Abstract: 4H SIC epiwafers with thickness of 50-100 ?m are grown on 4° off-axis substrates. Surface morphological defect density in the range of 2-6 cm?2 is obtained from inspection of the epiwafers. Consistent carrier lifetime in the range of 2-3 ?s has been obtained on these epiwafers. Very low BPD density has been confirmed in the epiwafers with BPD density down to below 10 cm?2. Epitaxial wafers with thickness of 50-100 ?m have been used to fabricate diodes. High voltage testing has demonstrated blocking voltages near the theoretical values for 4H-SiC. Blocking voltage as high as 8 kV has been achieved in devices fabricated on 50 ?m thick epitaxial films, and blocking voltage as high as 10 kV has been obtained in devices fabricated on 80 ?m thick films. Failure analysis confirmed triangle defects, which form from surface damage or particles present during epitaxy, are killer defects and cause the device to fail in reverse bias operation.

Abstract: Methods for manufacturing silicon carbide wafers having superior specifications for bow, warp, total thickness variation (TTV), local thickness variation (LTV), and site front side least squares focal plane range (SFQR). The resulting SiC wafer has a mirror-like surface that is fit for epitaxial deposition of SiC. The specifications for bow, warp, total thickness variation (TTV), local thickness variation (LTV), and site front side least squares focal plane range (SFQR) of the wafer are preserved following the addition of the epitaxy layer.

Abstract: Methods for manufacturing silicon carbide wafers having superior specifications for bow, warp, total thickness variation (TTV), local thickness variation (LTV), and site front side least squares focal plane range (SFQR). The resulting SiC wafer has a mirror-like surface that is fit for epitaxial deposition of SiC. The specifications for bow, warp, total thickness variation (TTV), local thickness variation (LTV), and site front side least squares focal plane range (SFQR) of the wafer are preserved following the addition of the epitaxy layer.

Abstract: Methods for manufacturing silicon carbide wafers having superior specifications for bow, warp, total thickness variation (TTV), local thickness variation (LTV), and site front side least squares focal plane range (SFQR). The resulting SiC wafer has a mirror-like surface that is fit for epitaxial deposition of SiC. The specifications for bow, warp, total thickness variation (TTV), local thickness variation (LTV), and site front side least squares focal plane range (SFQR) of the wafer are preserved following the addition of the epitaxy layer.

Abstract: A method of forming an SiC crystal including placing a seed crystal of SiC in an insulated graphite container; placing a source of Si and C atoms in the insulated graphite container, where the source of Si and C atoms is for transport to the seed crystal to grow the SiC crystal; placing the container into the furnace; heating a furnace to a temperature from about 2,000° C. to about 2,500° C.; evacuating the furnace to a pressure from about 0.1 Torr and about 100 Torr; filling the furnace with an inert gas; and introducing dopant gas into the furnace with a controlled flow so as to form a plurality of stratified layers wherein each layer has dopant concentration different from a layer directly below and a layer directly above it. A 4H-SiC crystal made by the method. A 4H-SiC substrate cut from the SiC crystal made from the method.

Abstract: 4H SiC epiwafers with thickness of 50-100 ?m are grown on 4° off-axis substrates. Surface morphological defect density in the range of 2-6 cm?2 is obtained from inspection of the epiwafers. Consistent carrier lifetime in the range of 2-3 ?s has been obtained on these epiwafers. Very low BPD density has been confirmed in the epiwafers with BPD density down to below 10 cm?2. Epitaxial wafers with thickness of 50-100 ?m have been used to fabricate diodes. High voltage testing has demonstrated blocking voltages near the theoretical values for 4H-SiC. Blocking voltage as high as 8 kV has been achieved in devices fabricated on 50 ?m thick epitaxial films, and blocking voltage as high as 10 kV has been obtained in devices fabricated on 80 ?m thick films. Failure analysis confirmed triangle defects, which form from surface damage or particles present during epitaxy, are killer defects and cause the device to fail in reverse bias operation.

