Electrical properties and modeling of ultrathin impurity-doped silicon dioxides

Abstract

The electrical properties of silicon dioxides doped with impurities (fluorine and/or nitrogen) are investigated in this article. Pure silicon dioxide (SiO2), fluorine-doped silicon oxide (SiOF), nitrogen-doped silicon oxide (SiON), and nitrogen-doped SiOF (SiOFN) are our choices for investigation in this study. The oxide films are prepared from liquid-phase-deposited fluorinated silicon oxides under O2 or N2O annealing. The leakage current as a function of applied voltage for impurity-doped oxides was simulated using a generalized trap-assisted tunneling (GTAT) model at moderate fields of 5–8 MV/cm. Two important parameters, trap energy level Φt and trap concentration Nt, are directly derived by this model from simple current–voltage characteristics. The relationships of Φt and Nt on various experimental conditions (annealing temperature, time, gases, and initial oxide thickness) are comprehensively studied based on GTAT modelings.