Quantitative Evaluation of Gate Oxide Damage during Plasma Processing Using Antenna-Structure Capacitors

Plasma-induced damage of gate oxides is evaluated from the difference between the intrinsic charge-to-breakdown (Q BD) and the residual Q BD. This difference, ΔQ BD, corresponds to the plasma-induced damage to the oxide and to the accumulation of conduction current from the plasma into the oxide. It is shown experimentally that the plasma-induced damage ΔQ BD increases in proportion to the antenna ratio (exposed antenna area/gate area). The ΔQ BD of the antenna capacitor depends not on the device structures such as the gate oxide thickness, but on the plasma process conditions.