Patents by Inventor Eugene A. Fitzgerald

Eugene A. Fitzgerald 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: 7495266
    Abstract: A semiconductor-based structure includes first and second layers bonded directly to each other at an interface. Parallel to the interface, the lattice spacing of the second layer is different than the lattice spacing of the first layer. The first and second layers are each formed of essentially the same semiconductor. A method for making a semiconductor-based structure includes providing first and second layers that are formed of essentially the same semiconductor. The first and second layers have, respectively, first and second surfaces. The second layer has a different lattice spacing parallel to the second surface than the lattice spacing of the first layer parallel to the first surface. The method includes contacting the first and second surfaces, and annealing to promote direct atomic bonding between the first and second layers.
    Type: Grant
    Filed: June 16, 2004
    Date of Patent: February 24, 2009
    Assignee: Massachusetts Institute of Technology
    Inventors: David M. Isaacson, Eugene A. Fitzgerald
  • Patent number: 7465619
    Abstract: A semiconductor-based device includes a channel layer, which includes a distal layer and a proximal layer in contact with the distal layer. The distal layer supports at least a portion of hole conduction for at least one p-channel component, and the proximal layer supports at least a portion of electron conduction for at least one n-channel component. The proximal layer has a thickness that permits a hole wave function to effectively extend from the proximal layer into the distal layer to facilitate hole conduction by the distal layer. A method for fabricating a semiconductor-based device includes providing a distal portion of a channel layer and providing a proximal portion of the channel layer.
    Type: Grant
    Filed: May 17, 2005
    Date of Patent: December 16, 2008
    Assignee: Amberwave Systems Corporation
    Inventor: Eugene A. Fitzgerald
  • Patent number: 7420201
    Abstract: The benefits of strained semiconductors are combined with silicon-on-insulator approaches to substrate and device fabrication.
    Type: Grant
    Filed: May 10, 2005
    Date of Patent: September 2, 2008
    Assignee: AmberWave Systems Corporation
    Inventors: Thomas A. Langdo, Matthew T. Currie, Richard Hammond, Anthony J. Lochtefeld, Eugene A. Fitzgerald
  • Patent number: 7414259
    Abstract: The benefits of strained semiconductors are combined with silicon-on-insulator approaches to substrate and device fabrication.
    Type: Grant
    Filed: May 11, 2005
    Date of Patent: August 19, 2008
    Assignee: AmberWave Systems Corporation
    Inventors: Thomas A. Langdo, Matthew T. Currie, Richard Hammond, Anthony J. Lochtefeld, Eugene A. Fitzgerald
  • Publication number: 20080149915
    Abstract: Semiconductor light-emitting structures are shown on engineered substrates having a graded composition. The composition of the substrate may be graded to achieve a lattice constant on which a yellow-green light-emitting semiconductor material may be disposed. In some embodiments, the structure may be substantially free of aluminum.
    Type: Application
    Filed: June 28, 2007
    Publication date: June 26, 2008
    Applicant: Massachusetts Institute of Technology
    Inventors: Michael J. Mori, Eugene A. Fitzgerald
  • Patent number: 7390701
    Abstract: A multiple-gate FET structure includes a semiconductor substrate. A gate region is formed on the semiconductor substrate. The gate region comprises a gate portion and a channel portion. The gate portion has at least two opposite vertical surfaces adjacent to the channel portion. A source region abuts the gate region at one end, and a drain diffusion region abuts the gate region at the other end.
    Type: Grant
    Filed: March 23, 2005
    Date of Patent: June 24, 2008
    Assignee: Massachusetts Institute of Technology
    Inventors: Zhiyuan Cheng, Eugene A. Fitzgerald, Dimitri Antoniadis
  • Publication number: 20080128751
    Abstract: The benefits of strained semiconductors are combined with silicon-on-insulator approaches to substrate and device fabrication.
    Type: Application
    Filed: November 20, 2007
    Publication date: June 5, 2008
    Applicant: AmberWave Systems Corporation
    Inventors: Thomas A. Langdo, Matthew T. Currie, Richard Hammond, Anthony J. Lochtefeld, Eugene A. Fitzgerald
  • Publication number: 20080128747
    Abstract: The invention provides semiconductor structure comprising a strained Ge channel layer, and a gate dielectric disposed over the strained Ge channel layer. In one aspect of the invention, a strained Ge channel MOSFET is provided. The strained Ge channel MOSFET includes a relaxed SiGe virtual substrate with a Ge content between 50-95%, and a strained Ge channel formed on the virtual substrate. A gate structure is formed upon the strained Ge channel, whereupon a MOSFET is formed with increased performance over bulk Si. In another embodiment of the invention, a semiconductor structure comprising a relaxed Ge channel layer and a virtual substrate, wherein the relaxed Ge channel layer is disposed above the virtual substrate. In a further aspect of the invention, a relaxed Ge channel MOSFET is provided. The method includes providing a relaxed virtual substrate with a Ge composition of approximately 100% and a relaxed Ge channel formed on the virtual substrate.
