US Patent 7244513 - Porous silicon powder used to make nanoparticles

http://www.freepatentsonline.com/7244513.html

Patent claims to intermediate products used in a manufacturing process often may be preferred over claiming the process itself since claims to structure may often be easier to enforce than claims to methods. This patent from Nano Proprietary is directed toward an intermediate product used in the formation of silicon nanoparticles. Claim 1 reads:

1. A porous silicon powder comprising a plurality of silicon particles wherein only the outermost layers of said particles are porous, and wherein the outermost porous layers of said silicon particles comprise a thickness which ranges from at least about 1 angstrom to at most about 500 nanometers.