Menso Hendriks

Plasma‐induced fixed oxide charge

The buildup of a plasma‐induced fixed oxide charge (Qf ) in thermally grown silicon dioxide on silicon was studied. Whereas samples located in the plasma showed a persistent instantaneous saturation behavior [Qf (sat) =1.3×1013 charges/cm2], those that were situated in a field‐free region outside the plasma produced dose and oxide thickness dependent buildup curves. A distinction is made between nonpenetrating electron/ion bombardments and penetrating photon irradiation. In the first case, the Qf creation can be explained by hole transport through the oxide film under the influence of an internally generated electric field and successive hole trapping near the interface. In the second case, we have to deal with direct interaction with the SiO2/Si interface. Furthermore, thermal annealing was used to reduce and/or eliminate plasma‐induced Qf. Activation energies of 0.51 and 0.58 eV were found for the annealing process.