Semi-Analytical Model for the Transient Operation of Gate-All-Around Charge-Trap Memories

We present a detailed semi-analytical investigation of the transient dynamics of gate-all-around (GAA) charge-trap memories. To this aim, the Poisson equation is solved in cylindrical coordinates, and a modification of the well-known Fowler–Nordheim formula is proposed for tunneling through cylindrical dielectric layers. Analytical results are validated by experimental data on devices with different gate stack compositions, considering a quite extended range of gate biases and times. Finally, the model is used for a parametric analysis of the GAA cell, highlighting the effect of device curvature on both program/erase and retention.