Simulation and experimental studies of electrical characteristics of nano metal–semiconductor interfaces

Understanding the characteristics of nano metal–semiconductor (M–S) Schottky contact is crucial for developing nano electronic devices at sub 50-nm scale. Nano M-S contacts show a non-conventional current-voltage (I-V) behavior compared to the planar–Schottky contacts. This effect is attributed to the enhanced tunneling current due to the narrowing of the barrier width that results from the enhanced electric field at the nano M-S interface. In this work, we show that such nano Schottky junctions are sensitive to different doping concentrations of n-type semiconductor substrates, as well as to the metal nano contact size. The low doped concentration substrate increases the possibility of free electrons in the metal to tunnel through the thin junction barrier to the conduction band of the semiconductor. We have incorporated this effect in a simulation model of nano metal-semiconductor junctions to see the change in the I-V behavior. The model was examined using a conductive Atomic Force Microscope (C-AFM) with a gold coated nano tip, where the IV data was generated for two types of n-Si substrates, and then compared with the simulation model.