Northrop Grumman Systems Corporation

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

Vijay Balakrishna

Richard H Hopkins

Godfrey Augustine

R Noel Thomas

Narsingh Bahadur Singh

Walter E Gaida

Dennis R Suhre

H McDonald Hobgood

Nils C Fernelius

Pure silicon feedstock is melted and vaporized in a physical vapor transport furnace. In one embodiment the vaporized silicon 46 is reacted with a high purity carbon member 74, such as a porous carbon disc, disposed directly above the silicon. The gaseous species resulting from the reaction are deposited on a silicon carbide seed crystal 50 axially located above the disc, resulting in the growth of monocrystalline silicon carbide 56. In another embodiment, one or more gases, which may include a carbon-containing gas, are additionally introduced at 84 into the furnace, such as into a reaction zone above the disc, to participate in the growth process.

Advanced physical vapor transport method and apparatus for growing high

Method and apparatus for growing semiconductor grade silicon carbide boules (84). Pure silicon feedstock (36) is melted and vaporized. The vaporized silicon is reacted with a high purity carbon-containing gas (64), such as propane, and the gaseous species resulting from the reaction are deposited on a silicon carbide seed crystal (50), resulting in the growth of monocrystalline silicon carbide.

Method and apparatus for growing high purity single crystal silicon

A new method for improving the mechanical properties and nonlinear optical performance characteristics of gallium selenide crystals (GaSe) is disclosed. A charge of GaSe crystals was doped with indium before being made into a crystal. The indium-doped GaSe crystals have improved physical properties in that they can be cut along the cleave planes and the cleaved surfaces polished without the usual delaminations typically observed in prior art pure GaSe crystals. The indium-doped crystals were tested in a second harmonic generation (SHG) system and found to have nearly twice the SHG efficiency as pure, or undoped, GaSe crystals.

Modified gallium selenide crystals for high power nonlinear optical

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Monroeville, PA, United States of America

Vijay Balakrishna