Patents by Inventor Raul D. Cuellar

Raul D. Cuellar 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: 4855636
    Abstract: A miniaturized field emitter vacuum tube device and method of making are described. The device includes a needle-shaped field emitter cathode, metal gate and electron collecting anode, which are enclosed by an insulating chamber which is evacuated. The gate electrode may be used to form the insulator-to-metal vacuum seal. Device isolation is achieved by using a highly resistive polycrystalline silicon film. A method of making a field emitter cathode tip is described in which two masking and etching steps form a pair of intersecting lines, the intersection point forming the cathode tip.
    Type: Grant
    Filed: October 8, 1987
    Date of Patent: August 8, 1989
    Inventors: Heinz H. Busta, Raul D. Cuellar
  • Patent number: 4685996
    Abstract: A method of making a field emitter includes anisotropically etching a single crystal silicon substrate to form at least one funnel-shaped protrusion on the substrate, then conformally depositing a refractory metal onto the funnel-shaped protrusion. Alternatively, single crystal silicon may be anisotropically etched to form at least one funnel-shaped recess in the silicon. The etched surface is doped with an impurity to form an etch-stop layer, the remaining undoped silicon is removed, then the etch-stop layer is conformally deposited with a refractory metal. The funnel-shaped recess can then be back-filled with silicon or another suitable material.
    Type: Grant
    Filed: October 14, 1986
    Date of Patent: August 11, 1987
    Inventors: Heinz H. Busta, Raul D. Cuellar