AN ASSESSMENT ON ELECTRICAL CHARACTERIZATION OF Ni/n-Si SCHOTTKY RECTIFIERS WITH AND WITHOUT Ta2O5 INTERFACIAL OXIDE LAYER

We have fabricated Ni/n-Si metal-semiconductor (MS) and Ni/Ta2O5/n-Si metal-insulator-semiconductor (MIS) Schottky barrier diodes at room temperature and studied their current density-voltage (J-V) and capacitance-voltage (C-V) characteristic properties. The forward bias J-V characteristics of the fabricated MS and MIS devices have been evaluated with the help of the thermionic emission (TE) mechanism. Schottky barrier height (SBH) values of 0.73 and 0.84 eV and ideality factor values of 1.75 and 1.46 are extracted using J-V measurements for MS and MIS Schottky barrier diodes without and with Ta2O5 interfacial oxide layer, respectively. It was noted that the incorporation of Ta2O5 interfacial oxide layer enhanced the value of SBH for the MIS device because this oxide layer produced the substantial barrier between Ni and n-Si and this obtained barrier height value is better than the conventional metal/n-Si (MS) Schottky diodes. The rectification ratio (RR) calculated at +/- 2 V for the MS structure is found to be 1.27 x 10(1) and the MIS structure is found to be 7.39 x 10(2). Using Chung's method, the series resistance (R-s) values are calculated using dV/dln(I) vs I plot and are found to be 21,603 Omega for the Ni/n-Si (MS) and 5489 Omega for the Ni/Ta2O5/n-Si (MIS) structures, respectively. In addition, H(I) vs I plot has been utilized to evaluate the series resistance (R-s) values and are found to be 14,064 Omega for the Ni/n-Si (MS) and 2236 Omega for the Ni/Ta2O5/n-Si (MIS) structures, respectively. In conclusion, by analyzing the experimental results, it is confirmed that the good quality performance is observed in Ni/Ta2O5/n-Si (MIS) type SBD when compared to Ni/n-Si (MS) type SBD and can be accredited to the intentionally formed thin Ta2O5 interfacial oxide layer between Nickel and n-type Si.