Patents by Inventor Lillian A. Rankel

Lillian A. Rankel 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).

  • Etching of group III-V semiconductors
    Patent number: 3947304
    Abstract: Group III-V compound semiconductor devices with attached gold conductor areas are etched using a basic ferricyanide etchant. The etchant is an aqueous solution containing ferricyanide ions in a concentration from 0.8 molar to 1.2 molar and sodium or potassium hydroxide in a concentration from 0.3 molar to 1.5 molar. This etchant rapidly removes the semiconductor material leaving smooth surfaces, while leaving the gold conductors and areas protected by oxide layers essentially intact. The use of titanium layers as etching masks, deposited for example by evaporating or sputtering through a removable mask, is also disclosed.
    Type: Grant
    Filed: August 15, 1972
    Date of Patent: March 30, 1976
    Assignee: Bell Telephone Laboratories, Incorporated
    Inventor: Lillian Rankel Plauger