Increasing the brightness of III-nitride light emitting devices
First Claim
1. A light emitting structure comprising:
- a light emitting device comprising;
a base layer having a thickness exceeding about 3.5 micrometers formed above a sapphire substrate having an upper face misaligned at an angle of at least 0.05°
from a main crystal plane of the substrate; and
a III-Nitride light emitting region formed above the base layer;
wherein at least a portion of the base layer is doped with an n-type dopant.
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Accused Products
Abstract
LEDs employing a III-Nitride light emitting active region deposited on a base layer above a substrate show improved optical properties with the base layer grown on an intentionally misaligned substrate with a thickness greater than 3.5 μm. Improved brightness, improved quantum efficiency, and a reduction in the current at which maximum quantum efficiency occurs are among the improved optical properties resulting from use of a misaligned substrate and a thick base layer. Illustrative examples are given of misalignment angles in the range from 0.05° to 0.50°, and base layers in the range from 6.5 to 9.5 μm although larger values of both misalignment angle and base layer thickness can be used. In some cases, the use of thicker base layers provides sufficient structural support to allow the substrate to be removed from the device entirely.
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Citations
33 Claims
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1. A light emitting structure comprising:
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a light emitting device comprising;
a base layer having a thickness exceeding about 3.5 micrometers formed above a sapphire substrate having an upper face misaligned at an angle of at least 0.05°
from a main crystal plane of the substrate; and
a III-Nitride light emitting region formed above the base layer;
wherein at least a portion of the base layer is doped with an n-type dopant. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
a base layer having a thickness exceeding about 3.5 micrometers formed above a sapphire substrate having an upper face misaligned at an angle of at least 0.05°
from a main crystal plane of the substrate; and
a III-Nitride light emitting region formed above the base layer.
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24. A structure as in claim 1 wherein said main crystal plane is the r-plane.
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25. A light emitting structure comprising:
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a light emitting device comprising;
a base layer having a thickness exceeding about 5.5 micrometers formed above a substrate having an upper face misaligned at an angle of at least 0.05°
from a main crystal plane of the substrate; and
a III-Nitride light emitting region formed above the base layer. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33)
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Specification