Detection of a single-charge defect in a metal-oxide-semiconductor structure using vertically coupled Al and Si single-electron transistors

摘要

By using a vertically coupled Al and Si single-electron-transistor (SET) system in a metal-oxide-semiconductor structure, we have detected a single-charge defect which is tunnel coupled to the Si SET. By solving a simple electrostatic model, the fractions of each coupling capacitance associated with the defect are extracted. The results reveal that the defect size is small, corresponding to a sphere with a radius less than 1 nm, suggesting the defect is most likely an interface trap. Based on the ratios of the coupling capacitances, the trap is estimated to be about 20 nm away from the Si SET.