United States of America As Represented by the Secretary of the Air Force

Massachusetts Institute of Technology

The United States of America

Gerald W Iseler

Brian S Ahern

David F Bliss

Vladimir L Tassev

Harry R Clark

David W Weyburne

Michael J Suscavage

John S Bailey

Michael J Callahan

Harry R Clark, Jr

The invention provides for growing semiconductor and other crystals by loading a vessel in its lower portion with a seed crystal, loading a charge thereon in the vessel, heating the charge to a molten state and electromagnetically stirring the melt using magnetic and electric fields to obtain a more uniform composition of melt and slowly reducing the temperature of the melt over the crystal to grow a more uniform crystal from such stirred melt.

Growth of uniform crystals

Method and apparatus are provided for forming metal nitrides (MN) wherein M is contacted with iodine vapor or hydrogen iodide (HI) vapor to form metal iodide (MI) and contacting MI with ammonia to form the MN in a process of reduced or no toxicity. MN is then deposited on a substrate, on one or more seeds or it can self nucleate on the walls of a growth chamber, to form high purity metal nitride material. The inventive MN material finds use in semiconductor materials and in making nitride electronic devices as well as other uses.

Forming metal nitrides

An instrument for forming nanometric features on surfaces of materials having a motor driven support for moving a workpiece on an X-Y-Z axis, a scribing tool of nanometric proportion engagable with the workpiece and a laser system for sensing movement. The tool is mounted on piezoelectric actuating means and the entire system is under the control of a programmed computer processing unit.

Method and apparatus for forming nanometric features on surfaces

A wafer cutting device has a plurality of individually highly tensioned diamond impregnated wires that are mounted in a translatable head. Each wire has a tension monitor connected thereto for the purpose of insuring uniform tension and also alerting to breakage. Further, a differential DC voltage is applied to the wires and the crystal with the assistance of electrolytes to improve the removal of material for minimizing damage to the surfaces. The crystal is mounted on a two dimensional stage. During normal cutting the crystal is moved vertically into the cutting wire. The vertical cutting rate is adjusted due to the configuration of the crystal. At the end of cutting, the crystal is moved laterally so as to place a notch in the wafers for the purpose of removing the wafer in a clean break.

Wafer cutting device

Apparatus for forming nanometric features on surfaces

A telescoping low vibration pulling mechanism for use in Czochralski crystal growth apparatus, comprising a broached bushing which defines an internal circumference of teeth therein, which teeth cooperate with complimentary teeth defined on the circumference of a splined shaft. The bushing is coupled to a motor drive via a hollow tube and the splined shaft, couplable to a seed shaft and an elevation assembly, telescopes through said bushing within said hollow tube.

Growing community of inventors

Chelmsford, MA, United States of America

Gerald W Iseler