North Carolina State University

Kyma Technologies, Inc.

Eric Porter Carlson

Thomas Gehrke

Kevin J Linthicum

Robert F Davis

Pradeep Rajagopal

Darren B Thomson

Jerome J Cuomo

Andrew David Hanser

N Mark Williams

Darin Taze Thomas

Andrew D Hanser

Darin T Thomas

An underlying gallium nitride layer on a silicon carbide substrate is masked with a mask that includes an array of openings therein, and the underlying gallium nitride layer is etched through the array of openings to define posts in the underlying gallium nitride layer and trenches therebetween. The posts each include a sidewall and a top having the mask thereon. The sidewalls of the posts are laterally grown into the trenches to thereby form a gallium nitride semiconductor layer. During this lateral growth, the mask prevents nucleation and vertical growth from the tops of the posts. Accordingly, growth proceeds laterally into the trenches, suspended from the sidewalls of the posts. The sidewalls of the posts may be laterally grown into the trenches until the laterally grown sidewalls coalesce in the trenches to thereby form a gallium nitride semiconductor layer. The lateral growth from the sidewalls of the posts may be continued so that the gallium nitride layer grows vertically through the openings in the mask and laterally overgrows onto the mask on the tops of the posts, to thereby form a gallium nitride semiconductor layer. The lateral overgrowth can be continued until the grown sidewalls coalesce on the mask to thereby form a continuous gallium nitride semiconductor layer. Microelectronic devices may be formed in the continuous gallium nitride semiconductor layer.

Pendeoepitaxial gallium nitride semiconductor layers on silicon carbide substrates

A high deposition rate sputter method is utilized to produce bulk, single-crystal, low-defect density Group III nitride materials suitable for microelectronic and optoelectronic devices and as substrates for subsequent epitaxy, and to produce highly oriented polycrystalline windows. A template material having an epitaxial-initiating growth surface is provided. A Group III metal target is sputtered in a plasma-enhanced environment using a sputtering apparatus comprising a non-thermionic electron/plasma injector assembly, thereby to producing a Group III metal source vapor. The Group III metal source vapor is combined with a nitrogen-containing gas to produce a reactant vapor species comprising Group III metal and nitrogen. The reactant vapor species is deposited on the growth surface to produce a single-crystal M N layer thereon. The template material is removed, thereby providing a free-standing, single-crystal M N article having a diameter of approximately 0.5 inch or greater and a thickness of approximately 50 microns or greater.

MIIIN based materials and methods and apparatus for producing same

A method utilizes sputter transport techniques to produce arrays or layers of self-forming, self-oriented columnar structures characterized as discrete, single-crystal Group III nitride posts or columns on various substrates. The columnar structure is formed in a single growth step, and therefore does not require processing steps for depositing, patterning, and etching growth masks. A Group III metal source vapor is produced by sputtering a target, for combination with nitrogen supplied from a nitrogen-containing source gas. The III/V ratio is adjusted or controlled to create a Group III metal-rich environment within the reaction chamber conducive to preferential column growth. The reactant vapor species are deposited on the growth surface to produce single-crystal M N columns thereon. The columns can be employed as a strain-relieving platform for the growth of continuous, low defect-density, bulk materials. Additionally, the growth conditions can be readjusted to effect columnar epitaxial overgrowth, wherein coalescence of the Group III nitride material occurs at the tops of the columns, thereby forming a substantially continuous layer upon which additional layers can be deposited. The intervening presence of the column structure mitigates thermal mismatch stress between substrates, films, or other layers above and below the columns. A high deposition rate sputter method utilizing a non-thermionic electron/plasma injector assembly is provided to carrying out one or more of the growth steps.

Method and apparatus for producing MIIIN columns and MIIIN materials grown thereon

PENDEOEPITAXIAL METHODS OF FABRICATING GALLIUM NITRIDE SEMICONDUCTOR LAYERS ON SILICON CARBIDE SUBSTRATES BY LATERAL GROWTH FROM SIDEWALLS OF MASKED POSTS, AND GALLIUM NITRIDE SEMICONDUCTOR STRUCTURES FABRICATED THEREBY

Pendeoepitaxial gallium nitride semiconductor layers on silcon carbide substrates

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Raleigh, NC, United States of America

Eric Porter Carlson