Patents by Inventor Devendra Kumar

Devendra Kumar 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).

  • Patent number: 6222253
    Abstract: A process for forming Silicon-On-Insulator is described incorporating the steps of ion implantation of oxygen into a silicon substrate at elevated temperature, ion implanting oxygen at a temperature below 200° C. at a lower dose to form an amorphous silicon layer, and annealing steps to form a mixture of defective single crystal silicon and polycrystalline silicon or polycrystalline silicon alone and then silicon oxide from the amorphous silicon layer to form a continuous silicon oxide layer below the surface of the silicon substrate to provide an isolated superficial layer of silicon. The invention overcomes the problem of buried isolated islands of silicon oxide forming a discontinuous buried oxide layer.
    Type: Grant
    Filed: March 21, 2000
    Date of Patent: April 24, 2001
    Assignee: International Business Machines Corporation
    Inventors: Devendra Kumar Sadana, Orin Wayne Holland
  • Patent number: 6204546
    Abstract: An SOI substrate and method of forming is described incorporating the steps of implanting oxygen under two conditions and performing two high temperature anneals at temperatures above 1250° C. and above 1300° C., respectively, at two respective oxygen concentrations. The invention overcomes the problem of high SOI substrate fabrication cost due to ion implant time and of getting high quality buried oxide (BOX) layers below a thin layer of single crystal silicon.
    Type: Grant
    Filed: May 14, 1999
    Date of Patent: March 20, 2001
    Assignee: International Business Machines Corporation
    Inventors: Peter Roitman, Devendra Kumar Sadana
  • Patent number: 6090689
    Abstract: A process for forming Silicon-On-Insulator is described incorporating the steps of ion implantation of oxygen into a silicon substrate at elevated temperature, ion implanting oxygen at a temperature below 200.degree. C. at a lower dose to form an amorphous silicon layer, and annealing steps to form a mixture of defective single crystal silicon and polycrystalline silicon or polycrystalline silicon alone and then silicon oxide from the amorphous silicon layer to form a continuous silicon oxide layer below the surface of the silicon substrate to provide an isolated superficial layer of silicon. The invention overcomes the problem of buried isolated islands of silicon oxide forming a discontinuous buried oxide layer.
    Type: Grant
    Filed: March 4, 1998
    Date of Patent: July 18, 2000
    Assignee: International Business Machines Corporation
    Inventors: Devendra Kumar Sadana, Orin Wayne Holland
  • Patent number: 6087242
    Abstract: A method of improving the bonding characteristics of a previously bonded silicon on insulator (SOI) structure is provided. The improvement in the bonding characteristics is achieved in the present invention by, optionally, forming an oxide cap layer on the silicon surface of the bonded SOI structure and then annealing either the uncapped or oxide capped structure in a slightly oxidizing ambient at temperatures greater than 1200.degree. C. Also provided herein is a method for detecting the bonding characteristics of previously bonded SOI structures. According to this aspect of the present invention, a pico-second laser pulse technique is employed to determine the bonding imperfections of previously bonded SOI structures.
    Type: Grant
    Filed: February 26, 1998
    Date of Patent: July 11, 2000
    Assignee: International Business Machines Corporation
    Inventors: Humphrey John Maris, Devendra Kumar Sadana
  • Patent number: 6043166
    Abstract: An SOI substrate and method of forming is described incorporating the steps of implanting oxygen under two conditions and performing two high temperature anneals at temperatures above 1250.degree. C. and above 1300.degree. C., respectively, at two respective oxygen concentrations. The invention overcomes the problem of high SOI substrate fabrication cost due to ion implant time and of getting high quality buried oxide (BOX) layers below a thin layer of single crystal silicon.
    Type: Grant
    Filed: October 30, 1997
    Date of Patent: March 28, 2000
    Assignees: International Business Machines Corporation, The United States of America as represented by the Department of Commerce
    Inventors: Peter Roitman, Devendra Kumar Sadana
  • Patent number: 5930643
    Abstract: A method of fabricating a defect induced buried oxide (DIBOX) region in a semiconductor substrate utilizing a first low energy implantation step to create a stable defect region; a second low energy implantation step to create an amorphous layer adjacent to the stable defect region; oxidation and, optionally, annealing, is provided. Silicon-on-insulator (SOI) materials comprising said semiconductor substrate having said DIBOX is also provided herein.
    Type: Grant
    Filed: December 22, 1997
    Date of Patent: July 27, 1999
    Assignee: International Business Machines Corporation
    Inventors: Devendra Kumar Sadana, Joel P. de Souza
  • Patent number: 5767549
    Abstract: An integrated circuit is described incorporating a substrate, a layer of insulator, a layer of silicon having raised mesas and thin regions therebetween to provide ohmic conduction between mesas, electronic devices on the mesas, and interconnection wiring. The invention overcomes the problem of a floating gate due to charge accumulation below the channel of MOS FET's.
    Type: Grant
    Filed: July 3, 1996
    Date of Patent: June 16, 1998
    Assignee: International Business Machines Corporation
    Inventors: Wei Chen, Devendra Kumar Sadana, Yuan Taur
  • Patent number: 5135604
    Abstract: Separation of laser optogalvanic signals in plasma into two components: (1) an ionization rate change component, and (2) a photoacoustic mediated component. This separation of components may be performed even when the two components overlap in time, by measuring time-resolved laser optogalvanic signals in an rf discharge plasma as the rf frequency is varied near the electrical resonance peak of the plasma and associated driving/detecting circuits. A novel spectrometer may be constructed to make these measurements. Such a spectrometer would be useful in better understanding and controlling such processes as plasma etching and plasma deposition.
