Oxide field and temperature dependences of gate oxide degradation by substrate hot electron injection

The hot-electron-limited gate oxide reliability is characterized as a function of the oxide electric field and temperature using substrate injection. Industrial oxides (950 degrees C partial steam, 900 degrees C dry, and 850 degrees C dry/wet/dry oxides) were investigated. Extensive measurements of the oxide field and temperature dependence of the charging, discharging, and generation rates from 77 to 373 K have shown that the charging of electron traps is enhanced at lower temperatures and at low fields. Trap generation was suppressed at 77 K. Electron trapping and tunnel emission measurements allow separation of the field- and thermal-stimulated electron detrapping rates at the oxide trap. A new isochronal electric-field-stimulated emission technique was employed to obtain the oxide-trap energy spectrum. The oxide electron traps are distributed in energy with a peak at 0.9 eV and a thermal activation energy of about 0.4 eV for electron detrapping.<>