Impact of Domain Wall Motion on the Memory Window in a Multidomain Ferroelectric FET

This letter studies the impact of multi-domain dynamics on the memory window (MW) of a Ferroelectric FET (FeFET). The memory window primarily depends on the density of domains in the ferroelectric region. We show that a maximum MW is possible if one domain wall is present in the ferroelectric layer. Furthermore, enhancing the ferroelectric layer thickness decreases the gradient energy leading to an expansion in the domain period. This increased domain period reduces the domain density and improves the MW. On the other hand, domain density increases with the increase in dielectric layer thickness, which reduces the MW. Additionally, the nature of the domain wall also alters the MW remarkably, causing a reduction in the MW when the domain wall gradually switches from hard to soft. The optimum range of the device's physical parameters is obtained by minimizing the net ferroelectric thermodynamic energy corresponding to the maximum MW and serves as a device design guideline.