Threshold Voltage Improvement and Gate Leakage Current Reduction in a Multi-dot Room Temperature Operating Single Electron Transistor (RT-SET)

摘要

The single-electron transistor (SET) is one of the best candidates for future nano electronic circuits because of its ultralow power consumption and small size. SET devices operate on the principle of Coulomb blockade, which is more prominent at dimensions of a few nano meters. Typically, the SET device consists of two capacitively coupled ultra small tunnel junctions with a nano island between them. The electron tunneling through the tunnel junctions can be controlled by the gate voltage. The drain current and the impact of the gate voltage depends on the overall capacitance of the device. Single electron transistors can be fabricated using methods like AFM nano oxidation, e-beam lithography, or shadow mask evaporation. Focused Ion Beam (FIB) based fabrication of SET devices is a novel method to produce SETs. The present paper describes the effect of additional series capacitance on the source-drain characteristic of a multi-dot room temperature operating SET device fabricated using FIB etch and deposition process. It also presents a novel method to minimize the gate leakage current and improve the threshold voltage in such multi-dot SET devices, operating at room temperature.