    Type: Application
    Filed: October 23, 2007
    Publication date: June 5, 2008
    Inventors: Minjoo L. Lee, Christopher W. Leitz, Eugene A. Fitzgerald
  • Patent number: 7348259
    Abstract: A method of fabricating a semiconductor structure. According to one aspect of the invention, on a first semiconductor substrate, a first compositionally graded Si1-xGex buffer is deposited where the Ge composition x is increasing from about zero to a value less than about 20%. Then a first etch-stop Si1-yGey layer is deposited where the Ge composition y is larger than about 20% so that the layer is an effective etch-stop. A second etch-stop layer of strained Si is then grown. The deposited layer is bonded to a second substrate. After that the first substrate is removed to release said first etch-stop S1-yGey layer. The remaining structure is then removed in another step to release the second etch-stop layer. According to another aspect of the invention, a semiconductor structure is provided. The structure has a layer in which semiconductor devices are to be formed.
    Type: Grant
    Filed: January 3, 2005
    Date of Patent: March 25, 2008
    Assignee: Massachusetts Institute of Technology
    Inventors: Zhiyuan Cheng, Eugene A. Fitzgerald, Dimitri A. Antoniadis
  • Publication number: 20070293009
    Abstract: Semiconductor structures and devices including strained material layers having impurity-free zones, and methods for fabricating same. Certain regions of the strained material layers are kept free of impurities that can interdiffuse from adjacent portions of the semiconductor. When impurities are present in certain regions of the strained material layers, there is degradation in device performance. By employing semiconductor structures and devices (e.g., field effect transistors or “FETs”) that have the features described, or are fabricated in accordance with the steps described, device operation is enhanced.
    Type: Application
    Filed: August 31, 2007
    Publication date: December 20, 2007
    Inventors: Matthew Currie, Anthony Lochtefeld, Richard Hammond, Eugene Fitzgerald
  • Publication number: 20070293003
    Abstract: Semiconductor structures and devices including strained material layers having impurity-free zones, and methods for fabricating same. Certain regions of the strained material layers are kept free of impurities that can interdiffuse from adjacent portions of the semiconductor. When impurities are present in certain regions of the strained material layers, there is degradation in device performance. By employing semiconductor structures and devices (e.g., field effect transistors or “FETs”) that have the features described, or are fabricated in accordance with the steps described, device operation is enhanced.
    Type: Application
    Filed: August 30, 2007
    Publication date: December 20, 2007
    Inventors: Matthew Currie, Anthony Lochtefeld, Richard Hammond, Eugene Fitzgerald
  • Patent number: 7304336
    Abstract: A multiple-gate FET structure includes a semiconductor substrate. A gate region is formed on the semiconductor substrate. The gate region comprises a gate portion and a channel portion. The gate portion has at least two opposite vertical surfaces adjacent to the channel portion. A source region abuts the gate region at one end, and a drain diffusion region abuts the gate region at the other end.
    Type: Grant
    Filed: February 13, 2004
    Date of Patent: December 4, 2007
    Assignee: Massachusetts Institute of Technology
    Inventors: Zhiyuan Cheng, Eugene A. Fitzgerald, Dimitri Antoniadis
  • Patent number: 7301180
    Abstract: The invention provides semiconductor structure comprising a strained Ge channel layer, and a gate dielectric disposed over the strained Ge channel layer. In one aspect of the invention, a strained Ge channel MOSFET is provided. The strained Ge channel MOSFET includes a relaxed SiGe virtual substrate with a Ge content between 50-95%, and a strained Ge channel formed on the virtual substrate. A gate structure is formed upon the strained Ge channel, whereupon a MOSFET is formed with increased performance over bulk Si. In another embodiment of the invention, a semiconductor structure comprising a relaxed Ge channel layer and a virtual substrate, wherein the relaxed Ge channel layer is disposed above the virtual substrate. In a further aspect of the invention, a relaxed Ge channel MOSFET is provided. The method includes providing a relaxed virtual substrate with a Ge composition of approximately 100% and a relaxed Ge channel formed on the virtual substrate.
    Type: Grant
    Filed: June 18, 2002
    Date of Patent: November 27, 2007
    Assignee: Massachusetts Institute of Technology
    Inventors: Minjoo L. Lee, Christopher W. Leitz, Eugene A. Fitzgerald
  • Patent number: 7297612
    Abstract: The benefits of strained semiconductors are combined with silicon-on-insulator approaches to substrate and device fabrication.
