Patents by Inventor Robert L. Virkus

Robert L. Virkus 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: 5316957
    Abstract: Disclosed is a scaled, self aligned, bipolar transistor and a method of fabrication which is compatible with MOSFET device structures. A transistor intrinsic base region is formed in the face of an isolated epitaxial region and polysilicon is deposited, patterned and etched to form emitter regions. An oxide cap and first sidewall oxide spacers are formed on the polysilicon emitters and the single crystal silicon is etched using the oxide covered emitters as a mask to form recessed regions in the epitaxial layer. The extrinsic base region is then formed adjacent at least one side of the base by implanting appropriate dopants into one of the recessed regions. A second sidewall oxide spacer is then formed on the vertical base emitter structure and a heavily doped collector contact region is formed by implanting appropriate dopants into another one of the recessed silicon regions.
    Type: Grant
    Filed: June 30, 1993
    Date of Patent: May 31, 1994
    Assignee: Texas Instruments Incorporated
    Inventors: David B. Spratt, Robert L. Virkus, Robert H. Eklund, Eldon J. Zorinsky
  • Patent number: 5075241
    Abstract: Disclosed is a scaled, self aligned, bipolar transistor and a method of fabrication which is compatible with MOSFET device structures. A transistor intrinsic base region is formed in the face of an isolated epitaxial region and polysilicon is deposited, patterned and etched to form emitter regions. An oxide cap and first sidewall oxide spacers are formed on the polysilicon emitters and the single crystal silicon is etched using the oxide covered emitters as a mask to form recessed regions in the epitaxial layer. The extrinsic base region is then formed adjacent at least one side of the base by implanting appropriate dopants into one of the recessed regions. A second sidewall oxide spacer is then formed on the vertical base emitter structure and a heavily doped collector contact region is formed by implanting appropriate dopants into another one of the recessed silicon regions.
    Type: Grant
    Filed: June 22, 1990
    Date of Patent: December 24, 1991
    Assignee: Texas Instruments Incorporated
    Inventors: David B. Spratt, Robert L. Virkus, Robert H. Eklund, Eldon J. Zorinsky
  • Patent number: 5019525
    Abstract: A method for forming a self-aligned horizontal transistor includes the step of first defining a narrow base contact on an isolated N-tank (10) to define a first reference edge (41). A layer of sidewall oxide (40) is then disposed on the vertical wall of the base contact (34) to define a second reference edge (42). An emitter well (44) and a collector well (46) are then defined on either side of the contact with the vertical wall of the emitter well (44) aligned with the reference edge (42). A dopant material is then disposed adjacent the reference edge (42) and the dopant diffused into the substrate from a lateral direction to form a P-type base region (58) with a graded impurity profile. N-doped regions (64) and (66) are then formed in the emitter and collector wells to form the emitter and collector of the transistor.
    Type: Grant
    Filed: July 5, 1990
    Date of Patent: May 28, 1991
    Assignee: Texas Instruments Incorporated
    Inventors: Robert L. Virkus, David B. Spratt, Eldon J. Zorinsky
  • Patent number: 5001541
    Abstract: An advanced electromigration resistant lead (34) is formed over an insulator layer (36). The lead (34) is processed from a metallic film having a known grain size. A rapid thermal anneal is conducted to increase the grain size and to reduce the number of triple points. The lead (34) is also engineered to have rounded edges (40) rather than sharp edges. The rounded edges (40) reduce the amount of stress in the lead (34) and help further reduce the effects of electromigration.
    Type: Grant
    Filed: March 22, 1989
    Date of Patent: March 19, 1991
    Assignee: Texas Instruments Incorporated
    Inventors: Robert L. Virkus, Hoang H. Hoang
  • Patent number: 4985744
    Abstract: Disclosed is a scaled, self aligned, bipolar transistor and a method of fabrication which is compatible with MOSFET device structures. A transistor intrinsic base region is formed in the face of an isolated epitaxial region and polysilicon is deposited, patterned and etched to form emitter regions. An oxide cap and first sidewall oxide spacers are formed on the polysilicon emitters and the single crystal silicon is etched using the oxide covered emitters as a mask to form recessed regions in the epitaxial layer. The extrinsic base region is then formed adjacent at least one side of the base by implanting appropriate dopants into one of the recessed regions. A second sidewall oxide spacer is then formed on the vertical base emitter structure and a heavily doped collector contact region is formed by implanting appropriate dopants into another one of the recessed silicon regions.
    Type: Grant
    Filed: September 21, 1989
    Date of Patent: January 15, 1991
    Assignee: Texas Instruments Incorporated
    Inventors: David B. Spratt, Robert L. Virkus, Robert H. Eklund, Eldon J. Zorinsky
  • Patent number: 4982263
    Abstract: A silicon on insulator semiconductor structure employs a strain layer fabricated of an electrically inactive material. The strain layer comprises silicon with a germanium additive to produce a sublayer exhibiting a low breakdown voltage and thus effective for selective anodization.
    Type: Grant
    Filed: March 10, 1989
    Date of Patent: January 1, 1991
    Assignee: Texas Instruments Incorporated
    Inventors: David B. Spratt, Eldon J. Zorinsky, Robert L. Virkus, Kenneth E. Bean, Richard L. Yeakley
  • Patent number: 4897703
    Abstract: Disclosed is a scaled, self aligned, bipolar transistor and a method of fabrication which is compatible with MOSFET device structures. A transistor intrinsic base region is formed in the face of an isolated epitaxial region and polysilicon is deposited, patterned and etched to form emitter regions. An oxide cap and first sidewall oxide spacers are formed on the polysilicon emitters and the single crystal silicon is etched using the oxide covered emitters as a mask to form recessed regions in the epitaxial layer. The extrinsic base region is then formed adjacent at least one side of the base by implanting appropriate dopants into one of the recessed regions. A second sidewall oxide spacer is then formed on the vertical base emitter structure and a heavily doped collector contact region is formed by implanting appropriate dopants into another one of the recessed silicon regions.
    Type: Grant
    Filed: January 29, 1988
    Date of Patent: January 30, 1990
    Assignee: Texas Instruments Incorporated
    Inventors: David B. Spratt, Robert L. Virkus, Robert H. Eklund, Eldon J. Zorinsky
  • Patent number: 4849370
    Abstract: A silicon on insulator semiconductor structure employs a strain layer fabricated of an electrically inactive material. The strain layer comprises silicon with a germanium additive to produce a sublayer exhibiting a low breakdown voltage and thus effective for selective anodization.
    Type: Grant
    Filed: December 21, 1987
    Date of Patent: July 18, 1989
    Assignee: Texas Instruments Incorporated
    Inventors: David B. Spratt, Eldon J. Zorinsky, Robert L. Virkus, Kenneth E. Bean, Richard L. Yeakley