for manufacturing the same, and more particularly, to a high-brightness light emitting diode manufactured by a wafer bonding technique. BACKGROUND OF THE INVENTION [0002] Referring to FIG. 1, FIG. 1 illustrates a cross-sectional view of a conventional light emitting diode. The light emitting diode comprises a substrate 100, a n-type semiconductor buffer layer 102, a n-type semiconductor contact layer 104, a n-type semiconductor cladding layer 106, an active layer 108, a p-type semiconductor cladding layer 110 and a p-type semiconductor contact layer 112 stacked in sequence. The light emitting diode further comprises a p-type contact pad 114 located on a portion of the p-type semiconductor contact layer 112, and a n-type contact pad 116 located on the exposed portion of the n-type semiconductor contact layer 104. [0003] The material of the substrate 100 of a conventional light emitting ...

AI Technical Summary

Benefits of technology

[0005] An objective of the present invention is to provide a light emitting diode having a transparent substrate, wherein a surface of the substrate having a reflective layer with high light reflection. Therefore, the loss of light absorbed by the substrate can be reduced, and the reuse of the photons can be provided, so as to increase the quantity of the photons extracted from lateral sides of the device.

[0006] Another objective of the present invention is to provide a light emitting diode, wherein a n-type contact pad of the light emitting diode is located on the front side of the device, so that the light emitting diode has a better current-spreading effect.

[0007] Still another objective of the present invention is to provide a light emitting diode, and a transparent conductive layer can be formed to cover the n-type contact layer after etching, thereby increasing light extraction efficiency and keeping a better current-spreading effect.

[0008] Further another objective of the present invention is to provide a method for manufacturing a light emitting diode, by stripping off a growth substrate that absorbs light; and bonding a semiconductor epitaxial structure of the light emitting diode to a transparent substrate by using a solder material and a wafer bonding step, after the semiconductor epitaxial structure is completed. Therefore, the loss of light absorbed by the substrate can be reduced greatly, and the step of bonding wafer does not need to consider the direction and disposition of bonding wafer, thus increasing the yield and reducing the production cost.

[0012] According to a preferred embodiment of the present invention, after the wafer bonding step is performed, the method further comprises etching a n-type semiconductor contact layer of the semiconductor structure to make the n-type semiconductor contact layer form a non-planar continuous structure or a discontinuous surface structure, so as to enhance current-spreading effect.

[0013] The loss of light intensity resulted from the absorbing of the substrate can be reduced greatly by removing the growth substrate. Besides, the yield can be increased and the production cost can be reduced by using a solder material to perform a wafer bonding step. Furthermore, the reflective layer on the transparent substrate can provide reuse of photons to increase the quantity of the photons extracted from the lateral side of the device. In addition, depositing a transparent conductive layer on the etched n-type semiconductor contact layer not only can increase light extraction efficiency, but also can maintain current-spreading effect.

Problems solved by technology

However, the U.S. Pat. No. 5,376,580 has a disadvantage of low yield caused by the need of considering the consistency of the lattice direction between the bonding wafers.

However, a disadvantage of the U.S. Pat. No. 6,258,699 is that: the light emitting diode wafer is easy to peel off after bonding, thus lowering the yield.

Images