Patents by Inventor Robert E. Stahlbush
Robert E. Stahlbush has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 11171055Abstract: A method of cleaving includes providing a substrate. Optionally, the substrate includes ?-gallium oxide, hexagonal zinc sulfide, or magnesium selenide. The substrate includes at least one natural cleave plane and a crystallinity. The substrate is cleaved along a first natural cleave plane of the at least one natural cleave plane. The cleaving the substrate along the first natural cleave plane includes the following. A micro-crack is generated in the substrate while maintaining the crystallinity adjacent to the micro-crack by generating a plurality of phonons in the substrate, the micro-crack comprising a micro-crack direction along the first natural cleave plane. The micro-crack is propagated along the first natural cleave plane while maintaining the crystallinity adjacent to the micro-crack. Optionally, generating a micro-crack in the substrate by generating a plurality of phonons in the substrate includes generating the plurality of phonons by electron-hole recombination.Type: GrantFiled: January 30, 2020Date of Patent: November 9, 2021Assignee: The Government of the United States of America, as represented by the Secretary of the NavyInventors: Nadeemullah A. Mahadik, Robert E. Stahlbush, Marko J. Tadjer, Karl D. Hobart, Francis J. Kub
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Publication number: 20200251389Abstract: A method of cleaving includes providing a substrate. Optionally, the substrate includes ?-gallium oxide, hexagonal zinc sulfide, or magnesium selenide. The substrate includes at least one natural cleave plane and a crystallinity. The substrate is cleaved along a first natural cleave plane of the at least one natural cleave plane. The cleaving the substrate along the first natural cleave plane includes the following. A micro-crack is generated in the substrate while maintaining the crystallinity adjacent to the micro-crack by generating a plurality of phonons in the substrate, the micro-crack comprising a micro-crack direction along the first natural cleave plane. The micro-crack is propagated along the first natural cleave plane while maintaining the crystallinity adjacent to the micro-crack. Optionally, generating a micro-crack in the substrate by generating a plurality of phonons in the substrate includes generating the plurality of phonons by electron-hole recombination.Type: ApplicationFiled: January 30, 2020Publication date: August 6, 2020Inventors: NADEEMULLAH A. MAHADIK, Robert E. Stahlbush, Marko J. Tadjer, Karl D. Hobart, Francis J. Kub
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Patent number: 10403509Abstract: A method for removing existing basal plane dislocations (BPDs) from silicon carbide epilayers by using a pulsed rapid thermal annealing process where the BPDs in the epilayers were eliminated while preserving the epitaxial surface. This high temperature, high pressure method uses silicon carbide epitaxial layers with a carbon cap to protect the surface. These capped epilayers are subjected to a plurality of rapid heating and cooling cycles.Type: GrantFiled: April 6, 2015Date of Patent: September 3, 2019Assignee: The Government of the United States of America, as represented by the Secretary of the NavyInventors: Marko J. Tadjer, Boris N. Feigelson, Nadeemullah A. Mahadik, Robert E. Stahlbush, Eugene A. Imhoff, Jordan Greenlee
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Patent number: 10256094Abstract: A method of: providing an off-axis 4H—SiC substrate, and etching the surface of the substrate with hydrogen or an inert gas.Type: GrantFiled: March 11, 2014Date of Patent: April 9, 2019Assignee: The Government of the United States of America, as represented by the Secretary of the NavyInventors: Rachael L. Myers-Ward, David Kurt Gaskill, Charles R. Eddy, Jr., Robert E. Stahlbush, Nadeemmullah A. Mahadik, Virginia D. Wheeler
