Patents by Inventor Gisela Lang

Gisela Lang 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: 6309953
    Abstract: A process for producing a semiconductor device includes the following sequential steps: producing a semiconductor body having an AlxGa1−xAs layer with an upper surface, where x≦0.40; applying a contact metallization made of a non-noble metallic material to the AlxGa1−xAs layer; precleaning a semiconductor surface to produce a hydrophilic semiconductor surface; roughening the upper surface of the AlxGa1−xAs layer by etching with an etching mixture of hydrogen peroxide ≧30% and hydrofluoric acid ≧40% (1000:6) for a period of from 1 to 2.5 minutes; and re-etching with a dilute mineral acid. According to another embodiment, 0≦x≦1 and the upper surface of the AlxGa1−xAs layer is roughened by etching with nitric acid 65% at temperatures of between 0° C. and 30° C.
    Type: Grant
    Filed: March 2, 2000
    Date of Patent: October 30, 2001
    Assignee: Siemens Aktiengesellschaft
    Inventors: Helmut Fischer, Gisela Lang, Reinhard Sedlmeier, Ernst Nirschl
  • Patent number: 6281031
    Abstract: A semiconductor wafer, after having been provided with a multiplicity of optoelectronic semiconductor structures, is severed into a number of individual chips by abrasive cutting. After cutting, the chip flanks are etched with the chip surface protected. First, a covering layer is deposited over the entire surface of the semiconductor wafer which is provided with the diode structures. The covering layer is structured in such a manner that the covering layer is removed at the areas defined as cutting tracks. Then the semiconductor wafer is cut into individual chips by abrasive cutting with a cutting tool. The cutting tool is guided along the cutting tracks by appropriately moving the semiconductor wafer and the cutting tool relative to one another.
    Type: Grant
    Filed: February 16, 1999
    Date of Patent: August 28, 2001
    Assignee: Siemens Aktiengesellschaft
    Inventors: Josef Maurer, Gisela Lang
  • Patent number: 6140248
    Abstract: A process for producing a semiconductor device includes the following sequential steps: producing a semiconductor body having an Al.sub.x Ga.sub.1-x As layer with an upper surface, where x.ltoreq.0.40; applying a contact metallization made of a non-noble metallic material to the Al.sub.x Ga.sub.1-x As layer; precleaning a semiconductor surface to produce a hydrophilic semiconductor surface; roughening the upper surface of the Al.sub.x Ga.sub.1-x As layer by etching with an etching mixture of hydrogen peroxide.gtoreq.30% and hydrofluoric acid.gtoreq.40% (1000:6) for a period of from 1 to 2.5 minutes; and re-etching with a dilute mineral acid. According to another embodiment, 0.ltoreq.x.ltoreq.1 and the upper surface of the Al.sub.x Ga.sub.1-x As layer is roughened by etching with nitric acid 65% at temperatures of between 0.degree. C. and 30.degree. C.
    Type: Grant
    Filed: August 25, 1997
    Date of Patent: October 31, 2000
    Assignee: Siemens Aktiengesellschaft
    Inventors: Helmut Fischer, Gisela Lang, Reinhard Sedlmeier, Ernst Nirschl