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

Other

Solid State Scientific Corporation

Michael J Callahan

David F Bliss

John S Bailey

Michael J Suscavage

James A Fikse

Meckie T Harris

Buguo Wang

Gerald W Iseler

This invention provides a process for producing high-purity dense polycrystalline III-nitride slabs. A vessel which contains a group III-metal such as gallium or an alloy of group III-metals of shallow depth is placed in a reactor. The group III-metal or alloy is heated until a molten state is reached after which a halide-containing source mixed with a carrier gas and a nitrogen-containing source is flowed through the reactor vessel. An initial porous crust of III-nitride forms on the surface of the molten III-metal or alloy which reacts with the nitrogen-containing source and the halide-containing source. The flow rate of the nitrogen-containing source is then increased and flowed into contact with the molten metal to produce a dense polycrystalline III-nitride. The products produced from the inventive process can be used as source material for III-nitride single crystal growth which material is not available naturally.

Polycrystalline III-nitrides

A method of hydrothermally synthesizing sapphire single crystals doped with trivalent metal ions in a crystal-growth autoclave including a crystal-growth zone and nutrient-dissolution zone in fluid communication with the crystal-growth zone is provided. Implementations of the method including situating within the crystal-growth zone at least one sapphire-based seed crystal and situating within the nutrient-dissolution zone an aluminum-containing material to serve as nutrient. An acidic, trivalent-metal-ion-containing growth solution is introduced into the cavity in a quantity sufficient, at least when heated to a predetermined average temperature, to immerse the at least one seed crystal and the nutrient in the growth solution. The growth solution is selected such that sapphire exhibits retrograde solubility therein and the growth process is carried out while maintaining an interior-cavity pressure within a range between and including each of 3.5 kilopounds per square inch and 25 kilopounds per square inch and while maintaining a temperature differential between the crystal-growth and nutrient-dissolution zones such that the average temperature within the crystal-growth zone is higher than the average temperature within the nutrient-dissolution zone.

Hydrothermal methods of fabricating trivalent-metal-ion-doped sapphire 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

This invention provides a process and apparatus for producing products of M-nitride materials wherein M&equals;gallium (GaN), aluminum (AlN), indium (InN), germanium (GeN), zinc (ZnN) and ternary nitrides and alloys such as zinc germanium nitride or indium aluminum gallium nitride. This process and apparatus produce either free-standing single crystals, or deposit layers on a substrate by epitaxial growth or polycrystalline deposition. Also high purity M-nitride powders may be synthesized. The process uses an ammonium halide such as ammonium chloride, ammonium bromide or ammonium iodide and a metal to combine to form the M-nitride which deposits in a cooler region downstream from and/or immediately adjacent to the reaction area. High purity M-nitride can be nucleated from the vapor to form single crystals or deposited on a suitable substrate as a high density material. High purity M-nitride single crystals can be grown by the direct reaction of the halide with the M-metal in a range of sizes from a few micrometers to centimeters, depending on the growth conditions. The small sized crystals are recovered as high purity M-nitride powder while the larger crystals can be prepared as substrates for electronic devices or UV/blue/green emitting diodes and lasers. The deposited layers can be used as M-nitride substrates, or targets for pulsed laser deposition (PLD), or other systems requiring high density targets. The deposition process, and subsequent density of the resulting component, is controlled by the reaction medium and by adjusting the temperature of the ammonium halide in an area near but separate from the reaction zone. Thickness of deposition on the substrates by the same process involves placement of the substrates in a suitable area in the reaction chamber and may be further controlled by the use of nitrogen, nitrogen-hydrogen mixtures or other suitable controlling gas to facilitate uniform distribution of the layer.

Process and apparatus for the growth of nitride materials

Using a GaN growth furnace, at least three different techniques can be used for forming the targets for the deposition of thin films. In the first, nitrides can be deposited as a dense coating on a target backing plate for use as a target. In this approach, the backing plate is placed near the Group III metal. During processing, the Group III metal or metal halide vaporizes and reacts with the nitrogen source to deposit a dense polycrystalline layer on the backing plate. To build up a thick layer on the backing plate, the backing plate is repeatedly placed in the processing furnace until a satisfactory thickness is attained. For the second approach, a properly shaped reaction vessel, the dense, thick Group III nitride crust that forms on top of the Group III metal during the process can be used directly or mechanically altered to meet the size requirements for a sputtering target holder. As a third approach, the Group III nitride material can be ground into a fine powder using traditional ceramic powder processing methods and then pressed to consolidate the powder into a sputtering target. The third processing option would typically lead to a low density target; however, this 'green' compact can then be reinserted into the same processing apparatus that the original powder was synthesized to infiltrate the open pores with the same or another group III metal nitride. This would produce a high density, thick target.

Process for the manufacture of group III nitride targets for use in

A resin extruder for supplying resin to flaws in laminated glass includes a casing forming a resin reservoir from which resin is dispensed through a nozzle by screwing inward a ram partially received in the casing and carrying a pressure gauge communicating with the reservoir.

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Hanson, MA, United States of America

Michael J Callahan