ELECTRICAL-CONDUCTION OF BURIED SIO2 LAYERS ANALYZED BY PHOTON-STIMULATED ELECTRON-TUNNELING

The conductivity of buried SiO2 layers produced by implantation of oxy gen 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 ener gy level 2.8 eV below the oxide conduction band. The dark and photon i nduced currents show a correlated dependence on the electric held stre ngth in the oxide, and both increase with the Si enrichment of the oxi de, thus advancing the isolated defects as the common origin of both c urrents. The same defects were also observed in thermally grown and de posited oxides, so they appear as intrinsic imperfections related to t he excess silicon in SiO2. (C) 1997 American Institute of Physics.