Patents Assigned to COVA Technologies, Inc.
  • Patent number: 7034349
    Abstract: A method of storing and accessing two data bits in a single ferroelectric FET includes selectively polarizing two distinct ferroelectric regions in the same gate dielectric layer separated by a non-ferroelectric dielectric region. A first ferroelectric region is sandwiched between the substrate and the gate terminal in the region of the source and is polarized in one of two states to form a first data bit within the FET. A second ferroelectric region is sandwiched between the substrate and the gate terminal in the region of the drain and is polarized in one of two states to form a second data bit within the FET. Detection of the first data bit is accomplished by selectively applying a read bias to the FET terminals, a first current resulting when a first state is stored and a second current resulting when a second state is stored. The polarization of the second data bit is accomplished by reversing the source and drain voltages.
    Type: Grant
    Filed: January 6, 2004
    Date of Patent: April 25, 2006
    Assignee: Cova Technologies, Inc.
    Inventors: Klaus Dimmler, Alfred P. Gnadinger
  • Patent number: 7030435
    Abstract: A memory device is formed of the one transistor cell type. Such a device has a substrate, a ferroelectric layer which is a film of rare earth manganite, and an interfacial oxide layer being positioned between the substrate and the ferroelectric layer. The invention includes such a device and methods of making the same.
    Type: Grant
    Filed: August 24, 2001
    Date of Patent: April 18, 2006
    Assignee: COVA Technologies, Inc.
    Inventor: Fred P. Gnadinger
  • Patent number: 6908772
    Abstract: A single transistor (“1T”) ferroelectric memory cell, device and method for the formation of the same incorporating a high temperature ferroelectric gate dielectric. The memory cell of the present invention comprises a substrate, an overlying ferroelectric layer, which may comprise a film of rare earth manganite, and an interfacial oxide layer intermediate the substrate and the ferroelectric layer. In a preferred embodiment, the ferroelectric material utilized in an implementation of the present invention may be deposited by metallorganic chemical vapor deposition (“MOCVD”) or other techniques and exhibits a low relative dielectric permittivity of around 10 and forms an interfacial layer with a relative dielectric permittivity larger than that of SiO2, which makes it particularly suitable for a 1T cell.
    Type: Grant
    Filed: June 4, 2003
    Date of Patent: June 21, 2005
    Assignee: COVA Technologies, Inc.
    Inventor: Alfred P. Gnadinger
  • Patent number: 6888736
    Abstract: A method of storing and accessing two data bits in a single ferroelectric FET includes selectively polarizing two distinct ferroelectric regions in the same gate dielectric layer separated by a non-ferroelectric dielectric region. A first ferroelectric region is sandwiched between the substrate and the gate terminal in the region of the source and is polarized in one of two states to form a first data bit within the FET. A second ferroelectric region is sandwiched between the substrate and the gate terminal in the region of the drain and is polarized in one of two states to form a second data bit within the FET. Detection of the first data bit is accomplished by selectively applying a read bias to the FET terminals, a first current resulting when a first state is stored and a second current resulting when a second state is stored. The polarization of the second data bit is accomplished by reversing the source and drain voltages.
    Type: Grant
    Filed: November 26, 2002
    Date of Patent: May 3, 2005
    Assignee: COVA Technologies, Inc.
    Inventors: Klaus Dimmler, Alfred P. Gnadinger
  • Patent number: 6825517
    Abstract: Data retention of a ferroelectric transistor is extended by intecting holes or electrons into the ferroelectric transistor when power is removed. The ferroelectric FET has a mechanism to trap charge in a buffer dielectric layer or in the ferroelectric layer sandwiched between a top electrode and a silicon substrate. The state of polarization is detected before power is removed from the ferroelectric FET. Charge is injected into the ferroelectric FET to produce a first threshold voltage when a first polarization state is determined before power is removed. Charge is removed from the ferroelectric FET to produce a second threshold voltage when a second polarization state is determined before power is removed. When the ferroelectric FET is powered up again, the state of charge injected is determined. The ferroelectric FET is then polarized to correspond to a first threshold voltage when the charge state corresponding to the first threshold is determined.
