Schottky barrier lowering in Mo/n-Si contacts at the reverse bias

Abstract

We have investigated I-V characteristics of nearly ideal Schottky contacts Mo/n-Si by power exponent method in order to determine physical phenomena which bear responsibility for reverse current soft behavior. The static and differential resistances as functions of reverse bias were studied. They allowed to obtain power exponent depending on the applied reverse bias. The absolute values of Schottky barrier lowerings were found up to 50 V. Nonlinear regression analysis was used for determining of basic effects, which give rise to barrier lowering in Mo/n-Si contacts. There are interfacial image forces and dipole effect, created by electric field increasing at the metal-semiconductor boundary owing to reverse voltage growth. The largest absolute value of barrier lowering is equal to 4.8 kT (0,12 eV) at 50 V and not exceed by 18% of zero-bias Schottky barrier height. It is established that thermoionic-field emission and barrier height inhomogeneities are not substantial in comparison with both above-mentioned effects.