Patents by Inventor Kevin R. Hoffman

Kevin R. Hoffman 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: 4574733
    Abstract: Apparatus for shielding substrates from plasma developed adjacent the ends of r.f. powered cathodes, the apparatus adapted for use in a glow discharge deposition system in which successive amorphous semiconductor layers are deposited onto a substrate. The deposition system includes at least one deposition chamber into which process gases are introduced and disassociated in the presence of electrodynamic fields created between a cathode and a substrate. The shielding apparatus of the present invention comprises a pair of relatively narrow, elongated plates adapted to be spacedly disposed in the deposition chamber so as to lie in a plane substantially parallel to the plane of the substrate. By disposing one of the plates adjacent each of the ends of the cathode, only homogeneous semiconductor films formed by uniform electrodynamic fields produced adjacent the central portion of the cathode are deposited onto the substrate.
    Type: Grant
    Filed: September 16, 1982
    Date of Patent: March 11, 1986
    Assignee: Energy Conversion Devices, Inc.
    Inventors: Prem Nath, Kevin R. Hoffman
  • Patent number: 4537795
    Abstract: A method for introducing sweep gas through a baffle system adapted for use with glow discharge deposition apparatus in which successive amorphous semiconductor layers are deposited on a substrate. The deposition apparatus includes at least a pair of adjacent dedicated deposition chambers into each of which different process gases are introduced, the chambers being operatively connected by a gas gate. Inert gases are swept through the gas gate to minimize back diffusion of process gases from the chambers. The baffle system is adapted to prevent said sweep gases from entering into turbulent flow when traveling through the gas gate passageway. Further, a sufficient volume per unit time of sweep gas is introduced to insure that some sweep gas flows into the cathode region of the first chamber, thereby substantially preventing process gases and plasma from escaping from the cathode region and forming silane powder.
    Type: Grant
    Filed: August 3, 1984
    Date of Patent: August 27, 1985
    Assignee: Sovonics Solar Systems
    Inventors: Prem Nath, Kevin R. Hoffman, Timothy D. Laarman
  • Patent number: 4520757
    Abstract: A system for introducing, confining and evacuating process gases adjacent the cathode region of glow discharge deposition apparatus, said apparatus adapted to deposit at least one layer of semiconductor material onto a substrate. The deposition apparatus includes at least one dedicated deposition chamber into which process gases are introduced for glow discharge disassociation into species. The system of the present invention includes a baffling manifold adjacent the cathode, said manifold adapted to (1) substantially prevent adjacent slowly and rapidly moving streams of process gases from forming flow patterns as the semiconductor material is deposited onto the substrate, and (2) thoroughly mix the process gases for only introducing homogeneous, uniform process gas mixtures into the plasma region, thereby preventing adjacent nonhomogeneous, nonuniform mixtures from forming flow patterns as the semiconductor material is deposited onto the substrate.
    Type: Grant
    Filed: December 23, 1983
    Date of Patent: June 4, 1985
    Assignee: Energy Conversion Devices, Inc.
    Inventors: Prem Nath, Kevin R. Hoffman, Timothy D. Laarman
  • Patent number: 4479455
    Abstract: A process gas introduction and channeling system for use with apparatus adapted to produce photovoltaic devices by depositing semiconductor layers onto continuously moving substrate material. The deposition apparatus preferably includes at least one deposition chamber having (1) a region in which process gases are decomposed and (2) a manifold from which process gases are introduced to flow through the downstream decomposition region. In the preferred embodiment, as the process gases flow through the decomposition region, they are disassociated and recombined under the influence of an electromagnetic field. The species and combinations of process gases thus formed are deposited onto the substrate material.
    Type: Grant
    Filed: March 14, 1983
    Date of Patent: October 30, 1984
    Assignee: Energy Conversion Devices, Inc.
    Inventors: Joachim Doehler, Kevin R. Hoffman, Timothy D. Laarman, Gary M. DiDio, Therese McDonough
  • Patent number: 4462333
    Abstract: A system for introducing, confining and evacuating process gases adjacent the cathode region of glow discharge deposition apparatus, said apparatus adapted to deposit at least one layer of semiconductor material onto a substrate. The deposition apparatus includes at least one dedicated deposition chamber into which process gases are introduced for glow discharge disassociation into species. The system of the present invention includes a baffling manifold adjacent the cathode, said manifold adapted to substantially reduce areas of localized rarification and compression of process gases flowing through the plasma region for substantially preventing adjacent stagnant and rapidly moving areas of process gases from forming nonuniform flow patterns as the semiconductor layer is deposited on the surface of the substrate. The system is also adapted to expose the entire transverse width of the substrate for the deposition of semiconductor material thereunto.
    Type: Grant
    Filed: October 27, 1982
    Date of Patent: July 31, 1984
    Assignee: Energy Conversion Devices, Inc.
    Inventors: Prem Nath, Kevin R. Hoffman, Timothy D. Laarman
  • Patent number: 4450786
    Abstract: An improved magnetic gas gate is adapted to operatively interconnect two adjacent chambers, in the first chamber of which process gases are introduced for depositing a first layer upon a magnetic substrate and in the second chamber of which process gases are introduced for depositing a second layer atop the first layer. Since it is important to prevent the second chamber gases from contaminating the first chamber gases, a constant pressure differential established between the chambers is employed to provide a substantially unidirectional flow of gases from the first chamber into the second chamber. Magnetic gas gates have been used in the prior art to reduce the size of gas gate passageways by creating a magnetic field which urges the unlayered surface of the substrate toward a wall of the passageway.
    Type: Grant
    Filed: February 16, 1983
    Date of Patent: May 29, 1984
    Assignee: Energy Conversion Devices, Inc.
    Inventors: Joachim Doehler, David A. Gattuso, Kevin R. Hoffman
  • Patent number: 4438724
    Abstract: A grooved passageway surface in a magnetic gas gate, the gas gate adapted to operatively connect two adjacent chambers, in the first chamber of which process gases are introduced for depositing a first layer upon a magnetic substrate and in the second chamber of which process gases are introduced for depositing a second layer atop the first layer. Since it is important to prevent the second chamber gases from contaminating the first chamber gases, a constant pressure differential established between the chambers is employed to provide a substantially unidirectional flow of gases from the first chamber into the second chamber. Magnetic gas gates have been used in the prior art to reduce the size of gas gate passageways by creating a magnetic field which urges the unlayered surface of the substrate toward a wall of the passageway.
    Type: Grant
    Filed: August 13, 1982
    Date of Patent: March 27, 1984
    Assignee: Energy Conversion Devices, Inc.
    Inventors: Joachim Doehler, David A. Gattuso, Kevin R. Hoffman