Production of Fine Ceramic Powders from Chloromethylsilanes Using Pulsed Excimer Radiation

Abstract

Ceramic powders have been produced by the photodecomposition of chloromethylsilanes using a pulsed excimer laser operating at 193 nm. These feedstocks are cheaper and easier to handle than SiH 4 , the main feedstock used in earlier work using continuous–wave CO 2 lasers as the irradiation source. Powders were produced from photolysis of silanes containing methyl groups without the addition of any coreagents, while the two silanes tested containing only chlorine and hydrogen ligands, SiCI 3 H and SiCI 4 , required the addition of H 2 as a coreagent for significant yields of powder to be produced. The powders produced were found to be low in chlorine, with amorphous Si powders or β‐SiC being produced depending on feedstock. Particle sizes measured from electron micrographs varied from less than 10 nm to 1.5 μm.