Abstract: A family of extremely fine-grained alloys are used to make coatings or free-standing bodies having desirable properties for use as a heat-resistant and wear-resistant material. In an illustrative embodiment, the alloys are comprised of a multiplicity of alternate, microcrystalline or nanocrystalline films of tungsten metal and tungsten compound. The tungsten compound film may be comprised of a tungsten carbide or a tungsten boride. The tungsten films are the primary films. Their desirable characteristics, in addition to their very fine crystalline habit, per se, are the high strength, high hardness, high resilience, and high fracture energy which these fine crystallites foster. They may be manufactured by a chemical vapor deposition process in which reactive gas flows are rapidly switched to produce alternate films with abrupt hetero-junctions and thereby to produce the useful micro-crystalline habit. The unique synthesis method allows effective control of critical flaw size.

Abstract: A process for producing a single-crystal silicon wafer, comprises the following steps: producing a layer on the front surface of the silicon wafer by epitaxial deposition or production of a layer whose electrical resistance differs from the electrical resistance of the remainder of the silicon wafer on the front surface of the silicon wafer, or production of an external getter layer on the back surface of the silicon wafer, and heat treating the silicon wafer at a temperature which is selected to be such that an inequality (1) [ O ? ? ? i ] < [ O ? ? ? i ] eq ? ( T ) ? exp ? ? ? 2 ? ? SiO ? 2 ? ? r ? ? ? k ? ? ? T is satisfied, where [Oi] is an oxygen concentration in the silicon wafer, [Oi]eq(T) is a limit solubility of oxygen in silicon at a temperature T, ?SiO2 is the surface energy of silicon dioxide, ? is a volume of a precipitated oxygen atom, r is a mean COP radius and k the Boltzmann constant, with the silicon wafer, during the heat treatment, at least part

Abstract: An SOI wafer, includes a substrate made from silicon, an electrically insulating layer with a thermal conductivity of at least 1.6 W/(Km) and a single-crystal silicon layer with a thickness of from 10 nm to 10 &mgr;m, a standard deviation of at most 5% from the mean layer thickness and a density of at most 0.5 HF defects/cm2.

Abstract: A process for the heat treatment of a silicon wafer, during which the silicon wafer is at least temporarily exposed to an oxygen-containing atmosphere, the heat treatment taking place at a temperature which is selected in such a way that the inequality 1 [ Oi ] < [ Oi ] eq ⁢ ( T ) ⁢ exp ⁢ ( 2 ⁢ σ SiO 2 ⁢ Ω rkT )