Cree Gmbh

Wolfspeed, Inc.

Robert Tyler Leonard

Adrian Powell

Valeri Fedorovich Tsvetkov

Mark Brady

Jason Ronald Jenny

Yuri Khlebnikov

Hudson McDonald Hobgood

Stephan Georg Mueller

Matthew David Conrad

Elif Balkas

Edward Robert Van Brunt

Calvin H Carter, Jr

David Phillip Malta

Simon Bubel

Michael J Paisley

Steven Griffiths

Caleb A Kent

Oleksandr Kramarenko

Eugene Deyneka

Varad R Sakhalkar

Cem Basceri

Cengiz Balkas

George J Fechko, Jr

Vijay Balakrishna

Valeri T Tsvetkov

Jeffrey C Seaman

William A Thore

Igor Khlebnikov

Murat N Silan

Hudson McD Hobgood

Curt Progl

Alexander V Suvorov

Michael P Laughner

Davis Andrew McClure

Alexander Kevin Shveyd

Kathryn A O'Hara

Michael Fusco

Lukas Nattermann

Kathy Doverspike

David P Malta

Valerl F Tsvetkov

William H Brixius

Stephen G Mueller

Hudson McDONALD Hobgood

Davis Mcclure

Michael Paul Laughner

Hudson Mcd Hobgood

Valeri F Tsevtkov

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

A method of analyzing semiconductor wafers includes capturing a first image of a first crystalline material, etching a first surface of the first crystalline material to delineate etch defects in the first crystalline material, and capturing a second image of first crystalline material after etching the first surface of the first crystalline material. Based on the second image, labels of etch defects delineated in the first surface of the first crystalline material are generated. The first image and the labels of etch defects are spatially coordinated to form a defect map identifying one or more defects in the first image based on the delineated etch defects, and based on the defect map and nondestructive data obtained from a second crystalline material, defects in the second crystalline material are identified.

Nondestructive characterization for crystalline 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

Nondestructive characterization of crystalline wafers is provided, including defect detection, identification, and counting. Certain aspects relate to development of nondestructive, high fidelity defect characterization and/or dislocation counting methods based on deep neural networks. Certain aspects relate to nondestructive methods for defect characterization of silicon carbide (SiC) wafers. By subjecting SiC wafers to nondestructive defect characterization, SiC wafers in their final state may be characterized and subsequently used for device fabrication, vastly reducing the expense of the characterization process. Nondestructive defect characterization also allows for increased sampling and improved feedback loops between crystalline growth process development and subsequent device production.

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

Wafer images and related alignment methods for crystalline wafers are disclosed. Certain aspects relate to accessing and aligning images of a same or similar crystalline wafer captured from different imaging sources. Alignment may include determining spatial differences between shared crystalline features in various wafer images of the same or similar crystalline wafer and transforming at least one of the images according to the determined spatial differences. With sufficient alignment, information may be associated and/or transferred between the various images, thereby providing the capability of forming a combined wafer image and sub-images thereof with high resolution and spatial coordination between different image sources. Certain aspects relate to development of nondestructive, high fidelity defect characterization and/or dislocation counting methods in crystalline materials based on modern deep convolutional neural networks (DCNN).

Alignment for wafer images

The wafer fabrication technique uses an ion implantation process on the back side of the wafer to control the shape of the wafer. At least one first dopant is implanted into a front side of a wafer to dope the wafer. At least one second dopant is implanted into a back side of the wafer in a dopant profile to create a back side structure, where the back side structure controls a shape of the wafer. A blank wafer is provided that has an undoped front side and a form shaping back side structure on the back side. A doped wafer is provided that has a dopant implanted on the front side and a form shaping back side structure on the back side that least partially offsets the strain in the wafer induced by the front side dopant.

Methods and apparatuses related to shaping wafers fabricated by ion implantation

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

Micropipe-free, single crystal, silicon carbide (SiC) and related methods of manufacture are disclosed. The SiC is grown by placing a source material and seed material on a seed holder in a reaction crucible of the sublimation system, wherein constituent components of the sublimation system including the source material, reaction crucible, and seed holder are substantially free from unintentional impurities. By controlling growth temperature, growth pressure, SiC sublimation flux and composition, and a temperature gradient between the source material and the seed material or the SiC crystal growing on the seed material during the PVT process, micropipe-inducing process instabilities are eliminated and micropipe-free SiC crystal is grown on the seed material.

Micropipe-free silicon carbide and related method of manufacture

A method for controlled growth of silicon carbide and structures produced by the method are disclosed. A crystal of silicon carbide (SiC) can be grown by placing a sacrificial substrate in a growth zone with a source material. The source material may include a low-solubility impurity. SiC is then grown on the sacrificial substrate to condition the source material. The sacrificial substrate is then replaced with the final substrate, and SiC is grown on the final substrate. A single crystal of silicon carbide is produced, wherein the crystal of silicon carbide has substantially few micropipe defects. Such a crystal may also include a substantially uniform concentration of the low-solubility impurity, and may be used to make wafers and/or SiC die.

Method for controlled growth of silicon carbide and structures produced by same

A semiconductor crystal and associated growth method are disclosed. The crystal includes a seed portion and a growth portion on the seed portion. The seed portion and the growth portion form a substantially right cylindrical single crystal of silicon carbide. A seed face defines an interface between the growth portion and the seed portion, with the seed face being substantially parallel to the bases of the right cylindrical crystal and being off-axis with respect to a basal plane of the single crystal. The growth portion replicates the polytype of the seed portion and the growth portion has a diameter of at least about 100 mm.

One hundred millimeter SiC crystal grown on off-axis seed

A high quality single crystal wafer of SiC is disclosed having a diameter of at least about 100 mm and a micropipe density of less than about 25 cm.

Low micropipe 100 mm silicon carbide wafer

Growing community of inventors

Raleigh, NC, United States of America

Robert Tyler Leonard