Abstract: A method of producing ultrafine powders comprising metal silicide powder and the products produced by the method are disclosed. The ultrafine powders comprising metal silicide powders are ideally suited to form stable colloidal suspensions which are used in the production of conductive metal silicide containing films. The process employs gaseous reactants comprising a metal halide and a silicon-containing compound. The reactants are exposed to high intensity light to produce ultrafine powders. In addition to the production of metal silicide powders, the ultrafine powders may also include silicon powder and metal subhalide powder. The ultrafine powders are particularly suited for use in VLSI and VVLSI production.

Abstract: Finely divided, hydrogen-activated catalyst compositions comprising iron, silicon and carbon or iron and silicon that selectively convert gaseous mixtures of CO and H.sub.2, at a temperature of about 150.degree.-450.degree. C. and at pressures of about 10-2000 kPa, into a reaction mixture containing at least about 75% C.sub.2 -C.sub.6 alkenes and no more than about 25% of CH.sub.4 and undesirable CO.sub.2 by-products are disclosed. A wide range of iron/silicon-based catalyst compositions are conveniently prepared by laser pyrolysis and hydrogen-pretreatment and readily reactivated with hydrogen at elevated temperatures.

Abstract: Semiconductor doping compositions comprising a suspension of (a) a dopant material, in the form of finely divided spherical particles of narrow size distribution from about 0.1 D to D, where D is the diameter of the largest particle and is no more than about (1.mu.) comprising a member selected from the group consisting of B.sub.x Si.sub.y, B.sub.x N.sub.y, P.sub.x Si.sub.y, P.sub.x N.sub.y, As.sub.x Si.sub.y and Sb.sub.x Si.sub.y wherein x and y vary from about 0.001 to about 99.999 mole percent, (b) an effective amount of a thermally degradable polymeric organic binder such as polymethyl methacrylate; and (c) an amount of an organic solvent, such a cyclohexanone, sufficient to dissolve said polymeric organic binder, such as polymethylmethacrylate, and to disperse said dopant material are disclosed.

Abstract: Finely divided, hydrogen-activated catalyst compositions comprising iron, silicon and carbon or iron and silicon that selectively convert gaseous mixtures of CO and H.sub.2, at a temperature of about 150.degree.-450.degree. C. and at pressures of about 10-2000 kPa, into reaction mixture containing at least about 75% C.sub.2 -C.sub.6 alkenes and no more than about 25% of CH.sub.4 and undesirable CO.sub.2 by-products are disclosed. A wide range of iron/silicon-based catalyst compositions are conveniently prepared by laser pyrolysis and hydrogen-pretreatment and readily reactivated with hydrogen at elevated temperatures.