Electron trapping in buried oxides formed by oxygen implantation

Previous work has demonstrated how the capacitance/voltage characteristics of the SOI (silicon-on-insulator) structure can be used to interpret the effect of Fowler-Nordheim stressing of the buried oxide. The authors extend the previous work by reporting the effects of avalanche injection of electrons into the buried oxide. As the average electric fields in the oxide are low during avalanche injection (typically <3 MV/cm), the technique permits the characterization of intrinsic electron traps. The experiments were performed on SOI capacitor structures produced by oxygen implantation at 200 keV and an equivalent dose of 1.8×10¹⁸ O⁺ cm^-2 . The variation of the flatband voltage in the body and the substrate for an electron injection current density of 1.5×10^-6 A/cm² is shown. Two trapping centers with capture cross-sections of 8×10^-15 cm² and 1×10^-16 cm², with densities of 5×10¹¹ and 1×10¹², respectively, are revealed