Single crystal and quasi-single crystal, composition, apparatus, and associated method

a single crystal and quasi-single crystal technology, applied in the direction of nanoinformatics, polycrystalline material growth, under protective fluid, etc., can solve the problems of unfavorable single crystal growth, low growth rate achievable in conventional autoclaves, undetectable low, etc., to achieve low concentration of impurities, high growth rate, and high quality

Inactive Publication Date: 2006-02-23
SORAA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Control of spontaneous nucleation may be problematic using a non-epitaxial substrate, which may prevent the growth of desirable single crystals.
However, the growth rate achievable using conventional autoclaves at mild conditions (temperature less than about 550 degrees Celsius, and pressure less than about 6 kbar) may be undesirably low, and the use of more extreme conditions may require specialized equipment.
However, the vapor pressure of nitrogen gas in contact with the molten gallium may be undesirably high at temperatures sufficiently high for viable crystal growth rates.
In addition, the growth rates may be undesirably low due to the low solubility and the low diffusion coefficient of nitrogen in molten gallium metal.
The relatively low solubility may limit crystal grow rate and / or maximum crystal size.
Static configurations used for crystal growth, where there is no motion between the hot zone and the growing crystal, may limit crystal grow rate and / or maximum crystal size.
However, the solubility of nitrogen in the flux is relatively low.
The dynamic process may be difficult to control because the flux may become supersaturated with respect to gallium nitride formation, and because of spontaneous nucleation of gallium nitride crystals remote from the seed crystal.

Method used

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  • Single crystal and quasi-single crystal, composition, apparatus, and associated method
  • Single crystal and quasi-single crystal, composition, apparatus, and associated method
  • Single crystal and quasi-single crystal, composition, apparatus, and associated method

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0103] Commercial grade gallium nitride powder, having a nominal purity of 99.9%, is mixed with lithium nitride (Li3N) powder in a 6:1 ratio by weight. The mixed powders are pressed into a pill, wrapped in tantalum foil, and placed inside a magnesium oxide outer capsule reaction vessel. The encapsulated powders are placed in a cell and pressed at about 50 kbar to about 1500 degrees Celsius in a belt-type press apparatus for about 15 minutes. The reaction vessel is cooled and opened. The gallium nitride crystals are separated from the lithium nitride flux by washing with water and HNO3. The gallium nitride crystals are approximately 20 microns in size. X-ray diffraction patterns obtained for the gallium nitride starting material and the gallium nitride crystals that are grown under high pressure / high temperature conditions are listed in Table 1.

TABLE 1X-Ray diffraction patterns for GaN starting material and GaN crystalsgrown under high pressure / high temperature conditions.GaNGaNGro...

example 2

[0105] Commercially available gallium nitride powder, having the same nominal purity and relatively poor crystallinity as described in Example 1, is compacted into a pill weighing about 1.4 g. Ammonium iodide (NH4I) powder is compacted into a second pill weighing 2.6 g. The two pills are placed into a reaction vessel. The reaction vessel may include two opposing cups fabricated from hot-pressed boron nitride. The reaction vessel is then placed within a cell and treated at high pressure and high temperature in a temperature gradient cell in a belt-type press apparatus. The pressure is approximately 30 kbar. The temperature of the top of the cell is about 1435 degrees Celsius, and the temperature at the bottom of the cell is about 1360 degrees Celsius. After a treatment time of about 20 hours, the cell is cooled and removed from the press. Residual NH4I is washed out of the cell with water, leaving residual gallium nitride powder and well-crystallized gallium nitride crystals having a...

example 3

[0106] Gallium nitride powder is compacted into a pill weighing about 1.25 g. A second pill is compacted from a mixture may include about 2.6 g of ammonium iodide (NH4I) powder to about 0.1 grams of gallium nitride powder. The two pills are placed into a reaction vessel that includes two opposing cups fabricated from hot-pressed boron nitride. The reaction vessel is placed within a cell and treated at high pressure and high temperature in a belt-type press apparatus, and in which a temperature gradient zone is created and relative to the crucible. At one point during the procedure, the pressure is approximately 40 kbar and the temperature of the top of the cell is about 1450 degrees Celsius, while the temperature at the bottom of the cell is about 1375 degrees Celsius. After a treatment time of 24 hours, the cell is cooled and removed from the press. Residual NH4I is washed out of the cell with water, leaving residual gallium nitride powder and well-crystallized gallium nitride crys...

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Abstract

A single crystal or quasi-single crystal including one or more Group III material and an impurity. The impurity includes one or more elements from Group IA, Group IIA, Groups IIIB to VIIB, Group VIII, Group IB, Group IIB, or Group VIIA elements of the periodic table of elements. A composition for forming a crystal is also provided. The composition includes a source material comprising a Group III element, and a flux comprising one or more of P, Rb, Cs, Mg, Ca, Sr, Ba, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Pd, Ag, Hf, Ta, W, Pt, Au, Hg, Ge, or Sb; or the flux may comprise a rare earth metal.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation-in-part of application Ser. No. 10 / 063,164, filed Mar. 27, 2002, and claims benefit therefrom, the contents of which are incorporated by reference in their entirety.BACKGROUND [0002] 1. Technical Field [0003] The invention includes embodiments that may relate to a single crystal and quasi-single crystal. The invention includes embodiments that may relate to a composition for forming single crystal and quasi-single crystal. The invention includes embodiments that may relate to an apparatus for forming single crystal and quasi-single crystal. The invention includes embodiments that may relate to a method for forming single crystal and quasi-single crystal. [0004] 2. Discussion of Related Art [0005] Quasi-single crystal nitrides may be grown by vapor-phase methods, which may employ non-nitride substrates as seeds or substrates to produce quasi-single crystals. Vapor-phase methods may include hydride or ha...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C30B15/00C30B30/04C30B28/10C30B27/02C30B21/06C30B9/00C30B9/06C30B29/38
CPCB82Y10/00B82Y30/00C30B9/00Y10T117/1052C30B29/406C30B7/00Y10T117/1096C30B29/403C30B29/40
Inventor D'EVELYN, MARK PHILIPPARK, DONG-SILLOU, VICTOR LIENKONGMCNULTY, THOMAS FRANCIS
Owner SORAA
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