Abstract: A method of forming an SiC crystal including placing in an insulated graphite container a seed crystal of SiC, and supporting the seed crystal on a shelf, wherein cushion rings contact the seed crystal on a periphery of top and bottom surfaces of the seed crystal, and where the graphite container does not contact a side surface of the seed crystal; placing a source of Si and C atoms in the insulated graphite container, where the source of Si and C atoms is for transport to the seed crystal to grow the SiC crystal; placing the graphite container in a furnace; heating the furnace; evacuating the furnace; filling the furnace with an inert gas; and maintaining the furnace to support crystal growth to thereby form the SiC crystal.

Abstract: A method of forming an SiC crystal, the method including: placing a SiC seed in a growth vessel, heating the growth vessel, and evacuating the growth vessel, wherein the seed is levitated as a result of a temperature and pressure gradient, and gas flows from a growth face of the seed, around the edge of the seed, and into a volume behind the seed, which is pumped by a vacuum system.

Abstract: A method of forming an SiC crystal including placing a seed crystal of SiC in an insulated graphite container; placing a source of Si and C atoms in the insulated graphite container, where the source of Si and C atoms is for transport to the seed crystal to grow the SiC crystal; placing the container into the furnace; heating a furnace to a temperature from about 2,000° C. to about 2,500° C.; evacuating the furnace to a pressure from about 0.1 Torr and about 100 Torr; filling the furnace with an inert gas; and introducing dopant gas into the furnace with a controlled flow so as to form a plurality of stratified layers wherein each layer has dopant concentration different from a layer directly below and a layer directly above it. A 4H-SiC crystal made by the method. A 4H-SiC substrate cut from the SiC crystal made from the method.

Abstract: This invention relates to a method for depositing silicon carbide material onto a substrate such that the resulting substrate has a carrier lifetime of 0.5-1000 microseconds, the method comprising a. introducing a gas mixture comprising a chlorosilane gas, a carbon-containing gas, and hydrogen gas into a reaction chamber containing a substrate; and b. heating the substrate to a temperature of greater than 1000° C. but less than 2000° C.; with the proviso that the pressure within the reaction chamber is maintained in the range of 0.1 to 760 torr. This invention also relates to a method for depositing silicon carbide material onto a substrate such that the resulting substrate has a carrier lifetime of 0.5-1000 microseconds, the method comprising a. introducing a gas mixture comprising a non-chlorinated silicon-containing gas, hydrogen chloride, a carbon-containing gas, and hydrogen gas into a reaction chamber containing a substrate; and b. heating the substrate to a temperature of greater than 1000° C.

Abstract: This invention relates to a method for the manufacture of monolithic ingot of silicon carbide comprising: i) introducing a mixture comprising polysilicon metal chips and carbon powder into a cylindrical reaction cell having a lid; ii) sealing the cylindrical reaction cell of i); iii) introducing the cylindrical reaction cell of ii) into a vacuum furnace; iv) evacuating the furnace of iii); v) filling the furnace of iv) with a gas mixture which is substantially inert gas to near atmospheric pressure; vi) heating the cylindrical reaction cell in the furnace of v) to a temperature of from 1600 to 2500° C.; vii) reducing the pressure in the cylindrical reaction cell of vi) to less than 50 torr but not less than 0.05 torr; and viii) allowing for substantial sublimation and condensation of the vapors on the inside of the lid of the cylindrical reaction cell of vii).

Abstract: Methods for manufacturing silicon carbide wafers having superior specifications for bow, warp, total thickness variation (TTV), local thickness variation (LTV), and site front side least squares focal plane range (SFQR). The resulting SiC wafer has a mirror-like surface that is fit for epitaxial deposition of SiC. The specifications for bow, warp, total thickness variation (TTV), local thickness variation (LTV), and site front side least squares focal plane range (SFQR) of the wafer are preserved following the addition of the epitaxy layer.

