Plasma-Induced Defect-Site Generation in Si Substrate and Its Impact on Performance Degradation in Scaled MOSFETs

Plasma-induced ion-bombardment damage was studied in terms of defect sites created underneath the exposed Si surface. From the shift of capacitance–voltage ($C$– $V$) curves, the defect sites were found to capture carriers (being negatively charged in the case of an Ar plasma exposure). This results in a change of the effective impurity-doping density and the profile. We also report that the defect density depends on the energy of ions from plasma. A simplified and quantitative model is proposed for the drain–current degradation induced by the series-resistance increase by the damage. The relationship derived between the defect density and the drain–current degradation is verified by device simulations. The proposed model is useful to predict the device performance change from plasma process parameters.