It was in a popular science magazine that they used radio wave to heat up silicon into vapors to make solar cells. The idea may be to do the same for a p type mixture to coat your substrate and build layers of the n type material on the chip. Laser epitaxy pinpoints the very atoms and moves them onto the surface of the chip to be deposited in layers to make the components on the chip. This may be a way to avoid the chemicals of I think it was Dichloroethylene or chemicals used to disolve or deposit or etch integrated circuit boards. Relying on laser to do the work that chemicals once did lower the impact of stored chemicals at manufacturing sites. The only waste would be nano particles that might be vacuumed up and smelted or reused if purity is controlled or to a mixture advantage by wavelength tuning to manipulated the atoms or molecules to make the chips at controlled frequency.