Electron Charge Sensor with Hole Current Operating at Cryogenic Temperature

When SOI-PMOS functions like a capacitor-less 1T-DRAM cell, it is possible for the number of electrons to be sensed at cryogenic temperatures (5K). We developed a structure that combines SOI-NMOS and SOI-PMOS with multiple gates to form a silicon quantum-dot array. In this structure, a variable number of electrons is injected into the SOI-PMOS body transporting them by means of the bucket-brigade operation of SOI-NMOS connected in series. The channel-hole current was changed by the injected electrons due to the body bias effect in SOI-PMOS, and the change appeared to be step-like, suggesting a dependence on the elementary charge.