Detection and comparison of localized states produced in poly-Si/ultra-thin oxide/silicon, structures by plasma exposure or plasma charging during reactive ion etching

An approach using two terminal current measurements obtained in a cyclic current-voltage sweeping procedure, is shown to be very useful in detecting damage in poly-Si/ultra-thin SiO₂/substrate Si gate structures subjected to dry etching. The current peaks seen in this approach, are shown to be due to displacement currents and to have different features depending on whether the capacitor structures were subjected to plasma charging currents, or plasma photon/particle exposure during etching. A model is presented relating these features to localized states at or near the SiO₂/substrate interface.