Patents by Inventor Michael Rowlandson

Michael Rowlandson 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: 7026666
    Abstract: A self-aligned bipolar transistor and a method of formation thereof are provided. The bipolar transistor has a raised extrinsic base such that the link base resistance is reduced by providing an extrinsic base which is thicker than the intrinsic base. The increase in thickness of the extrinsic base provides a less resistive layer of the heavily doped base region. The method of forming the bipolar transistor includes depositing a first epitaxial layer on a substrate to form a base region having an intrinsic base region and an extrinsic base region. The extrinsic base region is raised by depositing a second epitaxial layer over a portion of the first epitaxial layer such that the thickness of the extrinsic base layer is x and the thickness of the intrinsic layer is y, wherein x>y. The second epitaxial layer is deposited using a chemical vapor epitaxial device where the concentration of Ge to Si is gradually reduced from above 5% to close to 0% during the epitaxy process.
    Type: Grant
    Filed: December 12, 2003
    Date of Patent: April 11, 2006
    Assignee: Maxim Integrated Products, Inc.
    Inventors: Alexander Kalnitsky, Alexel Shatalov, Michael Rowlandson, Sang H. Park, Robert F. Scheer, Fanling H. Yang
  • Patent number: 6861324
    Abstract: The present invention provides a method of forming a super self-aligned bipolar transistor with enhanced electrical characteristics. The power gain and frequency response of the transistor are improved by horizontally etching an area for the base region that is wider than the active emitter and collector regions. By removing polysilicon layers within the device, the base region resistance goes down and unwanted capacitive effects are reduced.
    Type: Grant
    Filed: June 15, 2001
    Date of Patent: March 1, 2005
    Assignee: Maxim Integrated Products, Inc.
    Inventors: Alexander Kalnitsky, Michael Rowlandson, Ken Liao, Robert F. Scheer
  • Patent number: 6845044
    Abstract: A CMOS memory cell (FIG. 1) is provided which includes a PMOS transistor (102) and an NMOS transistor (104) with a common floating gate and common drains configured to prevent a large drain of Icc current from a power supply during power-up. To prevent the large Icc during power-up, the threshold voltages of the PMOS transistor (102) and NMOS transistor (104) are set so that the PMOS transistor (102) and NMOS transistor (104) do not turn on together, irrespective of charge initially stored on the floating gate. Without such thresholds, a significant drain of current Icc from the power supply connection Vcc can occur since charge initially on the floating gate leaves both the PMOS transistor (102) and the NMOS transistor (104) on creating a path for Icc from Vcc to Vss.
    Type: Grant
    Filed: January 29, 2002
    Date of Patent: January 18, 2005
    Assignee: Lattice Semiconductor Corporation
    Inventors: Andrew Horch, Michael Rowlandson
  • Patent number: 6767798
    Abstract: A self-aligned bipolar transistor and a method of formation thereof are provided. The bipolar transistor has a raised extrinsic base such that the link base resistance is reduced by providing an extrinsic base which is thicker than the intrinsic base. The increase in thickness of the extrinsic base provides a less resistive layer of the heavily doped base region. The method of forming the bipolar transistor includes depositing a first epitaxial layer on a substrate to form a base region having an intrinsic base region and an extrinsic base region. The extrinsic base region is raised by depositing a second epitaxial layer over a portion of the first epitaxial layer such that the thickness of the extrinsic base layer is x and the thickness of the intrinsic layer is y, wherein x>y. The second epitaxial layer is deposited using a chemical vapor epitaxial device where the concentration of Ge to Si is gradually reduced from above 5% to close to 0% during the epitaxy process.
    Type: Grant
    Filed: April 9, 2002
    Date of Patent: July 27, 2004
    Assignee: Maxim Integrated Products, Inc.
    Inventors: Alexander Kalnitsky, Alexei Shatalov, Michael Rowlandson, Sang H. Park, Robert F. Scheer, Fanling H. Yang
  • Publication number: 20040126978
    Abstract: A self-aligned bipolar transistor and a method of formation thereof are provided. The bipolar transistor has a raised extrinsic base such that the link base resistance is reduced by providing an extrinsic base which is thicker than the intrinsic base. The increase in thickness of the extrinsic base provides a less resistive layer of the heavily doped base region. The method of forming the bipolar transistor includes depositing a first epitaxial layer on a substrate to form a base region having an intrinsic base region and an extrinsic base region. The extrinsic base region is raised by depositing a second epitaxial layer over a portion of the first epitaxial layer such that the thickness of the extrinsic base layer is x and the thickness of the intrinsic layer is y, wherein x>y. The second epitaxial layer is deposited using a chemical vapor epitaxial device where the concentration of Ge to Si is gradually reduced from above 5% to close to 0% during the epitaxy process.
