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US 6,642,548 B1Granted
Light-emitting diodes with loop and strip electrodes and with wide medial sections
AssigneeEmcore Corporation
InventorsMichael G. Brown, Ivan Eliashevich, Louis A. Koszi
Life of this patent
Estimating the term…
Abstract
Light emitting diodes such as those formed from gallium nitride based semiconductors are provided with electrode and pad structures which facilitate current spreading. The LED may be formed as a die with a lower contact surface and a mesa projecting upwardly from the lower contact surface. An electrode on the lower contact surface may be in the form of a ring substantially encircling the mesa. In other arrangements, the pad and/or electrode on the lower contact surface is disposed in an indentation on one edge of the mesa whereas the pad on the top of the mesa is disposed adjacent the opposite edge of the mesa.
Claims31
A light-emitting diode comprising:
- (a) a stacked structure including a first region of a first conductivity type and a second region of a second conductivity type and a light-emitting p-n junction between said regions, said stacked structure defining a lower contact surface and a mesa projecting upwardly from said lower contact surface, said first-conductivity-type region being disposed in said mesa and defining a top surface of said mesa, said second-conductivity-type region defining said lower contact surface, said mesa having a near edge and a far edge parallel -to said near edge and remote from said near edge, said lower contact surface substantially surrounding said mesa;
- (b) a top electrode-pad unit including a transparent top electrode overlying at least a major portion of the top surface of said mesa, said transparent electrode being in contact with said first-type region at said top surface and a top pad overlying only a portion of said transparent electrode adjacent the middle of said far edge of said mesa;
- and
- (c) a lower electrode-pad unit including a lower electrode in contact with said lower contact surface and substantially surrounding said mesa and a lower pad in contact with said lower electrode adjacent said near edge of said mesa.
1 more element
A light-emitting diode comprising:
- (a) a stacked structure including a first region of a first conductivity type and a second region of a second conductivity type and a light-emitting p-n junction between said regions, said stacked structure defining a lower contact surface and a mesa projecting upwardly from said lower contact surface, said mesa having a near edge extending in a first horizontal direction, said first-conductivity-type region being disposed in said mesa and defining a top surface of said mesa, said second-conductivity-type region defining said lower contact surface, said lower contact surface including a near region adjacent said near edge of said mesa;
- (b) a lower electrode-pad unit including a lower electrode generally in the form of an elongated strip with its length extending in said first horizontal direction alongside said near edge of said mesa and overlying at least a portion of said lower contact surface, said lower electrode overlying said lower contact surface only in said near region;
- and
- (c) a top electrode-pad unit including a top pad, said top pad overlying only a portion of said mesa, said top pad having an extent in said first horizontal direction less than the length of said lower electrode.
1 more element
A light-emitting diode comprising:
- (a) a stacked structure including a first region of a first conductivity type and a second region of a second conductivity type and a light-emitting p-n junction between said regions, said stacked structure defining a lower contact surface and a mesa projecting upwardly from said lower contact surface, said first-conductivity-type region being disposed in said mesa and defining a top surface of said mesa, said second-conductivity-type region defining said lower contact surface;
- said mesa having a near edge and a far edge extending in a first horizontal direction on opposite sides of said mesa, said mesa having an indentation in said near edge adjacent the midpoint of said near edge extending downwardly from said top surface to said lower contact surface, said mesa having a medial plane midway between said near edge and said far edge, said mesa having a dimension in said first horizontal direction at said medial plane greater than the length of said near edge and greater than the length of said far edge;
- (b) a top electrode-pad unit including a top pad overlying only a portion of said top surface adjacent the midpoint of said far edge;
- and
- (c) a lower electrode-pad unit including a lower pad having an extent in said first horizontal direction shorter than said near edge, said lower pad being disposed at least partially in said indentation.
2 more elements
Dependencies are inferred from the claim text.