Patents by Inventor Craig M. Ransom

Craig M. Ransom 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: 5242859
    Abstract: A method is provided for diffusion doping of semiconductor chips and wafers, in particular silicon chips and wafers, at peak concentrations of greater than about 3.times.10.sup.19 atoms/cm.sup.3. The semiconducting material to be doped is placed in a furnace wherein the furnace contains an atmosphere of a carrier gas and a dopant containing gas. The doping containing gas is greater than about 0.1 volume percent of the total volume in the furnace chamber. The pressure of the composite gas is greater than about 0.1 Torr. The composite gas has an oxidizing agent concentration of less than about 1 part per million. The method permits the direct doping of a silicon surface to form a shallow n-doped region having a high peak concentration by a diffusion process thereby eliminating damage to the silicon surface from ion implantation which is the commonly used method to achieve these high doping concentrations. Since the method is nondirectional trench sidewalls can be doped at high concentrations.
    Type: Grant
    Filed: July 14, 1992
    Date of Patent: September 7, 1993
    Assignee: International Business Machines Corporation
    Inventors: Joseph F. Degelormo, Paul M. Fahey, Thomas N. Jackson, Craig M. Ransom, Devendra K. Sadana