| The operation of silicon quantum-dot based flash memory devices are simulated numerically with emphasis on energy and charge quantization in the quantum-dot. The simulation involves the self-consistent solution of three-dimensional (3-D) Poisson and Kohn-Sham equations within the density functional formalism, where the quantum many-body interactions are treated according to the local-density approximation. We investigate the quantum-dot electronic structure, device capacitance-voltage characteristics and derive the threshold voltage, VT, variation with single-electron charging as a function of design parameters. In the simulation of a single rectangular quantum-dot floating gate, we focus on the effects on the wrap-gate on the onset of inversion and analyzed the influence of the extent of the control gate overlap on the charging behavior of the device. We have also investigated the operation of the nano-crystal memory. We show that the unique combination of symmetries in the band-structure and the nano-crystal geometry can produce interesting stark effect. The effects of geometry and strain, based on the continuum strain approach and the deformation potential theory, on single-electron charging in 100Å-diameter nano-crystals of various shapes has been simulated. |
