Advanced Technology Materials, Inc.

Martin Marietta Corporation

Walter Precht

Delwyn F Cummings

Richard Koba

Donald Kupp

K Sharvan Kumar

A semiconductor wafer base is disclosed which is suitable for fabrication of devices in silicon carbide, comprising a single crystal substrate which is a transition metal carbide alloy having cubic crystal structure and an unpolytyped, single crystal 3C-silicon carbide overlay epitaxially related to the substrate. Preferably, the substrate is an alloy of two or more of titanium carbide, tantalum carbide, vanadium carbide, and niobium carbide, with lattice parameter differing from 3C-silicon carbide by less than about 1%. Use of the transition metal carbide alloys enables the preparation of large, single crystal substrates free from cracks, dislocations, or other defects, suitable for epitaxial deposition of 3C-silicon carbide. The 3C-silicon carbide epitaxial overlay may be deposited by any suitable technique, including chemical vapor deposition and reactive evaporation, and may be doped with n- or p-type dopants. The 3C-silicon carbide is useful for fabricating semiconductor devices for use at high temperatures, high powers, and in corrosive environments.

Wafer base for silicon carbide semiconductor devices, incorporating

A semiconductor wafer base is disclosed which is suitable for fabrication of devices in silicon carbide, comprising a single crystal substrate which is a transition metal carbide alloy having cubic crystal structure and an unpolytyped, single crystal 3C-silicon carbide overlay epitaxially related to the substrate. Preferably, the substrate is an alloy of two or more of titanium carbide, tantalum carbide, vanadium carbide, and niobium carbide, with alttice parameter differing from 3C-silicon carbide by less than about 1%. Use of the transition metal carbide alloys enables the preparation of large, single crystal substrates free from cracks, dislocations, or other defects, suitable for epitaxial deposition of 3C-silicon carbide. The 3C-silicon carbide epitaxial overlay may be deposited by any suitable technique, including chemical vapor deposition and reactive evaporation, and may be doped with n- or p-type dopants. The 3C-silicon carbide is useful for fabricating semiconductor devices for use at high temperatures, high powers, and in corrosive environments.

Intermetallics capable of use as structural elements, exhibiting relatively high ductility and low brittleness, comprise ternary and quaternary TiAl.sub.3 alloys of the general formulae Al--Ti--M and Al--Ti--M--M', wherein M is selected from Cu, Ni, and Fe, M' is selected from V, Nb, and Ta. Such materials exhibit cubic, Ll.sub.2 crystal structures.

Multicomponent, low density cubic L1.sub.2 aluminides

A process for pretreating metal powders for the preparation of dispersion hardened metal alloys whereby an iron, cobalt or nickel base metal powder is homogeneously mixed with a chromium powder and with a prealloyed metal carbide powder and granulated to a powder granulate. The granulate is then classified and reduced to remove oxygen present therein.

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Towson, MD, United States of America

Walter Precht