Patents by Inventor Heinz-Achim Hefner

Heinz-Achim Hefner 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: 5587327
    Abstract: A process for preparing a bipolar transistor for very high frequencies is described, which is especially advantageous for the preparation of heterobipolar transistors and leads to components with low parasitic capacities and low base lead resistance. The process includes forming a structured first layer with collector zone and insulation areas surrounding the collector zone on a monocrystalline lead layer. A series of monocrystalline transistor layers are grown on the first layer over the collector zone by differential epitaxy and a series of polycrystalline layers is grown at the same time over the insulation areas. A series of polycrystalline layers is designed as a base lead.
    Type: Grant
    Filed: May 23, 1995
    Date of Patent: December 24, 1996
    Assignees: Daimler Benz AG, Temictelefunken Microelectronic GmbH
    Inventors: Ulf Konig, Andreas Gruhle, Andreas Schuppen, Horst Kibbel, Harry Dietrich, Heinz-Achim Hefner
  • Patent number: 5254484
    Abstract: A method for thermal annealing of amorphous surface layers on a single-crystal semiconductor base element. The amorphous surface layer is obtained by implantation of germanium or silicon ions in a single-crystal silicon base element. Finally, the amorphous layer is doped by implantation of impurities and subjected to a three-step annealing process. During the first step of this process, the interface region between the amorphous layer and the single-crystal base element is smoothed at a temperature between 400.degree. and 460.degree. C., in the second step the amorphous layer recrystallizes at a temperature between 500.degree. and 600.degree. C., and in the third step the dopants are activated in an RTA process.
    Type: Grant
    Filed: September 24, 1991
    Date of Patent: October 19, 1993
    Assignee: Telefunken electronic GmbH
    Inventors: Heinz-Achim Hefner, Joachim Imschweiler, Michael Seibt
  • Patent number: 4710264
    Abstract: In a process for manufacturing a semiconductor arrangement, wherein an uneven surface of the semiconductor arrangement is smoothened, there is produced on the uneven surface an insulating layer of such thickness that the insulating layer produced on the surface exhibits an even surface. The insulating layer is then partially removed again.
    Type: Grant
    Filed: November 17, 1986
    Date of Patent: December 1, 1987
    Assignee: Telefunken Electronic GmbH
    Inventors: Eckehard Waschler, Hermann Clauss, Heinz-Achim Hefner