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Patent number: 10256090Abstract: A method of: providing an off-axis silicon carbide substrate, and etching the surface of the substrate with a dry gas, hydrogen, or an inert gas.Type: GrantFiled: March 11, 2014Date of Patent: April 9, 2019Assignee: The United States of America, as represented by the Secretary of the NavyInventors: Rachael L. Myers-Ward, David Kurt Gaskill, Charles R. Eddy, Jr., Robert E. Stahlbush, Nadeemmullah A. Mahadik, Virginia D. Wheeler
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Patent number: 10020366Abstract: A method and device including adding a protective layer on the surface of a substrate, annealing the substrate at a temperature approximately greater or equal to 1850° C., removing the protective layer from the surface of the substrate after the annealing, and growing a first epilayer on the substrate after the removing of the protective layer, wherein the first epilayer is grown without attempting to prevent the basal plane dislocations to propagate in the first epilayer when growing the first epilayer, and wherein the first epilayer is free of the basal plane dislocations.Type: GrantFiled: September 22, 2016Date of Patent: July 10, 2018Assignee: The United States of America, as represented by the Secretary of the NavyInventors: Nadeemullah A. Mahadik, Robert E. Stahlbush, Eugene A. Imhoff, Marko J. Tadjer
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Publication number: 20170092724Abstract: A method and device including adding a protective layer on the surface of a substrate, annealing the substrate at a temperature approximately greater or equal to 1850° C., removing the protective layer from the surface of the substrate after the annealing, and growing a first epilayer on the substrate after the removing of the protective layer, wherein the first epilayer is grown without attempting to prevent the basal plane dislocations to propagate in the first epilayer when growing the first epilayer, and wherein the first epilayer is free of the basal plane dislocations.Type: ApplicationFiled: September 22, 2016Publication date: March 30, 2017Inventors: Nadeemullah A. Mahadik, Robert E. Stahlbush, Eugene A. Imhoff, Marko J. Tadjer
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Patent number: 9464366Abstract: A method for reducing/eliminating basal plane dislocations from SiC epilayers is disclosed. An article having: an off-axis SiC substrate having an off-axis angle of no more than 6°; and a SiC epitaxial layer grown on the substrate. The epitaxial layer has no more than 2 basal plane dislocations per cm2 at the surface of the epitaxial layer. A method of growing an epitaxial SiC layer on an off-axis SiC substrate by: flowing a silicon source gas, a carbon source gas, and a carrier gas into a growth chamber under growth conditions to epitaxially grow SiC on the substrate in the growth chamber. The substrate has an off-axis angle of no more than 6°. The growth conditions include: a growth temperature of 1530-1650° C.; a pressure of 50-125 mbar; a C/H gas flow ratio of 9.38×10?5-1.5×10?3; a C/Si ratio of 0.5-3; a carbon source gas flow rate during ramp to growth temperature from 0 to 15 sccm; and an electron or hole concentration of 1013-1019/cm3.Type: GrantFiled: August 20, 2010Date of Patent: October 11, 2016Assignee: The United States of America, as represented by the Secretary of the NavyInventors: Rachael L Myers-Ward, David Kurt Gaskill, Brenda L VanMil, Robert E Stahlbush, Charles R. Eddy, Jr.
