Cree Gmbh

Wolfspeed, Inc.

Cree Research Inc.

Valeri Fedorovich Tsvetkov

Cem Basceri

Adrian Powell

Robert Tyler Leonard

Calvin H Carter, Jr

Mark Brady

Hudson McDonald Hobgood

Jason Ronald Jenny

Stephan Georg Mueller

David Phillip Malta

Elif Balkas

Yuri Khlebnikov

Simon Bubel

Michael J Paisley

Steven Griffiths

Gerald H Negley

Yifeng Wu

David Beardsley Slater, Jr

Alexander V Suvorov

Robert C Glass

Matthew David Conrad

Caleb A Kent

Varad R Sakhalkar

Oleksandr Kramarenko

Eugene Deyneka

George J Fechko, Jr

Mrinal Kanti Das

Jeffrey C Seaman

Curt Progl

Joseph John Sumakeris

Michael James Paisley

Cengiz Balkas

Murat N Silan

Vijay Balakrishna

Alexander Kevin Shveyd

Igor Khlebnikov

Michael Fusco

Lukas Nattermann

Kathy Doverspike

Calvin H Carter

David P Malta

Stephen G Mueller

Kathryn A O'Hara

Hudson McDONALD Hobgood

David Philip Malta

Hudson Mcd Hobgood

Jr David B Slater

Jr Calvin H Carter

George John Fechko

Carter H Carter

Silicon carbide (SiC) wafers and related methods are disclosed that include large diameter SiC wafers with wafer shape characteristics suitable for semiconductor manufacturing. Large diameter SiC wafers are disclosed that have reduced deformation related to stress and strain effects associated with forming such SiC wafers. As described herein, wafer shape and flatness characteristics may be improved by reducing crystallographic stress profiles during growth of SiC crystal boules or ingots. Wafer shape and flatness characteristics may also be improved after individual SiC wafers have been separated from corresponding SiC crystal boules. In this regard, SiC wafers and related methods are disclosed that include large diameter SiC wafers with suitable crystal quality and wafer shape characteristics including low values for wafer bow, warp, and thickness variation.

Large diameter silicon carbide wafers

Silicon carbide (SiC) materials including SiC wafers and SiC boules and related methods are disclosed that provide large dimension SiC wafers with reduced crystallographic stress. Growth conditions for SiC materials include maintaining a generally convex growth surface of SiC crystals, adjusting differences in front-side to back-side thermal profiles of growing SiC crystals, supplying sufficient source flux to allow commercially viable growth rates for SiC crystals, and reducing the inclusion of contaminants or non-SiC particles in SiC source materials and corresponding SiC crystals. By forming larger dimension SiC crystals that exhibit lower crystallographic stress, overall dislocation densities that are associated with missing or additional planes of atoms may be reduced, thereby improving crystal quality and usable SiC crystal growth heights.

Large dimension silicon carbide single crystalline materials with reduced crystallographic stress

Silicon carbide (SiC) crystalline materials and related methods are disclosed that provide SiC crystalline materials with reduced optical absorption. In certain aspects, SiC crystalline materials with reduced absorption coefficients for wavelengths of light within the visible spectrum are disclosed. Various peaks in absorption over a wavelength spectrum may be reduced in SiC crystalline materials to improve overall absorption coefficient uniformity across the visible spectrum. By providing such improvements in absorption coefficients for SiC crystalline materials, reduced reflection and transmission losses of light in corresponding devices may be realized. Related methods are disclosed that include various combinations of crystalline growth, with and without various post-growth thermal conditioning steps.

Reduced optical absorption for silicon carbide crystalline materials

Silicon carbide (SiC) wafers, SiC boules, and related methods are disclosed that provide improved dislocation distributions. SiC boules are provided that demonstrate reduced dislocation densities and improved dislocation uniformity across longer boule lengths. Corresponding SiC wafers include reduced total dislocation density (TDD) values and improved TDD radial uniformity. Growth conditions for SiC crystalline materials include providing source materials in oversaturated quantities where amounts of the source materials present during growth are significantly higher than what would typically be required. Such SiC crystalline materials and related methods are suitable for providing large diameter SiC boules and corresponding SiC wafers with improved crystalline quality.

Dislocation distribution for silicon carbide crystalline materials

A method is disclosed for producing a high quality bulk single crystal of silicon carbide in a seeded growth system by reducing the separation between a silicon carbide seed crystal and a seed holder until the conductive heat transfer between the seed crystal and the seed holder dominates the radiative heat transfer between the seed crystal and the seed holder over substantially the entire seed crystal surface that is adjacent the seed holder.

Method of producing high quality silicon carbide crystal in a seeded growth system

Producing high quality bulk silicon carbide single crystal by managing thermal stresses at a seed interface

A method is disclosed for producing high quality semi-insulating silicon carbide crystals in the absence of relevant amounts of deep level trapping elements. The invention includes the steps of heating a silicon carbide crystal having a first concentration of point defects to a temperature that thermodynamically increases the number of point defects and resulting states in the crystal, and then cooling the heated crystal at a sufficiently rapid rate to maintain an increased concentration of point defects in the cooled crystal.

Method for producing semi-insulating resistivity in high purity silicon carbide crystals

A high quality single crystal wafer of SiC is disclosed having a diameter of at least about 3 inches and a 1 c screw dislocation density from about 500 cmto about 2000 cm.

Low 1C screw dislocation 3 inch silicon carbide wafer

A process is described for producing silicon carbide crystals having increased minority carrier lifetimes. The process includes the steps of heating and slowly cooling a silicon carbide crystal having a first concentration of minority carrier recombination centers such that the resultant concentration of minority carrier recombination centers is lower than the first concentration.

Process for producing silicon carbide crystals having increased minority carrier lifetimes

A high quality single crystal wafer of SiC is disclosed having a diameter of at least about 3 inches and a 1c screw dislocation density of less than about 2000 cm.

A physical vapor transport growth technique for silicon carbide is disclosed. The method includes the steps of introducing a silicon carbide powder and a silicon carbide seed crystal into a physical vapor transport growth system, separately introducing a heated silicon-halogen gas composition into the system in an amount that is less than the stoichiometric amount of the silicon carbide source powder so that the silicon carbide source powder remains the stoichiometric dominant source for crystal growth, and heating the source powder, the gas composition, and the seed crystal in a manner that encourages physical vapor transport of both the powder species and the introduced silicon-halogen species to the seed crystal to promote bulk growth on the seed crystal.

Halogen assisted physical vapor transport method for silicon carbide growth

One hundred millimeter single crystal silicon carbide wafer

A semiconductor light emitting diode includes a semiconductor substrate, an epitaxial layer of n-type Group III nitride on the substrate, a p-type epitaxial layer of Group III nitride on the n-type epitaxial layer and forming a p-n junction with the n-type layer, and a resistive gallium nitride region on the n-type epitaxial layer and adjacent the p-type epitaxial layer for electrically isolating portions of the p-n junction. A metal contact layer is formed on the p-type epitaxial layer. In method embodiments disclosed, the resistive gallium nitride border is formed by forming an implant mask on the p-type epitaxial region and implanting ions into portions of the p-type epitaxial region to render portions of the p-type epitaxial region semi-insulating. A photoresist mask or a sufficiently thick metal layer may be used as the implant mask.

LED fabrication via ion implant isolation

Growing community of inventors

Durham, NC, United States of America

Valeri Fedorovich Tsvetkov