Epitaxial wafer for light emitting diode, light emitting diode chip and methods for manufacturing the same
View Patent ↗An epitaxial wafer for a light emitting diode (LED) and a method for manufacturing the same are provided. The method comprises: providing a substrate; forming a first LED epitaxial structure on a first surface of the substrate, in which the first LED epitaxial structure comprises a first n-type semiconductor layer, a first light emitting layer, a first anti-diffusion layer between the first n-type semiconductor layer and the first light emitting layer, a first p-type semiconductor layer, and a second anti-diffusion layer between the first p-type semiconductor layer and the first light emitting layer; and forming a second LED epitaxial structure on a second surface of the substrate. An LED chip comprising the epitaxial wafer and a method for manufacturing the same are also provided.
1. An epitaxial wafer for a light emitting diode, said epitaxial wafer comprising:
a substrate;
a first LED epitaxial structure formed on a first surface of the substrate, in which the first LED epitaxial structure comprises:
a first n-type semiconductor layer doped with n-type impurities,
a first light emitting layer,
a first anti-diffusion layer between the first n-type semiconductor layer and the first light emitting layer, the first anti-diffusion layer being formed directly on the first n-type semiconductor layer,
a second anti-diffusion layer,
a first electron barrier layer directly on the second anti-diffusion layer, and
a first p-type semiconductor layer doped with p-type impurities on the first electron barrier layer, wherein the first and second anti-diffusion layers are adapted to block respectively the n-type and p-type impurities from diffusing to the first light emitting layer;
and
a second LED epitaxial structure formed on a second surface of the substrate.
2. The epitaxial wafer according to claim 1 , wherein the first LED epitaxial structure further comprises a first buffer layer formed between the first surface of the substrate and the first n-type semiconductor layer.
3. The epitaxial wafer according to claim 2 , wherein the first anti-diffusion layer and the second anti-diffusion layer comprise independently a nitride chosen from GaN, InGaN and AlGaInN.
4. The epitaxial wafer according to claim 1 , wherein the second LED epitaxial structure comprises:
a second buffer layer formed on the second surface of the substrate;
a second n-type semiconductor layer formed on the second buffer layer;
a second light emitting layer formed on the second n-type semiconductor layer; and
a second p-type semiconductor layer formed on the second light emitting layer.
5. The epitaxial wafer according to claim 1 , wherein the substrate is made of sapphire, and wherein the substrate has a thickness ranging from about 80 μm to about 200 μm.
6. The epitaxial wafer according to claim 1 , wherein the first anti-diffusion layer and the second anti-diffusion layer have independently a thickness ranging from about 2 nm to about 20 nm.
7. A light emitting diode (LED) chip, comprising:
a substrate;
a first LED epitaxial structure formed on a first surface of the substrate, wherein the first LED epitaxial structure comprises:
a first n-type semiconductor layer doped with n-type impurities,
a first light emitting layer,
a first anti-diffusion layer between the first n-type semiconductor layer and the first light emitting layer, the first anti-diffusion layer being formed directly on the first n-type semiconductor layer,
a second anti-diffusion layer,
a first electron barrier layer directly on the second anti-diffusion layer, and
a first p-type semiconductor layer doped with p-type impurities on the first electron barrier layer, wherein the first and second anti-diffusion layers are adapted to block respectively the n-type and p-type impurities from diffusing to the first light emitting layer;
a second LED epitaxial structure formed on a second surface of the substrate;
a first n-type electrode and a first p-type electrode formed on the first LED epitaxial structure;
a second n-type electrode and a second p-type electrode formed on the second LED epitaxial structure;
a circuit base board to which one of the first LED epitaxial structure and the second LED epitaxial structure is bonded; and
a heat conduction base board to which the other of the first LED epitaxial structure and the second LED epitaxial structure is bonded.
8. The LED chip according to claim 7 , wherein the first LED epitaxial structure emits blue light, and the second LED epitaxial structure emits yellow light; or
wherein the first LED epitaxial structure emits yellow light, and the second LED epitaxial structure emits blue light.
9. The LED chip according to claim 7 , wherein the substrate is made of sapphire, and wherein the substrate has a thickness ranging from about 80 μm to about 200 μm.
10. The LED chip according to claim 7 , wherein the first anti-diffusion layer and the second anti-diffusion layer comprise independently a nitride chosen from GaN, InGaN and AlGaInN.
11. The LED chip according to claim 7 , wherein the first anti-diffusion layer and the second anti-diffusion layer have independently a thickness ranging from about 2 nm to about 20 nm.