    Type: Grant
    Filed: December 4, 1990
    Date of Patent: August 4, 1992
    Assignee: Board of Supervisors of Louisiana State University and Agricultural and Mechanical College
    Inventors: Devendra Kumar, Sean P. McGlynn
  • Patent number: 4748263
    Abstract: 4-Aminophenoxy cyclotriphosphazenes are reacted with maleic anhydride to produce maleamic acids which are converted to the maleimides. The maleimides are polymerized. By selection of starting materials (e.g. hexakis amino or trisaminophenoxy-trisphenoxy-cyclotriphosphazenes), selection of molar proportions of reactants, use of mixtures of anhydrides and use of dianhydrides as bridging groups a variety of maleimides and polymers are produced. The polymers have high limiting oxygen indices, high char yields and other useful heat and fire resistant properties making them useful as, for example, impregnants of fabrics.
    Type: Grant
    Filed: October 29, 1986
    Date of Patent: May 31, 1988
    Assignee: The United States of America as represented by the administrator of the National Aeronautics and Space Administration
    Inventors: Devendra Kumar, George M. Fohlen, John A. Parker
  • Patent number: 4668589
    Abstract: Aminophenoxycyclotriphosphazenes such as hexakis(4-aminophenoxy)cyclotriphosphazene and tris(4-aminophenoxy)-tris phenoxyclyclotriphosphazene are used as curing agents for epoxy resins. These 1,2-epoxy resins are selected from di- or polyepoxide-containing organic moieties of the formula (CH.sub.2 --CHO--CH.sub.2).sub.m --W--R--W--(CH.sub.2 CH--CH.sub.2 O).sub.m where R is diphenyldimethylmethane, diphenylmethane, bis(dibromophenyl)dimethylmethane, or ##STR1## W is a nitrogen or oxygen atom; and m is 1 when W is oxygen and 2 when W is nitrogen. The resins are cured thermally in stages at between about 110.degree. to 135.degree. C. for between about 1 and 10 min, then at between about 175.degree. to 185.degree. C. for between about 0.5 to 10 hr and post-cured at between about 215.degree. and 235.degree. C. for between abut 0.1 and 2 hr. These resins are useful for making fire-resistant elevated temperature stable composites, laminates (e.g.
    Type: Grant
    Filed: November 21, 1985
    Date of Patent: May 26, 1987
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Devendra Kumar, George M. Fohlen, John A. Parker
  • Patent number: 4634759
    Abstract: 4-Aminophenoxy cyclotriphosphazenes are reacted with maleic anhydride to produce maleamic acids which are converted to the maleimides. The maleimides are polymerized. By selection of starting materials (e.g. hexakis amino or trisaminophenoxy-trisphenoxy-cyclotriphosphazenes), selection of molar proportions of reactants, use of mixtures of anhydrides and use of dianhydrides as bridging groups a variety of maleimides and polymers are produced. The polymers have high limiting oxygen indices, high char yeilds and other useful heat and fire resistant properties making them useful as, for example, impregnants of fabrics.
    Type: Grant
    Filed: July 30, 1985
    Date of Patent: January 6, 1987
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Devendra Kumar, George M. Fohlen, John A. Parker
  • Patent number: 4600769
    Abstract: Novel amine terminated bisaspartimides, especially 4,4'-bis{N.sup.2 -[4-(4-aminophenoxy)phenyl]aspartimido} diphenylmethane are prepared by a Michael-type reaction of an aromatic bismaleimide and an aromatic diamine in an aprotic solvent. These bisaspartimides are thermally polymerized to yield tough, resinous polymers cross-linked through --NH-- groups. Such polymers are useful in applications requiring materials with resistance to change at elevated temperatures, e.g., as lightweight laminates with graphite cloth, molding material prepregs, adhesives and insulating material.
    Type: Grant
    Filed: May 31, 1985
    Date of Patent: July 15, 1986
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Devendra Kumar, George M. Fohlen, John A. Parker
  • Patent number: 4579782
    Abstract: Novel amine terminated bisaspartimides, especially 4,4'-bis{N.sup.2 -[4-(4-aminophenoxy)phenyl]aspartimido}diphenylmethane are prepared by a Michael-type reaction of an aromatic bismaleimide and an aromatic diamine in an aprotic solvent. These bisaspartimides are thermally polymerized to yield tough, resinous polymers cross-linked through --NH-- groups. Such polymers are useful in applications requiring materials with resistance to change at elevated temperatures, e.g., as lightweight laminates with graphite cloth, molding material prepregs, adhesives and insulating material.
    Type: Grant
    Filed: August 30, 1985
    Date of Patent: April 1, 1986
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Devendra Kumar, George M. Fohlen, John A. Parker
  • Patent number: 4550177
    Abstract: 4-Aminophenoxy cyclotriphosphazenes are reacted with maleic anhydride to produce maleamic acids which are converted to the maleimides. The maleimides are polymerized. By selection of starting materials (e.g. hexakis amino or trisaminophenoxy-trisphenoxy-cyclotriphosphazenes), selection of molar proportions of reactants, use of mixtures of anhydrides and use of dianhydrides as bridging groups a variety of maleimides and polymers are produced. The polymers have high limiting oxygen indices, high char yields and other useful heat and fire resistant properties making them useful as, for example, impregnants of fabrics.
    Type: Grant
    Filed: April 11, 1984
    Date of Patent: October 29, 1985
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Devendra Kumar, George M. Fohlen, John A. Parker