Cree Gmbh

The United States of America As Represented by the Department of Energy

Creeled, Inc.

Ting Li

James Ibbetson

Monica Hansen

Max Batres

Bernd P Keller

David T Emerson

Michael John Bergmann

Adam William Saxler

Kevin Haberern

Jayesh Bharathan

Mark Raffetto

John Adam Edmond

Matthew Donofrio

Sten Heikman

Matthew Jacob-Mitos

James Ibbeston

A composite high reflectivity mirror (CHRM) with at least one relatively smooth interior surface interface. The CHRM includes a composite portion, for example dielectric and metal layers, on a base element. At least one of the internal surfaces is polished to achieve a smooth interface. The polish can be performed on the surface of the base element, on various layers of the composite portion, or both. The resulting smooth interface(s) reflect more of the incident light in an intended direction. The CHRMs may be integrated into light emitting diode (LED) devices to increase optical output efficiency.

High reflectivity mirrors and method for making same

A flip-chip semiconductor based Light Emitting Device (LED) can include an n-type semiconductor substrate and an n-type GaN epi-layer on the substrate. A p-type GaN epi-layer can be on the n-type GaN epi-layer and a metal ohmic contact p-electrode can be on the p-type GaN epi-layer, where the metal ohmic contact p-electrode can have an average thickness less than about 25 &#x212b;. A reflector can be on the metal ohmic contact p-electrode and a metal stack can be on the reflector. An n-electrode can be on the substrate opposite the n-type GaN epi-layer and a bonding pad can be on the n-electrode.

Ultra-thin ohmic contacts for p-type nitride light emitting devices

A high efficiency light emitting diode with a composite high reflectivity layer integral to said LED to improve emission efficiency. One embodiment of a light emitting diode (LED) chip comprises an LED and a composite high reflectivity layer integral to the LED to reflect light emitted from the active region. The composite layer comprises a first layer, and alternating plurality of second and third layers on the first layer, and a reflective layer on the topmost of said plurality of second and third layers. The second and third layers have a different index of refraction, and the first layer is at least three times thicker than the thickest of the second and third layers. For composite layers internal to the LED chip, conductive vias can be included through the composite layer to allow an electrical signal to pass through the composite layer to the LED.

Composite high reflectivity layer

A high efficiency light emitting diode with a composite high reflectivity layer integral to said LED or package to improve emission efficiency. One embodiment of a light emitting diode (LED) chip comprises a LED and a composite high reflectivity layer integral to the LED to reflect light emitted from the active region. One embodiment of a LED package comprises a LED mounted on a substrate with an encapsulant over said LED and a composite high reflectivity layer arranged to reflect emitted light. The composite layer comprises a plurality of layers such that at least one of said plurality of layers has an index of refraction lower than the encapsulant and a reflective layer on a side of said plurality of layers opposite the LED. In some embodiments, conductive vias are included through the composite layer to allow an electrical signal to pass through the layer to the LED.

The surface morphology of an LED light emitting surface is changed by applying a reactive ion etch (RIE) process to the light emitting surface. Etched features, such as truncated pyramids, may be formed on the emitting surface, prior to the RIE process, by cutting into the surface using a saw blade or a masked etching technique. Sidewall cuts may also be made in the emitting surface prior to the RIE process. A light absorbing damaged layer of material associated with saw cutting is removed by the RIE process. The surface morphology created by the RIE process may be emulated using different, various combinations of non-RIE processes such as grit sanding and deposition of a roughened layer of material or particles followed by dry etching.

LED with substrate modifications for enhanced light extraction and method of making same

The surface morphology of an LED light emitting surface is changed by applying a reactive ion etch (RIE) process to the light emitting surface. High aspect ratio, submicron roughness is formed on the light emitting surface by transferring a thin film metal hard-mask having submicron patterns to the surface prior to applying a reactive ion etch process. The submicron patterns in the metal hard-mask can be formed using a low cost, commercially available nano-patterned template which is transferred to the surface with the mask. After subsequently binding the mask to the surface, the template is removed and the RIE process is applied for time duration sufficient to change the morphology of the surface. The modified surface contains non-symmetric, submicron structures having high aspect ratio which increase the efficiency of the device.

Light emitting diode with high aspect ratio submicron roughness for light extraction and methods of forming

An improved bond pad design for increased light extraction efficiency for use in light emitting diodes (LEDs) and LED packages. Embodiments of the present invention incorporate a structure that physically isolates the bond pads from the primary emission surface, forcing the current to flow away from the bond pads first before traveling down into the semiconductor material toward the active region. This structure reduces the amount of light that is generated in the area near the bond pads, so that less of the generated light is trapped underneath the bond pads and absorbed.

Bond pad design for enhancing light extraction from LED chips

A semiconductor based Light Emitting Device (LED) can include a p-type nitride layer and a metal ohmic contact, on the p-type nitride layer. The metal ohmic contact can have an average thickness of less than about 25 &#x212b; and a specific contact resistivity less than about 10ohm-cm.

The surface morphology of an LED light emitting surface is changed by applying processes, such as a reactive ion etch (RIE) process to the light emitting surface. In one embodiment, the changed surface morphology takes the form of a moth-eye surface. The surface morphology created by the RIE process may be emulated using different combinations of non-RIE processes such as grit sanding and deposition of a roughened layer of material or particles followed by dry etching.

A light emitting diode is disclosed that includes an active structure, a first ohmic contact on the active structure, and a transparent conductive oxide layer on the active structure opposite the first ohmic contact. The transparent conductive oxide layer has a larger footprint than said active structure. A dielectric mirror is positioned on the transparent conductive oxide layer opposite said active structure and a second contact is positioned on the transparent conductive oxide layer opposite the dielectric mirror and separated from the active structure.

Light emitting diode with a dielectric mirror having a lateral configuration

A method and apparatus for forming a porous layer on the surface of a semiconductor material wherein an electrolyte is provided and is placed in contact with one or more surfaces of a layer of semiconductor material. The electrolyte is heated and a bias is introduced across said electrolyte and the semiconductor material causing a current to flow between the electrolyte and the semiconductor material. The current forms a porous layer on the one or more surfaces of the semiconductor material in contact with the electrolyte. The semiconductor material with its porous layer can serve as a substrate for a light emitter. A semiconductor emission region can be formed on the substrate. The emission region is capable of emitting light omnidirectionally in response to a bias, with the porous layer enhancing extraction of the emitting region light passing through the substrate.

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Ventura, CA, United States of America

Ting Li