Oxide traps in Si-SiO2structures characterized by tunnel emission with deep-level transient spectroscopy

The possibility of characterizing the traps of the oxide layer near the Si/${\mathrm{SiO}}_2$ interface using deep-level transient spectroscopy (DLTS) is pointed out. By use of the so-called saturating-pulse DLTS, an unusual increase of the DLTS spectrum is observed. This behavior is interpreted by taking into account tunneling emission from oxide traps situated near the silicon dioxide–silicon interface (≊10 to 30 Å). By introducing a model for the derivation of the DLTS signal amplitude, we show here how the deconvolution between interface states and oxide traps is allowed. Then, from the experimental study of the filling kinetics the concentration of these oxide traps is obtained (≊${10}^7$ to ${10}^8$ ${\mathrm{cm}}^{\mathrm{-}2}$) as well as their associated tunneling capture cross section (≊${10}^{\mathrm{-}22}$ to ${10}^{\mathrm{-}21}$ ${\mathrm{cm}}^2$). Moreover, by variation of the emission rate window, it is possible to measure the concentration profile of these oxide traps. The validity of the model and measurements are extensively discussed.