Ii-vi Incorporated

Ii-vi Delaware, Inc.

Ii-vi Advanced Materials, LLC

Varatharajan Rengarajan

Ilya Zwieback

Gary E Ruland

Avinash K Gupta

Xueping Xu

Thomas E Anderson

Ping Wu

Andrew E Souzis

Bryan K Brouhard

Michael C Nolan

Mark Ramm

Avinash Gupta

An optical device includes a vanadium compensated, high resistivity, SiC single crystal of 6H or 4H polytype, for transmitting light having a wavelength in a range of from 420 nm to 4.5 μm. The device may include a window, lens, prism, or waveguide. A system includes a source for generating light having a wavelength in a range of from 420 nm to 4.5 μm, and a device for receiving and transmitting the light, where the device includes a vanadium compensated, high resistivity, SiC single crystal of 6H or 4H polytype. The disclosure also relates to crystals and methods for optical applications, including an aluminum doped SiC crystal having residual nitrogen and boron impurities, where the aluminum concentration is greater than the combined concentrations of nitrogen and boron, and where an optical absorption coefficient is less than about 0.4 cmat a wavelength between about 400 nm to about 800 nm.

Vanadium-compensated 4H and 6H single crystals of optical grade, and silicon carbide crystals and methods for producing same

The present disclosure generally relates to silicon carbide crystals which may be used in optical applications, and to methods for producing the same. In one form, a composition includes an aluminum doped silicon carbide crystal having residual nitrogen and boron impurities. The concentration of aluminum in the silicon carbide crystal is greater than the combined concentrations of nitrogen and boron in the silicon carbide crystal, and the silicon carbide crystal includes an optical absorption coefficient of less than about 0.4 cmat a wavelength in a range between about 400 nm to about 800 nm.

Method for preparing an aluminum doped silicon carbide crystal by providing a compound including aluminum and oxygen in a capsule comprised of a first and second material

In an apparatus and method growing a SiC single crystal, a PVT growth apparatus is provided with a single crystal SiC seed and a SiC source material positioned in spaced relation in a growth crucible. A resistance heater heats the growth crucible such that the SiC source material sublimates and is transported via a temperature gradient that forms in the growth crucible in response to the heater heating the growth crucible to the single crystal SiC seed where the sublimated SiC source material condenses forming a growing SiC single crystal. Purely axial heat fluxes passing through the bottom and the top of the growth crucible form a flat isotherm at least at a growth interface of the growing SiC single crystal on the single crystal SiC seed.

Large diameter silicon carbide single crystals and apparatus and method of manufacture thereof

In a crystal growth apparatus and method, polycrystalline source material and a seed crystal are introduced into a growth ambient comprised of a growth crucible disposed inside of a furnace chamber. In the presence of a first sublimation growth pressure, a single crystal is sublimation grown on the seed crystal via precipitation of sublimated source material on the seed crystal in the presence of a flow of a first gas that includes a reactive component that reacts with and removes donor and/or acceptor background impurities from the growth ambient during said sublimation growth. Then, in the presence of a second sublimation growth pressure, the single crystal is sublimation grown on the seed crystal via precipitation of sublimated source material on the seed crystal in the presence of a flow of a second gas that includes dopant vapors, but which does not include the reactive component.

Vanadium compensated, SI SiC single crystals of NU and PI type and the crystal growth process thereof

A physical vapor transport (PVT) apparatus suitable for growing SiC boules comprises a crystal growth chamber (with a defined central vertical axis), a sealed crucible containing sublimation source material and including a seed fixture disposed in an offset position with respect to the central vertical axis of the apparatus, and a heat source disposed to surround the crystal growth chamber. The heat source is configured to raise the temperature within the sealed crucible such that the source material vaporizes and deposits on the seed wafer. The offset position of the seed fixture creates a radial temperature gradient across an exposed surface of the seed as the crystal boule is grown.

High quality silicon carbide crystals and method of making the same

In a method for growing bulk SiC single crystals using chemical vapor transport, wherein silicon acts as a chemical transport agent for carbon, a growth crucible is charged with a solid carbon source material and a SiC single crystal seed disposed therein in spaced relationship. A halosilane gas, such as SiCland a reducing gas, such as H, are introduced into the crucible via separate inlets and mix in the crucible interior. The crucible is heated in a manner that encourages chemical reaction between the halosilane gas and the reducing gas leading to the chemical reduction of the halosilane gas to elemental silicon (Si) vapor. The produced Si vapor is transported to the solid carbon source material where it reacts with the solid carbon source material yielding volatile Si-bearing and C-bearing molecules. The produced Si-bearing and C-bearing vapors are transported to the SiC single crystal seed and precipitate on the SiC single crystal seed causing growth of a SiC single crystal on the SiC single crystal seed.

Method for silicon carbide crystal growth by reacting elemental silicon vapor with a porous carbon solid source material

A method and system of forming large-diameter SiC single crystals suitable for fabricating high crystal quality SiC substrates of 100, 125, 150 and 200 mm in diameter are described. The SiC single crystals are grown by a seeded sublimation technique in the presence of a shallow radial temperature gradient. During SiC sublimation growth, a flux of SiC bearing vapors filtered from carbon particulates is substantially restricted to a central area of the surface of the seed crystal by a separation plate disposed between the seed crystal and a source of the SiC bearing vapors. The separation plate includes a first, substantially vapor-permeable part surrounded by a second, substantially non vapor-permeable part. The grown crystals have a flat or slightly convex growth interface. Large-diameter SiC wafers fabricated from the grown crystals exhibit low lattice curvature and low densities of crystal defects, such as stacking faults, inclusions, micropipes and dislocations.

Large diameter, high quality SiC single crystals, method and apparatus

A crucible has a first resistance heater is disposed in spaced relation above the top of the crucible and a second resistance heater with a first resistive section disposed in spaced relation beneath the bottom of the crucible and with a second resistive section disposed in spaced relation around the outside of the side of the crucible. The crucible is charged with a seed crystal at the top of an interior of the crucible and a source material in the interior of the crucible in spaced relation between the seed crystal and the bottom of the crucible. Electrical power of a sufficient extent is applied to the first and second resistance heaters to create in the interior of the crucible a temperature gradient of sufficient temperature to cause the source material to sublimate and condense on the seed crystal thereby forming a growing crystal.

Growing community of inventors

Flanders, NJ, United States of America

Varatharajan Rengarajan