US-12622108-B2 - Interconnect structures for improved light-emitting diode chip performance

US12622108B2US 12622108 B2US12622108 B2US 12622108B2US-12622108-B2

Abstract

Solid-state lighting devices including light-emitting diode (LED) chips and more particularly interconnect structures for improved LED chip performance are disclosed. Interconnect structures are disclosed within LED chips that are structured to increase perimeter contact areas within localized LED chip areas without substantial increases to overall areas occupied by the interconnect structures. By increasing contact perimeters of interconnects within a certain area, increased current injection efficiency may be provided. Interconnect structures for increased current injection are disclosed for both n-type layers and p-type layers. Interconnect structures may include patterned dielectric materials within interconnect openings and corresponding interconnects that are formed around the patterned dielectric materials. Additional interconnect structures include nested patterns and extensions that provide enhanced adhesion along LED chip perimeters.

Inventors

Michael Check
Justin White
Steven Wuester
Kevin Haberern
Colin Blakely
Jesse Reiherzer

Assignees

CREELED, INC.

Dates

Publication Date: 20260505
Application Date: 20230418

Claims (20)

1 . A light-emitting diode (LED) chip, comprising: an active LED structure comprising an n-type layer, a p-type layer, and an active layer arranged between the n-type layer and the p-type layer, the active LED structure forming a first opening that extends through the p-type layer, the active layer, and a portion of the n-type layer; a dielectric material on a portion of the n-type layer within the first opening; an n-contact interconnect that is electrically connected to the n-type layer within the first opening, the n-contact interconnect forming one or more edges that extend from the n-contact interconnect to electrically contact the n-type layer around a perimeter of the dielectric material; a reflective structure on the p-type layer, wherein the reflective structure comprises a dielectric layer and a metal layer; and a reflective layer interconnect that extends through a second opening of the dielectric layer; wherein a portion of the dielectric layer is arranged within the second opening and the reflective layer interconnect forms one or more edges that extend from the reflective layer interconnect to form an electrically conductive path to the p-type layer around a perimeter of the portion of the dielectric layer.
2 . The LED chip of claim 1 , wherein the dielectric material on the portion of the n-type layer within the first opening comprises a same material as the dielectric layer of the reflective structure.
3 . The LED chip of claim 1 , further comprising an adhesion layer between the dielectric layer and the p-type layer, wherein a portion of the adhesion layer and the dielectric layer covers sidewalls of the p-type layer, the active layer, and the n-type layer within the first opening.
4 . The LED chip of claim 3 , further comprising a passivation layer within the first opening in a position that is between the n-contact interconnect and the dielectric layer of the reflective structure.
5 . The LED chip of claim 4 , further comprising an n-contact metal layer that laterally extends across the active LED structure, wherein the n-contact metal layer is electrically coupled to the n-contact interconnect, and the passivation layer is further arranged between the n-contact metal layer and the metal layer of the reflective structure.
6 . The LED chip of claim 1 , wherein the n-contact interconnect electrically contacts the n-type layer around an entire perimeter of the dielectric material.
7 . The LED chip of claim 1 , wherein the dielectric material is provided at a center of the first opening, and the n-contact interconnect radially contacts the n-type layer around the perimeter of the dielectric material within the first opening.
8 . The LED chip of claim 1 , wherein the dielectric material forms a circular shape with a hollow center within the first opening, and the n-contact interconnect radially contacts the n-type layer around the perimeter of the dielectric material and within the hollow center of the dielectric material.
9 . The LED chip of claim 1 , wherein: a first portion of the dielectric material forms a circular shape with a hollow center within the first opening; a second portion of the dielectric material is provided within the hollow center; the n-contact interconnect contacts the n-type layer around a perimeter of the first portion of the dielectric material; and the n-contact interconnect contacts the n-type layer within the hollow center and between the first portion of the dielectric material and the second portion of the dielectric material.
10 . The LED chip of claim 1 , wherein the one or more edges of the n-contact interconnect form a plurality of separated portions of the n-contact interconnect.
11 . A light-emitting diode (LED) chip, comprising: an active LED structure comprising an n-type layer, a p-type layer, and an active layer arranged between the n-type layer and the p-type layer, the active LED structure forming a first opening that extends through the p-type layer, the active layer, and a portion of the n-type layer; an n-contact interconnect that is electrically connected to the n-type layer within the first opening; a reflective structure on the p-type layer, the reflective structure comprising a dielectric layer, a metal layer, and a first dielectric layer opening that is formed through the dielectric layer; and a first reflective layer interconnect that extends through the first dielectric layer opening, the first reflective layer interconnect forming a first ring that forms a first electrically conductive path to the p-type layer around a perimeter of the n-contact interconnect.
12 . The LED chip of claim 11 , further comprising a second dielectric layer opening through the dielectric layer of the reflective structure, and a second reflective layer interconnect that extends through the second dielectric layer opening, the second reflective layer interconnect forming a second ring that forms a second electrically conductive path to the p-type layer around a perimeter of the first ring.
13 . The LED chip of claim 11 , wherein a portion of the dielectric layer of the reflective structure is on a portion of the n-type layer within the first opening, and the n-contact interconnect electrically contacts the n-type layer around a perimeter of the dielectric layer within the first opening.
14 . The LED chip of claim 11 , wherein: the n-contact interconnect is one of a plurality of n-contact interconnects electrically coupled to the n-type layer across the active LED structure; and the first ring is one of a plurality of rings electrically coupled to the p-type layer such that a perimeter of each n-contact interconnect of the plurality of n-contact interconnects is surrounded by at least one ring of the plurality of rings.
15 . The LED chip of claim 14 , further comprising additional reflective layer interconnects that extend through the first dielectric layer opening to form an array pattern of vias that are electrically coupled with the p-type layer between adjacent rings of the plurality of rings.
16 . The LED chip of claim 15 , wherein diameters of the additional reflective layer interconnects decrease with increasing distance from each of the plurality of n-contact interconnects.
17 . A light-emitting diode (LED) chip, comprising: an active LED structure comprising an n-type layer, a p-type layer, and an active layer arranged between the n-type layer and the p-type layer; a reflective structure on the p-type layer, the reflective structure comprising a dielectric layer, a metal layer, and a first dielectric layer opening that is formed through the dielectric layer; and a first reflective layer interconnect that extends through the first dielectric layer opening, the first reflective layer interconnect forming an electrically conductive path to the p-type layer around a perimeter of the active LED structure.
18 . The LED chip of claim 17 , further comprising: a plurality of n-contact interconnects electrically connected to the n-type layer through a plurality of openings of the active LED structure, the plurality of openings extending through the p-type layer and the active layer; wherein the first reflective layer interconnect extends around a perimeter of the active LED structure to laterally surround the plurality of n-contact interconnects.
19 . The LED chip of claim of claim 17 , further comprising: a plurality of second reflective layer interconnects that extend through a plurality of second dielectric layer openings formed through the dielectric layer of the reflective structure; wherein the first reflective layer interconnect extends around a perimeter of the active LED structure to laterally surround the plurality of second reflective layer interconnects.
20 . The LED chip of claim 19 , further comprising: a plurality of n-contact interconnects electrically connected to the n-type layer through a plurality of openings of the active LED structure, the plurality of openings extending through the p-type layer and the active layer; wherein certain ones of the plurality of second reflective layer interconnects form rings around certain ones of the plurality of n-contact interconnects; and wherein other ones of the plurality of second reflective layer interconnects form an array pattern of vias.

