Patents by Inventor Brad W. Scharf

Brad W. Scharf 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: 6005282
    Abstract: Process for making an integrated-circuit (IC) chip with junction-isolated complementary bipolar transistors. In this process an N-well is formed in a P-type substrate. P-type dopant is implanted in the N-well to become a sub-collector for a pnp transistor. N-type dopant is implanted in the substrate in a location laterally displaced from the N-well to become a sub-collector for an npn transistor. N-type material is implanted in the N-well to begin the formation of an isolation wall for the pnp transistor. A P-type epitaxial (epi) layer then is grown over the P-type substrate. N-type material is implanted in the epi layer to complete the isolation wall for the pnp transistor, and to complete the collector for the npn transistor. P-type and N-type material also is implanted in the P-type epi layer to form the bases and emitters for the npn and pnp transistors.
    Type: Grant
    Filed: January 18, 1995
    Date of Patent: December 21, 1999
    Assignee: Analog Devices, Inc.
    Inventors: Jerome F. Lapham, Brad W. Scharf
  • Patent number: 5866462
    Abstract: Emitter widths of 0.3 .mu.m on double polysilicon bipolar transistors are achieved using O.8 .mu.m photolithography and a double spacer process. The emitter width reduction is confirmed with structural and electrical measurements. The double-spacer device exhibits superior low current f.sub.T and f.sub.max.
    Type: Grant
    Filed: September 29, 1995
    Date of Patent: February 2, 1999
    Assignee: Analog Devices, Incorporated
    Inventors: Curtis Tsai, Kenneth K. O, Brad W. Scharf
  • Patent number: 5759902
    Abstract: Process for making an integrated-circuit (IC) chip with junction-isolated complementary bipolar transistors, and novel chip made by such process. P-type dopant is implanted and diffused in an N-type substrate to form a sub-collector for a pnp transistor and also is implanted and diffused in the substrate to form a P-well for the sub-collector of an npn transistor. N-type material is then implanted and diffused into the P-well to form the npn sub-collector, and also is implanted in the substrate to form part of an isolation wall for the pnp transistor. A P-type epitaxial (epi) layer is grown over the N-type substrate. N-type material is implanted and diffused in the epi layer to complete the isolation wall for the pnp transistor, and to form the collector for the npn transistor. P-type and N-type material is implanted and diffused in the P-type epi layer to form the bases and emitters for the npn and pnp transistors.
    Type: Grant
    Filed: March 18, 1996
    Date of Patent: June 2, 1998
    Assignee: Analog Devices, Incorporated
    Inventors: Jerome F. Lapham, Brad W. Scharf
  • Patent number: 5529939
    Abstract: Process for making an integrated-circuit (IC) chip with junction-isolated complementary bipolar transistors. In this process an N-well is formed in a P-type substrate. P-type dopant is implanted in the N-well to become a sub-collector for a pnp transistor. N-type dopant is implanted in the substrate in a location laterally displaced from the N-well to become a sub-collector for an npn transistor. N-type material is implanted in the N-well to begin the formation of an isolation wall for the pnp transistor. A P-type epitaxial (epi) layer then is grown over the P-type substrate. N-type material is implanted in the epi layer to complete the isolation wall for the pnp transistor, and to complete the collector for the npn transistor. P-type and N-type material also is implanted in the P-type epi layer to form the bases and emitters for the npn and pnp transistors.
    Type: Grant
    Filed: November 4, 1994
    Date of Patent: June 25, 1996
    Assignee: Analog Devices, Incorporated
    Inventors: Jerome F. Lapham, Brad W. Scharf
  • Patent number: 5422510
    Abstract: An MOS transistor wherein the channel between the source and drain is formed with two regions having different dopant concentrations. The region adjacent the source has a normal concentration, while that adjacent the drain has a reduced dopant concentration. This reduces the degrading effects of hot carrier injection, thereby extending the life of the transistor.
    Type: Grant
    Filed: October 30, 1992
    Date of Patent: June 6, 1995
    Assignee: Analog Devices, Incorporated
    Inventors: Brad W. Scharf, Faran Nouri, Shaheen Mohamedi
  • Patent number: 5302848
    Abstract: A process for making an integrated-circuit (IC) chip with junction-isolated complementary bipolar transistors, and a novel chip made by such a process. P-type dopant is implanted and diffused in an N-type substrate to form a sub-collector for a pnp transistor and also is implanted and diffused in the substrate to form a P-well for the sub-collector of an npn transistor. N-type material is then implanted and diffused into the P-well to form the npn sub-collector, and also is implanted in the substrate to form part of an isolation wall for the pnp transistor. A P-type epitaxial (epi) layer is grown over the N-type substrate. N-type material is implanted and diffused in the epi layer to complete the isolation wall for the pnp transistor, and to form the collector for the npn transistor. P-type and N-type material is implanted and diffused in the P-type epi layer to form the bases and emitters for the npn and pnp transistors.
    Type: Grant
    Filed: March 1, 1993
    Date of Patent: April 12, 1994
    Assignee: Analog Devices, Inc.
    Inventors: Jerome F. Lapham, Brad W. Scharf
  • Patent number: 5065214
    Abstract: An integrated-circuit (IC) chip with junction-isolated complementary bipolar transistors, is disclosed. P-type dopant is implanted and diffused in an N-type substrate to form a sub-collector for a pnp transistor and also is implanted and diffused in the substrate to form a P-well for the sub-collector of an npn transistor. N-type material is then implanted and diffused into the P-well to form the npn sub-collector, and also is implanted in the substrate to form part of an isolation wall for the pnp transistor. A P-type epitaxial (epi) layer is grown over the N-type substrate. N-type material is implanted and diffused in the epi layer to complete the isolation wall for the pnp transistor, and to form the collector for the npn transistor. P-type and N-type material is implanted and diffused in the P-type epi layer to form the bases and emitters for the npn and pnp transistors.
    Type: Grant
    Filed: November 1, 1989
    Date of Patent: November 12, 1991
    Assignee: Analog Devices, Incorporated
    Inventors: Jerome F. Lapham, Brad W. Scharf
  • Patent number: 4969823
    Abstract: Process for making an integrated-circuit (IC) chip with junction-isolated complementary bipolar transistors, and novel chip made by such process. P-type dopant is implanted and diffused in an N-type substrate to form a sub-collector for a pnp transistor and also is implanted and diffused in the substrate to form a P-well for the sub-collector of an npn transistor. N-type material is then implanted and diffused into the P-well to form the npn sub-collector, and also is implanted in the substrate to form part of an isolation wall for the pnp transistor. A P-type epitaxial (epi) layer is grown over the N-type substrate. N-type material is implanted and diffused in the epi layer to complete the isolation wall for the pnp transistor, and to form the collector for the npn transistor. P-type and N-type material is implanted and diffused in the P-type epi layer to form the bases and emitters for the npn and pnp transistors.
    Type: Grant
    Filed: May 5, 1988
    Date of Patent: November 13, 1990
    Assignee: Analog Devices, Incorporated
    Inventors: Jerome F. Lapham, Brad W. Scharf