Palo Alto Research Center Inc.

Andre Strittmatter

Christopher L Chua

Noble Marshall Johnson

Zhihong Yang

Mark Teepe

Peter Kiesel

John E Northrup

Joerg Martini

A semiconductor light emitting device includes a pump light source, a gain structure, and an out-coupling mirror. The gain structure is comprised of InGaN layers that have resonant excitation absorption at the pump wavelength. Light from the pump light source causes the gain structure to emit light, which is reflected by the out-coupling mirror back to the gain structure. A distributed Bragg reflector causes internal reflection within the gain structure. The out-coupling mirror permits light having sufficient energy to pass therethrough for use external to the device. A frequency doubling structure may be disposed between the gain structure and the out-coupling mirror. Output wavelengths in the deep-UV spectrum may be achieved.

Vertical surface emitting semiconductor device

A structure method for producing same provides suppressed lattice defects when epitaxially forming nitride layers over non-c-plane oriented layers, such as a semi-polar oriented template layer or substrate. A patterned mask with 'window' openings, or trenches formed in the substrate with appropriate vertical dimensions, such as the product of the window width times the cotangent of the angle between the surface normal and the c-axis direction, provides significant blocking of all diagonally running defects during growth. In addition, inclined posts of appropriate height and spacing provide a blocking barrier to vertically running defects is created. When used in conjunction with the aforementioned aspects of mask windows or trenches, the post structure provides significant blocking of both vertically and diagonally running defects during growth.

Nitride semiconductor structure

A structure and method for producing same provides a solid-state light emitting device with suppressed lattice defects in epitaxially formed nitride layers over a non-c-plane oriented (e.g., semi-polar) template or substrate. A dielectric layer with 'window' openings or trenches provides significant suppression of all diagonally running defects during growth. Posts of appropriate height and spacing may further provide suppression of vertically running defects. A layer including gallium nitride is formed over the dielectric layer, and polished to provide a planar growth surface with desired roughness. A tri-layer indium gallium nitride active region is employed. For laser diode embodiments, a relatively thick aluminum gallium nitride cladding layer is provided over the gallium nitride layer.

Semi-polar nitride-based light emitting structure and method of forming same

A structure method for producing same provides suppressed lattice defects when epitaxially forming nitride layers over non-c-plane oriented layers, such as a semi-polar oriented template layer or substrate. A patterned mask with 'window' openings, or trenches formed in the substrate with appropriate vertical dimensions, such as the product of the window width times the cotangent of the angle between the surface normal and the c-axis direction, provides significant blocking of all diagonally running defects during growth. In addition, inclined posts of appropriate height and spacing provide a blocking barrier to vertically running defects is created. When used in conjunction with the aforementioned aspects of mask windows or trenches, the post structure provides sign0ificant blocking of both vertically and diagonally running defects during growth.

Nitride semiconductor structure and method of making same

A relaxed InGaN template is formed by growing a GaN or InGaN nucleation layer at low temperatures on a conventional base layer (e.g., sapphire). The nucleation layer is typically very rough and multi-crystalline. A single-crystal InGaN buffer layer is then grown at normal temperatures on the nucleation layer. Although not necessary, the buffer layer is typically undoped, and is usually grown at high pressures to encourage planarization and to improve surface smoothness. A subsequent n-doped cap layer can then be grown at low pressures to form the n-contact of a photonic or electronic device. In some cases, a wetting layer&#x2014;typically low temperature AlN&#x2014;is grown prior to the nucleation layer. Other templates, such as AlGaN on Si or SiC, are also produced using the method of the present invention.

Relaxed InGaN/AlGaN templates

A relaxed InGaN template employs a GaN or InGaN nucleation layer grown at low temperatures on a conventional base layer (e.g., sapphire). The nucleation layer is typically very rough and multi-crystalline. A single-crystal InGaN buffer layer is then grown at normal temperatures. Although not necessary, the buffer layer is typically undoped, and is usually grown at high pressures to encourage planarization and to improve surface smoothness. A subsequent n-doped cap layer can then be grown at low pressures to form the n-contact of a photonic or electronic device. In some cases, a wetting layer&#x2014;typically low temperature AlN&#x2014;is grown prior to the nucleation layer. Other templates, such as AlGaN on Si or SiC, are also produced using the method of the present invention.

A semiconductor light-emitting device has, in place of a traditional separate cladding layer and contact structure, a non-epitaxial contact and waveguide layer. The non-epitaxial contact and waveguide layer is formed of a conductive material and such that it has a recess therein and over the injection region. Air filling the region together with appropriate choice of material for the non-epitaxial contact and waveguide layer creates desired lateral waveguiding. Metallic silver in one choice for this material. The recess may also be filled with a low-loss material having a refractive index higher than that of the material forming the non-epitaxial contact and waveguide layer. Transparent conductive oxides (e.g., indium tin oxide (ITO), zinc oxide (ZnO), etc.), appropriate metal (e.g., gold), or a composite comprising a conductive oxide and a metal, provide low absorption in the UV and near-IR wavelengths of interest, and are thus good candidate materials for within the recess.

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Menlo Park, CA, United States of America

Andre Strittmatter