Regrowth of amorphous regions in semiconductors by sub-threshold electron beams

Abstract

Spatially isolated amorphous zones produced in Si, Ge and Gal' by low energy, low dose ion implantations can be regrown at room temperature by using an electron beam to stimulate the process. The rate at which these zones regrow is dependent on the energy of the electron beam and on the size of the amorphous zone produced by the implant. In the three materials, the rate of regrowth decreases as the energy of the electron beam increases from 25 keV reaching a minimum below the threshold displacement energy. The rate then increases as the energy of the electron beam increases. Electron beam heating effects have been calculated and shown to be insignificant. To account for these observations, the possible role of defects in the amorphous and crystalline material migrating to the amorphous—crystalline interface, and of defects at the amorphous-crystalline interface in causing regrowth are considered.