Light emitting diode and method for manufacturing the same
View Patent ↗A light emitting diode includes a substrate, a first-type semiconductor layer, a nanorod layer and a transparent planar layer. The first-type semiconductor layer is disposed over the substrate. The nanorod layer is formed on the first-type semiconductor layer. The nanorod layer includes a plurality of nanorods and each of the nanorods has a quantum well structure and a second-type semiconductor layer. The quantum well structure is in contact with the first-type semiconductor layer, and the second-type semiconductor layer is formed on the quantum well structure. The transparent planar layer is filled between the nanorods. A surface of the second-type semiconductor layer is exposed out of the transparent planar layer.
1. A method for manufacturing a light emitting diode, comprising:
providing a substrate;
forming a first-type semiconductor layer on the substrate;
forming a quantum well layer on the first-type semiconductor layer;
forming a second-type semiconductor layer on the quantum well layer;
patterning the quantum well layer and the second-type semiconductor layer to form a plurality of nanorods;
filling a transparent planar material into a space between the nanorods, wherein a top portion of each of the nanorods is exposed out of the transparent planar material;
removing a portion of the second-type semiconductor layer, a part of the nanorods, a portion of the first-type semiconductor layer and a portion of the transparent planar material to form a trapezoid sidewall structure such that a portion of the first-type semiconductor layer is exposed; and
forming a transparent electrode layer to cover the transparent planar material and the top portion.
2. The method according to claim 1 , wherein the step of patterning the quantum well layer and the second-type semiconductor layer comprising:
forming a quantum well structure in each of the nanorods, wherein each of the quantum well structure has a width W and a height H, and the width W and the height H satisfy the following formula (I):
0.5 H≦W<10 H formula (I).
3. The method according to claim 2 , wherein the step of patterning the quantum well layer and the second-type semiconductor layer comprising:
forming a patterned hard mask on the second-type semiconductor layer, wherein a portion of the second-type semiconductor layer is exposed;
removing the exposed portion of the second-type semiconductor layer and the quantum well layer there under to form the nanorods; and
removing the patterned hard mask on the nanorods.
4. The method according to claim 3 , wherein the step of filing the transparent planar material comprises filling benzocyclobutene into the space between the nanorods.
5. The method according to claim 4 , further comprising a step of forming a first connecting pad and a second connecting pad respectively on the transparent electrode layer and the exposed portion of the first-type semiconductor layer.
6. The method according to claim 5 , wherein the first-type semiconductor layer comprises N-type gallium nitride, and the second-type semiconductor layer comprises P-type gallium nitride.
7. The method according to claim 6 , further comprising a step of forming an undoped gallium nitride layer on the substrate prior to forming the first-type semiconductor layer.