Patents by Inventor Frederic W. Voltmer

Frederic W. Voltmer 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 of growing single crystal silicon by the Czochralski method which eliminates the need for post growth annealing for resistivity stabilization
    Patent number: 4140570
    Abstract: This disclosure relates to a technique of improving the quality of crystals grown by the Czochralski method by substantially eliminating the formation of electrically active oxygen complexes during growth. The oxygen which forms these complexes is liberated from the quartz liner which contains the silicon melt. It has been found that electrically active oxygen complexes (oxygen donors) are formed in the silicon lattice during crystal growth when the crystal is in the range of 300-500.degree. C. Above and below this temperature range, the formation of oxygen donors in the silicon lattice is minimal. The crystal is therefore maintained in its entirety above the temperature of 500.degree. C. and then is quenched to be quickly brought below the 300.degree. C. level. In this way, the silicon crystal is in the 300.degree. C. to 500.degree. C. range for a minimal period of time, thereby minimizing the amount of oxygen donor formation in the silicon lattice during growth.
    Type: Grant
    Filed: November 19, 1973
    Date of Patent: February 20, 1979
    Assignee: Texas Instruments Incorporated
    Inventors: Frederic W. Voltmer, Thomas G. Digges, Jr.