    Type: Grant
    Filed: August 28, 2002
    Date of Patent: November 30, 2004
    Assignee: COVA Technologies, Inc.
    Inventors: Klaus Dimmler, Alfred P. Gnadinger
  • Patent number: 6790679
    Abstract: Data retention of a ferroelectric transistor is extended by injecting holes or electrons into the ferroelectric transistor when power is removed. The ferroelectric FET has a mechanism to trap charge in a buffer dielectric layer or in the ferroelectric layer sandwiched between a top electrode and a silicon substrate. The state of polarization is detected before power is removed from the ferroelectric FET. Charge is injected into the ferroelectric FET to produce a first threshold voltage when a first polarization state is determined before power is removed. Charge is removed from the ferroelectric FET to produce a second threshold voltage when a second polarization state is determined before power is removed. When the ferroelectric FET is powered up again, the state of charge injected is determined. The ferroelectric FET is then polarized to correspond to a first threshold voltage when the charge state corresponding to the first threshold is determined.
    Type: Grant
    Filed: July 16, 2003
    Date of Patent: September 14, 2004
    Assignee: Cova Technologies, Inc.
    Inventors: Klaus Dimmler, Alfred P. Gnadinger
  • Patent number: 6714435
    Abstract: A method of storing and accessing two data bits in a single ferroelectric FET includes selectively polarizing two distinct ferroelectric regions in the same gate dielectric layer separated by a non-ferroelectric dielectric region. A first ferroelectric region is sandwiched between the substrate and the gate terminal in the region of the source and is polarized in one of two states to form a first data bit within the FET. A second ferroelectric region is sandwiched between the substrate and the gate terminal in the region of the drain and is polarized in one of two states to form a second data bit within the FET. Detection of the first data bit is accomplished by selectively applying a read bias to the FET terminals, a first current resulting when a first state is stored and a second current resulting when a second state is stored. The polarization of the second data bit is accomplished by reversing the source and drain voltages.
    Type: Grant
    Filed: September 19, 2002
    Date of Patent: March 30, 2004
    Assignee: Cova Technologies, Inc.
    Inventors: Klaus Dimmler, Alfred P. Gnadinger
  • Publication number: 20040057319
    Abstract: A method of storing and accessing two data bits in a single ferroelectric FET includes selectively polarizing two distinct ferroelectric regions in the same gate dielectric layer separated by a non-ferroelectric dielectric region. A first ferroelectric region is sandwiched between the substrate and the gate terminal in the region of the source and is polarized in one of two states to form a first data bit within the FET. A second ferroelectric region is sandwiched between the substrate and the gate terminal in the region of the drain and is polarized in one of two states to form a second data bit within the FET. Detection of the first data bit is accomplished by selectively applying a read bias to the FET terminals, a first current resulting when a first state is stored and a second current resulting when a second state is stored. The polarization of the second data bit is accomplished by reversing the source and drain voltages.
    Type: Application
    Filed: November 26, 2002
    Publication date: March 25, 2004
    Applicant: COVA Technologies, Inc.
    Inventors: Klaus Dimmler, Alfred P. Gnadinger
  • Patent number: 6674110
    Abstract: A single transistor (“1T”) ferroelectric memory cell, device and method for the formation of the same incorporating a high temperature ferroelectric gate dielectric. The memory cell of the present invention comprises a substrate, an overlying ferroelectric layer, which may comprise a film of rare earth manganite, and an interfacial oxide layer intermediate the substrate and the ferroelectric layer. In a preferred embodiment, the ferroelectric material utilized in an implementation of the present invention may be deposited by metallorganic chemical vapor deposition (“MOCVD”) or other techniques and exhibits a low relative dielectric permittivity of around 10 and forms an interfacial layer with a relative dielectric permittivity larger than that of SiO2, which makes it particularly suitable for a 1T cell.
    Type: Grant
    Filed: March 1, 2002
    Date of Patent: January 6, 2004
    Assignee: COVA Technologies, Inc.
    Inventor: Alfred P. Gnadinger