Patents by Inventor Timothy J. Drummond

Timothy J. Drummond 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: 5825049
    Abstract: A double electron layer tunneling device is presented. Electrons tunnel from a two dimensional emitter layer to a two dimensional tunneling layer and continue traveling to a collector at a lower voltage. The emitter layer is interrupted by an isolation etch, a depletion gate, or an ion implant to prevent electrons from traveling from the source along the emitter to the drain. The collector is similarly interrupted by a backgate, an isolation etch, or an ion implant. When the device is used as a transistor, a control gate is added to control the allowed energy states of the emitter layer. The tunnel gate may be recessed to change the operating range of the device and allow for integrated complementary devices. Methods of forming the device are also set forth, utilizing epoxy-bond and stop etch (EBASE), pre-growth implantation of the backgate or post-growth implantation.
    Type: Grant
    Filed: October 9, 1996
    Date of Patent: October 20, 1998
    Assignee: Sandia Corporation
    Inventors: Jerry A. Simmons, Marc E. Sherwin, Timothy J. Drummond, Mark V. Weckwerth
  • Patent number: 5479033
    Abstract: A complimentary pair of compound semiconductor junction heterostructure field-effect transistors and a method for their manufacture are disclosed. The p-channel junction heterostructure field-effect transistor uses a strained layer to split the degeneracy of the valence band for a greatly improved hole mobility and speed. The n-channel device is formed by a compatible process after removing the strained layer. In this manner, both types of transistors may be independently optimized. Ion implantation is used to form the transistor active and isolation regions for both types of complimentary devices. The invention has uses for the development of low power, high-speed digital integrated circuits.
    Type: Grant
    Filed: May 27, 1994
    Date of Patent: December 26, 1995
    Assignee: Sandia Corporation
    Inventors: Albert G. Baca, Timothy J. Drummond, Perry J. Robertson, Thomas E. Zipperian
  • Patent number: 4947223
    Abstract: A semiconductor high reflector comprising a number of thin alternating layers of semiconductor materials is electrically tunable and may be used as a temperature insensitive semiconductor laser in a Fabry-Perot configuration.
    Type: Grant
    Filed: August 31, 1987
    Date of Patent: August 7, 1990
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventors: Robert M. Biefeld, Timothy J. Drummond, Paul L. Gourley, Thomas E. Zipperian
  • Patent number: 4829020
    Abstract: During the growth of compound semiconductors by epitaxial processes, substrates are typically mounted to a support. In modular beam epitaxy, mounting is done using indium as a solder. This method has two drawbacks: the indium reacts with the substrate, and it is difficult to uniformly wet the back of a large diameter substrate. Both of these problems have been successfully overcome by sputter coating the back of the substrate with a thin layer of tungsten carbide or tungsten carbide and gold. In addition to being compatible with the growth of high quality semiconductor epilayers this coating is also inert in all standard substrate cleaning etchants used for compound semiconductors, and provides uniform distribution of energy in radiant heating.
    Type: Grant
    Filed: October 23, 1987
    Date of Patent: May 9, 1989
    Assignee: The United States of America as represented by the United States Department of Energy
    Inventors: Timothy J. Drummond, David S. Ginley, Thomas E. Zipperian