NONTHERMAL EFFECTS OF PHOTON ILLUMINATION ON SURFACE-DIFFUSION

Nonthermal influences of photon illumination on surface diffusion at h igh temperatures have been measured experimentally for the first time. Activation energies and preexponential factors for diffusion of germa nium and indium on silicon change substantially in response to illumin ation by photons having energies greater than the substrate band gap. Results depend on doping type, Ionization of surface vacancies by phot ogenerated charge carriers seems to play a key role. The results have significant implications for aspects of microelectronics fabrication g overned by surface mobility.