Laser conversion of high purity silicon powder to densified granular forms

A method for converting high purity silicon powder into a polysilicon granule of a desired size and of a desired shape, the method comprising:

• (a) providing a dry source of high purity silicon powder;
• (b) providing a process substrate comprising a recess having a defined size and shape, the defined size and shape being the size and shape required to form the polysilicon granule of the desired size and the desired shape;
• (c) feeding a selected amount of dry silicon powder into the recess of the process substrate, the selected amount of dry silicon powder being the amount required to form the polysilicon granule of the desired size and the desired shape;
• (d) heating the dry silicon powder disposed in the recess with a laser emitting light at a wavelength in the range of ultraviolet to near infrared for a selected time and at a selected power so as to cause local melting, densification and solidification, whereby to form a polysilicon granule of the desired size and the desired shape, wherein the polysilicon granule has a diameter greater than about 2 mm and less than 5 mm;
• and
• (e) discharging the polysilicon granule from the process substrate.