Patents by Inventor Ravi Droopad
Ravi Droopad 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: 9390913Abstract: A semiconductor/dielectric interface having reduced interface trap density and a method of manufacturing the interface are disclosed. In an exemplary embodiment, the method comprises receiving a substrate, the substrate containing a semiconductor; preparing a surface of the substrate; forming a termination layer bonded to the semiconductor at the surface of the substrate; and depositing a dielectric layer above the termination layer, the depositing configured to not disrupt the termination layer. The forming of the termination layer may be configured to produce the termination layer having a single layer of oxygen atoms between the substrate and the dielectric layer.Type: GrantFiled: February 22, 2013Date of Patent: July 12, 2016Assignee: Taiwan Semiconductor Manufacturing Company, Ltd.Inventors: Chien-Hsun Wang, Shih Wei Wang, Ravi Droopad, Gerben Doombos, Georgios Vellianitis, Matthias Passlack
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Publication number: 20140239418Abstract: A semiconductor/dielectric interface having reduced interface trap density and a method of manufacturing the interface are disclosed. In an exemplary embodiment, the method comprises receiving a substrate, the substrate containing a semiconductor; preparing a surface of the substrate; forming a termination layer bonded to the semiconductor at the surface of the substrate; and depositing a dielectric layer above the termination layer, the depositing configured to not disrupt the termination layer. The forming of the termination layer may be configured to produce the termination layer having a single layer of oxygen atoms between the substrate and the dielectric layer.Type: ApplicationFiled: February 22, 2013Publication date: August 28, 2014Applicant: Taiwan Semiconductor Manufacturing Company, Ltd.Inventors: Chien-Hsun Wang, Shih Wei Wang, Ravi Droopad, Gerben Doombos, Georgios Vellianitis, Matthias Passlack
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Patent number: 6113690Abstract: A method of preparing crystalline alkaline earth metal oxides on a Si substrate wherein a Si substrate with amorphous silicon dioxide on a surface is provided. The substrate is heated to a temperature in a range of 700.degree. C. to 800.degree. C. and exposed to a beam of alkaline earth metal(s) in a molecular beam epitaxy chamber at a pressure within approximately a 10.sup.-9 -10.sup.-10 Torr range. During the molecular beam epitaxy the surface is monitored by RHEED technique to determine a conversion of the amorphous silicon dioxide to a crystalline alkaline earth metal oxide. Once the alkaline earth metal oxide is formed, additional layers of material, e.g. additional thickness of an alkaline earth metal oxide, single crystal ferroelectrics or high dielectric constant oxides on silicon for non-volatile and high density memory device applications.Type: GrantFiled: June 8, 1998Date of Patent: September 5, 2000Assignee: Motorola, Inc.Inventors: Zhiyi Jimmy Yu, Jerald A. Hallmark, Jonathan K. Abrokwah, Corey D. Overgaard, Ravi Droopad
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Patent number: 6110840Abstract: A method of passivating the surface of a Si wafer is disclosed including the steps of cleaning the surface of the Si wafer and depositing an alkaline earth metal on the clean surface at a wafer temperature in a range of approximately 400.degree. C. to 750.degree. C. The surface is monitored during deposition to detect a (4.times.2) surface reconstruction pattern indicating approximately a one-quarter monolayer of alkaline earth metal is formed. The wafer is annealed at a temperature in a range of 800.degree. C. to 900.degree. C. until the alkaline earth metal forms an alkaline earth metal silicide with a (2.times.1) surface pattern on the surface.Type: GrantFiled: February 17, 1998Date of Patent: August 29, 2000Assignee: Motorola, Inc.Inventors: Zhiyi Jimmy Yu, Corey D. Overgaard, Ravi Droopad, Jonathan K. Abrokwah, Jerald A. Hallmark
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Patent number: 6030453Abstract: A production process for protecting the surface of compound semiconductor wafers includes providing a multi-wafer epitaxial production system with a transfer and load module, a III-V growth chamber and an insulator chamber. The wafer is placed in the transfer and load module and the pressure is reduced to .ltoreq.10.sup.-10 Torr, after which the wafer is moved to the III-V growth chamber and layers of compound semiconductor material are epitaxially grown on the surface of the wafer.Type: GrantFiled: March 4, 1997Date of Patent: February 29, 2000Assignee: Motorola, Inc.Inventors: Matthias Passlack, Jonathan K. Abrokwah, Ravi Droopad, Corey D. Overgaard
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Patent number: 5937285Abstract: A method of fabricating submicron HFETs includes forming a buffered substrate structure with a supporting substrate of GaAs, a portion of low temperature AlGaAs grown on the supporting substrate at a temperature of approximately 300.degree. C., a layer of low temperature GaAs grown on the portion AlGaAs layer at a temperature of 200.degree. C., a layer of low temperature AlGaAs grown on the GaAs layer at a temperature of 400.degree. C., and a buffer layer of undoped GaAs grown on the second AlGaAs layer. Complementary pairs of HFETs can be formed on the buffered substrate structure, since the structure supports the operation of p and n type transistors equally well.Type: GrantFiled: May 23, 1997Date of Patent: August 10, 1999Assignee: Motorola, Inc.Inventors: Jonathan K. Abrokwah, Ravi Droopad, Corey D. Overgaard, Brian Bowers, Michael P. LaMacchia, Bruce A. Bernhardt
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Patent number: 5907792Abstract: A method of forming a silicon nitride layer or film on a semiconductor wafer structure includes forming a silicon nitride layer on the surface of a wafer structure using a molecular beam of high purity elemental Si and an atomic beam of high purity nitrogen. In a preferred embodiment, a III-V compound semiconductor wafer structure is heated in an ultra high vacuum system to a temperature below the decomposition temperature of said compound semiconductor wafer structure and a silicon nitride layer is formed using a molecular beam of Si provided by either thermal evaporation or electron beam evaporation, and an atomic nitrogen beam provided by either RF or microwave plasma discharge.Type: GrantFiled: August 25, 1997Date of Patent: May 25, 1999Assignee: Motorola,Inc.Inventors: Ravi Droopad, Jonathan K. Abrokwah, Matthias Passlack, Zhiyi Jimmy Yu
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Patent number: 5904553Abstract: A method of fabricating a gate quality oxide-compound semiconductor structure includes forming an insulating Ga.sub.2 O.sub.3 layer on the surface of a compound semiconductor wafer structure by a supersonic gas jet containing gallium oxide molecules and oxygen. In a preferred embodiment, a III-V compound semiconductor wafer structure with an atomically ordered and chemically clean semiconductor surface is transferred from a semiconductor growth chamber into an insulator deposition chamber via an ultra high vacuum preparation chamber. Ga.sub.2 O.sub.3 deposition onto the surface of the wafer structure is initiated by a supersonic gas jet pulse and proceeds via optimization of pulse duration, speed of gas jet, mole fraction of gallium oxide molecules and oxygen atoms, and plasma energy.Type: GrantFiled: August 25, 1997Date of Patent: May 18, 1999Assignee: Motorola, Inc.Inventors: Matthias Passlack, Jonathan K. Abrokwah, Ravi Droopad, Brian Bowers