A high-speed silicon-based few-electron memory with metal– oxide–semiconductor field-effect transistor gain element

Abstract

The design and operation of a single-electron transistor-controlled memory cell with gain provided by an integrated metal–oxide–semiconductor field-effect transistor is described. The field-effect transistor has a split gate, the central section of which is addressed by the single-electron transistor. This design effectively reduces the size of the cell’s memory node such that the memory states are represented by a difference of only a few hundred electrons, while obtaining output currents in the microamp range. The hysteresis loop in the field-effect transistor current shows clear step discontinuities which arise from Coulomb oscillations in the single-electron transistor’s drain-to-source current. The cell operates with write times as short as 10 ns and voltages of less than 5 V at 4.2 K, and operation persists to 45 K. The cell design is compact and the memory is fabricated in silicon-on-insulator material by processes that are compatible with current silicon fabrication methods.