Effect of series resistance on the electrical characteristics and interface state energy distributions of Sn/ p-Si (MS) Schottky diodes

Abstract

In this study, electrical characteristics of the Sn/ p-type Si (MS) Schottky diodes have been investigated by current–voltage ( I– V) and capacitance–voltage ( C– V) measurements at room temperature. The barrier height obtained from C– V measurement is higher than obtained from I– V measurement and this discrepancy can be explained by introducing a spatial distribution of barrier heights due to barrier height inhomogeneities, which are available at the nanostructure Sn/ p-Si interface. A modified Norde’s function combined with conventional forward I– V method was used to extract the parameters including barrier height (Φ b ) and the series resistance ( R S ). The barrier height and series resistance obtained from Norde’s function was compared with those from Cheung functions. In addition, the interface-state density ( N SS ) as a function of energy distribution ( E SS – E V ) was extracted from the forward-bias I– V measurements by taking into account the bias dependence of the effective barrier height (Φ b ) and series resistance ( R S ) for the Schottky diodes. While the interface-state density ( N SS ) calculated without taking into account series resistance ( R S ) has increased exponentially with bias from 4.235 × 10 12 cm −2eV −1 in ( E SS – 0.62) eV to 2.371 × 10 13 cm −2eV −1 in ( E SS – 0.39) eV of p-Si, the N SS obtained taking into account the series resistance has increased exponentially with bias from of 4.235 × 10 12 to 1.671 × 10 13 cm −2eV −1 in the same interval. This behaviour is attributed to the passivation of the p-doped Si surface with the presence of thin interfacial insulator layer between the metal and semiconductor.