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Publication number: 20160056065Abstract: A method and apparatus wherein a photoluminescence in a semiconductor wafer is excited using an ultraviolet light source. A plurality of partial raw images of the photoluminescence is generated. The plurality of partial raw images includes at least one equipment-generated artifact The at least one equipment-generated artifact is removed from the cluster of partial raw images using the equipment-generated artifact image to generate a cluster of partial processed images. A plurality of clusters of partial processed images is generated. The plurality of clusters of partial processed images are aligned and combined to generate a wafer image tree of the at least one equipment-generated artifact.Type: ApplicationFiled: August 14, 2015Publication date: February 25, 2016Inventor: Robert E. Stahlbush
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Publication number: 20150287613Abstract: A method for removing existing basal plane dislocations (BPDs) from silicon carbide epilayers by using a pulsed rapid thermal annealing process where the BPDs in the epilayers were eliminated while preserving the epitaxial surface. This high temperature, high pressure method uses silicon carbide epitaxial layers with a carbon cap to protect the surface. These capped epilayers are subjected to a plurality of rapid heating and cooling cycles.Type: ApplicationFiled: April 6, 2015Publication date: October 8, 2015Inventors: Marko J. Tadjer, Boris N. Feigelson, Nadeemullah A. Mahadik, Robert E. Stahlbush, Eugene A. Imhoff, Jordan Greenlee
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Patent number: 9129799Abstract: A method to remove basal plane dislocations in post growth silicon carbide epitaxial layers by capping post growth silicon carbide epilayers with a graphite cap and annealing the capped silicon carbon epilayers at a temperature of 1750° C. or greater with a nitrogen overpressure of 60-110 psi, wherein basal plane dislocations in the epilayers are removed while surface morphology is preserved. Also disclosed is the related silicon carbide substrate material made by this method.Type: GrantFiled: September 26, 2014Date of Patent: September 8, 2015Assignee: The United States of America, as represented by the Secretary of the NavyInventors: Nadeemullah A. Mahadik, Robert E. Stahlbush, Marko J. Tadjer, Eugene A. Imhoff, Boris N. Feigelson
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Publication number: 20150155166Abstract: A method to remove basal plane dislocations in post growth silicon carbide epitaxial layers by capping post growth silicon carbide epilayers with a graphite cap and annealing the capped silicon carbon epilayers at a temperature of 1750° C. or greater with a nitrogen overpressure of 60-110 psi, wherein basal plane dislocations in the epilayers are removed while surface morphology is preserved. Also disclosed is the related silicon carbide substrate material made by this method.Type: ApplicationFiled: September 26, 2014Publication date: June 4, 2015Inventors: Nadeemullah A. Mahadik, Robert E. Stahlbush, Marko J. Tadjer, Eugene A. Imhoff, Boris N. Feigelson
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Publication number: 20140190399Abstract: A method of: providing an off-axis silicon carbide substrate, and etching the surface of the substrate with a dry gas, hydrogen, or an inert gas.Type: ApplicationFiled: March 11, 2014Publication date: July 10, 2014Applicant: The Government of the United States of America, as represented by the Secretary of the NavyInventors: Rachael L. Myers-Ward, David Kurt Gaskill, Charles R. Eddy, JR., Robert E. Stahlbush, Nadeemmullah A. Mahadik, Virginia D. Wheeler
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Publication number: 20140193965Abstract: A method of: providing an off-axis 4H—SiC substrate, and etching the surface of the substrate with hydrogen or an inert gas.Type: ApplicationFiled: March 11, 2014Publication date: July 10, 2014Applicant: The Government of the United States of America, as represented by the Secretary of the NavyInventors: Rachael L. Myers-Ward, David Kurt Gaskill, Charles R. Eddy, JR., Robert E. Stahlbush, Nadeemmullah A. Mahadik, Virginia D. Wheeler
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Patent number: 8652255Abstract: A method of: flowing a silicon source gas, a carbon source gas, and a carrier gas into a growth chamber under growth conditions to epitaxial grow silicon carbide on a wafer in the growth chamber; stopping or reducing the flow of the silicon source gas to interrupt the silicon carbide growth and maintaining the flow of the carrier gas while maintaining an elevated temperature in the growth chamber for a period of time; and resuming the flow of the silicon source gas to reinitiate silicon carbide growth. The wafer remains in the growth chamber throughout the method.Type: GrantFiled: October 9, 2008Date of Patent: February 18, 2014Assignee: The United States of America, as represented by the Secretary of the NavyInventors: Robert E Stahlbush, Brenda L VanMil, Kok-Keong Lew, Rachael L Myers-Ward, David Kurt Gaskill, Charles R. Eddy, Jr.
