Abstract: Mechanical components, e.g. die and/or crucible or the like structures with which single silicon crystals are grown from the melt as shaped articles in thin sheet or ribbon geometry, are advantageously comprised, for their material of construction, of a suitable thermally stable and inert foundation substrate coated or provided on at least the silicon-contacting surface(s) thereof with a thin, uniform, integral surface layer deposit of pyrolitic silicon nitride (Si.sub.3 N.sub.4) obtained by the chemical vapor deposition (i.e., "CVD") technique.

Abstract: A susceptor for heating a plurality of semiconductor wafers, as by rf induction, comprises a hollow truncated pyramid of conventional graphite. The walls of the pyramid are planar except for ledges extending from the outer surfaces of the walls for supporting the wafers. A heat shield of pyrolytic graphite is fixed to the inner surface of the walls, directly behind each of the supported wafers. The heat shield has an area substantially coextensive and in alignment with the area of the wafer. The heat shields are anisotropic and are disposed with their low heat conducting directions extending in directions transversely to the surfaces of the walls so that the portions of the walls sandwiched between the wafers and the heat shields get hotter than the remaining portions of the walls.