Light emitting diodes with spreading and improving light emitting area

Abstract

The present invention provides a light semiconductor device comprising a substrate and a first semiconductor structure on the substrate. A light emitting structure is on a first portion of the first semiconductor structure. A first contact structure is on a second portion of the first semiconductor structure. The second portion is separated from the first portion of the first semiconductor structure. The first contact structure has a first shape. A second semiconductor structure is on the light emitting structure. A transparent contact is on the second semiconductor structure and has a cut-off portion to expose the portion of second semiconductor structure and a second shape. A second contact structure is on the cut-off portion of the transparent contact. The second contact structure contacting the second semiconductor has a third shape. The second contact structure with the third shape is corresponded to both the transparent contact with the second shape and the first contact structure with the first shape whereby a relationship provides a plurality of current paths with substantially equal distances between the first contact structure and the second contact structure.

Description

BACKGROUND OF THE INVENTION[0001] 1. Field of the Invention[0002] The invention relates to light emitting diodes, and more particularly to light emitting diodes with spreading current and improving light emitting area.[0003] 2. Description of the Prior Art[0004] For photonic semiconductor device, light emitting diode (LED) may be the most commonly recognized because of its application to such a wide variety of products and applications such as scientific equipment, medical equipment and, perhaps most commonly, various consumer products in which LEDs form the light source for various signals, indicators, gauges, clocks, and many other familiar items. Semiconductor sources such as LEDs are particularly desirable as light output devices in such items because of their generally long lifetime, low power requirement, and their high reliability.[0005] Since early 1970s, gallium nitride (GaN)-based material has attracted attentions in applications to light emitters because of its wide bandg...

AI Technical Summary

Benefits of technology

[0008] One of the objectives of the present invention is to provide light emitting diodes with spreading current and improving light emitting area. Multitude of hollow patterns opened on the transparent contact can block the current shortcuts and further spread current and enhance the light emitting area.

[0009] Another one of the objectives of the present invention is to provide light emitting diodes with reducing density of surface state and leakage current. A passivation layer covering over surface can reduce the density of the surface state and lower leakage current.

[0010] Another one of the objectives of the present invention is to provide light emitting diodes with avoiding current crowding. The designed shapes of contacts and position arrangement for contacts can provide the current paths with substantially equal distance between contacts.

Problems solved by technology

However, it is still difficult to prepare a highly conductive p-type GaN layer.

Therefore, it is more difficult to make p-type ohmic contacts on and spread current in the p-type GaN layer.

However, the conductivity of the p-type GaN is still inferior to that of n-type one.

But the arrangement for the contacts has the disadvantage of current crowding happening between these electrodes.

As a result, the light emitting surface is not utilize efficiently, and the lifetimes of the transparent contact and the device are shorten by the current crowding.

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