Gravity-free crystal prodn - in vacuo and esp in natural or artificial space vehicle

摘要

Very high purity single crystals of si or other semiconductor materials are made in outer space under vacuum and free from gravitational distortion of the intermolecular bonds during the crystallization. The melt is in the form of a ball and energy is provided by alternating inductive or capacitative electric fields, by focussing the suns rays by a mirror, or more esp. by multiple electron bombardment by pairs of beams. Either zone refining or more esp. centrifugal refining may be used. In the latter case a torque is imparted to the melt by moving the electron beams and the impurities collect on an equatorial belt.