Evaluation technique of gate oxide damage

Gate oxide damage by the plasma process is studied using test structures with various length antennas. It is shown that the gate oxide damage by the plasma process can be monitored quantitatively by measuring the charge to breakdown Q_BD. From Q _BD measurements, it is found that degradation occurs in the duration of over-etching, not in main etching. The breakdown spot in the gate oxide is detected by the photon emission method. The breakdown caused by plasma damage occurs at the local oxidation of silicon (LOCOS) edge. LOCOS structure plays an important role for the degradation by plasma damage