Room-temperature single-electron charging phenomena in large-area nanocrystal memory obtained by low-energy ion beam synthesis

We investigated the dependence of implantation dose on the charge storage characteristics of large-area n-channel metal–oxide–semiconductor field-effect transistors with 1-keV ${\mathrm{Si}}^{+}$ -implanted gate oxides. Gate bias and time-dependent source–drain current measurements are reported. Devices implanted with ${\text{1×10}}^{16}\hspace{0.17em}{\mathrm{cm}}^{\text{−2}}$ Si dose exhibit a continuous (trap-like) charge storage process under both static and dynamic conditions. In contrast, for ${\text{2×10}}^{16}\hspace{0.17em}{\mathrm{cm}}^{\text{−2}}$ implanted devices, electrons are stored in Si nanocrystals in discrete units at low gate voltages, as revealed by a periodic staircase plateau of the source–drain current with a low gate voltage sweep rate, and the step-like decrease of the time-dependent monitoring of the channel current. These observations of room-temperature single-electron storage effects support the pursuit of large-area devices operating on the basis of Coulomb blockade phenomena.