Effect of oxygen plasma treatment on the electrical characteristics of Pt/n-type Si Schottky diodes

The electrical properties of Pt/n-type Si Schottky diodes fabricated from n-type Si wafers subjected to an oxygen (O₂) plasma treatment were investigated as a function of the power of the O₂ plasma. The Pt/n-type Si Schottky diode with an O₂ plasma treatment at a power of 100 W showed better rectifying characteristics with increasing barrier height and decreasing ideality factor compared to the conventional Pt/n-type Si Schottky diodes. This could be attributed to an improvement in the interface homogeneity associated with damage-free surface smoothing driven by the O₂ plasma treatment at a power of 100 W. On the other hand, with increasing power of the O₂ plasma for powers above 150 W, the barrier height decreased and the leakage current increased, indicating degradation of the device performance. The degradation in the rectifying properties after the O₂ plasma treatment at a higher plasma power in excess of 150 W could be associated with increases in the series resistance and the interface state density caused by plasma-induced damage to the Si surface.