University of California

King Abdulaziz City for Science and Technology

Erin C Young

Shuji Nakamura

Steven P DenBaars

James Stephen Speck

Benjamin P Yonkee

Arpan Chakraborty

Anurag Tyagi

Hiroaki Ohta

Tal Margalith

Feng Wu

John T Leonard

Asad J Mughal

Robert M Farrell

David Hwang

SeungGeun Lee

Jared Kearns

Stacy J Kowsz

Christopher D Pynn

Charles Forman

A Vertical Cavity Surface Emitting Laser (VCSEL) including a light emitting III-nitride active region including quantum wells (QWs), wherein each of the quantum wells have a thickness of more than 8 nm, a cavity length of at least 7 &#x3bb;, or at least 20 &#x3bb;, where lambda is a peak wavelength of the light emitted from the active region, layers with reduced surface roughness, a tunnel junction intracavity contact. The VCSEL is flip chip bonded using In&#x2014;Au bonding. This is the first report of a VCSEL capable of continuous wave operation.

III-nitride surface-emitting laser and method of fabrication

A III-nitride optoelectronic device includes at least one n-type layer, an active region grown on or above the n-type layer, at least one p-type layer grown on or above the active region, and a tunnel junction grown on or above the p-type layer. A conductive oxide may be wafer bonded on or above the tunnel junction, wherein the conductive oxide comprises a transparent conductor and may contain light extraction features on its non-bonded face. The tunnel junction also enables monolithic incorporation of electrically-injected and optically-pumped III-nitride layers, wherein the optically-pumped III-nitride layers comprise high-indium-content III-nitride layers formed as quantum wells (QWs) that are grown on or above the tunnel junction. The optically-pumped high-indium-content III-nitride layers emit light at a longer wavelength than the electrically-injected III-nitride layers.

III-nitride light emitting diodes with tunnel junctions wafer bonded to a conductive oxide and having optically pumped layers

A flip chip III-Nitride LED which utilizes a dielectric coating backed by a metallic reflector (e.g., aluminum or silver). High reflectivity and low resistance contacts for optoelectronic devices. Low ESD rating optoelectronic devices. A VCSEL comprising a tunnel junction for current and optical confinement.

Contact architectures for tunnel junction devices

A hybrid growth method for III-nitride tunnel junction devices uses metal-organic chemical vapor deposition (MOCVD) to grow one or more light-emitting or light-absorbing structures and ammonia-assisted or plasma-assisted molecular beam epitaxy (MBE) to grow one or more tunnel junctions. Unlike p-type gallium nitride (p-GaN) grown by MOCVD, p-GaN grown by MBE is conductive as grown, which allows for its use in a tunnel junction. Moreover, the doping limits of MBE materials are higher than MOCVD materials. The tunnel junctions can be used to incorporate multiple active regions into a single device. In addition, n-type GaN (n-GaN) can be used as a current spreading layer on both sides of the device, eliminating the need for a transparent conductive oxide (TCO) layer or a silver (Au) mirror.

Hybrid growth method for III-nitride tunnel junction devices

A III-Nitride LED which utilizes n-type III-Nitride layers for current spreading on both sides of the device. A multilayer dielectric coating is used underneath the wire bond pads, both LED contacts are deposited in one step, and the p-side wire bond pad is moved off of the mesa. The LED has a wall plug efficiency or External Quantum Efficiency (EQE) over 70%, a fractional EQE droop of less than 7% at 20 A/cmdrive current and less than 15% at 35 A/cmdrive current. The LEDs can be patterned into an LED array and each LED can have an edge dimension of between 5 and 50 &#x3bc;m. The LED emission wavelength can be below 400 nm and aluminum can be added to the n-type III-Nitride layers such that the bandgap of the n-type III-nitride layers is larger than the LED emission photon energy.

III-nitride tunnel junction light emitting diode with wall plug efficiency of over seventy percent

A physical vapor deposition (e.g., sputter deposition) method for III-nitride tunnel junction devices uses metal-organic chemical vapor deposition (MOCVD) to grow one or more light-emitting or light-absorbing structures and electron cyclotron resonance (ECR) sputtering to grow one or more tunnel junctions. In another method, the surface of the p-type layer is treated before deposition of the tunnel junction on the p-type layer. In yet another method, the whole device (including tunnel junction) is grown using MOCVD and the p-type layers of the III-nitride material are reactivated by lateral diffusion of hydrogen through mesa sidewalls in the III-nitride material, with one or more lateral dimensions of the mesa that are less than or equal to about 200 &#x3bc;m. A flip chip display device is also disclosed.

Methods for fabricating III-nitride tunnel junction devices

A III-nitride tunnel junction with a modified p-n interface, wherein the modified p-n interface includes a delta-doped layer to reduce tunneling resistance. The delta-doped layer may be doped using donor atoms comprised of Oxygen (O), Germanium (Ge) or Silicon (Si); acceptor atoms comprised of Magnesium (Mg) or Zinc (Zn); or impurities comprised of Iron (Fe) or Carbon (C).

III-nitride tunnel junction with modified P-N interface

A dislocation-free high quality template with relaxed lattice constant, fabricated by spatially restricting misfit dislocation(s) around heterointerfaces. This can be used as a template layer for high In composition devices. Specifically, the present invention prepares high quality InGaN templates (In composition is around 5-10%), and can grow much higher In-composition InGaN quantum wells (QWs) (or multi quantum wells (MQWs)) on these templates than would otherwise be possible.

Semipolar or nonpolar nitride-based devices on partially or fully relaxed alloys with misfit dislocations at the heterointerface

An epitaxial structure for a III-Nitride based optical device, comprising an active layer with anisotropic strain on an underlying layer, where a lattice constant and strain in the underlying layer are partially or fully relaxed in at least one direction due to a presence of misfit dislocations, so that the anisotropic strain in the active layer is modulated by the underlying layer.

Anisotropic strain control in semipolar nitride quantum wells by partially or fully relaxed aluminum indium gallium nitride layers with misfit dislocations

Growing community of inventors

Santa Barbara, CA, United States of America

Erin C Young