Analysis of the Resistance of Silicon Nanoscale Structures Highly Doped in Different Configurations

In this study, two types of silicon (Si) nanoscale-channel transistors were fabricated with high-concentration doping and their low-temperature current-voltage characteristics were evaluated in order to clarify the influence of channel design and doping conditions on the electrical conduction. The measured results of the resistance for nano-channels doped by phosphorus (P) donors were analyzed as a function of the actual channel width estimated from scanning electron microscope (SEM) images to reveal the impact of low dimensionality on the electrical properties of Si nanostructures. Although some weak signatures of Coulomb blockade transport are observed in a few devices doped with P-donors, these devices mostly behave as metallic resistors. On the other hand, devices with the nano-channels codoped with both P-donors and boron (B) acceptors exhibit Coulomb blockade features with high yield. These results can lead to further studies towards single-charge tunneling in silicon nano-transistors in which both donors and acceptors interplay in the formation of quantum dots (QDs).