Characterization of nano Schottky junctions for a new structure of nano-electronic devices

There is an increasing interest in reducing the size of semiconductor devices to sub 20 nm scale for technical requirements, like low power consumption and high switching speed. Electronic devices based on nano Schottky junctions have the potential to address these issues. This is because nano metal-semiconductor contacts are expected to have narrower barriers compared to conventional Schottky diodes. Nano Schottky junctions have been investigated experimentally using gold (Au) coated AFM tips in contact with different silicon (Si) substrates. For nano-tips with an apex radius around 7 nm, the current-voltage (I-V) curves on low n-dope Si substrates have showed a reversed rectification diode behavior compared to the high n-dope Si samples. We have used a new theoretical model to study the electric field enhancement at the nano metal-semiconductor interface, and thus the enhancement of the tunneling current. We have found out that the tunneling current at the reverse bias is dominant on low dope substrates and very small on high dope substrates. This accounts for the reversed I-V rectification behavior on low dope Si Schottky contacts. The calculated I-V curves showed good agreement with the experimental results for both types of Si samples.