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Patent number: 7915143Abstract: A method of reversing Shockley stacking fault expansion includes providing a bipolar or a unipolar SiC device exhibiting forward voltage drift caused by Shockley stacking fault nucleation and expansion. The SiC device is heated to a temperature above 150° C. A current is passed via forward bias operation through the SiC device sufficient to induce at least a partial recovery of the forward bias drift.Type: GrantFiled: April 30, 2009Date of Patent: March 29, 2011Assignee: The United States of America as represented by the Secretary of the NavyInventors: Joshua D. Caldwell, Robert E Stahlbush, Karl D Hobart, Marko J Tadjer, Orest J Glembocki
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Publication number: 20110045281Abstract: A method for reducing/eliminating basal plane dislocations from SiC epilayers is disclosed. An article having: an off-axis SiC substrate having an off-axis angle of no more than 6°; and a SiC epitaxial layer grown on the substrate. The epitaxial layer has no more than 2 basal plane dislocations per cm2 at the surface of the epitaxial layer. A method of growing an epitaxial SiC layer on an off-axis SiC substrate by: flowing a silicon source gas, a carbon source gas, and a carrier gas into a growth chamber under growth conditions to epitaxially grow SiC on the substrate in the growth chamber. The substrate has an off-axis angle of no more than 6°. The growth conditions include: a growth temperature of 1530-1650° C.; a pressure of 50-125 mbar; a C/H gas flow ratio of 9.38×10?5-1.5×10?3; a C/Si ratio of 0.5-3; a carbon source gas flow rate during ramp to growth temperature from 0 to 15 sccm; and an electron or hole concentration of 1013-1019/cm3.Type: ApplicationFiled: August 20, 2010Publication date: February 24, 2011Applicant: The Government of the United States of America, as represented by the Secretary of the NavyInventors: Rachael L. Myers-Ward, David Kurt Gaskill, Brenda L. VanMil, Robert E. Stahlbush, Charles R. Eddy, JR.
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Publication number: 20090273390Abstract: A method of reversing Shockley stacking fault expansion includes providing a bipolar or a unipolar SiC device exhibiting forward voltage drift caused by Shockley stacking fault nucleation and expansion. The SiC device is heated to a temperature above 150° C. A current is passed via forward bias operation through the SiC device sufficient to induce at least a partial recovery of the forward bias drift.Type: ApplicationFiled: April 30, 2009Publication date: November 5, 2009Inventors: JOSHUA D. CALDWELL, Robert E. Stahlbush, Karl D. Hobart, Marko J. Tadjer, Orest J. Glembocki
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Publication number: 20090114148Abstract: A method of: flowing a silicon source gas, a carbon source gas, and a carrier gas into a growth chamber under growth conditions to epitaxial grow silicon carbide on a wafer in the growth chamber; stopping or reducing the flow of the silicon source gas to interrupt the silicon carbide growth and maintaining the flow of the carrier gas while maintaining an elevated temperature in the growth chamber for a period of time; and resuming the flow of the silicon source gas to reinitiate silicon carbide growth. The wafer remains in the growth chamber throughout the method.Type: ApplicationFiled: October 9, 2008Publication date: May 7, 2009Applicant: The Government of the United States of America, as represented by the Secretary of the NavyInventors: Robert E. Stahlbush, Brenda L. VanMil, Kok-Keong Lew, Rachael L. Myers-Ward, David Kurt Gaskill, Charles R. Eddy, JR.
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Patent number: 4396769Abstract: Crystalline, non-dusting bis(2,2,6,6-tetramethylpiperidin-4-yl) sebacate is made by heating the sebacate ester to a temperature above its melting point and then slowly cooling the melt with agitation to form the product in a crystalline, non-dusting form. This ester, also known as TINUVIN 770, is a valuable commercial light stabilizer for a myriad of substrates.Type: GrantFiled: February 11, 1982Date of Patent: August 2, 1983Assignee: Ciba-Geigy CorporationInventors: Anibal L. Ferreira, Robert E. Stahlbush