Understanding the impact of polysilicon percolative conduction on 3D NAND variability

In this work, by means of 3D TCAD simulations, we analyze the effects of the trap-induced percolative conduction in the polysilicon channels of 3D NAND memory cells. We demonstrate that the discrete nature of traps at polysilicon grain boundaries affects the memory cell threshold voltage and its fluctuation, as well as the random telegraph noise, with larger impact than is predicted by a continuous-trap approach. Our results highlight the importance of discrete-trap modeling for accurate variability prediction.