Ostendo Technologies, Inc.

Anna Volkova

Vladimir Ivantsov

Alexander L Syrkin

Lisa Shapovalov

Hussein S El-Ghoroury

Vladimir A Dmitriev

Vitali Soukhoveev

Oleg V Kovalenkov

Alexander Usikov

Vladimir Sizov

Benjamin A Haskell

Philippe Spiberg

A method for growing on a substrate strongly aligned uniform cross-section semiconductor composite nanocolumns is disclosed. The method includes: (a) forming faceted pyramidal pits on the substrate surface; (b) initiating nucleation on the facets of the pits; and; (c) promoting the growth of nuclei toward the center of the pits where they coalesce with twinning and grow afterwards together as composite nanocolumns. Multi-quantum-well, core-shell nanocolumn heterostructures can be grown on the sidewalls of the nanocolumns. Furthermore, a continuous semiconductor epitaxial layer can be formed through the overgrowth of the nanocolumns to facilitate fabrication of high-quality planar device structures or for light emitting structures.

Methods for producing composite GaN nanocolumns and light emitting structures made from the methods

Apparatus and methods for controlling gas flows in a HVPE reactor. Gas flows may be controlled by a gas focusing element. Gas injection and gas collection tubes are positioned within an outer tube and are separated from each other to define a space there between. A gas, such as HCl gas, flows over the outer surfaces of the injection and collection tubes to contain gases within the space as they flow from the injection tube to the collection tube and over a seed upon which group III nitride materials are grown. Gas flows may also be controlled by a multi-tube structure that separates gases until they reach a grown zone. A multi-tube structure may include four tubes, which separate flows of a halide reactive gas, a reaction product that flows with a carrier gas, and ammonia.

Apparatus and methods for controlling gas flows in a HVPE reactor

The present invention relates to a method for producing a modified surface of a substrate that stimulates the growth of epitaxial layers of group-III nitride semiconductors with substantially improved structural perfection and surface flatness. The modification is conducted outside or inside a growth reactor by exposing the substrate to a gas-product of the reaction between hydrogen chloride (HCl) and aluminum metal (Al). As a single-step or an essential part of the multi-step pretreatment procedure, the modification gains in coherent coordination between the substrate and group-III nitride epitaxial structure to be deposited. Along with epilayer, total epitaxial structure may include buffer inter-layer to accomplish precise substrate-epilayer coordination. While this modification is a powerful tool to make high-quality group-III nitride epitaxial layers attainable even on foreign substrates having polar, semipolar and nonpolar orientation, it remains gentle enough to keep the surface of the epilayer extremely smooth. Various embodiments are disclosed.

Method for substrate pretreatment to achieve high-quality III-nitride epitaxy

HVPE reactors and methods for growth of p-type group III nitride materials including p-GaN. A reaction product such as gallium chloride is delivered to a growth zone inside of a HVPE reactor by a carrier gas such as Argon. The gallium chloride reacts with a reactive gas such as ammonia in the growth zone in the presence of a magnesium-containing gas to grow p-type group III nitride materials. The source of magnesium is an external, non-metallic compound source such as Cp2Mg.

HVPE apparatus and methods for growth of p-type single crystal group III nitride materials

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Gaithersburg, MD, United States of America

Anna Volkova