Kyma Technologies, Inc.

North Carolina State University

N Mark Williams

Andrew David Hanser

Xueping Xu

Edward Preble

Lianghong Liu

Denis Tsvetkov

Jerome J Cuomo

Eric Porter Carlson

Darin Taze Thomas

Andrew D Hanser

Darin T Thomas

Group III (Al, Ga, In)N single crystals, articles and films useful for producing optoelectronic devices (such as light emitting diodes (LEDs), laser diodes (LDs) and photodetectors) and electronic devices (such as high electron mobility transistors (HEMTs)) composed of III-V nitride compounds, and methods for fabricating such crystals, articles and films.

Group III nitride articles and methods for making same

Group III nitride articles having nucleation layers, transitional layers, and bulk layers

In a method for making a GaN article, an epitaxial nitride layer is deposited on a single-crystal substrate. A 3D nucleation GaN layer is grown on the epitaxial nitride layer by HVPE under a substantially 3D growth mode. A GaN transitional layer is grown on the 3D nucleation layer by HVPE under a condition that changes the growth mode from the substantially 3D growth mode to a substantially 2D growth mode. A bulk GaN layer is grown on the transitional layer by HVPE under the substantially 2D growth mode. A polycrystalline GaN layer is grown on the bulk GaN layer to form a GaN/substrate bi-layer. The GaN/substrate bi-layer may be cooled from the growth temperature to an ambient temperature, wherein GaN material cracks laterally and separates from the substrate, forming a free-standing article.

Single crystal group III nitride articles and method of producing same by HVPE method incorporating a polycrystalline layer for yield enhancement

In a method for making an inclusion-free uniformly semi-insulating GaN crystal, an epitaxial nitride layer is deposited on a substrate. A 3D nucleation GaN layer is grown on the epitaxial nitride layer by HVPE under a substantially 3D growth mode, wherein a surface of the nucleation layer is substantially covered with pits and the aspect ratio of the pits is essentially the same. A GaN transitional layer is grown on the nucleation layer by HVPE under a condition that changes the growth mode from the substantially 3D growth mode to a substantially 2D growth mode. After growing the transitional layer, a surface of the transitional layer is substantially pit-free. A bulk GaN layer is grown on the transitional layer by HVPE. After growing the bulk layer, a surface of the bulk layer is smooth and substantially pit-free. The GaN is doped with a transition metal during at least one of the foregoing GaN growth steps.

Inclusion-free uniform semi-insulating group III nitride substrates and methods for making same

Inclusion-free uniform semi-insulating group III nitride substrate and methods for making same

A sputter transport device comprises a sealed chamber, a negatively-biased target cathode holder disposed in the chamber, and a substrate holder disposed in the chamber and spaced at a distance from the target cathode. A target cathode is bonded to the target cathode holder. A magnetron assembly is disposed in the chamber proximate to the target cathode. A negatively-biased, non-thermionic electron/plasma injector assembly is disposed between the target cathode and the substrate holder. The injector assembly fluidly communicates with a gas source and includes a plurality of hollow cathodes. Each hollow cathode includes an orifice communicating with the chamber. The device can be used to produce thin-films and ultra-thick materials in polycrystalline, single-crystal and epitaxial forms, and thus to produce articles and devices that are useful as metallic or insulating coatings, and as bulk semiconductor and optoelectronic materials.

Non-thermionic sputter material transport device, methods of use, and materials produced thereby

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.

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Raleigh, NC, United States of America

N Mark Williams