The present invention is a method of forming large device quality single crystals of silicon carbide. The sublimation process is enhanced by maintaining a constant polytype composition in the source materials, selected size distribution in the source materials, by specific preparation of the growth surface and seed crystals, and by controlling the thermal gradient between the source materials and the seed crystal.

Sublimation of silicon carbide to produce large, device quality single crystals of silicon carbide

Growth of high purity AlN crystals

Beta-silicon carbide whiskers are being grown by a vapour-liquid-solid (VLS) process which produces a very high purity, high strength single crystal fibre about 6μm in diameter and 5–100 mm long. Details of the growth process are given along with a general explanantion of the effects of the major growth parameters on whisker growth morphology.

Growth of beta-silicon carbide whiskers by the VLS process

Planar graphite has been extensively studied by Raman scattering for years. A comparative Raman study of several different and less common non-planar graphitic materials is given here. New kinds of graphite whiskers and tubular graphite cones (synthetic and natural) have been introduced. Raman spectroscopy has been applied to the characterization of natural graphite crystal edge planes, an individual graphite whisker, graphite polyhedral crystals and tubular graphite cones. Almost all of the observed Raman modes were assigned according to the selection rules and the double-resonance Raman mechanism. The polarization properties related to the structural features, the line shape of the first-order dispersive mode and its combination modes, the frequency variation of some modes in different carbon materials and other unique Raman spectral features are discussed here in detail.

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Raman scattering of non-planar graphite: arched edges, polyhedral crystals, whiskers and cones.

A boule formed by high rate vapor phase growth of Group III-V nitride boules (ingots) on native nitride seeds (Figure 1), from which wafers may be derived for fabrication of microelectronic structures (Figure 5). The boule is of microelectronic device quality, e.g., having a transverse dimension greater than 1 centimeter, a length greater than 1 millimeter, and a top surface defect density of less than 107 defects cm-2. The Group III-V nitride boule may be formed by growing a Group III-V nitride material on a corresponding native Group III-V nitride seed crystal by vapor phase epitaxy at a growth rate above 20 micrometers per hour.

Iii-v nitride substrate boule and method of making and using the same

Growth of SiC whiskers in the system SiO2-C-H2nucleated by iron

Phase transformations, habit changes and crystal growth in SiC

Columnar growth of carbon

A method of forming aluminum nitride single crystals of large area and silicon carbide-aluminum nitride heterojunctions using a modified Lely method. Aluminum nitride is introduced, as a vapor phase, into a furnace containing a plate-shaped monocrystal of silicon carbide at a temperature between 1800 DEG and 2300 DEG C. At those temperatures, aluminum nitride recrystallizes and condenses to deposit epitaxially on the silicon carbide. If the silicon carbide is of one conductivity type, the aluminum nitride can be suitably doped to be of the opposite conductivity type whereby a heterojunction is formed.

Gerrit Verspui

Papers

Growth of SiC whiskers in the system SiO2-C-H2nucleated by iron

Phase transformations, habit changes and crystal growth in SiC

Columnar growth of carbon

Method of manufacturing aluminium nitride crystals for semiconductor devices

Lanthanum-stimulated high-temperature whisker growth of α-SiC