Description

RELATED APPLICATIONS This application claims the benefit of provisional patent application Ser. No. 63/365,638, filed Jun. 1, 2022, the disclosure of which is hereby incorporated herein by reference in its entirety. FIELD OF THE DISCLOSURE The present disclosure relates to solid-state lighting devices including light-emitting diodes (LEDs) and more particularly to interconnect structures for improved LED chip performance. BACKGROUND Solid-state lighting devices such as light-emitting diodes (LEDs) are increasingly used in both consumer and commercial applications. Advancements in LED technology have resulted in highly efficient and mechanically robust light sources with a long service life. Accordingly, modern LEDs have enabled a variety of new display applications and are being increasingly utilized for general illumination applications, often replacing incandescent and fluorescent light sources. LEDs are solid-state devices that convert electrical energy to light and generally include one or more active layers of semiconductor material (or an active region) arranged between oppositely doped n-type and p-type layers. When a bias is applied across the doped layers, holes and electrons are injected into the one or more active layers where they recombine to generate emissions such as visible light or ultraviolet emissions. An active region may be fabricated, for example, from silicon carbide, gallium nitride, gallium phosphide, aluminum nitride, and/or gallium arsenide-based materials and/or from organic semiconductor materials. Photons generated by the active region are initiated in all directions. Typically, it is desirable to operate LEDs at the highest light emission efficiency, which can be measured by the emission intensity in relation to the output power (e.g., in lumens per watt). A practical goal to enhance emission efficiency is to maximize extraction of light emitted by the active region in the direction of the desired transmission of light. Light extraction and external quantum efficiency of an LED can be limited by a number of factors, including internal reflection. If photons are internally reflected in a repeated manner, then such photons will eventually be absorbed and never provide visible light that exits an LED. To increase the opportunity for photons to exit an LED, it has been found useful to pattern, roughen, or otherwise texture the interface between an LED surface and the surrounding environment to provide a varying surface that increases the probability of refraction over internal reflection and thus enhances light extraction. Reflective surfaces may also be provided to reflect generated light so that such light may contribute to useful emission from an LED chip. LEDs have been developed with internal reflective surfaces or layers to reflect generated light. The quantum efficiency of an LED can also be limited by other factors, such as how well current is able to spread within an LED. To increase current spreading for LEDs, and in particular for larger area LEDs, it has been found useful to add layers of high electrical conductivity over one or more epitaxial layers of an LED. Additionally, electrodes for the LEDs can have larger surface area and may include various electrode extensions or fingers that are configured to route and more evenly distribute current across an LED. As advancements in modern LED technology progress, the art continues to seek improved LEDs and solid-state lighting devices having desirable illumination characteristics capable of overcoming challenges associated with conventional lighting devices. SUMMARY The present disclosure relates to solid-state lighting devices including light-emitting diodes (LEDs) and more particularly to interconnect structures for improved LED chip performance. Interconnect structures are disclosed within LED chips that are structured to increase perimeter contact areas within localized LED chip areas without substantial increases to overall areas occupied by the interconnect structures. By increasing contact perimeters of interconnects within a certain area, increased current injection efficiency may be provided. Interconnect structures for increased current injection are disclosed for both n-type layers and p-type layers. Interconnect structures may include patterned dielectric materials within interconnect openings and corresponding interconnects that are formed around the patterned dielectric materials. Additional interconnect structures include nested patterns and extensions that provide enhanced adhesion along LED chip perimeters. In one aspect, an LED chip comprises: an active LED structure comprising an n-type layer, a p-type layer, and an active layer arranged between the n-type layer and the p-type layer, the active LED structure forming a first opening that extends through the p-type layer, the active layer, and a portion of the n-type layer; a dielectric material on a portion of the n-type layer within the first opening; an