A study of the breakdown testing of thermal silicon oxides and the effects of preoxidation surface treatment

The properties of 175 Å thermal oxides have been studied using three testing methods (constant voltage, constant current, and ramped voltage) under a wide range of stressing conditions, along with wafer level statistics. Thus, the role of stress levels of accelerated testing and the effects of wafer surface treatment could be examined. In particular, a constant charge-to-breakdown Q_bd at low voltage and current stress levels is identified. The effect of preoxidation surface treatment is investigated using different wafer cleans, deliberate contamination, and other process variables such as dry and wet oxidations