Abstract: 4H SiC epiwafers with thickness of 50-100 ?m are grown on 4° off-axis substrates. Surface morphological defect density in the range of 2-6 cm?2 is obtained from inspection of the epiwafers. Consistent carrier lifetime in the range of 2-3 ?s has been obtained on these epiwafers. Very low BPD density has been confirmed in the epiwafers with BPD density down to below 10 cm?2. Epitaxial wafers with thickness of 50-100 ?m have been used to fabricate diodes. High voltage testing has demonstrated blocking voltages near the theoretical values for 4H-SiC. Blocking voltage as high as 8 kV has been achieved in devices fabricated on 50 ?m thick epitaxial films, and blocking voltage as high as 10 kV has been obtained in devices fabricated on 80 ?m thick films. Failure analysis confirmed triangle defects, which form from surface damage or particles present during epitaxy, are killer defects and cause the device to fail in reverse bias operation.

Abstract: A method of reducing memory effects during an epitaxial growth process is provided in which a gas mixture comprising hydrogen gas and a halogen-containing gas is used to flush the CVD reaction chamber between growth steps.

Abstract: This invention relates to a method for the manufacture of monolithic ingot of silicon carbide comprising: i) introducing a mixture comprising polysilicon metal chips and carbon powder into a cylindrical reaction cell having a lid; ii) sealing the cylindrical reaction cell of i); iii) introducing the cylindrical reaction cell of ii) into a vacuum furnace; iv) evacuating the furnace of iii); v) filling the furnace of iv) with a gas mixture which is substantially inert gas to near atmospheric pressure; vi) heating the cylindrical reaction cell in the furnace of v) to a temperature of from 1600 to 2500° C.; vii) reducing the pressure in the cylindrical reaction cell of vi) to less than 50 torr but not less than 0.05 torr; and viii) allowing for substantial sublimation and condensation of the vapors on the inside of the lid of the cylindrical reaction cell of vii).

Abstract: A method of reducing memory effects during an epitaxial growth process is provided in which a gas mixture comprising hydrogen gas and a halogen-containing gas is used to flush the CVD reaction chamber between growth steps.

Abstract: The present invention provides method and process for forming a barrier layer on a flexible substrate. The continuous roll-to-roll method includes providing a substrate to a processing chamber using at least one roller configured to guide the substrate through the processing chamber. The process includes depositing a barrier layer adjacent the substrate by exposing at least one portion of the substrate that is within the processing chamber to plasma comprising a silicon-and-carbon containing precursor gas. The present invention is further directed to a coated flexible substrates comprising a barrier layer based on the structural unit SiC:H. The barrier layer possesses high density and low porosity. Still further, the barrier layer exhibits low water vapor transmission rate (WVTR) in the range of 10?2-10?3 g.m?2d?1 and is appropriate for very low permeability applications.

Abstract: Coated substrates containing at least one barrier layer comprising hydrogenated silicon oxycarbide having a density of at least 1.6 g/cm3 and at least one barrier layer selected from aluminum, aluminum oxide, aluminum nitride, aluminum oxynitride, titanium, titanium oxide, titanium nitride, and titanium oxynitride.

Abstract: This invention relates to a method for depositing silicon carbide material onto a substrate such that the resulting substrate has a carrier lifetime of 0.5-1000 microseconds, the method comprising a. introducing a gas mixture comprising a chlorosilane gas, a carbon-containing gas, and hydrogen gas into a reaction chamber containing a substrate; and b. heating the substrate to a temperature of greater than 1000° C. but less than 2000° C.; with the proviso that the pressure within the reaction chamber is maintained in the range of 0.1 to 760 torr. This invention also relates to a method for depositing silicon carbide material onto a substrate such that the resulting substrate has a carrier lifetime of 0.5-1000 microseconds, the method comprising a. introducing a gas mixture comprising a non-chlorinated silicon-containing gas, hydrogen chloride, a carbon-containing gas, and hydrogen gas into a reaction chamber containing a substrate; and b. heating the substrate to a temperature of greater than 1000° C.

Abstract: Coated substrates containing a barrier layer comprising hydrogenated silicon oxycarbide having a density of at least 1.6 g/cm3 and methods of preparing the coated substrates.