Patents by Inventor Wilfried V. Ammon

Wilfried V. Ammon 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).

  • Method for the crucible-free floating zone pulling of semiconductor rods and an induction heating coil therefor
    Patent number: 4851628
    Abstract: A method for pulling silicon semiconductor rods, in particular having diaers of 10cm and over. The current methods of crucible-free float zoning or float zone pulling can be markedly improved if the molten cap like zone which develops is forced inwardly in the growth process. This is accomplished with the aid of electromagnetic forces in an annular zone situated opposite the coil slot. The electromagnetic forces can be achieved by using induction heating coils whose coil surface facing the molten cap is provided with annular segments whose thickness increases from their inner periphery ouotwardly and which are disposed opposite the coil slot above the peripheral region of the molten cap.
    Type: Grant
    Filed: December 8, 1988
    Date of Patent: July 25, 1989
    Assignee: Wacker-ChemiTronic Gesellschaft fur Elektronik-Grundstoffe mbH
    Inventors: Wilfried V. Ammon, Wolfgang Hensel, Heinz Klinger