Evaluation procedure for fast and realistic assessment of plasma charging damage in thin oxides

The conventional gate leakage measurement may fail to provide clear evidence of plasma charging damage in case of low post-breakdown current in soft broken oxides. This has been resolved by introducing a high-bias, short-time pre-stress before the actual low-bias gate leakage measurement. With proper conditions this "high-low" procedure convincingly discriminates between damaged and non-damaged devices on the one hand, and between process steps on the other hand. To compare plasma damage in different gate oxides, prestress conditions should aim at fixed time-to-breakdown in each oxide. Using this methodology, realistic preliminary indication of P2ID alleviation in ultrathin oxides of future nodes has been obtained.