Electrical conduction of buried SiO2 layers analyzed by photon stimulated electron tunneling

The conductivity of buried SiO2 layers produced by implantation of oxygen ions into silicon was compared with the photon stimulated electron tunneling from Si into SiO2. The latter process is found to originate from defects located in interfacial SiO2 layers with an electron energy level 2.8 eV below the oxide conduction band. The dark and photon induced currents show a correlated dependence on the electric field strength in the oxide, and both increase with the Si enrichment of the oxide, thus advancing the isolated defects as the common origin of both currents. The same defects were also observed in thermally grown and deposited oxides, so they appear as intrinsic imperfections related to the excess silicon in SiO2. (C) 1997 American Institute of Physics.