    Type: Application
    Filed: December 12, 2003
    Publication date: July 1, 2004
    Inventors: Alexander Kalnitsky, Alexel Shatalov, Michael Rowlandson, Sang H. Park, Robert F. Scheer, Fanling H. Yang
  • Patent number: 6686250
    Abstract: A self-aligned bipolar transistor and a method of formation thereof are provided. The bipolar transistor has an emitter region characterized by a y-shaped structure formed from bilayer polysilicon. The bilayer polysilicon includes a first polysilicon emitter structure and a second polysilicon emitter structure. The method of forming the bipolar transistor includes forming an emitter stack on a substrate. The emitter stack comprises the first polysilicon emitter structure and a plug structure. The emitter stack defines the substrate into a masked portion and exposed adjacent portions. The exposed adjacent portions are selectively doped with a dopant to define an extrinsic base region, wherein the dopant is blocked from entering the masked portion. After selectively doping the extrinsic base region, the plug structure is removed from the emitter stack and the second polysilicon emitter structure is formed on the first polysilicon emitter structure to define the emitter region of the bipolar transistor.
    Type: Grant
    Filed: November 20, 2002
    Date of Patent: February 3, 2004
    Assignee: Maxim Integrated Products, Inc.
    Inventors: Alexander Kalnitsky, Michael Rowlandson, Fanling H. Yang, Sang Park, Robert F. Scheer
  • Patent number: 6636442
    Abstract: A non-volatile memory cell (FIG. 3) is provided which includes three transistors, a floating gate non-volatile storage transistor (303) and two cascode connected select transistors (301-302). The two cascoded select transistors (301-302) act together to block the programming voltage when the memory cell is included in an array, and the memory cell is not selected for programming. A value of an unselect voltage applied to the gate of the first cascode connected transistor (301) is set to prevent breakdown of the oxide in the first cascode transistor (301) as well as the second cascode transistor (302). A value of an unselect voltage applied to the gate of the second cascode connected transistor (302) can be selected so that the voltage passed to the floating gate storage transistor (303) will not result in a program drain disturb, or source disturb condition.
    Type: Grant
    Filed: January 29, 2002
    Date of Patent: October 21, 2003
    Assignee: Lattice Semiconductor Corporation
    Inventors: Michael Rowlandson, Andrew Horch
  • Publication number: 20030189239
    Abstract: A self-aligned bipolar transistor and a method of formation thereof are provided. The bipolar transistor has a raised extrinsic base such that the link base resistance is reduced by providing an extrinsic base which is thicker than the intrinsic base. The increase in thickness of the extrinsic base provides a less resistive layer of the heavily doped base region. The method of forming the bipolar transistor includes depositing a first epitaxial layer on a substrate to form a base region having an intrinsic base region and an extrinsic base region. The extrinsic base region is raised by depositing a second epitaxial layer over a portion of the first epitaxial layer such that the thickness of the extrinsic base layer is x and the thickness of the intrinsic layer is y, wherein x>y. The second epitaxial layer is deposited using a chemical vapor epitaxial device where the concentration of Ge to Si is gradually reduced from above 5% to close to 0% during the epitaxy process.
    Type: Application
    Filed: April 9, 2002
    Publication date: October 9, 2003
    Inventors: Alexander Kalnitsky, Alexei Shatalov, Michael Rowlandson, Sang H. Park, Robert F. Scheer, Fanling H. Yang
  • Publication number: 20030142549
    Abstract: A non-volatile memory cell (FIG. 3) is provided which includes three transistors, a floating gate non-volatile storage transistor (303) and two cascode connected select transistors (301-302). The two cascoded select transistors (301-302) act together to block the programming voltage when the memory cell is included in an array, and the memory cell is not selected for programming. A value of an unselect voltage applied to the gate of the first cascode connected transistor (301) is set to prevent breakdown of the oxide in the first cascode transistor (301) as well as the second cascode transistor (302). A value of an unselect voltage applied to the gate of the second cascode connected transistor (302) can be selected so that the voltage passed to the floating gate storage transistor (303) will not result in a program drain disturb, or source disturb condition.
    Type: Application
    Filed: January 29, 2002
    Publication date: July 31, 2003
    Inventors: Michael Rowlandson, Andrew Horch
  • Publication number: 20030143793
    Abstract: A CMOS memory cell (FIG. 1) is provided which includes a PMOS transistor (102) and an NMOS transistor (104) with a common floating gate and common drains configured to prevent a large drain of Icc current from a power supply during power-up. To prevent the large Icc during power-up, the threshold voltages of the PMOS transistor (102) and NMOS transistor (104) are set so that the PMOS transistor (102) and NMOS transistor (104) do not turn on together, irrespective of charge initially stored on the floating gate. Without such thresholds, a significant drain of current Icc from the power supply connection Vcc can occur since charge initially on the floating gate leaves both the PMOS transistor (102) and the NMOS transistor (104) on creating a path for Icc from Vcc to Vss.
    Type: Application
    Filed: January 29, 2002
    Publication date: July 31, 2003
    Inventors: Andrew Horch, Michael Rowlandson
  • Publication number: 20020192894
    Abstract: The present invention provides a method of forming a super self-aligned bipolar transistor with enhanced electrical characteristics. The power gain and frequency response of the transistor are improved by horizontally etching an area for the base region that is wider than the active emitter and collector regions. By removing polysilicon layers within the device, the base region resistance goes down and unwanted capacitive effects are reduced.
    Type: Application
    Filed: June 15, 2001
    Publication date: December 19, 2002
    Inventors: Alexander Kalnitsky, Michael Rowlandson, Ken Liao, Robert F. Scheer