Patents by Inventor Keith G. Barraclough

Keith G. Barraclough 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: 5349921
    Abstract: Semiconductor crystalline materials, e.g. silicon, GaAs, are grown from a melt, e.g. using the Czochralski technique where a seed crystal is dipped into the melt then slowly withdrawn. Rotation of the growing crystal (6) is partly responsible for convective flows within the melt (5). Convective flows are reduced while radial uniformity is improved by subjecting the crystal/melt interface to a shaped magnetic field. This magnetic field is rotationally symmetrical about the axis of crystal rotation, with a component of field parallel to this axis that is less than 500 gauss, preferably less than 200 gauss, with a value above 500 gauss at other parts of the melt. The field may be produced by two superconducting magnet coils (21, 22) spaced apart and arranged co-axially with the axis of crystal rotation.
    Type: Grant
    Filed: October 12, 1990
    Date of Patent: September 27, 1994
    Assignee: Her Majesty the Queen in right of Canada, as represented by The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland
    Inventors: Keith G. Barraclough, Robert W. Series
  • Patent number: 5212101
    Abstract: The invention provides a method of producing silicon with about 100% substitutionality of very high concentrations of carbon up to about 10.sup.21 cm.sup.-3, which has good quality recrystallized layers containing low levels of residual damage, and which avoids precipitation of mobile carbon. This method, compatible with current state-of-the-art VLSI silicon technology, comprises the sequential steps of: implanting a silicon wafer with carbon ions, and two step annealing of the implanted silicon wafer.
    Type: Grant
    Filed: November 6, 1991
    Date of Patent: May 18, 1993
    Assignee: Secretary of State for Defence in her Britannic Majesty's Government of the United Kingdom
    Inventors: Leigh T. Canham, Keith G. Barraclough, Mark R. Dyball
  • Patent number: 5077143
    Abstract: An electroluminescent silicon device comprises a light emitting diode (10). The diode (10) includes a p.sup.+ semiconductor contact (42) and a n.sup.- layer (32), forming a p-n junction (43) therebetween. The n.sup.- layer (32) is carbon-doped and irradiated with an electron beam having electrons with energies of between 150 and 400 keV to form G-centres. The diode (10) is electroluminescent when forward biassed, radiative recombination occuring at the G-centres. The invention reconciles the conflicting requirements of creating luminescent defect centres by irradiation while avoiding damage to electronic properties. The device may be an integrated light emitting diode (200) incorporated in a CMOS microcircuit. Photon output from the diode (200) may be relayed to other parts of a CMOS microcircuit by an integrated waveguide (224).
    Type: Grant
    Filed: November 6, 1989
    Date of Patent: December 31, 1991
    Assignee: The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingtom of Great Britain and Northern Ireland
    Inventors: Keith G. Barraclough, David J. Robbins, Leigh T. Canham