Gaussian Distribution on Electrical Characteristics of Al/SiO2/p-Si Structures

The Al/ /p-Si Schottky diodes (39 dots) with native interfacial insulator layer SiO2 were fabricated on the same Si wafer. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics of metal-oxide-semiconductor diodes, which are based on Al/SiO2/p-Si structures, have been measured at room temperature. Barrier height (BH), ideality factor (n) of these diodes has been calculated from their experimental forward bias current-voltage (I-V), reverse bias capacitance-voltage. Even though they are identically performed on the same quarter Si wafer, the calculated values of BH, which is obtained from I-V characteristic, have ranged from 0.687 to 0.772 eV and ideality factor n from 1.903 to 4.48. The values of barrier heights obtained from C-V characteristics range from 0.629 to 1.097 eV. It was found that the values of barrier height obtained C-V characteristics is larger than that of these values from I-V characteristics. The experimental values BH distribution obtained from I-V and C-2-V characteristics have been fitted by Gaussian function and their mean values of BHs have been calculated to be 0.730 and 0.863 respectively. Normal distribution of ideality factors mean value is 3.160 with standard deviation 0.689. Experimental results show that the interface states at a native insulator layer between metal and semiconductor play an important role in the value of the BH, ideality factor and the other electrical parameters of Schottky diodes.