    Type: Grant
    Filed: May 12, 2005
    Date of Patent: November 20, 2007
    Assignee: AmberWave Systems Corporation
    Inventors: Thomas A. Langdo, Matthew T. Currie, Richard Hammond, Anthony J. Lochtefeld, Eugene A. Fitzgerald
  • Publication number: 20070252223
    Abstract: Structures and devices, and methods of making such structures and devices, including a gate dielectric layer are provided. A semiconductor structure can include a semiconductor channel layer including a nitride-free semiconductor layer and a gate dielectric layer including a group III-nitride layer, wherein the gate dielectric layer is disposed over the semiconductor channel layer. A method of making a semiconductor device structure is also provided. The method includes providing a semiconductor channel layer including a nitride-free semiconductor layer and providing a gate dielectric layer including a group III-nitride layer, wherein the gate dielectric layer is disposed over the semiconductor channel layer.
    Type: Application
    Filed: December 5, 2006
    Publication date: November 1, 2007
    Applicant: Massachusetts Institute of Technology
    Inventors: Minjoo Lee, Eugene Fitzgerald
  • Patent number: 7259388
    Abstract: The benefits of strained semiconductors are combined with silicon-on-insulator approaches to substrate and device fabrication.
    Type: Grant
    Filed: May 3, 2005
    Date of Patent: August 21, 2007
    Assignee: AmberWave Systems Corporation
    Inventors: Thomas A. Langdo, Matthew T. Currie, Richard Hammond, Anthony J. Lochtefeld, Eugene A. Fitzgerald
  • Patent number: 7259108
    Abstract: Methods for fabricating multi-layer semiconductor structures including strained material layers using a minimum number of process tools and under conditions optimized for each layer. Certain regions of the strained material layers are kept free of impurities that can interdiffuse from adjacent portions of the semiconductor. When impurities are present in certain regions of the strained material layers, there is degradation in device performance. By employing semiconductor structures and devices (e.g., field effect transistors or “FETs”) that have the features described, or are fabricated in accordance with the steps described, device operation is enhanced.
    Type: Grant
    Filed: February 27, 2006
    Date of Patent: August 21, 2007
    Assignee: AmberWave Systems Corporation
    Inventors: Eugene Fitzgerald, Matthew Currie
  • Patent number: 7256142
    Abstract: Structures and methods for fabricating high speed digital, analog, and combined digital/analog systems using planarized relaxed SiGe as the materials platform. The relaxed SiGe allows for a plethora of strained Si layers that possess enhanced electronic properties. By allowing the MOSFET channel to be either at the surface or buried, one can create high-speed digital and/or analog circuits. The planarization before the device epitaxial layers are deposited ensures a flat surface for state-of-the-art lithography.
    Type: Grant
    Filed: October 19, 2004
    Date of Patent: August 14, 2007
    Assignee: AmberWave Systems Corporation
    Inventor: Eugene A. Fitzgerald
  • Patent number: 7250359
    Abstract: A semiconductor structure including a semiconductor substrate, at least one first crystalline epitaxial layer on the substrate, the first layer having a surface which is planarized, and at least one second crystalline epitaxial layer on the at least one first layer. In another embodiment of the invention there is provided a semiconductor structure including a silicon substrate, and a GeSi graded region grown on the silicon substrate, compressive strain being incorporated in the graded region to offset the tensile strain that is incorporated during thermal processing. In yet another embodiment of the invention there is provided a semiconductor structure including a semiconductor substrate, a first layer having a graded region grown on the substrate, compressive strain being incorporated in the graded region to offset the tensile strain that is incorporated during thermal processing, the first layer having a surface which is planarized, and a second layer provided on the first layer.
    Type: Grant
    Filed: December 17, 2001
    Date of Patent: July 31, 2007
    Assignee: Massachusetts Institute of Technology
    Inventor: Eugene A. Fitzgerald
  • Patent number: 7227176
    Abstract: A semiconductor structure including a uniform etch-stop layer. The uniform etch stop layer has a relative etch rate which is less than approximately the relative etch rate of Si doped with 7×1019 boron atoms/cm3. A method for forming a semiconductor structure includes forming a uniform etch-stop layer providing a handle wafer, and bonding the uniform etch-stop layer to the handle wafer. The uniform etch-stop layer has a relative etch rate which is less than approximately the relative etch rate of Si doped with 7×1019 boron atoms/cm3.
    Type: Grant
    Filed: June 25, 2003
    Date of Patent: June 5, 2007
    Assignees: Massachusetts Institute of Technology, The Charles Stark Draper Laboratory, Inc.
    Inventors: Kenneth C. Wu, Eugene A. Fitzgerald, Gianni Taraschi, Jeffrey T. Borenstein