Sub-Femtoampere-Current Detection Using Single-Electron Sensor Operated Around 295 K

Sub-femtoampere (sub-fA) current was detected using a device based on a dynamic random access memory (DRAM) composed of silicon-on-insulator (SOI) field-effect transistors (FETs). The device incorporated a 20-aF capacitor connected to the FETs with a two-layer gate structure, which suppressed charge leakage from and to the capacitor to the theoretical limit. The capacitor captured a small number of electrons that constitute the sub-fA current. The captured electrons, approximately 10 in number, were read out by another FET acting as a charge sensor with single-electron resolution. Consequently, a current of 100 attoamperes was detected.