Electron Trapping in Ion-Implanted Silicon Dioxide Films on Silicon.

摘要

Photoelectric and MOS capacitance -voltage techniques were used to investigate the properties of electron traps created in SiO2films by ion implantation. The samples consisted of MOS structures with either Al or Ne ions shallowly implanted into the oxide layer. Unannealed Al-implanted and Ne-implanted SiO2films possessed much larger concentrations of electron traps than were found in unimplanted control samples. The trapping centers introduced by the ion implantation were acceptor-like in that they acquired negative charge after capturing an electron,thereby giving rise to positive flatband voltages. From the existence of electron traps in Ne-implanted oxides,and from a substantial reduction in electron trapping after thermal anneal of Al-implanted samples,it is concluded that a large proportion of the traps are associated with displacement damage created by the ion implantation. In both Al-implanted and Ne-implanted oxides, photodepopulation of the electron traps required photon energies above 4.0eV. (Author)