Investigation of the interface state densities of p-Si/SiO2/Al structures prepared by the application of various constant currents

SUMMARY In this study, (111) oriented, p-type and resistivity of 10,5-19,5 Ohm-cm. of single crystal of silicon was used. The polished faces of the crystals were oxidized by anodic oxidation method under various constant current conditions. In the anodic oxidation of silicon, the solutions: 0,6 M NaCl + 0,3 M Na2S04 were used. The value of pH of the electrolyte was calculated and was determined, as pH=6,50. During the anodic oxidation procedure, the voltage-time values were measured. The oxidized samples were coated with aluminium in the vacuum chamber system under the pressure of 10"5 Torr. The values of the capacity- voltage of Al / anodic oxide / p-Si (MOS) structures were measured at room temperature. Ideal capacity-voltage curves were plotted for each sample and they were compared with experimental curves. The surface states of the samples were calculated by comparing the differences between the ideal and experimental curves. The interface properties were determined by making use of C-Vg characteristics of the MOS structures. It was observed that all of the samples a, b and c showed ionic type hysteresis. The ionic type hysteresis of sample indicates that the oxides contain mobile ions.