Patents by Inventor Seshadri Subbanna

Seshadri Subbanna 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: 5612255
    Abstract: A silicon quantum wire transistor. A silicon substrate is sub-etched leaving a thin ridge (.ltoreq.500 .ANG. tall by .ltoreq.500 .ANG. wide) of silicon a quantum wire, on the substrate surface. An FET may be formed from the quantum wire by depositing or growing gate oxide and depositing gate poly. After defining a gate, the source and drain are defined. Alternatively, an optically activated transistor is formed by defining an emitter and collector and providing a path for illumination to the wire.
    Type: Grant
    Filed: June 6, 1995
    Date of Patent: March 18, 1997
    Assignee: International Business Machines Corporation
    Inventors: Jonathan D. Chapple-Sokol, Seshadri Subbanna, Manu J. Tejwani
  • Patent number: 5485032
    Abstract: A programmable antifuse element comprising adjacent bodies of germanium and aluminum or aluminum allow form a low resistance connection of good mechanical and thermal properties when heated to a temperature where alloying of the aluminum and germanium occurs. Heating for the purpose of programming the antifuse element can be done by electrical resistance heating in the-germanium, which may be doped to achieve a desired resistance value, or by laser irradiation. Due to the high resistance of intrinsic or lightly doped germanium, a resistance change ratio of greater than 10,000:1 is achieved.
    Type: Grant
    Filed: December 8, 1994
    Date of Patent: January 16, 1996
    Assignee: International Business Machines Corporation
    Inventors: Dominic J. Schepis, Kris V. Srikrishnan, Seshadri Subbanna, Manu J. Tejwani
  • Patent number: 5354707
    Abstract: A semiconductor light emitting/detecting device has a first doped silicon layer, an intrinsic silicon epitaxial layer formed on the first doped silicon layer, at least one quantum dot embedded within the intrinsic silicon epitaxial layer, and a second doped silicon layer formed on the second intrinsic silicon epitaxial layer.
    Type: Grant
    Filed: November 9, 1993
    Date of Patent: October 11, 1994
    Assignee: International Business Machines Corporation
    Inventors: Jonathan D. Chapple-Sokol, Seshadri Subbanna, Manu J. Tejwani
  • Patent number: 5338698
    Abstract: An ultra-short channel field effect transistor provides a combination of a shallow junction for injection of carriers into a conduction channel and a Schottky barrier below the shallow junction with a lowered barrier height to reduce the depletion region and punch-through effects. A preferred method of fabricating this structure includes both etching and metal deposition selectively on only semiconductor material, allowing use of only a single patterning step with registration tolerances comparable to channel length while allowing extremely high integration density.
    Type: Grant
    Filed: December 18, 1992
    Date of Patent: August 16, 1994
    Assignee: International Business Machines Corporation
    Inventor: Seshadri Subbanna
  • Patent number: 5294558
    Abstract: A method of making an improved bipolar transistor and the transistor itself having a double-self-aligned device structure are disclosed. The method and the transistor device provide self-alignment of collector-base and base-emitter junctions to each other, in addition to self-alignment of the base and emitter.
    Type: Grant
    Filed: June 1, 1993
    Date of Patent: March 15, 1994
    Assignee: International Business Machines Corporation
    Inventor: Seshadri Subbanna
  • Patent number: 5293050
    Abstract: A semiconductor light emitting/detecting device has a first doped silicon layer, an intrinsic silicon epitaxial layer formed on the first doped silicon layer, at least one quantum dot embedded within the intrinsic silicon epitaxial layer, and a second doped silicon layer formed on the second intrinsic silicon epitaxial layer.
    Type: Grant
    Filed: March 25, 1993
    Date of Patent: March 8, 1994
    Assignee: International Business Machines Corporation
    Inventors: Jonathan D. Chapple-Sokol, Seshadri Subbanna, Manu J. Tejwani
  • Patent number: 5268324
    Abstract: A process is disclosed for making CMOS devices with enhanced performance PMOS FETS by integrating germanium technology into a silicon-based fabrication method. Silicon-germanium layers are selectively grown on the surfaces of oxide-isolated PFET pockets of a silicon substrate previously prepared by a conventional silicon CMOS process. A silicon cap is deposited over each Si--Ge layer and gate insulator is formed over the cap provide gate dielectric for the PFETS. Gate insulator is formed over the NFET pockets to provide gate dielectric for the NFETS. Gate structures are completed along with source and drain junctions in accordance with normal practice. Provision also is made for the additional selective growth of a second silicon-germanium layer on the surfaces of oxide-isolated NFET pockets on the same CMOS substrate to enhance the performance of the NFETS as well as that of the PFETS.
    Type: Grant
    Filed: May 27, 1992
    Date of Patent: December 7, 1993
    Assignee: International Business Machines Corporation
    Inventors: John M. Aitken, Vijay P. Kesan, Seshadri Subbanna, Manu J. Tejwani, Subramanian S. Iyer
  • Patent number: 5266504
    Abstract: A method of manufacturing a bipolar transistor by use of low temperature emitter process is disclosed. After completion of the usual base and collector formation in a vertical bipolar transistor, an emitter opening is etched in the insulator layer over the base layer at selected locations. A thin layer (less than 500 .ANG.) of in-situ doped amorphous silicon is deposited over the substrate and heated to densify for 30 to 60 minutes at about 650.degree. C. Subsequently an in-situ doped polysilicon layer of 100 to 200 nm is deposited over the amorphous Si film preferably at about 600.degree. C. Subsequently the layers are heated below 600.degree. C. for several hours to convert partially the amorphous Si into a monocrystalline emitter layer over the base regions.
    Type: Grant
    Filed: March 26, 1992
    Date of Patent: November 30, 1993
    Assignee: International Business Machines Corporation
    Inventors: Jeffrey L. Blouse, Jack O. Chu, Brian Cunningham, Jeffrey P. Gambino, Louis L. Hsu, David E. Kotecki, Seshadri Subbanna, Zu-Jean Tien
  • Patent number: 5194397
    Abstract: A method of controlling the interfacial oxygen concentration of a monocrystalline/polycrystalline emitter includes the steps of: passivating the monocrystalline silicon surface by immersing the wafer in a diluted HF acid solution; transferring the wafer into a high vacuum environment; heating the wafer to between 400.degree. and 700.degree. C.; exposing the monocrystalline silicon surface to a gas having a partial pressure of oxygen of between 10.sup.-5 to 1 Torr for between 1 and 100 minutes; and, depositing polysilicon onto the monocrystalline silicon surface.
    Type: Grant
    Filed: June 5, 1991
    Date of Patent: March 16, 1993
    Assignee: International Business Machines Corporation
    Inventors: Robert K. Cook, Ronald W. Knepper, Subodh K. Kulkarni, Russell C. Lange, Paul A. Ronsheim, Seshadri Subbanna, Manu J. Tejwani, Bob H. Yun