Analysis of the Inhomogeneous Barrier in In/p-Si Schottky Contact and Modified Richardson Plot

Abstract

The current-voltage (I-V) characteristics of In/p-Si Schottky barrier contact were measured over the temperature range 230-360 K with interval of 10 K. The calculated zero bias barrier height () and the ideality factor (n) using thermionic theory show strong temperature dependence. The experimental values of and n for In/p-Si Schottky contact range from 0.70 eV and 1.91 (at 360 K) to 0.49 eV and 2.99 (at 230 K) respectively. The conventional Richardson plot exhibits nonlinearity at lower temperature. The Richardson constant determined from intercept at the ordinate of this experimental linear portion is the value of 2.07 × 10 – 8 A/cm2K2 which is much lower than the theoretical value 32 A/cm2K2 for holes in p-type silicon. The temperature dependence of Schottky barrier characteristics of the contact was interpreted on the basis of the existence of Gaussian distribution of the barrier height around a mean value due to barrier height inhomogeneties prevailing at the metal semiconductor interface. The modified plot gives = 1.17 eV and A* = 31.16 A/cm2K2 with standard deviation = 0.16 V.